solar telescopes

[lesbehrens (Les)]

great thats good.
over the double stacked PST vs a SM 40 what would u choose?
les

Originally Posted by Merlin66

No, is the answer. The new blue coating doesn't have any real energy rejection component to break down; it's just like a normal telescope objective. I don't know of anyone having any problems with the "Blue" PST's.

[Merlin66 (Ken)]

Both have merits!
The double stacked sm40/PST gives improved resolution (0.5A), but is still limited by the focal length ( 400mm) and construction of the PST ( the use of the penta prism). Remember that the SM40 filter used to double stack is the same as the one in the SM40 stand alone system.

The only difference is the addition of a sparate blocking filter built into a diagonal. These BF's can have larger apertures which gives wider fields for viewing and can be used on longer focal length scopes.
So, the SM40/BF10 type arrangement can be used on almost any refractor up to say 1200mm fl, and gives cleaner images; the PST is always ( unless you start doing mods) limited to the 400mm fl and the constraints of a BF5 filter.
Hope this helps.

[lesbehrens (Les)]

thank you for your help.
les

[lesbehrens (Les)]

one last question. how well can u see filaments so the surface of the sun with a PST?are they very distinctive or is it a skill to see them?
thanks
les