Falls of Orion

[Peter Ward]

I have previously uploaded parts of this image, I've decided it's high time to stop tinkering with the data and reveal the full field.

While M42 is the perennial favourite, particularly for wide field imagers, it's not often revealed with truly high resolution, which I hope I've broken some new ground on here.

Personally it's one of the best images I've done in a while....

The link is here (http://www.atscope.com.au/BRO/gallery450.html)

[Retrograde]

Wow - fabulous detail and contrast!

[Nikolas]

That is an amazing picture, What instruments did you use?


Edit: Found it on your picture page

[Imme]

Magnificent Peter, truly a sight to behold that one. Best I've seen.

One of the best IIS has had posted this year I'd say

You should be patting yourself on the back with that one.

[DavidU]

:eyepop: x2

[Stevec35]

Ho hum - another M 42. A seriously good one though!!

Cheers

Steve

[Peter Ward]

Thanks Steve :lol: Indeed not *another* M42.....but I'm happy enough not to re-visit M42 for quite some time after this one .


Ta.



:thanx: I think I finally got then colours dead-nuts on.....with sooo many variations on the net I used the AAO image as the standard to follow.


Thanks. I could have used my FSQ, but think the Alluna gives a more interesting view.



Ta. The full 4k .tif data actually hints at some of the dark globs seem in the Hubble M42 image (which still makes my data look like it was done with crayons :lol: )
but I'm stuff pretty chuffed to see I'd caught many details in the ESO/Hubble data.

[spiezzy]

:eyepop::eyepop::eyepop::eyepop::ey epop::eyepop::eyepop::eyepop::eyepo p::eyepop::eyepop::eyepop::eyepop:: eyepop::eyepop::eyepop::eyepop::eye pop::eyepop::eyepop::eyepop::eyepop ::eyepop::eyepop::eyepop::eyepop::e yepop::eyepop::eyepop::eyepop::eyep op::eyepop::eyepop::eyepop::eyepop: :eyepop:

[Wussell]

Fantastic :)

[alpal]

Hi Peter,
I don't think I've seen a better M42.


cheers
Allan

[Peter Ward]

:thanx:
I know my forthright nature likely precludes any fanbase/clique following...
So your entertaining and very positive feedback is very much appreciated !

Guess it's a keeper then :)

[leon]

Keeper, you say I should think so that is just brilliant, and as said already I too have never seen so much detail in a M42 capture, beautiful image Peter.

Leon

[Peter Ward]

Thanks very much Leon. Glad you enjoyed the view.

[multiweb]

Very smooth Peter, love the colours and details. :thumbsup:

[Atmos]

This is very reminiscent of an image Rolf posted a while back, albeit wider and with an edge on contrast so very well done :thumbsup: :)
My only gripe is that there are too many damn stars around the Trap to figure out which his which :lol:

[Benjamin]

Nothing to say. Astonishingly 3D :jawdrop:

[Peter Ward]

Many thanks



:lol: While the web version I've uploaded doesn't really show the fine details in the 4k original...I'm happy to be mentioned in the same sentence as Rolf, who's work is simply awesome IMHO.



Ta Marc. I guess the details come down to the fact the Alluna can deliver 5 micron spot sizes (but only in orbit :))
however imaging pretty much at sea level, I'm never going to see that. (the mind boggles how this puppy would perform in a high Chilean desert)
Even so, on sub 2 arc sec seeing nights the data
doesn't need any fancy processing, it pretty much just needs calibration and scaling
which I guess is the really remarkable bit.

[topheart]

WOW!

Such great dynamic range, contrast and detail!
Cheers,
Tim

[Andy01]

Very smooth & colourful Peter. :thumbsup:

Something not quite right with the core though, looks a bit flat & a tad muddy, like it's been burnt in too much?

Lovely image regardless :)

[Peter Ward]

Ta Andy..yep...I'll take that on board...a little more sparkle in the core added just now. :thumbsup:



Thanks Tim.

[DavidU]

Just had to have another look at this beauty.The core is awesome.

[Chapstick]

I can't add anything that has no already been said - this is one of the best imagine I've seen period, breathtaking.

[Peter Ward]

Thanks gentlemen...much appreciated.

[Slawomir]

This is really a different image of the Orion. Fantastic resolution Peter. Your image shows very nicely that even the most popular targets are beautiful, mystical and breathtaking and definitely never ever boring. If a DSO image is boring, the reasons are somewhere else, but the DSO itself is never to blame.

[Peter Ward]

Ta...and very kind of you. I'll go with those sentiments about DSO's.

