The Helix Halo

[matlud]

Hi everyone,

Located 655 lightyears away in Aquarius is the famous Helix nebula. The Helix nebula is one of the most extensively studied and imaged planetary nebula, and has a number of very interesting structures, including small central cometary knots, large-scale emission arcs, and a bipolar outflow causing bow-shaped filaments and shocks.

When planning this project, I came across a paper by Zhang et al discussing a possible halo around the Helix nebula. On Galex UV images, they detected a very faint possible NE jet, a SW bow shaped filament and a diffuse Southern Halo. I decided to take a deep image of the Helix to see if I could detect these infrequently seen features in Ha emission. I had also noticed on some images, faint OIII emission occurring around the NE and SW arc’s and wanted to see if I could clearly define this OIII emission.

https://www.iceinspace.com.au/forum/attachment.php?attachmentid=311177&stc=1&d=1696731123
Helix Halo features in IR and NIV from Zhang et al, The Astrophysical Journal

Data was captured with my Nikon 400mm f/2.8 including all of the nebulosity data seen here, but I did add some of the brighter stars from some data I had from my APM LZOS refractor. I used drizzle integration, and the outer faint halo was processed using continuum subtraction and carefully masked to not blow out the brighter inner ring.

https://www.iceinspace.com.au/forum/attachment.php?attachmentid=311176&stc=1&d=1696731123
Astrobin: https://www.astrobin.com/h8hnt0/0/

Cheers,
Mat

Technical
Nikkor AF-S 400mm f/2.8E FL ED VR
ZWO ASI6200MM Pro
10Micron GM1000 HPS
Chroma Filters
Location: Dunedin NZ
Integration: 84h 30′

[joshman]

That's is a phenomenal image, and an amazing comparison with the Scientific image. Not to mention the amazing processing you've accomplished. I've just done some rudimentary math, and I would need to capture nearly 650 hours with my setup to have the equivalent SNR.


An incredible result all round!

[TrevorW]

Yep a lot of good data makes for a great image :)

[strongmanmike]

Beautiful result Mat, another worthwhile project, nicely delineated Ha and OIII details too :thumbsup: Maaaybe some colour in the stars might look good.. :confuse3:?..meah, just a suggestion, you have probably already tried :)

Like the Dumbbell nebula (https://www.astrobin.com/full/m1g53a/0/) in Vulpecular, it's amazing how many images are going super deep on the Helix these days too :eyepop:, not so long ago, if you picked up the main "eyebrow" well, you were bloomin well cheerin! :lol:

Well done indeed :drink: :thumbsup:

Question, was that done with the lens wide open at F2.8?

Mike

[matlud]

Thanks Josh! The Nikon is fairly unique in having a decent aperture for the focal length (in refractor terms at least) so it does help to hoover up the photons :)

[matlud]

Thanks Trevor!

[matlud]

Many thanks Mike! That’s a good suggestion, I’ll have another look and see if I can boost the star saturation :thumbsup:

I use a small 3D printed aperture mask on the lens so it is operating at f/3, which I found tightened the stars a little and with the 5nm filters I wasn’t really losing any significant speed :)

CS, Mat

[Dave882]

Wow that’s stunning. The depth and subtle detail is just magnificent. Interesting write-up too thanks for sharing!!

[gregbradley]

A magnificent Helix Mathew.
Gee that Nikon lens is good but also very pricey- one I saw on ebay was AUD$6,600 or so.

Greg

[Peter Ward]

I really like the depth and in particular, colour of this image.

Though I'd also have to observe the overall resolution is a little soft....
e.g. the faint shock-front arcs you've done well to capture have
subtly blurred edges rather than the hard delineation larger instruments typically render.

That said, this is still a benchmark result many would struggle to emulate.

Nice one :thumbsup:

[matlud]

Thanks David, much appreciated.

[matlud]

Thanks Greg! It’s not an inexpensive lens for sure but considering it’s a 143mm fluorite apo with a built in reducer it’s used price compares well to the current prices of FSQ106 with reducer (if you can even get one!) or other faster refractors. Of course you have to deal with external lens focusing and the lens mount but there are some good solutions for this. Cheers, Mat

[strongmanmike]

Ah yes, this sounds familiar, I think I may have asked the same question previously :question:..oops forgot :screwy:

I'd love one :)... but at around $7K huh?...that ain't happening anytime soon, I'd need a new camera too with small pixels and a decent real estate size :doh: :sadeyes:

Look forward to seeing more :thumbsup:

Mike

[matlud]

Thanks Peter, appreciate the feedback. I think the outer arc softness you notice comes somewhat from being undersampled at 1.97”/pixel, the smaller aperture compared to the big guns, but mostly the noise reduction given how extremely faint the outer arcs are. Overall I was very happy with the detail the lens captured given the sampling/focal length and the drizzle integration really helped with the under sampling.

I have pondered getting something around 12” aperture in the future to see what I can get from my skies for smaller objects, but there seems to be slim pickings these days for higher end optics around the 12” range, other than planewave CDKs :question:

CS, Mat

[Peter Ward]

I can see your dilemma, a quest for resolution also usually involves the added cost of quality gear, and in a 12" aperture this has gone through the roof of late....I'd also concur that a Planewave CDK would be hard to go past in terms of bang for buck in that category.

[Kuz]

Well done Matt, as Peter mentioned bench mark image

[Addos]

Thats a quality capture there Matt, great definition in the often missed fainter regions surrounding. I hope you keep adding to this dataset in future years! :)

[Paul Haese]

Good depth in the image Matthew. The outer shells are well seen and processed.

[Eis]

This is inspiring. How do you look for papers?

[JA]

Well done Mat, that's a wonderful image :thumbsup::thumbsup:

... especially when one considers (I had to check it out:D) that it's an ~20% crop of what the full-frame sensor saw through the 400mm focal length lens. Amazing.

Best
JA

[markas]

Spectacular! As has already been said, it's a benchmark image.
Mark