Solar observing with a Herschel filter

[skybadger]

Hi all

I have both a Vixen Visac and a NA140, both of which use tertiary optics.

I want to use them to look at the sun using my Herschel filter which means full aperture viewing before hitting the prism and dumping heat before further filtering using crossed polarisers for brightness control.

What are the safe limits to the tertiary optics?

Cheers

Mike

[Merlin66]

Herschel wedges were designed for simple achromatics.

I would NOT recommend using them on any other type of scope.

Use the Baader Solar film.

[skybadger]

I recall using it quite happily with my SP102. But as you say, simple achromat.

Cheers

Mike

[E621Keith]

I am sure I have seen people using APO refractor with solar wedge, but only ones with front elements only.

Mirror scopes are no go.

[johninderby]

I've had no problems with regular APO's but really an achromat is just fine.

A Celestron / Skywatcher 102mm f/5 has surprisingly sharp optics and can be picked up fairly cheaply. The standard 2" focuser's not the best, but at least a standard replacment crayford fits so that'd be an option later on. That would be what I'd go for now if buying a cheapish dedicated OTA for solar white light.

John