Lunt

[CeeDee47]

Can any kind person please explain to me what size of circular polarising filter I need to fit my Lunt 80THa  DS2 scope?  I also need confirmation on how it works as if the filter is 'inside' the DS2 etelon then I would presume that in order to rotate it to get the best contrast you simply release the thumb screws holding the elelon and rotate it until the 'sweet spot' is found.  Then tighten up. Am I right???

I already have Lunt's anti reflection filter installed but I am still getting a bright halo around the solar disc which does not make for clear images of the proms.

Thanks in advance to any respondents.

[LDW1]

You attach it to your eyepiece, just like any other scope type, probably 1.25" I have never seen a 2" diagonal on that scope but maybe I have just missed it !  There are other combinations to attach it but thats my method, let others fill you in on the alternatives.

Edited July 8, 2023 by LDW1

[LDW1]

As I reread this I am finding it harder to comprehend your post. Are you wanting to rotate a built in filter or are you looking at using an external variable polarizing filter ? If so with the ds it may make it pretty dark viewing or ap'ing.

[Highburymark]

I hoped that the Lunt anti reflection filter would largely fix the problem, but it appears not. Your best bet is to ask the same question on Solarchat, where there are a number of member who have had the same issue. Haven’t seen it covered on SGL. It was the glow that put me off the LS80DS - otherwise such a fine scope. But I’m sure Solarchat will help you.

[CeeDee47]

54 minutes ago, LDW1 said:

As I reread this I am finding it harder to comprehend your post. Are you wanting to rotate a built in filter or are you looking at using an external variable polarizing filter ? If so with the ds it may make it pretty dark viewing or ap'ing.

I read on Cloudy Nights that one successful strategy is to add a cpf between the etalons. I can't see how a cpf would work unless you actually rotated the etalon in which the cpf is installed. By their very nature cpfs are rotatable. I have used the in photography in the past.

[LDW1]

48 minutes ago, CeeDee47 said:

I read on Cloudy Nights that one successful strategy is to add a cpf between the etalons. I can't see how a cpf would work unless you actually rotated the etalon in which the cpf is installed. By their very nature cpfs are rotatable. I have used the in photography in the past.

Just watch you don't play with fire !  The Solar section of CN have some pretty expert astronomers that have a wealth of knowlege with regards to your question(s) and everything else pertaining to ha / wl. Good Luck !

[Starflyer]

It's this a new scope or old?  I ask because my Coronado SM II 60 showed a similar image when the ITF filter was failing.

[Highburymark]

4 hours ago, CeeDee47 said:

I read on Cloudy Nights that one successful strategy is to add a cpf between the etalons. I can't see how a cpf would work unless you actually rotated the etalon in which the cpf is installed. By their very nature cpfs are rotatable. I have used the in photography in the past.

I think this was the solution I read about on Solarchat too. But it was several years ago.