transit Archives

October 6, 2014December 23, 2015 by Nancy Atkinson

Watch the Space Station Zip Across the Sun: Incredible New Views from Thierry Legault

Stacked images of a solar transit of the International Space Station in September, 2014. Total transit time is .7 seconds. Credit and copyright: Thierry Legault.

Take a look at the incredible detail in the latest work from astrophotographer extraordinaire Thierry Legault. He captured images of the International Space Station transiting in front of the Sun in September 2014, and visible in the images are several of the visiting docked spacecraft (at one point in September there were 5 ships parked at the Station). Clearly visible are the ATV-5 ‘Georges Lemaitre,’ the Soyuz 39 and the Progress 56.

Wow!

Keep in mind, an ISS transit lasts less than a second (.7 seconds to be exact — and is shown in real time in the video above) and capturing the event in images must be timed with ultimate precision. Legault has captured a detailed night passage of the ISS, as well. See images below.

Legault used his Celestron C14 EdgeHD to capture these images, and for the solar transit of ISS, he used both both H-alpha and white light filters.

In a previous Universe Today article, Legault explained how he studies maps, and will travel thousands of kilometers to be in the right place to capture such a transit. He uses a radio synchronized watch to know very accurately when the transit event will happen.

His camera has a continuous shuttering for 4 seconds, and he begins the imaging sequence 2 seconds before the calculated time.

“For transits I have to calculate the place, and considering the width of the visibility path is usually between 5-10 kilometers, but I have to be close to the center of this path,” Legault explained, “because if I am at the edge, it is just like a solar eclipse where the transit is shorter and shorter. And the edge of visibility line of the transit lasts very short. So the precision of where I have to be is within one kilometer.”

Solar transit of the International Space Station with the ATV-5 'Georges Lemaitre' docked, in September 2014. Credit and copyright: Thierry Legault. — Solar transit of the International Space Station with the ATV-5 ‘Georges Lemaitre’ docked, in September 2014. Credit and copyright: Thierry Legault.

See more images and information at Thierry’s website, and we thank him for sharing his work with Universe Today.

Detailed imagery of the International Space Station captured from the ground. Credit and copyright: Thierry Legault.

June 10, 2014December 23, 2015 by Jason Major

Curiosity Captures Mercury from Mars

Image of the Sun as seen from Mars by Curiosity. Mercury is the circled dark spot.

NASA’s Curiosity rover may be busy exploring the rugged and rocky interior of Gale Crater, but it does get a chance to skygaze on occasion. And while looking at the Sun on June 3, 2014 (mission Sol 649) the rover’s Mastcam spotted another member of our Solar System: tiny Mercury, flitting across the Sun’s face.

Silhouetted against the bright disk of the Sun, Mercury barely appears as a hazy blur in the filtered Mastcam images. But it was moving relatively quickly during the transit, passing the darker smudges of two Earth-sized sunspots over the course of several hours.

It’s the first time Mercury has ever been imaged from Mars, and also the first time we’ve observed a planet transiting our Sun from another world besides our own.

Watch an animation of the transit below:

Animated blink comparison showing Mercury's movement across the Sun — Animated 1-hour interval blink comparison showing Mercury’s movement across the Sun

Because the sunspots move along with the rotation of the Sun (and the Sun rotates once avery 25 days around its equator) Mercury makes a fast pass as it travels along on one of its 88-day-long years.

Watch an HD version of the event here.

In reality this was no chance spotting, but rather a carefully calculated observation using the Mastcam’s right 100mm telephoto lens and neutral density filter, which is used to routinely image the Sun in order to measure the dustiness of the Martian atmosphere.

“This is a nod to the relevance of planetary transits to the history of astronomy on Earth. Observations of Venus transits were used to measure the size of the solar system, and Mercury transits were used to measure the size of the sun.”

– Mark Lemmon, Texas A&M University, member of the Mastcan science team

The next chance for Curiosity to spot Mercury will come in April 2015 and, if the rover is still operating by then — perhaps with some upgrades by future human visitors? — it may capture Earth similarly passing across the Sun in November of 2084.

Source: NASA/JPL

Image/animation credit: NASA/JPL-Caltech/MSSS/Texas A&M

May 9, 2014December 23, 2015 by Bob King

Observing Alert: See Mercury’s Best Evening Show of the Year

Mercury starts its best period of visibility in the evening sky for skywatchers at mid-northern latitudes this weekend. This map shows the sky facing northwest about 40 minutes after sundown. Bright Jupiter also provides a convenient sightline for locating Mercury. Stellarium

Don’t let furtive Mercury slip through your fingers this spring. The next two and a half weeks will be the best time this year for observers north of the tropics to spot the sun-hugging planet. If you’ve never seen Mercury, you might be surprised how bright it can be. This is especially true early in its apparition when the planet looks like a miniature ‘full moon’.

