Auto Guider Is Settling After Each Exposure


#1

After every exposure I get the message “Auto Guider Is Settling” and then “Waiting for Guider to Report It Is Done Settling”. Is this normal or should it only be settling after a Dither? I’m using an AP1100 mount.

Should I turn this off?


#2

Perfectly normal and not a bad idea especially if dithering.

If it is taking too long just widen the tolerance a little say 4 pixels for 10 seconds or some such.


#3

If I remember from your CN thread about this, you are using very short exposures and getting lots of them. Instead of dithering every frame you could dither ever 10 frames and that way the settling wouldn’t be triggered after every exposure, and with lots of exposures you don’t need to dither as often.

Also, I think your tolerance is too tight and it may take a while for the mount to settle below your parameters. Without knowing your image scale it is hard to tell you what parameters to use, but I do think that settling for 10 seconds is a long time. That means your guider has to be within x pixels of the target for a full 10 seconds before it will resume the next exposure.

What is your image scale and what exposure length do you use for your guide camera?


#4

Not to sound upset here - but for the 10th time I AM NOT DITHERING EVERY FRAME

The issue is that the camera is settling after EVERY FRAME - DITHERING OR NOT. Should SGP be waiting for the guider to settle after each sub - dithered or not?

I am using a good mount AP1100GTO and have no issue getting the guider to settle at <2.0 for 4 sec. The issue is do I have to have this happen for every frame - dithered or not??

Again - the issue is the damn thing goes through a settling after every exposure - dithered or not!!!

I can’t be any clearer.

So, is this normal behavior for SGP - to settle after every frame - dithered or not?? or is there something amiss??

Is this a PHD2 issue?


#5

OK, sorry I didn’t get what you are after here. In my defense, you didn’t say any of this, at ALL, in your original post on this thread/forum. So how are we to know? I vaguely remembered you posting about this on CN but obviously don’t remember the details of that.

I can’t answer for sure, but it seems to me that this is not expected behavior. If you are not dithering at all or not on every frame then I would certainly not expect the mount to be settling in any way after the exposure. It should just move on right away to the next exposure.

I have mine set up to dither after every 3 exposures. I think it will be clear tonight and I’ll try to pay attention to what happens after a non-dithered frame, but again I’m pretty sure it just goes right to the next exposure.

Just for my own curiosity, can you post a screenshot of your Control Panel/Auto Guide tab with the settings you have set up? And are you rotating filters between every exposure, or completing all exposures on one filter before moving to a different filter?


#6

Hi,

Thanks. But my title did say “each exposure”.

Don’t get me wrong though, I truly appreciate the help as I would be lost without it.

That’s also what I was hoping for - no settling unless a dither was called for.

I usually complete the entire event first before moving on to the next. I am only using Lum currently.

Again Thanks


#7

Yeah, I see no reason why this should be happening. Are the messages in the lower left (“waiting for autoguider to settle”) just flashing by, or does this take a several seconds before the next exposure starts? I’m just trying to get a feel for how much this is affecting the total time (is this just a display issue or is the mount actually settling for several seconds).


#8

Yes, they are in the bottom left and they aren’t flashing by. By the time it actually begins another exposure I’d say its between 5 - 10 secs.

When I was doing the 5sec exposures I was only getting 3 or 4 frames for each minute because of the settling thing.


#9

OK I’m really not sure what’s going on. Again, I’ll try to watch things tonight and see how it behaves in my setup. It would probably be helpful if you could run a short sequence where this happens and post the log file (or maybe you have already in a different thread?).


#10

I think I may have the log file from the other night. But I will do one tonight - wx permitting - and post it.

Thanks


#11

Here is a quick log where I ran 10 exposures with a dither at frame 11 (so no dither called for). Eac one showed it was settling.

sg_logfile_20170830213853.txt (323.5 KB)

Hope I uploaded it correctly


#12

I don’t see anywhere to tell it not to settle after every frame. It’s never been a problem for me because I do 20-30 minute exposures. I have however just turned it off on occasion by unchecking the box or when seeing is bad by reducing the time by changing how long I want it to settle for. If you are shooting multiple frames why don’t you just uncheck the box for settling in the guiding tab in the control panel. You can always check it back if you want to use it?


#13

I did that last night. The only issue was that I lost each sub that was dithered due to blurring. I think If I had lowered the settle distance (it was at 2.0) to something around 1.2 I wouldn’t have lost any. So I guess I could do that?

According to the help file:

Settling Options:
Settle at < X pixels For Y seconds (assuming the “For” checkbox is checked): Guiding error amount in pixels that much be reached before a new image will be started. Once guiding is below the pixel amount, it must be maintained for Y seconds in order for the sequence to resume. This prevents the guiding from settling for a split second and then becoming unsettled. Settling will be run:
After a dithering operation
After guiding resumes from “pause guiding during auto focus”

But maybe that’s out-of0date?


#14

Yeah I understand. I was looking to see after I wrote this if I could find a setting for settling on certain frames and could not find anything. How much are you dithering? What is your exposure time? I have mine set to 0.5 pixels for 5 seconds. I normally use 8 seconds but seeing conditions have been so bad that DEC recovery was taking to long and it would screw up my sequence. I have also found that if you have a really good PA that you really don’t have to dither that much. I’m using low dither after 4 frames with 20 minutes of exposure. I’ll be interested to hear what your exposures are.


#15

What does this mean? Is dithering enabled, but only every 11 frames? Or was dithering off altogether?

Regardless, I see no reason why the mount should be settling after every frame. I watched my Mach1 last night and didn’t see these messages when no dither was called for.

At this point Jared and Ken will have to weigh in. I’m at a loss.


#16

If I’m going to be doing a lot of exposures (1000+) then I will dither every 20 frames. If its 100-500 or so then every 5-10 frames. Because I’m using a CMOS (ASI1600-MM-Cooled) my exposures end up being quite short. The longest I can go with Lum is 45s - 1 min. But if I’m imaging something quite bright then I can be at 5s for Lum. I had my settling set to 2.0 for 4 sec and that part seems to work fine.


#17

Sorry Joel,

I ran that quick sequence of 10 frames with a call for a dither on the 11th frame - so basically no dither called for. Both dithering and settling “For” boxes were checked.

Out of curiosity do you have the “For” box checked? I unchecked the “For” box last night and I didn’t get the settling with every frame - but when a dither did run I would loose that frame because it was a bit blurry due to no settling time.


#18

Yeah I do have “For” enabled.
It makes sense that you didn’t get the settling message and resulting delay
without “For” X seconds enabled. That’s what I would expect. That
indicates to me that your mount is off by less than 2px after one exposure
so it immediately starts the next exposure. If you had “For” enabled then
it would pause for 4 seconds and make sure it stays below 2px error before
moving on.

Maybe this is the magic bullet. If you set your tolerance to 1px instead
of 2px and uncheck “For” x seconds, then when the first exposure is done if
the mount is already less than 1px error it will immediately move on to the
next frame. If it is more than 1px error the mount will wait until it gets
below 1px but then immediately start the next exposure.


#19

Ah!! Right On!


#20

Right, that’s what I did last night (lowered it to 1.5px and unchecked “For”).

I remember being told that I should set the “settling” number higher than Total RMS Error, in pixels? Usually my Total RMS number is between 1.0px and 1.7px (.3/.4 arc/sec) so I’ve been using 2.0px. Maybe I’m in error on this?


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