×

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

Bi-monthly release with minor bug fixes and improvements

Manual coarse alignment of polar mount with sync to HA/DEC instead of RA/DEC

  • Posts: 64
  • Thank you received: 9
Hi,
it would be comfortable to have the capability of a first manual coarse alignment of a polar mount using the indexes on the telescope axes. These indexes generally allow to point the telescope to south meridian with DEC=0. This implies the capability to sync to HA=0 and DEC=0. It seems to me that Ekos allows only sync with RA/DEC or AZ/ALT coordinates. So, when using RA/DEC, one needs to manually convert HA=0 to RA or when using AZ/ALT, one needs to set AZ=180 and ALT=90-latitude. Are there other alternatives to avoid these computations?
Request from a lazy astronomer :) .
3 years 7 months ago #58514

Please Log in or Create an account to join the conversation.

  • Posts: 1957
  • Thank you received: 420
Hi,
HA = RA - LST. Is that enough to get you started?

Wouter
3 years 7 months ago #58523

Please Log in or Create an account to join the conversation.

  • Posts: 554
  • Thank you received: 138
I think Fabrizio is looking for a starting alignment for the Celestron AUX driver he's working on.

AFAIK most drivers expect that a mount will already be aligned using it's HC but in any case the mount axes need to set to some initial starting position.

What I'd do is add a separate align method to the driver, after all it's not needed for most drivers.

I'd use the same alignment position that the Celestron GEMs already use, at declination 90, Ha +6h or -6h - counterweight down. This is where the index marks on the Celestron GEMs are and also where the Axis Home switches are for the high end mounts.
3 years 7 months ago #58525

Please Log in or Create an account to join the conversation.

  • Posts: 64
  • Thank you received: 9
Chris is right.

My rationale behind celestron AUX development is to have a reliable driver for remote usage. In particular, a driver with an alignment procedure completely remotable. Unfortunately, celestron AUX driver lacks an automated alignment at telescope power on that makes a match between the coordinates read from telescope motors and Ekos coordinates.

As stated by Chris, the power on alignment normally require to put the telescope in some initial position. In my case, a CPC 1100, the telescope starts with AZ=0 / ALT=0, but since I have it on an equatorial wedge that means to point it perpendicular to polar axis looking into the ground, toward north meridian.
To avoid this manual operation, I have installed a 3 axis acceleration sensor on the scope, it gives the telescope attitude with 1 or 2 degrees of uncertainty.

So, I need to add to the driver the capability of an initial "sync" doing the wanted coordinate matching.
I see two alternative ways.
1. a one time write into telescope motors the real coordinates coming from the accelerator.
2. saving the initial difference between the two coordinates and using it to correct motor coordinates each time they are read.

Any suggestion is welcome.
3 years 7 months ago #58532

Please Log in or Create an account to join the conversation.

Time to create page: 1.791 seconds