Observing Archives

August 2, 2013December 23, 2015 by David Dickinson

The Astronomy of the Dog Days of Summer

Looking east from latitude 30 north on August 3rd, 30 minutes before sunrise. (Created by the author in Stellarium).

Can you feel the heat?

It’s not just your imagination. The northern hemisphere is currently in the midst of the Dog Days of Summer. For many, early August means hot, humid days and stagnant, sultry nights.

The actual dates for the Dog Days of Summer vary depending on the source, but are usually quoted as running from mid-July to mid-August. The Old Farmer’s Almanac lists the Dog Days as running from July 3^rd through August 11^th.

But there is an ancient astronomical observation that ties in with the Dog Days of Summer, one that you can replicate on these early August mornings.

The sky was important to the ancients. It told them when seasons were approaching, when to plant crops, and when to harvest. Ancient cultures were keen observers of the cycles in the sky. Cultures that were “astronomically literate” had a distinct edge over those who seldom bothered to note the goings on overhead.

The flooded Temple of Isis on the island of Philae circa 1905. (Credit: Wikimedia Commons under an Attribution-Share Alike 2.5 license. Author H.W. Dunning).

Sirius was a key star for Egyptian astronomers. Identified with the goddess Isis, the Egyptian name for Sirius was Sopdet, the deification of Sothis. There is a line penned by the Greco-Roman scholar Plutarch which states:

“The soul of Isis is called ‘Dog’ by the Greeks.”

Political commentary? A mis-translation by Greek scholars? Whatever the case, the mythological transition from “Isis to Sothis to Dog Star” seems to have been lost in time.

These astronomer-priests noted that Sirius rose with the Sun just prior to the annual flooding of the Nile. The appearance of a celestial object at sunrise is known as a heliacal rising. If you can recover Sirius from behind the glare of the Sun, you know that the “Tears of Isis” are on their way, in the form of life-giving flood waters.

Sopdet as the personification of Sirius (note the star on the forehead) Wikimedia Commons image under an Attribution Share Alike 3.0 license. Author Jeff Dahl).

In fact, the ancient Egyptians based their calendar on the appearance of Sirius and what is known as the Sothic cycle, which is a span of 1,461 sidereal years (365.25 x 4) in which the heliacal rising once again “syncs up” with the solar calendar.

It’s interesting to note that in 3000 BC, the heliacal rising of Sirius and the flooding of the Nile occurred around June 25^th, near the summer solstice. This also marked the Egyptian New Year. Today it occurs within a few weeks of August 15^th, owing to precession. (More on that in a bit!)

By the time of the Greeks, we start to see Sirius firmly referred to as the Dog Star. In Homer’s Iliad, King Priam refers to an advancing Achilles as:

“Blazing as the star that cometh forth at Harvest-time, shining forth amid the host of stars in the darkness of the night, the star whose name men call Orion’s Dog”

The Romans further promoted the canine branding for Sirius. You also see references to the “Dog Star” popping up in Virgil’s Aenid.

Over the years, scholars have also attempted to link the dog-headed god Anubis to Sirius. This transition is debated by scholars, and in his Star Names: Their Lore and Meaning, Richard Hinckley Allen casts doubt on the assertion.

Sirius as the shining "nose" of the constellation Canis Major. (Created by the author using Starry Night). — Sirius as the shining “nose” of the constellation Canis Major. (Created by the author using Starry Night).

Ancient cultures also saw the appearance of Sirius as signifying the onset of epidemics. Their fears were well founded, as summer flooding would also hatch a fresh wave of malaria and dengue fever-carrying mosquitoes.

Making a seasonal sighting of Sirius is fun and easy to do. The star is currently low to the southeast in the dawn, and rises successively higher each morning as August rolls on.

The following table can be used to aid your quest in Sirius-spotting.

Latitude north	Theoretical date when Sirius can 1^st be spotted
32°	August 3^rd
33°	August 4^th
34°	August 5^th
35°	August 6^th
36°	August 7^th
37°	August 8^th
38°	August 9^th
39°	August 10^th
40°	August 11^th
41°	August 12^th
42°	August 13^th
43°	August 14^th
44°	August 15^th
45°	August 16^th
46°	August 17^th
47°	August 18^th
48°	August 19^th
49°	August 20^th
50°	August 21^st

Thanks to “human astronomical computer extraordinaire” Ed Kotapish for the compilation!

Note that the table above is perpetual for years in the first half of the 21^st century. Our friend, the Precession of the Equinoxes pivots the equinoctial points to the tune of about one degree every 72 years. The Earth’s axis completes one full “wobble” approximately every 26,000 years. Our rotational pole only happens to be currently pointing at Polaris in our lifetimes. Its closest approach is around 2100 AD, after which the north celestial pole and Polaris will begin to drift apart. Mark your calendars—Vega will be the pole star in 13,727 AD. And to the ancient Egyptians, Thuban in the constellation Draco was the Pole Star!

Near Luxor (Photo by author). — The Colossi of Memnon Near Luxor, just one of the amazing architectural projects carried out by the ancient Egyptians. (Photo by author).

Keep in mind, atmospheric extinction is your enemy in this quest, as it will knock normally brilliant magnitude -1.46 Sirius a whopping 40 times in brightness to around magnitude +2.4.

Note that we have a nice line-up of planets in the dawn sky (see intro chart), which are joined by a waning crescent Moon this weekend. Jupiter and Mars ride high about an hour before sunrise, and if you can pick out Mercury at magnitude -0.5 directly below them, you should have a shot at spotting Sirius far to the south.

And don’t be afraid to “cheat” a little bit and use binoculars in your quest… we’ve even managed on occasion to track Sirius into the broad daylight. Just be sure to physically block the Sun behind a building or hill before attempting this feat!

Sirius as seen via Hubble- can you spy Sirius B? (NASA/ESA Hubble image). — Sirius as seen via Hubble- can you spy Sirius B? (Credit: NASA/ESA Hubble image).

Of course, the heliacal rising of Sirius prior to the flooding of the Nile was a convenient coincidence that the Egyptians used to their advantage. The ancients had little idea as to what they were seeing. At 8.6 light-years distant, Sirius is the brightest star in Earth’s sky during the current epoch. It’s also the second closest star visible to the naked eye from Earth. Only Alpha Centauri, located deep in the southern hemisphere sky is closer. The light you’re seeing from Sirius today left in early 2005, back before most of us had Facebook accounts.

Sirius also has a companion star, Sirius B. This star is the closest example of a white dwarf. Orbiting its primary once every 50 years, Sirius B has also been the center of a strange controversy we’ve explored in past writings concerning Dogon people of Mali.

