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

Bi-monthly release with minor bug fixes and improvements

Satellite confusion

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Replied by Romain Fafet on topic Satellite confusion

Thanks you for the feedback. It was the kind of problem I was expecting. Reducing the guiding duration may help but I am skeptical about the fact that it will allow a smooth tracking (do not try to reduce update_delay in the script, it wiil have no effect as pyephem has a time resolution of 1s).

It would be better to control individually RA and DEC speed but I haven't found a standard way to do that. I will add a dedicated property in the driver of my homemade mount. For other drivers I was thinking about timed pulse guide but it seems to be limited to very low speed. Do you have an idea ?
7 years 2 months ago #13413

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Replied by Andrew on topic Satellite confusion

@pauledd Thanks I found my mistake. Problem was I did not include the 1 and 2 at the beginning of the two lines.
I think that image shows great promise. If that were the ISS while recording video, I bet there would be plenty usable frames. I'd be satisfied with simply maintaining it in the FOV for that reason. Absolute precision is likely not achievable. Alternatively implement leapfrogging to a point it will soon cross, then jump ahead a bit and wait for it to pass again.

What mount did you use for this? I have an HEQ5. I'm considering satellite chasing with just a guidescope CCD on it rather than my full setup.
7 years 2 months ago #13422

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Replied by pauledd on topic Satellite confusion

HEQ5 here too. You might get into trouble with the fov. I dont know how much you want to magnify. Just one thought: the image I took was at 550mm focal length. For the ISS you will certainly use a much higher focal length (I dont know, I never tried it). But assuming that you double to 1000mm you then have a 1s guiding pulse that almost fills your fov (with sensor size 5184x3456, if you record with lesser your fov will shink even more) plus ISS is much faster than the Ariane junk that I captured

But hey, I dont want to prevent you from trying this as I really dont have any experience in that area. :P
--= human, without Windows™ =--
pls excuse my bad english! :)
Last edit: 7 years 2 months ago by pauledd.
7 years 2 months ago #13423

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Replied by Andrew on topic Satellite confusion

My telescope is 1000mm F5. FOV of 1.28° x 0.85° with Canon 600D DSLR
Guide scope 280mm F4.6 with an FOV of 58.93' x 44.2' with ASI120
Nobody said this would be easy. ;)
I have managed to capture some ISS by manually pushing the scope while trying to keep it in my finder crosshairs on the EQ mount. A task that would have been made simpler with a dob or any ALT-AZ.
Last edit: 7 years 2 months ago by Andrew.
7 years 2 months ago #13433

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Replied by Andrew on topic Satellite confusion


That sounds to me a bit like how guide rate functions. As a multiplier of some fraction of sidereal rate set and a proportional rate. Just brainstorming here, but as you say, rather than issuing a series of slew target commands; calculate and instruct the mount with differential guide rates instead. I know ASCOM is dumb, but I think it can take instructions to move RA/DEC at such and such rate until told otherwise. That might track better and also free up slew commands to manually enter corrections?
I really don't know if that's how it works or not though, but it seems logical to me. :silly:
Last edit: 7 years 2 months ago by Andrew.
7 years 2 months ago #13443

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Replied by Andrew on topic Satellite confusion

It certainly should be possible to adjust the RA and DEC slewing rates independently.
They describe such a function they call a continuous tracking state for a sattrack app used with EQ-Mod.
eq-mod.sourceforge.net/faqs/sattrack.html
Maybe if this is open source it can be ported over?
Edit: It's not open source, it's shareware.
I wonder if they would be willing to collaborate on a Linux port, as it appears to be Windows only.
At least this shows that custom slew rates + pulse guiding commands are possible for satellite tracking.
Their website: heavenscape
Their app in action: EQMODLX: Satellite Tracking
Last edit: 7 years 2 months ago by Andrew.
7 years 2 months ago #13478

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Replied by Jasem Mutlaq on topic Satellite confusion

I can see this possible with EQMod, but what about other mounts? Can there be a general solution for all mounts?
7 years 2 months ago #13483

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Replied by Andrew on topic Satellite confusion

I think their app output LX200 commands and then use EQMOD to convert it into ASCOM if necessary.
One thing to note though, I found in their forum that the MC firmware of many popular mounts such as skywatcher can't cope with rapid slew rate commands while near the zenith as it introduces a pause with each instruction at elevations somewhere above 70°
7 years 2 months ago #13493

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Replied by Andrew on topic Satellite confusion

I just made a total reinstall from scratch, and now this script gives me the error
Traceback (most recent call last): File "../Track.py" , line 21, in <module> import Py Indi
ImportError: No module named 'PyIndi'
How can I resolve this?
7 years 1 month ago #14232

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Replied by Andrew on topic Satellite confusion

Scratch that, I managed to install PyIndi. But now I get a similar error on line 25, "No module named 'ephem' ".
I installed ephem-3.7.6.0 via pip to no avail.
7 years 1 month ago #14233

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Replied by Andrew on topic Satellite confusion

I fixed my issues. So for the record if it helps others here's what I did.
1. I made double certain to follor the INDI instructions on installing Python
2. Upgraded pip3 by elevating it with sudo
sudo pip3 install --upgrade pip
3. Again with sudo, (important) installed Pyephem
sudo pip3 install pyephem
7 years 1 month ago #14302

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Replied by fehlfarbe on topic Satellite confusion


I tried the satellite tracker software some years ago with my EQ-6 mount and EQMOD. I tracked several satellites with good precision. Here you can see a video of Globalstar M030 with 8" f/5 newtonian telescope and EOS 550D:
and another video of Globalstar M003 that shows periodic flares from the satellite:


I also tried to track the ISS and some other satellites but there was the problem that tracking rates above 1000 arcsec/sec (iirc) weren't possible. If the speed changes at tracking rates above 1000 the motors stop for a short time and then start to re-accelerate. This means the mount "jumps" from position to position and doesn't catch the satellite because the ramp acceleration is too slow.
IIRC this is a "feature" of the Skywatcher motor driver to prevent damages on the stepper motors.

Maybe someone fixed this problem. Last time I tried the software was 2011 or 2012.
The following user(s) said Thank You: pauledd, Ales
Last edit: 7 years 1 month ago by fehlfarbe.
7 years 1 month ago #14315

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