Celestial hemisphere:  Northern  ·  Constellation: Cygnus (Cyg)  ·  Contains:  Crescent Nebula  ·  LBN 203  ·  NGC 6888  ·  Sh2-105
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RC Collimation Crescent nebula First Light, Tom's Pics
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RC Collimation Crescent nebula First Light

Getting plate-solving status, please wait...
RC Collimation Crescent nebula First Light, Tom's Pics
Powered byPixInsight

RC Collimation Crescent nebula First Light

Equipment

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Description

I've been struggling to get my 14" GSO RC perfectly collimated now for almost 16 months!  This image was made after my second collimation attempt with the Hotech Advanced CT Laser collimator.   Collimating this scope has been like quitting smoking, I have tried everything and I know own every collimation tool made.  I've spent almost as much on tools  as the scope cost that I have been trying to make work!  A wise man told me to dump this scope as mechanically it is a POS, optically it is great, but mechanically it is very hard to tune.  He was right, it is exactly that. Even carefully tightening or loosening up the adjustment screws throws it out of collimation.  For as precise as the collimation needs to be on an RC, the adjustments on this scope are way too crude/coarse.  I have also taken in every YouTube video made on collimating RC's and although they helped get me to where I am now, the Hotech Advanced CT Laser Collimator is what allowed me to get this dialed in.  I had what I thought was decent collimation last winter but it wasn't as good as now and got worse in spring and summer.  Redoing the collimation is likely going to be a seasonal activity, and I plan to mount the Hotech in the roof of my backyard observatory so that I can easily align to it and collimate this scope.  This initial collimation using the Hotech was done on my coffee table inside my house with the collimator on a tripod 51" away.  I have pics on my website, jropics.com.  I ended up needing to remove the secondary mirror to start so that I could collimate the focuser.  I did this semi-reluctantly but at the splines so that I would not touch the distance adjustment screw on the secondary as that also is very sensitive and has to a specific distance.  

This image is 177 x 2 minute OSC subs taken across multiple nights during the first 2 weeks in November 2021.  All of the subs used had an ECC less than .6 and in general, my ECC numbers are now really good.  I can still see room for improvement, but this last collimation got me to the point where most of the image has decent stars and I don't have to do generous crops to get rid of the distracting oval stars.  

Time will tell how productive I can make this scope. 

For those of you that want to jump into this super cool looking Carbon Fiber Truss scope with its modest price, beware. If I was going to get a higher focal length scope similar to this again, I would get something else, maybe a CDK.

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RC Collimation Crescent nebula First Light, Tom's Pics

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