NGC 3718 now in LRGB

[DaveS]

I've been fighting this for a couple of weeks now, but feel able to post

I took 15 subs of Red and Green, plus 27 Blue and 31 Luminance each of 10 mins. Stacked in DSS with full calibration then imported into AstroArt for assorted Histogram stretches, DDP, and Gradient Removal. The Luminance was also given a masked Unsharp Mark for the galaxies.

There is a streak of light from a bright-ish star just outside the frame which I've deliberately left in.

It's nowhere near perfect but will do until I can get proper G2v calibrated data next year, this had to make do with more subs, rather than the longer ones which would have been better.

[geoflewis]

David, it is a really fine image. Stars are nice and round and it's pretty deep with the galaxy tails showing well, together with lots of other faint fuzzies to be seen, in addition to the Hickson 56 group.

[DaveS]

I had another go since geoflewis pointed out a slight misalignment. I also put a mask over the galaxies and gave the background a denoise to clean it up a bit. Not sure how much difference it's made.

[geeklee]

Great stuff @DaveS  Those tails are really coming out, even the fainter ones curling back on themselves.

Edited May 12, 2021 by geeklee

[geoflewis]

12 hours ago, DaveS said:

I had another go since geoflewis pointed out a slight misalignment. I also put a mask over the galaxies and gave the background a denoise to clean it up a bit. Not sure how much difference it's made.

Hi Dave, to my eyes you made quite a difference. The background is smoother, the galaxy tails are more prominent and the slight channel misalignment previously seen in some of the stars is corrected. Very nicely done

[DaveS]

I did have another go at this, but while I think I've brought a bit of colour into the tidal tails the alignment looks worse.

I can see a touch of orange / green gradient in the brighter stars, but am having trouble getting rid of it. Possible the saturation is too high.

[DaveS]

Had a final bash at this using the Coregister function in AstroArt 7 instead of a simple align as that can deal with a slight lateral chromatic aberration. Plus the masked unsharp mask and masked denoise after assembly.

Dunno, think it's in the region of diminishing returns until I get a shet load of new data next year.

[geoflewis]

13 minutes ago, DaveS said:

Dunno, think it's in the region of diminishing returns until I get a shet load of new data next year.

Probably true from here on in, but this latest version was definitely worth the extra processing. Very nicely done David.

[peter shah]

Thats pretty deep Dave...great work

[DaveS]

10 hours ago, geoflewis said:

Probably true from here on in, but this latest version was definitely worth the extra processing. Very nicely done David.

Thanks Geof. Looking forward to getting more data next year, fingers crossed.

9 hours ago, peter shah said:

Thats pretty deep Dave...great work

Thanks Peter. An extreme stretch shows more faint tidal tails but too buried in noise to be worth leaving in the image.

Maybe with more *better* data I'll be able to get some colour in the tails.