Hunting Barnards Loop

[Whistlin Bob]

I’ve been fascinated by Barnards Loop ever since I first saw a photo of it- an emission nebula that covers a huge part of the sky. In case you’re not familiar, it’s a large loop of gas centred roughly on Messier 42 that encircles good chunk of the Orion constellation. It’s thought to be a remnant of a Supernova from a couple of million years ago at least 100 light years across. I had a go at imaging it last year, but wasn’t especially thrilled with the results, so definitely on the list for another go. Easier said than done when you’re fighting light pollution…
I started this on 16th initially with an IDAS light pollution filter and a Sigma 18-55 lens. Unfortunately the lens/filter combination produced some very strange effects, so I took the filter out and stacked 20 minutes worth of data from 40x 30 second shots. I’m to the North of my nearest town (Bortle 5 skies) and so Orion goes right over the light dome from the town- not a pretty sight:

I attacked it in Pixinsight with DBE. It’s a good tool, but the mess left behind from this one had me needing to clip the background out to get something presentable. Still- I thought it’d make a good base to mix some Ha over:

Next clear night was Christmas Eve. I waited for Orion to get nice and high in the sky and then had a go with a 7nm Baader Ha filter, collecting an hour of data. This really underlines how much LP gets generated by an average urban area. Despite around 95% of the visible spectrum being cut out, there’s still a pretty nasty gradient:

Did my best to sort it out, but it was still a pretty noisy image. Final result is below. If I want to get a decent version of this I think I’m going to need to go somewhere darker, but if anyone has any bright ideas for improving this in the meantime, I’m listening!