HoTech Laser Collimating

[Jiggy 67]

I have used the HoTech SC Laser Collimator a couple of times now and I thought I had used it successfully. However I was recently browsing FLO and came across the product page for the collimator where I saw a note stating that prior to using the collimator a sight tube should be used to check/align the secondary mirror. I don’t quite understand this as the collimator clearly aligns both mirrors without any need for further equipment. I have done this and it is clearly stated in the HoTech video and the instructions which accompany the collimator. Am I missing something in the collimation process??

[fwm891]

You need to align the focuser with the secondary optic first, then you can align the optics. If the focuser isn't aligned orthogonal to the OA then your plane of focus will never match the plane of the sensor.

[johninderby]

Get yourself a Concentre. They are available in 1.25” and 2” versions and absolutlely nothing else does as good a job of setting up the secondary mirror. Having a properly setup secondary is key to good collimation.

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p5506_TS-Concenter-2--colimation-eyepiece-for-Newtonian-Telescopes.html

A regular Cheshire eyepiece is better than nothing and will help get the secondary close enough to allow using the laser to finish the collimation but if you want the best collimation get the Concentre. It’s one of those tools that once used you won’t go back to a Cheshire.

Edited January 3, 2020 by johninderby