Beautiful spiral galaxy M74 revised

[gregbradley]

210442This one has been on my to do list for a while ever since I got some nice preliminary luminance data about a year ago.

I took this with the CDK17 and Proline 16803 a while ago and just finished processing it.

10 hours Ha LRGB all 10 minute subexposures.

http://www.pbase.com/gregbradley/image/164834002/large regular size image

http://www.pbase.com/gregbradley/image/164834002/original large size image

Greg.

[RickS]

Very pretty, Greg. Is the mottled appearance of the outer halo on the right hand side a processing artifact? I haven't noticed it before but then I haven't looked at a lot of images of M74...

Cheers,
Rick.

[strongmanmike]

Oooh Greg :question:...did you process this on a different monitor or lappie perhaps...? There are pretty obvious processing artifacts in a ring all around the galaxy, the main part of the galaxy is really grainy and the background is unnaturally smooth in comparison. Sorry to sound critical but just being honest, I am sure there is a good image in that data and I love this galaxy but ya've kind'a made'a mash of it dude :shrug:...sorry. The Ha regions are standing out nicely though :thumbsup:

....try again?

Mike

[Atmos]

The data looks very nice, quite a number of faint galaxies poping out through the background and M74 appears to be very nicely resolved. Ha is showing up nicely.
I do agree with the others though, the outer halo looks overly smoothed causing a blotted appearance.

[astroron]

I am glad the other more experienced imagers saw what I saw,
I thought it was my computer,but when I went to the links for higher res it was the same.
I too have never seen that sort of mottling in this galaxy.
It doesn't look natural.
Cheers:thumbsup:

[Cimitar]

Love looking at those faint background galaxies Greg, very nice :thumbsup: M74 also makes a great contrast.
The core looks good, agree with other comments RE: mottled appearance in the outer regions.
Cheers, Evan

[gregbradley]

Thanks Rick I pushed it too hard and was trying out a new piece of software and as usual with image processing a little goes a long way and I went too far. I fixed it easily enough though.



Thanks Mike. I've done it again and its more natural. I pushed it too hard and didn't leave enough time between viewings to get a fresh look where these things show up easily.





Thanks Ron. I fixed it up.



Thanks Evan, Yeah I fixed it up. Pushing the data too hard and the little faint outer halo starts to mottle but I believe it is real data, just not enough exposure to show it solidly.

Greg.

[astroron]

Thanks Greg, Much nicer.:)
Cheers:thumbsup:

[strongmanmike]

Still a little mottled in the outer arms but that looks much better now Greg :thumbsup: ...probably just needs more exposure to get those outer arms showing properly, 190min L is a bit thin and was that just one 10min sub for the Ha? Looks like you have some nice detail going on in the inner regions though. It's a magnificent galaxy, love the tight inner core spiral!

Overall, an enjoyable view :)

Mike

[strongmanmike]

Hey Greg, the luminance only (http://www.pbase.com/gregbradley/image/164828258/original) looks good

:thumbsup:

Mike

[Placidus]

Yes, the luminance looks great. Lovely detail in the core. Very nice.

[gregbradley]

Thanks Ron



Yes the luminance is the best data. Limited time, limited weather so you work with what you got. I don't mind th small amount fo mottling which on my monitor at least is quite subtle now, rather than without it and the overall galaxy loses some of its extent. A processing choice. Perhaps if I get the time I can present one not as pushed.



Thanks. M74 is a bit of a dim galaxy so probably not the best target if you have limited time and weather but it has such a nice form to it I couldn't resist.



Cheers Mike. I am not sure how the earlier version got through. I usually double check it. Perhaps a setting on my monitor (I often set it to eye saver as I find this monitor hard on my eyes and that changes the colour).
The remaining mottling on my monitor is very subtle and I wanted to push it to show the extent of the arms not normally seen. But perhaps its better to not do that and make sure what is shown has no shot noise.

Greg.

[marc4darkskies]

Probably not enough data for this object but it's a very nice result Greg! :thumbsup:

[gregbradley]

Thanks Marcus. I may do another version that isn't pushed so hard. But year time was limited and weather limited added to the fact its not a particularly bright galaxy. But it is pretty! I intend to mainly use that setup for high res brighter objects in the future. It seems to do best with that.

Greg.

[gregbradley]

Here is an alternate version which is not pushed much at all.


http://www.pbase.com/gregbradley/image/165013534/original

Here is the original:

http://www.pbase.com/gregbradley/image/164834002/original

Which do you prefer?

Greg.

[Atmos]

Can I be a pain and say I prefer the inner part of the old and the outer part of the new :P

[gregbradley]

Hehe, sure. There's always some aspects of an image that turn out better than another version.

Greg.

[Stevec35]

The alternate version wins it for me Greg. More data would help of course but it's still a pretty good image of a difficult object. I've never been game to attempt it myself.

Cheers

Steve

[gregbradley]

Thanks Steve. Yes more data would definitely smooth it out and bring out those outer arms without so much digital stretching which is always risky.

Its a bit dim so I think I will concentrate on slightly brighter targets as I have limited weather/time for that setup.

Greg.

[Shiraz]

the galaxy looks lovely, with nice colour and good definition of the ha regions. To me, the slight mottling of the background is more acceptable in the less-pushed one, but I still prefer to see more of the dim bits, as in the original.