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01-08-2013, 11:42 PM - 1 Like   #1
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Astro Tracer (OGPS1) question

Greetings all, I am wondering if any Astro Tracer users have come across the following results - see attached pic (IMGP2705), which is a 2 minute exposure. I have had success so it's not that all images are looking like this - far from it, I think it is a fantastic addition to the kit, and it gets some nice "oohs" and "aahs" from the Canikon crowd

I am using the 70-200mm f2.8 from Tamron.

I have also uploaded a 60 second exposure of the Orion nebula to show that things are going right sometimes too! The mind boggles at what could be achieved with a longer lens...

Luke

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01-09-2013, 02:22 AM - 1 Like   #2
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HI LukeOB,

The trailing in itself indicates a failure in calibration. That can and will happen now and then for many reasons such as local magnetic disturbances, errors in reading of the focal length, changes in satellite positions........ But the kink in the trails could indicate that you have attempted to track the stars beyond the freedom of the sensor to move. I have had similar experiences myself.

I can see that you have taken the shot at 200mm FL and a 120s exposure so, what central star (declination) are we looking at?
01-09-2013, 06:25 PM   #3
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QuoteOriginally posted by Stone G. Quote
HI LukeOB,

The trailing in itself indicates a failure in calibration. That can and will happen now and then for many reasons such as local magnetic disturbances, errors in reading of the focal length, changes in satellite positions........ But the kink in the trails could indicate that you have attempted to track the stars beyond the freedom of the sensor to move. I have had similar experiences myself.

I can see that you have taken the shot at 200mm FL and a 120s exposure so, what central star (declination) are we looking at?
Thanks for the reply Stone. It is a shot of Jupiter which is stunning in the northern sky at the moment. I guessed it might be something like you suggested ie callibration, as I am getting nice images at other times as I continue shooting during the evening. Here's another shot, this time the Large Magellanic Cloud, when things worked well. 3 minute exposure, and no weird kinks
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01-10-2013, 12:46 PM   #4
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Now tha is a nice cloud LukeOB! I've only had - mostly rainy - clouds to look at since some time in October 2012. My O-GPS1 is surely beginning to get impatient.......

Regarding your first, "kinky" picture: These days, Jupiter has a declination of +21 degrees and thus, you are very close to the stated limit of trancking time with a 200mm lens and a K-5, wich is approx. 110 seconds near the celestial equator. This might explain the kink. There is also the possibility of an intermittent "fall-out" in the workings of the sensor actuators. Such things also do happen once in a while and the remedy is, as always, a "reboot" of the camera.

01-13-2013, 05:30 PM   #5
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Thanks Stone, actually I seem to have had some pretty lousy weather since picking up the Astro Tracer (roughly the same time as you by the sounds of it!), and now its mid summer and it isnt properly dark until 10 or 11 or later so I haven't been getting out too often. Appreciate the suggestions, I usually dial in a shutter speed just under the maximum allowed, although I notice it change from time to time which seems strange - maybe there are some internal shanannigans going on. Rebooting is always a good option isnt it!!
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