A brief introduction to the SharpCap Sequencer

Discussions, Bug Reports and Issues related to Beta versions of SharpCap
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Re: A brief introduction to the SharpCap Sequencer

#101

Post by admin »

Oh, one more thing…

If you have the Ascom platform installed then you will find that there is at least one Ascom ' Simulator' camera available. If you use this rather than SharpCap's built-in test cameras you may find that you can try out the cooling features, since I think the Ascom simulator has simulated cooling support.

Cheers, Robin
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Re: A brief introduction to the SharpCap Sequencer

#102

Post by Moorefam »

Robin,
It would be easier for me not to use the sequencer as when at the stage of having plate solved, set the guiding (MGen 3) camera cooling, gain, exp and No of images etc I let everything run the only problem then is correcting focussing. I know roughly how many steps I need to apply with my EAS focusser, in which direction, per degree C (from the temp sensor). Instead of having to set everything up in the sequencer, which I may well have to abort quickly because of cloud/showers,meridian flip etc it would be nice if another block was available in the RHS menus to include one that applied 1 step change in focus in or out for every x change in temp (probably 1 C). It would be best to occur between camera frames.

Do I have to use the sequence editor to set auto focussing to occur say every 30 camera frames? I am not quite sure of the looping in the coding.

As an aside as I understand it with MGen3 dithering occurs between camera frames?
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Re: A brief introduction to the SharpCap Sequencer

#103

Post by admin »

Hi,

actually, the offset of focus position as the temperature changes is something that the ASCOM driver for a focuser can choose to provide - if it does then SharpCap will show a 'T. Comp' checkbox that allows you to turn it on or off. Typically if it is provided then there is an option somewhere in the focuser setup window that allows you to specify how much it moves per degree C. The trouble is that this functionality is optional, and it's quite possible that the developers of your ASCOM driver didn't bother to implement it :(

If I was going to do this in SharpCap then I might well do the same as I have with backlash compensation - ie have the option of 'let the ASCOM driver handle it' vs 'let SharpCap handle it' vs 'nothing' in the settings - then it would be automatic in all circumstances, not just inside the sequencer.

If you do want to refocus in the sequencer, you can do it in the planner with a little cunning - you have to take advantage of the fact that the planner can be set to refocus on filter changes. If you are using a filter wheel then cycle through the filters (5 lum, 5 red, 5 blue, 5 green, etc) and repeat 4 times rather than 20 lum, 20 red, 20 blue, etc. Each filter change will trigger a refocus.

If you are not using a filter wheel then set up the ASCOM simulator wheel (which obviously does nothing), and capture 10 frames with filter A and 10 with filter B, then repeat - again triggering a refocus on each filter change even though nothing really happens.

And the MGEN, yes, dithering should be between frames only.

cheers,

Robin
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Re: A brief introduction to the SharpCap Sequencer

#104

Post by Moorefam »

The temp adjust focus box does appear in Sharpcap but is greyed out and there is nothing I can see that will change that. That is a pity as applying a focus change of x steps/ degree C would be very useful.
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Re: A brief introduction to the SharpCap Sequencer

#105

Post by admin »

Hi,

if the box is greyed out, it almost certainly means that your focuser ASCOM driver doesn't support that functionality :( You will need to talk to the manufacturers of your focuser to see if they can be persuaded to update the ASCOM driver to support temperature compensation.

cheers,

Robin
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Re: A brief introduction to the SharpCap Sequencer

#106

Post by Moorefam »

Robin,
I am getting to grips with the sequencer starting with the autofocus using the ZWO EAF auto focusser. Using autofocus manually I have noticed that a good number of images at each focus point are needed for the s.d. to minimize, otherwise the 2nd order curve can develop higher orders and this makes the focus point inaccurate. The autofocus doesn't seem to wait to take a number of images at each focus point? Would it be an idea to enable a box to select how many points are needed for each focus point? Also wouldn't it help to start from the approx focus point, scan focussing inward to the limit point, then scan outward to the other limit then back to the original point again?
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Re: A brief introduction to the SharpCap Sequencer

#107

Post by admin »

Hi,

the autofocus tool should use the number of samples at each point that you have previously set up when using the focus tools manually - the idea is that it will be using a value that works for you.

The scan is best done in the same direction - that eliminates any chance of backlash affecting the results. One of the biggest problems with autofocus is if the focuser is in the backlash area when you start measuring - when that happens the focus position value changes, but the focuser is not actually moving. It's quite possible for random fluctuations to then be picked up as a 'best focus' at that point (I've seen that happen in other applications and in SharpCap, although SharpCap now applies some statistical tests to try to stop it).

cheers,

Robin
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Re: A brief introduction to the SharpCap Sequencer

#108

Post by Moorefam »

Robin,
Thanks I discovered the ability to set the number of manual focussing steps in manual just this evening.
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