Sequence Planner questions.

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rockenrock
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Sequence Planner questions.

#1

Post by rockenrock »

Hi Robin,
I have been editing a sequence with sequence editor.
1. How do I get back to Deep Sky Sequence Planner main screen?...
I saved my sequence after editing it and closed the editor (X in top right corner). My camera is connected. I disconnected and then reconnected it in SharpCap menu. But Sequence Planner is greyed out inside the main menu Sequence Planner. The Edit button is available.

2. I am using PHD2, and familiar with how it works. Before SharpCap I dithered with PHD2 via the mount. I am new to SharpCap (1 month). I and want to dither after each time I save a live stack of 30 frames, not after a time period. Is this using the Request a single dither from Guiding Application? Or is it in the Sequence Planner I cannot get to open in my first question?

I know I need to go back to think about the 4 sections of Sequence Planner.. Before Capture, Capture List, After Capture Complete, and Action Buttons.

So far I really like the Sequence Editor, and it has done everything I set it to do. Thanks!

Roger
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Re: Sequence Planner questions.

#2

Post by admin »

Hi Roger,

you need to actually have the camera open in SharpCap for the 'Deep Sky Sequence Planner' to become available - this is because the deep sky planner customizes the options it shows you based on the capabilities of your camera (and of the other hardware that you have connected). It will therefore allow you to produce a plan that is valid for the currently open camera, giving you cooling options if you use it when your cooled camera is open but not if you use it when an uncooled camera is open, etc.

The main sequence editor doesn't have this restriction (in fact it has steps to allow you to open and close cameras if you want), but it gives you much less assistance - you need to know what you are doing or be prepared to do some trial and error. You can go (one way) from the planner to the full editor to make more tweaks, but you cannot take the additional tweaks you have made back into the planner.

If you want to do live stacking, then the main sequence editor is the one you want - the deep sky planner does not set up runs of live stacking for you.

If you do set up a sequence to do live stacking in the main editor then you can do dithering in two ways

1) Set up the dithering options in the live stacking UI during a manual run of live stacking, then you are done. The live stacking runs that are set off by the sequencer will use these settings. This might be hard to arrange for the setup you want of a single dither after each stack though.

2) Set the dithering options to off in the live stacking UI and use the 'request a single dither' step in your sequence. Remember to include a 'Monitor guiding application' step and a 'Start guiding if necessary' step near the start of your sequence otherwise the 'request single dither' step will not work.

Hope this helps,

Robin
rockenrock
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Re: Sequence Planner questions.

#3

Post by rockenrock »

Hi Robin,
I have been working on the sequence that will dither. Other than dithering my sequence works nicely. It does not dither. Before running the sequence I had PHD guiding, and PHD was connected to SharpCap. I could move the mount with the arrow keys from SharpCap. I know dithering by time works.

Now per below I will to give this up and go with dithering by time frame, debayer, calibrate and align during livestacking. This is what you advised me from the beginning.

I have been wanting to dither after groups of 30 (for example) subs that were live stacked. No alignment because I was doing without debayering. I thought this would be the best method to lead into Naturalize Scale Gradient script. But after asking on the backyardastro website forum for NSG script, John Murphy replied it is best to calibrate and align the subs during live stacking. Here is what he wrote:
+++++++++++++++++
Hi Roger,

About Sharpcap live-stacking:

1. The live-stack will align frames before saving a substack or full stack, so debayer and registration is kind of built in.

2. Since there will be micro-movements between subs while live stacking, and then registration, the final stack will not be a pixel to pixel match to any one sub (except maybe the reference). So calibration after the livestacking will not have the pixel to pixel mapping needed. It will have to be done while livestacking - this is actually built in into Livestack, but you do have to take the calibration frames before starting.

++++++++++++++++++
I think John's above advice applies to me and many others who are discovering SharpCap for improving their DSO imaging quality, and want to take advantage of the powerful NSG script. I hope you and John cooperate and bring to us imagers the best way to collect our data for best processing with NSG script and Pixinsight. I am referring to DSO objects.

I guess I did not ask a question, but I appreciate your comments where you see fit to do.

Thanks,
Roger
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Re: Sequence Planner questions.

#4

Post by admin »

Hi Roger,

thanks for the explanation of what you are trying to achieve. I have quickly read through the description of the NSG script and how it works, and I think I am beginning to follow what it is doing. I will need to give it some more thought as it may be that this is one of those features that is less well suited to the live stacking approach in SharpCap (SharpCap live stacking only looks at one frame at a time, adding each new frame to the stack without considering any previous frames in detail - this limits what processing can be done - for instance a median stacking option is basically not possible when using the SharpCap approach, but can be done in a traditional stacking application).

There is also a question of focus here - live stacking is designed to achieve decent results as easily as possible. If you want the absolute best ever stacked image then you are in the end always going to choose a dedicated stacking application like PI or DSS - perhaps by capturing in live stacking and also saving the raw frames or perhaps by a more traditional deep sky approach.

cheers,

Robin
rockenrock
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Re: Sequence Planner questions.

#5

Post by rockenrock »

Hi Robin,
Regarding stacking, in PixInsight's Star Alignment a reference frame is picked and then each sub is aligned to it. Prior to this alignment each sub is calibrated with flats, flat darks, darks and then debayered. So it sounds like there is no conflict with SharpCap which calibrates, debayers, and also uses a single frame for alignment.

