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Old 14-10-2018, 11:58 AM
garymck (Gary)
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How is this?

Hi,
In another thread I bemoaned the severely light polluted area I lived in, and frankly I was just about ready to give up. Instead I thought I'd give it another go and produced the attached image of NGC253. Given the conditions I live under, what do you think of this image? I'm asking for an evaluation of whether you think this is a reasonably worthwhile result. Would it be enough for you to keep going? I'm beyond being able to make a reasonable evaluation myself. Some of the background noise is coming from jpeg reduction. The whole thing could probably with 2-3 times the data.

Details:
Sky had high mist reducing transparency (as usual)
ASI071MC Pro, -10 deg
63x2min exposures, no calibration (camera doesn't need darks)
Esprit 100mm refractor.
Image is a crop from the frame

cheers
Gary
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  #2  
Old 14-10-2018, 12:25 PM
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billdan (Bill)
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Hi Gary,

For 2 hours of data in a light pollution zone the image looks OK to me, sure another 4 hours on top will make it look smoother and brighter. There are a few dark spots and a hint of vignetting so taking flats will help sort that out.
I would also suggest dithering each sub frame which will reduce the background sky noise.



Cheers
Bill
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Old 14-10-2018, 12:31 PM
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lazjen (Chris)
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Assuming you don't want to really give up, then you just have to accept when living in a high LP area that you just need to collect a lot more data.

For this image you're at a bit over 2 hours and you mention needing at least 2 - 3 times the amount. I think that's a good start and you probably need a lot more.
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Old 14-10-2018, 12:56 PM
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LewisM
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Looks fine to me Gary!

Lots of imaging you can do in LP - I've been doing TINY PN's lately. No trouble really.

Here's 8hrs data in a sordid LP area: https://www.astrobin.com/full/343506/G/
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Old 14-10-2018, 01:03 PM
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blink138 (Pat)
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Quote:
Originally Posted by LewisM View Post
Looks fine to me Gary!

Lots of imaging you can do in LP - I've been doing TINY PN's lately. No trouble really.

Here's 8hrs data in a sordid LP area: https://www.astrobin.com/full/343506/G/
and you do not use an LP filter lewis?
pat
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Old 14-10-2018, 01:10 PM
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Ryderscope (Rodney)
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Hi Gary,

General observations and good things I see about this image ...
- Good colour lurking about in the core of the galaxy and a reasonable hint of the red coming through from the Ha regions in the spiral arms
- Stars look round across the field of view, maybe a tiny bit soft but hard to tell at this image scale
- Very slight vignetting (a tiny bit darker in the corners). Nothing that cannot be addressed quite easily with some flat frames
- Background a smidge too bright but after application of flats and histogram black point adjust should all be good
- Slight contrast increase would be good to show delineation between light and dark areas.


So yes, stay with it, more data - apply flats - adjust black point in histogram - some minor sharpening - colour saturation boost - increase in contrast with curves.

Of course I must close with saying that Pixinsight is very good at all of the above
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Old 14-10-2018, 01:21 PM
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LewisM
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Quote:
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and you do not use an LP filter Lewis?
pat
Nope. Only filter I use OSC imaging is UV/IR (67mm, screwed onto my drawtube extensions). With mono, I don't have any filter ahead of the filters.

PixInsight routines fix all my LP issues. Good calibration sets also help fixing images significantly.
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Old 14-10-2018, 01:49 PM
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RD400C (Garth)
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Hi Gary
You know if this image was produced 50 years ago by a guy in is back yard in a light polluted region through a misty overhead, with a 100m refractor, this would be front page news

Yep keep going I'm not even close to being skilled in AP but the fact that you can pull the data and create such a detailed and beautiful image is fantastic

Just looking at a complete galaxy and attempting to comprehend what we are able to see is also quite amazing

Keep going
Garth
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Old 14-10-2018, 01:51 PM
garymck (Gary)
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Hi Guys,
thanks for the encouragement....

I had got to the stage where I was unable to evaluate whether what I was doing was OK or not. Just needed some others to say it was OK given conditions. Lewis, that image is very encouraging - I'll see what I can do with more data.

Feeling a bit better about it now :-)

cheers
Gary
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Old 14-10-2018, 04:32 PM
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silv (Annette)
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Honestly? That image would make me proud as a beginner anywhere. But not as the result of the imaging time and $$$ you have invested.

It depends on from where your pleasure (and displeasure) comes.
My pleasure in astrophotography doesn't come from spending money after detailed consideration and acquiring knowledge about bits and peaces I need to buy, nor from DIY improvement projects. Or from pushing a button to my fully automated setup in an obs.
My pleasure in AP comes from taking out the loupe and investigate and understand what's visible, afterwards.

That's why your Sculptor result wouldn't encourage me to continue, at all. No joy in it for me. If it were the very beginning of the road for me, the very first imaging result, I'd continue 'cause there'd be hope I could approach a quality level which gives me the joy described before.
But you've been "at it" for 10 years now as a search in IIS shows, going through the Deep Space forum threads you created over the years.

So here's my question: what exactly did you enjoy most in those past 10 years? Was it the DIY part of the hobby? Or the technical thinking required in handling in mechanics, optics and post-processing software? Or was it the moments when you first pushed the curves in PI on a dark stack and the colourful, wispy details of a PN appear and give you an endorphin kick?

Those are mere examples I can empathically imagine. I'd suggest you ask yourself and find answer[s]: what are the details that gave or give you joy in astrophotography?

'Cause what your other thread and this one make me think is that the rational side in you is willing to give up an annoying part in your life but the addict in you (the one in search for that endorphin kick) is not letting go.
Don't let the addict in you get addicted to the "annoyed neurotransmitters" cause that would lower your psychological wellbeing in a fundamental way, making your inner addict addicted to depressing actions to get the kick out of depressing neurotransmitter.
Go and find out which moments or areas a really giving you pleasure. From that knowledge, a future hobby will show itself. One that'll give you joy and appease the addict in you with positive brain chemicals.

Sorry for the long read and bad English. But I really think my viewpoint here is valuable just because it's so different from the others'.
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Old 14-10-2018, 07:40 PM
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Atmos (Colin)
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So far it has come out pretty darn good Gary. You've got a lot of nice detail, a bit devoid of colour in the outer spiral arms but that isn't unusual in this galaxy. That could also just be jpeg compression that is destroying some of the colour too
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Old 14-10-2018, 08:32 PM
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I started on same object with the same camera in suburban Sydney before the rain came. I've got a bit over 2 hours and it looks much the same as yours. And I'm thinking I need a lot more on it. All good fun!
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Old 14-10-2018, 08:42 PM
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Hi Gary,

A bit noisy but a bit more integration time and step up the processing a bit and it would look damn fine...

Cheers,
Rick.
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