SGP will not wait on Dither completion PHD tries to recenter star


#1

In chatting with Marco we discovered we had the same issue, namely after a sub is downloaded, SGP gives dither command but starts the new image capture immediately, I have a setting that stops current frame if guidestar distance is to far so in most cases it will interrupt the sub. This repeats 2 - 3 times, and then SGP finally realises it needs to wait for the dither …
We use both D810A … Now I can’t remember seeing this with CCD camera, but I could be wrong …

Using PHD 2.6.1 and SGP 2.5.1.17 (Marco is running PHD 2.6.2 I think)

(forget log after midnight, something went wrong, never had this, W10 also updated …)
sg_log_dither.txt.zip (64.3 KB)


#2

What are the settling options configured?

Settle at < .2 pixels for 0 seconds? Maybe you can increase your settle seconds to 3 or more?


#3

That is not the issue, though it would help to counter the issue, and could be a workaround till it’s fixed.
It’s that wright after the dither command SGP fires the next sub … as if it thinks PHD is already within distance …

Could very well be a PHD issue that is not understanding the dither command, I’ll see if loging was on for PHD …

/Yves


#4

PHD log;

PHD2_GuideLog_2016-08-25_211332.txt (416.7 KB)


#5

Check out the log it says PHD2 returned .1

8/25/2016 10:20:28 PM] [DEBUG] [Sequence Thread] PHD2 distance request…
[8/25/2016 10:20:28 PM] [DEBUG] [Sequence Thread] PHD2 distance request returned 0.1…
[8/25/2016 10:20:28 PM] [DEBUG] [Sequence Thread] Distance is below 0.2, starting timer…
[8/25/2016 10:20:29 PM] [DEBUG] [Sequence Thread] PHD2 distance request…
[8/25/2016 10:20:29 PM] [DEBUG] [Sequence Thread] PHD2 distance request returned 0.1…
[8/25/2016 10:20:29 PM] [DEBUG] [Sequence Thread] Distance stayed below 0.2 for 0 seconds, done settling…
[8/25/2016 10:20:29 PM] [DEBUG] [Sequence Thread] Auto guider has settled…


#6

Yes, eventually SGP will realise that PHD is settled, but it fired already exposures before as if it was not waiting for PHD to complete the dither …
Guess both logs need to be correlated on time basis, all I can say is that I hear the shutter going off several times when it shouldn’t … and I was letting this one pass, but I’m not alone while chatting with Marco he said, hey I’ve got the exact same issue …

Thanks for looking at it,
/Yves


#7

I guess my point is PHD2 thinks it has completed the dither and reported settling has completed.

When you watch the PHD2 graph you will see a ‘dither’ command being sent when dithering is sent.

Are you noticing streaks in your images?

Either your mount is very good and it settles that quick or all you really need is to enable that delay option I have mine set for 3 seconds. But mine is for <.4 pixels, as I found that worked best for me, if I was at .2 pixels it would probably take forever to settle.

Do you have the correct focal length / pixel size of your guide scope /camera setup in PHD2 correctly?


#8

Yes I did enter correct settings in PHD and no my mount is not that fast/good …

So the funny thing is, SGP fires those shots, then it realises PHD is still settling, it then waits and it starts at the wright moment … (shots are dropt due to the setting that if PHD reports 0.5 distance the frame should be dropped )

/Yves


#9

Try setting a 4 second delay and see what happens.

Something sounds like a setup or timing is too fast. For example on my setup in the status bar of SGP it reports the autoguide settling pixels are x distance away and you can see the number getting smaller each few seconds. When it gets the pixel distance less than .4 (in my case) it then checks this for 3 seconds and then SGP triggers. It works too well.

What sort of equipment are you using.


#10

In this instance, Nikon D810A + Star 71 + AZEQ5 …
But I use other camera’s, mounts and same laptop, no issue …

/Yves


#11

Cool we have the same mount.

You are using OAG?


#12

No on anything below 1000mm I use a guidescope 250mm focal length, on my bigger mount RC yes …

/Yves


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