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hst news, Hubble Space Telecope, transit of venus

Sic Venus Transit Solis

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Hubble Spacium Telescopium Vigilabo

There’s this event coming on June 5/6 called the “Transit of Venus” and as I read about it, the Latin translation of it jumped into my head. My mind’s funny like that. Sic Transit Gloria Venus and all that.

So, what’s it all mean? The Transit of Venus is when the planet Venus will move in its orbit between us and the Sun in a sort of mini-eclipse.  It happens very rarely. In fact, after this one, there won’t be another transit of Venus as seen from Earth until the year 2117.

This mottled landscape showing the impact crater Tycho is among the most violent-looking places on our Moon. reveals lunar features as small as roughly 560 feet (170 meters) across. The large "bulls-eye" near the top of the picture is the impact crater, caused by an asteroid strike about 100 million years ago. The bright trails radiating from the crater were formed by material ejected from the impact area during the asteroid collision. Tycho is about 50 miles (80 kilometers) wide and is circled by a rim of material rising almost 3 miles (5 kilometers) above the crater floor. The image measures 430 miles (700 kilometers) across, which is slightly larger than New Mexico.The image was taken in preparation to observe the transit of Venus across the Sun's face on June 5-6. Courtesy NASA/ESA/STScI

As you can imagine, such an event presents some cool scientific opportunities.  One of them will be for the Hubble Space Telescope, believe it or not.  Hubble, as you may know, can’t look directly at the Sun, and it has a heck of a time looking at Venus simply due to logistics, as well as brightness. It can look at the Moon, and for this reason, astronomers have come up with an ingenious method to ‘watch’ the Transit of Venus by using the Moon as a sort of “mirror”.  They tested it, coming up with the image below.  This type of observational technique isn’t new. It’s very similar to one being used to sample the atmospheres of the giant planets as they pass in front of stars as seen from our point of view on Earth.

For the Venus observations, since astronomers already know the chemical makeup of its atmosphere, they’re going to test this technique on a planet they “know” to see if it can be used on the atmospheres of distant planets around other stars. If it works the way they think it will, then it could help them tease out the very faint fingerprints of the atmosphere of an Earth-like planet, even one that might be habitable for life.

During the transit, Hubble will snap images and perform spectroscopy, dividing the sunlight into its constituent colors, which could yield information about the makeup of Venus’s atmosphere. Hubble’s main instruments will get a workout in this test.  The telescope’s Advanced Camera for Surveys, Wide Field Camera 3, and the Space Telescope Imaging Spectrograph will concentrate their attention on wavelengths of light ranging from infrared to ultraviolet.  The whole operation will take seven hours starting before the transit begins and lasting until well after it ends. Because the astronomers only have one shot at observing the transit, they had planned a practice run to see if their idea would work, which included the test observations of the Moon that resulted in the image above.

This is one of those experiments that’s so elegant and cool because it demonstrates the many-faceted ways that astronomers can study objects. You don’t always have to look directly at something; sometimes indirect observations  get you to the same place. And, that’s glorious!

If you want to do a little transit-viewing yourself, visit the Transit of Venus page for details on safe viewing (because the Sun’s involved, you really have to be careful… and NEVER look directly at the Sun. With that caveat, I recommend you check it out. This is the last time this century sky watchers can view Venus passing in front of the Sun and it’s just one of those cool things you can brag about at the next family picnic or company party.

 

astronomy, astronomy research, hst news, Hubble Space Telecope, hubble space telescope

How Time Flies

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Hubble Space Telescope’s 22nd Anniversary and Me

This past week marked the 22nd anniversary of the launch of the Hubble Space Telescope.  It really is hard to believe all that time has passed, but the solid record of science achievements from this famous orbiting telescope is proof that even if you start out with a problematic telescope, you can still do good science. Of course, making Hubble DO that good science took squads of astronauts, ground-based technicians and scientists years of problem-solving to do.  But, they did it.

I was not quite in graduate school when Hubble went up on April 24, 1990. I’d been part of a science team at the University of Colorado for just over a year and a half, led by Dr. John C. Brandt, who was (at that time, among his many responsibilities) the co-Principal Investigator for the Goddard High-Resolution Spectrograph instrument onboard HST.  I was working on a project analyzing Comet Halley images; specifically, I was doing astrometry on images of the comet’s tail so that we could analyze how the tail was being affected by the solar wind as the comet rounded the Sun during its last close approach in 1985 and 1986.

Not long after launch, Jack came back from Goddard Space Flight Center and warned us that there could be some problems with the telescope.  I think that only a few people knew how bad the problems were, mostly because they were still analyzing the images and calibrating the telescope. But, in June 1990, the full news broke and people were devastated by the idea that HST was flawed. I know we at the university were.

But, even as early as August of that year, we were seeing images that didn’t look awful, and I knew from talking with Jack that there was good science to be had — even if it took a bit longer to analyze the images. Our instrument, however, was pretty badly affected, as was the Faint Object Spectrograph.  I started to make notes about the problems with the telescope, and paying attention to the images it was producing. I think I had some idea that I’d write a book about the project someday and I knew it would be good practice to keep notes from the early days. In the meantime, I plugged away on the Comet Halley project, which eventually got published in 1992 as the International Halley Watch Atlas of Large-Scale Phenomena (Brandt, Niedner, and Rahe, with mucho work done by me in a small-credit role).

This Hubble image of the Egg Nebula shows one of the best views to date of this brief but dramatic phase in a star’s life. This is the site of a star in its death throes. At the center of this image, and hidden in a thick cloud of dust, is the nebula’s central star. While we can’t see the star directly, four searchlight beams of light coming from it shine out through the nebula. It is thought that ring-shaped holes in the thick cocoon of dust, carved by jets coming from the star, let the beams of light emerge through the otherwise opaque cloud. The precise mechanism by which stellar jets produce these holes is not known for certain, but one possible explanation is that a binary star system, rather than a single star, exists at the center of the nebula. The onion-like layered structure of the more diffuse cloud surrounding the central cocoon is caused by periodic bursts of material being ejected from the dying star. The bursts typically occur every few hundred years.Courtesy NASA/STScI.

Well, after that one thing led to another—I studied MORE comets as part of the Ulysses Comet Watch, and  I entered graduate school and joined Jack’s GHRS team (albeit as a very junior member).  The science flowing from HST was getting better and better, and the first servicing mission proved that the telescope could be brought “up to spec”.  So, I decided to shop around the book idea, and took Jack on as a co-author.  After a false start or two, we ended up signing a contract with Cambridge University Press, and in 1995, we published Hubble Vision, which was updated a few years later. I also did a planetarium show by the same name, which has been a mainstay of my company’s repertoire ever since (read more about that show here).

I feel like I kind of grew up with Hubble, or maybe we grew up together. I feel privileged to have worked on an instrument team for HST, and to have written about it as extensively has I have.  The telescope has for me–and I hope for all people who follow astronomy exploration–expanded the horizons of cosmic understanding. And that’s a great tribute to its 22 years (and counting) legacy!

If you haven’t taken time to browse the images at Hubblesite.org, take some time to do so. The very act of exploring those pages is a voyage of exploration of the universe.

Check it out!