Sirius B is difficult to nab in a telescope, owing to dazzling nearby Sirius A. This feat will get easier as Sirius B approaches apastron with a max separation of 11.5 arc seconds in 2025.

Some paleoastronomers have also puzzled over ancient records referring to Sirius as “red” in color. While some have stated that this might overturn current astrophysical models, a far more likely explanation is its position low to the horizon for northern hemisphere observers. Many bright stars can take on a twinkling ruddy hue when seen low in the sky due to atmospheric distortion.

Let the Dog Days of Summer (& astronomy) begin! (Photo by author).

All great facts to ponder during these Dog Days of early August, perhaps as the sky brightens during the dawn and your vigil for the Perseid meteors draws to an end!

July 28, 2013September 29, 2016 by David Dickinson

A Weird West Tale and the Hunt for Planet Vulcan

A hypothetical Vulcanoid asteroid in orbit about the Sun. ( Artist's impression in the Public Domain).

One of the most fascinating stories in modern astronomy involves the pursuit of a world that never was.

Tomorrow marks the 135^th anniversary of the total solar eclipse of July 29^th, 1878. With a maximum totality of 3 minutes 11 seconds, this eclipse traced a path across western Canada and the United States from the territory of Montana to Louisiana.

A curious band of astronomers also lay in wait along the path of totality, searching for an elusive world known as Vulcan.

Long before Star Trek or Mr. Spock, Vulcan was a hypothetical world thought to inhabit the region between the planet Mercury and the Sun.

The tale of Vulcan is the story of the birth of modern predictive astronomy. Vulcan was a reality to 18^th century astronomers- it can be seen and the astronomy textbooks and contemporary art and culture of the day. Urbain J.J. Le Verrier proposed the existence of the planet in 1859 to explain the anomalous precession of the perihelion of the planet Mercury. Le Verrier was a voice to be taken seriously — he had performed a similar feat of calculation to lead observers to the discovery of the planet Neptune from the Berlin Observatory on the night of September 23, 1846. Almost overnight, Le Verrier had single-handedly boosted astronomy into the realm of a science with real predictive power.

An 1863 photograph of Lescarbault's country house observatory. (Wikimedia Commons image in the public domain). — An 1863 photograph of Lescarbault’s country house observatory. (Wikimedia Commons image in the public domain).

The idea of Vulcan gained traction when a French doctor and amateur astronomer Edmond Lescarbault claimed to have seen the tiny world transit the Sun while viewing it through his 95 millimetre refractor on the sunny afternoon of March 26^th, 1859. Keep in mind, this was an era when solar observations were carried out via the hazardous method of viewing the Sun through a smoked or oil-filled filter, or the via safer technique of projecting the disk and sketching it onto a piece of paper.

A early right-angle solar viewer from the South Carolina State Museum in Columbia, South Carolina. Note the vent holes in the back to disappate heat and word SUN stenciled on the side! (Photo by author). — A early right-angle solar viewer from Robert Ariail collection at the South Carolina State Museum in Columbia, South Carolina. Note the vent holes in the back to dissipate heat, and word SUN stenciled on the side! (Photo by author).

A visiting Le Verrier was sufficiently impressed by Lescarbault’s observation, and went as far as to calculate and publish orbital tables for Vulcan. Soon, astronomers everywhere were “seeing dots” pass in front of the Sun. Astronomer F. A. R. Russell spotted an object transiting the Sun from London on January, 29^th, 1860. Sightings continued over the decades, including a claim by an observer based near Peckeloh Germany to have witnessed a transit of Vulcan on April 4^th, 1876.

Incidentally, we are not immune to this effect of “contagious observations” even today — for example, when Comet Holmes brightened to naked eye visibility in October 2007, spurious reports of other comets brightening flooded message boards, and a similar psychological phenomena occurred after amateur astronomer Anthony Wesley recorded an impact on Jupiter in 2010. Though the event that triggered the initial observation was real, the claims of impacts on other bodies in the solar system that soon followed turned out to be bogus.

Possible "target zone" for the existence of Vulcan, and later Vulcanoid asteroids. — Possible “target zone” for the existence of Vulcan, and later Vulcanoid asteroids. (Graphic in the public domain).

Still, reports of the planet Vulcan were substantial enough for astronomers to mount an expedition to the territory of Wyoming in an attempt to catch dim Vulcan near the Sun during the brief moments of totality. Participants include Simon Newcomb of the Naval Observatory, James Craig Watson and Lewis Swift. Inventor Thomas Edison was also on hand, stationed at Rawlins, Wyoming hoping to test his new-fangled invention known as a tasimeter to measure the heat of the solar corona.

Conditions were austere, to say the least. Although the teams endured dust storms that nearly threatened to cut their expeditions short, the morning of the 29^th dawned, as one newspaper reported, “as slick and clean as a Cheyenne free-lunch table.” Totality began just after 4 PM local, as observers near the tiny town of Separation, Wyoming swung their instruments into action.

Such a quest is difficult under the best of circumstances. Observers had to sweep the area within 3 degrees of the Sun (six times the diameter of a Full Moon) quickly during the fleeting moments of totality with their narrow field refractors, looking for a +4^thmagnitude star or fainter among the established star fields.

Map of the path of the total solar eclipse of July 29th, 1878. (Credit: Fred Espenak/NASA/GSFC).

In the end, the expedition was both a success and a failure. Watson & Swift both claimed to have identified a +5^th magnitude object similar in brightness to the nearby star Theta Cancri. Astronomer Christian Heinrich Friedrich Peters later cast doubt on the sighting and the whole Vulcan affair, claiming that “I refuse to go on a wild goose chase after Le Verrier’s mythical birds!”

And speaking of birds, Edison ran into another eclipse phenomenon while testing his device, when chickens, fooled by the approaching false dusk came home to roost at the onset of totality!

Vulcan search map for the Smithsonian Obervatory's 1900 eclipse expedition. (From the collection of Michael Zeiler @EclipseMaps, used with permission). — Vulcan search map for the Smithsonian Observatory’s 1900 eclipse expedition. (From the collection of Michael Zeiler @EclipseMaps, used with permission).

But such is the life of an eclipse-chaser. Albert Einstein’s general theory of relativity explained the precession of Mercury’s orbit in 1916 and did away with a need for Vulcan entirely.

But is the idea of intra-Mercurial worldlets down for the count?

The search strategy for NASA's high-altitude mission to hunt for Vulcanoids in 2002. (Credit: NASA/Dryden). — The search strategy for NASA’s high-altitude mission to hunt for Vulcanoids in 2002. (Credit: NASA/Dryden).