Sometimes you need to get up super-close to make the ordinary extraordinary.....which is why I suspect the Hubble imagery is so awesome...

I'd also comment imaging at +3000 mm focal length is hard....so much conspires to ruin your efforts, but I'd invite all astro imagers to move away from the cosy sub 1000mm zone and push the envelope...you may be surprised at the results :thumbsup:

[FlashDrive]

Blimey, that's GORGEOUS :eyepop:

[Peter Ward]

Thank you Col.

I'm lucky to be able to push the envelope occasionally. :D

[Slawomir]

I’m sure imaging at such long focal length is not an easy task. I’m also sure that nearly every amateur would love to move away for cosy shortish focal lengths, but unfortunately quality DSO imaging at 3000mm+ requires an investment in excess of $50k, which for most is a bit too much to take sharper but still just pretty images.

Thank you for the invite nonetheless :)

[Peter Ward]

I take your point, but there are some excellent focal extenders on the market that get you there and don't require anything like a $50k budget. Most larger SCT's, while optically a little slow ( not a biggie with linear response CCD's, just expose for longer) are also a great workhorse. I used a C11 for many years.. the key to success is a rigid and accurate mount IMHO....but that's a topic for another conversation.

[Slawomir]

Thank you Peter - sounds like an interesting idea as I have been looking at options for a second scope for higher resolution imaging.

[keller60]

An amazing Messier 42! So many fine details.
Thanks for sharing!

[Derek Klepp]

Peter a truly spectacular image .I do hope you print this and hang it up somewhere.
Derek

[gregbradley]

I agree a spectacular M42. Makes me want to image it again.

Greg.

[codemonkey]

Great result, Peter.



I'd personally argue that focal length is only part of the picture and it's the image scale that counts. For example, my piddly little 8" F4.5 works out to a mere 989mm when combined with the Paracorr... but that's still 0.5"/px with my 2.4 micron pixels. I believe a 16" Alluna combined with the 16803 works out to 0.56"/px while being in excess of 3m.

[Peter Ward]

Many thanks. You know, I've long struggled with this and wondered why I get better resolution with when the numbers should pan out in a similar manner.

I suspect it is purely how the seeing affects the image at the focal plane. With a large aperture, the image is stable, but suffers from a high frequency, localised "ripple". Smaller apertures have less "ripple" but are also less stable. Both smear the image..but I have no idea how to determine what is the best FL+sampling rate for conditions on the night.

But another aspect is, at the same sampling rate, I get 4x the flux with a 16 than I would do with an 8 inch aperture. Signal certainly helps!

I have tried smaller, decidedly faster optics, but all they seem to give me is a wider field...which can be great....but the details are lost for reasons I frankly don't fully understand, given the seeing ultimately is the limiting factor. :shrug:

I'd be very happy to receive some insight here...any takers?


Yes! You have some amazing gear (and a dark site..you bugger! :) ) Image as much as you can, as tomorrow is not promised.



Thanks Derek, a good idea...if only we had more wall space :sadeyes:



Thanks and my pleasure.

[Logieberra]

Best I’ve seen. Thanks Peter!

[Slawomir]

In my limited understanding, this image (http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/Raylei.html#c1) says it all.

Small aperture quality optics is almost always diffraction limited (right) no matter how good the seeing is. A larger aperture is affected by a mixture of seeing and diffraction effects (middle), while largest apertures confidently resolve fine structures being always affected by the seeing only (left), and diffraction becomes negligible for our purposes. Even with seeing blurring the detail, DSO information is still of higher resolution.

I do understand this is a simplified approach but makes sense to me why large aperture resolves finer detail.

Image credit: R Nave, 2019

[Paul Haese]

Incredible image Peter. The detail is certainly extreme. Almost like you have an airless vacuum around your scope. I think though I have noticed a shift in your processing over the last few years. Are you using a sharpening technique which is different? It looks remarkably similar to the one Ted uses on his solar images. The only thing is the stars look a little off circular and jagged (only a minor point though and the detail of the nebula over powers this anyway, I have become obsessed with star shapes with in the last year and see defects every where now; a product of a stressed experience with the AG12).

In any event an amazing image of this oft imaged target.

[Peter Ward]

Thanks Paul. Believe it or not I did not de-convolve the data, though I do employ localised contrast enhancement to give low contrast features more snap.

The stars in the original .fits files are symmetrical
but, I did have to mask the h-alpha star data which was problematic....it was too sharp :doh:

The h-alpha data had stars about 2x smaller than the RGB.

I don't think the "select highlights" tool I used to fix the mis-match did a perfect job, but without doing so the HaRGB blend had dark rings around the stars.

