GPCs are solely designed to compensate for the spherical error that is induced into the beam when a large chunk of glass (in this case all the combined prisms built into a binoviewer) would otherwise create a huge color error. So unfortunately, no, a GPC can never replace a barlow lens.
Answer by: Baader Web Team (Admin) on Sep 28, 2023 9:08:00 AM
Since we sell neither Bresser telescopes nor Hexafoc focusers, unfortunately we can't answer this question with confidence. Please inquire the exact thread dimensions from Bresser to see if it will fit.
Answer by: Baader Web Team (Admin) on Sep 28, 2023 9:14:00 AM
Since we don't sell neither Explore Scientific telescopes, unfortunately we can't answer this question with confidence. Please inquire the exact thread dimensions from Bresser to see if it will fit. Please note that we have various RT-Adapters available, if the focuser should not fit natively: https://www.baader-planetarium.com/en/catalogsearch/result/?q=RT-adapter
Answer by: Baader Web Team (Admin) on Sep 28, 2023 9:31:00 AM
As you describe, this is exactly the procedure we recommend. Coarse impurities are removed with a blower, then the mirror can be gently cleaned with our Optical Wonder Liquid and the enclosed microfiber cloth. Alternatively, you can use original Kleenex tissues in combination with our Optical Wonder Liquid. However, make sure that you are using the original Kleenex cloths without any additives.
Answer by: Baader Web Team (Admin) on Sep 21, 2023 12:27:00 PM
Our company exists now for more than 50 years. In this time, more than 15.000 Baader Planetariums (the first patented product of our company) help all over the world to give students an understanding of astronomical correlations. In our own manufactory, more than 500 observatory domes have been produced and delivered turnkey-ready. Instruments and telescope accessories from "Baader" are known for their high qualities by many astronomers and universities. We consider it our duty and obligation, not only to sell telescopes, but an indivdually selected telescope system, that brings you a lifetime of joy.