December - NGC2237 - Comparison

[PKay]

The Rossette Nebula.

A faint & beautiful target.

My first attempt & challenge was just to find it...
And after many hours of imaging and processing, it appeared!

http://www.iceinspace.com.au/forum/attachment.php?attachmentid=219433&d=1507956375

So you lot, show us how it can be done!

And that includes you lot from deep space, just put in the links :)

[Mickoid]

I have never posted this first attempt of the Rosette, in fact I don't even remember the technical details of how it was produced other than it was with my Esprit 100 from the outskirts of Melbourne. I took it earlier this year ( around February ) and going by my usual efforts then, it would not have been more than 20 mins integration time using the modded Canon 550d at 1600 iso. Not much nebulosity but some reasonable star colours came through.

I plan to try this one again next new moon, if the rain stops! ;)

[skysurfer]

Nice photo.

I took similar photos with my unmodded 6d and the ED110.
Modern fullframe and APS-C cameras don't need modding anymore due to much better sensors and proper filters (UHC-S) do the remaining work in light polluted areas like my backyard. Despite only 20% of Halpha light is passed by the camera.

I got faint Halpha objects such as IC1396 (Elephants Trunk), IC1805/48 (Heart&Soul) and IC2944 (Running Chick) this way.

Otherwise I make an unfiltered photo and another Halpha photo with at least 4 times the exposure time per frame and after stacking I use the Halpha stack as an overlay over the nonfiltered stacked color photo.

Six constellations with a C contain the most Halpha nebulas : cas-cep-cyg---car-cru-cen.

[ChrisV]

I'll put up a work in progress. I got back my ASI071MC upgraded to the pro - wow I don't feel like one. But it now works nicely on a simple USB2 cable instead of those horrible stiff USB3 ones - no amp glow. Cooling worked well with no frosting on the sensor.

I've only been able to get 2 hours of 90sec subs (at unity gain on an 80mm refractor). Got it last week just before moonrise. Have since had lousy weather, so if I get more I will add to it.

Processed in pixinsight. Don't know if I got this right as when I calibrate the flats it comes up with an error that there's no correlation between the target and the darks (reading the PI forum it seems this is happening because the flats are under 1sec and don't need darks, just bias frames??). Its only done this with the bias/darks/flats from the upgraded camera (it doesn't do this on calibration files from the camera before I got it upgraded - and using same capture settings and PI preprocessing). Weird?

Also a question. I'm still a bit perplexed as to which denoising I should use. For this image I did the following -
- on the stacked debayaered image - I crop and DBE and then colour calibrate.
- reduce noise with ATrousWaveletTransform on the image with the foreground target masked.
- stretch
- TGCdenoise - mainly bringing up the black level
- then increase colour saturation with the background masked. And reduce the background a bit with the foreground masked
- and finished off with localhistogramequalisation
This is kind of following a mishmash of processes described on Harry's astroshed. Does this sound sensible?

http://astrob.in/326505/0/

[PKay]

Your image looks great, well done!
Lots of nice detail and contrast.

With regards to PI workflow - whatever works!
Do something, and then think better or worse.

All you need do now is get another 9 hours of data (nick over to deep space and have a look at Joel's image).

I have been waiting for the clouds to clear, and incredibly since I got back home (2 weeks now), not one clear night...

[PKay]

I have had similar things happen.
Then I switch to manual processing. It stops when it finds a faulty image. Then you look at the process console. It shows the faulty image. Remove it from the list and go again.

[ChrisV]

Now have two nights (13 & 24 Dec), nearly 6 hours of the Rosette Neb on ASI071Pro
Processed in PI. Only used bias frames, no darks (as they not very different from the bias frames).
Tried the convolution function but its a bit messy.

https://www.astrobin.com/327648/0/

[PKay]

Looking good Chris
The hi res at astrobin shows plenty of good detail.
Nice stars too.

Time for some one else to pick a target?

Oh, and Happy New Year!

PK