ERF-Filters

ERF (Energy-Rejection-Filter) are essential components for solar observation. They protect the telescope and eyes from the high-energy radiation (IR heat radiation, UV radiation) and enable narrow-band filtering for observation and photography.

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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.
595.00 €
Delivery date : 2-4 weeks
 
 

Altair 130mm Aperture Energy Rejection filter - Ha Hydrogen Alpha only D-ERF for 5" Refractors

Product Features:

  • Reduces approx. 98% of heat reaching the optics to keep Etalon from drifting off-band and protect your equipment.
  • 30-40nm FHWM Bandpass at H-alpha (H) wavelength of 656.28 nm (Full Width Half Minimum) Transmission: ~90%
  • UVIR blocking OD3 0.1% @400-1100nm blocking over 98% of heat to your 3rd party Etalon at eyepiece or camera end, E.g. Daystar Quark). Please note it's your responsibility to use a proper commercial Etalon with this product, and to follow the manufacturer's instructions.
  • Visible light blocking: OD4 0.01% @400-700nm to reduce reflection effects and over 98% of heat.
  • Diameter 140mm Thickness 12.0mm 
  • Multilayer coatings with SiO2 protective overcoat.
  • ERF Holder cell included with soft tip threaded knobs. Tough and very light, easy to disassemble for cleaning the filter with optical wipes. Cell does not put any tension on the optics and will not scratch or damage your telescope. It also won't alter the balance as much as an aluminium cell.

799.00 €
Delivery date : 2-4 weeks
 
 
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.

  • Reduces approx. 98% of heat reaching the optics to keep Etalon from drifting off-band and protect your equipment.
  • 30nm FHWM Bandpass at H-alpha (H) wavelength of 656.28 nm (Full Width Half Minimum) Transmission: ~95.5%
  • 40nm FHWM Bandpass with CWL at 395nm covering Calcium H-Line and Calcium K-Line wavelengths. Transmission: ~90.5%
  • UVIR blocking OD3 0.1% @400-1100nm blocking over 98% of heat to your 3rd party Etalon at eyepiece or camera end, E.g. Daystar Quark). Please note it's your responsibility to use a proper commercial Etalon with this product, and to follow the manufacturer's instructions.
  • Visible light blocking: OD4 0.01% @400-700nm to reduce reflection effects and over 98% of heat.
  • Diameter 140mm Thickness 12.0mm (required to achieve surface precision)
  • Multilayer coatings with SiO2 protective overcoat.
  • ERF Holder cell included with soft tip threaded knobs. Tough and very light, easy to disassemble for cleaning the filter with optical wipes. Cell does not put any tension on the optics.
929.00 €
Delivery date : 2-4 weeks
 
 
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 ...
1429.00 €
Delivery date : 2-4 weeks
 
 

The Altair 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 Ha Quark, or other Etalon filters.

1739.00 €
Delivery date : 2-4 weeks
 
 
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.
729.00 €
Delivery date : 2-4 weeks
 
 
DayStar Energy Rejection Filters reduce the heat load on your filter assembly by absorbing or reflecting UV and/or I light and transmitting light in the desired visual spectrum. 
829.00 €
Delivery date : 3-4 weeks
 
 
DayStar Energy Rejection Filters reduce the heat load on your filter assembly by absorbing or reflecting UV and/or I light and transmitting light in the desired visual spectrum. 
829.00 €
Delivery date : 3-4 weeks
 
 
DayStar Energy Rejection Filters reduce the heat load on your filter assembly by absorbing or reflecting UV and/or I light and transmitting light in the desired visual spectrum. 
829.00 €
Delivery date : 3-4 weeks
 
 
DayStar Energy Rejection Filters reduce the heat load on your filter assembly by absorbing or reflecting UV and/or I light and transmitting light in the desired visual spectrum. 
829.00 €
Delivery date : 3-4 weeks
 
 
DayStar Energy Rejection Filters reduce the heat load on your filter assembly by absorbing or reflecting UV and/or I light and transmitting light in the desired visual spectrum. 
1189.00 €
Delivery date : 3-4 weeks
 
 
DayStar Energy Rejection Filters reduce the heat load on your filter assembly by absorbing or reflecting UV and/or I light and transmitting light in the desired visual spectrum. 
1189.00 €
Delivery date : 3-4 weeks