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petershah
27-07-2023, 02:50 AM
I know this is bread and butter for most of you guys down South, However for us Northerners its a bit of a challenge not getting very high up. It is one I have been chasing for many years and although I have imaged it before its always been a bit of a let down as far as detail is concerned....

This was a first data set from a 16in Dall-Kirkam I stripped, rebuilt and fitted in our observatory in Spain, Its been a bit of a journey if I'm honest....it gave really horrible stars before I managed to sort it..

2hours each in RGB all 180s subs unguided 2720 fl....pretty optimistic over sampling the idea was to software bin if needed....I felt with the sheer volume of frames it was ok and a lot of it could be recovered with deconvolution, rejection in stacking and sharpening etc...

I lent toward the more pink hue taking advantage of its high blue signal, the idea being closer to the colour we see in HII regions in galaxies.....

Anyway enough of the waffle and thanks for looking

Peter Shah

https://astrob.in/j9al6e/0/rawthumb/hd/get.jpg?insecure (https://astrob.in/j9al6e/0/)

Dave882
27-07-2023, 11:45 AM
Lovely detail revealed so you’ve done well with imaging this fairly low in the sky. :thumbsup:

Mickoid
27-07-2023, 12:54 PM
I'm not sure if I'm more impressed by the detail you've captured from your northern location or the fact that your 3min subs were shot unguided @ 2720mm! That's a large scope you have there Peter, so I can only imagine the mount it sits on must really be impressive. Fantastic result which many of us from Down Under would be extremely proud of if we'd shot it from our southern skies.

strongmanmike
27-07-2023, 12:59 PM
A wonderful result Peter, quite crisp looking :thumbsup: ...has a real Spanish flavour to it :P

Arriba!

Mike

Retrograde
27-07-2023, 01:20 PM
This is excellent Peter.
Fantastic detail in those pillars and lovely broadband colours. :thumbsup:

petershah
27-07-2023, 05:54 PM
Thank you Dave...yes I started it at around 26 degrees, maximum hight was 38....so still enough atmosphere to take the edge off.

Thank you, M16 is one of those I've wanted to do since I started imaging back in the 80's, even before HST, but never managed to get one I was happy with...The scope is on an ASA DDM85, it's a stunning mount. It has direct drive so no gears at all, incredibly accurate and can throw around 100Kg like its nothing. The problem is getting a good enough model to to run unguided. Its been quite a lot of work but it will reliably do 300s unguided every night and with Cmos you don't want to be doing any more than that to get the best S/N, Quite different to CCD (but that's another debate) took a while to get used to that me being a dinosaur.

Muchas Gracias Amigo!!, too sharp??? when you really pixel peep I think bordering on acceptable. When I look closely there are some artefacts creeping in. I just couldn't help pushing just a little more I think driven by the desire to get a 'sharp enough' Eagle, deconvolution and wavelet sharpening did well to recover some of the seeing. At the moment I am building a 20in which will be going to Chile so I might get a better chance there....the seeing is steadier and M16 should be nicely placed.

Thank you, I know I've possibly tipped the scales on colour balance siding more towards a pinker tone, but I know the object well enough to know it's quite high in its blue signal.

Peter Ward
27-07-2023, 06:19 PM
Very tidy indeed....superbly processed and the stellar profiles are
as tight as a drum.

Nice one :thumbsup:

gregbradley
27-07-2023, 07:30 PM
That's incredibly sharp and detailed. Gee, the standard for images these days is sky high.

I am looking forward to beginning imaging again with construction on my new observatory starting very soon.

Greg.

petershah
27-07-2023, 10:51 PM
Thank you

Technology and processing has moved one significantly... Cmos has really improved imaging...the shear volume of frames means less influence through seeing...easy to reject the odd really bad frame and the modern stacking algorithms with their very powerful rejection methods basically bringing out of range pixel values back into range based on the average...

I have a (very clever) friend doing some measurements at the moment based on our systems in Spain....so far the signal to noise is favouring the shorter subs....He still hasn't finished his findings but on the one pier we have assigned there are early indications that just less than 1hr of 30s subs gives the same as 3hrs of 180s subs....its actually incredible....the big down side is that the time it takes to dither and the storage of huge numbers of frames, not to mention the processing power needed....there still lots to do with it including variable signal strengths etc.... cant wait to see the whole findings

markas
28-07-2023, 03:04 PM
Very nice result, Peter. Detail is splendid:thumbsup::thumbsup:
Mark

petershah
28-07-2023, 10:08 PM
Thank you Mark

TrevorW
29-07-2023, 12:05 PM
Excellent :)

rmuhlack
30-07-2023, 12:17 PM
That is super sharp and smooth. Detail is incredible

petershah
30-07-2023, 07:46 PM
Thank you


Thanks....I was surprised how much detail I was able to pull out especially as it only peaks at 38 degrees from my location....I will attempt it again from the Southern hemisphere one day.