Ngc3621

[Shiraz]

got some new data on NGC3621 to be added to that from last year (I was somewhat disappointed with last year's effort). Rejected the subs with poorer seeing - 62 of them - so nothing above about 2.6 arcsec FWHM was kept (as measured by PI) and some of the subs were down below 2 arcsec. The resulting stack of 200 subs (mix of 4 and 5 minutes) was very easy to process - mild deconvolution, stretch and background flattening. I think that quite vigorous pruning of data pays off and, where it makes sense, will be doing so more aggressively in future.

full resolution (sRGB gamut) at : http://www.astrobin.com/full/240618/0/?real=&mod=

thanks for looking - I think that this subtle beauty is among my favourite objects. appreciate any comments/advice. Regards Ray

[Atmos]

Fantastic job Ray. The main galaxy looks wonderfully resolved, numerous background galaxies too :)

[TR]

Vigorous pruning in the garden pays off as well. That is a very nice result Ray.

[RickS]

Lovely, Ray! A great improvement over your previous rendition which wasn't too shabby either.

I have been weighting my subs on FWHM and trying to keep as many as possible. It's so hard to throw data away :)

Cheers,
Rick.

[alpal]

Hi Ray,
That's perfect.
It's really sharp & clear.
The 10" f4 does it again - Well done.

cheers
Allan

[PRejto]

Really nice!! I love that little face on spiral at 11 o'clock. This is an inspiring image. Great!!

Peter

[Placidus]

Technically superb and a pleasure to explore.

[Shiraz]

hi Colin. thank you. yes, the background galaxies are quite a varied lot in this region.


thanks Terry - getting rid of the lesser subs seems to be beneficial overall.


Thanks Rick. I am coming to the conclusion that once the low res stuff is included it cannot be unscrambled effectively. I also hate throwing away data - am doing a lot of thinking about how to re-include some without stuffing up the good bits.


thanks very much Allan. yep, the optics seem to be pretty good (thankfully).


thanks very much Peter. Yes, that spiral is a handsome galaxy - need some more resolution....


thanks M&T - very much appreciated

Regards Ray

[multiweb]

That's a beautiful field Ray. Love the colors. Some very good details in the spiral structure. I also like that little face on at 10 o'clock. Good stuff. :thumbsup::thumbsup::thumbsup:

[Shiraz]

thanks very much Marc. that small spiral sure is a beauty.

[Stevec35]

Great job Ray! A pleasure to view.

Steve

[tilbrook@rbe.ne]

Wonderful image of NGC3621 Ray!:thumbsup::thumbsup:

200 subs 62 rejections, damn perfectionist!!:)

Always a pleasure to view your images.

Cheers,

Justin.

[Geoff45]

That's a great image Ray. It's a really difficult target as I found from personal experience.

Pruning is hard at first, but I found that once you get into it it gets easier and the result justifies any angst about rejection.
Geoff

[rustigsmed]

awesome, loving the outer arm extensions - nicely done!

Russ

[Shiraz]

thanks very much Steve.


Thanks Justin. nope, not a perfectionist - just annoyed that I cannot do better.


thanks Geoff. It's a beautiful object, but the dim bits are hard to get. Removing sub-standard data helped, even though it does hurt to throw away 5 hours of photons.


thanks Russ, appreciated.

regards Ray

[strongmanmike]

Another really nice galaxy image Ray, although faint its a very magestic galaxy, an enjoyable view :thumbsup: throwing lots of data huh?..show off ;) :lol: but in the end good seeing always beats processing.

Mike

[Shiraz]

thanks Mike. It isn't often that I have enough data that I can throw stuff away, so I wanted to try out some fairly heavy culling. I haven't done a side-by-side comparo, but my impression is that the culled data produces a better image than the whole thing + heavier deconvolution. Of course, the extremities of this galaxy are very faint, so there may be value in Rick's method of adding in lower res data with lower weights.

As you say, nothing beats good seeing - and there hasn't been very much of that just lately.

regards Ray

[Paul Haese]

A very nice image Ray. Colour balance looks near perfect to me. The smooth background is also a nice addition to the image. Well done.

[graham.hobart]

Another beauty Ray.Inspiring stuff!
Cheers
Graham

[Shiraz]

thanks very much Paul - appreciated. The outer reaches of this are dim and it needed more data than normal to retain the full detail in that part of the image.



thanks a lot Graham!

regards Ray

[gregbradley]

Great image as usual Ray.

I would agree using the rejected subs as a separate master and mask in only the faint bits is a possible use.

I also agree culling bad seeing subs does pay dividends. It helps when you are imaging 10 inches at F4 with 77% QE.

Greg.