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Thursday, August 04, 2011

O-GPS1 Astrotracer Examples

Some K-5 users (but no K-r user yet) have started to use the O-GPS1 to shoot star, here are some of the example works and results:-

http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=38967853

This picture is quite good, although not yet astonishing, I think:-


(Click to Expand)

And also test shots from another user:-
http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=39027192


(Click to Expand)

The second picture shows quite clearly that the O-GPS1's astro-tracking function is in action. Just note the locus of the blurred tree and leaves. It seems that the O-GPS1 works good enough for this slow motion application, or at least for those web-sized photos as shown.

Nonetheless, this example shot by a Japanese user does demonstrate some blur, when the picture is viewed at full size:-


(Click to Expand; Warning: Large File; URL: http://pentax.photoble.net/?exif=110802006)

As for the setting up of the unit for astro-tracking, see this previous brief tutorial by the first poster above:-

http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=38927268



Last but not least, if you find that this Pentax unit is just a bit too expensive but you still want to shoot the night sky in tracking manner, here is the cheap DIY solution, for example:-

http://www.flickr.com/photos/snapify/2895746095/



And here is the result:-


(Above: The Milky Way; URL: http://www.flickr.com/photos/snapify/2895789493/)

Wow, what a really nice photo!

I actually made a similar DIY equatorial mount before about twenty years ago and I can also confirm that it does work! Do note that the inclination/elevation angle of the mounting base is based on the latitude of the geographical location of where you are. And of course, if you are at the Northern Earth, you have to point the hinge (which facilitate the rotational movement) to the Sky North and ditto if you are located at the Southern Earth, you have to point it to the Sky South.

Besides, I just wonder if the O-GPS1 astro-tracer/tracker can help in making better super-tele moon shots when shooting in very long focal length, as the moon is always moving fast across the frame in that case (that can be seen through the viewfinder during shooting), which would result in some small blur in the final photos that is particularly noticeable when looking at the pictures closer. :-(

Comments (9)

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Rice -
thanks for this article, and thanks for not bashing Pentax this time. (except for the claims "late" and "expensive", both of which are wrong, since there is no real competition for the O-GPS1 when it comes to astrotracing).
The first two pictures are nice, especially the second demonstrates the astrotracing functionality very well. Compare the second picture (with the trees blurred) with the last (the homemade mount), and you see that the last picture was obviously not a longer exposure, otherwise either the stars or the horizon would be blurred.
1 reply · active 710 weeks ago
The tree "motion" is obvious possibly because of that it is a close object. As for the last picture (the most beautiful one), you do not notice the motion of the far away hilltop just because the stars are moving up/down, as this can be observed on the reflection of the star traces on the lake, of which the effect is actually doubled.
watch grimm online's avatar

watch grimm online · 710 weeks ago

it looks really cool dude...i wonder how much is the price ..
2 replies · active 709 weeks ago
Michael A.'s avatar

Michael A. · 710 weeks ago

$249.95 in USA
Michael, that guy is a typical internet spammer who sells watches online. His links have been removed by me.
Last image creating a big Q in my mind...why star water shadow moving? If sensor is moving with sky then why tree shows are clear ????
1 reply · active 669 weeks ago
Star mirrored images are blur because they were moving in an exactly different direction. The tree *edges* are clear because the star movement was vertical, almost.

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