by Archer Sully
Viewing conditions at this years Weekend Under The Stars were generally so poor that in other circumstances I would have left early. High haze from the many fires in the west left the limiting magnitude at ~5 at a site that regularly hits 7+. However, one thing kept me there, the prospect of viewing through the 2.3 meter, f/27 classical Cassegrain at the Wyoming Infrared Observatory (WIRO) high atop Jelm Mountain (9656'). It isn't every day that someone puts a focuser and eyepiece in a telescope that made it into S&T as one of the largest of its kind!
The road up Jelm Mountain is about 6 miles long, and very steep. I did see someone bring a fairly normal looking sedan up to the top, but I suspect that it was a rental. High ground clearance is desired on this road http://home.att.net/~rldp/9911rmm1.htm.
Ray Martin of the University of Wyoming is the official caretaker of WIRO, although in reality we all knew that Mew Bootis (Boots), the observatory cat was really calling the shots. WIRO is a fairly small facility, just the one scope with an attached control room and dormitory for the staff. The living room is equipped with a TV, VCR and a complete collection of Star Trek for those nights when the staff get trapped by 100+mph winds. When the wind isn't blowing, 1/2 arcsecond seeing is said to be common. And to think, at one point the UofWy was thinking about scrapping this observatory because the road costs too much to maintain. Fortunately, Ray made them see the error of their ways, and with a new 10.5Mbps microwave link, WIRO can now be controlled from anywhere in the world through the magic of X11, and is getting NASA funding to help keep the facility running.
Fortunately, it is not completely operational as a remote observatory yet, and the brief window allowed Ray, an avid amateur as well as professional astronomer, to have a focuser made to bolt onto the Cassegrain focus of this world class research telescope.
A further word about the scope is in order. Many IR telescopes aren't designed to work in visual wavelengths, however WIRO was figured to work from the visible down to 20 microns or so. This evening the scope was set up for optical, so the secondary and core baffles were in place. The scope itself sits on an offset Engligh yoke mount, similar to the Hooker, but with the declination bearings mounted on top of the yoke to permit viewing in the polar regions. The moving weight of the scope is about 60,000lbs. The 2.3 meter primary has a f/ratio of about 2.1. The secondary magnification is almost 13x, the diameter is 8". Lets see a Newtonian with a central obstruction of less than 9% by diameter! A 50mm eyepiece was used, giving a magnification of 1242! More info on WIRO can be found at http://physics.uwyo.edu/observatories/wiro/.
The evening wasn't the best. Winds were moderate, but the high haze was hurting transparency. And because this event was organized along with a large regional star party, there were about 30 people waiting in line to look through the eyepiece. Oh well, sacrifices must sometimes be made.
The group that I was in (thanks for driving, Ray W.!) arrived at about 10:00. The first group of visitors was supposed to be finishing up, but for some reason they were slow to leave ;-). M57 was in the eyepiece, and quite a sight it was. The central star was held in direct vision with no effort whatsoever, and as much structure as is visible in a good amateur photograph was clearly visible.
Next up was NGC6543, the Cat's Eye. This object was further above the horizon than M57, and it showed. Amazing loops and tendrils of gas were visible, along with a central star that burned brightly in the center of the field. This view was astounding, and made all of the waiting and driving more than worthwhile.
NGC5866, aka M102 was up next. In the 92", only part of it was visible, but it ended up looking more like 4565 than anything else. Less detail was visible than in 6543, althoug it was still an impressive view.
I mentioned waiting. We had to do a lot of it, because while WIRO is computer controlled (and quite well, I might add), the UI leaves something to be desired. A series of command line controls are entered into a Wyse50 terminal, and the organization is by observing lists for the various users of the telescope. So if you want to find M57, you first have to find a list that has M57 in it, tell the software to use that list, and then tell the scope to follow the item in that list. Since most IR astronomers aren't interested in the same things that we are, it was tricky to find some of these objects. I offered to write some new software for it, but Ray said that they had tried that, and the head of the department had thrown a fit ;-(.
Last target for the evening was Uranus, and it was a chore. The volunteer operator for the evening wasn't able to figure out what the software wanted, and since I was standing right there I allowed myself to be coerced into driving the scope ;-). In the course of slewing, however, the scope bumped against the observing platform, and it took a while to get it straightened out. Finally, Uranus was located. While the detail wasn't great (we were looking close to the horizon through a 92" column of air!) we did manage to spot at least 3, possibly 4 Uranian moons. A look at the Astronomical Almanac didn't really help that much, but we took credit anyway. The planet itself looked more like Jupiter does in a typical amateur scope in terms of size and brightness.
As we were leaving Ray said something about arranging rentals of the facility for $1000 a night. Seems like a bargain to me.
Thanks again to Ray Martin for hosting this wonderful event, as well as finding a cure for aperture fever!