Collimation Connundrums

[astrosathya]

I purchased a standard GSO 6" RC telescope late 2016. As with other RC scopes, I've had my share of problems with the collimation. As many of you know collimation of the RC is a bit of a struggle. After reading much of the material online, it seems that the procedure boils down to multiple iterations with the simple Cheshire and something called as Hall of Mirrors aka multiple reflection effect. Below are the test images from tonight. Reference star is Canopus. All images are inside of focus, unless mentioned. The small rectangle shows the location of the star in the FoV. I also built myself an artificial star from Aluminum foil and LED torch and checked the collimation indoors. The indoor test is quite better as seeing conditions have not affected the judgement. As you may all notice, I've used Mire De Collimation exe file for final checking. I've not used a laser collimator or Howie, just a simple Cheshire and a real star, though I'd love to try again with a Howie Glatter.

[Jkulin]

That look spot on Sathya.

I've had a learning curve with my RC's, but it turned out to be such a simple fix.

I had weird shaped images and couldn't put my finger on it, it then turned out to be the dew heater pumping out too much and distorting the primary, as soon as it was switched off, good stars shapes were back.

I have a Howie Glatter and it is great for getting things nearly there, but a real star test will still improve things, this was a quick and dirty check of the collimation on my 8" RC, however it still needed a tweak when I set it out of focus on Arcturus.

I really don't think there is any better check than on a real star.

Your RC looks really good.

[astrosathya]

15 hours ago, Jkulin said:

That look spot on Sathya.

I've had a learning curve with my RC's, but it turned out to be such a simple fix.

I had weird shaped images and couldn't put my finger on it, it then turned out to be the dew heater pumping out too much and distorting the primary, as soon as it was switched off, good stars shapes were back.

I have a Howie Glatter and it is great for getting things nearly there, but a real star test will still improve things, this was a quick and dirty check of the collimation on my 8" RC, however it still needed a tweak when I set it out of focus on Arcturus.

I really don't think there is any better check than on a real star.

Your RC looks really good.

Thank You very much John.  Regardless of the good collimation, if skies remain to be as bad as they are, all this effort is a waste, though I admit its part of the fun.