Hi, is anyone using Bresser Messier Exos 2 EQ GoTo mount? I bought this mount and was using 3-star alignment as the alignment process. But post-alignment also, when I navigate to a star, it is in a gross error of 5-10 degrees. Most probably I am doing something wrong. It would be really helpful if someone could share his/her insight on what the issue could be and how I could debug this.
Thanks and Regards,
Arkadeep
Is it polar aligned? Check this link (Easy Polar Alignment for Astrophotography - [Step by Step]). You don’t need a polar scope, you can use any Stargazing app to find the north celestial pole.
Yes. I did a rough polar alignment using “PS Align Pro” app. After that, I had done the fine polar alignment with drift alignment method. Still when I was trying to go to some target in different part of the sky, it was grossly off. I was just wondering whether this is a common issue and whether there is an easy fix for this.
Can you mention what scope you are using?
Hi, sorry for the delayed response. I am using GSO RC 8” scope.
The mount should be able to handle the weight. Have you set the location, date, and time correctly? Have you connected the RA and DEC cables in their right sockets? Do check all connections if they are snugly fit.
Do you have a camera connected to the scope?
Yes. I had put the exact location, date and time. Is there any troubleshooting algorithm for these goto mounts? I mean, I had seen someone (most probably you) had made a DIY goto mount but how did you test its functionality and all? Any step by step guide would be extremely helpful.
I have a bresser messier deep-sky camera attached to the telescope. Its very light (not more than 150 grams I feel) though.
I haven’t used that specific goto so I don’t know. But if the mount isn’t pointing correctly, it’s usually because of incorrect location, time, connection problem, faulty cables etc. It should also be in the “Home” position (scope parallel to the polar scope and pointing to Polaris) before you start doing anything.
Did you check this: https://www.youtube.com/watch?v=Cuh9ZdpPIGU
Can you post some photos?
You could also check with the seller for any pointers, and also to see if the setup is faulty.
@Arka, how do you pick the alignment stars for alignment? It’s recommended to pick stars that are far apart from each other.
While doing the alignment, you will face significant offsets for the first two stars. However, the third star should be more or less in the center of the FOV and you should use this step for fine-tuning. I usually plan my stars such that the first two are far apart(maybe on opposite sides of the sky) and the third is close to the object that I am planning to shoot.
Hi @vijay, I feel the polar alignment is not fully correct for me. Yesterday I hand-calculated HA (LST-RA) and DEC for the chosen target and I could see the mount is moving almost correctly everytime. I feel I am messing something up during the polar alignment. @siva yes, I had chosen three stars uniformly distributed across the celestial meridian. But I am confused what errors these three-star alignments take care of. Does it take care of polar axis misalignment issue also?
Hi @Arka , when you were using an App to align your mount to Polaris, was the scope also pointing to Polaris? Didn’t you use the polar scope?
To roughly GoTo a target, you really don’t have to precisely polar align the scope or perform a 3 star alignment, although these things are important. As long as you roughly align the mount with Polaris with the polar scope (I hope you know how to use it) and do a single star alignment, when you do a GoTo for an object, the mount should move the scope to almost where the target is.
You should then be able to use the finder scope to bring the target to the field of view using the hand controller.