M51 Whirlpool Galaxy

[Darth Takahashi]

The weather was nice and clear on Wednesday so I setup to image the Whirlpool galaxy M51. Setting up cost me 10min, Calibration another 15min and finding M51 another 15mins.

By the time I had M51 centered and ready to go the clouds rolled in and it was already 0:30am so I called it a night.

Thursday same process expect this time finder and placing M51 in the center of the frame only took 2-3mins. Also I was read to image by 22:45pm.

First run 10x 4min subs @ ISO1600

Second run 7x 10min subs @ ISO800

No filters were need because M51 was very high, close to the zenith. Seeing was good and transparency was average. Like so many I also suffer with water vapor in the atmosphere, nothing 1000m elevation wouldn't cure

Camera 450D (Kiss 2X)

Telescope Mewlon M250 with reducer

Guide scope FS60C

Mount EM200 USD3

This is just about the maximum payload that my mount can accept. If I try to use the Sky90 to guide its already too heavy

I'll try some more processing whilst on holiday visiting family in the UK.

I had another play with the image, can't quite decide which is the best technique for stacking galaxies, Median, average or Sigma clipped etc... What do you think?

Neil.

[Dangerous-Dave]

Shame to see this one sink without comment. Terrific work Neil - wish I could get a capture of this galaxy like that. A bit of a cyan cast in the arms - if you hadn't mentioned you used no filters I'd have guessed this was due to a CLS filter.

D

[Aza]

Nice image Neil. Personally I use sigma stacking. I am not exactly sure but I think this should only be used with a fair few subs, although I am not sure of the recommended amount. I always seem to have tons of subs as I go for hours.

When I stack with DSS it gives the recommended settings to use for stacking based on number of light frames, have you tried that?

[Darth Takahashi]

Thanks for the comments guy's;

1. I didn't use a filter at all with the capture this M51 was so high in the night sky. However, I think I have been a little heavy handed with the processing. Using the Mewlon does give my a large illuminated field and so after stretching the image I have to deal with viginetting etc...

2. I had 10*4min sub's and 7x10min sub's. I have tried all of the stacking setting in DSS. I don't like the simple average and the three I try are as followings in order of preference;

A, Sigma stacking

B, Medium stacking

C, Sigma kappa stacking

To deal with the viginetting I use dust & scratches in PS, then clone stamp to get rid of M51 and then finally use this as a difference layer for the image, kind of a lazymans flat! If there is a better technique I'd appreciate the advise?

Neil.

[Aza]

Have you tried Gradient Exterminator?

It costs, but is well worth it, I use it on every image I take.

There is a free trial too:

GradientXTerminator

[ollypenrice]

Good effort! Have you tried something like DDP to preserve a bit more of the core?

Olly

[Darth Takahashi]

Good effort! Have you tried something like DDP to preserve a bit more of the core?

Olly

Whats DDP Olly? Probably a stupid question but I have honestly never heard of it, at all?

Arran, I'll try GradientXTerminator tonight, never paid for astro software yet but will give this a go on your recommendation, well let's see if the trial works first.

Thanks for the tips

Neil.

[RobH]

Nice image Neil, very good tight focus....lots of detail showing.

Gradient Xterminator is a 'must have' if you're an imager, and it's not expensive.

Cheers

Rob

[barkis]

You have a real nice Image after the hassle to get started.

It looks quite good as is, but good luck with any tweaks you do.

Ron.

[Aza]

Go for it Neil, its money well spent. Also get Noels Astro tools if you dont already have them! These tools make images a hell of a lot easier to process!

[Darth Takahashi]

Gentlemen;

After a quick play I have come up with the attached image. The gradientXTermiator worked very well and is definitely a keeper. Also Noel's actions helped in finishing up some of my other minor issues. I still have a lot to learn with image processing but a think the attached image looks more natural now. It was certainly a lot easier to produce, thanks for all the help.

More playing is require but its getting there I think!

Neil.

[doat1]

wow that is absolutely stunning, man i love the universe.

[Aza]

Good job! Thats much better

Glad you found the tools useful, they help no end!