Russell's Blog

For the last couple of weeks or so, Jupiter has been bright enough to cast a visible shadow on a moonless night. I'd been peering at it through the trees as I walk around town, thinking about buying a telescope. Then news came about the Black Smudge on Jupiter, discovered by amateur astronomer Anthony Wesley -- on a homebrew Newtonian -- and I thought, "That's it. I'm buying a telescope."

The problem is, I've never owned a telescope. When I was a kid, we had an ancient four inch refracting telescope, but it was missing some crucial parts, like the focusing drawtube, parts of the tripod, and one of the cast iron counterweights was broken in half (probably from coming unscrewed and dropping on the pavement). I played with it a lot, but for obvious reasons I never got to actually do any astronomy with it. When I lived in Ohio, I once used the Natural History Museum's incredible 500-mm Dall-Kirkham Cassegrainian to peer at Saturn.

Almost all of my telescope knowledge I owe to my college Optics course and its lab section, and the endless mind-numbing, poorly worded homework problems involving lenses and mirrors and pictures of carrots (I never found out why the objective was always a carrot). I could probably design a simple telescope on paper, but calculating a magnification factor and peering through a scope are very different experiences. I've been rummaging through telescope reviews on the internet for years, wondering how much I would really care about this or that optical aberration, or if I should spend more money to have less of it.

I decided to buy a really inexpensive telescope just to have a point of reference. This is what I've been playing with all weekend :

This is a Celestron FirstScope, purchased from Amazon.com for $43. Stephen R. Waldee wrote a ridiculously detailed review of this little thing.

When I was in eighth grade, everyone had to buy a Texas Instruments TI-82 graphing calculator. At the time, I had a computer (an elderly Macintosh SE loaned by a friend's mother, who had upgraded to a Quadra), but this was back when compilers were comically expensive. I could run programs, but I couldn't write them. The TI-82 wasn't as powerful as the Mac SE, but it did have a very well designed built-in BASIC interpreter and a fantastic library of functions. While my algebra teacher was tediously reviewing the previous day's homework, I tuned out and taught myself programming, Boolean algebra, functional formalism, iterative numerical methods, graphics, animation, and all sorts of other cool and useful things. Those stolen hours in eighth grade led directly to a degree in physics, four years working as a computational physicist, and graduate school in computational biology. The TI-82 was available, and it was extremely well-designed despite its limitations. In fact, I learned as much from what the TI-82 couldn't do as I learned what it could.

That's kind of what I have in mind for the FirstScope.

Anyway, I've been having a grand old time looking at Jupiter and the Galilean moons. Here's (more or less) what I've been seeing :

This is a 1 second exposure using a Takahashi TOA-150 that I rented for a few minutes using Global Rent-a-Scope. This guy beats the stuffing out of my telescope (the Takahashi is a $27,000 instrument!), but I'm really not using it for its intended purpose. What I see with the 4mm eyepiece on my telescope is essentially the same as what you see above.

I checked Stellarium to see which moons are which. From left to right, it's Callisto, Ganymede, Jupiter, Io, Europa, and the star HIP 107302.

Jupiter will occult HIP 107302 later today. This is kind of neat, since HIP 107302 is bright enough to see with the naked eye (at least when Jupiter isn't near it). If you Google for "Jupiter HIP 107302," you'll find that it's the brightest star Jupiter will occult for the next hundred years. Light from HIP 107302 will illuminate Jupiter's atmosphere from behind, and, I presume, yield some interesting data about its structure and composition for people suitably equipped to make such measurements.

Just for fun, and to be fair to the Global Rent-a-Scope people, here's another shot I took around midnight of Andromeda that really shows off the Takahashi's beautiful optics.

This is a 600 second exposure. I could probably do better if I fiddled with the exposure a bit, or did a color series instead of a single exposure, or knew anything about post-processing astrometric photography.

I've looked at M31 with my own little telescope, but all I see is a dot where the central core is. On the other hand, I was using the telescope sitting on the hood of a car in my apartment building parking lot under an obnoxious buzzing outdoor lamp. No night vision whatsoever. My verdict is that I've already gotten $43 worth of astronomy out of the FirstScope, and I haven't even used it under decent viewing conditions.