UV/IR cut filter for WL solar.

[Franklin]

I have been watching the Sun for decades, firstly via projection, then with a full aperture filter and now I have a Lunt wedge(1.25"). The wedge has an internal ND3 filter as you know and I use a single polariser and a Baader solar continuum filter on the eyepiece. The views from this setup have been amazing and I am very pleased with kit I have. Recently I have been reading the forums and I have noticed that some people are reconmending the use of a UV/IR cut filter ahead of the solar wedge. Is this necessary for eye safety or is it mainly for use with imaging? 

[Luke]

I've got the Lunt 1.25" wedge too, just been using it a few minutes ago. Lovely bit of kit and great value!

For visual the UV/IR cut should not be needed. The only reason I would consider using one for visual is if the telescope seemed to be getting very hot. My 120mm scope seems fine when using the 2" Baader Herschel wedge and the views are so crisp I find it hard to imagine a UV/IR cut would improve things. No harm trying though I guess.

For imaging, I found the UV/IR cut made a big difference with my Tele Vue 85. Without it, the image was fuzzy. With my Equinox 120mm, however, the UV/IR cut appeared to make no difference. My best guess is that the Schott glass used in the Equinox 120mm cuts IR.

So based on my experience I would say it depends on your scope - and could be camera too - and is worth a try for imaging if you have one hanging around.

Edited September 11, 2021 by Luke

[Stu]

On 10/09/2021 at 18:33, Franklin said:

Is this necessary for eye safety or is it mainly for use with imaging?

Not needed for eye safety. I did recently add one to my CoolWedge but that was largely in an attempt to improve my dodgy smartphone images.

[Mark at Beaufort]

I use a SvBony IR/UV filter when visually observing. I may not really need it but it just gives extra assurance and piece of mind.