Well after a 5 month hiatus i am back at it with a target i have long wanted to go DEEP with. Centaurus A has a limited 4 hour window each night from my location so i have been piling on the data with the ASI.
A complete image is probably a few weeks away but i thought i would share what i have currently.
Details:
Mount: EQ6
Scope: 102mm F7 APO (Teleskop Express)
Camera: ASI1600MM
Filters: Astrodon E Series Lum
Image Integration:
409 x 30 second shots over one night (3.5 hours total with a further 7 hours awaiting processing.)
Gain: 50, Offset 21
It took 7 hours to process to a simple stack so this is just a stack with screen transfer function from PixInSight applied. As such data is undrizzeled etc etc.
I am thinking to speed things along about processing images in 100 shot packs then stacking these stacks together as my Computer is having conniptions compiling 400+ images.
Would that i could Peter, even with a gain of 0 on this camera i find i start getting full wells at about 1.5mins on bright targets. The noise that is there is because this is literally just stacked RAW data, no processing applied apart from an auto screen stretch.
Likewise i my master dark only currently has 9 frames at this setting so with more darks and flats i imagine the noise issue will resolve itself.
My real issue is compiling/stacking/preprocessing the data in the first place
Quote:
Originally Posted by Peter Ward
Given the aperture of the telescope this is a very impressive image.
I think you'd control the noise better by taking longer subs (say 3-5 minutes)
But still a good effort
Good start! I can relate to the time required to process the images from an ASI1600. It takes many hours to get the images through the pre-processing, etc. Currently, if I do just one target in a night and have several hundred images, it will take most of the next day to just get them through that initial phase. And if you need to tweak some settings, it can take days.
I'm currently planning to buy/build a new PC that's going to be optimised for Pixinsight processing of these images. While it was getting to the stage where I'd be looking at a PC upgrade sometime in the next year or so, the ASI1600 is effectively forcing me to consider it earlier. It also means that perhaps the true cost of the ASI1600 camera needs to consider the PC upgrades required. However, in my case I think I'll just let that slide.
A very nice Cen A Grady, with lovely natural colour , For what it's worth, just watch that decon (or wavelets), imparts a high res "look" at small to moderate image enlargements but becomes quite noticeable when looking more closely .
Nice work, Grady. You've had one small nit pick from Mikey, now here's mine There's some large scale red and blue colour noise in the background. It's not a big deal but desaturating it would lift the image a little.
Grady that is a great result. What a cracker of a scope! An image resolution that someone with a scope 3X your aperture would be proud of. I can't even imagine spending the time to process 400+ subs. My computer would have crashed after about 2hrs of processing! I like the subtle colours, it looks more natural. So often this object is over saturated to the point that it no longer looks real and more like an artists impression of it. Nice work.
A very nice Cen A Grady, with lovely natural colour , For what it's worth, just watch that decon (or wavelets), imparts a high res "look" at small to moderate image enlargements but becomes quite noticeable when looking more closely .
Mike
I only did 15 iterations of decon at default settings and no wavelet at all (unless i applied some for noise ??) lol
Quote:
Originally Posted by RickS;
Nice work, Grady. You've had one small nit pick from Mikey, now here's mine There's some large scale red and blue colour noise in the background. It's not a big deal but desaturating it would lift the image a little.
Cheers,
Rick.
I noticed that too. But i have yet to figure out a way of removing it (it appeared after i removed the green hue with colour calibration)
I noticed that too. But i have yet to figure out a way of removing it (it appeared after i removed the green hue with colour calibration)
Create a mask to protect the bright stuff and only expose the background (say with RangeSelection or HT manipulation of a copy of the luminance) and then use CurvesTransform to pull down the Saturation curve. It it still looks a bit lumpy then you can hit it with some noise reduction.
Have to be Happy with that, very worthy resulting image Grady
Isnt processing always full of capers, It's definitely what keeps me in this hobby
Excellent Depth in this Image Seeing a good number of faint background fuzzyy's & hows that 'S' shape Galaxies right down in the low right corner, ,
Very nice work & top show !!
) lol 
It's definitely what keeps me in this hobby 
