Help with collimating a NexStar telescope
Posted 18 January 2013 - 08:26 PM
Posted 19 January 2013 - 05:13 AM
There's much been written on the subject of Schmidt Cassegrain telescope collimation and of tools reported to ease the process: noteably lasers. However, in my opinion, those which are perfectly suitable for Newtonian 'scope collimation are useless for this task while those claimed to be suitable for SCT collimation, are expensive and apparently still unproven, judging by a lack of any vast number of reviews that I've ever seen !
In essence therefore, all that is needed is one's viewing eye, a clear still night sky and an ambient temperature, acclimatised 'scope, (in this case your 8SE).
However, there are one or two "tools" which might be employed on an indirect basis; namely, an artificial star, a simple webcam, linked to a laptop and, to facilitate centralisation of the out of focus star image on the LT screen, an overlaying grid pattern. The replacement of the existing collimation screws by a set of "Bob's Knobs" may also be beneficial to the adjustment process.
Perhaps these links may be of interest to you ?
Hoping this helps, but if you've any further queries, I'm sure we can assist further.
Posted 19 January 2013 - 09:58 AM
What Tel said.
Save your money. The vast majority of collimation devices are not helpful on an SCT. Hotech makes one specifically designed for SCTs, but it is $$$ ! The best SCT collimation device is a high powered eyepiece and a star.
Posted 19 January 2013 - 11:52 AM
I do own an artificial star and I think I replied to a recent thread about them...What is said is althouht I do use the AS to collimate my scopes I do NOT use it on my Scts...
Hoteck makes a $500 laser system for scts that reportedly works well once you set everything up correctly but for $500 bucks it is way too much money
Posted 19 January 2013 - 05:22 PM
Oh, and Art's handy chart (reproduced below)