[shyrsio]

Let me explain...
The GPS unit when attached or when included, only transmits the position coordinates to the camera. As I understand it, it is a script like Astrotracer that then calculates the way the stars are going to move, depending on the location and time. So it there was a way to dictate the coordinates to the Astrotracer so that it could then do it's magic it would be perfect...
Or am I missing something?

In the same logic one could pair the camera with the phone to get the coordinates from it, since the phone is much faster in achieving this.

Do you think this is a possibility?

[Bob 256]

You need a camera with a moveable sensor and some way to tell the sensor how to move to compensate for scene motion. That generally isn't available in any regular camera (as an external option). A camera with Astrotracer like features, does use position information and plugs it into a fairly complicated program (along with compass and inclination information) which outputs directly to the sensor positioning system so there is no input point for a phone to work.

In any case, how would a phone be faster? When you're setting up to take a GPS referenced shot (i.e., Astrotracer), the GPS is up and running way before you have the shot framed and are ready to take it. Lock times for most GPS-able cameras are nearly the same as phones.

You could theoretically however, use a phone with a computer and guided mount to accomplish the same thing (the phone providing location coordinates to the computer and the computer controlling the mount (you would also need a way to tell the computer how the mount is oriented), but that's a whole different thing unto itself.

[othar]

So it there was a way to dictate the coordinates to the Astrotracer so that it could then do it's magic it would be perfect...Or am I missing something?

I don't think there is a way. As mentioned before, do you not only need your current position, you also need the direction the camera is pointed to (the compass in the phone is probably not accurate enough, even if you have a way to read out and transfer the needed data to the camera).

I guess it would be much easier building a barn door tracker instead.

[peggers]

On a similar subject, how accurate is the external GPS unit compared to say the in body one on the K1? Does anyone have experience with both?. How quickly for example is the signal acquired?

[leekil]

The external one seems to be slower at acquiring the signal than the in-body one. But, I believe the built-in one will update itself continuously/occasionally when the camera is turned off, and it slowly drains the battery this way. The external one, if I recall correctly, loses the coordinates when it is turned off or taken off the camera. The new version that I believe is coming out may behave differently in that regard?

[MossyRocks]

The coordinates from the GPS aren't as critical as people think and even there only the north/south value is the one that matters. Being off by a few miles would have basically no difference on the ability to accurately track so even the worst lock of a few 10s of meters won't matter at all. However what really affects tracking ability is the magnetic compass and getting that accurately calibrated. The camera not only needs to know where it is but also how it is oriented in relation to the center of the earth which is why astrotracer also makes use of the magnetic compass and the electronic level sensors in the camera. I really wish there was a way were one could frame up Polaris in the center of the frame and tell the camera that it was actually pointed with Polaris in the center and then do some movements to calibrate things and finally return to having Polaris in the center of the frame.

On a similar subject, how accurate is the external GPS unit compared to say the in body one on the K1? Does anyone have experience with both?. How quickly for example is the signal acquired?

I have both (K-3 with O-GPS1 and K-3ii) and as far as getting a lock the K-3ii seems to basically have it immediately but the K-3 with O-GPS1 gets it in a few seconds. Neither of these really makes a difference to me since I only use the GPS for astrotracer functionality so playing around with the compass calibration takes more time than that.

[shyrsio]

The coordinates from the GPS aren't as critical as people think and even there only the north/south value is the one that matters. Being off by a few miles would have basically no difference on the ability to accurately track so even the worst lock of a few 10s of meters won't matter at all.

That's the main idea I had in mind, but as it turns out the compass and gyroscopes which input the position of the camera into the Astrotracer take a lot of space too. So I get why they build a block with GPS and Compass and perhaps even with the gyros. getting rid of only the GPS wouldn't make for much saving.