Live Stacks 10-30-2018

[BlackWikkett]

Clearest night in months we've had in northeast Georgia, USA. The following images were taken with SharpCap 3.2.5825.0 using Live Stack feature. All images posted are saved via "Save exactly as seen" save dialog in SharpCap Live Stack. No post processing was done. All adjustments made in SharpCap while stacking used "Auto Stretch," "Auto Color Balance" and "Display Histogram Stretch." While stacking also adjusted Red, Green, Blue and Saturation sliders in Live Stack histogram. As the images were stacking also tried various combinations in the enhancement tab in Live Stack. Tried adjusting the noise reduction and sharpening but both features were off for final image as they didn't make the images more pleasing to my eye.

Equipment: GSO RC6, ZWO ASI183MC Pro Bin2 , IDAS D1 LPS, .75 Reducer F6.8

- FWHM as measured in Live Stack was between 5.5 and 6.8 for individual exposures
- All individual exposures were 240 seconds, Bin 2, Gain 300, offset(ZWO Brightness) was 25-35, camera cooler set to -15
- 5x240s Master dark frame used for all images
- 30x Master flat frame used for all images


M27 Dumbbell Nebula 28 x 240s


NGC7380 Wizard Nebula 6 x240s Tried adjusting red balance in image control seems to have emphasized the 183's amp glow


Deer Lick & Stephan's Quintet 14 x 240s Tried some more tweaking of red balance less amp glow but not ideal


M33 Triangulum Galaxy 41 x 240s parked here for a while greenish cast on left side and reddish cast on right no amp glow settings seem dialed in


NGC1977 Running Man Nebula 17 x 240s was shutting down for the night didn't think much would come of this due to position of the moon, just parked the scope here until I was ready to brave the elements to tear down the rig. Nice surprise when I got back to the computer


Master Dark 5 x 240s


Master Flat 30 frames averaged

-Wikkett

[oopfan]

Running Man, very nice!
Just curious how did you decide on 240s exposures?

Brian

[BlackWikkett]

Running Man, very nice!
Just curious how did you decide on 240s exposures?

Brian

Started with the "brain" function in smart histogram to measure sky brightness so SharpCap could suggest gain and exposure times. Usually set the parameters in the brain for 1s to 60s and let it analyze. Tried several different capture settings up to 3 min. but the brain failed to find a solution. Slewed to the Dumbbell grabbed a single 4 min exposure at 300 gain with offset 25. Histogram and image looked reasonable in SharpCap. Then using the results of this test created 5x240s dark master and a flat and started the night Live stacking.

I've used the the ASI183MC Pro for well over 6 months now and It makes great images for OSC. But due to the small pixels, crazy amp glow I don't thinik it's the best for Live Stacking. It's the only cooled camera I have at the moment so I use it. ASI294 MC Pro is on the way and It will be much better suited for Live Stacking.

-Wikkett

[oopfan]

Curious about the Brain not converging. I wonder if the amp-glow is throwing it off. Have you tried selecting a rectangular region on the opposite side from the amp? It would be interesting to see what the Brain recommends. My experience is that it likes exposures <30s with my monochrome sensor and luminance filter. I prefer 50s-70s exposures. I can get same signal-to-noise with a lot less total integration time.

Brian

[BlackWikkett]

When I use the Brain function always use region of interest (ROI). I pick an area away from amp glow in a dark area of the image. I've tried different size ROI when Brain fails and also have tired different regions of the image. Next time I'll try longer exposure and integration time. Your mono cam has a lot more sensitivity compared to the color 183.

-Wikkett

[turfpit]

Wikkett

A good set of images - a satisfying reward for a long night's work. Thanks for posting the technical details, these should help point others in the right direction.

Dave

[turfpit]

Wikkett

How much difference does the IDAS D1 LPS make? it is certainly not a cheap filter.

Dave

[BlackWikkett]

The IDAS D1 is specially designed for OSC and does a really good job of knocking down a lot of the light pollution caused sky glow. I also have their D2 filter witch is designed to filter LED light pollution. I usually use the D1 as my observing site doesn't suffer from LED sources. I'm just a rookie in the hobby but have also used Astronomik LPS-CCD for DSLR (Canon T5i in my case.) No mater which LPS filter you use you will have to up exposure time by a factor of x based on what your camera is capable of. I've found this to be true for DSLR and my ZWO camera.

Here's a few sites you may be interested in:

Hutech interactive graphs for IDAS LPS filters https://www.sciencecenter.net/hutech/id ... /index.php

Quick review of the IDAS D1 with some nice comparison images https://www.lifepixel.com/photography-g ... ion-filter

My observing site is on the edge of Bortle 5 - 6 leaning more towards 6. I'm 45 minuets from downtown Atlanta and the light dome surrounding the city is massive. I wouldn't want to image without an LPS. The reason I chose the IDAS D1 was due to results I witnessed the guys on NSN getting with them.

-Wikkett

[turfpit]

Thanks Wikkett. My sky splits into 2 around the meridian. To the west I get the light dome of Manchester (UK) and the surrounding conurbation. To the east I have the dark of the Pennine Hills. I try to concentrate on objects in the east. Might have a look at getting an IDAS filter. Due to my recent experience with Ha, I understand having to up the exposure (I think x=10 or more for this one).

Thanks for the info and the links.

Dave