Amazingly, the quest for objects inside Mercury’s orbit goes on today, and the jury is still out. Dubbed Vulcanoids, modern day hunters still probe the inner solar system for tiny asteroids that may inhabit the region close to the Sun. In 2002, NASA conducted a series of high altitude flights out of the Dryden Flight Research Center at Edwards Air Force Base, California, sweeping the sky near the Sun for Vulcanoids at dawn and dusk. Now, there’s a job to be envious of — an F-18 flying astronomer!

One of NASA's fleet of high-performance F-18 aircraft. (Credit: NASA). — One of NASA’s fleet of high-performance F-18 aircraft. (Credit: NASA).

NASA’s MESSENGER spacecraft was also on the lookout for Vulcanoids on its six year trek through the inner solar system prior to orbital insertion on March 18^th, 2011.

Thus far, these hunts have turned up naught. But one of the most fascinating quests is still ongoing and being carried out by veteran eclipse-chaser Landon Curt Noll.

Mr. Noll last conducted a sweep for Vulcanoids during total phases of the long duration total solar eclipse of July 22^nd, 2009 across the Far East. He uses a deep sky imaging system, taking pictures in the near-IR to accomplish this search. Using this near-IR imaging technique during a total solar eclipse requires a stable platform, and thus performing this feat at sea or via an airborne platform is out. Such a rig has been successful in catching the extremely thin crescent Moon at the moment it reaches New phase.

Mr. Noll explains the aspects of an eclipse during a 2006 expedition to Libya. (Coutesy of Landon Curt Noll, used with permission).

To date, no convincing Vulcanoid candidates have been found. Mr. Noll also notes that the European Space Agency/NASA’s joint Solar Heliospheric Observatory (SOHO) spacecraft has, for all intents and purposes, eliminated the possibility of Vulcanoids brighter than +8^th magnitude near the Sun. Modern searches during eclipses conducted in this fashion scan the sky between wavelengths of 780 to 1100 nanometres down to magnitude +13.5. Mr. Noll told Universe Today that “Our improved orbital models show that objects as small as 50m in diameter could reside in a zone 0.08 A.U. to 0.18 AU (1.2 to 2.7 million kilometers) from the Sun.” He also stated that, “there is plenty of ‘room’ for (Vulcanoids) in the 50 metre to 20 kilometre range.”

Vulcanoid search diagram — The modern day Vulcanoid search strategy. (Diagram courtesy of Landon Curt Noll, used with permission).

Mr. Noll plans to resume his hunt during the August 21^st, 2017 total solar eclipse spanning the continental United States. Totality for this eclipse will have a maximum duration of 2 minutes and 40 seconds. Circumstances during the next solar eclipse (a hybrid annular-total crossing central Africa on November 3^rd, 2013) will be much more difficult, with a max totality located out to sea of only 1 minute and 40 seconds.

Libyan 2 — Mr. Noll talks with a local reporter during the 2006 total solar eclipse expedition to Libya. (Photograph courtesy of Landon Curt Noll, used with permission).

Still, we think it’s amazing that the quest for Vulcan (or at least Vulcanoids) is alive and well and being spearheaded by adventurous and innovative amateur astronomers. In the words of Vulcan’s native fictional son, may it “Live Long & Prosper!”

– For a fascinating read on the subject, check out In Search for planet Vulcan.

– Read more of Mr. Noll’s fascinating search for Vulcanoids here.

July 26, 2013April 26, 2016 by David Dickinson

Watch for the Delta Aquarid Meteors This Weekend

The Southern Delta Aquarid radiant, looking southeast at 2AM local from latitude 30 degrees north on the morning of July 30th. (Created by the author in Starry Night).

The meteor shower drought ends this weekend.

The northern summer hemisphere meteor season is almost upon us. In a few weeks’ time, the Perseids — the “Old Faithful” of meteor showers — will be gracing night skies worldwide.

But the Perseids have an “opening act”- a meteor shower optimized for southern hemisphere skies known as the Delta Aquarids.

This year offers a mixed bag for this shower. The Delta Aquarids are expected to peak on July 30^th and we should start seeing some action from this shower starting this weekend.

The Moon, however, also reaches Last Quarter phase the day before the expected peak of the Delta Aquarids this year on July 29^th at 1:43PM EDT/17:43 Universal Time (UT). This will diminish the visibility of all but the brightest meteors in the early morning hours of July 30^th.

A cluster of meteor shower radiants also lies nearby. The Eta Aquarids emanate from a point near the asterism known as the “Water Jar” in the constellation Aquarius around May 5^th. Another nearby but weaker shower known as the Alpha Capricornids are also currently active, with a zenithal hourly rate (ZHR) approaching the average hourly sporadic rate of 5. And speaking of which, the antihelion point, another source of sporadic meteors, is nearby in late July as well in eastern Capricornus.

The Delta Aquarids are caused by remnants of Comet 96P/Machholz colliding with Earth’s atmosphere. The short period comet was only discovered in 1986 by amateur astronomer Donald Machholz. Prior to this, the source of the Delta Aquarids was a mystery.

The Delta Aquarids have a moderate atmospheric entry velocity (for a meteor shower, that is) around an average of 41 kilometres a second. They also have one of the lowest r values of a major shower at 3.2, meaning that they produce a disproportionately higher number of fainter meteors, although occasional brighter fireballs are also associated with this shower.

Image of an early confirmed Delta Aquarid captured by the UK Fireball Network (@ on Twitter) captured by their Ash Vale North camera. — Image of an early confirmed Delta Aquarid by the UK Meteor Network (@UKMeteorNetwork on Twitter) captured by their Ash Vale North camera on July 17th, 2013. (Credit: Richard Kacerek & United Kingdom Meteor Observation Network, used with permission).

The Delta Aquarids are also one the very few showers with a southern hemisphere radiant. It’s somewhat of a mystery as to why meteor showers seem to favor the northern hemisphere. Of the 18 major annual meteor showers, only four occur below the ecliptic plane and three (the Alpha Capricornids, and the Eta and Delta Aquarids) approach the Earth from south of the equator. A statistical fluke, or just the product of the current epoch?

In fact, the Delta Aquarids have the most southern radiant of any major shower, with a radiant located just north of the bright star Fomalhaut in the constellation Piscis Austrinus near Right Ascension 339 degrees and Declination -17 degrees. Researchers have even broken this shower down into two distinct northern and southern radiants, although it’s the southern radiant that is the more active during the July season.

