First ever Galaxy - A Widefield M51

[Jarvo]

Evening

This is my first attempt at getting a Galaxy (normally i prefer the planets but things are getting a little sparse now). M51 is one of my favourites.

So I hooked up my little refractor (70mm Travelscope) onto the EQ5 and started taking some shots. I'm quite pleased with the initial results - I got some spiral structure in there including the arm connecting two galaxies.

I got 22 subs of 1 minute each at ISO 800 plus 4 dark frames before the clouds rolled over.

Processed the results in Deep sky stacker....and this is where I came unstuck.

i've been messing about in Photoshop for the best part of the afternoon and this evening and have only manged to adjust the Autolevels with a little success.

Is there any way of getting rid of the orange glow? Tried Levels, Curves and Brightness / Contrast adjustments without much success. i'll keep at it tomorrow (proving to be a good learing curve ) .

Comments and advice would be appreciated.

Cheers

Jarvo

[Ant]

Had a bit of a play...

It's not ideal to get rid of LP in processing - it's best to filter it out to start with if possible...

But here is quick method of doing it.

1. Open image in PS and duplicate the layer (you have Background and Background Copy).

2. In the layer box select difference from the drop down list.

3. Click on the Background Copy (in the layer box) and then from the menu's at the top select Gaussian Blur from the Filter ==> Blur

I usually play around with the slider and end up with quite a high number - but for your image 95 worked quite well.

Then I flatten the image and process further.

Here is what I managed very quickly with your M51 Image!

Isn't it nice when you get your first DSO - M51 is a great target and IMO best imaged with a bit of space around it. Well done and I look forward to seeing more

Cheers

Ant

[Sparrow]

Well done Jarvo - good effort and M51 is defiantely there.

The orange glow will be light pollution. Deep sky stacker will correct it to a certain extent - if you stack it again, there is a setting to align the RGB (Red green blue) on the first tab of the settings - this may well substantially correct it.

You may also benefit from taking and using some "Flats" - these are short exposures of probably about 1/120 or thereabouts with your camera in the scope at the same orientation as it was for imaging. The aim of the flat is to remove uneven illumination such as tunnelling (vignetting) by taking pictures of an evenly illuminated surface. Theway I do mine is to point the scope at the bright sky and put a piece of A4 printer paper in front of the scope. These are then added in to Deep SKy Stacker as flats.

Hope this helps

Regards

John

[Demonperformer]

Jarvo, excellent first galaxy ... much better than mine was.

You may want to increase the number of darks you take. The optimal number seems to be about 20, as after this you tend to get reduced extra benefits for the extra darks, and below this you are not reducing the noise as much as can be achieved with relative ease. FWIW, to get the best match, I tend to do a batch of 10 before I start my lights, and a further batch of 10 after I finish, then put them all into DSS together. That is probably a bit extreme, but it works quite well for me.

HTH

[Jarvo]

Thanks for the excellent advice guys. Its really appreciated. i'll have a fiddle later today

Jarvo