Originally posted by Bcrary3 Is the O-GPS1 needed for astrophotography? Also, the tripod I have is an (old) Slik U-212 would this be sufficient?
What is a PK tether? haha Never heard of it. And for a lens I'd be inclined to use my Sigma 21-35mm f/3.5-4.2 (seems like a quality lens in my opinion never been able to find any reviews on it though).
Also, I'm curious to know what aperture is commonly used and what shutter speed or how long of a bulb/timed exposure is often used, as well as criteria for good locations to do it at.
Required. No, its not. Astrophotography has been around since photography began. The O-GPS1 is unique to the Pentax system because it uses our Shake Reduction megnetic sensor to move and compensate for the apparent movement of the stars/objects.
PK tether allows you to control the camera via USB cord thereby minimizing vibration and allowing you to change settings, unlike an IR remote, and view the image on the computer screen immediately after it is completed. As for specific settings, take a look at the various threads and examples. There are lots and the EXIF data can be very helpful with regard to settings.