I am on target and using live stacking...

Discussion of using SharpCap for Deep Sky Imaging
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DiligentSkies
Posts: 52
Joined: Wed Dec 02, 2020 10:46 pm

I am on target and using live stacking...

#1

Post by DiligentSkies »

Hello Robin,

Things are falling in place for me.
I am on target and capturing some great subs of the Flame/Horseheads Nebula.

Using your histogram brain analysis. I will post later some screen shots of these smart histogram tabs. Since for now, I am stacking. I don't want to pause the stacking.

In the guiding tab, I am dithering and have reasonable guiding (Can it be improved, YES!!!)(Most of PHD2 data is within 2 degrees with some out liners that jump above this.
Y:+/1 4"
Y:+/1 4"
PHD2 Capture.PNG (44.13 KiB) Viewed 597 times
So I am reasonably guiding and using dithering with these settings...

In the past when I went to DeepSkyStacking and do a review of my subs I see a periodic issue where the some sub have not settled down and I get elongated stars. I just throw them out.

With my current capture parameters...
Camera Settings.PNG
Camera Settings.PNG (7.38 KiB) Viewed 597 times
The question I have is, "What dither interval, minimum settle time and maximum settle time should I be using to cynic the dithering with the goal of not capturing the subs with bad data.
Currently, I am dithering on every fourth sub or there about.

However if my goal should be to dither every sub(dither or die). If so, how does that change the minimum and maximum times I am setting so everything cynics up.

If dithering on every fourth sub for this exposure length is reasonable, "What values should I be setting, so again everything cynics up.

Sincerely,
Mark
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SmartCap Guiding.PNG
SmartCap Guiding.PNG (40.46 KiB) Viewed 597 times
nexusjeep
Posts: 293
Joined: Thu Oct 18, 2018 3:01 pm
Location: Gloucestershire

Re: I am on target and using live stacking...

#2

Post by nexusjeep »

I think PHD signals when it has completed the dither so SharpCap knows it is guiding again as sharpcap changes to the 1ms subs until dither is indicated as complete. On my setup I get different numbers of the short guide frames so it tends to suggest that sharpcap is waitng for PHD to confirm this or the number of guide frames would be consistent.

I am no expert but I dither every 4 to 5 frames up to about 1min sub lengths and play it a bit by ear afterwards so if I was running 5 min subs I would probably dither every one 2-3min subs probably every two but also depends on how long I am imaging. Sharpcap never used to shorten the exposure so you used to lose a real frame were as with the new setup this is not an issue so you can dither every frame if you feel it necessary.

Cheers
Nick
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Re: I am on target and using live stacking...

#3

Post by admin »

Hi,

your settings for the dithering options all look good except that you need to tick the very bottom option to reduce the exposure that SharpCap takes while dithering. This will cure the problems that you have with frames with elongated stars as SharpCap will switch the exposure to 1 second while the dithering is in process and switch it back again once the dithering is complete.

Cheers, Robin
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