Mercury, like Venus, displays phases as it revolves around the sun as seen from Earth's perspective outside Mercury's orbit. Credit: Bob King — Mercury, like Venus, displays phases as it revolves around the sun as seen from Earth’s perspective outside Mercury’s orbit. Both Mercury and Venus appear largest when nearly lined up between Earth and sun at inferior conjunction. Planets not to scale and phases shown are approximate. Credit: Bob King

Both Venus and Mercury pass through phases identical to those of the moon. When between us and the sun, Mercury’s a thin crescent, when off to one side, a ‘half-moon’ and when on the far side of the sun, a full moon. This apparition of the planet is excellent because Mercury’s path it steeply tilted to the horizon in mid-spring.

We start the weekend with Mercury nearly full and brighter than the star Arcturus. Twilight tempers its radiance, but :

* Find a location with a wide open view to the northwest as far down to the horizon as possible.

* Click HERE to get your sunset time and begin looking for the planet about 30-40 minutes after sunset in the direction of the sunset afterglow.

* Reach your arm out to the northwestern horizon and look a little more than one vertically-held fist (10-12 degrees) above it for a singular, star-like object. Found it? Congratulations – that’s Mercury!

* No luck? Start with binoculars instead and sweep the bright sunset glow until you find Mercury. Once you know exactly where to look, lower the binoculars from your eyes and you should see the planet without optical aid. And before I forget – be sure to focus the binoculars on a distant object like a cloud or the moon before beginning your sweeps. I guarantee you won’t find Mercury if it’s out of focus.

Through a telescope, Mercury looks like a gibbous moon right now but its phase will lessen as it moves farther to the ‘left’ or east of the sun. Greatest eastern elongation happens on May 24. On and around that date the planet will be farthest from the sun, standing 12-14 degrees high 40 minutes after sundown from most mid-northern locales.

jjjjjjj — Mercury is even better placed on May 19 but fades and begins to drop back down toward the horizon late in the month. Stellarium

The planet fades in late May and become difficult to see by early June. Inferior conjunction, when Mercury passes between the Earth and sun, occurs on June 19. Unlike Venus, which remains brilliant right up through its crescent phase, Mercury loses so much reflective surface area as a crescent that it fades to magnitude +3. Its greater distance from Earth, lack of reflective clouds and smaller size can’t compete with closer, brighter and bigger Venus.

Mercury's path across the solar disk as seen from the Solar and Heliospheric Observatory (SOHO) on November 8, 2006. The transit was visible in eastern Europe and the eastern hemisphere. Credit: NASA. — When a planet crosses the disk of the sun it’s called a transit. Mercury’s path across the solar disk is seen from the Solar and Heliospheric Observatory (SOHO) on November 8, 2006. Credit: NASA.

Mercury’s 7-degree inclined orbit means it typically glides well above or below the sun’s disk at inferior conjunction. But anywhere from 3 up to 13 years in either November or May the planet passes directly between the Earth and sun at inferior conjunction and we witness a transit. This last happened for U.S. observers on Nov. 8, 2006; the next transit occurs exactly two years from today on May 9, 2016. That event will be widely visible across the Americas, Western Europe and Africa. After having so much fun watching the June 2012 transit of Venus I can’t wait.

January 30, 2014December 23, 2015 by Bob King

A Secret Solar Eclipse from Outer Space

The sun seen in six different colors of wavelengths of light as the moon passed across from the perspective of NASA's Solar Dynamics Observatory this morning between about 7:30 and 10 a.m. CST. Credit: NASA

Call it the eclipse nobody saw. NASA’s Solar Dynamics Observatory (SDO) got its own private solar eclipse showing from its geosynchronous orbital perch today. Twice a year during new phase, the moon glides in front of the sun from the observatory’s perspective. Although we can’t be there in person to see it, the remote view isn’t too shabby. The events are called lunar transits rather than eclipses since they’re seen from outer space. Transits typically last about a half hour, but at 2.5 hours, today’s was one of the longest ever recorded. The next one occurs on July 26, 2014.

Today’s lunar transit of the sun followed by a strong solar flare

When an eclipse ends, the fun is usually over, but not this time. Just as the moon slid off the sun’s fiery disk, a strong M6.6 solar flare exploded from within a new, very active sunspot group rounding the eastern limb and blasted a CME (coronal mass ejection) into space. What a show!

Approximate view of the moon transiting the sun from SDO's viewpoint. Credit: NASA — Approximate view of the moon transiting the sun from SDO’s viewpoint. To make sure SDO didn’t run down its batteries when the sun was blocked, mission control juiced them up beforehand. Credit: NASA

SDO circles Earth in a geosynchronous orbit about 22,000 miles high and photographs the sun continuously day and night from a vantage point high above Mexico and the Pacific Ocean. About 1.5 terabytes of solar data or the equivalent of half a million songs from iTunes are downloaded to antennas in White Sands, New Mexico every day.

