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

Bi-monthly release with minor bug fixes and improvements

Custom Tracking Rate

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  • Thank you received: 7

Custom Tracking Rate was created by Lars

Sorry if I ask this question again, but I asked it the Astroberry section and haven't got any answer. I think it's better to ask about it here in the Mount section. And I have more information now. The problem I have is that I'm trying to take photos of the comet C/2022 E3 ZTF and now in January/February it's moving fast. I want to take many longer exposures and need to have the mount track with a Custom Tracking Rate.

First, from the CdC I get the comet's relative speed:



But it's in hour and I need arcsec/sec for INDI EQMOD driver. On my homepage I have done a angle format calculator:

www.astrofriend.eu/astronomy/astronomy-c...gle-conversions.html



Which deliver this setting for the comet's speed in arcsec/sec at January 31st which I think is correct calculated.



I get a warning and it say that the dDEC to 0.01 x sideral (15), that's is 0.15 arcsec/sec. According to the limits, 0.05 to 800 x sidereal ( 0.05x15= 0.75 and 800 x 15 = 12000 ) so of course it's out of range.

Still I have put in a really high relative speed of the comet. With these range limitations it's impossible to correct for comet's relative speed. Isn't the Custom Track Rate meant to this purpose, to follow comets and asteroids ?

To me it looks that INDI shouldn't multiply the limits ( 0.05 to 800 ) with the sidereal rate (15) to get this to working. Or am I wrong ?

More realistic have been a range of:
dRA, from 15.04 +/- 0.01 arcsec/sec to 15.04 +/-800 arcsec/sec.
dDEC, from +/- 0.01 arcsec/sec to +/-800 arcsec/sec.

Or does it need to be a lower limit, 0.01 could be 0 also, only a maximum limit.

1' / hour is 0.017 arsec/sec. When making a movie the comet can be followed for many hours.

/Lars
Last edit: 1 year 2 months ago by Lars.
1 year 2 months ago #89666
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  • Posts: 145
  • Thank you received: 7

Replied by Lars on topic Custom Tracking Rate

I think I have solved the problem now. The lower limit for Custom Tracking use the same limit as for SlewTo functions. The lower limit was too high and the lower limit doesn't need to be there at all. I erased it and only kept the higher limit. Did this both for RA and DEC.

It's in the Indi file skywatcher.cpp

void Skywatcher::SetRARate(double rate)
{
double absrate = fabs(rate);
uint32_t period = 0;
bool useHighspeed = false;
SkywatcherAxisStatus newstatus;

LOGF_DEBUG("%s() : rate = %g", __FUNCTION__, rate);

// if ((absrate < get_min_rate()) || (absrate > get_max_rate()))
if ((absrate > get_max_rate())) // This is the new limit, only the higher left

With a lot of help from a friend I succeeded to compile it. Now I put in very small dRA and dDEC speeds, use it for hunting comets. Now when I know how to compile files I can correct other things too. Next problem to solve is how to hande Custom Gear Ratio which I have in my EQ6 mount. It's in the same file.

/Lars
The following user(s) said Thank You: Alfred
1 year 1 month ago #90034

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