Bad seeing Saturn, but filter testes

[riklaunim]

The seeing was very bad as the weather was changing. Couldn't get anything good, so I've just used the night to check new filter - Baader red "color" filter (not the RGB red filter). It's a longpass filter that pass red and infrared from 610 nm. Other color red/orange/yellow filters work in similar way. This filter is thus brighter than ProPlanet 742. For Saturn it's not easy to get fast framerates and I got this filter to get brighter "L" channel images. Using yellow/orange would yield even brighter image, but for Saturn atmospheric refraction (and seeing if bad) would lower the image sharpness ang quality (without a corrector).

Baader Red 610 longpass; f/26, 21:58:

Astronomik ProPlanet 742; f/26, 22:10:

Exposure time comparison

PP742 - 36.49ms for 70% histogram (27 FPS)

610 longpass - 11.97ms for 72% histogram (80 FPS)

It's fun to record Saturn at "full resolution" at 80-100FPS In good seeing when the view would be stable it could give similar if not better images than the ProPlanet 742 (much shorter exposure - better seeing freezing).

[brianb]

Baader also sell a "IR Pass" filter with the cutoff at 685 nm ... intermediate between an ordinary deep red pass filter and the PP 742. It's actually very deep red to the eye, much darker than the Wratten 29 but the Imaging Source cameras seem to get about the same exposure with the 685 as with the W29.