×

INDI Library v1.9.2 Released (14 Sep 2021)

Bimonthly Stable INDI Library release introduces new drivers and fixes for existing ones.

Inconsistent polar alignment results

Here are the results:

 

Except for the first two, the rest were quite consistent within tolerance. The AZ/AL error would of course be different depending on where are you looking in the sky. These are all done with primary scope (Orion EON 120mm) on QHY268M Pro.
Jasem Mutlaq
Support INDI & Ekos; Get StellarMate Astrophotography Gadget.
How to Submit Logs when you have problems?
Add your observatory info
3 months 15 hours ago #73872
Attachments:

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

  • Posts: 18
  • Thank you received: 0
Hi Jaseem,

Thanks for running these experiments. OK, it's good to know the procedure itself works. Then I guess I am doing something wrong.

Paul
3 months 15 hours ago #73875

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

  • Posts: 365
  • Thank you received: 109
Well, I think it would be more accurate to say that from the data Jasem took, the procedure's variability isn't too bad (but 2 arcmins variability seems a bit higher than what is desired considering we're platesolving a solution IMO). Jasem didn't provide an output value comparison to PHD2's drift alignment output value. This or another vetted drift align output value is needed for comparison before you can say the software "works".   Consistency doesn't necessarily imply precision, and result precision is the goal so you know when good enough PA occurs.

Edit:   something just caught my eye in  Jasem's data.   All the tests were done starting on Polaris park position?  That's good for the OP test, but what about away from Polaris (say 60 degrees or lower DEC?).   This is where I experienced problems.   Jasem, could you possibly do another set away from Polaris and if possible include a drift align output value from PHD2 for comparison?  That would be very helpful....
RASA11, Celestron CGX-L, ASI183mc Pro, 60mm guider + ASI290mm mini, ASI EAF focuser, PPB, Rpi4-4Gb+SSD, Powered USB3 hub, hardwire Ethernet.
Last edit: 3 months 14 hours ago by Doug S.
3 months 14 hours ago #73878

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

  • Posts: 5
  • Thank you received: 1

Like magic! I set the FL to 120mm ignoring the warning message in Ekos and was able to get similar PA error both in Ekos PA and PHD2 drift alignment.

The routine I followed was to first run PHD2 drift alignment and guide assistant first, which reported an error of 6’5”.

Then I run Ekos PA and before adjusting the knobs it reported an error of 4’5”, a bit of a gap but much better than my previous tries.

Then I adjusted to 0’5” in Ekos and run a second iteration which confirmed the same error practically. I then run PHD2 guiding assistant and got 1’5” error.

So in my case there is something like 1-2 arcminutes of deviation between both, for me enough to use the much faster Ekos PA routine. I was able to confirm it by taking some 5mins pictures with perfect round stars.

So in my case it seems the wrong FL was the error, I hope this helps others.
The following user(s) said Thank You: Jasem Mutlaq
Last edit: 2 months 4 weeks ago by kobu.
2 months 4 weeks ago #73905

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

  • Posts: 18
  • Thank you received: 0
Still struggling with this one.
I am using the skyguider pro. Should I turn tracking _off_ while I am doing the procedure ?

I want to try the PHD2 Drift alignment as suggested by others, but my visibility on the sky is limited by buildings. E.g. I cannot see the intersection of the meridian and the celestial equator on the south side. Does this matter ? Can I still try it out regardless ?
1 month 3 weeks ago #74988

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

  • Posts: 1147
  • Thank you received: 203
Keep it on.
INDI/KStars on Raspberry Pi 4, 4gb
Raspbian Buster with AstroPi3 script configuration
Skywatcher HEQ5 Pro Mount
Canon 600D Camera
Orion SSAG/ASI120mm @280mm Guide Scope
PHD2
Waveshare Stepper Motor Board - DIY Focuser
Adafruit GPS Module
Generic Bluetooth Joystick.
Startech 7 port powered USB Hub.
1 month 3 weeks ago #75033

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

  • Posts: 18
  • Thank you received: 0
@Kobu, That's an interesting hypothesis. I will try that out myself.
How did you come to this conclusion? And 120mm ?
Last edit: 1 month 3 weeks ago by Paul.
1 month 3 weeks ago #75034

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

  • Posts: 18
  • Thank you received: 0
Just wanted to share I found the cause. The skyguider pro was not entirely stable when doing PAA. I fixed this and now the results are much better. however, still some minor variation between consecutive runs.
1 month 2 weeks ago #75338

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

  • Posts: 5
  • Thank you received: 1

That was my issue in the end as well, the position of the guide tube was not ideal, I changed it from the finder shoe to under the dovetail and this gave me the best results confirmed by PHD2 guiding assistant.

Still minor variation between consecutive runs as well, in the few arc minutes though (<5) and mostly on the RA axe, I think that is due to other factors that probably change from one run to another like wind, flexures, gear meshing, etc.

In any case this is now totally usable and will finally take me away from the looong PHD2 drift alignment method I was using until now.


Enviado desde mi iPhone utilizando Tapatalk
1 month 2 weeks ago #75343

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

Time to create page: 0.910 seconds