Dither without guiding


#1

As you know there are mounts (10Micron, ASA …) that are capable to made unguided exposures and where PHD is not needed. Now, on SGPro you ca dither only if you use PHD!? Is there any way that SGPro to send dithering command to the mount directly, bypassing PHD?


Dithering without Guiding?!
Meridian Flip not possible without Platesolving & PHD?
#2

Yes, just use the “Direct Mount Guider”.

Thanks,
Jared


#3

OK, thanks Jared!


#4

Jared, we discuss this on 10micron forum and guys said that “Direct Mount Guider” is pulse guiding and dither is measured via camera guiding, so this can’t help us.


#5

I’m not sure what this means. The “Direct Mount Guider” as selected on the SGP Auto Guide Tab of the control panel will “dither” via pulse guiding between frames without the need for PHD or a guide camera. Is this not what you’re looking for?

This is not the case. The “Direct Mount Guider” replaces PHD as the “Guider” in SGP. You would not use PHD if using the Direct Mount Guider.

I’m almost certain the Direct Mount Guider is exactly what you’re looking for unless I’ve completely misunderstood what you’re trying to do.

Maybe you can link to the post on the 10Micron board and I can see what the discussion is about?

Thanks,
Jared


#6

The dicussion is over here: enter link description here


#7

Hi-

I hadn’t realized this was possible. I have a cge-pro and occasionally do unguided short exposure imaging. Can you describe what the dithering procedure would do if you start an image sequence with dithering? Does it randomly move while staying tethered to the original direction? And can you tell me what “medium” and “high” dither would actually mean in that case? Is it seconds of pulseguide, or arc-seconds - or what?

And just for clarity here - SGP does work well for dithering with MetaGuide - but the amount of dithering is specified in MG itself, in arc-seconds. So the SGP medium/high doesn’t have any effect.

My main interest in unguided work is with a dslr and fairly wide lens. I just want it to randomize the pointing a bit and it isn’t critical if the motion isn’t exactly what was expected in a blind dither call - especially with dec. backlash. So it sounds like this feature - if I understand it - should work fine for me.

Thanks,
Frank


#8

I think this is a good feature too.
There should be an option to dither with Goto commando since then the 10 Micron mount will then update refraction settings. 10 Micron mounts won’t update refraction if the mount is nudged.
There should be an option for how many arcsecs it should dither and i think the max dither should be calculated from the initial position of the imaging session so it won’t move further and further away from the initial position over time


#9

The Direct Mount Guider will move the mount by a using the pulse guide interface of the mount. It pulses the motor for a certain amount of time based on the selected dither amount.

Small - 100ms
Medium - 250 ms
High - 500ms
Extreme - 1 second

Depending on your guide settings in your mount this can equate to different amounts of dither. For 1x sidereal guide value this means 15 arcseconds per 1 second guide pulse.

Thanks,
Jared


We're gonna need a bigger dither
#10

I just got into the 10 Micron forum but it sounds like everything was resolved by the above post?

Thanks,
Jared


#11

Per has realesed a new ASCOM driver for testing the Direct Mount Guider option.
Hope to work and to hear good news from testers, I can’t test it, I’m out for a while!


#12

the need is to update the mount parameters while no image is taken.
So one solution was to consider that a sent pulse during a dither would act as a trigger to update theses parameters.
But if one needs to updates these parameters , and need to guide, this will go wild.
In that way i like much better to update the parameters thanks to a script.
But from now, no script can be launched beetween frames, only beetween events.


#13

Triggering an update from the pulseguide sent during a dither wouldwork, but would need an option to be turned off in Per’s driver so people actually guiding wouldn’t have problems because of this option.


#14

Actually for testing purposes he release an driver version with this option.

http://filer.frejvall.se/FrejvallGM_6.6.6.1.Setup.exe


#15

sorry… opened a new topic now


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