Together, this loose grouping of meteor shower radiants in the vicinity is known as the Aquarid-Capricornid complex. The Delta Aquarids are active from July 14^th to August 18^th, and unlike most showers, have a very broad peak. This is why you’ll see sites often quote the maximum for the shower at anywhere from July 28^th to the 31^st. In fact, you may just catch a stray Delta Aquarid while on vigil for the Perseids in a few weeks!

The shower was first identified by astronomer G.L. Tupman, who plotted 65 meteors associated with the stream in 1870. Observations of the Delta Aquarids were an off-and-on affair throughout the early 20^th century, with many charts erroneously listing them as the “Beta Piscids”. The separate northern and southern radiants weren’t even untangled until 1950. The advent of radio astronomy made more refined observations of the Delta Aquarids possible. In 1949, Canadian astronomer D.W.R. McKinley based out of Ottawa, Canada identified both streams and pinned down the 41 km per second velocity that’s still quoted for the shower today.

Further radio studies of the shower were carried out at Jodrell Bank in the early 1950’s, and the shower gave strong returns in the early 1970’s for southern hemisphere observers even with the Moon above the horizon, with ZHRs approaching 40. The best return for the Southern Delta Aquarids in recent times is listed by the International Meteor Organization as a ZHR of about 40 on the morning of July 28^th, 2009.

A study of the Delta Aquarids in 1963 by Fred Whipple and S.E. Hamid reveal striking similarities between the Delta Aquarids and the January Quadrantids & daytime Arietid stream active in June. They note that the orbital parameters of the streams were similar about 1,400 years ago, and the paths are thought to have diverged due to perturbations from the planet Jupiter.

Observing the Delta Aquarids can serve as a great “dry run” for the Perseids in a few weeks. You don’t need any specialized gear, simply find a dark site, block the Moon behind a building or hill, and watch.

Photographing meteors is similar to doing long exposures of star trails. Simply aim your tripod mounted DSLR camera at a section of sky and take a series of time exposures about 1-3 minutes long to reveal meteor streaks. Images of Delta Aquarids seem elusive, almost to the point of being mythical. An internet search turns up more blurry pictures of guys in ape suits purporting to be Bigfoot than Delta Aquarid images… perhaps we can document the “legendary Delta Aquarids” this year?

– Read more of the fascinating history of the Delta Aquarids here.

– Seen a meteor? Be sure to tweet it to #Meteorwatch.

– The IMO wants your meteor counts and observations!

July 24, 2013December 23, 2015 by David Dickinson

Near-Earth Asteroid 2003 DZ15 to Pass Earth Monday Night

The currnet orbital position of asteroid 2003 DZ15. (Created by the author using JPL's Small-Body Database Browser).

The Earth will get another close shave Monday, when the 152 metre asteroid 2003 DZ15 makes a pass by our fair planet on the night of July 29^th/30^th at 3.5 million kilometres distant. This is over 9 times the Earth-Moon distance and poses no threat to our world.

This is much smaller than 2.75 kilometre 1998 QE2, which sailed by (bad pun intended) our fair world at 5.8 million kilometres distant on May 31st, 2013. The Virtual Telescope Project will be presenting a free online event to monitor the passage of NEA 2003 DZ15 starting Monday night July 29^th at 22:00 UT/6:00 PM EDT.

As of this writing, no efforts are currently known of by professional observatories to monitor its passage via radar, though Arecibo may attempt to ping 2003 DZ15 on Thursday.

An Apollo asteroid, 2003 DZ15 was confirmed by the Lowell Observatory and NEAT’s Mount Palomar telescope upon discovery in February 2003. This is its closest approach to the Earth for this century, although it will make a pass nearly as close to the Earth in 2057 on February 12^th.

With a perihelion (closest approach to the Sun of) 0.63 A.U.s, 2003 DZ15 can also make close passes by the planet Venus as well, which it last did in 1988 and will do again on 2056.

Closest approach of 2003 DZ15 is set for 00:37 UT July 30^th, or 8:37 PM EDT the evening of Monday, July 29^th. Although it will only reach about +14th magnitude (based on an absolute magnitude of +22.2), and hence be out of range to all but the very largest Earthbound backyard telescopes, it’ll be fun to watch as it slowly drifts across the starry background live on the internet. Our own, “is worth tracking down from our own backyard” limit is an asteroid passing closer than our Moon, or is farther, but is brighter than +10^th magnitude… such are the limitations of humid Florida skies!

Of course, an asteroid the size of 2003 DZ15 would spell a bad day for the Earth, were it headed our way. At an estimated 152 metres in size, 2003 DZ is over seven times the size of the Chelyabinsk meteor that exploded over Russia the day after Valentine ’s on February 15^th of this year. While not in the class of an Extinction Level event, 2003 DZ15 would be in 60 to 190 metre size of range of the Tunguska impactor that struck Siberia in 1908.

All enough for us to take notice as 2003 DZ15 whizzes by, at a safe distance this time. NASA plans to launch a crewed mission sometime over the next decade to study an asteroid, and perhaps retrieve a small NEA and place it in orbit about Earth’s Moon. Such efforts may go a long way in understanding and dealing with such potentially hazardous space rocks, when and if the “big one” is discovered heading our way. We’re the Earth’s first line of defense- and unlike the ill-fated dinosaurs, WE’VE got a space program and can do something about it!

July 16, 2013December 23, 2015 by David Dickinson

Seeing Red: Hunting Herschel’s Garnet Star

Mu Cephei (arrowed) in the constellation Cepheus the King. (Photo & graphic by author).

Quick, what’s the reddest star visible to the naked eye?

Depending on your sky conditions, your answer may well be this week’s astronomical highlight.

Mu Cephei, also known as Herschel’s Garnet Star, is a ruddy gem in the constellation Cepheus near the Cygnus/Lacerta border. A variable star ranging in brightness by a factor of about three-fold from magnitudes 5.0 to 3.7, Mu Cephei is low to the northeast for mid-northern latitude observers in July at dusk, and will be progressively higher as summer wears on. Continue reading “Seeing Red: Hunting Herschel’s Garnet Star”

July 11, 2013April 26, 2016 by David Dickinson

How to Spot and Track Satellites

A 10 second exposure of a bright pass of the International Space Station. (Photo by Author).

It’s a question we get all the time.

Watch the sky closely in the dawn or dusk hours, and you’ll likely see a moving “star” or two sliding by. These are satellites, or “artificial moons” placed in low Earth orbit. These shine via reflected sunlight as they pass hundreds of kilometres overhead.

Many folks are unaware that you can see satellites with the naked eye. I always make an effort to watch for these during public star parties and point them out. A bright pass of the International Space Station if often as memorable as anything that can be seen through the eyepiece. But after this revelation, “the question” soon follows- “What satellite is that?”

