ANTLIA ENERGY REJECTION FILTER 150mm

The Antlia 150mm Energy Rejection Filter is a multi-coated dualband filter designed to reject the majority of light at both ends of the spectrum, with two narrow transmission windows of only 25nm half-bandwidth around the H-alpha and Calcium-K & -H lines. This enables safe usage of H-alpha and Calcium solar filters with telescopes by preventing as much extra energy as possible from entering the telescope.

The 130mm ERF is suitable for use on telescopes with an outer diameter at the very front of the dew shield measuring between 150 - 220mm.

Antlia energy rejection filters block almost all extraneous light, ensuring that the etalon in your h-alpha filter does not degrade over time and that the central wavelength passed by the etalon stays on-band. By being placed at the front of the optical path, this provides the additional benefits of reducing turbulence inside the telescope and protect against off-axis rays hitting the walls of the tube, which could damage the telescope.

The Antlia ERF is a finely polished heat resistant substrate with advanced multi-coatings and a transmitted wavefront of Lambda/4 or better. The included mounting cell allows you to install it on the front of your telescope securely.

Warning: This filter cannot be used on its own to observe the sun! Doing so can cause irreversible damage to your eyes and equipment. A separate H-alpha solar filter such as the Daystar Quark or Baader SunDancer is required.

Features

• FWHM 25nm with CWL at H-alpha wavelength of 656.3nm; Transmission: T＞95%
• FHWM 25nm with CWL at CaK wavelength 393.3nm covering Calcium K-Line 393.3nm and Calcium K-Line 396.8nm; Transmission: T＞90%
• Coating Range: 200-1700nm wavelengths
• Finished with the most advanced multicoatings
• Coated on heat resistant double-polished substrate
• Antlia ERF 130mm, 150mm, 200mm filters are mounted in a housing/cell to hold it in front of the telescope
• Transmitted Wavefront: Lambda/4 or better.

Specifications