For comparison, the space station, which orbits much closer to Earth, would make a poor solar observatory, since Earth blocks the sun for half of every 90 minute orbit.

When you look at the still pictures and video, notice how distinct the edge of the moon appears. With virtually no atmosphere, the moon takes a “sharp” bite out of the sun.

SDO orbits about 22,000 miles above Earth, tracing out a figure-8 (called an analemma) above the Pacific and Mexico every 24 hours. Credit: NASA Read more: http://www.universetoday.com/#ixzz2ruidvZJ5 — SDO orbits about 22,000 miles above Earth, tracing out a figure-8 (called an analemma) above the Pacific and Mexico every 24 hours. Credit: NASA
Read more: http://www.universetoday.com/#ixzz2ruidvZJ5

SDO amazes with its spectacular pictures of the sun taken in 10 different wavelengths of light every 10 seconds; additional instruments study vibrations on the sun’s surface, magnetic fields and how much UV radiation the sun pours into space.

Compared to all the hard science, the twice a year transits are a sweet side benefit much like the cherries topping a sundae.

You can make your own movie of today’s partial eclipse by visiting the SDO website and following these easy steps:

* Click on the Data tab and select AIA/HMI Browse Data
* Click on the Enter Start Date window, select a start date and time and click Done
* Click on Enter End Date and click Done
* Under Telescopes, pick the color (wavelength) sun you want
* Select View in the display box
* Click Submit at the bottom and watch a video of your selected pictures

February 3, 2013December 23, 2015 by Jason Major

We Are Made of Stardust

This brief quote by the late Carl Sagan is wonderfully illustrated in the beautiful and poignant short film “Stardust,” directed by Mischa Rozema of Amsterdam-based media company PostPanic. Using actual images from space exploration as well as CGI modeling, Stardust reminds us that everything we and the world around us are made of was created inside stars… and that, one day, our home star will once again free all that “stuff” back out into the Universe.

The film was made in memory of talented Dutch designer Arjan Groot, who died of cancer in July 2011 at the age of 39.

“I wanted to show the universe as a beautiful but also destructive place. It’s somewhere we all have to find our place within. As a director, making Stardust was a very personal experience but it’s not intended to be a personal film and I would want people to attach their own meanings to the film so that they can also find comfort based on their own histories and lives.”
– Mischa Rozema, director

A truly stunning tribute.

See more about this on PostPanic’s Vimeo page. (Credits after the jump.)

Credits:
A PostPanic Production
Written & directed by Mischa Rozema
Produced by Jules Tervoort
VFX Supervisor: Ivor Goldberg
Associate VFX Supervisor: Chris Staves
Senior digital artists: Matthijs Joor, Jeroen Aerts
Digital artists: Marti Pujol, Silke Finger, Mariusz Kolodziejczak, Dieuwer Feldbrugge, Cara To, Jurriën Boogert
Camera & edit: Mischa Rozema
Production: Ania Markham, Annejes van Liempd
Audio by Pivot Audio , Guy Amitai
Featuring “Helio” by Ruben Samama
Copyright 2013 Post Panic BV, All rights reserved

In the grand scheme of the universe, nothing is ever wasted and it finds comfort in us all essentially being Stardust ourselves. Voyager represents the memories of our loved ones and lives that will never disappear.

May 31, 2012April 26, 2016 by Ray Sanders

Help Astronomers Collect Venus Transit Data!

In the Rapa Nui language, Hetu'u means stars. Image Credit: David Rodriguez (Universidad de Chile).

[/caption]During June 5th/6th 2012, Venus will be transiting the Sun, where it will make a rare appearance as a small dot moving across the face of the Sun. Astronomers around the world are planning observations, and one team is traveling to Easter Island in an attempt to reproduce the measurements first made/proposed by Edmund Halley in the late 1600’s, getting precise data of first contact between Venus and the Sun. They are working with students from around the world and are looking for help to connect with more students to participate in the event.

The team is asking for assistance from astronomy clubs and organizations, especially those who work with school children. Since the team will be observing on Easter Island, their view of the transit will be limited (it begins two hours before sunset). Since the team will only be measuring the time of ingress and not egress, the team is reaching out to additional observers to help collect data. So far, the team has colleagues in Hawaii, New York, Australia, Iran, and Holland who will be assisting with their efforts.

Keep reading to learn how your club (or school group) can help collect transit data!

