7 replies to this topic

[Distant]

I am unable to find a clear explanation on how to determine the 'Max DEC/RA Duration' values in the ASIAir Guide menu.

 

There are some older threads, one also linking to a well written guide (https://eastwindastr...aggression.html) which explains what this setting means while recommending to usually leave it at default values - 2000ms each. It does not go more in-depth though.

Additionally, the guide is from 2021 and probably does not apply to new strain wave mounts.

 

So I am wondering whether it would still be recommended to keep these default values despite using such a mount type? And if not, is there a way to calculate optimal values or at least a rough rule of thumb?

For reference, for the past months I have been using these values instead of the default but I am not sure if it made any difference due to other setting changes at the same time:

 

My setup is the same as in the signature, guide cam resolution is 6.88''/px and main cam resolution 1.94''/px.

[dx_ron]

If your mount is well-behaved, then you probably aren't sending it any super-long correction pulses anyway. If you do, in fact, need long guide pulses (very large corrections), you want to make sure the correction pulses are not longer than your guide cadence. Otherwise, the program is sending a new command before the mount has had a chance to fully implement the previous correction.

[afd33]

It's been so long since I've had an Asiair, but I believe those are used just during the calibration process. If it takes an excessive amount of steps to calibrate north/south/east/west, then you'd up the numbers until you get it in like 7-10 steps. In general, the longer the focal length of your guide scope, the lower you'll need that number to be.  If when you do a guiding calibration and it works just fine, it's safe to just leave those as they are.

[Distant]

If your mount is well-behaved, then you probably aren't sending it any super-long correction pulses anyway. If you do, in fact, need long guide pulses (very large corrections), you want to make sure the correction pulses are not longer than your guide cadence. Otherwise, the program is sending a new command before the mount has had a chance to fully implement the previous correction.

That sounds logical. I would need to find out the guide cadence somehow and adapt the values accordingly.

[Distant]

It's been so long since I've had an Asiair, but I believe those are used just during the calibration process. If it takes an excessive amount of steps to calibrate north/south/east/west, then you'd up the numbers until you get it in like 7-10 steps. In general, the longer the focal length of your guide scope, the lower you'll need that number to be.  If when you do a guiding calibration and it works just fine, it's safe to just leave those as they are.

I think you are refering to the 'Calibration Steps' setting, not the Max Duration settings. The 'Calibration Steps' setting indeed is only used during the calibration process, and one has to find the value that corresponds to the target steps (I used to aim for 20 steps but lately learned PHD2 recommends 12, so will adapt the values again). Anyway, this value is very easy to determine by trial and error - so I was hoping maybe something similar can be done to determine the Max duration values.

[dx_ron]

That sounds logical. I would need to find out the guide cadence somehow and adapt the values accordingly.

Sorry - bit of jargon there. The cadence is simply how often a new guide image arrives, which is close to being your guide exposure length. So your 400ms setting should be good even down to 0.5s guide exposures.

[Alex McConahay]

Does the next image start before the last correction is complete?

 

Alex

[Distant]

Does the next image start before the last correction is complete?

 

Alex

No it looks like the last correction is completed first.