...hence I'm guessing the slight distortions you have picked up on are from that.

[Sunfish]

Astonishing really for an earth bound image. Maybe a minor point but keeping the stars in a natural way in addition to the detail of nebula is superb.

[Peter Ward]

Thanks Ray. I've just uploaded a very high quality .jpg version to the page with the same URL (http://www.atscope.com.au/BRO/gallery450.html)
to allow the pixel peepers (and, guilty as charged, I'm one of them) to have a better look with decidedly less .jpg artifacts.

Sorry not 4k...I don't do 4k for the web.. (Marcus will likely be crestfallen) , but no jagged .jpg stars. :)

[Atmos]

There have been a few topics over the years on CN in regards to image scale, contrast transfer (MTF), pixel size and the like. Although some of the mathematics in the discussions went over my head I could understand enough of it.

In astrophotography there are two types of sources, point (stars) and non-point (everything else!). As apertures increase so does light intensity from stars directly proportionally to the aperture increase. This is aperture flux and is spread over however many pixels your FWHM is.
Non-stellar objects like galaxies and nebulae are a function of pixel size and focal ratio. With this were flux per square arcsec of sky is important.

What this means is that stars saturate slower in smaller refractors than larger reflections BUT both being able to image just as deep into a nebula with the same integration time. This is what makes wide field astro graphs (FSQs, flat field APOs, photographic lens') so good at what they do. They can image bright stars, fainter stars, galaxies and nebulosity in one exposure easier than a larger aperture.

So why don't the 80-130mm refractors or even 8-12" reflectors generally come as sharp as what Peter has posted? Seeing conditions is definitely a big part of that. Mostly though, it's aperture. What aperture allows is for you to image at a higher scale while maintaining SNR and therefore contrast. Contrast by definition is how well defined brightness differences are at small and large scales.

Take an 8" F/4.25 with ASI183 (close to yours Lee) and a 16" F/8 and PL16803.
Both image at 0.58"/pixel but as we're mostly talking about non-stellar objects (contrast in the nebulosity) we only care about pixel size and focal ratio.
2.4^2/9^2 = 14x more light per pixel
8^2/4.25^2 = 3.54x less light concentration

The larger aperture gets 3.95x more flux per square arcsec because the 16" is sucking in 4x the amount of photons as the 8" AND they're imaging at the same image scale.
Replace the ASI183 with a KAF-8300 and its 5.4 micron pixels and the situation changes where the smaller aperture ends up with 27.4% higher SNR with the same integration BUT it's now doing so at 1.31"/pixel. What this achieves is stronger signal on the fainter structures further out from the core of M42 and better contrast on the large scale structures BUT without the resolution to capture those small scale structures anymore.

[Peter Ward]

Thanks for your analysis .....also as a post script...I guess it was not too shabby as the image picked up a gong at this year's CWAS/Malin awards :cool:

[Atmos]

Congratulations :thumbsup:

Something else that Roland brought up a few years ago that surprised me was that seeing and optical errors are additive. I’d always imaged that as long as optical quality was below 3x seeing that it would be swamped by seeing error but if take it as additive then optical quality helps reduce seeing error to some degree.

For most people a Celestron Edge14 doesn’t need to have better optical performance than 15-20 microns on-axis for local seeing but apparently if that’s dropped down to 5 microns on-axis, even though WELL below seeing for most of us, helps cut through the seeing to some degree.

[astroron]

Not much that I can add to all the other comments,
except to say"Absolutely Fabulous"
Thanks for posting Peter.
Cheers:thumbsup:

[Peter Ward]

Thanks. My pleasure.



Ta.

Indeed, stands to reason, to use a cup of water analogy if the optic is barely diffraction limited (i.e.full to the brim) , then *any* seeing perturbation will cause light spill. If the cup is a bit deeper, the things can slosh about a bit before the cup spills.

[gregbradley]

Congrats on the gong. I thought it would.

Greg.

[Peter Ward]

Ta...actually got two, that and a wide field, but won't know (as usual) how they rated until the awards night next month....many great imagers in Oz these days, hence my expectations are modest..

[gregbradley]

The 60Da image right? As soon as I saw it I thought that's going to get that category.

Greg.

[Peter Ward]

Sorry Greg, missed your post. Yes, a version of that pano got a nod...but
best guess is an HM.....but we'll all find out on the 19th!

It was not that hard to do. Despite passing clouds, the skies were remarkably dark (passing clouds were darker than the sky) I just clicked away.

No guiding at all (used the starlapse) also have to say Sigma's 105mm F1.4...which has a 90mm objective...just sucked up the photons and is amazing bang for buck. :thumbsup: