Whirlpool Galaxy

[Iem1]

Afternoon guys,

I imaged M51 last night and managed ~x75 60 second subs, unfortunately I took a risk and tried to see just how stringent I needed to be with dithering to minimise the amount of time spent out in the cold/dark. I set a timer to manually dither every 25 minutes whilst shooting 1 minute subs, and if nothing else, I have learnt that is not enough to fend off walking noise  

So, after trying to save the image from both walking noise and what seems like a familiar light leak in the exact same position it always randomly appears in;

Heavy Crop (trying to run away from worst of light leak);

 

 

 

full size image

 

 

Really kicking myself for dithering less! But I am going to try and add more data, see if I can dilute the first 1 hour of data with properly dithered imaging sequences to phase out all that noise. The light leak is much more manageable in comparison.

I did take flats, but perhaps not well enough on this occasion.

 

But all issues aside, what a beautiful galaxy and DS target to image! I was also amazed at all the other galaxies I picked up in the image (barely indistinguishable from stars!)

Equipment used: WO Z73 430mm, Canon 600D, EQ6-R Pro, 60 second subs ISO 800 (unguided, looking at adding guiding very soon!)

 

The untouched tif if anyone wants to have a look, fairly tough to get an image from it given all the issues!

result.tif

 

 

[Felias]

Thanks for sharing. I'll go for galaxies the next night out (whenever that happens) with my Z61, so I thought I'd practise my new workflow with your image. I did the colour calibration and gradient elimination in Siril, then stretched it in Photoshop. It's true that there was a lot of noise, but working carefully with successive asinh stretches I managed to prevent it from dominating the background. A pass with the PS raw filter got rid of the remaining red pixels, though perhaps it's now too dark a background...

[Iem1]

23 hours ago, Felias said:

Thanks for sharing. I'll go for galaxies the next night out (whenever that happens) with my Z61, so I thought I'd practise my new workflow with your image. I did the colour calibration and gradient elimination in Siril, then stretched it in Photoshop. It's true that there was a lot of noise, but working carefully with successive asinh stretches I managed to prevent it from dominating the background. A pass with the PS raw filter got rid of the remaining red pixels, though perhaps it's now too dark a background...

That looks great! 

Not the easiest of data to work with for sure

[Felias]

8 hours ago, Iem1 said:

That looks great! 

Not the easiest of data to work with for sure

Thanks. I'm used to this kind of noise, since I also have a Canon and can't normally spend more than three or four hours in the fields, so my SNR is pretty low. I deal with a dirty background and horizontal bands quite often! I've been thinking of buying a CMOS for the summer...