<<I’d be very interested to know how Light Pollution is factored into the resolution equation. After seeing some results from others I’d be keen to try and hit some PNs (or even galaxies) lucky imaging with my c14 but feel I may be restricted by B6/7 LP at my location limiting me to only the brightest targets.>>
Dave,
I tried to get the PN in M22 - from light polluted GoldCoast.
Used IDAS LPS filter 85x30s High Gain 2, offset12, 0degrees.
Crop is ok but no PN seen - Ive yet to go to the higher gain/shorter exposure Alex is using. Less bloat at least...
Alex is lucky enough to live in a very dark location, far away from light sources. This provides an environment to experiment, off of a dark baseline, which is not available to many others. Photon arrival rates, during very short subs, would simply be lost in the light dome of major population centres, no matter how you try to filter it.
Here’s a couple of Galaxy images from Tokyo City Bortle 9 white zone from Cuiv using lucky imaging with his 8” Newt and EQ6 mount
Exposures were 10 sec and 30 sec , hundreds and hundreds of subs
Absolutely incredible what can be achieved in the worst kind of conditions for AP
Resolution is poor due to being copied from a website ( grossly downsized )but you can see the level he can achieve with just basic equipment
Astounding !!
Scroll down to image processing, Stefan did a great job of writing it all up, Mainly each sub needed to be run through multiscale gradient correction to remove any gradients caused by light pollution, It chews some CPU, but it preserves fainter details better,
I hadn't heard of this before, deep sky lucky imaging, very interesting indeed. On reading up, the recommended gain setting for a CMOS cam is 350-400 (low read noise). the well depth at 400 is then essentially 8 bit, 256 levels, I understand very short deep sky exposures will not need much dynamic range, but 8 bit ?(pre stretch), that's scary !.
Also, why, instead of manually selecting best subs out of 1000s isn't something like registax planetary software used that automatically grades and selects the sharpest bits of every sub instead of whole subs only.
If there is a reason this kind of application is not appropriate, Ive been testing an automatic way to have the sharpest subs graded (on DS subs, only sharpness nothing else, may not be sufficient) looking promising!.
I am trying 15 seconds at gain 350 and 450 using the 115 mm and so far it seems ok..I hope to try shorter thru the RASA tonight but the irony is the seeing has greatly improved such that long exposures should work again.
Still dew but you are not swiming in it.
So I have three guide scopes and cameras that again seem useful..I will fit them all today if I get time but the RASA fittings need some more angle grinder work and although that is fast smoothing after takes ages...
Unfortunately the fog set in later last night so just for fun I had a peek at Orion and it was bright enough to get an image at 1s even with the fog. I was surprised could resolve the bright center stars. I decided to give this a go for fun. Took ~1300 x 1s, ASI1600MC-c gain: 139 offset 25, -10C, no filter. Tried gain 75 and 200 and 1,2,3,5s but settled on 139 & 1.
Stacked 80% in DSS, no calibration. Nina was only grabbing 1 frame every 6-8s so I turned off most of the post processing fluff (except HFR/stars) and got it down to 1 every 2s. Given how the stack blew out the core if I have another go I'll try much lower exposures ~0.1s
I know as an image of Orion it is "decidedly average" but that's not the point
Watching the live stack was soo cool. Noisier! noisy - better...
Unfortunately the fog set in later last night so just for fun I had a peek at Orion and it was bright enough to get an image at 1s even with the fog. I was surprised could resolve the bright center stars. I decided to give this a go for fun. Took ~1300 x 1s, ASI1600MC-c gain: 139 offset 25, -10C, no filter. Tried gain 75 and 200 and 1,2,3,5s but settled on 139 & 1.
Stacked 80% in DSS, no calibration. Nina was only grabbing 1 frame every 6-8s so I turned off most of the post processing fluff (except HFR/stars) and got it down to 1 every 2s. Given how the stack blew out the core if I have another go I'll try much lower exposures ~0.1s
I know as an image of Orion it is "decidedly average" but that's not the point
Watching the live stack was soo cool. Noisier! noisy - better...
Thanks for contributing John..may I suggest a little "cheat" ..give your core a light touch up with the "burn" tool from either photoshop or Gimp ( free and for most purposes as good as photoshop) ...the burn tool selectively darkens an area and I suspect a gentle application may bring out four little stars...maybe...but it is a handy tool for situations where you need to brighten or darken just part of an image...
Cheers for the tip, never even heard of it. I was trying at higher gains to play with that concept but anything above unity sucked. Need to go shorter, by a lot I'm guessing, on such a bright target. I don't care if it amounts to anything: it's fun just trying it out
Unfortunately the fog set in later last night so just for fun I had a peek at Orion and it was bright enough to get an image at 1s even with the fog. I was surprised could resolve the bright center stars. I decided to give this a go for fun. Took ~1300 x 1s, ASI1600MC-c gain: 139 offset 25, -10C, no filter. Tried gain 75 and 200 and 1,2,3,5s but settled on 139 & 1.
Stacked 80% in DSS, no calibration. Nina was only grabbing 1 frame every 6-8s so I turned off most of the post processing fluff (except HFR/stars) and got it down to 1 every 2s. Given how the stack blew out the core if I have another go I'll try much lower exposures ~0.1s
I know as an image of Orion it is "decidedly average" but that's not the point
Watching the live stack was soo cool. Noisier! noisy - better...
So how did it compare, John? Were the stars smaller? Was there less noise? Just curious what gains were had. My understanding with the video posted earlier in this thread was that it was supposed to bring out fine details.
