Lunt Hershel wedge & polariser

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
Post Reply
Allcart
Im an EXPERT!
Im an EXPERT!
Posts: 496
Joined: Wed Jan 09, 2013 1:59 pm

Lunt Hershel wedge & polariser

Post by Allcart »

I've just bought a 2" Hershel wedge with the Polariser. The polariser is only a single element filter. All my polarisers to date have been 2 glass elements that rotate against each other to adjust the contrast.
This filter obviously screws into the base of a 2" EP, so does it work in conjunction with the ND filter in the wedge, or is there an element missing from the supplied filter.


Allan
brianb11213

Re: Lunt Hershel wedge & polariser

Post by brianb11213 »

1. You absolutely positively need the ND3 filter installed somewhere ... and it should be on the output side of the wedge as the heat flux on the input side is dangerous.

2. The light reflecting from the wedge disgonal surface is pretty well plane polarised so you really need only one rotatble polarising filter placed on the output side of the wedge to control the intensity. Actually a non-rotatable filter screwed into the eyepiece works well, just rotate the whole eyepiece.

3. Personally I prefer to use a green or orange filter instead of the polariser (you get more contrast because of the physical nature of polarising filters). The Baader Solar Continuum works best but an ordinary green colour filter is quite effective.

4. You absolutely positively need the ND3 filter installed somewhere ... and it should be on the output side of the wedge as the heat flux on the input side is dangerous.

Yes I do know I've made that point before. It's vital for safety. Extra filtration is only for comfort & convenience.


MjrTom

Re: Lunt Hershel wedge & polariser

Post by MjrTom »

Good summary Brian!

I find that if you are using a 4" refractor or larger with an ND3 filter the polarising filter really helps to subdue the brightness to a comfortable level for visual use.
For imaging I would ditch the polariser as you preferably want the shutter speed as high as possible to freeze the seeing conditions.

Mark


Allcart
Im an EXPERT!
Im an EXPERT!
Posts: 496
Joined: Wed Jan 09, 2013 1:59 pm

Re: Lunt Hershel wedge & polariser

Post by Allcart »

Thanks for that Brian. The wedge already has a ND3 filter pre installed so the polariser should work ok then. As always, I only need a bit of sunshine to test it out.


Allan
Post Reply