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07-07-2014, 09:37 AM   #661
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Very good. Can you tell what modifications did you make to your K-5?

07-07-2014, 10:44 AM   #662
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Full spectrum modified by Kolari Visions. They remove the internal UV/IR cutoff filter and replace it with an optically clear glass. It also lets me (using on the lens filters) take UV or normal visible or IR images. They also adjusted the autofocus for a 50mm lens so my autofocus still works with normal dslr lenses.
07-07-2014, 03:03 PM   #663
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So, it's like what Baader and Hutech are doing for Canon. Very good. I didn't know that is possible for Pentax. Thank you.
07-07-2014, 04:39 PM   #664
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And the sensor in the k5 is an unbelievable cmos sensor. Very very low read and thermal noise. Very ideal for astrophotography.

07-08-2014, 05:25 PM - 1 Like   #665
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DSLR Cooling

Anyone cooling their Pentax K5 out there? Here is what I'm going to do. I saw quite a good study on the sensor showing that every 5 to 7C reduction in sensor temperature will cut thermal noise in half. My solution is not a fancy one. It will bolt to the tripod bolt hole and fit tight against the bottom and back. Next I will be trying it with the camera to see how much it will cool it down. I'm hoping to get at least 14C cooler than ambient at the sensor. If you look at the cut away view there is a lot of metal from the sensor to the frame's metal... sooo I'm hoping for the best!

If anyone out there is doing this let me know!
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07-10-2014, 05:58 AM   #666
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Well it cooled the sensor by 11C. So that should lower my thermal noise to a third of what it would otherwise be seeing. Any reduction in noise is a good reduction in noise during long exposures!
07-10-2014, 06:26 AM   #667
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QuoteOriginally posted by seti_v2 Quote
Well it cooled the sensor by 11C. So that should lower my thermal noise to a third of what it would otherwise be seeing. Any reduction in noise is a good reduction in noise during long exposures!
Is that a muffin fan attached to the heat sink? If that is the case, wouldn't this be a possible trade of thermal noise for mechanical vibration?

07-10-2014, 07:39 AM   #668
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QuoteOriginally posted by seti_v2 Quote
Anyone cooling their Pentax K5 out there? Here is what I'm going to do. I saw quite a good study on the sensor showing that every 5 to 7C reduction in sensor temperature will cut thermal noise in half. My solution is not a fancy one. It will bolt to the tripod bolt hole and fit tight against the bottom and back. Next I will be trying it with the camera to see how much it will cool it down. I'm hoping to get at least 14C cooler than ambient at the sensor. If you look at the cut away view there is a lot of metal from the sensor to the frame's metal... sooo I'm hoping for the best!

If anyone out there is doing this let me know!
Using a liquid cooling block may be a better idea, portable battery back to run the pump, radiator/reservoir. Vibration free and make the camera unit itself smaller.

07-10-2014, 08:00 AM   #669
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Don't feel any vibration with it but have tried it under the stars yet either. My mount is pretty rock solid though and doesn't shutter in mild wind so I may not see any vibration issues. I will hopefully get to try it out Saturday.
07-10-2014, 08:11 AM   #670
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QuoteOriginally posted by steve500 Quote
Using a liquid cooling block may be a better idea, portable battery back to run the pump, radiator/reservoir. Vibration free and make the camera unit itself smaller.
You would want a nice smooth pumping action - not one that pulses, since that too would cause a shutter to be induced through the fluid column.

Actually, I believe that there are some pumping systems that are based around the thermal fluid expansion within the heat sink, that moves the fluid column along. That should be the smoothest of all.

07-10-2014, 07:53 PM   #671
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Not sure if lunar photography belongs here or not, but we had a clear sky in Michigan last night and I couldn't resist that bright light up above.
K-5, DA 55-300 @ 300mm f5.8, 1/320sec, ISO 400, 1:1 crop. There are some adjustments made in Light Room. I'm geeked with the results. Love the craters in the lower left.


Last edited by rextang; 07-10-2014 at 08:01 PM.
07-11-2014, 05:48 PM   #672
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QuoteOriginally posted by rextang Quote
Not sure if lunar photography belongs here or not, but we had a clear sky in Michigan last night and I couldn't resist that bright light up above.
K-5, DA 55-300 @ 300mm f5.8, 1/320sec, ISO 400, 1:1 crop. There are some adjustments made in Light Room. I'm geeked with the results. Love the craters in the lower left.
Good result!
07-11-2014, 09:49 PM   #673
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For sure, lunar photography belongs here. And the result is good, regarding the lens used.
07-15-2014, 07:21 AM - 1 Like   #674
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Lagoon Nebula (M8)
19/06/2014 - Near Toulouse (France)
K5 + O-GPS1 + 300 mm 5.6 + tripod photo
Stack: 6 images ISO 800 or 1600 F6.7 (6 x 30 sec)
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07-30-2014, 10:03 AM - 1 Like   #675
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Ic 1396

IC 1396 the elephant's truck nebula.

My make shift cooler cooled the sensor down almost 20F below ambient so all in all not too bad. Polar alignment of the mount was a little off though.

13 x 900" exposures at ISO 400 through Astrodon 6nm H-a filter
Orion F5 120mm achro scope on NEQ6 Pro mount
Full spectrum modified Pentax k5 with homemade cooling

Full res link: IC1396 Elephant's Trunk in False Color H-alpha (seti_v2) | AstroBin
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