H-alpha Heavy Horsehead

[Ikonnikov]

I've been trying to make a reasonable-sized Horsehead image with my C8 hyperstar since early December with the ultimate aim of making a print but this is becoming a bit of an ordeal! I managed to collect a few hours of Ha data over the Christmas period and although the seeing was relatively poor I got some reasonable detail out with deconvolution, HDR transform etc and decided in Jan/Feb to try and get some RGB to complement it.

However what I hadn't counted on was quite how bad the internal reflections of Alnitak were going to be; attempts in the past with my old OSC camera seemed fine but mono plus RGB filters (both with and without an LPS P2 in front) gave multiple reflections brighter than most of the nebulae! Even placing the star in the centre of the field gave off centre reflections so I tried to devise a mosaic strategy to avoid them. Of course this meant taking multiple fields for each channel just to match the single field of Ha data, greatly increasing the time required and of course the weather has been a total pain to boot.

Long and short is I haven't managed to get a high quality RGB signal for the whole frame yet (and time is running out as Orion disappears for spring/summer) so I've given in and just made an HaRGB image with what I've got, hence it's severely cropped (to remove reflections) and rather H-a heavy. I'm encouraged by what it shows so far but lord knows how long before I 'finish' it! If the weather is kind I might try using my newish Canon EF200 L F2.8 lens to grab some more RGB (the resolution with my Atik 490EX @1x1 is pretty similar to the hyperstar @2x2 and hopefully reflections will be much less and if present easier to deal with, with the much bigger field of view. Of course that would require me to get the lens to CCD chip spacing bang on which isn't proving as straightforward as I'd hoped....

Paul

Full res image:

http://cdn.astrobin.com/images/thumbs/3ba70d60dc254f0b49b0870de49a951d.1824x0_q100_watermark_watermark_opacity-10_watermark_position-6_watermark_text-Copyright%20Paul%20Cordell.png

[Brent]

Beautiful! I actually love the unusual cropping of this even though it was born out of necessity

If you fancy posting the uncropped version, I for one, would be interested in seeing it, reflections and all?

[Ikonnikov]

Thanks! For this section of the image I cropped the reflections out pretty early on so it would be a pain to re-process from scratch (and I'm not even sure I could get it quite the same a second time!), however I will post the full sized image in a bit; it doesn't have major reflections but has weaker colour than the smaller image so looks a bit drab in comparison.

[Brent]

I wondered if that might be the case soon after I posted, please do post the full sized though.

I was hoping to get a chance to have a good attempt at the Horsehead this year. Unfortunately, it soon disappears behind the house and on the last two times I've set up, the weather has scuppered me. I'll get it next season though!

[Tiny Small]

That is lovely. I think the unconventional framing works well here.

[Ikonnikov]

Ok here's the larger field; with the lower RGB signal I haven't been able to make the dust and the colour/detail in the flame as pronounced.

Full res image

http://www.astrobin.com/160918/

[Ewan]

That's still a fantastic image regardless of any reflections, very nice.

[Brent]

Yes, very nice. Looks good to me.

[jonnopfc]

Personally i think its cracking just the way it is. Almost a plasma ball type look to Alnitak which i suppose technically you could say it is.

[Dave Smith]

Fantastic image, lovely colours.

Dave

[Fay]

I like your first image with its detail, very nice indeed!

Fay

[Ikonnikov]

Thanks all for the positive comments, looks like this is likely to be the last version for this season unless I'm lucky with the weather around the next new moon. But it's great that you can keep coming back year after year to add to and improve your images (albeit with an exponentially increasing number of exposures required!).

Paul

[bluedandelion]

Beautiul image.

Ajay

[ollypenrice]

I don't think I've ever seen Flame detail in so close to Alnitak before. Well done.

Doing this in the 14 inch ODK, Yves and I had a murderous time with reflections as well, the worst not being from Alnitak but from the small group of blue stars above the Horse. We had to crop about half the image to get a presentable horsey.

The scope which shrugged off Alnitak et al better than all the rest was the TEC140 which simply controlled the lot to perfection. It doesn't always thrive on blue stars but this time it made light work of the problems.

Olly

[Ikonnikov]

Thank you, it’s a little noisy/overstretched for my liking but I’ve not been able to get enough subs to show the fainter detail cleanly yet. Maybe adding some L-subs to the mix will help if I get the chance.

It’s somewhat reassuring to hear that even high-end reflectors are susceptible to these pesky reflections; I presume a refractor is the only trouble-free way to go to avoid them?

Paul