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Eyepiece comparison for solar observing
I decided to do some solar observing today and took the opportunity to have a bit of a comparison of the various EPs in my kit.
The EPs I used were
25mm Coronado Cemax (came with the scope)
13mm Ethos
13mm Nagler
10mm Ethos
6+mm Delos
Scope used was a Coronado Solarmax 60 with 10mm blocking filter
First thing was that the Ethoi and the Delos looked a little silly on this scope, Big EP, little scope.
That said the views were generally pleasing. The Cemax was the least impressive. Lots of internal reflections and light bouncing around . That said it is easy to get focus and see if there is anything worth looking at at the start of a session.
I have been regularly using the 13mm Nag since I got the scope and have been pleased with its views. Focus is a little trickier than the longer FL but ghosting is minimal.
Unfortunately I am now going to use the 13mm Ethos as my main EP for solar work. No ghosting. Lovely crisp images of proms, surface detail and granulation. Umbra around the 3 groups of spots today were easy to pick up. Entire disc was surrounded by lots of space and the sweet spot was easy to find to get the best detail. Power with both 13mm EPs was 30x.
The 10mm Ethos was also very pleasing. Giving 40x it allows a bit more close up examination of detail. A little tricker to focus and you really need to be aware of the variability of seeing. Again no ghosting and crisp images.
The 6mm Delos gives me 67x so air movements around the sun become obvious. The disc fills most of the FOV in this EP with more power and "only" 72deg AFOV. Views were pleasing but as expected focusing was tricky and you needed to find a bright prom to tweak your focus. Blackouts were annoying but I did find that I could reduce them by observing without glasses! Kind of negates the main selling point of this EP! When I have used this EP at night I found it easier to use with the eyecup raising about halfway as it seemed to reduce the blackouts. Oddly for daytime use this didn't happen and best results were with the eyecup down. All that said when viewing was stready the views were very nice with no ghosting and crisp detail.
Overall I can see the 13E getting some daylight use over this summer!
Malcolm
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