Stephan's Quintet and NGC7331 in the 14 inch.

[ollypenrice]

Interesting and controversial object because one of the Quintet members has the same redshit as NGC7331 while the others share a higher redshift. So is the Redshift an unreliable measure? So thought Halton Arp.

Edouard Stephan made this quintuple discovery quite near here in Marseille in the late 19th century with a scope made by Foucault of pendulum fame, no less. I can just about see it in our 20 inch Dob. (The Quintet, not the Foucault reflector!)

So, the pic. Yves' 14 inch ODK and SXH36 mono, L 20x15 mins and RGB 10x10 mins per channel, ten hours in all. Alas the focus drifted for the L run while I was busy with a visual group and I didn't spot it. Once again the Mesu Mount 200 'just did it' without losing a sub to guiding. I literally don't remember when I last lost a sub on this mount.

Olly

[fwm891]

Perhaps the focus shifted - but still a stunning image....

[Mark at Beaufort]

Olly I really like the final photo showing the wide field of this area. Its interesting that you need the 20" Dob from your dark site to view the Stephans Quintet just shows I have little hope of viewing it with my 10" Dob. Perhaps I should visit you!!

Regards

Mark

[vdb]

Olly, how the hell did you rescue the L I'm looking at it and I go no can't be,

you little wizard ...

Yves

[NickK]

I think if you use very narrow band Ha (ie 3nm and 12 nm) you can separate the redshift if the velocity is high enough in M81/82 (I can never remember which one is which).. perhaps the same is true here.

[ollypenrice]

Olly, how the hell did you rescue the L I'm looking at it and I go no can't be,

you little wizard ...

Yves

Oh, give it a go. It isn't that bad, honestly. Nothing special here. The key thing was that I did three stretches, one for the starfeild, one for the core of 7331 and one for the fuzzies. If you stretch the stars as much as you stretch the fuzzies there are more stars than background sky! I put the background sky/stars stretch on top of the deep fuzzies stretch, set both background sky values to 24, and used the erasor to let all the little fuzzies through.

I used your methods for sharpening 7331.

The focus drift had split some diff spikes on the L layer so I eased the L on the big stars and just used the better-focused RGB. You have to get the levels right in the RGB layer to do that.

Sorry about the focus drift though. Shame.

Olly

[Gina]

Amazing shot!

[ollypenrice]

Amazing shot!

Thanks Gina but the version with the new L is much better. http://stargazerslounge.com/topic/159265-stephans-quintet-improved/

Olly

[Gina]

Wonderful If only we could have some clear nights! I'm gradually improving my equipment but getting so little time to test or practice the imaging side.

[acey]

Its interesting that you need the 20" Dob from your dark site to view the Stephans Quintet just shows I have little hope of viewing it with my 10" Dob.

You don't need monster aperture for the Quintet - I was able to see 4 of them with an 8" and all 5 quite easily with a 12" at my dark site (SQ 21.3). 12" is enough for pretty much anything in the NGC as long as the sky is dark enough.

[ollypenrice]

You don't need monster aperture for the Quintet - I was able to see 4 of them with an 8" and all 5 quite easily with a 12" at my dark site (SQ 21.3). 12" is enough for pretty much anything in the NGC as long as the sky is dark enough.

It must be my eyes then! I can certainly see it but not easily and our SQM is often 21.7.

Olly

[farunj]

Wow!! That's awesome!! Stunning!!