Just doing a little experimenting last night with my M85 f2 shot at f2.8. I didn't really get to evaluate it ,as the astrotracer was way off the mark. I did the calibration before putting it on the tripod, and I used a wired intervalometer set to 60s exposures with 15 secs between shots.

As you can see, the Astrotracer was moving almost horizontal, while the stars were moving diagonally. This resulted in vertical lines for stars. I have had some good success with the Astrotracer before, but not last night.



This makes me wonder if it is better to just shoot multiple short exposures and stack the images'

Was it windy? There's no obvious horizontal component to the star trails. While the astrotracer clearly didn't track well, superficially the trees look as if wind blown.

60s using a 85mm lens is also, to my experience, pushing it, I usually use the 300/focal length rule (K-70/APS-C) 500/focal length (FF) and multiply that by 10,
I've discovered that shooting direction is also impacting the exposure time, shooting north usually allows a longer exposure time than shooting south, I guess that has to do with angles and the rotatinoal speed of the earth.

Don't you need to be in "Bulb" mode for Astrotracer function, or is K3 programming different? I have K5IIs with O-GPS1.

Check your tripod head. I bought one from Amazon which looked nice and solid but I couldn't get any decent images with it. I then switched to my Manfrotto head and the same settings yielded very good shots.

Are you sure Astrotracer was actually on? That's not me being patronising, it's just that on the K3-II you have to be very specific about it - sometimes it can look like it's on when it's not. I had mega problems with mine (amplified by me being a total novice - the K3-II is my first DSLR). Add to that the fact that sometimes the calibration doesn't seem to "stick" and it can be very challenging.

Edit: this guide was put up by a vastly more experienced astrophotographer than me, but he doesn't have a K3-II so the bits about that are mine...maybe it will help?

nightfallphoto

Astrotracer was definitely on. The star movement is diagonal across the sky. The the lines of stars would be diagonal if the astrotracer didn't move the sensor. The sensor moved horizontally at the same rate as the stars. There just wasn't a vertical component to the movement of the sensor, hence the vertical lines of the stars.

Thanks for the link to nightfallphoto. I wonder about the intervalometer hanging from the camera, and if that have an affect on the sensor movement.

I hang mine off it too, doesn't seem to bother it...except for when it does...as I said getting good shots is a bit hit and miss with it...I've had perfect pinpoints and long smears from shots on the same night, with the same settings.

IIRC there are two "levels" of calibration to the astrotracer. Did you get "calibration" and fail to get "precise calibration"? I don't know how that would affect the astrotracer function, but the notes at Ricoh's site indicate you need to use the precise calibration for astrotracer: Calibration | GPS UNIT O-GPS1 | RICOH IMAGING

Clearly the sky is falling! ;-)

For me looks like the camera is slowly "slipping" down. Usual issue with some tripods. Especially, if you are taking "vertical" shots.