Sunday, 13 April 2014

CaK Sun on a Sunday - 13th March

I was testing out a new configuration for CaK imaging today; using the 100mm frac but stopping it down to 80mm using the Beloptik Tri-band filter.  The slightly smaller aperture should make it better when the seeing is poor, and in todays boiling sky the filter proved it's worth.  I much prefer mounting these ERFs externally rather than internally, as it is much easier to be in control of the ghost / reflections.  The swathe of activity that has come over the eastern limb looks great in CaK wavelengths.
In addition there was a lovely flame prom visible on the southwestern limb of the sun as the following image shows: