The Altair Dichroic Solar Energy Rejection Filter or D-ERF protects your telescope and solar imaging equipment from excessive heat build-up when solar imaging or observing with your Daystar Hydrogen Alpha Quark, or other Hydrogen Alpha Etalon filters.
We are there: ATT 2023 in Essen The ATT Team of the Walter-Hohmann-Sternwarte e. V. is pleased to announce the date for the next ATT: 13 May 2023, 10 am to 6 pm at the Gymnasium am Stoppenberg, Essen. Stay healthy and see you at the next ATT, your ATT team of the Walter-Hohmann-Sternwarte