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It's an ED80 with the stock focuser. I think there is some astigmatism somewhere as my stars can be a little stretched and so I want to see if I can use a collimating laser to check if the focuser is in straight. (I'm also going to make a determined effort to get the spacing right between the FF//FR and the sensor, but that's another story). I can't see any threads that get into the detail of lining up the focuser with a laser.
If I put the laser in with the target bit facing up, then the red dot that bounces back off of the lens is slightly off centre on the target on the collimator. If I loosen the screws, turn through 90deg, retighten and look again, then the red dot is in a different place and so on all the way through 360 deg. I'm thinking that the red dot should be central (as when collimating a Dob that I used to have). Is that right?
It may be that the laser needs collimating, but I'm not sure how to do that.
Any advice on whether this approach is going to get me anywhere would be appreciated.
I need a a really accurate,easy to use collimating tool. I have a used laser collimator but it does not fit snugly in the focuser so I feel it’s not very accurate. The idea of collimating causes me some anxiety anyway, so accurate and easy is the key! Can any of you offer any suggestions to help me out?
I have encountered a unique problem last night while trying to image using my GSO RC6.
The scope is well collimated using a long Cheshire as well as a Howie Glatter single beam laser for verification. CCD inspector also gives me good results when checking with an artificial star. However, when I check using a collimation cap the innermost shadow looks offcentered as well as when I pointed the scope on a real star yesterday (Alp Libra) as well as Spica, it showed a crescent shaped star. This I found to be really weird. Anyone have any idea whats happening here? I live in Bangalore, India, so there's virtually no cool down time required. The temperature gradient between outside and inside is very little if any.
I recently got myself a GSO 6" f/4 astrograph, but seems like the secondary mirror was quite off. I then tried collimation using Astro Baby's tutorials, and others around the net. I've had a few Nets during the past 20 years, but this one seems to be a bit of a pain to get right. The secondary holder is a bit stiff. Anyone here done any mods for the scope and have reasonably good performance? I'be attached an image with Mire De Collimation circles. Image shows the reflection of primary, followed by the edge of secondary and followed by the grey card placed behind the secondary, which ends with the focuser tube. Any help will be appreciated.
Edit: If I were to move the secondary towards 2'o'clock position, could it solve the problem?
Am very new to this so apologies right from the start. I have recently just bought a skywatcher akyliner dobsonian 200p and i set it up. However the image is very blurry even when i remove all magnification and just look into the primary mirror eveything looks very blurry including the moon or nearby trees etc. I am unsure what the issue could be as i am eager to get started on my stargazing!
Could someone please assist me or at the very least point me in the right direction.