Arp 93 - faint features in the tidal tail

[Placidus]

NGC 7284 and 7285 are two small galaxies (each about 2.5 by 1.5 min arc), middling faint (each mag 12, 13 mag/sq arcmin), so difficult targets, and not often imaged, but interesting because they are tearing each other to shreds.

Aspen CG16M on 20" PlaneWave. Lum 9.5 hrs, RGB 2 hrs each in half hour subs. Field 0.36 min arc, north up. No moon, but very windy and variable seeing.

The thumbnail is a tight crop. The full image, which contains many other interesting furry creatures, is here (https://photos.smugmug.com/Category/Astrophotography-at-Placidus/i-6cZ86qr/0/e46ac3a4/O/Arp%2093%20L%2019h30m%20RGB%202%20h rs%20each.jpg).


There are only two other comparable images that we could find: a recent and beautiful work (http://iceinspace.com.au/forum/showthread.php?t=161683&highlight=arp) by Mike Sidonio, which is extremely sharp, and a quickie by the Carnegie-Irvine (https://cgs.obs.carnegiescience.edu/CGS/data/images/NGC7285_color.jpg) Galaxy Survey using a 2.5 metre scope in Chile, which is ridiculously sharp but not very deep.

Our image is much deeper than the CGS image :D, but of course nowhere near as sharp. We're pleased to see that our colours are comparable, and that we don't seem to have produced too many dots that aren't also in the CGS image.

In our image, the broad tidal tail toward 7 o'clock proves to be leaf-shaped, with three identifiable bluish vein-like streamers of star formation, not easily photographed because of their faintness.

Very best,
Mike and Trish

[Peter Ward]

Suspect the seeing let you down, but love the depth of the image. :thumbsup:

[willik]

A little bit out of focus but still a very nice image not a easy target
Martin

[strongmanmike]

Great stuff guys, never before seen on IIS and now twice in under a month :P

Very interesting to compare our results actually, looking at the more diffuse extensions there is little or no difference in depth but as expected, the superior aperture has snuck just a little deeper on point sources...although, I don't apply decon to my star fields so there are probably some faint stars lurking in the background of my data?..I just hate spots in my background that you can't distinguish form stars:lol:. Comparing the detail in some surrounding galaxies I may just have had a little better seeing?.. oooor, we just used different processing approaches..? As you say, you look to have revealed some detail in the leading (left) edge of the main fan shaped tidal tail, which although subtle is indeed very cool. I am thinking from the look of the rest of the image, you used some solid extraction techniques here..? which is also cool, I love heavy extraction to go deep and reveal new things! :thumbsup:...image noise is overrated!

Overall another great use of a great instrument guys and great to see big high end equipment hitting interesting things, rather than the same ol samo :)

Mike

[RickS]

Great work on the faint stuff, M&T :thumbsup:

Cheers,
Rick.

[Atmos]

Comparing all of the different versions... they’re all pretty awesome in their own rights :)
Very nice shot M&T :)

[Placidus]

Thanks Peter. Seeing was so bad on one night (about 3.5 sec arc) we gave up in disgust. It was blowing such a gale that we were worried about the structural integrity of the open flaps on the dome.



Thanks Martin.



Confession: Trish was most impressed by your image, and strongly suggested that we have a go. Yours is clearly much sharper. Some of that is seeing. Some of it is perhaps that you have a superb instrument and we have a light bucket.



Thanks Rick!



Thanks, Colin. Perhaps we should have tackled this in the dead of Winter, when seeing tends to be better.

We suspect we're going to have to go off air very shortly. We suspect the seal on the camera chip chamber has failed, and we are getting ice crystals forming. Every night is worse than the night before. :sadeyes:

[RickS]

My U16M has done that twice now. Class action?

[gregbradley]

Fantastic image. Great to see such an interesting pair of galaxies imaged so well.

Greg.

[marc4darkskies]

Yep, shame about your conditions but the depth is marvellous! Nice work.

[Stevec35]

That's a nice deep image guys

Cheers

Steve

[multiweb]

Very deep Mike. Love the colours too. :thumbsup:

[Placidus]

Thanks Greg.



Cheers, Marcus. We agonized about the one but were pleased by the other.



Thanks Steve.



Thanks Marc. We might have expected from the seeming vigor of the interactions that there would have been yet more intensely blue patches in the spiral arms, but it didn't want to come out that way.

[atalas]

Nice shot guys.