I was asking John Murphy if live stacking, without aligning was okay. He says better to align (but calibrate and debayer first). I get the impression he thinks SharpCap is good for this. Now I want to do it.

I got onto this whole subject when I read about Diffraction Limit's SBIG new line of CMOS cameras that have their StackPro, live stacking in the camera before downloading system. They are way out of my price range. They mentioned improved bit depth, and less computer storage needed vs many, many short exposures. All the same things you know about.

So I want StackPro and my color camera to be my poor man's, almost as good as their over $5k, less pixels, mono camera. This blog article is a good read: https://diffractionlimited.com/more-bit ... g-feature/
Roger
rockenrock
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Re: Sequence Planner questions.

#6

Post by rockenrock »

Robin,
I think SharpCap is better than in-camera stacking because SharpCap can apply your Brightness Filter to the sub-exposures and discard any bad ones. Thus not wasting all the sub-exposures if a cloud goes by. This is a very powerful feature you have developed. Thank you!
Roger
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Re: Sequence Planner questions.

#7

Post by admin »

Hi Roger,

sounds like you are getting good advice from John Murphy - it is essential to align when stacking otherwise you suffer from all the problems of tracking/drift/etc that beset very long exposures. If you are aligning then you have to do flat/dark correction *before* aligning the frames, since they cannot work properly after the alignment has been done.

SharpCap necessarily chooses the first frame as the reference frame (whereas PI may well choose the 'best' in some way).

I am always suspicious of attempts to bundle everything into a single device (for instance the Unistellar all in one scope/imaging system or, by the sounds of it, the stacking cameras). If something goes wrong with one part then you have an expensive piece of kit that doesn't work at all. You also have limited (or no) upgrade paths. These will appeal to some who want to just take something out of the box and have it all work, but you pay a big premium for that and also have to accept the limitations that come with the all-in-one approach. Not for me ;)

cheers,

Robin
rockenrock
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Re: Sequence Planner questions.

#8

Post by rockenrock »

Hi Robin,
I am sorry, but I misread John's post. Any registration/alignment then stacking will cause problems in PI's noise evaluation, and then impair NSG script application.

I think this is an important point and I apologize for me previous message being incorrect. Let me copy my clarification question to John and his clear response....
+++++++++++++++++++++++
Hi John,
Thanks for your reply. Regarding your reply, just to clarify for me, which choice below is best for NSG script processing?

In SharpCap the software has 2 main choices for live stack:
1.) Calibrate, debayer, align, stack repeated X times, then download.
2.) Do not calibrate, do not debayer, do not align, stack repeated X times then download.

I think for my Option 2, no alignment needed in a live stack of 20x30 subs because it is no different (alignment wise) than 1 x 600s sub. So it seems to me alignment not needed in SharpCap for any person's reasonable mount/scope/guiding that can make a 600s sub with good tracking.
+++++++++++++++++++++++++++
John's reply:
Option (1) would cause significant errors in PixInsight's noise evaluation, which would lead to inaccurate weights. This is due to the registration, which smears the noise by a random amount. This has a very significant affect on the noise estimates.

Option (2) would not cause any problems.

Regards, John Murphy
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Re: Sequence Planner questions.

#9

Post by admin »

Ah, OK

In my opinion, the best answer in that case if you want to use the noise processing in PI is to not use stacking at all in SharpCap -stacking without alignment will only make *worse* final output images than could be achieved if you saved all the individual frames and sent them all to PixInsight.

What you can do is take a hybrid approach - use live stacking in SharpCap to get the 'real time' image available to view on screen, but set the 'Raw Frame Saving' option in live stacking to save the individual frames too - these raw frames from live stacking have *no* processing done to them (even if you have alignment, darks, flats, etc turned on in SharpCap) so they are perfectly suitable for processing in another application like PI.

Hope this helps,

Robin
rockenrock
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Re: Sequence Planner questions.

#10

Post by rockenrock »

admin wrote: Mon Jun 20, 2022 2:17 pm Hi Roger,

If you do set up a sequence to do live stacking in the main editor then you can do dithering in two ways

1) Set up the dithering options in the live stacking UI during a manual run of live stacking, then you are done. The live stacking runs that are set off by the sequencer will use these settings. This might be hard to arrange for the setup you want of a single dither after each stack though.

2) Set the dithering options to off in the live stacking UI and use the 'request a single dither' step in your sequence. Remember to include a 'Monitor guiding application' step and a 'Start guiding if necessary' step near the start of your sequence otherwise the 'request single dither' step will not work.

Hope this helps,

Robin
Hi Robin,
I am working on option 2 dithering above. My imaging camera and mount are connected in SharpCap. LiveStacking working well.

I edited a sequence to try out doing dithering after live stack. Sequencer monitors the guiding application (PHD2), and reports it is guiding. The entire script works, except the dithering.
Sequence editor reports: 'Dithering at a fixed period via the sequencer cannot be used while Live Stacking'.
Please look at my attached Word file with my sequence and the progress report log.

My logic is that it live stacks 5 subs of 5 seconds and saves the live stack file. I think live stacking stops just before it saves the file. Then dithers, waits 30 seconds. Then repeats this 5 times.

I cannot find the 'request single dither' step you wrote.

Anything obviously wrong and any suggestions for me to try?

Thanks,
Roger
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Live Stack sequence with dither.doc
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