PHD2 Auto Restore Calibration - a real time saver

[Startrek (Martin)]

I’ve been using PHD2 guiding ( Ascom pulse guiding , not ST4 ) for nearly 4 years now at two different sites and the last time I performed a calibration at both sites was nearly a year ago. I use the Auto Restore Calibration function in PHD2 which is a real time saver.
Both rigs have the guide scope and it’s guide camera fixed on a Losmandy bar across the tube rings so I can pull the whole OTA off the mount with guiding gear ( down south in my NexDome the rig stays put whilst in Sydney I collapse my rig twice or three times a year and bring it inside ) and calibration is not affected.
If I had to calibrate at both sites every time I imaged, the additional hours would certainly add up over a year.
When I first used Auto Restore Calibration I was expecting to re calibrate after a month or so , but just kept using it ( without any issues ) until I realised after nearly a year I haven’t calibrated this rig for a long long time.
For those who use PHD2 ( Ascom Pulse Guiding ) , do you take advantage of the Auto Restore function and how long have you used a good calibration for ?
Thanks .....

[Startrek (Martin)]

Hmm...
No one uses PHD2 for guiding on their laptop ??
I guess iPhones and tablets are the new way to image now using an ASIair , wifi etc.. seems everyone’s buying them now .......

[The_bluester (Paul)]

Didn't see this one til now.

I recalibrate when I change camera angle (With an OAG) and that is it. When I was using a guidescope I calibrated once and left it alone for about 12 months, same same on the odd occasion I use the built in iGuider in my CEM70G (As it is fixed and does not change calibration with the main camera being rotated)

If the calibration is good and you have not changed anything that changes the guider angle or image scale or something mechanical on the mount, then the calibration is good. All the calibration does is determine which direction on the guide camera is which on the sky and how fast the mount moves for a given length guide pulse, so IMO it it not something that gets stale and needs redoing with time like a master dark for image calibration. you have to change something for it to become invalid.

[Drac0 (Mark)]

Because I'm working on getting my mount 'right' I seem to be calibrating several times a night as I make changes. But generally I don't change the calibration - though I may start doing it after meridian flips once everything is working well enough.

[Startrek (Martin)]

Originally Posted by Drac0

Because I'm working on getting my mount 'right' I seem to be calibrating several times a night as I make changes. But generally I don't change the calibration - though I may start doing it after meridian flips once everything is working well enough.

In PHD2, if you are using Ascom pulse guiding ( guide camera direct to laptop ) which is the preferable recommended option by the PHD2 developers Andy Galasso and Bruce Waddington , meridian flips do not affect calibration
Ascom Pulse Guiding is just another advantage over the older ST4 method ( guide camera to mount )
With the older ST4 connection method you have keep calibrating regularly, a painful unnecessary process

[Drac0 (Mark)]

Originally Posted by Startrek

In PHD2, if you are using Ascom pulse guiding ( guide camera direct to laptop ) which is the preferable recommended option by the PHD2 developers Andy Galasso and Bruce Waddington , meridian flips do not affect calibration
Ascom Pulse Guiding is just another advantage over the older ST4 method ( guide camera to mount )
With the older ST4 connection method you have keep calibrating regularly, a painful unnecessary process

Good to know. Was just that sometimes when calibrating and something has gone wrong it comes back with "have you done a meridian flip". Never actually used ST4 guiding - by the time I started guiding I went straight to pulse guiding in PHD2.

[The_bluester (Paul)]

Actually, with regard to ST4 guiding, you can guide with ST4 and still have information from the mount so that you do not need to constantly recalibrate on every change of pointing, if you are controlling the mount via ASCOM. You can chose ST4 guiding but select your mount driver in the "Aux mount" setting. But if you can pulse guide, I would. If you are pulse guiding, or using the aux mount feature, some mounts require the dec guiding to be reversed after a meridian flip. There is a meridian flip assistant that can tell you if that is needed or not. It calibrates the guider east of the meridian then asks you to slew to a point west (Causing a flip) and calibrates again to see which way the dec guiding runs. Then it will tell you to select it or not.

It is pretty simple to tell anyway, if you are pulse guiding and the first Dec guide pulses after a meridian flip cause the star to run away off screen faster and faster as the guide pulses increase Whatever the "Reverse dec output after meridian flip" box in the guide tab of the PHD2 brain is, you need to reverse it.

[Startrek (Martin)]

Originally Posted by The_bluester

Actually, with regard to ST4 guiding, you can guide with ST4 and still have information from the mount so that you do not need to constantly recalibrate on every change of pointing, if you are controlling the mount via ASCOM. You can chose ST4 guiding but select your mount driver in the "Aux mount" setting. But if you can pulse guide, I would. If you are pulse guiding, or using the aux mount feature, some mounts require the dec guiding to be reversed after a meridian flip. There is a meridian flip assistant that can tell you if that is needed or not. It calibrates the guider east of the meridian then asks you to slew to a point west (Causing a flip) and calibrates again to see which way the dec guiding runs. Then it will tell you to select it or not.

It is pretty simple to tell anyway, if you are pulse guiding and the first Dec guide pulses after a meridian flip cause the star to run away off screen faster and faster as the guide pulses increase Whatever the "Reverse dec output after meridian flip" box in the guide tab of the PHD2 brain is, you need to reverse it.

Paul,
Thanks for the tip
I think I read something in the PHD2 manual about this
Martin