Proposing to use Hubble

Today, optical and ultraviolet astronomers around the world are scrambling to finish proposals for the Hubble Space Telescope. Tonight, at 8pm Eastern Time, proposals are due for the Hubble's 17th Cycle (each cycle is roughly a year) of operation.

This time around, there are two new instruments that astronomers hope to use, if the Space Shuttle's servicing mission works as planned. One is a spectrograph for analyzing ultraviolet light, that high-energy light that can be harmful to humans, but which contains a wealth of information about stars and distant galaxies. This spectrograph is called the "Cosmic Origins Spectrograph," because it will be useful for interpreting light from the earliest galaxies. More to the point, the light that we detect on Earth from the earliest galaxies is ultraviolet light that the expansion of the Universe has stretched into visible and optical light. So the Hubble's spectrograph will be used to explore more nearby galaxies (where we think we understand what is going on), and that information used to interpret the light from more distant galaxies.

Another new instrument will be a new imaging camera, more sensitive than the current one on Hubble. Like other cameras, this one will be able to take pictures in ultraviolet and visible light for studies of just about anything.

So, although these cameras are still on Earth, waiting to be launched by the space shuttle, we are starting preparations to use the cameras. It takes months for people to sort through the hundreds of proposed projects, select the very best ones (and some back-up plans in case one of the instruments fails or repairs don't work), and plan out an observing schedule. By the time that is done, we hope that the space shuttle will have safely traveled to Hubble and gotten back in tip-top shape.

Still, it is a little nerve-wracking to write proposals for broken cameras that we hope to fix, but may not get fixed, or for cameras that are not yet there and may not function exactly as advertised. And, since each proposal takes a lot of time if you want to do it properly, we hope that we are not wasting that time.

Looking through Hubble

Friday was a day that many observational astronomers dread. It was the day that the time allocations on the Hubble Space Telescope were announced. Some of you may remember my writing about this proposal back in January. I submitted a proposal, and 12 hours later, Hubble's camera that I had asked to use quit working. Because so much of the time astronomers asked for used this camera, and because the deadline had just passed, NASA extended the deadline for a couple of weeks.

Two weeks ago, while I was learning about exploding white dwarfs, dozens of astronomers met in Washington, DC to choose which of the proposals would get time on the Hubble telescope. It was a tough job, as astronomers asked for over five times more time than was available. And this was after some large programs were knocked out because they required the now-defunct camera!

When so much time is requested, it is inevitable that perfectly good requests are denied. So, I felt absolutely ecstatic when I learned that I was granted Hubble time. For the first time ever. And I was worried that I was asking for a lot of time, which can hurt a proposal.

It may be 15 months before my images are taken, and I have to keep my fingers crossed that nothing else breaks before I get my data. On the good side, at the end of the next 15 months, astronauts should be up fixing the Hubble one last time.

Curses! Foiled again.

If you remember from a the few posts ago, I spent much of the past 2 weeks writing proposals to use the Hubble Space Telescope. So, you can imagine the foul mood I was in yesterday when NASA announced that Hubble's main camera quit working Saturday morning, only 11 hours and 26 minutes after the deadline on proposals. And, of course, this is the camera I was proposing to use in my work.

The camera is almost fully dead due to problems with the electronics. It may (or may not) be possible to fix it when astronauts come to repair the Hubble in about 18 months, but they have a long list of things to do already, and the astronauts will be installing a camera that is almost as good as the dead camera in some respects, and better than the dead camera in other respects.

The camera that died, the Advanced Camera for Surveys (ACS), was truly the workhorse instrument of Hubble. At the end of the day on Friday, there were 747 proposals to use the Hubble over the next year; 498 of those were to use ACS.

NASA has decided to re-open the system to proposals in order to try and fill the gap left by the loss of ACS. I might be able to change my proposal to use another, older camera that isn't as powerful as ACS. It has a smaller field of view, and is much less efficient at detecting light. But, given the choice between that and none, I'll take the older camera.

Proposing to use telescopes

Whew! I have worked harder this week than for a long time, all trying to get some different proposals to use the Hubble Space Telescope done. I sent one in a few minutes ago, and other collaborators at other institutions are putting finishing touches on others, so I can finally relax.

Many of you probably are wondering, "What the heck is this proposal he's talking about, anyway?" So let me explain.

The vast majority of professional astronomers do not work in front of a telescope. We spend most of our time in an office in front of a computer to do our work. Professional astronomers share all of our large telescopes with other astronomers at our institutions, at other schools, and around the world. So if I learn of a neat object I want to study, I can't just jump in my car, drive to the mountain top, open up the dome and start looking. Somebody else is probably already using the telescope, and they won't be too happy if I force my way in to the dome and try to take over for the night.

In order to get the telescope, I must start by writing a proposal. A proposal has two jobs. First, I have to show that the science I want to do is interesting. If I say I want to see what phase the moon is, people will say that is boring and stupid, and they won't waste time on my project. But if I say I want to look for new moons around Pluto because any such moons would help to tell us how Pluto formed, then people might start to think it was interesting.

Second, I have to prove that my project is suited to the telescope I am asking to use. If I try to take a picture of Venus with the Keck 10-meter-wide telescope in Hawaii, there will be so much light I will hurt the cameras, which will make a lot of people mad. Likewise, if I say I want to take a detailed look at super faint galaxies with a tiny telescope, I won't get anything useful, because small telescopes can't see really faint things.

So, observatories ask for proposals to use their telescopes one to four times a year. A group will then get together to evaluate the proposals. Is the science worthwhile? Is the telescope the right one for the job? If so, they'll put me in a schedule to use the telescope. If not, then they'll say "sorry, better luck next time," and I won't get to use the telescope.

As you can guess, being able to write a good proposal is an important skill for astronomers. I've spent several days (most of the last week and many partial days over the past month) working on my proposals to use the Hubble Space Telescope. But my proposal only has about 5 pages of text, plus a couple of graphs. They won't take anything longer, or else the committee that assigns time will have to sift through tens of thousands of pages, as there are often more than 1000 proposals to use the Hubble! That's a lot of reading.

For fun, I'm putting a PDF version an old proposal from 2004. The project got time on the Keck Telescope that fall. You can try and read it if you want, though I will warn you it is technical and quite boring. And you will find a few grammatical mistakes, typos, and stylistic problems. It's amazing how much of that can sneak through even though you've been staring at the same 5 pages for days.

And to those who have sent me emails in the last month, I will get around to answering them now that I am both home and finished with deadlines. I'm sorry it is taking so long.