Hubble saved, again

NASA Administrator Michael Griffin announced today that the Hubble Space Telescope would receive one last shuttle servicing in 2008 to extend it's life another 2 or 3 years. Hubble is currently suffering from some system failures and will not last much longer without some help. Because the shuttle program is also not long for this world, there was considerable debate about the wisdom of "wasting" a shuttle mission on a servicing trip to Hubble. Most of the remaining shuttle missions are needed for the completion of the international space station. However, scientific interests appear to have won out on the Hubble decision. If Hubble is not serviced soon and fails in the next year or two, there will offically be a gap in our optical observations of the universe from Earth orbit because the next generation space telescope does not launch until at least 2011. A Hubble servicing will keep it alive into 2011 until the James Webb Space Telescope is launched. This appears to be the course of action that NASA announced today. So, in May 2008 Shuttle Discovery will pay Hubble a visit, 18 years after the launch of the great observatory.

Your name here

I'm not really sure what I think about this new "send your name into space" movement with the space program, but I think I'm ok with it. Anything that attracts public attention to space missions is a good thing. So, I thought I'd put this out there for anyone who is interested. Dawn is a spacecraft mission to the asteroid belt that launches next summer. It arrives in the asteroid belt in 2011 and will study the two largest asteroids there, Vesta and Ceres. A microchip will be onboard that contains the names of people who submit to this website by November 4. It looks like you can submit as many as you want, and the current tally is about 170,000 names. So, submit yourself, submit your family, submit your cat, it's not every day you get to send your name to an asteroid.

Crescent Moon and Venus

We have all seen the Moon during the day, but not many people know that the planet Venus is also visible during the day. It's generally not visible to the naked eye, but if you know where to look you can easily spot it with binoculars or a small telescope. The image above, taken by Ivan Eder in Budapest, Hungary, shows not only a daytime crescent Moon but a crescent Venus just to the left of the Moon. The image captures an incredible distance range of millions of kilometers and reminds the viewer of the importance of perspective. Venus is much larger than the Moon but because it is so distant it appears almost insignificant in this image. How is it that Venus is visible during the day? Venus is actually one of the brightest objects in our sky. Completely shrouded in cloud cover, it reflects an enormous amount of sunlight into space. Being relatively close to the Earth it becomes a very bright object in our sky, bright enough to overcome a brilliant blue sky.

Mauna Kea

The picture shows the domes of the observatory on the extinct volcano Mauna Kea on the big island of Hawai'i. It was taken from the Kohala Coast on the western shore of Hawai'i at a distance of about 30 miles from the peak. This was the best view we had of the domes all week, the peak was clouded in the rest of the week. The telescopes on Mauna Kea are diverse and international. Over a dozen countries are represented at the observatory with about a dozen different telescopes. The United States, Canada, Britain, Japan, the Netherlands, Taiwan, and France all have a stake in the telescopes on the mountain. Mauna Kea is very well suited for optical astronomy but is extra special because the water vapor content of the atmosphere at 14000 feet elevation is quite low. Low water vapor content is essential for infrared astronomical observations from beneath the Earth's atmosphere. Water vapor in the atmosphere absorbs infrared radiation from space, making earthbound infrared observations very difficult. Furthermore, Mauna Kea is one of the few locations on Earth at 14000 feet where the landscape is amenable to construction. So, low water vapor content and a relatively friendly landscape make Mauna Kea an astronomical gem here on Earth.

Unfortunately, several of the telescopes and their housings were damaged in the large earthquake that struck the Hawaiian islands on October 15. Damage is still being assessed, but initial indications are that at least one dome was pushed off bearings and a few telescopes were knocked out of alignment. Provided lenses and mirrors survived unscathed, the damage is not too bad. Regardless, some of the telescopes will probably be out of commission for months.

back in a (green) flash

Sorry for the delayed return, a week in Hawaii can hamper one's interest in doing much of anything other than sitting on the beach and enjoying frosty drinks. Hawaii itself actually provided a few interesting points of astronomical interest, and I'll get back in the swing of things with those. I saw my first green flash last August on my first trip to Hawaii. There are enormous details involved that I don't entirely understand, but the green flash is basically a refractive phenomenon in which the rising or setting sun shows a brief (1 or 2 seconds at most) flash of green light just before crossing the horizon. The light from the sun is bent through the atmosphere, different wavelengths being bent to different degrees, and for a brief instant green is separated out from the other colors. After seeing this spectacle last summer in Hawaii, I was determined to not only see it again on this trip, but also photograph it. I was successful on both counts. The photo here was taken on our second night on the big island, probably the best sunset of the entire week. It's not perfectly in focus, but the green is definitely there. A third viewing of the green flash followed on our second to last night. Considering that many people never manage to see a green flash, even with years of trying, I consider myself lucky to have now seen three.