Helix faintest details (a couple dozen photons/hr) 72 hrs

[Placidus]

We suspect this really might be (warts and all) the world's deepest plausibly amateur Helix in H-alpha.

Full sized image here (https://photos.smugmug.com/Category/Planetary-Nebulae/i-8NCj6fP/0/c5ec63dc/O/Helix%20H-alpha%2068%20hrs%202x2%204%20hrs%20 1x1.jpg) (2.2MB)

A three-panel (highly overlapping) mosaic, with at least 24 hours exposure, 2x2 binned, at each pixel, with a 20" PlaneWave CDK. Most of the image has 72 hours of exposure.

We've roughly doubled the exposure since last time. The Western chevrons are much less noisy now, and much sharper. We've added a sliver of extra real estate at the far right, where there is now a new, somewhat wriggly radial smudge heading off toward four o'clock.

The faintest details that are clearly and unambiguously recognizable in this radial smudge (where the exposure is 24 hours), are about 16 ADU above their immediate environment, which translates to 24 photo-electrons (48 photons) per one hour sub. There are other more ambiguous features surrounding it, which are visible in the Galex image.

The bright centre is overlain with 4 hrs of unbinned H-alpha. The blending of the two images has produced some artificially darker regions at the interface, but this does not affect the faint outer details.

We think we'll put our pen down now.

Very best,
Mike and Trish

[codemonkey]

Well I was planning on having a crack at the Helix when I get my new scope up and running, but I don't think I'll bother now having seen this one!

More seriously, that's a very impressive effort there guys; certainly setting the benchmark.

To be picky, there's a series of slightly diagonal lines visible on the left of the frame, I'm not sure if these are the result of blending in that unbinned data, but the image would be improved if you were able to clean that up. Anyway, that's not meant to detract from what is probably the deepest helix I've seen and will likely see for along time. Great job guys!

[strongmanmike]

Sensor me if required but holy fooking crap :eyepop:, will ya look at that..the faint features revealed are so captivating...
La Stupenda.
:love:

Mike

[Placidus]

Thanks Lee. We're sure your take will be very different. The diagonal lines are in the 2x2 version, so not related to blending. They're going to be due to integer roundoff somewhere along the way. They'll take a lot of tracking down.



Thanks muchly, Mike. Thrilled that you like it too. It's nowhere near as 'pretty' as a less deep but more clean and contrasty version, yet those super-faint bits must be telling an interesting story about what's going on, if only we understood the language.

Best,
MnT

[Paul Haese]

Now this is cooking with gas. I can see two chevrons to the right near the very bottom right that I have never seen in any images of this object. In fact I think they are the first time this has been imaged. I think you should image it just for another 20 hours to confirm the outlines of this outburst. I could be wrong but I think you might have made a further discovery just there.

[troypiggo]

Bar raised again. Absolutely awesome. Certainly will be the reference image for everyone here for some time.

[Placidus]

Many thanks Paul! Those shock fronts at the bottom right do look plausibly similar to the much larger number of clear ones at top left, so hopefully they are real.



Cheers, Troy.

We tried adding our old OIII and SII data to the image, but it made a hideous mess, so best leave it monochrome.

Embarrassing kindergarten mathematical mistake now fixed. :screwy: The 16 ADU are per 1 hour frame, not per 24 hours total exposure. :D Luckily the probable extra shock fronts Paul saw at bottom right are there regardless! :rain:

[Atmos]

There are so many expletives to describe this!
So I am just going to throw in an :eyepop: :lol:

Seriously this is a benchmark image Mike & Trish, absolutely spectacular.


Sadly they don't tell a great deal. Depending on the overall dynamics they may represent either:
1) Slightly earlier pulse
2) Concussion shock wave
3) Just be plain boring fainter material haha

[Placidus]

Thanks hugely, Colin!




Told you it would be fascinating! :)

[Octane]

Absolutely insane! That is a tremendous image.

Excellent work, M&T. :)

H

[multiweb]

This is so cool Mike. Very smooth. These chevrons look even fainter than I imagined. Love the image scale. A real tour de force overall. Kudos to you. :bowdown:

[Stevec35]

Pretty amazing stuff M&T! Detail I've never seen before.

Steve

[Placidus]

Many thanks, Humayun. A nice simple galaxy shot should restore our sanity.




