The importance of a dark sky.

[Phillyo]

Good evening one and all.

So I used to image quite a lot until about 3-4 years ago when I gave it all up due to other commitments, cloudy skies and...light pollution (LP) from a growing Lincoln City. However, I really miss it. I have 5 years left until I retire from the military and I'm considering using some of my pension to get back into imaging again.

I have toyed with the idea of trying to get the kit abroad and finding somewhere to host it but that has a lot of issues involved, so it got me to thinking. How important is light pollution, or a lack of it, for imaging? I understand that narrowband is affected less than LRGB, but lets assume I want to do a bit of both. Is LP just a game ender? Can you get around it with LP filters and/or more exposures to increase SNR?

Now, I live outside of lincoln in a village that has an SQM of 20.47 (for those that know that it is), so I'm not in the middle of a major city (London has an SQM of about 17.44, a true dark sky has an SQM of 22) so I know it could be a lot worse.

Thoughts/opinions? Do most people that image remotely do it more for the clear skies or is it a mixture of clear skies and LP?

Thank you.

Phil

[pete_l]

21 minutes ago, Phillyo said:

Do most people that image remotely do it more for the clear skies or is it a mixture of clear skies and LP?

Clear skies are more important than non-light polluted skies. With LP you can still do something but with clouds there are no options.

Having said that, a mid-20's SQM is pretty good so I'd reckon that you have a site that is eminently suitable for all types of imaging, not just narrow band.

[kirkster501]

Lack of clear skies in the UK is the biggest challenge.  I have so many half complete sets of data, missing a colour, that it ain't funny anymore...  When it IS clear, you can get most things in the can in UK suburban skies like yours and mine.

Oftentimes, even when it is "clear" by weather forecast standards, it is no good for astro imaging, with lots of wispy clouds passing through wrecking a lot of your exposures.  I count on about 20 - 25 nights per year that are any good for AP.  And some of those you have to do other things none astro of course too.

[dph1nm]

On 23/09/2019 at 19:47, Phillyo said:

Can you get around it with LP filters and/or more exposures to increase SNR?

Yes, but my advice is not to do the maths on how long it would take or you will just get depressed! Enjoy what you  have ...

NIgelM

[JTEC]

Apart from incidence of clear nights, potential relative freedom from light pollution and the possible advantage of a higher altitude site, there is the elevation in the sky of imaging targets to consider. By heading south from the UK, popular southerly targets like, say, M20 and M8 are higher in the sky which means less air mass and UK grime to image through. Add to that that some of the more southerly objects that are inaccessible from the UK become available.