
"Baader" Solar Filter from China
#26
Posted 11 October 2021 - 08:17 AM
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#27
Posted 12 October 2021 - 10:01 AM
I bought a Gosky solar filter for use with my 5 1/2 inch Original
Cometrron on eBay for 50$ and it works fine - appears to be Baader Film and instructions says same -it has a white light n sunspots we’re fine - many years ago Tuthills Solar Skreen was about the same like Mylar film
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#28
Posted 17 November 2022 - 03:20 PM
Though I'd add my experience. Bought a full aperture 8 inch sun filter from China for 50$ (see signature) .. and it works great for visual and imaging.
If in doubt, use an UV/IR filter.
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#29
Posted 17 November 2022 - 08:46 PM
#30
Posted 17 November 2022 - 11:14 PM
What is the effective difference between the the Beloptik KG3 IR/UV and the Baader IR/UV ?
[Aside to David: Hi David, just wanted to let you know that the Jaeger's 80mm is still safe and looking for a suitable tube. Definitely not forgotten, and definitely much appreciated.]
My understanding is that the KG3 provides an extra safety net for the very long IR. The typical UV/IR filter is a rejection coating, but the KG3 (or equivalent) is absorptive. The KG3 catches the long IR that a typical UV/IR might pass.
As far as I've been able to understand, the Beloptik provides both in a single unit. In my own application, I combined a cheap UV/IR filter with GRB3 glass (KG3 equivalent), I bought the latter, put it in a sacrificial 1.25" filter cell, and use them both on the nose of my diagonal.
If the Baader you're referencing is the same (or similar) to what's published on this reference sheet
https://agenaastro.c...-stat-sheet.pdf
, notice the graphs and the statement in their third bullet point. My takeaway is that the implication is that the absorptive KG3 is not not enough, but you can clearly see in their charts that some long IR still gets through. Hence the utility of KG3 in addition to UV/IR.
What I've learned about this has been mainly from this thread. Hopefully Marty and others can step in and add greater clarity, as I am still much the junior here.
Safe Seeing,
~ RA
#31
Posted 20 November 2022 - 03:07 PM
Looks right. One other tool many people have available is their astronomy camera, which covers most of near IR. You can use that as a sensor to double-check that your system is not leaking any dangerous near IR, looking for blurriness, haziness, or anything if you happen to have an IR-pass filter. It is very sensitive and some leak is fine for visual. If you insert and remove an IR filter and the exposure does not change much, then there is probably not too much near IR.
For example, my 5303A filters are rated from 200nm to 2000nm but do I trust them? It's a reputable company (Andover), I have the 200-2000 spectrograms for those two specific filters, and my camera exposures are a second long, implying no bright near IR coming through.
George
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