One of the treats of the trip to AstoPalma was the chance to use the 40cm relay cassegrain. This is an interesting design where all the optical surfaces are spherical and therefore easy to make but, there are rather more of them than in a conventional design. The focal point is inside the telescope tube and a small lens is used to ‘relay’ this point back to the eyepiece. Details of the optical design are here.
The main camera on this telescope is an SBIG ST8XE using the SBIG Adaptive Optics unit for guiding. Limited time meant that we only acquired a single 10 minute frame for each colour but we did get 4 luminance frames of the same length. The result of this was some pretty bad colour artifacts which required judicious use of the spot healing brush in PhotoShop. So, the result is here.
