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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Internal Guider not calibrating

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I use HEQ5 Pro with EQDIR-BT dongle with PHD2 and have recently made some changes to EQMod driver for this purpose. The original code didn't take into account communication delay with the mount which is around 50ms per command when using BT and around 16ms when using EQDIR cable and 32ms when using PC Direct mode via the hand controller. This made each pulse essentially that much longer. Also the code used timer for all pulse lengths which made short pulses quite unreliable. Last issue was that if mount status query timer happened to hit during the pulse duration, the pulse got significantly longer as command to end the pulse got delayed. These issues should be remedied by current EQMod driver version from nightly which added configuration items to ignore very short pulses and configurable limit how long pulses are handled synchronously. The value for minimum pulse should be around the communication delay so 50 ms for BT, less for wired connection, the default value of 10 ms is very conservative. Default value for timer threshold (100 ms) is probably good as is, but I've used slightly longer 150 ms as the limit myself.

As for the guide rate I've settled on 0.5x after testing 0.3x, 0.75x and 1x, it seems to be a good compromise between correction speed and not over correcting. I'm not sure what you mean by minimum pulse rate, I use 3s exposures so PHD2 does corrections only every 3s to average out effects of seeing. Sometimes I use 2s or even 1s, but 3s has proved to be good compromise.
The following user(s) said Thank You: Jasem Mutlaq, Jean-Luc, Petar Milevski, Helge, Tom
5 years 10 months ago #26191

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I tested with Jarno's changes yesterday and everything worked fine. Of course, I didn't have issues before (using EQDir cable, so latency wasn't much of an issue), but the results are great nonetheless!

5 years 10 months ago #26193
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Dear Jarno,

I was fascinated reading about the enhancements you made. Great job!!!

I erroneously wrote minimum pulse rate, should just have been minimum pulse (length).

Best, Helge
5 years 10 months ago #26196

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Cool, so if there is a fix for BT latency issues and its in GIT (i assume for more testing), how soon will EQMod update be in the stable release?
5 years 10 months ago #26198

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Replied by Tom on topic Internal Guider not calibrating

Is this means that the Ekos & PHD2 dithering issue is solved?
5 years 10 months ago #26201

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Unfortunately this doesn't have any direct impact on dithering with PHD2 as such, only that the dither pulses would be more accurate than before. For me dithering seems to usually work, though at times Ekos doesn't seem to register settling signal after dither, but resumes after timeout anyway. More rarely PHD2 doesn't seem to receive the dither command from Ekos at all so there seems to be some fragility with the communication between the two.
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5 years 10 months ago #26213

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Replied by Tom on topic Internal Guider not calibrating

But before the new release of Kstars, both EKOS and PHD2 works fine in dithering. Now no more. :(
5 years 10 months ago #26216

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I don't think it has ever worked better for me than it does now (which isn't perfect but usually enough), it was much worse before Robert's changes some time ago and I've used PHD2 with Ekos for about two years now. Anyway, it would be nice to figure out the issue and fix it for sure :)
5 years 10 months ago #26217

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Hi everyone,

in the meantime, I got the calibration process completing and autoguiding is up and running. However, the RMS looks poor, around "10". Maybe this is due to mechanical reasons, the telescope has a high imbalance on the DEC axis, as the telescope is heavy on that side, where the ccd is attached (I need to resolve),

Something went wrong with the csv file creation, so I guess that may not help. Could someone kindly have a look at the log file, to see if there are any errors that could contribute to the high RMS?

(the guide cam is off axis, and I am guiding via the EqMod, not ST4)

Thanks a lot in advance, Helge
5 years 9 months ago #26703
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To add this question, how does the box size impact calibration and guiding. Should the box just encompass the guide star? Somewhere I read that a large box reduces the risk of losing the guide star.
5 years 9 months ago #26708

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What did you set your minimum pulse to?!!! The autoguide is not sending any corrections and the only way this can happen (that I know of) is if you set the minimum pulse (100ms) to a high value!
5 years 9 months ago #26720

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As always, your diagnosis is spot on. It was still at 2000ms, going back to testing some weeks ago!
5 years 9 months ago #26723

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