A CATSEYETM
Collimation System review
by Alex Langoussis - 6/1/98
Atlanta Astronomy Club
Atlanta, GA


"Hi All, Those of you at the Star Gaze and/or the ATM meeting about collimation will remember Jim Fly from Huntsville, and his Cat's Eye collimation system. My never(soon?) ending battle to get my 8"F6 1979 Meade Newtonian up to speed gave me the perfect opportunity to try this system out. First, I must say that I love his plastic template for marking the center of the mirror. Much easier than cutting out construction paper, etc., and definitely accurate. Also part of the system is the primary center marker, which is a triangular piece of reflective tape. For me personally, this has several advantages. Most important, it is the first center marker to work with all the various collimation tools I use. Since it is reflective, it works with the AstroSystems laser. (The black square used by Tectron did not work well with the laser.) And, if one wants to use the Tectron Cheshire, it works perfectly with it, too. Before, I used a notebook ring, so that I could use the laser. But using the notebook ring with the Cheshire was difficult. The reflective marker solved the problem, and is usable with all the different collimation methods. The center marker is triangular so that (when properly placed), you know exactly which collimation screw to turn when adjusting the primary. Many of you may remember one of the tricks I showed at the ATM meeting on how to do this. But the triangular marker made this really easy. What a superb idea! The Cat's Eye itself is similar to the Cheshire. It has a reflective ring inside that corresponds nicely to the size of the primary marker. The Cat's Eye differs in how you introduce light into the telescope, so that you can see what you're doing. With the Cat's Eye, you shine a bright light down the telescope tube. With the Cheshire, you shine a light into the side of the Cheshire itself. At this time, I still prefer to have the light right there at the focuser, instead of having to reach around the end of the tube. Using the Cat's Eye, it's just a matter of time before I drop a flashlight down the tube! I must say that I was encouraged that collimation results were identical, in that both the Cheshire and Cat's Eye matched. At the ATM meeting, Jim had mentioned how you can do an extra-fine adjustment with the autocollimator and the Cat's Eye center marker, but for the life of me I can't remember the procedure. Jim, I know you're reading this, so please jump in and explain again! I have not tried the Cat's Eye in the field yet, just in my dining room! But at this point I'd certainly recommend the system. Not sure if Jim includes a sight tube in the package. If not, hopefully it will become part of it, as well as an autocollimator. Combined with a super easy primary marking system, the Cat's Eye is a wonderful aid to getting the most performance from a telescope. I'll let you know later how the stuff works on the observing field, as well has how it performs on the 15-inch F5. Alex" * /\ /\ /\ Alex Langoussis / \ / \ / \ Atlanta * * /----\ / \ / \ * / \/______\/ \ aleko@mindspring.com *