Thackeray's globules

[Shiraz]

Hi

Another one - seems to be a popular subject.

Had some really good seeing below 2 arc sec. The moon was up, so decided to image this interesting area at the rear end of the chicken in Ha.

These globules have always been appealing since they stand out so well against the background nebulosity - now to get some colour :). Thanks for looking. Regards Ray

scaled to page width: http://www.astrobin.com/full/96042/0/

full res warts and all: http://www.astrobin.com/full/96042/0/?real=&mod=

Skywatcher 250f4 with RCC1
SX H694 (0.913 arcsec sampling)
NEQ6

5 hours of 5 minute subs, 6nm Ha.

[clive milne]

That is world class Ray...

[clive milne]

No, I take that back... that is superb.
Perhaps your best image yet.

[gregbradley]

That is a beauty.

Greg.

[Shiraz]

Thanks Clive. Your encouragement is very much appreciated. Gosh it was great to get some really good seeing - doesn't happen very often.


Thank you Greg.

Regards ray

[Dennis]

A fascinating cosmic scene Ray - top work.:thumbsup:

Love the overall look, details, wispy structures, curtains of nebulosity and the stark contrast of the darker globules.:)

Cheers

Dennis

[RickS]

Great level of detail, Ray! Looking forward to the colour version.

Cheers,
Rick.

[multiweb]

Sublime. Best I've seen to date. :bowdown:

[Paul Haese]

Very nice Ray. Naturally I compared your image with my full res version (not online). I note that your full res image has next to no noise visible at all and only half the data. I am using 30 minute subs but you are using 5 minute subs. f ratio will influence that though, f8 is very slow and requires quite deep subs to get the ADU up over 1000. 30 minutes gives me 1152 ADU at f8 with the STXL11002.

Detail is very nice and I like your composition too.

[Shiraz]

Thanks Dennis. As you know, it's hard to get the right balance when processing, so appreciate your feedback.


Thanks Rick. was nice to have good seeing for a change - in contrast, just packed up for the night with seeing sitting on about 4 arc sec.


wow, thanks for that Marc.



thanks Paul. Apart from the field of view, I thought the two images looked very similar - but of course I didn't have access to your full res result.

Re the exposure time difference, the optics of both systems produce almost identical photon flux/pixel, so I think that the factor of 2 difference in exposure time is nearly all down to the the 65% Ha QE of the 694 chip vs the 30% of the 11002. The 11002 has about 2.5x the read noise of the 694, so your subs need to be about 6x as long as mine (this scales roughly with read noise squared) - with your 30 minute subs and my 5 minute subs, that is what we actually used. We would both benefit from longer Ha subs though, to keep the read noise contribution as low as possible.

Regards Ray