2hrs of M8 & M20

[AstroJason (Jason)]

Hey guys,

After some advice here I tried the M8 region again but this time 240 x 30 second exposures. I tried adding flats in this time as well, however I found that when I began to stretch the image a rainbow gradient appeared. Even after I applied my gradient removal process. So I restacked the data in DSS and the rainbow was gone... I used the blue dusk sky for the flats... maybe this was the reason for the rainbow cast?

Anyway I was able to push this data further than my previous attempt which was just 1 hours worth of data. Thinking about combining both sets of data to get a 3 hour image but will save that for a rainy day...

Higher quality image available here; http://www.flickr.com/photos/5900499...0031/lightbox/

Again, any feedback is greatly appreciated.

Cheers,

Jason

[nebulosity. (Jo)]

G'day Jason

I did a bit of a mosaic around M8 and as soon as I started streaching the images I got Red/Green/Purple coloured bands across them, sounding similar to yours, I am not sure what it is or were its coming from, hope someone can tell us.

I would be interested to know exactly how you removed it?

Thanks
Jo

[AstroJason (Jason)]

Hey Jo, I found that the flats I was using were the cause of this rainbow gradient appearing when the data was stretched. My flats were of the dusk sky, so were blue, not sure if the colour of the flats had anything to do with it. Anyway, I simply restacked the image in DSS again but this time without the flats and the rainbow appearance was gone.

I follow the gradient removal process that Doug German goes through here; http://www.youtube.com/watch?v=yTEVMH_WE80 its very simple and works fantastic. Hope that helps you.