Tips on imaging NGC1909 Witch Head Nebula needed

[Davey-T]

Having at last assembled a suitable imaging rig ( QSI683 WO Star71) I'm waiting for the Moon to go away to have a go at imaging the Witch Head  Nebula for the first time, hopefully just a two frame mosaic.

As this is obviously not your "usual" HA nebula I'm looking for advice on the best way to capture it, have full set of filters so can try anything.

Dave

[Martin-Devon]

Yes this is one of my favourite targets for imaging. I did this target a few years ago, and there are several challenges (a) it's a broadband target, and nearby Rigel dominates the subs so very easy to get pronounced gradients, you need to decide upfront whether you want to include or exclude Rigel in your framing, ( there are an amazing number of pesky satellites tracking through this region, criss-crossing the Witches Head so make sure you use a good sigma clip routine in your stacking software to eliminate these, © the luminosity for the Witches Head is very weak, so try to get lots of data and you'll need to do this under moon-less conditions, (d) maybe concentrate on luminence data first since you can get a very respectable image just with this, if time and conditions allow, add RGB later to get star colour into the image.

Good luck,

Martin 

[Davey-T]

Thanks Martin, I realise it's not an easy thing to image having had a stab at it in the past with a smaller CCD, I was never going to get enough data for a full mosaic.

One plus point is now the street lights go off after midnight I should be able to get better Luminance subs than before, hopefully it won't be another of those projects that take years like my NGC7000 / Pelican mosaic 

Dave

[ollypenrice]

Martin has said everything that I would have said. It was on this project that I discovered the enormous improvement in the Sigma Clip that was made between AstroArt 4 and AstroArt 5. AA4 did not clip the abundant satellites but in 5 they vanished jusslikethat. On Rigel, Tom was afflicted by flares when it was out of shot. That was with his FSQ106N. I had the same thing using the Baby Q and reducer but, when I tried without the reducer, I was OK. So some setups will struggle with Rigel and some won't.

There is, in fact, Ha signal which will give considerable added interest to the background though the nebula is reflection. (I must shoot some Ha for meine this year.)

Olly

[Davey-T]

Took a single 1200 sec Luminance sub last night in very windy conditions so rubbish tracking and a convoy of satellites but got a recognisable head so looks promising if only we get a few good nights  

Dave

[Uranium235]

Best tip to start the Witch head, make sure you have the right sky conditions to start. Its quite low, so it wont like any murk or LP - I tried it a few years ago but barely tickled it.

Another thing you might want to try is that its quite a "blue(ish)" nebula - so it might be worth adding a percentage (perhaps half) of the Blue channel subs to your Lum stack to improve the signal further.