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INDI Library v1.8.1 Released (09 Sep 2019)

Monthly maintenance release INDI v1.8.1

Preemptive corrections on tracking speed based on astrometric solution

2 months 2 weeks ago
elakrab
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Preemptive corrections on tracking speed based on astrometric solution #42741
While yesterday fighting with the drift of my mount I got this idea

In cases like mine, the main issue with astrophoto is not really the periodic error, but the non perfect polar alignment, particularly since I don't have access to the polar star region and I am not so sure I want to waste time doing slow iterative methods like drift alignment or DARV.

However, just correcting the order 0, linear, drift (hence ignoring completely field rotation within subs) might be enough for my application. I could imagine something like astrometry running in the background for the last couple of pictures, estimate the drift and distribute guiding pulses or az/dec corrections within the next exposure so that we have some kind of fake guiding to correct such drift in small steps. Would it be doable?

Set 1 -> AZ GTi, redcat51+Canon 6D, guide: 30mm+ZWO ASI 120MM.
Set 2 -> Star Adventurer, lenses+Canon 6D
Set 3 -> NEQ6, LX90-8' OTA/MN150 + 450D peltier, guide: 50mm+QHY5.

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1 month 3 weeks ago
james_lan
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Preemptive corrections on tracking speed based on astrometric solution #43975
I have thought about it before, and I really think it's a good idea to look at.

Especially If it's obtained over a time period, if there was a way to pass a value for how fast/slow it's moving (assuming RA only) then that could allow for some drivers to adjust their tracking rate to correct. (I know OnStep could, and I suspect others.)

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1 month 2 weeks ago
elakrab
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Preemptive corrections on tracking speed based on astrometric solution #43979
Or even, more refined and cool, if we know how the stars trail, estimate the polar alignment error and just adjust the tracking speed in both axes to compensate it, so only the field rotation remains. For short focal lengths I think it will remove the need for a super accurate polar alignment or guiding

Set 1 -> AZ GTi, redcat51+Canon 6D, guide: 30mm+ZWO ASI 120MM.
Set 2 -> Star Adventurer, lenses+Canon 6D
Set 3 -> NEQ6, LX90-8' OTA/MN150 + 450D peltier, guide: 50mm+QHY5.

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1 month 2 weeks ago
Ihoujin
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Preemptive corrections on tracking speed based on astrometric solution #44053
Seems a bit convoluted and prone to add additional tracking error.
Perhaps alternative polar alignment strategies could be developed. Such as with celestron mounts that are capable of determining alignment error with a couple align points then slewing a away a little by the amount required to correct it with the latitude and azimuth bolts.

INDI/KStars on Raspberry Pi 3B+
Lubuntu 16.04
Skywatcher HEQ5 Pro Mount
Canon 600D Camera
Orion SSAG @280mm Guide Scope
PHD2
Adafruit Motor Hat shield
Adafruit GPS Module
Generic Bluetooth Joystick.
Startech 7 port powered USB Hub.

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