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- Sat Jul 07, 2018 6:49 am
- Forum: Solar Scope Modifications
- Topic: Front ERF vs Internal ERF? Minimum size?
- Replies: 27
- Views: 1177
This is a bit late but I have a warning about sub-aperture, internal D-ERFs: There is a fiercely hot, refocused and unfiltered , reflected Solar image well in front of my 6" f/8 [120/10] objective. I'm using a 90mm internal Baader D-ERF with PST H-a filtration in an old CR150HD donor. Fortunately, m...