Telrads, Hacksaws, and Thanksgiving Eve at Montebello
By David Kingsley

I went up to Montebello Wed night to enjoy what may have been the last clear skies of the holiday weekend. When I first got out at the gate about 10 pm,the wind hit me hard enough that I thought about turning around without setting up. The forecast looked so lousy for the rest of the weekend, however, and Orion and early winter constellations were already beckoning in the clear sky. I had my TAC permit with me (fine for the regular Wed night Star parties), drove in, and positioned the car to form a windbreak against the gusts from the southwest. My scope for the night was a Starmaster 7 inch Oak Classic Dob that I got in August (one of the last batch Rick Singmaster made). This small portable Dob is used in a sitting position, and the viewing position was low enough that I was able to avoid most of the wind problems by setting up close to the strategically positioned car.

One of my main tasks of the night was to test out a new finder scope. The StarMaster came with a Telrad, (my first experience with this popular unit finder). I have found it frustrating to use as the only finder on the scope, particularly since much of my viewing is done in suburban skies where fainter stars are not visible. I have heard others suggest using a binocular to view through the Telrad to see more stars, but I have found it both tricky and uncomfortable to line this up and still steer the scope. I therefore decided to experiment with a new finder, taking bits and pieces of advice from several sources:

  1. From the October issue of Sky and Telescope: a simple plan for mounting a finder scope made from one half of a pair of binoculars, using a pair of 3 inch PVC rings mounted on wood blocks, and nylon screws to provide 6 fold adjustment for aligning the binocular half.

  2. From Jay Freeman's Advice to Beginners: the recommendation to get a pair of 7x35 Tasco binoculars (model 2001, $29.95 at Sears). These have a nice wide field of view (something like 8.5 degrees) and a bit more magnification and aperture than a 6 x 30 finder. Unfortunately, these binoculars cannot be easily dissambled into two halves. Therefore, I made liberal use of a hacksaw to cut them in half (which seemed particularly fitting given that they had originally been recommended by Jay).

The various hardware parts for mounting the new finder cost about $2 or $3 from Ace Hardware. I built the small wooden platform with legs that fit into the base of the Telrad, letting me swap the two types of finders easily depending on preference. For some simple reticle lines, I made various combinations of lines, rings, and crosshairs in a Mac drawing program, and printed them with a laser printer on overhead transparency sheet. By cutting out 25 mm circles from this sheet and slipping them inside the eyepiece of the binocular, I was able to get some simple orientation lines, and a choice of cross hair thicknesses.

I was completely sold on this new set up by the end of the night. The simple wooden mount gets the finder up high enough from the surface of the telescope tube that it is relatively easy to look through from the same seated position used at the eyepiece. The very wide field of view of the Tasco 7x35s provided great orientation to large regions of sky. Finding things was a snap in an upright, 8 plus degree view, with enough magnification to see not only guide stars, but also to just make out some of the targets I was looking for (Messiers, bright NGCs, and double stars). Being able to put the scope right on a target or target region avoided endless cyles of eyepiece swapping and refocusing that I used to go through with the Telrad. (Point to some region, often largely devoid of stars, look through the scope and try to guess where I really was, starhop through the scope using a low magnification eyepiece, swiveling the atlas for the upside down view, then swap eyepieces and refocus when I finally was on the object).

I'm impressed with all the experienced Telrad users who can use the Telrad as their primary finder. For me, the new binocular setup preserves the upright view of large portions of sky of the Telrad, but greatly increases the number of stars and objects visible, and dramatically cut the time required to find and view objects. As an unexpected benefit, the finder also often suggested many new objects to look at that I might have otherwise missed. There are lots of pretty clusters in the in the Milky Way region that runs through the base of Gemini, above Orion, through Monocerus and between Canis Minor and Canis Major. Many of these were just visible in the new finder on my way to other things on Wed night, and led me to look at some targets I would have definitely overlooked. I had enough fun picking up targets and viewing new objects that I stayed till the clouds came Thanksgiving Eve (about 2:15am). Glad that the wind didn't scare me off at the gate, (and that Thursday was a holiday).