Posted 13 November 2012 - 07:00 PM
f/20; 20:39 UT; YRGB and Redlum-RGB; DMK21AU618 + ADC:
Yellow and RedLum channels:
1.5x drizzle YRGB:
Some collimation testing at f/10 and f/20:
Posted 13 November 2012 - 07:45 PM
Posted 13 November 2012 - 08:53 PM
Posted 14 November 2012 - 01:41 AM
Posted 14 November 2012 - 06:03 PM
Fun playing below:
Nothing ground breaking by any means, but a newbie (me) playing around and learning
During a night of on again off again cloudy skies, I ran a few tests to determine whether the swirling pattern I was observing was due to temperature fluctuation inside the OTA or atmospheric diffraction. I took temperature readings over a 4 hour time period measuring both ambient air temperature and temperature inside of my OTA. The purpose for me was to observe how much the delta between ambient and air temp affected viewing and how altitude played a role.
Even when temperatures had stabilized and were within one degree of each other, the image was still distorted, but what I had discovered (so not ground breaking) it was due to the altitude of the object observed when out of focus. The closer I got to Zenith using Capella as my test object, it nearly dispersed, but when I would move back to Polaris at 44 degrees it was very noticeable and simulated the temperature flux most of us are familiar with. Looks very similar to Piotr's image.
I discovered so many things that night that indicated I needed to change about my set up to help the OTA cool down quicker when imaging. I couldn't believe how little it took for the swirl pattern to re-appear and long it would take to stabilize. Fun stuff.
Posted 14 November 2012 - 07:00 PM
That does seem like a pretty nifty idea and gave me an idea of how to build a similar unit for a lower price. I have several spare air pumps lying around from my other air mattresses that I do not use. Those would be the perfect application for this.
Posted 15 November 2012 - 01:59 AM
Blows the air through the OTA. And when the scope is used a mini version:
This one is attached to one of fork mounting holes. In both cases air escapes via other holes around the primary. They blow away any boundary layer out there and make the scope cool down much faster