In February, after a lot of coaxing by veteran astronomy friends, I finally gave in and bought a chair for observing. BOY, am I glad I did.
There are many chair designs and implementations, including the favorite "do it yourself" project known as the "Denver observing seat" (see members.tripod.com/denverastro/seat.html), but having inherited none of my father's carpenter skills, I chose to go with a ready-built chair from buyastrostuff.com.
The chair retails for $95 plus shipping. This chair has a very flat profile (4") when folded and weighs 10 pounds. The dual metal arches support more than 300 pounds. (I've seen pictures of a 250+ lb. man sitting on the lap of another 250+ lb. man sitting on the chair. It isn't a pretty sight, but it's an impressive demonstration of the chair's capacity.)
The seat on the chair is adjusted by slightly lifting the seat with one hand, moving up or down to the desired position and sitting down. The grips immediately lock and you can release the seat. It's quite easy to do while you're at the eyepiece and the process becomes second nature surprisingly fast.
Although it's called a "chair", I find myself primarily using the chair as the third leg of a tripod with my legs as the other two....legs(!). The chair provides some support and a lot of balance - something you need while hunched over the eyepiece. It's very much like the experience of sitting/standing with a bar stool or a lab chair with the added convenience of easy adjustment.
The chair adjusts from low to high levels (18" to 32"). Even though the base isn't very wide, I was able to sit in the chair at the highest level with very little wobble and no sense of imbalance. At the lower levels, the chair is quite comfortable for operating a computer at the typical portable table heights. And while waiting for some long exposures, the chair was really comfortable for leaning back and "resting my eyes" for a few minutes.
I've only used the chair on the hard, flat surface of my driveway so far, but according to several other users, it's equally steady on dirt surfaces.
Of course, I knew there were comfortable chairs available for astronomy use, but I never appreciated the level of comfort they provide until I started using my new chair. The stability that a chair offers lets you look at objects comfortably when the viewing angle would require muscular or awkward postures. This can be very important for delicate nebulae or with eyepieces having limited eye relief. If found myself spending much more time with objects than I did prior to owning the chair. And when viewing from my porchlight irradiated driveway, I was able to use my hands to block directly intrusive light without compromising my balance. Finally, the chair just made me more comfortable during viewing by relieving pressure on my back, neck, and leg muscles.
Before I got the chair, I had wondered what all the fuss about chairs. Now I know: It makes observing more fun and less work. I recommend getting or making a chair to anyone who observes a lot. The chair from buyastrostuff.com is a very good choice and I'm glad I made the investment.Published in the April 2004 issue of the NightTimes