Movement (not sure what the correct term is!)

[mbalkham]

Quick question from a newbie, crop below was taken last night. There's obviously some movement (or drift or whatever the correct term is!) on longer exposures (this one was 3mins).  I had assumed it was down to poor tracking (guide scope setup is on order). But then I got thinking is this more likely to be result of something else? I've been limiting my exposures to about 90secs to avoid the problem but that's only a temp fix!

1. A poorly balanced scope?
2. Poor polar alignment
3. Poor tracking?
4. Mount overloaded?
5. Something else?!

Any ideas? Thanks in advance

[Geordie mc]

Looks like a polar alignment issue but getting this precise enough to do 3 minute subs will be tricky. I think you'd need to drift align. Various tutorials for this on the web so try googling it. Sure there are vids in youtube. Hopefully when you're guiding it won't be an issue.

[Scott]

3 mins for a 1000mm scope on an eq5 is a massive amount of time. I was always happy with 90 sec unguided. I'd  stick with that until a guide setup arrives .you will also want perfect balance and pa. windy nights are out as the 200p will act like a sail. Please don't think I'm trying to put you off. I really enjoyed imaging with the same setup andwhen everything comes together its a great feeling . have you concidered a smaller frac (80mmish) for imaging? I know its a money pit but the shorter focal length and weight will suit the eq5 much more 

Most of all, make sure you enjoy it

[Pyrodave]

3 mins for a 1000mm scope on an eq5 is a massive amount of time. I was always happy with 90 sec unguided. I'd  stick with that until a guide setup arrives .you will also want perfect balance and pa. windy nights are out as the 200p will act like a sail. Please don't think I'm trying to put you off. I really enjoyed imaging with the same setup andwhen everything comes together its a great feeling . have you concidered a smaller frac (80mmish) for imaging? I know its a money pit but the shorter focal length and weight will suit the eq5 much more 

Most of all, make sure you enjoy it

I must admit I've never got anything close to 3mins with my eq5 unguided 

just got an adaptor for spc900/finder so if we ever get clear skies i'll be giving guiding a go 

[mbalkham]

Right oh sounds like I'm not doing anything stupid (worth checking cause it's very possible!). 

I have just got Alignmaster to try to improve my PA. Trouble is my garden has an obstructed view of Polaris so I'm always trying to set-up looking through the branches!!  I did try a 2 star alignment with it last night so think I was pretty close to aligned (I know I only need to be a fraction off!)

I'll stick with it tho!

[dph1nm]

Check the direction of the trailing. If it is in the Dec direction then it is PA. If in RA it is almost certainly periodic error. If it is in both then you have both effects!

NigelM

[mbalkham]

Thanks Nigel. It's both! Funny shaped line which isn't clear on the image I uploaded but is clearer on Camera.

[Carina Lass]

some of it may be DSLR mirror flop due to less than perfect stability.

It looks a little hooked at the end which suggests vibration of some sort.

Also could be backlash due to too perfect balance.

Balance should be biased ever so slightly so that the motors are always driving the rig.

When you are pointing east, it should be counterbalance heavy and when west telescope heavy.