M20-Trifid Top.

[Babalyon 5]

This is addictive. Maybe one day I'll be able to afford an SBig and a better scope, cant imagine what I could do with them!
Triffid top in LRGB, 5x2min exp ea, LXD55 SN10, DSI Pro 2, captured in Envisage, guided with an Orion 80ST, DSI Colour and Envisage.
Stacked and tickled in Photoshop CS2.

[renormalised (Carl)]

I can imagine what to do with a big scope and an SBIG camera!!!

Nice piccie....talk about vivid colours!!! Only one minor thing, your guiding looks a little off as the stars are slightly egg shaped.

[Babalyon 5]

Do you think its guiding? Mmmmmm! What do I do to correct that? I actually think its got something to do with internal temperatures in the scope. Before I start, I put a fan on to cool it down & the stars seem nice & round, however, it cannot be focussed well until you turn off the fan. Then after a while it tends to produce these stars. I wanna get an EQ6 Pro which is better than the 55 mount for the weight of the scope and see what happens. It also seems to get worse the more the scope gets vertical to the ground, but like I said, small mount big scope. Dunno, but I'll keep saving.

[renormalised (Carl)]

It's definitely guiding...problems with temp will introduce noise into your piccies but not wonky stars like those ones. Unless, of course, you have a marked temp gradient between outside and inside the tube, in which case you'll get tube currents which will screw with your viewing and imaging. Make sure you let the tube cool down to ambient (or close to) before you start imaging. I'd say, though, from your description that it's the mount....you do need that EQ6, especially after hanging off the scope a CCD camera, guidescope and all the attending bits and pieces. Your scope has to be as close to rock steady as it can be. For that you need a mount that's going to give that sort of performance, a good heavy, robust one. Then you can worry about getting really good polar alignment...which you will need to produce pinpoint star images over long exposure/guiding times.

[gregbradley]

I agree, tracking errors. Coma radiates out from the centre with stars near the corners being elongated yet round at the centre of the image.

Not sure what temperature problems cause stars to look like - I imagine blurry as it would be more random rather than a drift in one direction.

Guiding errors are using elongated stars over the whole image.

Sometimes it can be all stars look like double stars when the guider goes way off track for a minute and then settles down.

The problem with the Alt Az mount is the Periodic error of the gears - it is very high. Try Periodic error correction if your mount has it that will help. It is a recording of the errors which repeat as the worm gear eventually does a full rotation after something like 8 minutes depending on your scope.

Greg.