Orion TOAG star issue

[timtrice]

Posted this on another forum but didn't get much help. Hoping someone here may have a solution...

This is Antares through SharpCap and PHD 2 at focus. View through DSLR is fine.

[Ant]

Is this through the guide cam (via the OAG)?

If it is then it may be slightly out of focus.

My stars aren't round, admittedly they aren't that bad, but they are far from round. I believe it's something to do with the prism in the OAG. I was told a while back not to worry too much about it, as in fact PHD prefers a slightly out of focus star as it's easier to calculate the centre of the star.

Try re focusing and get the stars as best you can with the cam and OAG. See if that improves it.

Attached is a screen grab of my last guiding session, the phd screen is on the right and you can just make out that the stars are very odd.

Cheers

Ant

[timtrice]

This is at max focus through the oag yes. And that takes up about half the image window. Problem is that's Antares. Fainter stars don't show up at all

[Ant]

When you max focus, what do you mean by that?

Is it the best focus you can achieve or the focuser in all the way in out.

Can you use just the guide cam through the scope and make sure that it can achieve a decent star image? At least then we know the guide cam is ok, so it must be an issue with the OAG.

Things I would try.

1. Guide cam only in scope to make sure it's working correctly.

2. Move the prism position slight (move further into light path) to ensure it's not only having something block it.

Is there any pivotal movement in the OAG stalk, I wonder if the prism not being square to the focuser would make a difference (this is only a guess).

Cheers

Ant

[timtrice]

I do know it's not the camera as I used it on the large scope to guide while piggy backing the dslr. I am set up to try and fiddle with it more tonight but my patience is waning. I wanted to get rid of my guiding scope which is less than half the focal length. Plus reduce weight. But this is costing me valuable imaging time what little I have anyway.

By max focus I meant focal point. Plenty of room in and out to go.

[Ant]

Can you contact the vendor and see what they say? Show them what you are getting as it isn't right.

Ant

[timtrice]

I did by email a week ago and hot no response. I called Thursday and the guy said send it in and they'd look. But I'm under 30 days so don't want then keeping beyond then telling me oh well. I had problems with them on my scope prior. I've heard people say they have good service but I've yet to see it

[timtrice]

This issue is resolved. I was catching the star on the edge of the prism. What I have found is if I slew a little bit more then the star shows up perfectly in view. Ironically, I've noticed this happens quite a bit. But when there is a star bright enough to take advantage of the exposure (sorry = not sure how to accurately put it) the brightness of the star dimming the image makes these odd "comet-like" structures disappear.

Nonetheless, all is well now... thanks to everyone who has tried to help.