Is it possible with 3.3 to dither without guiding and no live stack?

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Menno555
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Re: Is it possible with 3.3 to dither without guiding and no live stack?

#11

Post by Menno555 »

Hi Robin

Great to hear! Will see what happens with the sequencer!

Menno
RickBG
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Re: Is it possible with 3.3 to dither without guiding and no live stack?

#12

Post by RickBG »

Hi Robin,
I had downloaded the latest version of SC where you incorporated the ability to dither without guiding. I'm so new to dithering that I have several questions but first you might need to know the type of scope & camera I use: CPC 800 SCT (Altaz) and ZWO ASI183 C. Under SC settings > hardware, the mount is set to CPWI (by Celestron). Also the box is checked for dithering without guiding. I am connected to ASCOM (through CPWI)
1. Do I need to download any other software to dither?
2. Do I need to make any connection from the camera to the mount as if I'm guiding?
3. Does SC automatically dither when "dithering without guiding" box is checked?
4. Can dithering take the place of taking dark frames because it is suppose to reduce noise?
5. Can dithering take the place of guiding?
Based on the questions above, you can sense I know nothing about dithering but I want to give it a try. Thanks.

Rick
chongo228
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Re: Is it possible with 3.3 to dither without guiding and no live stack?

#13

Post by chongo228 »

RickBG wrote: Fri Mar 12, 2021 11:24 pm Hi Robin,
I had downloaded the latest version of SC where you incorporated the ability to dither without guiding. I'm so new to dithering that I have several questions but first you might need to know the type of scope & camera I use: CPC 800 SCT (Altaz) and ZWO ASI183 C. Under SC settings > hardware, the mount is set to CPWI (by Celestron). Also the box is checked for dithering without guiding. I am connected to ASCOM (through CPWI)
1. Do I need to download any other software to dither?
2. Do I need to make any connection from the camera to the mount as if I'm guiding?
3. Does SC automatically dither when "dithering without guiding" box is checked?
4. Can dithering take the place of taking dark frames because it is suppose to reduce noise?
5. Can dithering take the place of guiding?
Based on the questions above, you can sense I know nothing about dithering but I want to give it a try. Thanks.

Rick
To answer your questions...
1. Depends on your setup. You need SC to be able to talk to the mount but shouldn't need anything else to do an unguided dither
2. No, funnel everything through SC.
3. Someone else will have to answer this
4. No, they compensate for different types of noise
5. No, dithering is to stop some types of noise. Guiding keeps your stars tight and allows for longer exposures. They are two different things.
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Re: Is it possible with 3.3 to dither without guiding and no live stack?

#14

Post by admin »

Hi,

to fill in the blank (thanks @chongo228)

3) As well as selecting 'Dither only (No Guiding)' in the settings, you need to tell SharpCap that you want to dither - either in live stacking or using the sequencer/sequence planner. Just running a 'Start Capture' will not dither.

cheers,

Robin
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Menno555
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Re: Is it possible with 3.3 to dither without guiding and no live stack?

#15

Post by Menno555 »

Robin

I never use the Live Stacking, so 2 questions if this scenario will work when using that with dither:
1) I now that you can save individual FITS files while live stacking, but does Live Stacking work without calibration files?
2) If a capture is refused by the Live Stacking (for example not enough stars to work with), will it still save that capture as FITS or is it discarded all together?

Menno
chongo228
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Re: Is it possible with 3.3 to dither without guiding and no live stack?

#16

Post by chongo228 »

Menno555 wrote: Sun Mar 14, 2021 9:43 am Robin

I never use the Live Stacking, so 2 questions if this scenario will work when using that with dither:
1) I now that you can save individual FITS files while live stacking, but does Live Stacking work without calibration files?
2) If a capture is refused by the Live Stacking (for example not enough stars to work with), will it still save that capture as FITS or is it discarded all together?

Menno
1) Yes, it will work with or without dark/flats.
2) If you have "Saved all files except when dithering" selected it will save everything, even if clouds come and ruin your night.

Just a note about my process that might help you...
I always use live stacking. Unless you need to save processing power I don't see a reason not to use it. It does everything start capture can do and more.

Even when I'm inside on the couch I use live stack. I usually set it to clear and start a new stack every four or five frames so I can monitor the most recent images when I go outside to check. This helps me catch thin clouds or being out of focus. I use it more as a way to monitor quality of images and less of an EAA tool....but it does help time go by faster to have something cool to look at when I'm babysitting my rig . When I use it as a quality tool I don't do any preprocessing to it except for stretching the histo. I could use start capture to inspect quality of images but Live stack has all the histo tools I need right there and is so much easier. I prefer to have 3 or 4 frames stacked when I inspect so I don't break routine to focus or shut down due to clouds over one bad frame.

Spend a little time dialing in the settings. I have it set now so it works with all three of my refractors (small, medium, and large) and I don't have to adjust any settings. It's pretty robust once you have everything set right.
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Re: Is it possible with 3.3 to dither without guiding and no live stack?

#17

Post by Menno555 »

chongo228 wrote: Sun Mar 14, 2021 1:41 pm
1) Yes, it will work with or without dark/flats.
2) If you have "Saved all files except when dithering" selected it will save everything, even if clouds come and ruin your night.
Ah ok, good to know. Thanks!
For me it works better/more fun when using DeepSkyStacker, Siril and Photoshop.
For processing power it's not problem (i9-9900k, 32gb and RTX 2080ti) it's just that I like the way for processing more :)

Menno
chongo228
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Re: Is it possible with 3.3 to dither without guiding and no live stack?

#18

Post by chongo228 »

Menno555 wrote: Sun Mar 14, 2021 6:31 pm
chongo228 wrote: Sun Mar 14, 2021 1:41 pm
1) Yes, it will work with or without dark/flats.
2) If you have "Saved all files except when dithering" selected it will save everything, even if clouds come and ruin your night.
Ah ok, good to know. Thanks!
For me it works better/more fun when using DeepSkyStacker, Siril and Photoshop.
For processing power it's not problem (i9-9900k, 32gb and RTX 2080ti) it's just that I like the way for processing more :)

Menno
I guess I should have added that I don't use SC for processing. Live stack is simply a better tool to analyze incoming image quality compared to start capture mode. I only save individual frames to process later in Pixinsight.
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Re: Is it possible with 3.3 to dither without guiding and no live stack?

#19

Post by Menno555 »

chongo228 wrote: Sun Mar 14, 2021 8:04 pm I guess I should have added that I don't use SC for processing. Live stack is simply a better tool to analyze incoming image quality compared to start capture mode. I only save individual frames to process later in Pixinsight.
Clear. It's a kind of stacking preview :)
I do that always on the fly with DSS here: my gear is on my balcony and connected to PC with a 15 meter active USB3 cable (yep, I'm a cable guy :) ).. For langer exposures I don't have to dither but for 60 seconds or shorter, this really is a very cool feature.
So I am going to try it for sure. Thanks!

Menno
RickBG
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Re: Is it possible with 3.3 to dither without guiding and no live stack?

#20

Post by RickBG »

In SC settings, under guiding, there are a set of parameters for dithering. It first reads "use these parameter when SharpCap requires dithering". Are those four parameters at default and should not be changed or should they be changed for better or for worse depending on the circumstance? How are these parameters derived at? When doing live stacking there is a tab which reads "guiding" where you can check off the box for dithering and also gives you the number of seconds which showed up as 120 seconds which appears as a default. Should I leave this number of seconds or should I change it? I generally take very short exposures (1-4 seconds), therefore should I dither after every 5 frames or 50 frames or anything in-between? Is there a formula to get the best dithering experience ever? :D

Rick
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