What is going on??

[adamsp123]

Here is a crop of a frame I took using an Atik 383L+

Now it looks to me that it is out of focus but I focused the rig using a Bahtinov mask it was spot on.

Any ideas what these halos are.

Now I must admit I didn't have cooling set on the camera for focusing but did set it for the subs, so would going +11 to -10C on the camera affect the focus?

Other details scope 120ED with SW120 flattener and AstronomiK 2" IR Filter.

Your thoughts most welcome.

Pete

[RobH]

Whatever the reason, out of focus it is!

I can't imaging the camera temp would affect things, and that looks like a big focus shift.

Did something get knocked perhaps?

Rob

[LukeSkywatcher]

Out of focus. Something happened to knock it out after you had focused it.

[Neil27]

Out of focus.

I'm glad I'm not the only one who is having problems focusing the atik 383...:0) Canon live view has a lot to answer for!

Only other question did you focus on a star around the object you were imaging Peter or did you slew the mount after getting critical focus? That may have shifted it slightly.

[adamsp123]

Thanks all, thought it was focus, I don't remember knocking it but something must of happened.

I focused using Arcturus then slewed to M101 BTW.

Well thankfully it is something simple (oh that's me) so more care next time.

[roundycat]

what software are you using for camera control? Focusing with s/w assist is, in my view, much better than a mask. There are plenty of stars near 101 that are bright enought to focus on if you are using the camera output to focus.

Dennis

[beamish]

perhaps the focuser slipped under the weight of the camera?? Can you lock it off ??

[Mick UK]

Pete, once you achieve focus using your B/mask are you then locking it down with the lock screw?..ive noticed that when doing this it alters the focus.

Try adjusting the tension on your focuser so its quite tight, this will hold the tube firm enough so you dont need to lock the tube with the screw.

[David Galvin]

It it was focused using the mask and locked perhaps the system is suffering from condensation.

[adamsp123]

I have always found the B mask to be very accurate with my DSLR so no reason to expect any difference with the Atik, and it was locked down before checking the focus because I know the focuser moves when being clamped.

Condensation on the CCD would be a concern when being cooled, there was none on the scope optics. I will run some tests, if it is the on board cooling causing dew on the CCD then I would be very very unhappy.

[Neil27]

I have always found the B mask to be very accurate with my DSLR so no reason to expect any difference with the Atik, and it was locked down before checking the focus because I know the focuser moves when being clamped.

Condensation on the CCD would be a concern when being cooled, there was none on the scope optics. I will run some tests, if it is the on board cooling causing dew on the CCD then I would be very very unhappy.

Pete, I had the atik cooling to -20 last night and observed no evidence of condensation. I ran it like this for a good half hour. I managed to even get a few subs of M3, I'll post them if you want, I'm curious to see what they look like as well.

Regarding the focusing I found the supplied software very easy to use and just used the laptop and 'loop' exposure method, but I guess I'm quite familiar with that method.

[Neil27]

OK,

as promised had the atik running at -20 last night and just managed a few subs before the clouds rolled in.

Here is one 4 minute sub of m51, no darks, no bias etc etc, just a light stretch and thats it really.

However noticed a mark on the image which is more evident on the m3 sub, also shows some spots on the image???

Anybody have an idea?

[roundycat]

the smallest spots are probably dust on the chip cover glass. The bigger ones are further away from the chip, the filters perhaps? The dirty great big piece of crud is probably a small piece of hair or similar in the same place as whatever is causing the bigger shadows.

Dennis

[adamsp123]

Sorted - it was focuser slip thankfully.

I focused using my Bahtinov mask last night and focuser well clamped did the trick here are 3 pics

initial focusing on Arcturus - no cooling

then on Alkaid in Ursa Major - no cooling

Alkaid in Ursa Major - cooling on to -18C

Last pic M101 - a single uncropped 8 min sub on a 120ED near the end of the run