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ASIAir Plus guide calibration.

ZWO ASIAIR Sky-Watcher EQ6-R Pro ZWO ASI2600MM Pro ZWO ASIAIR Plus Guiding
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Pete Carpenter avatar
Pete Carpenter avatar
Recently I have noticed a new trend while calibrating for guiding on the Air plus. I have the Calibration step set so that calibration completes in around 6-7 steps but have noticed that the sequence goes west step 1-2-3-4-5-6-7- east step 3-2-1 and the same with the north and south steps. I'm sure it used to read 1-2-3-4-5-6-7 7-6-5-4-3-2-1 ??  Just wondering whether this is a feature of the latest update to the software and if anyone else has noticed it. Last night was the first clear night since the end of November and therefore the first time out with the air updated. Guiding performance was not impressive but this could have had something to do with the 85%moon. 
Any input appreciated. 
Thank you. 

Skywatcher EQ6R Pro
ASIAir Plus
William Optics FLT 91
ZWO 2600mm
ZWO OAG
John murphy avatar
John murphy avatar
Pete
  My setup is similar except for an AM5 & mounter 50mm guide scope .  But my guide steps were like yours 1-7/8 & 1-7/8 for all N,S, E, W.   I have not been out in a bit aw we have rain here and heavy overcast.
Have you seen this guiding tutorial by Peter Zeninka?   It has some really good information.
 Guiding Tutorial
Rick Krejci avatar
Rick Krejci avatar
I run PHD2 through Nina (which is what the ASIAir guiding is based on) and it behaves the same way (more steps out than back).
Henric avatar
Henric avatar
Pete Carpenter:
Recently I have noticed a new trend while calibrating for guiding on the Air plus. I have the Calibration step set so that calibration completes in around 6-7 steps but have noticed that the sequence goes west step 1-2-3-4-5-6-7- east step 3-2-1 and the same with the north and south steps. I'm sure it used to read 1-2-3-4-5-6-7 7-6-5-4-3-2-1 ??  Just wondering whether this is a feature of the latest update to the software and if anyone else has noticed it. Last night was the first clear night since the end of November and therefore the first time out with the air updated. Guiding performance was not impressive but this could have had something to do with the 85%moon. 
Any input appreciated. 
Thank you. 

Skywatcher EQ6R Pro
ASIAir Plus
William Optics FLT 91
ZWO 2600mm
ZWO OAG

Yup, I have the same issue(?) with my GTi and it has been so for a while now (3-4 months).

I think it happened after a firmware update with mine.

I would also like to know the cause and if this is supposed to be like that.
Pete Carpenter avatar
Pete Carpenter avatar
Thank you gentlemen for your replies. It’s comforting that it’s not just my set up. CS
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MaksPower avatar
MaksPower avatar
The guider caculates everything in pixels based on the camera sensor axes. During the calibration, it is working out how far the guide star moves when nudged by the guider, and it does this by issuing 7-8 pulses measuring the total movement. It also uses the guidescope focal length and the guide rate set (0.25, 0.5 or 1.0X sidereal) to make an estimate to start with.

It appears that as at version 2.3 of the firmware (December 2024) ZWO realized  for any practical mounts, the distance per guide pulse east = the distance per guide pulse west, so only need to 8 steps in one direction to measure the response of the mount, then quickly bring the guide star back to centre. And there's no backlash in RA since the motor doesn't reverse direction. Ditto declination, once backlash has been measured.

And it speeds up the calibration process.
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Pete Carpenter avatar
Pete Carpenter avatar
Many thanks for the explanation, I now understand. CS