Updated - IC405 Flaming Star Nebula - 26 Nov 2011 02:30 - Rother Valley Campsite

[The Thing]

I have had another go at this. Same framing courtesy of APT. 20x300s from the backgarden in Beckenham last Sunday night (it was so clear and dark). Processed in Iris and Photo Filtre. Binned x2 in IRIS. I hope my processing is getting better. One change, an extra 2mm in the spacing of the FR from the CCD. Unfortunately it doesn't seem to have improved the star shapes in the corners.

Full size here

[MarkS]

Sunday night was certainly one of those very rare nights!

Your latest version is easily as good as the Rother Valley version and you've done a good job of processing it.  It's an excellent result from Beckenham. 

As for star shapes, you are seeing the typical SCT distortions - I don't think changing the corrector spacing will much much difference.  I myself did many experiments with the Alan Gee and got results very similar to yours.

Nice one.

Mark

[mickw]

I think I prefer this version to the Rother Valley one.
There's a lot more contrast in the detail

[RobertM]

I agree with Mick, there's a lot more nebulosity and detail showing plus you've lost the river effect of the first.  Could be the bad stars in the top left are a result of collimation - was it spot on ?  Collimation will be even more critical with these reducers because of the spacing requirements and the large chip you're using.

Robert

[Fay]

you did well there Duncan. especially being local, probably because of that rare night

[The Thing]

Thanks everyone. Next time I do this object I will rotate the camera to get more of the pretty bits in! The asinh colour stretch in Iris is great and Photo Filtre has a 'Revive Colours' function that did just that!

Q. I have 12 more subs taken after a meridian flip - is the best way to combine then to process them separately and add the final image to the first?

Could be the bad stars in the top left are a result of collimation - was it spot on ? 

The scope was freshly collimated. I am tempted to disassemble the secondary holder as this scope is terrible at holding collimation, one screw particularly seems to always require a lot of adjustment. I have a sneaky feeling that the scope looses collimation during an imaging run as the first subs look better in this respect than the last.

[MarkS]

Q. I have 12 more subs taken after a meridian flip - is the best way to combine then to process them separately and add the final image to the first?

I would do the calibration (pre-processing) on them then rotate them before using them as part of a single stack with the others.

Mark