Stopping down a ST120

[Donkeiller]

Does anyone know whether dewshield caps for refractors are sold separately?

Even better with if they come with bigger seconday stops than the standard 50mm?

I'd like to convert my ST120 (f/5) to a 70mm f/8.6 on occasion:)

[Peter Drew]

Just make one out of cardboard and tape it on to the front of the dewcap. Fiv minute job! .

[mark7331]

Does anyone know whether dewshield caps for refractors are sold separately?

Even better with if they come with bigger seconday stops than the standard 50mm?

I'd like to convert my ST120 (f/5) to a 70mm f/8.6 on occasion:)

Ok I am a little confused. What do you mean when you mention "bigger secondary stops". A dew shield doesn't change the focal ratio of a scope. If you'd like to use a different F-ratio then you'll need a focal reducer or something like a barlow.

Also you can make a dew shield yourself from a camping mat or even a piece of cardboard.

You can make a cap according to your own specifications if you'd like to change the aperture but - why? You'll end up with a scope that captures less light.

Mark