Image details for full disc: Coronado 90mm Etalon + BF30 filter fitted to a William Optics 102mm ED f/7 doublet lens + AP 0.6x focal reducer = total focal length about 480mm. The image was captured with a DMK51 video camera, processed in Registax and then in CS5.
Image details for closeups: Coronado 90mm Etalon + BF30 filter fitted to a William Optics 102mm ED f/7 doublet lens + Tele Vue 3x Barlow = total focal length about 2145mm. The image was captured with a DMK21 video camera, processed in Registax and then in CS5.
Great pics George and very similar to the resolution I get with a lunt 100 and 3xBarlow.If the seeing permits I find optimal quality is between 3x-4x with this aperture.
Derek
Derek with the Coronado 90 + BF30 I find that a 3x Barlow is about the maximum that I can use. If the seeing is poor then I switch from using the DMK51 + 3x Barlow to a DMK21 + 1.6x Barlow. I think that the faster film rate of the DMK21 is much better in poor seeing conditions especially for solar closeups.