Welcome to the wonderful and highly addictive world of satellite tracking. Ground observers have been watching the skies since Sputnik 1 and the first satellite launch in October 1957. Armies of dedicated volunteers even participated in tracking the early launches of the Space Age with Operation Moonwatch.

Depiction of the apparent motion of a typical satellite overhead with respect to the observer. (Graphic created by author).

The Internet has offered a wealth of information for satellite hunters. Every time I write about “how to spot the ISS,” someone amazes me with yet another new tracker App that I hadn’t heard of. One of my favorites is still Heavens-Above. It’s strange to think that we’ve been visiting this outstanding website daily for a decade and a half now. Heavens-Above specializes in satellites, and will show you a quick listing of passes for brighter satellites once configured with your location. A nifty “quick check” for possibly resolving a mystery satellite is their link for “Daily Predictions for brighter satellites” Which will generate a list of visible passes by time.

Screenshot of a typical list of bright satellite passes from Heavens-Above. — Screenshot of a typical list of bright satellite passes from Heavens-Above filtered by brightness, time and location .

Looking at the time, direction, and brightness of a pass is crucial to satellite identification. No equipment is needed to start the hunt for satellites tonight, just a working set of eyes and information. We sometimes use a set of Canon image-stabilized 15x 45 binoculars to hunt for satellites too faint to see with the naked eye. We’ve seen the “Tool Bag” lost during an ISS EVA a few years back, as well as such “living relics” of the early Space Age as Canada’s first satellite Alloutte-1, and the Vanguards (Yes, they’re STILL up there!) using binocs.

A comparision of typical satellite orbits. (Credit — A comparison of typical satellite orbits. (Credit: Cmglee, Geo Swan graphic under a Creative Commons Attribution -Share Alike 3.0 unported license).

The trick to catching fainter satellites such as these is to “ambush” them. You’ll need to note the precise time that the selected satellite is going to pass near a bright star. Clicking on a selected satellite pass in Heavens-Above will give you a local sky chart with a time-marked path. I use a short wave portable AM radio tuned to WWV out of Fort Collins, Colorado for an accurate audible time signal. Just sit back, listen to the radio call out the time, and watch for the satellite to pass through the field of view near the target star.

Another great site for more advanced trackers is CALSky. Like Heavens-Above, CALSky will give you a customized list for satellite passes over your location. One cool extra feature on CALSky is the ability to set alerts for passes of the ISS near bright planets or transiting the Sun or Moon. These are difficult events to capture, but worth it!

The International Space Station transiting the Moon as captured by Mike Weasner from Cassiopeia Observatory in Arizona.

A great deal of what’s up there is space junk in the form of discarded hardware. Many satellites are on looping elliptical orbits, only visible to the naked eye when they are near perigee. Many satellites are located out at geosynchronous or geostationary orbits 35,786 kilometres distant and are invisible to the naked eye all together. These will often show up as streaks in astrophotos. An area notorious for geosynchronous satellites exists near the direction of M42 or Orion Nebula. During certain times of year, satellites can be seen nearby, nodding slowly north to south and back again. Around the March and September equinox seasons, geostationary satellites can be eclipsed by the shadow of the Earth. This can also cause communications difficulties, as many geo-sats also lie sunward as seen from the Earth around these times of year.

Probably one of the simplest satellite trackers for casual users is Space Weather’s Satellite Flybys page. North American users simply need to enter a postal code (worldwide users can track satellites via entering “country-state-city”) and a list of passes for your location is generated.

It’s a basic truism of satellite tracking that “aircraft blink; satellites don’t”. Know, we’re going to present an exception to this rule.

Some satellites will flash rhythmically due to a tumbling motion. This can be pretty dramatic to see. What you’re seeing is an expended booster, a cylinder tumbling due to atmospheric drag end-over-end. Some satellites can flash or flare briefly due to sunlight glinting off of reflective surfaces just right. Hubble, the ISS and the late NanoSail D2 can flare if conditions are just right.

The most dramatic of these are Iridium flares. The Iridium constellation consists of 66 active satellites used for satellite phone coverage in low-Earth orbit. When one of their three refrigerator-sized antennas catch the Sun just right, they can flare up to magnitude -8, or 40 times brighter than Venus. CALSky and Heavens-Above will also predict these events for your location.

Didn’t see a predicted satellite pass? Light pollution or bright twilight skies might be to blame. Keep in mind, passes lower to the horizon also fall prey to atmospheric extinction, as you’re looking through a thicker layer of the air than straight overhead. Some satellites such as the ISS or the USAF’s X-37B spy space plane even periodically boost or modify their orbits, throwing online prediction platforms off for a time.

More advanced satellite trackers will want to check out Celestrak and SAT-Flare Tracker 3D.

A screenshot example of TLE's for the ISS & Tiangong-1 from Celestrak. — A screenshot example of TLE’s for the ISS & Tiangong-1 from Celestrak.

I use a free tracking platform created by Sebastian Stoff known as Orbitron. Orbitron lets you set your observing location and tailor your view for what’s currently over head. You can run simulations and even filter for “visual only” passes, another plus. I also like Orbitron’s ability to run as a stand-alone system in the field, sans Internet connection. Just remember, for it to work properly, you’ll need to periodically update the .txt file containing the Two-Line Element (TLE) sets. TLE’s are data element sets that describe the orbital elements of a satellite. Cut and paste TLEs are available from Heavens-Above and Celestrak.

Orbitron screenshot for visible satellites using 'radar' mode... there's lots up there! (Credit: Orbitron). — Orbitron screenshot for visible satellites using ‘radar’ mode… there’s lots up there! (Credit: Orbitron).

For serious users, NORAD’s Space-Track is the best site for up-to-date TLEs. Space-Track requires a login and user agreement to access, but is available to satellite spotters and educators as a valuable resource. Space-Track also hosts a table of upcoming reentries, as does the Aerospace Corporation’s Center for Orbital & Reentry Debris Studies.

The SeeSat-L mailing list is also an excellent source of discussion among satellite trackers worldwide. Increasingly, this discussion is also moving over to Twitter, which is ideal for following swiftly evolving action in orbit. @Twisst, created by Jaap Meijers,will even Tweet you prior to an ISS pass!

And there’s always something new or strange in the sky for the observant. Satellites such as those used in the Naval Ocean Surveillance System (NOSS) were launched in groups, and are eerie to watch as they move in formations of 2 or 3 across the sky. These are difficult to catch, and all three of our sightings thus far of a NOSS pair have been surreptitious. And we’ve only had the camera ready to swing into action once to nab a NOSS pair;

A NOSS pair captured by the author. The multi-colored trail bisecting the path is an aircraft. Note a bit of "jitter" at the beginning of the exposure- I had to swing the camera into action quickly! — A NOSS pair captured by the author. The multi-colored trail to the left of the path is an aircraft. Note a bit of “jitter” at the beginning of the exposure- I had to swing the camera into action quickly!

