background?

[neil groves]

I went out to find M101 and failed AGAIN, so I turned my attention to M51 since my other target that evening was obliterated by the moon, I scanned around with a low power wide view eyepiece and after some time came across this little guy, I knew it wasn't M51 but since I had it in my sights I thought i'd image it anyway, I only managed just less that 30 mins before cloud spoilt my play time however I was excited to get it processed so I could find out what I had caught, it was a [removed word] to focus since there were no bright stars in the area to conveniently slew to so I had to take a few shots and guess my best focus, anyway after consulting my star atlas I found it was M94 based on the layout of the surrounding stars, this is the best I can get it so far with my meager processing skills.

lights = 57

darks  = 5

flats =  10

ISO 1600

SW ED120

Canon T3

My question on this and I guess all my other shots to date is how can I get my background darker and less noisy without losing detail in the object?

Neil.

[Zakalwe]

Shooting (RGB) with a full moon will always give more noise. The background sky will be bright and the camera will pick this up.

More integration time is what's needed to combat noise. That and longer sub exposures...57 lights in 30 minutes = 31 second exposures. Short exposures will be more affected by read-out noise as the signal hasn't had that much chance to drown it out.

You have a gradient in the image, which is to be expected when the moon is out. Gradient Xterminator can help with that.

http://www.rc-astro.com/resources/GradientXTerminator/

Finally, I think that you have created a pretty decent shot for only 30 minutes integration time. Well done and ever onwards and upwards!

[ollypenrice]

Good answer from Zakalwe. I measure the background sky using Photoshop's Eyedropper (colour sampler) tool. Personally I like it somewhere near to 23 in each channel. To get it there I run DBE in Pixinsight, though Gradient Xterminator will do a good job. Then I go into levels and trim back the black points in each channel to get it right. There is a bit more to it than that but this will get you moving.

I agree that it has come out well. Galaxies and moon do not mix!

Olly

[neil groves]

I re worked this and got some worthwhile improvements so I think it just boils down to my sub par processing, all part of the learning curve

Neil.