Crescent Nebula NGC6888 Blacklands Farm 4 June 2011 00:00-03:00

[The Thing]

HEQ5 Pro, EQMOD, CdC, LX90 8" UHTC Baader Alan Gee II Telecompressor, Canon 350Da, Astronomik CLS-CCD clip filter, Lakeside Focuser, Bahtinov Mask, Dunc's Collimation Mask, Meade 8x50 FinderGuidescope & QHY5, PHD Guiding, APT Astro Photography Tool.

10mm extra spacing was added between the SCT T-thread adapter and the camera adapter. The stars are now lovely and round to the edges. I never thought my LX90 was capable of this even with the telecompressor thingy (which was expensive). Just shows that details are important.

Processed in DSS using two groups. 10 flats and a Master Offset (main group), 5x580s (10 darks), 10x360s (10 darks). Kappa Sigma stacking, kappa 1.5 with 2 iterations. Don't ask me why 580s instead of 600s - I don't know! Probably cider related maths.

Full frame resampled to 1024 X 682 no sharpening. Full Size here (6Mb)

[Fay]

Well, what a great image Duncan, looks as good as I thought it was. Really super!!!!!

[The Thing]

Thanks Fay. I am still gobsmacked by it myself!

[Carole]

That's excellent Duncan, definitely your best so far, and you have some nice colour in the stars as well.

Carole

[mickw]

Said it before, but great image Dunc.

Looks much better without sunlight reflecting off the laptop screen 

[JohnP]

Wow Dunc - absolutely superb - you have definitely stepped up a notch in the imaging stakes.. I can see why you are chuffed.. Very well done indeed. Out of interest what is bright patch bottom right - is it just background neb or something else?

Really an image to be proud of & shame I wasn't there to share your joy when you were capturing it...

John

[RobertM]

That's a really excellent result Duncan, that extra spacer had transformed those stars.  I think you should recheck your flats, it looks like there's comething no quite right there to me.

Robert

[MarkS]

Excellent Duncan!!

Everything looks good about that - the colours are right and there's even a slight green tinge bordering the red.  You've done a good job of processing it, though maybe a little too black in the background.

You must be really pleased with that. 

Mark

[The Thing]

Thanks Mark.

I have tried my hand at PS processing this afternoon. No Noel's Actions in sight! I think I have succeeded in getting the correct colour balance and have brought out a bit of the surrounding nebulosity. Hope I didn't overdo it. A bit of Unsharp mask was applied after a tad of gausian blur to smooth the stars out. I think as someone below mentioned, the flats haven't flattened properly - they are the right files, I checked. The centre looks too bright. Or maybe it's meant to be like that!

Full size image

[Carole]

Hi Duncan,

I think I prefer the original as there is more contrast between the nebula and the sky background, and better colour in the stars.

Carole

[Rocket Pooch]

I prefer the latter because NGC6888 sits in a sea of Ha!

[Mac]

Very nice,

Mac.

[MarkS]

Personally I prefer the original.  I think there is too much red in the second one.

Mark

[RobertM]

I agree with Mark about the red.  Did you use flats?

Robert

[The Thing]

Thank you all for your comments. It is too red, the stars that had a bit of colour have lost it in the second picture. When I get a moment or ten I will see if I can balance the colours better.

As mentioned before, I did use flats, taken at iso100 in AV mode using APT. They look OK, plenty of defects visible, but there still seems to be vignetting evident in the final image. I might see if there is something in DSS that should be used differently e.g. Kappa Sigma stacking rather than median for the flats.