Another bizarre satellite to catch in action is known as the Cloud-Aerosol LiDAR & Infrared Pathfinder Satellite for Observations, or CALIPSO. Part of the “afternoon A-Train” of sun-synchronous Earth observing satellites, you can catch the green LiDAR flashes of CALIPSO from the ground with careful planning, just as Gregg Hendry did in 2008-2009:

A CALIPSO LIDAR pass imaged by Gregg Hendry in 2008. My Hendry mentions that, "The hollow nature of the spots is likely due to some spherical aberration in the camera lens coupled with imperfect focus and is not representative of the laser beam's optical quality." — A CALIPSO LiDAR pass imaged by Gregg Hendry in 2008. My Hendry mentions that, “The hollow nature of the spots is likely due to some spherical aberration in the camera lens coupled with imperfect focus, and is not representative of the laser beam’s optical quality.” (Credit: Gregg Hendry, used with permission).

NASA even publishes a prediction table for CALIPSO lidar passes. I wonder how many UFO sightings CALIPSO has generated?

Artist's depiction of the A-Train constellation of Earth-Observing satellites. (Credit: NASA). — Artist’s depiction of the A-Train constellation of Earth-Observing satellites. (Credit: NASA).

And speaking of photography, it’s easy to catch a bright pass such as the ISS on camera. Shooting a satellite pass with a wide field is similar to shooting star trails; just leave the shutter open for 10-60 seconds with a tripod mounted camera. Modern DSLRs allow you to do several test exposures prior to the pass, to get the ISO, f/stop, and shutter speed calibrated to local sky conditions.

You can even image the ISS through a telescope. Several sophisticated rigs exist to accurately track and image the space station through a scope, or you could use our decidedly low-tech but effective hand-guided method;

And that’s a brief overview of the exciting world of sat-spotting… let us know of your tales of triumph and tragedy as you sleuth out what’s going on overhead!

July 8, 2013April 26, 2016 by David Dickinson

Conjunctions to Watch For in July

The waxing crescent Moon joins the evening sky early this week. (Photo by author).

The planets are slowly returning into view this month, bashfully peeking out from behind the Sun in the dawn & dusk sky. This month offers a bonanza of photogenic conjunctions, involving the Moon, planets and bright stars.

The action begins tonight on July 8^th, as the waxing crescent Moon joins the planet Venus in the dusk sky. The razor thin Moon will be a challenge on Monday night, as it just passed New on the morning of the 8^th at 3:14AM EDT/7:14 Universal Time (UT). The record for spotting the thin crescent with the naked eye currently stands at 15 hours and 32 minutes, completed by Stephen O’Meara on May 1990. Binoculars help considerably in this endeavor. Wait until 15 minutes after local sunset, and then begin patiently sweeping the horizon.

Mr. Thierry Legault completed an ultimate photographic challenge earlier today, capturing the Moon at the precise moment of New phase!

The Moon & Venus on the evening of July 9th from latitude 30 degrees north, about 30 minutes after sunset. (Created by the author using Stellarium). — The Moon & Venus on the evening of July 9th as seen from latitude 30 degrees north, about 30 minutes after sunset. (Created by the author using Stellarium).

This week marks the start of lunation 1120. The Moon will be much easier to nab for observers worldwide on Tuesday night, July 9^th for observers worldwide. The sighting of the waxing crescent Moon will also mark the start of the Muslim month of Ramadan for 2013. Due to the angle of the ecliptic in July, many northern hemisphere observers may not spot the Moon until Wednesday night on July 10^th, about 6.7 degrees south west of -4.0 magnitude Venus.

Did you know? There are Guidelines for the Performance of Islamic Rites for Muslims aboard the International Space Station. It’s interesting to note that the timing of the rituals follows the point from which the astronaut originally embarked from the Earth, which is exclusively the Baikonur Cosmodrome in Kazakhstan for the foreseeable future of manned spaceflight.

Malaysia’s first astronaut, Sheikh Muszaphar Shukor observed Ramadan aboard the International Space Station in 2007.

From there, the crescent Moon fattens, meeting up with Saturn and Spica on the evenings of July 15^th and 16^th. The Moon will actually occult (pass in front of) the bright star Spica on the evening of July 15/16^th at ~3:33UT/11:33PM EDT (on the 15^th) for observers in Central America and western South America. The rest of us will see a near miss worldwide.

The waxing crescent Moon nearing Spica on the evening of the 15th at 10PM EDT. The Moon reaches 1st Quarter on the same evening at 11:18PM EDT. (Created by the author using Starry Night). — The waxing crescent Moon nearing Spica on the evening of the 15th at 10PM EDT. The Moon reaches 1st Quarter phase on the same evening at 11:18PM EDT. (Created by the author using Starry Night).

This is the 13th in a cycle of 18 occultations of Spica by our Moon spanning 2012-2013. Spica is one of four stars brighter than magnitude +1.4 that lie close enough to the ecliptic to be occulted by our Moon, the others being Antares, Regulus and Aldebaran. Saturn will lie 3 degrees from the Moon on the evening of July 16^th.

Can you nab Spica and Saturn near the Moon with binoculars in the daytime around the 15^th? It can be done, using the afternoon daytime Moon as a guide. Crystal clear skies (a rarity in the northern hemisphere summertime, I know) and physically blocking the Sun behind a building or hill helps.

The waxing gibbous Moon will also occult +2.8 Alpha Librae for South Africa on July 17^th around 17:09UT & +4.4^th magnitude Xi Ophiuchi for much of North America on the night of July 19^th-20^th.

And speaking of Regulus, the brightest star in the constellation Leo lies only a little over a degree (two Full Moon diameters) from Venus only the evenings of July 21^st & the 22^nd. 77.5 light years distant, Regulus is currently over 100 times fainter at magnitude +1.4. Can you squeeze both into the field of view of your telescope at low power? Venus’s mythical ‘moon’ Neith lives!

Venus can even occult Regulus on rare occasions, as last occurred on July 7th, 1959 and will happen next on October 1st, 2044.

But there’s morning action afoot as well. The planets Mars and Jupiter have emerged from solar conjunction on April 18th and June 19th, 2013 respectively, and can now be seen low in the dawn skies about 30 minutes before sunrise.

Mars and Jupiter in a close conjunction on the morning of July 22nd, about 30 minutes before sunrise as seen from latitude 30 degrees north. (Created by the author using Starry Night).

