Sky and Telescope
$65.00 plus either $15.00 or $30.00 depending on chosen holographic
or 2 inch
quality laser collimator.
We were given a Meade DS-2114ATS "Short-tube" reflector for Christmas. This is Mead's DST (department store telescope) which is assembled in Mexico with parts made in Taiwan. It has problems, especially with collimation.
Not the least of these is that the scope uses a focal extender lens that fits into the bottom end of the focuser tube to give a nominal focal length of 1000mm in a tube only 16" long. That also means that the secondary is a bit oversized.
The Helix collimator revealed that this focal extender was causing serious vignetting due to improper alignment of the secondary along the primary axis. This could not have been detected, much less fixed, using a Cheshire tube or a single dot laser.
The excellent holographic pattern of the Helix collimator made it possible to eliminate the vignetting entirely, simply by moving the secondary along the primary axis until the entire pattern was visible and perfectly round on the wall.
The rest of the collimation process (centering the laser dot in the primary donut and centering the secondary holder shadow in the pattern on the wall) seemed almost too easy by comparison. When I star collimated... it was PERFECT!
The bottom line is that I could not be more pleased with the collimator! It is extremely well made, perfectly aligned and flawless in operation. It fits quite snuggly in the cheap focuser on my scope, minimizing the error due to wobbling. I don't have much experience, but I surmise that this scope presents as difficult a collimation problem as one could find, and I doubt that I could ever get it this close with any other tool.
By the way, I bought this collimator on Ebay, but Tim Hagan at Helix cared enough about his product to send me a manual and give me valuable advice about solving my scope problem. That's going the extra mile and then some.
Submitted by Roger Boltz - USA