Thanks so much Marc. :hi: Your city lights image already shows some of that faint radial streak toward four o'clock.

[Peter Ward]

Simply put: this is the new gold standard.

Even the pro’s have not bettered this.

Kudos indeed!

[DJT]

Hells bells, that’s really rather good!

Lovely work, so much faint detail coming out and those bow shocks over to the right are stunning.

Well done again.

[billdan]

Pretty cool M&T, the deepest I've ever seen of the Helix and I've seen plenty across different web sites.

[Placidus]

Thanks Peter, we are greatly encouraged.



Many thanks Peter. We would not have thought to do the strip on the right if it weren't for gentle prodding from the group.



Cheers, Bill, that's kind.

Oh, while we think of it, there is some SII in there, but it is ridiculously faint and uninspiring. No more Helix for us, at least for a day or two.

Very best,
MnT

[gregbradley]

Fantastic work. Its always great to see new images that take the view further and further and break new ground.

A tremendous effort.

Greg.

[alpal]

Hi Mike and Trish,
great work - new territory!
I hope you'll present it for an APOD?

cheers
Allan

[Andy01]

+1 Above - You MUST submit this to APOD, it's groundbreaking scientifically & aesthetically pleasing too - Benchmark image, deserving of all acclaim!
:party2::rockband::party2:

[alpal]

It's the deepest Ha picture ever taken as far as I can see.

[Placidus]

Thanks muchly, Greg.










Thanks so much, Allan and Andy. Spurred on by your encouragement, we've just submitted it. It would definitely give today's APOD (a flow chart on how to identify heavenly objects, in which, if an astronaut is waving back at you, it is the ISS) a run for its money.

[rustigsmed]

Beautiful work as usual m and t nice to be breaking into new ground!!

[Lognic04]

:eyepop: HOLY MOLY! Amazing picture!!!!!! :eyepop:

[Ryderscope]

Sheesh! Mind blowing detail. Presents the object in an entirely different light (no pun intended).

[Jen]

:eyepop::eyepop:

[E_ri_k]

Far out, that's dedication! Looking good :thumbsup:

Erik

[SimmoW]

Sorry for the late mind explosion, we are away on a short holiday! Wot everyone else said +1 googolplexian!

[Placidus]

Thanks so much folks, your support counts. Much appreciated.

It's taken three attempts over several years to get here.

One thing: you can take a pretty good H-alpha Tarantula if the full moon is far enough away, but something like the current image is most easily done from a pretty dark site and totally clear sky within say 5 days of the new moon. Otherwise, random noise and gradients make it very difficult.

Another is that at our image scale (0.55 sec arc per pixel) and a 16803 chip at -30C, 2x2 binning is pretty much essential. In past years with unbinned data we saw nothing much. Perhaps a very low noise CMOS sensor would help.

Very best,
Mike and Trish

[Lognic04]

Hi M&T,
How would you recommend a CCD (with say, a kaf8300 chip) compared to
something like the ASI1600? The only reason i'd consider getting a CCD would be to bin, is binning worth having a noisier chip?

[cometcatcher]

Deep. Very deep. Deeper than deep. Deepest deep that deep can go. :D

[RickS]

Amazing, M&T :thumbsup:

[Placidus]

Don't know the answer to that, Logan, but probably not. Binning only produces a 2x improvement in signal to readout noise. The cooled CMOS chips can be quieter than that. If they made an affordable cooled CMOS chip that was at least 16 megapixels, and it came with a well documented library, we'd definitely want one. But for us, a 2x improvement gave us in 68 hrs the equivalent of 272 hrs unbinned.



Thanks Kevin!



Cheers, Rick. Glad you like it. :)

[Atmos]

Whether binning is worthwhile also depends upon the sensor architecture. Binning the ASI1600 on chip doesn’t help, it is identical to software binning (sod. On chip binning the KAF16803 sensor (and to a lesser extent the KAF-8300) gives a vast improvement over software binning. Some of the Sony chips bin the best like the ICX-694/814 giving close to the theoretical 4x improvement.

[multiweb]

Legend. :2thumbs:

[Retrograde]

Yes I think you might be right.

I don't have any suitable superlatives to appropriately convey my awe.
:eyepop::eyepop:

[Placidus]

:D :hi:



Thanks muchly Pete. That's kind.