Mars approaches Jupiter in the dawn until the pair is only 0.79 degrees (about 48 arc minutes) apart on Monday, July 22^nd. Mars shines at magnitude +1.6 and shows a tiny 3.9” disk, while Jupiter displays a 32.5” disk shining at magnitude -1.9 on this date. Conjunction occurs at about 7:00 UT/3:00 AM EDT, after which the two will begin to race apart. Mercury is visible beginning its morning apparition over 5 degrees to the lower right of the pair (see above).

Jupiter will reach opposition and reenter the evening sky on January 5th, 2014, while Mars won’t do the same until April 8th of next year. Weird factoid alert: neither Jupiter or Mars reach opposition in 2013! What effect does this have on terrestrial affairs? Absolutely none, well unless you’re a planetary imager/observer…

Mars also reaches its most northern declination of 2013 of 24 degrees in the constellation Gemini on July 16^th at 7:00 AM EDT/11:00 UT. Mars can wander as far as declination 27 degrees north, as last happened in 1993.

Finally, are you observing from southern Mexico this week and up for a true challenge? The asteroid 238 Hypatia occults a +7.4 magnitude star from 10:13-10:49 UT on July 10^th in the constellation Pisces for up to 29 seconds. This event will be bright enough to watch with binoculars- check out our best prospects for asteroid occultations of stars in 2013 here and here.

Good luck, clear skies, and be sure to post those astro-pics in the Universe Today’s Flickr community!

July 3, 2013December 23, 2015 by Bob King

What You Can See in the Sky While Waiting for Fireworks on The 4th Of July

A thin lunar crescent rises beneath the Pleiades star cluster tomorrow morning at dawn. This map shows the sky facing northeast about 4 a.m. local time. Maps created with Stellarium

The sky can be a showy stage with big-time events like eclipses, meteor showers and the occasional bright comet, but most nights have a quiet beauty that whispers instead of shouts. The contrast between hype and hush is no more apparent than on the 4th of July – American independence day celebration – when we gather at a park or hilltop to watch the fireworks boom and flash across the heavens.

But there are other interesting things — some quiet fireworks — you can see in the sky to see while you are waiting for the holiday fireworks.

You can watch a less flashy but equally satisfying July 4th event as soon as tomorrow morning about the time the first bird lifts its voice at dawn. Look northeast to find a thin crescent moon dangling below the Seven Sisters star cluster. Also called the Pleiades, the cluster is a highlight of the winter evening sky. Though it seems out of place now at the height of summer, the Sisters remind us that nothing stands still. With the solstice behind us, winter’s already buckling his boots.

As you relax before the fireworks begin, look for two bright stars and two bright planets in the west and southwest skies. You can fit about three fists held at arm's length between Saturn and Arcturus. — As you relax before the fireworks begin, look for two bright stars and two bright planets in the west and southwest skies. You can fit about three fists held at arm’s length between Saturn and Arcturus.

While you’re waiting for the show to begin tomorrow night, take a look around the twilight sky and see how many celestial luminaries you can spot. If you’ve got kids in tow, share the view with them, too.

The brightest natural object in the sky will be Venus, glimmering low above the western horizon. Much further up in the southwest, look for a tall, skinny triangle outlined by orangy Arcturus, highest of the three, along with Saturn and Spica.

*Facing east brings the three bright stars of the Summer Triangle in to view.*

Twist around to face east to find another triangle, this one named after the summer season. Halfway up is Vega, the 5th brightest star in the sky, shining white and bright as burning magnesium. Below it you’ll spot the other Summer Triangle members, Altair in Aquila the Eagle and Deneb in Cygnus the Swan better known as the Northern Cross.

These bright stars and two planets coalesced from gas and dust millions to billions of years ago. Much has happened beneath their gaze, from the first stirrings of humankind to the crackle and boom of fireworks on a starry evening.

July 2, 2013April 26, 2016 by Bob King

Dark Skies – Good For Fireflies And People Alike

Fireflies make green trails of light during a time exposure on a July night. Jupiter is at upper left. Credit: Bob King

Bioluminescent stars flash across the night landscape these July nights. Fireflies or lightning bugs provide a source of wonder for many of us living in the eastern half U.S. and Canada. Did you know dark skies may be as important to them as they are to you and I?

To stoke their yellow-green fires, the bugs – they’re really beetles – cook up light through a series of chemical reactions within their abdomens.

Adult Photurus firefly. Fireflies produce a cool light by combining oxygen in the air with the chemical luciferin. Credit: Bruce Marlin

Oxygen from the air combines with a chemical fittingly named luciferin. Luciferin next hooks up with the energy molecule ATP to form another molecule that when combined with oxygen yields a flash of green, yellow or amber light, depending upon the firefly species.

Fireflies June 30 2013 C — Fireflies compete with the stars from a dark location near Duluth, Minn. two nights ago. Each species has its own specific flash pattern. Credit: Bob King

The males perform the flash-dance moves, wiggling and zigging about to attract the females, who typically remain on the ground hidden among blades of grass. Each species has its own flashing pattern. When a female finds a male’s flashes suitably alluring, she winks a flash back. Back and forth communications soon bring the two together to make more fireflies.

Firefly light emits no heat, making it one of the most efficient light sources known. A standard incandescent light bulb converts electricity into 10% light and the rest as heat; fireflies transform 100% of their chemical energy into light. These insects do not waste photons.

One of my favorite memories from childhood was running around on summer nights collecting fireflies in a glass jar. Credit: Bob King

Every night I’m out under the July stars at least one firefly manages to land within the telescope tube and create a surprise supernova. If I inadvertently switch my LED flashlight on and off at the right rate, more than a few of them will land right on top of the device in a futile attempt to mate.

Urban sprawl and accompanying light pollution is an issue for both astronomers and fireflies. This view shows the light dome from the city of Duluth, Minn. 20 miles north of town. Credit: Bob King

One thing fireflies and skywatchers have in common is love of the night. To appreciate the twinkling heavens, we either escape to the countryside or do our best to contend with the lights in town. Firefly numbers are declining across the U.S. and the world, and though no one’s certain yet why, there’s both anecdotal and scientific evidence suggesting that loss of habitat and light pollution are to blame.

Example showing poorly shielded light fixtures. With nothing to contain or direct the light, it shines where it's not needed - straight up! Credit: Bob King — Example showing poorly shielded light fixtures. With nothing to contain or direct the light, it shines where it’s not needed – straight up! Credit: Bob King

Urban sprawl has comprised the habitats of many wild creatures not just fireflies. Sprawl also brings increased lighting, much of it poorly shielded and on all night. Fireflies avoid heavily lit areas for obvious reasons – light pollution interferes with their ability to see each others’ flashes. Even car headlights can throw them off rhythm. According to a 2008 story in the Boston Globe, controlled experiments have shown that brighter lighting levels cause fireflies to mate less often.

