Titan shadow transit animations 29th April 2009

[Quark]

Hi All,

Here are two short animations, each has only three RGB images.

These R, G, & B files were captured every 20 minutes.

The first animation uses images captured before my primary mirror temp stabilized at .5 C below ambient.

The second animation uses images captured after the primary mirror temp stabilized, they are very high res.

Thanks for looking
Regards
Trevor

[RobF]

Wonderful work as always Trevor.

Is it just me, or is the shadow on Saturn quite a bit oblong, even allowing for seeing etc?

[h0ughy]

excellent work Trevor

[Screwdriverone]

Sensational Trevor!

Gee those rings are starting to tilt again!?!

Nice work, still yet to try this event, well done.

Cheers

Chris

[iceman]

Beautiful work, Trevor. Excellent colour on the disk and the moons are very nice and round.

Well done!

[StephenM]

Fantastic animations, Trevor! Great job.

Cheers,
Stephen

[Quark]

Thanks Stephen



Thanks Mike, the difference between the two data sets is an excellent example of what active cooling can deliver.



Thanks Chris, glad you liked them. There are still some more opportunities this apparition to image shadow transits.



Thanks Houghy



Thanks Rob, the oblong shadow in the first animation is due to instability in the boundary layer of air at the surface of my primary mirror, due to the temp of the mirror being more than .5 C above ambient and also from the air flow caused by the cooling fans of my active cooling system.

In the second animation the mirror temp has stabilized at .5 C below ambient and the cooling fans have been turned off long enough for the air currents around the mirror to settle.

[kinetic]

Trev,

nice work and a great example of your efforts!
I wonder if the boundary layer/ cooling thing would
also apply to long exposure deep sky stuff too? :shrug:

Thanks for sharing the research Trev, inspiring!

Steve

[Quark]

Thanks Steve,
The instability of the boundary layer of air across the primary mirror is most apparent with planetary imaging due to the very high magnifications most imagers are using. The high magnification also magnifies this disturbance of the boundary layer. At low mag, prime focus with a DSLR or similar it wouldn't be as big a problem, that said, considering some of the higher mag deep sky work that you have been doing, it might help. The results at high mag really are significantly better with the mirror within +- .5 C of ambient.

Regards
Trevor

[RobF]

Thanks for explaining Trevor. Seeing the difference in the two images and the details of the temps quite educational. Had wondered about affect on other types of imaging too, so glad to hear thoughts on that too. Certainly makes you think about value of temp monitoring and decent airflow for serious observing/photography.

Rob