Dr. Jacqueline Faherty states, “As part of the celebration, we are networking multiple school groups around the world that are also viewing the transit so we can make a measurement of the distance to the Sun, combining timing measurements of first and last contact from various points on the Earth.” Faherty also adds, “This is not about making an accurate measurement but rather an attempt to inspire young students, our next generation of scientists, when they see that astronomical phenomena (while rare) can be used to make real and extremely useful measurements while at the same time connecting a network of students from different countries, cultures, political histories, etc.”

To participate you only need do the following:

At the time of the transit have a calibrated clock (GPS clock preferred but not necessary)

From your location we need the time of ingress or egress interior (exterior as well if you can do it). This is the time that Venus has passed into the interior of the Sun. See this webpage for an estimated time of when you can expect the events to occur for your location: http://transitofvenus.nl/wp/where-when/local-transit-times/

As a secondary measurement of the transit we are also going to try to match images taken of the transit from different positions on Earth. If you will be photographing the event please try to capture an image exactly (or close to exactly) on the 10’s of each hour. We will coordinate the rest.

Be sure to take a photograph of you and your students watching/measuring/enjoying the transit

Email Dr. Faherty ([email protected]) saying that you are interested in participating in our group so we can add you to our global network and map: http://www.das.uchile.cl/~drodrigu/easter/transit.html

Once again the team is especially interested in school groups that will be viewing the transit. The team hopes to inspire the next generation of scientists, by demonstrating how astronomical phenomenon can be used for scientific purposes. The team will feature photos from participating groups and the results of their measurements in a blog series hosted by the American Museum of Natural History.

For more information on the team, visit their website at: http://www.das.uchile.cl/~drodrigu/easter/index_en.html

If you’d like to see the math behind the measurements, visit David Rodriguez’s blog: http://strakul.blogspot.com/2012/05/measuring-distance-to-sun-with-transit.html

Visibility information for the transit of Venus can be found at: http://eclipse.gsfc.nasa.gov/OH/transit12.html.

Source: Dr. Catherine Kaleida, Dr. Jacqueline Faherty, and the 2012 Transit of Venus Easter Island Public Outreach Team

May 24, 2012December 23, 2015 by Jason Major

ESA: Unveiling Venus

The featureless face of Venus, as seen by MESSENGER (NASA/Gordan Ugarkovic)

[/caption]

With Venus about to get its day in the Sun — very much literally — the European Space Agency has assembled an excellent video about our planetary neighbor.

Watch the video below:

Once thought to be similar to Earth, possibly even having liquid water and plant life on its surface, Venus has since been discovered to be anything but hospitable to life. Beneath its cream-colored clouds lies a hellish hothouse of searing temperatures and crushing pressure, making attempts at exploration difficult at best. But ESA’s Venus Express, currently in orbit around the planet, has helped scientists learn more about Venus than ever before, opening our eyes to what really lies beneath — and within — its opaque atmosphere.

Venus is still a planet shrouded in mystery (and sulfuric acid clouds!) but we are gradually pulling away the veil.

Video: ESA

September 15, 2010December 24, 2015 by Fraser Cain

Transit

[/caption]

Although the word “transit” can have many meanings, here on Universe Today, we’re talking about astronomical transits. This is where one object in space moves directly in front of another, partly obscuring it from view.

The most famous example of an astronomical transit is a solar eclipse. From our vantage point on Earth, the Moon appears to pass directly in front of the Sun, obscuring it, and darkening the sky. When seen from space, the Moon casts a shadow on the surface of the Earth; only people within that shadowed area actually see the transit.

In order to have a transit, you need to have a closer object, a more distant object, and then an observer. When all three objects are lined up in a straight line, you’ll get a transit. There can be transits of Mercury and Venus across the surface of the Sun, or a transit of Earth across the Sun, seen from Jupiter. We can also see the transit of moons across the surface of their planets. Jupiter often has moons transiting in front of it.

Astronomers use the transit technique to discover extrasolar planets orbiting other stars. When a planet passes in front of a star, it dims the light from the star slightly. And then the star brightens again as the planet moves away. By carefully measuring the brightness of the star, astronomers are able to detect if they have planets orbiting them.

Transits are also helpful for studying the atmospheres of objects in the Solar System. Astronomers discovered that Pluto has a tenuous atmosphere by studying how it dimmed the light from a more distant star. As Pluto began transiting in front of the star, its atmosphere partly obscured the star, changing the amount of light observed. Astronomers were then able to work out the chemicals in Pluto’s atmosphere.

The next transit of Mercury will occur in 2016, and the next transit of Venus is scheduled to occur in 2012.

We have written many articles about astronomical transit for Universe Today. Here’s an article about the transit of Mercury, and here’s an article about the transit of Venus.

If you’d like more info about Astronomical Transit, check out NASA Homepage, and here’s a link to NASA’s Solar System Simulator.

We’ve also recorded related episodes of Astronomy Cast about the Eclipse. Listen here, Episode 160: Eclipses.

Source: Wikipedia