M51 March 2012

[SteveA]

I finally got around to processing the M51 data from a few weeks back, this being the first real images I've captured with the new 250mm f4

Quattro..

The following LRGB Ha consists of;

L = 600 min (combination of 300,600 & 900 sec subs)

R/G/B = 135 min (combination of 300 & 600 sec subs)

Ha = 3 x 900sec

Calibrated and stacked in MaximDL. All processing in Pixinsight.

[Quatermass]

Great job, thats a lovely m51 with bags of detail and colour

[MikeD]

Great result Steve, the Ha has come through well.

Did you process the different length exposures separately or stack them together?

Mike.

[SteveA]

Thanks chaps..

Hi Mike...I actually took all of the different lenght subs and stacked them all together in one run. I've never been sure whether this is the best policy or to stack each set of subs by exposure length...and then stack the stacks. May well give it another a go....

The ha made an amazing difference to this image....it looked rather bland before....This is the very first time I've incorporated Ha....as I only got hold of the filter a few weeks back....I'm very pleased with the investment!

Cheers

Steve

[MikeD]

Hope you don't mind I had a quick play with your jpg in photo shop.

Levels, curves, colour adjustment and some sharpening.

Mike.

[SteveA]

Hope you don't mind I had a quick play with your jpg in photo shop.

Levels, curves, colour adjustment and some sharpening.

Mike.

Hmm...you're right..that definately does look better.

I'm just off to have another play with PI....

As you guessed I'm trying to work this project entirely within PI...just gota work out the right tools to use..

Some of the approaches I've tried just boost the noise..so still some experimenting to do...but thanks for the pointer...

Steve

[ollypenrice]

It really is a nice image and Mike proved it had more to give.

What's the point of the mixed sub lengths? Surely the longer ones would be the best?

Maybe the fast Quattro would cook the core but I'd have a good look to see if it did. Personally I'd be surprised if the core were much different in any of them.

For cores I use a shorter stretch as a Photoshop layer under the full stretch. I like Pix but never in a million years will I use it for the whole job.

Olly

[Gina]

Beautiful

[Lynxi]

Beautiful image both the original and Mike's new image from photoshop. Beautiful

[SJJ]

Great image, you really captured the star forming regions in the galaxy.

[Jessun]

Wow!

I look at my OSC now with more and more doubt... This is seriously good. Some phenomenal gigs of data!

[SteveA]

Thanks for all your comments...

I ended up with a selection of various sub lengths for this image as I was really pushing them to see how far I could go without getting to many LP issues.. I was really quite suprised I could get away with 15 minute exposures...and I just couldn't face ditching the shorter subs..so I stacked the whole lot together. I'll obviously have to bear this in mind for the next project.

Also..confession time!.....I've never really got to grips with Photoshop! I know I need to invest some time getting to grips with it....but up until now I've spent most of my efforts finding my way around PixInsight....

I've had another play with PI...I think I've extracted a bit more out of the image here..and I found the Unsharp mask...which has made a fair difference....thanks again for your comments

[ianaiken]

I really like that last revision you've done. Great work!

[Anweniel]

Striking colours in there and a fabulous amount of detail. Personally I think you are going for a touch too dark a background colour and I must admit I prefer the more natural appearance of the original and the one Mike tweaked but thats a personal preference.

[SteveA]

Striking colours in there and a fabulous amount of detail. Personally I think you are going for a touch too dark a background colour and I must admit I prefer the more natural appearance of the original and the one Mike tweaked but thats a personal preference.

You are totaly right!

I loaded this jpeg up on my PC at work to print it off...and it looks "nasty"....Mike's tweak is certainly MUCH better....

I'm going to have to learn photoshop!

[Quatermass]

check out my blog for a set of photoshop tutorials to get you up and running learning photoshop is fun but it does take a while start with levels and curves and then the rest will follow also tons of links to more tuts on the forum in imaging

Sent from my GT-S5670 using Tapatalk

[SteveA]

Thanks for that....

I must admit I've been trying to avoid PS as it looked to difficult...having said that PI wasn't exactly straight forward either, but I found Harry Page's tutorials so good they really gave me a flying start and I've got a fair way just using PI.

Thanks again..

[Gina]

It still a wonderful image

[Anweniel]

Its definitely a very nice image I think colour vs detail can divide camps a little and certainly processing is a very steep learning curve, must admit I would be happy if I had produced any of the pictures you have displayed here SteveA!

[SteveA]

Having not ben able to get out over the last few weeks I've had to make do with playing with this image and try and improve on my first processing attempt. MikeD gave me a few pointers for processing in Photoshop, but I've decided to stick with PixInsight and I think I'm slowly getting the hang of this now.

For this latest attempt I went back and processed both the Luminance and RGB channels again, I think I've got a better colour balance this time around.

I also used the Atrous Noise Reduction routine...which seems brilliant at reducing a lot of the noise I was getting in the background.

I may stick with this...but if the rain continues for much longer I may have no option than giving it another go!

[MikeD]

Excellent result, colour looks great.

The only thing I would say is be careful how much noise reduction you use, some times a little noise is better than an over smooth image it can start to look a little unnatural.

Great stuff.

Mike.

[Jessun]

Wow! I like this one Steve! If I could say something based on what my screen shows then I'd suggest looking again at the red channel in the background, and perhaps take it back a notch. Then I'd ease back a bit on the star saturation - red and maybe blue too.

Then I'd just sit back and admire.

[SteveA]

Thanks guys....

Can some one explain something here....

I posted this image from a desktop PC I use at work....and viewing it on SGL..on that PC the result looked absolutly fine. I'm at home now and using a laptop..the image I see looks frankly awfull..the background looks awfully noisy and I can understand Jessun's comments.

Is it just me...or do you all get these different results on different monitors ?...is there something I'm missing ??

[Jessun]

Steve,

For starters all monitors are different until you calibrate them with some professonal or semi professional tool. What you can do though in for instance PS is to use the Colour Sample Tool to see what actual pixel values you get for your background in this case. This tool will not lie, and will give you a readout of true pixel values, and I would guess that yor latest M51 rendition will show a higher red count.

Then when you are all happy to chuck it to SGL, the forum software itself will do a jpeg compression that alters your image a tiny bit, so one way to get past this is to host your images remotely, on FLICR or similar. At least then you know that your image is presented in the best way possible.

Having said that, a jpeg compression shrunk to half or a third of the size often shows gradients and other problems that you didn't really pick up before so in a sense it's quite useful!

[SteveA]

Yep...You are correct.

The histogram looks like this..clearly the red channel is stronger.

I noticed this through the processing..but the image on my screen looked OK at the time....Looks like I'll need to goback to the drawing board on this then!

I'm reasonably sure that this inbalance must have been down to bringing the Ha into the image...does that sound reasonable ?

Thanks for the feedback....

Steve