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The Witches Head gazing up at Rigel

Martin-Devon

By Martin-Devon
in Imaging - Deep Sky

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Martin-Devon

Martin-Devon

Posted
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I started this on New Year's day and it's taken me 6 weeks to get enough data to assemble this image. It's a 4 panel mosaic, all in luminence with 32x10 mins subs in total across the left side and 18x10 min subs in total across the right side. Finding and framing this target is certainly not easy, it's very faint so you see virtually nothing with a single 10 min sub.

Rigel is up there in the top right hand corner and glows massively bright. This makes for very strong gradients and challenges with the processing. I tried to get some RGB but this was usually when there was some moonlight around, and with Rigel blazing away on top, the data was too washed out and just wasn't good enough to use. I also had a look for H-alpha, there is a faint signal and I know from others that it may add to the image - however it's driven me nuts getting to this stage, so for the moment at least I'm happy to settle for just the luminence data.

One "interesting" aspect that came up early on with the imaging - there were masses of geosatellite trails criss-crossing continuously right across the Head region. I've checked with Peter Shah (he posted a lovely version of this image a while ago) and he confirms this area of the sky is packed with them, so it's like the M1 motorway for geosatellites up there; I lost many subs due to this though.....

Ideally as ever, it needs more data, but with the UK skies the last 2 months that's been just impossible. So although it's far from perfect, it at least shows the potential of this target - I just love the way that the Witches Head looks up at Rigel, it's a classic composition. I've given it a slight "blue rinse" with a photo filter to give a 'ghostly' edge to the Witches Head, but it's a bit like marmite, you'll either like it or hate it!

I appreciate you looking though - Martin

8507159742_98e8e54db8_c.jpg

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Tom OD

Tom OD

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Great pic Martin. You're right about it being the highway for satellites. every plane in the sky seems to pass through this area too. i like the control you have on Rigel, it makes processing of this region very difficult. My only criticism is that there seems to be extra dust on the LHS, above the bright star which is sometomes called her ear-ring. Was there a gradient there?

Tom

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Gina

Gina

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WOW!! That's magnificent Martin :) I couldn't make out the Witch's Head at first but with scrolling up and down it just popped out at me :D Looks like she's got a mouse in her hair :D

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GlassWalker

GlassWalker

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One "interesting" aspect that came up early on with the imaging - there were masses of geosatellite trails criss-crossing continuously right across the Head region. I've checked with Peter Shah (he posted a lovely version of this image a while ago) and he confirms this area of the sky is packed with them, so it's like the M1 motorway for geosatellites up there; I lost many subs due to this though.....

What stacking do you use? Selective rejection in many stacking software can handle this, assuming you have a decent number of subs overall.

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peter shah

peter shah

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  • Very nice shot, a very difficult subject from the UK as it doesn't really get high enough out of the murky atmosphere and those sat trails are a massive pain in the rear.......I remember mine being a major challenge, I keep putting off going back to it ;-)
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Martin-Devon

Martin-Devon

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Firstly let me thank all the folks that have kindly looked & commented on my image - it's much appreciated!

There were a few specific queries and I'll try to address these now:

Mark72: you asked if I had a bigger version, sorry but I just use the free Flickr account and already I post on SGL at nearly the maximum size that this will allow. In due course I may open up an account with Astrobin or similar to make larger versions available

Tom OD: you asked about a specifc area, called the "ear-ring", it's best that I PM you on this so I can be clear exactly the area you refer to

Glasswalker: you asked about "selective rejection" methods during the stacking stage - I do my combining in Maxim using Sigma Clip mode, if you know of a better method though that may reduce losing subs with satellite trails going randomly through I'd be eager to hear

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