The Player One S series filter uses high quality optical glass and multi-layer composite coating technology, which results in excellent optical performance in astrophotography.

1.25inch ERF filter ( Energy rejection filter for Quark Chromosphere）

This filter is an assistant filter, design for Quark Chromosphere (Ha version) , intended to reject energy and extend life time of your Quark.

1.25″ ERF filter works on 5″ or smaller refractors.

(DO NOT use it on eyepiece for observing)

Why add a ERF on Quark?

First filter on Quark is quite small, the solar disk might bigger than it, the light will heat the filter and it’s holder. With this 1.25″ ERF filter, we can protect both the filter and filter holder from high temperature.

And don’t worry about the ERF itself, it’s use B270 transparent glass and multi coating, it will reflect not absort most energy.

Does it has any other usages?

Yes, this ERF filter also can be used in Lunar imaging, it will provide even brighter image than IR685 filter, also could improving the seeing.

Specifications

Specifications: 1.25 inch, thread M28.5*0.6

Frame thickness: body 5mm+ thread 2.5mm, a total of 7.5mm

Thickness of filter lens: 2.5mm

PV: 1/4 lambda

Transmittance: ≈97%

Blocking depth: OD4 (200nm-1100nm)