Fireworks galaxy and NGC6939

[astrodam]

Hi all,

I'm still quite new to imaging and last night I attempted the fireworks galaxy and its neighbouring open cluster. The moon was pretty low when I started so I hope this didn't affect my exposures. I ended up with 11x45s lights and 5 darks (using the kit listed below) which I put through DSS and then tinkered with in GIMP2.

I just about teased out some galaxy detail but I was disappointed about the reddish glow in the middle of the image which I couldn't seem to remove without reducing the galaxy detail Does anyone have any hints about processing or could tell me what the glow is in the middle of the image is down to?

Thanks for looking Clear Skies!

[Cloudwatcher]

Had a quick lunchtime play in Photoshop......reducing the red area went OK I think but my attempt to enhance the Fireworks galaxy turned out to be a bit of a

damp squid.

[astrodam]

Thanks CW, I like that the red area has gone, what caused that? Is it the mirror of my scope? is this removal possible in GIMP2? And do you think its a case of needing a lot more data?

[dph1nm]

I like that the red area has gone, what caused that?

Almost certainly vignetting - all optical systems have it. You need to take flats to remove it.

NigelM

[Ibbo!]

I would say more data would help

Steve

[astrodam]

Almost certainly vignetting - all optical systems have it. You need to take flats to remove it.

NigelM

I have seen this phrase floating around, I shall look into how to take flats is there an easy way to do this?

[andrewluck]

Point the scope at a clear sky (could also use a laptop screen with an all white display.

Set the camera exposure on auto and take a whole sequence of images. These can be combined as a master flat.

Not very scientific but it worked for me when I was starting out with a 350D.

Andrew

[astrodam]

Point the scope at a clear sky (could also use a laptop screen with an all white display.

Set the camera exposure on auto and take a whole sequence of images. These can be combined as a master flat.

Not very scientific but it worked for me when I was starting out with a 350D.

Andrew

Thanks Andrew, Laptop screen sounds good My bathroom window overlooks the garden and when the light is on it is really bright, I was going to try pointing my scope at the window with the light on to take flats. I will try your idea out though, next time. Nice one