×

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

Bi-monthly release with minor bug fixes and improvements

Using the Ekos guiding module

  • Posts: 27
  • Thank you received: 0
Wouter. I updated my profile to show equipment.

To polar align I used the PA module in Ekos. Is this a good way to get accurate PA? It was a little windy last night maybe that was a factor too?
Equipment: Skywatcher HEQ5 - Stellarvue 80mm access - Canon 6D (unmodified) - Stellarvue 50mm Guide Scope - ZWO ASI290MM Mini - Rasp Pi4
4 years 1 week ago #50820

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

  • Posts: 1957
  • Thank you received: 420
Wind may affect polar alignment yes. And the best way to get good polar alignment is to make sure that the pink line starts on a star selected by you as well as possible and that your selected star ends up on the other side as well as possible. Possibly repeat once or twice to verify that all went well. And use the zoom capabilities of the image viewer to make sure that the star is as close to the center of the end of the pink line as can be. I have reached polar alignment of less than 1 arc minute with my HEQ5 using an ASI1600MM and an F=400 mm telescope.
4 years 1 week ago #50821

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

  • Posts: 27
  • Thank you received: 0
One thing that is very frustrating for me when doing the PA is that the image doesn't update to see the new star position relative to the pink line till every other capture. For example, I will guess the adjustment, it will take the image but the star stays in the same position until the NEXT image. Does this happen to you? It really slows the whole process down.
Equipment: Skywatcher HEQ5 - Stellarvue 80mm access - Canon 6D (unmodified) - Stellarvue 50mm Guide Scope - ZWO ASI290MM Mini - Rasp Pi4
Last edit: 4 years 1 week ago by Martin.
4 years 1 week ago #50824

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

  • Posts: 1957
  • Thank you received: 420
Yes that happens to me too and this is normal. Ekos doesn't know when you are making adjustments to the alignment of your mount so it keeps on shooting pics and displaying them. If you need to do a big correction then it helps to start with small ones first to know what direction the mount moves in when you turn a certain knob. Once you know that, you can make bigger steps to speed up the alignment procedure. Don't overdo it because you might lose track of your star which means that you probably need to start all over again.

Anyway, we are deviating from your original topic, which was guiding. Perhaps you should open a new topic if you have more questions about polar alignment.
4 years 1 week ago #50826

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

  • Posts: 27
  • Thank you received: 0
I agree on getting off track. Tonight is clear out. I'll try the things suggested so far and report back.
Equipment: Skywatcher HEQ5 - Stellarvue 80mm access - Canon 6D (unmodified) - Stellarvue 50mm Guide Scope - ZWO ASI290MM Mini - Rasp Pi4
4 years 1 week ago #50827

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

  • Posts: 27
  • Thank you received: 0
This is a screen shot of last nights imaging. The graph looks very different than the first one. Only significant thing that I changed was to switch from primary scope to guide scope. My PA was probably better too. The RMS was still up around 1.00. Sometimes it would drop to .75 other times it went as high as 1.30. I could manage 5 min subs with stars that were still round so I can't complain about that.

Equipment: Skywatcher HEQ5 - Stellarvue 80mm access - Canon 6D (unmodified) - Stellarvue 50mm Guide Scope - ZWO ASI290MM Mini - Rasp Pi4
4 years 1 week ago #50850
Attachments:

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

  • Posts: 1957
  • Thank you received: 420
As long as the RMS is lower than the resolution of your imaging camera + telescope then all is fine. I noticed that *SLIGHTLY* defocusing the guide cam works even better. Otherwise it all looks fine to me.
4 years 1 week ago #50854

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

  • Posts: 398
  • Thank you received: 117
Agree that this performance isn't bad. Again, if you want to be picky, the differential between RA & DEC could cause you to investigate and tweak a bit on an exploratory level. Is balance just right (ever so slightly east heavy)? Have you adjusted the 0.5 guide rate to see if you can balance guide aggressiveness against the limit of "chasing the seeing"? I'd experiment with parameters just a bit to see if you can get a more balanced RA to DEC RMS. In the end, these being unbalanced should show up in eccentricity for longer subs.
4 years 1 week ago #50856

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

  • Posts: 59
  • Thank you received: 3
One thing I've found that helps when adjusting the mount during PA is to make the adjustments *while* the exposure is being taken. That results in nice star trails in the exact vector of the adjustment. It makes it easy to see how large of an adjustment you just made and keep track of the star you are trying to center.
4 years 1 week ago #50865

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

  • Posts: 106
  • Thank you received: 11
Bringing your exposure down to 1sec could help. Add a dark frame also. This may allow you to then bring down the minimum correction pulse length. You can guide using quite faint stars. I can get 0.6-0.7 all night long on a still night.
Skywatcher 190MN - EQ6 Pro (with Belt Mod) - ASI1600MM-Cooled - ASI EFW7 - ASI120MM - WO f4 Guide Scope - Rigel nStep - KStars/Ekos - KDE - PixInsight
4 years 5 days ago #51027

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

  • Posts: 1957
  • Thank you received: 420
Adding a dark frame indeed will help a lot, if only to get rid of hot pixel so Ekos will not try to guide on them. But be careful with too short exposure times. The seeing usually acts on a timescale of about a second to 1.5 seconds and with a too short exposure time you may end of what is referred to as "chasing the seeing". In other words, you will be over correcting and guiding will be off. I'd advise to stick with 2 seconds at least. As a matter of fact, for me 2 seconds works better than 4 seconds. Not sure why though.


Wouter
4 years 5 days ago #51037

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

Time to create page: 0.819 seconds