Polar Alignment via Platesolving

[Jean-Francois]

Hello nandojoe,

here a short message for saying that I tested your modified script with my EQ8 and a small telescope.
If each sky position is clear, then it works fine. But not with trees, cloud or side of the house ... the script try indefinitely to plate solve an image without stars (or too low number of stars).

I did not found the time to dig back in my script for the implementation of the modification.
I'm thinking to add a pop up message asking to decide the next action : "wait, retry or cancel" the actual sky position.

For the "alignment steps" ... it was working properly, so it was possible to adjust the mount basis without that the script crash.
My next idea is to add the visual adjustment guiding similar to SharpCap polar alignment ... select a right star and draw a direction vector.

Regards,
Jean-Francois

[nandojoe]

Hello, Francois. Please accept my apologies for the delay. I’ve gone through some professional changes, which caused me to lose focus on the script for a while.

I recently created a new script that uses a calculation methodology very similar to yours. I point my telescope toward the south, set the altitude to 8.6º (based on my latitude), and aim it at any star. The system performs a *plate solve*, selects a star, and calculates its *drift*. Based on this, the script tells me how much of an adjustment is needed (up or down, left or right).

I decided to develop this new version because it works with any star. You simply point the telescope roughly toward the celestial south, perform a plate solve to determine the camera's orientation, and wait for the system to indicate the necessary corrections based on the observed drift.

[Jean-Francois]

Hello nandojoe,

No problemo

I have too other "point of interest" in the past months.
I have a new larger telescope installed on my terrace.
And in the meantime, I rebuild my RASA8 after dismounting the corrector plate and the mirror cell.
I installed the IR Flocked velvet material in the tube and other parts of the RASA8.
I will continue with some modification of the dew shield and installed some IR Flocked in it too.

Concerning the Polar Alignment ... if you use "only" the drift method, it will work too, but it takes more time and it is still an iterative method.
Except you have like PHD2 some calculation and a visualisation of the offset. The problem is ... if you do the PHD2 drift alignment, you will remark that fist you need to wait at least 10 minutes on one position, and then the value is still varying. If you wait 2 minutes more, it will show a different offset and 2 minutes more again a different value.

Regards,
Jean-Francois

[nandojoe]

Yes... I understand perfectly. In my specific case, it performs a plate solve, stores the position of a star in its memory, and then uses that same star to calculate the drift every 2 seconds (or 3, or 4... it’s configurable).

I make an adjustment to the mount, perform another plate solve, and it continues calculating the drift until it reaches a point that is acceptable to me.

I don’t need a perfect alignment—just something acceptable. It worked very well for me. For the first time, I was able to take photos with 60-second exposures. Usually, it takes me 3 to 5 minutes to reach a minimally acceptable level.

Plate solve, adjust, plate solve, adjust...! Repeating this process 2 or 3 times is more than enough for me.