Obscure barred spiral NGC 922

[rogerg]

Hi all,

Several days ago this one caught my attention when I spotted in survey images captured the night prior, so I set about getting more data on it.

I, as always, have really struggled with the LRGB and hence here is only the Luminance. The LRGB just looks awful. No amount of DBE or other processing in PixInsight, CCDStack or Photoshop seems to get a flat background let alone have any colour at all in the galaxy its self. :bashcomp:

I can only image it for 2.5 hours before it's set behind my west horizon, and for that time it's in the bright light pollution of Perth.

Anyhow, I really feel like getting something for 3 nights effort so here's the result so far :)

10 x 600s Luminance
ST8-XME
12" SCT @ 2180mm
0.85"/pixel
Shown here at 1:1, cropped.

The galaxy measures about 98.6 arc seconds x 97.75 arc seconds by my measurements, and has a small "tail" extending to the bottom right of image out of that. It's apparently 150 million light years distant, if you believe wikipedia (http://en.wikipedia.org/wiki/NGC_922).

Have I done OK so far?

I will continue capturing data when able in the next few nights to see if more data will save the RGB components. Currently I have 10 x 300s for each of RGB at bin 2x2.

Regards,
Roger.

[RickS]

That is an obscure little critter. Nicely done, Roger!

[strongmanmike]

Of course you have done ok Roger :thumbsup: that's a small galaxy and you are showing some nice detail in her, LEDA says she is 1.93' X 1.55' . I saw this one in my survey for galaxies to image and thought it looked cool but a tad too small on its own like that. That certainly looks like an umbrella like tidal stream sort of thing protruding from it..? You must come across many interesting galaxies in your survey work

Mke

[alocky]

Fascinating - that extension to the lower left looks a lot like the 'umbrella' of ngc 4651. Tricky stuff at those focal lengths - nice job!
Don't know why you're having trouble with rgb combination, I suspect you hold yourself to a higher standard than most, but I'd be happy to show you how it can be done reasonably consistently in pixinsight.
Cheers,
Andrew.

[rogerg]

First a correction: Tail is bottom left not bottom right. I always did get my left & right mixed up :)



Thanks Rick, and for your offer.



Thanks Mike. Interesting to read about the umbrella tidal stream idea. Wikipedia does say NGC 922 likely had a collision with another galaxy 300mly ago which matches that idea.



Thanks Andrew. Once I get some more data (probably total of another two nights) I'll share a dropbox link for anyone interested and see what advice I can get. Of course you'd be welcome to drop by too but don't expect that. You are probably right that I hold myself to higher standard.

I am now wondering if I will get any colour unless I introduce Ha. Don't have a Ha filter. Looking at the hubble image on Wikipedia the galaxy is very neutral in colour if you ignore the bright pink blotches of activity which I presume would have been imaged in Ha or such by Hubble.

[tilbrook@rbe.ne]

Great work Roger!:thumbsup:

Certainly an obscure one, fascinating structure.
Good work getting detail from such a small target.

Cheers,

Justin.

[allan gould]

Nice work Roger especially for such a small object as you are getting some detail there.
Allan

[gregbradley]

That's very interesting Roger. That hammer formation looks just like NGC1097.

Greg.

[Ross G]

Great capture Roger.

A new object for me.

Ross.

[David Fitz-Henr]

That's a challenging object Roger and you have done well to capture the detail within such a small scale.

[Stevec35]

You're definitely going okay so far Roger. I would try and get a lot more luminance though. It should look nice with 2x2 RGB.

Cheers

Steve

[rogerg]

Thanks everyone for your messages of support, much appreciated.

I had another run last night so am slowly building up the LRGB frames.

I have significant flat issues with my RGB for some bizzar reason, a rainbow. I'll post some data once I have more frames. The same happened with the second object I'm imaging each night, so I know there's something amiss with my 2x2 reduction frames (RGB being 2x2) or with my RGB processing.

I'll update after another night hen I will have 20x600s by that stage.

Regards,
Roger.

[astronobob]

Thats a faint little bugga Rodger, Id never attempt it, tooo difficult for this duck !
Mighty fine details in the Object tho, well done & good stuff :thumbsup:

[rogerg]

Hi all,

I have been continuing to collect data on this obscure barred spiral. I now have 240 minutes of luminance data and a significant amount of colour data. The colour frames are still problematic and require more time to process.

Attached is a revised luminance showing increased detail. I'm happy with the improvement in SNR allowing me to push the detail some more but I am not getting significantly more information showing (I think) and so further exposures would have low return on investment I think.

Improved?

PS. Resized this one up 120% because it looked like it could handle it, and show the detail there without having to use a magnifying glass :)

Regards,
Roger.

[RickS]

Yep, definitely more detail now.

[rogerg]

Thanks Rick. I'll have another crack at the RGB data today and make it available to others for processing presuming I fail in my attempt. Thanks for your offer.