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INDI Library v1.9.2 Released (14 Sep 2021)

Bimonthly Stable INDI Library release introduces new drivers and fixes for existing ones.

How does Ekos set the environment temperature?

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1 year 4 months ago #54296

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Is there a similar plan to migrate github.com/indilib/indi and github.com/indilib/indi-3rdparty to a new repository?

Thanks
Jerry
120 MM Skywatcher Esprit on Celestron CGX, ZWO ASI 224MC guiding, Pegasus FocusCube v2
Nikon Z7 8256 x 5504, 35.9 x 23.9mm 4.34 um. Triad Ultra Quad NB Filter
1) Odroid-N2 Ubuntu-mate 20.04 2) StellarMate on RPI4 8G
The good, the bad, the ugly at sciencedowneast.no-ip.ca/zenphoto/
1 year 4 months ago #54298

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No, INDI is a different project than KStars.
Jasem Mutlaq
Support INDI & Ekos; Get StellarMate Astrophotography Gadget.
How to Submit Logs when you have problems?
Add your observatory info
The following user(s) said Thank You: Jerry Black
1 year 4 months ago #54331

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FYI, a code patch was submitted yesterday to both broaden the base of captured temperature sensors for focus logging (PPB, V2, and other temperature sensors seen by the observatory tab), and also to add a dedicated autofocus log containing correlated fields for each successful autofocus. The format is a single header line + data lines as follows:

date, time, position, temperature, filter, HFR
2020-06-01, 15:06:53, 42578, 15.0, Red, 1.119
2020-06-01, 15:07:53, 42443, 15.0, Red, 1.19

Hopefully, this will be a step towards better focus control for everyone. Code is awaiting approval. cheers, Doug
RASA11, Celestron CGX-L, ASI183mc Pro, 60mm guider + ASI290mm mini, ASI EAF focuser, PPB, Rpi4-4Gb+SSD, Powered USB3 hub, hardwire Ethernet.
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1 year 3 months ago #54979

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Back to the earlier idea of temperature and elevation based focus compensation for an update. Over the last couple of months, I've used the autofocus log to map out temperature and elevation focus position dependencies for my gear. I'll note we should have added elevation to the autofocus log entries; we're going to need that (automation). The path forward to a focus position model seems fairly straight forward.

The idea is pretty simple (shown in Excel for POC). Use autofocus log to plot measured focuser positions vs temperatures with a trendline (function). The coefficients of that function define the focus temperature model. Going further, if you subtract the trend function output from each focus measurement, you create a residual. Plot the residuals set against elevations with a 2nd trendline (function), and you have the additional coefficients for the focus elevation model. Using temperature alone, or temp+el functions, a good/better starting autofocus focuser position can be determined. Longer term, more dynamic options present themselves.

Why bother? Well, as others have noted, if you don't start autofocus from a good starting position (seed), solution time can add up quickly. Worse, a bad seed could escape the solution envelope entirely. To implement this within Ekos, we don't need graphs. We could survive with off-line plot analysis + a couple of radio control buttons (enable/disable temp & el compensation separately). We'd also need fields for the function coefficients (linear + offset for each function could work, but 2nd order coeffs might be desirable for some focusers). The seed should be auto-generated/displayed. It could be enabled for auto use, or just calculated (for manual eval/entry). I attach a couple plots to show the idea. The trendline functions are shown at top/left in each plot (combined for Temp+el at top). The green line at the bottom is a simple calculator for the seed (using temp, el inputs). Long term, and for stable/well defined focuser setups, a dynamic delta el focuser update might allow for longer imaging runs between autofocus events. Comments?
RASA11, Celestron CGX-L, ASI183mc Pro, 60mm guider + ASI290mm mini, ASI EAF focuser, PPB, Rpi4-4Gb+SSD, Powered USB3 hub, hardwire Ethernet.
Last edit: 1 year 3 weeks ago by Doug S.
1 year 3 weeks ago #59127
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This looks very interesting, but I must confess I'm out of my league here. I have questions...
What is the logic/purpose behind elevation being added to the relation?
Where is the autofocus log file you referred to in the previous post and can how can it be viewed? [ I see the logs are in ~/.local/share/kstars/focuslogs].

  • Now that autofocus might be working for me, with help from a friend and Hy, I'll pay attention to these.

    Thanks
    120 MM Skywatcher Esprit on Celestron CGX, ZWO ASI 224MC guiding, Pegasus FocusCube v2
    Nikon Z7 8256 x 5504, 35.9 x 23.9mm 4.34 um. Triad Ultra Quad NB Filter
    1) Odroid-N2 Ubuntu-mate 20.04 2) StellarMate on RPI4 8G
    The good, the bad, the ugly at sciencedowneast.no-ip.ca/zenphoto/
    Last edit: 1 year 3 weeks ago by Jerry Black.
    1 year 3 weeks ago #59164

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    @Jerry: Re: "What is the logic/purpose behind elevation being added to the relation?"

    Changing airmass is the easiest rationale to visualize why Elevation correlates to focus. Many scientific observatories employ temperature and elevation focus compensation of some kind or another (so I had a good hint it would be a factor; just didn't know how big for my tel/focuser setup). As you can see in my prior posted el graph (to be confirmed with more data), I expect to adjust ~8 counts per degree of el change. If you plot your temp residuals to el data and see a slope you believe is real (not just fit to noise), with a magnitude that gives you pause, you'll likely become a believer in the need for autofocus seeds and possibly dynamic delta based updates too. ;-). Cheers, Doug

    edit: I might add that because the change in airmass isn't linear (especially at low el), I would expect to need a non-linear function (quadratic or cubic) once low el data begins to fill in. The only argument against this is that folks shouldn't be taking photos at low elevation! Hard to avoid it sometimes though (south targets in north latitudes, and vis-versa). This is why I suggested that coefficients might want to support 2nd or 3rd order terms.
    RASA11, Celestron CGX-L, ASI183mc Pro, 60mm guider + ASI290mm mini, ASI EAF focuser, PPB, Rpi4-4Gb+SSD, Powered USB3 hub, hardwire Ethernet.
    Last edit: 1 year 3 weeks ago by Doug S. Reason: clarification
    1 year 3 weeks ago #59169

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