Helix faint features: One photon per pixel every four hours

[Placidus]

Trying to get the absolutely faintest outer shock fronts in the Helix, we stacked 16 hours in one-hour 2x2 binned subs, taken over this last new moon.

The faint thin shock fronts coming to a point at the extreme left of the photo were about 6 counts above background in the stacked image. That's about 9 photo-electrons. At 50% photon efficiency, that means that about 18 photons hit each relevant 2x2 binned pixel over 16 hours. That's about one photon per unbinned pixel (0.55 sec arc) every four hours! The brightest nebular features of the "eye" are about 360 times brighter.

We've previously tried this using 30 hours of unbinned subs, or 10 hours of 30 minute 2x2 binned subs, and gotten nowhere near the same result. Nothing to show.

The image is 30% full size, but these features are so faint that looking at them full size doesn't tell you much more. Wavelet noise reduction, but no deconvolution.

Aspen CG16M, PlaneWave 20" CDK. Field 36'arc, north up.

Best,
Mike n Trish

[AstroJason]

Wow, that is incredible. Love the bow shock looking features in the faintest parts of the image.

[Placidus]

Thanks, Jason!

[pluto]

That's great to see, well done!

Is this Ha or L?

[Peter Ward]

Very impressive result :thumbsup:

...only goes to prove aperture rules :)

[RickS]

You've pulled out a lot of faint detail that I didn't get in 20+ hours of Ha (30 minute unbinned) with a mere 12" scope. Nicely done!

[Placidus]

Thanks, Hugh. H-alpha via 3nM Astrodon filter.

[johnnyt123]

That is amazing....
Hubble would most certainly show respect......

What focal length/f-ration did you take that at ??
all native to the scope?

John

[multiweb]

That's insanely deep. :thumbsup::thumbsup: :thumbsup:
Never seen those v-shaped fronts at 10 o'clock. Looks like wake patterns.

[Placidus]

Thanks so much Peter. I think we're starting to see that the strength of the 20" under fairly ordinary Central Western NSW seeing (altitude 666m) mostly round 2 to 2.5 sec arc is faint stuff, not sharp stuff, and that binning and long subs are our friends.

[Rac]

Excellent! I'm trying to get a good amount of data on this myself. Those outer shells ARE very faint!

[Octane]

Unbelievable. :D

Are you going to add colour? Might have to wait several years. :)

H

[Placidus]

Thanks muchly, Rick, Marc, Raymond !!



Thanks John. Native focal length, 3454 mm, giving F/6.8.

[Amaranthus]

Excellent! Just needs a bit of HDR tweaking to bring out the core and it would look incredibly awesome.

[Placidus]

Cheers! We have 9x30 2x2 + 8x30 unbinned OIII, but I think we'll just have to start again with longer deeper subs. Sadly, the guide camera A/D offset is playing up and summer is a-coming in.

[marc4darkskies]

Deepest Helix I've seen! Excellent Mike!

[rustigsmed]

wow- that is great - so much going on in the faint stuff!
would be interested to see the difference you had with the 10 hrs of 30 min 2x2 for comparison.

regards,

rusty

[SimmoW]

Insane depth and detail, even more insane FL! Well done

[Alchemy]

Impressive work, very rarely do you see this feature, except in large professional images

[rmuhlack]

Now there's something to aspire to. Incredible image. :thumbsup:

[strongmanmike]

Awesome Mike and Trish.. reeeally amazing depth and resolution.

Only other image I have seen of the Helix that goes as deep and shows those intricate fine shock fronts as well is one by the Galaxy Evolution Explorer (GALEX) (http://minsex.blogspot.com.au/2012/05/ngc-7293-helix-nebula-in-ultraviolet.html) Interesting that the Ha features match the UV ones so well.

Man, I wish you had a slightly larger FOV...?..mozaic perhaps :question: :D

Great scope and mount and observatory you have :thumbsup:

Mike

[Bassnut]

That's just nuts, insane depth right there :eyepop:. Goes to show what 1 hr subs on serious appature can do. And bin 2 too, excellent :2thumbs:

[Placidus]

Marcus, Russell, Simon, Clive, Richard,

Thanks for the encouragement.

Best,
Mike n Trish

[Placidus]

Hi, Mike,
That Galex shot is just jaw-dropping. Thanks for the link.

Best,
Mike n Trish

[Placidus]

Cheers, Fred. Vaguely wonder whether to try even longer 2x2 subs one day. Unbinned, there's no great advantage, but 2x2 I'm not sure of the maths.

[Geoff45]

Gobsmacking Mike!

[alpal]

Hi Mike,
What an amazing photo.
I am sure it has scientific value.

cheers
Allan

[Rod771]

Incredible!! Thanks for sharing. :thumbsup::thumbsup::thumbsup:

[DJT]

That's an awesome Image, Mike and Trish. Incredible detail. Top Job!

[LewisM]

GULP!!!!!

Wow indeed

[Placidus]

Cheers, Rod, Allan, Geoff, David, Xeno in Lux Urbis,

Thanks muchly. Glad you like it.

[gregbradley]

That really picked up some fine detail. Nice and deep. The main feature here I think are those fine shock fronts you mentioned. I haven't seen them before.

Greg.

[Paul Haese]

The binning would account for why I was struggling to get much with the 12" with 30 minute subs at 1x1. This has got me thinking now. Binning will reduce resolution a lot on the 12, so I am wonder how long I would need to go to capture the same amount of photons. I think over 1 hour per sub.

Excellent detail. Inspiring image.

[dvj]

Nice explanation and image. I tried 50 hours with the FSQ and 16803 unbinned and did not get any of the faint structures seen above the main "v" structure to the left. Well done.

j

[sheeny]

Wow!

:bowdown:

Al.

[Placidus]

Hi, Paul,
Thanks muchly! With 0.55 sec arc pixels and very best 2 sec arc seeing, we're not quite critically sampled 2x2, so we're elsewhere messing around combining 1x1 for stars and highlights, 2x2 for faint nebulosity, and pro rata in between. The technique fails miserably with small faint background galaxies, but seems good for extended stuff. Will have something to show soon.

That said, your shots are hugely sharper than ours!

Best,
Mike

[Joshua Bunn]

Inspirational Mike and Trish! Fantastic effort with the results to show.

[Mighty_oz]

Fantastic picture :) You should get an APOD for this !

[Paul Haese]

Yes my seeing contributes to that sharpness. Often quite good. I might have to try 2x2 binning on the helix as a test myself to get that faint stuff out.

[Placidus]

John, Al, Joshua, Marcus,
Thanks very much indeed.
Cheers,
Mike n Trish

[Placidus]

Thanks Greg! I was rather glad when Strong Mike showed me the Galex image and it had the same features. Hadn't just made them up. If I were to start again, I'd frame it very slightly to the left and very slightly higher.

[seeker372011]

Inspected mind. Confirmed it's boggled.

[Nico13]

Special, very very special.

[Placidus]

Hi, Narayan, Hi, Ken,
Thanks indeed.
Mike

[Ross G]

An amazing photo Mike.

Incredible detail!

So special when your image moves from "just a photograph" to science.

Ross.

[Shiraz]

What a wonderful result - exceptional depth and detail.