Why does PHD2 not show the Calibration Calculator every time you calibrate?

[boyra...@googlemail.com]

Why does PHD2 not do this? This catches everyone out at some stage. This give the user the chance to review the step size and make sure it is correct for the current dec. At least have a checkbox to do this if you don't want it to behave like this all the time. Thanks!

[bw_msgboard]

Can you describe a specific use case that’s giving you trouble?  It doesn’t “catch everyone out at some stage” based on what I’ve seen – most people don’t pay any attention to it assuming they follow recommended practices.   I can’t picture why a recurring display would be useful.  You shouldn’t need to do calibrations all the time and when you do one you should be doing it near the celestial equator.  If you’re having trouble because the step-size results in a calibration failure, you’re probably re-using the same profile for different image scales, which is also a bad idea.  The specific value of the step-size is not very important as long as the mount moves a reasonable distance, nor does the value really affect the calibration results.  The one computed in the calculator is only an optimization that should result in a calibration that doesn’t waste time but has sufficient data points to get the job done.

 

Bruce

 

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[boyra...@googlemail.com]

If my dec changes it does not adjust the step size automatically.

[bw_msgboard]

It basically doesn’t matter if you stay within 45 degrees of the celestial equator.  The Dec value changes the apparent RA movement by a factor of cos(Dec).  You can play with the calculator and plug in different values of Dec to see what you get.  Even if the value is “wrong”, the RA phase of the calibration might take 15-16 steps instead of 12 – that’s the only implication.  So not worth worrying about and not worth bothering people with a dialog box.  I suspect most users never interact with the step-size calculator at all.

 

Bruce

 

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From: boyracer666 via Open PHD Guiding [mailto:open-phd...@googlegroups.com]

Sent: Tuesday, January 30, 2018 10:54 AM
To: Open PHD Guiding

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[Andy Galasso]

boyracer666,

You may want to consider setting your Aux Mount to "Ask for coordinates".  When you start guiding PHD2 will ask you for the current Declination and you'll have eliminated the need to re-calibrate when you guide at different declination coordinates. Calibrate just once at low declination at the start of session.

An even better option is to set your Aux Mount (or Mount) to use an ASCOM or INDI driver for the mount. But assuming that option is not available to you, then setting Aux Mount to "Ask for coordinates" might be a good option for you.

Andy

[boyra...@googlemail.com]

I always find my calibrations are better if I use the step size for my current dec as suggested by the calc

[boyra...@googlemail.com]

Using ASCOM. Picks up dec ok but PHD2 does not automatically adjust step size.

[bw_msgboard]

I think this is probably illusory and doesn’t line up with what’s actually going on with calibration.  On what basis are you judging the quality of the calibrations?  Doing the cos(dec) adjustment has no effect other than to change the number of steps required for RA calibration, and that effect will be to reduce, not increase, the number.  You can review the code yourself, but I assure you, there is no secret sauce in the step-size calculator. <g> 

 

Bruce

 

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From: boyracer666 via Open PHD Guiding [mailto:open-phd...@googlegroups.com]

Sent: Tuesday, January 30, 2018 11:38 PM
To: Open PHD Guiding

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[Andy Galasso]

boyracer666,

How often are you calibrating? Since you have an ASCOM connection to your mount only need to do a calibration once near declination zero and away from the horizon (close to the meridian),  Select the option to Auto restore calibration.  You can guide without recalibrating throughout the night and from night to night regardless of the imaging target declination or side of pier.  The only time you would need to recalibrate would be if you rotated your guide camera. Even if you setup and tear down each night you can mark the guide camera position with a piece of tape and avoid the need to recalibrate.

Andy

[boyra...@googlemail.com]

Cheers Andy, yes, I use an OAG and so when I rotate I re-calibrate.

[Andy Galasso]

On Thu, Feb 1, 2018 at 2:41 AM, boyracer666 via Open PHD Guiding <open-phd...@googlegroups.com> wrote:

I use an OAG and so when I rotate I re-calibrate.

Ah yes, in that case you're stuck with the re-calibrations.

Just FYI, if you use an instrument rotator with a ASCOM or INDI driver then PHD2 can read the angle from the rotator and automatically adjust the calibration to match. Another solution would be to upgrade to a more sensitive guide camera to make the OAG rotation less of a necessity.

[Brian Valente]

Also FYI if you’re using sequence generator pro, it has the option to request recalibration from PHD on each new target slew

 

 

 

Thanks

 

Brian

 

 

Brian Valente

Brianvalentephotography.com

 

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of Andy Galasso
Sent: Thursday, February 1, 2018 12:53 PM
To: Open PHD Guiding <open-phd...@googlegroups.com>
Subject: Re: [open-phd-guiding] Re: Why does PHD2 not show the Calibration Calculator every time you calibrate?

 

On Thu, Feb 1, 2018 at 2:41 AM, boyracer666 via Open PHD Guiding <open-phd...@googlegroups.com> wrote:

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