What did I do?

[Shimonu]

I was out tonight trying to figure out what was wrong with my guiding. I would always have the Total RMS climb to around 2" and it could be stable for some time and fluctuate, sometimes as bad as going to 4". Most of the error would be in RA from what I could see so I was worried my mount had to much play in the RA axis and tried to tighten it and make sure I couldn't feel anything. This didn't seem to have any effect. After being out for an hour trying to run PHD2 guiding assistant among other things and failing I just started to look at what options i had in Ekos and eventually I just tried setting the binning to 2x2 thinking maybe some different stars would be chosen. Bam, suddenly my guiding is great! It'll be around 0.75" at the best and 1.5" at the absolute worst. I'm ecstatic, I feel like such a weight has been lifted and everything is falling into place!

But what about this makes a difference to guiding? What is changing by going to bin 2x2 to have the guiding improve so noticeably?

[Seelive]

5 hours ago, Shimonu said:

... But what about this makes a difference to guiding? What is changing by going to bin 2x2 to have the guiding improve so noticeably?

I assume you're binning the guide camera 2 x 2 so if the guiding software doesn't know that you've effectively doubled the size of the guide camera pixels then I guess that the reported errors would be halved.

[Shimonu]

3 hours ago, Seelive said:

I assume you're binning the guide camera 2 x 2 so if the guiding software doesn't know that you've effectively doubled the size of the guide camera pixels then I guess that the reported errors would be halved.

Well that would be a bummer... I'll post in the indi forums to see what they say.

[alacant]

13 hours ago, Shimonu said:

Ekos

Hi

Keep it simple? Perhaps best to lose phd2 and use the EKOS internal guider instead. The latest SEP multistar is excellent.

Cheers

Edited August 5, 2021 by alacant

[Shimonu]

2 hours ago, alacant said:

Hi

Keep it simple? Perhaps best to lose phd2 and use the EKOS internal guider instead. The latest SEP multistar is excellent.

Cheers

Sorry, I was a bit unclear. I was only trying to use PHD2 for the guiding assistant or other tools for diagnosing issues. I normally use the internal guider with multistar guiding.

[alacant]

16 hours ago, Shimonu said:

guiding improve so noticeably

Hi

Do your images confirm this improvement?

Cheers

[Shimonu]

48 minutes ago, alacant said:

Hi

Do your images confirm this improvement?

Cheers

Unfortunately, no. I have pretty elongated stars so it would appear the values being reported were not true. Thinking about it they were pretty much half of what I would normally see.

[alacant]

13 hours ago, Shimonu said:

elongated stars

That's a pity. 

Unfortunately there is perhaps too much emphasis placed upon screen/graph/number watching. 

In the end, to guide successfully, your mount must be as close to mechanical perfection as is humanly possible. That means dismantling, cleaning, lubricating, adjusting, replacing...New mounts too. Some would say, new mounts especially.

There's only a certain -small- amount software can do. Our initial advice remains. The idea to keep it simple would be to take all the EKOS defaults. Then examine the images.

Forget third party apps, guiding assistants and RMS values. Rebuild the mount. Then, with a base reference and logs from which to work, it becomes much easier to improve the guiding and for others to advise.

Otherwise, all we can do is guess.

Cheers

Edited August 6, 2021 by alacant