Dithering in Sequencer

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ColinR
Posts: 37
Joined: Fri Oct 12, 2018 1:20 pm

Dithering in Sequencer

#1

Post by ColinR »

Hi,
I've been looking through the posts but can't find what I am looking for.

My problem is that during a dayligh run, (not a daylight test run), dithering does not seem to happen. I am trying to learn the Sequencer, so I am doing a lot of testing indoors. I use a pylon about one kilometer outside my study window for near focus, with EQMOD Tracking Off.

I think that I have set Dither only and put in large numbers in both PHD2 dither setting scale and SC Settings, (PHD2 Scale 6, SC 10 on 1:2.7 guiding/imaging ratio), but there seems to be no movement between any of the 60 short daylight images that I take of the pylon. (Should be around four dithering movements.) No doubt I'm misundersting something,

Any help would be greatly appreciated.

Colin
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Re: Dithering in Sequencer

#2

Post by admin »

Hi Colin,

when I wrote the dithering support in the sequencer, the 'dither only' guiding option did not exist, so dithering relied entirely on PHD, which obviously needed stars. For that reason, dithering is disabled in the daylight test because it will not work.

However, you can test dithering - PHD2 has a 'Simulator' camera - choose that and 'On Camera' for the mount in PHD2 and you can get it running happily in simulated guiding and have SharpCap dither for you if you do a night time test run (disable focus, etc).

cheers,

Robin
ColinR
Posts: 37
Joined: Fri Oct 12, 2018 1:20 pm

Re: Dithering in Sequencer

#3

Post by ColinR »

Thanks Robin, much appreciated.
ColinR
Posts: 37
Joined: Fri Oct 12, 2018 1:20 pm

Re: Dithering in Sequencer

#4

Post by ColinR »

Hi again,

I have set up a Simulator PHD2 profile as suggested and this works. However I can see no dithering when running the sequencer. Please see attached files (PHD2 and Sequencer settings), in the hope the the mistake I am making is obvious to an experienced eye.
The PHD2 Dither settting is set to Random, Scale 10. (Along wit the the Sequencer setting of Max Dither Step is 10. This should have provided an obvious movement following a dither. I did not see any dither movement in PHD2 either.)

Again, any help would be grately appreciated.

Colin
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Re: Dithering in Sequencer

#5

Post by admin »

Hi,

because you have selected the 'Dither only' option in the SharpCap settings, SharpCap is dithering by sending small movement requests to your mount. PHD2 in simulator mode will know nothing about this, so you will not see any dithering in PHD. You should see the mount co-ordinates shift slightly at each dither.

Note that if you ran this setup for real PHD would see the dither operation as a problem with drift and then correct it back to the original position, meaning that the beneficial effect of dithering would be lost.

cheers,

Robin
ColinR
Posts: 37
Joined: Fri Oct 12, 2018 1:20 pm

Re: Dithering in Sequencer

#6

Post by ColinR »

Thanks again Robin.
I will check this out using EDMOD to look for movement. Regardless of the outcome I will carry out a real imaging session and hope that all is OK.
I will use a proper profile for my setup. I should see the movements when I look at my files in PI Blink.

Thanks again for your help.

Colin
ColinR
Posts: 37
Joined: Fri Oct 12, 2018 1:20 pm

Re: Dithering in Sequencer

#7

Post by ColinR »

Robin,
Just to say thzt the PHD2 and SharpCap movement setting will be set to give my 30 pixel moves on my Imaging scope/camera.

Colin
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