Full cutoff lighting fixtures like these put light where it's needed - on the road - and not out to the sides or up in the sky. Credit: Bob King — Full cutoff lighting fixtures like these put light where it’s needed – on the road – and not out to the sides or up in the sky. Credit: Bob King

We all can help ensure our favorite bioluminescent buddies remain around for a long time. Turning off your own yard light not only helps you to see more stars but makes it easier for fireflies to find their mates. If you absolutely need illumination, consider one of these efficient shielded light fixtures that puts light where you want it while eliminating the glare that frustrates fireflies and stargazers alike. To learn more about good lighting and keeping the sky dark, check out the International Dark Sky Association.

July 2, 2013December 23, 2015 by David Dickinson

Happy (or is it Merry?) Aphelion This Friday

Solar apparent size- perihelion versus aphelion 2012.

This 4^th of July weekend brings us one more reason to celebrate. On July 5^that approximately 11:00 AM EDT/15:00 UT, our fair planet Earth reaches aphelion, or its farthest point from the Sun at 1.0167 Astronomical Units (A.U.s) or 152,096,000 kilometres distant.

Though it may not seem it to northern hemisphere residents sizzling in the summer heat, we’re currently 3.3% farther from the Sun than our 147,098,290 kilometre (0.9833 A.U.) approach made in early January.

We thought it would be a fun project to capture this change. A common cry heard from denier circles as to scientific facts is “yeah, but have you ever SEEN it?” and in the case of the variation in distance between the Sun and the Earth from aphelion to perihelion, we can report that we have!

We typically observe the Sun in white light and hydrogen alpha using a standard rig and a Coronado Personal Solar Telescope on every clear day. We have two filtered rigs for white light- a glass Orion filter for our 8-inch Schmidt-Cassegrain, and a homemade Baader solar filter for our DSLR. We prefer the DSLR rig for ease of deployment. We’ve described in a previous post how to make a safe and effective solar observing rig using Baader solar film.

Our solar imaging rig. — Our primary solar imaging rig. A Nikon D60 DSLR with a 400mm lens + a 2x teleconverter and Baader solar filter. Very easy to employ!

We’ve been imaging the Sun daily for a few years as part of our effort to make a home-brewed “solar rotation and activity movie” of the entire solar cycle. We recently realized that we’ve imaged Sol very near aphelion and perihelion on previous years with this same fixed rig, and decided to check and see if we caught the apparent size variation of our nearest star. And sure enough, comparing the sizes of the two disks revealed a tiny but consistent variation.

It’s a common misconception that the seasons are due to our distance from the Sun. The insolation due to the 23.4° tilt of the rotational axis of the Earth is the dominant driving factor behind the seasons. (Don’t they still teach this in grade school? You’d be surprised at the things I’ve heard!) In the current epoch, a January perihelion and a July aphelion results in milder climatic summers in the northern hemisphere and more severe summers in the southern. The current difference in solar isolation between hemispheres due to eccentricity of Earth’s orbit is 6.8%.

The orbit of the Earth also currently has one of the lowest eccentricities (how far it deviates for circular) of the planets at 0.0167, or 1.67%. Only Neptune (1%) and Venus (0.68%) are “more circular.”

The orbital eccentricity of the Earth also oscillates over a 413,000 year period between 5.8% (about the same as Saturn) down to 0.5%. We’re currently at the low end of the scale, just below the mean value of 2.8%.

Variation in eccentricity is also coupled with other factors, such as the change in axial obliquity the precession of the line of apsides and the equinoxes to result in what are known as Milankovitch cycles. These variations in extremes play a role in the riddle of climate over hundreds of thousands of years. Climate change deniers like to point out that there are large natural cycles in the records, and they’re right – but in the wrong direction. Note that looking solely at variations in the climate due to Milankovitch cycles, we should be in a cooling trend right now. Against this backdrop, the signal of anthropogenic climate forcing and global dimming of albedo (which also masks warming via cloud cover and reflectivity) becomes even more ominous.

Aphelion can presently fall between July 2^nd at 20:00 UT (as it did last in 1960) and July 7^that 00:00 UT as it last did on 2007. The seemingly random variation is due to the position of the Earth with respect to the barycenter of the Earth-Moon system near the time of aphelion. The once every four year reset of the leap year (with the exception of the year 2000!) also plays a lesser role.

Perihelion and aphelion vs the solstices and equinoxes, an exagarated view. — Perihelion and aphelion vs the solstices and equinoxes, an exaggerated view. (Wikimedia Commons image under a 3.0 Unported Attribution-Share Alike license. Author Gothika/Doudoudou).

I love observing the Sun any time of year, as its face is constantly changing from day-to-day. There’s also no worrying about light pollution in the solar observing world, though we’ve noticed turbulence aloft (in the form of bad seeing) is an issue later in the day, especially in the summertime. The rotational axis of the Sun is also tipped by about 7.25° relative to the ecliptic, and will present its north pole at maximum tilt towards us on September 8th. And yes, it does seem strange to think in terms of “the north pole of the Sun…”

We’re also approaching the solar maximum through the 2013-2014 time frame, another reason to break out those solar scopes. This current Solar Cycle #24 has been off to a sputtering start, with the Sun active one week, and quiet the next. The last 2009 minimum was the quietest in a century, and there’s speculation that Cycle #25 may be missing all together.

And yes, the Moon also varies in its apparent size throughout its orbit as well, as hyped during last month’s perigee or Super Moon. Keep those posts handy- we’ve got one more Super Moon to endure this month on July 22^nd. The New Moon on July 8^th at 7:15UT/3:15 AM EDT will occur just 30 hours after apogee, and will hence be the “smallest New Moon” of 2013, with a lot less fanfare. Observers worldwide also have a shot at catching the slender crescent Moon on the evening of July 9^th. This lunation and the sighting of the crescent Moon also marks the start of the month of Ramadan on the Muslim calendar.

Be sure to observe the aphelion Sun (with proper protection of course!) It would be uber-cool to see a stitched together animation of the Sun “growing & shrinking” from aphelion to perihelion and back. We could also use a hip Internet-ready meme for the perihelion & aphelion Sun- perhaps a “MiniSol?” A recent pun from Dr Marco Langbroek laid claim to the moniker of “#SuperSun;” in time for next January’s perihelion;

Could a new trend be afoot?