Discounted Daystar E-150n130 Erf 130mm With 150mm Cap For Refractor And Maksutov Style Otas System [bS1vnVei]

Discounted Daystar E-150n130 Erf 130mm With 150mm Cap For Refractor And Maksutov Style Otas System [bS1vnVei]

Designed for use with refractor and Maksutov style OTAs, on-axis, the Daystar filter ERF 130mm with 150mm cap is an aperture-based Energy Rejection Filter that works to reduce the heat load from the sun. It works best with H-Alpha, Sodium and Helium D3 Filters. Heat load is normal, and so should you protect yourself and your equipment and have the best working environment. 

Here's how it works. The refractor either absorbs or reflects the UV and in some cases, IR light. This process is done while the light is being transmitted. The cap is also a solid aperture mask for creating the perfect straight angle of incidence that you need for the light to enter your filter. 

DayStar filter assemblies operate best at f/30 and slower. Creating f/30 configuration can be done easily with the proper ERF and/or barlow. 

IMPORTANT: In the order notes, please specify the telescope this ERF is to be used with, and measure (with a ruler) the outside (largest) diameter of your telescope's dew shield at the very front of the telescope. ERFs are custom machined on a one-off basis and so the accuracy of this measurement is very important. Failing to provide this measurement will cause your order to be put on hold until it is provided.

Features:

• Works Best With H-Alpha, Sodium, Helium D3 Filters
• Good For Staying Safe  
• Protects Your Equipment