K5 and Astrotracer

I have recently searched for information on different approaches to astro-photography. On the major Norwegian photography forum (www.foto.no), users of Canikon talk about checking out the Pentax K5 because of its compatibility with Astrotracer, and thereby its suitability for astro-photography. I really do not understand much of this? Is it a kind of GPS system that compensates for the earth`s rotation? Do any of you have any experience with Astrotracer?

The Norwegian forum discusses this link:

http://forums.dpreview.com/forums/readflat.asp?forum=1036&message=39284452&chang...

Bjørn

Very clever indeed! Let us hope this attracts more photographers to Pentax

What kind of a rig does one use with astrotracer? Is it only useful for dslr + lens + tripod, or can it be used with dslr + telescope combinations?

Presumably you can use it with a telescope, but I think the longer the focal length, the shorter the time period which can be corrected for.

Bjørn

I don't have the O-GPS1 myself but recently photographed the constellation of cassiopeia on a standard equatorial drive & uploaded the image to the gallery for reference. Anyone with the O-GPS1 unit might find this useful to compare their results with same kit & settings, this was a single exposure of approx. 2mins so should be within the limits of the O-GPS1.
I would expect the unit to operate at optimum with lenses close to standard up to around 200mm as in the linked article above, wide angle lenses would probably have too much distortion while long focal lengths would require faster tracking of the sensor with less time to capture enough light at a reasonable ISO setting for sensor noise.

Mike

Mike and Pentaxophile: Thank you for your responses to my inquiry, I do believe I understand more of the idea behind the Astrotracer now. For my own part this is at the moment only of general interest, I have neither the equipment nor the technical competanse to attempt expanding into this area. But Astro-photography is an outmost intriguing area within photography, I believe

Mike: I have looked-up your "Constellation of Cassiopeia" photo, and also your flicker gallery - very impressive stuff!

Bjørn

Bjørn

Thank you, very kind, unfortunately I enjoy the taking the images more than processing so many images have never seen the light of day so to speak.

I could can see the O-GPS1 being a very handy addition for those taking undriven starry vistas at high ISO settings. The ability to freeze the motion of the stars for just an extra 15-30 seconds more than usual could make the difference between shooting an astro scene at 1600 rather than a noisier 3200 ISO.
Could also allow the lens to be closed down an extra stop for better quality star images across the sensor. Of course the horizon may still show some blurring but never as obvious as high contrast stars leaving trails if not intended

Congratulations must go to Pentax for such an inovative product.

Mike