Is this light pollution?

[cuivenion]

I've recently started taking quite widefield images and I think I'm getting much worse light pollution than I have in the past due to the direction I'm imaging in. Just wanted to check before I invest in a filter:

The 1st image is with flats, the 2nd without flats. The image was taken with a Canon 500D and a 135mm lens at F8. 15 x 240s dithered subs with 50 Bias. The 1st image has 50 flats. I'm guessing the answer is yes.

 

[LightBucket]

Yes Almost certainly LP

[cuivenion]

Looks like I'd better get a suitable filter then. Thanks for the reply.

[wxsatuser]

You can just subtract the LP.

Try Jerry's simple method here.
http://www.skyandtelescope.com/astronomy-resources/astrophotography-tips/remove-light-pollution-astro-images/

[cuivenion]

Thanks. I think I might have a look at photoshop. I tried pixinsight and found it hard work.

[Scooot]

2 hours ago, wxsatuser said:

You can just subtract the LP.

Try Jerry's simple method here.
http://www.skyandtelescope.com/astronomy-resources/astrophotography-tips/remove-light-pollution-astro-images/

Hi Mike, In your opinion do you think trying to subtract the light pollution is better than using a filter. I wonder whether I could expose for longer with a filter? 

[cuivenion]

Well after giving Pixinsight a second chance and concentrating a bit I managed this:

It's a ways off perfect and needs a lot more data, but I'm really happy with the improvement. Looks like I'm getting pixinsight for my 40th birthday!

[wxsatuser]

1 hour ago, Scooot said:

Hi Mike, In your opinion do you think trying to subtract the light pollution is better than using a filter. I wonder whether I could expose for longer with a filter? 

Knowing how to subtract can come in handy, a filter will help with longer exposures but will not stop gradients.

PixInsight DBE can deal with LP and gradients, subtraction, as well as flattening, removing vignetting by division.

[Dave In Vermont]

Though I don't know how to do such (yet), I've read that there's a way to also remove CA (Chromatic-Abberation) from images taken with an achromatic-refractor. Which would save a tremendous amount of money on needing to purchase an apochromatic-refractor - or a similar higher-priced telescope - to remove the effect of CA.

You can use one of several types of filters to reduce the CA in an achromatic-system. But these filters also have the effect of giving one a pronounced yellow colour to the view.

Oh - and that's a beautiful image! Please keep going!

 

Enjoy!

Dave

[cuivenion]

Thanks Dave!