[ilpostino]

I have wanted O-GPS1 for ages but put it on hod when i found out Pentax is releasing the O-GPS2. Does anyone know if K3 is going to have support for O-GPS2?

[kypfer]

As the O-GPS2 is touted as being a replacement for the O-GPS1, (which apparently has gone out of production due to parts supply issues), it's highly likely that it will be totally backward compatible, even if it does have some extended capabilities which may not be available to older cameras.
I would anticipate that use of a GPS module is aimed at a fairly small sub-set of total Pentax users, it wouldn't be sensible to alienate a proportion of those who've chosen not to update to a newer camera

[Sidney Porter]

If you think about it the k3 is only 3 models back that really need it for Astro. I have to think Astro is the intended target
-K3iii can use astrotracer3 via firmware
-K1, k1ii and k3ii built in GPS

That leaves the KP, k70 and k3 as the most recent potential buyers

I assume the gps2 will be smaller, do away with the blue light and make it red. Maybe rechargeable. Could it be powered by the hotshoe? I don't know how much tech has advanced for the actual receiver I assume some of it is software

[kypfer]

If you think about it the k3 is only 3 models back that really need it for Astro. I have to think Astro is the intended target
-K3iii can use astrotracer3 via firmware
-K1, k1ii and k3ii built in GPS
That leaves the KP, k70 and k3 as the most recent potential buyers
I assume the gps2 will be smaller, do away with the blue light and make it red. Maybe rechargeable. Could it be powered by the hotshoe? I don't know how much tech has advanced for the actual receiver I assume some of it is software

I think "most recent potential buyers" is possibly limiting the field too much … my K-5 (with firmware update) works perfectly well with my O-GPS1, it's larger battery making it an ideal candidate for multiple long exposures, especially if the temperature is a bit on the low side!
A brief review of all the DSLRs produced in the last 10 years or so suggest that most of them can be used for 'astro', even if a firmware update is required … the K-01 being the glaring exception, only being able to use the GPS for positioning!
There is probably a proportion of existing "older" Pentax camera owners who may consider updating to "astro-capability" without wanting/needing to otherwise upgrade their camera.
As for the potential O-GPS2 itself … changing the blue LED for red is a very good idea, rechargeable, not so much. I've needed to replace the AAA cell in my O-GPS1 at short notice in the past, having to wait for the unit to charge would have possibly meant a missed opportunity.
I don't think there's facility in the Pentax hot-shoe to provide power.
I don't mind the size of the existing unit, I'd even put up with it being a bit larger if it meant that the necessary "chicken dance" calibration procedure could be made more reliable with less need to have to repeat.

[Sidney Porter]

My point was that they will be backward compatible rather than implying that it would only be to the k3. I stopped at the k3 because that was the camera the OP was asking about

[Not a Number]

Since the description of the unit is "GPS unit for K-mount digital SLR cameras" and not for a specific model I would expect compatibility with cameras the work with the O-GPS1. Since the O-GPS1 doesn't work with my K10D I don't expect the O-GPS2 to either. And I'm not going to expect a firmware update for a camera that had it's end-of-life years ago.