off axis guiding question

[libraryman]

Hi all, i'm trying OAG for the 1st time, i'm using a qhy5iiL with a qsi 583wsg on an fsq 106 i notice that the stars aren't round as i would expect them to be.

is this normal?

Ray

[Owmuchonomy]

Are you happy with your polar alignment?

[Ibbo!]

yes the guide stars with an OAG can look a bit dodgy

If fact I have guided relatively successfully with seagull shapes and lines

If you can pop the prism in a bit further without showing in your train they should improve a bitr

[D4N]

Also make sure that the face of the prism is square to the focuser, I noticed there is nothing to stop mine being put in at an angle, this gives very odd stars.

Sent from my iPad using Tapatalk

[Earl]

I have noticed oval stars of sorts in my OAG but it is a fair bit further out from the main chip so im not suprised. Its never been an issue.

[ollypenrice]

I'd sink the periscope in till you see the shadow and then back it out again just so the shadow vanishes. You have lots of spare illumination with your setup. This is something you can do in daylight just taking flats (which you won't be using as flats!  )

Olly

[Merlin66]

Which guide software are you using?

[libraryman]

Wow, what good advise and explanations!! Many thanks all..i don't always ask the right question but if you , just goes to show what help is availablelast

Software last night...maxim...

I'll have a look at "dropping the periscope Olly" but to be fair, they did improve after I upped the sub time from 2 to 3 sec and on top of that when I eventually got around to trying it, the atmospherics were terrible.

Loads of moisture in the air...guiding was awful but I was only using it for trying out things....It calibrated o.k but the red lines axis was way of the centre of the star.

Need to now test it on a good night.

Ray

[libraryman]

Another reason dawned on me this morñing, I was running some V curves in Focus Max..,i had forgotten that it would effect the OAG focus, if i wasn't correctly focused on a he main scope...doh!!!

Ray

[orion69]

Star shape in OAG doesn't matter at all.

In fact, focus in guiding camera can be little off.  

[libraryman]

O.k cheers for that Knez

Ray