Hotech Advanced CT Laser Collimator

I had been eying these collimators since before they were actually released. They are pretty pricey, though. Luckily I found a used one at a good price.

Here is a review by Uncle Rod, who does a very nice astronomy blog.

My first problem was that the Celestrons don't have bolts around the primary mirror  90 degrees apart. I took the telescope apart and used a rib at the top, a bolt at the bottom and pods on either side to apply White Out for indexing marks. I have had the telescope apart before, when I installed some fans, so it was no problem at all. It took me about an hour to do it. The collimators com with external tabs that can be easily attached to the scope with a velcro strap, but I wanted a permanent solution.

The collimator and telescope need  to be set up on a REALLY solid floor, and having the telescope on a tripod in Alt/Az mode also helps a lot, too. I am too lazy to remove my scope from it's pier every time I want to collimate it, so I improvised.

I made brackets from aluminum flat stock and bolted them to the bottom of my Celestron CPC1100. I attached a 2 x 4 to that and used that to precisely align the collimator in front of my telescope. An added advantage is that I can point the telescope up at about an angle for collimation. My telescope (like most SCTs) suffer from mirror flop.

It is held in place with two wing nuts.

The odd white thing on my finder scope is a piece of PVC pipe that protects the web cam on that finder scope.

When I remove it, I install my counterweights with two wing nuts. The T fitting has been reamed out so that it slides along the long rail.

Front bracket

I drilled two 1/4" holes for the 1/4" x 20 bolts. The bracket is 2" tall. The angle of the camera makes it look like less. I centered the collimator's center with the secondary's center and measured down from the bottom of the tube to the bottom of the collimator's base.

Rear bracket

I didn't measure right - one side was taller than the other, so I bent it to make it level. I spun the telescope upside down, leveled the forks, leveled the tube, then leveled the brackets to match.

This bracket was harder because the tube tapers at the rear. Even though the bracket is 2" tall, I needed to add two nuts to allow vertical adjustment. The bottom one secures the bolt in the board, the top one allows adjustment. I also had to bend the "feet" of the tabs to match the taper of the tube. I used the holes the handle used - my particular scope took M5 - .08 X 10 screws. Some Celestrons may use other size screws.

Overview from the front

I measured forward 20.5" from the front of the tube and drilled a series of 1/4" holes. I turned these into a slot across the board. I use a folded index card to tilt the collimator slightly to make it square with the tube index marks in the tube. I found that I need to move the collimator left or right and raise or lower it to get things lined up right.

To take it on or off, I point the scope to the south. I raise the front of the tube up enough to allow the board to go underneath, line up the bolts with the holes, lower the front of the tube and lock the clutch. The weight of the board holds it in place while I install the wing nuts.