[LanceC]

I have not been very successful using astro tracer.
I have a question. if my camera turns off do I need to re-calibrate every time?

So I calibrate and then put it on a tripod and get it pointed in the right direction my camera shuts itself off after 30 seconds.

and should I turn shake reduction off while on the tripod?

[jatrax]

How soon it shuts off is adjustable in the menu. For this I set it to never

Yes, shake reduction should be OFF when on a tripod.

I only calibrate once per location I don't think (but not 100% sure) that camera turning off matters. I do take extra time to get the calibration right.

[kypfer]

I have not been very successful using astro tracer.
I have a question. if my camera turns off do I need to re-calibrate every time?

So I calibrate and then put it on a tripod and get it pointed in the right direction my camera shuts itself off after 30 seconds.

and should I turn shake reduction off while on the tripod?

There is a learning curve ... and working in the dark doesn't make it any easier

From personal experience with my K-70 + O-GPS1, having the camera go into power-saving mode (power down after 30sec) is not a problem, just remember to wait for the GPS icon to turn green again, indicating a "lock", after the camera "wakes up", before making your next exposure.

Physically switching the camera off with the power switch, as when changing lenses, does require re-calibration, but this only takes a few seconds to perform, not the extended period of time experienced when switching on for the first time at a new location.

Shake reduction should be off when on a tripod. The 2sec delay timer (in Drive Mode) is definitely helpful, used in conjunction with a cable release or i/r control is even better. If there's anything more than the lightest of breezes, having the tripod at the lowest of heights that can be reasonably managed definitely helps with time exposures, especially with a longer lens!

Good luck ... and clear skies

[Pelto]

Have a look here:
Pentax Astrotracer Guide: What it is and How to Use it. - MilkyWayPhotographers | Milky Way Photography News and Community for Milky Way Photographers

[MossyRocks]

I have a question. if my camera turns off do I need to re-calibrate every time?

Off off yes, off power saving mode no but you will need to wait for it get a lock again.
As far as how often to re-calibrate I do it every session .
As far as re-calibrating after switching lenses more often than not I don't unless I have a lens made with magnetic material . There is no way I would be able to calibrate it with my 400mm on as I'm not swinging almost 20lbs of long front heavy gear around in fine controlled movements. Instead I stick my 50mm on, lie to it and say I have the 400 on, and then once calibrated mount the camera to the 400mm lens.
If it says calibration complete after 1 or 2 movements it isn't restart the process.
It can take multiple tries to get a good calibration and if I can't get a good calibration after 2 or 3 precise calibrations I start over with a new coarse calibration.
Set your expectations appropriately, the best I have ever managed with a 400mm lens is 20 seconds of tracking. That gives nice round stars even when pixel peeping and I have never been able to go longer than 20s but I can consistently get good 20s exposures at 400mm. If you are shooting at 1/2 that focal length I would expect to be able to track for twice as long. Since I don't do much shooting of astro at 200mm any more but will run a 300mm and a 50mm do get good results at 30s with the 300mm and 100s at 50mm consistently which does support my general rule.
Astrotracer is finicky and takes practice the more you use it the better you will get at using it.
The suggested time provided by astrotracer is overly optimistic see my recommended times.

Some useful tips:
Go past 180 degrees in each movement this seems to provide better results
Ensure smooth movement limited to only 1 axis
Always do a coarse calibration and then do a precise one
I find it works better if the point you have the camera pointed and do the movements around is close to the direction you will be shooting
Avoid magnetic items and things that generate magnetic fields. This includes cars, fences, concrete, power lines, electric motors, buried power lines tripods with magnetic components (steel bolts), soils with high iron concentrations (the iron range in north eastern Minnesota is a prime example of this).

should I turn shake reduction off while on the tripod?

Not expliciatly but using the 2 second delay drive mode will solve a lot of issues. This turns off shake reduction which won't be active for astrotracer anyway, but more importantly will filp the mirror up and then wait 2 seconds before opening the shutter. This allows the camera shake to die down which is really needed with long lenses.

If you really get into astro you will want a big heavy tripod and a big heavy head. Again this solves lots of problems. The tripod I use is one I made myself from 2x4s and weighs in at about 60lbs and I use an old manfrotto 3047 head on it. It is rock solid even when shooting with up to a 2000mm setup.