Filtre ERF S-Serie 2" pour Chromosphère

/! \ Attention this filter should not be used without full opening filter /! \

Filter of the Player One series using a high -quality optical glass substrate and multi -layer composite coating technology, which has excellent optical performance in astrophotography.

2" inch ERF filter (energy rejection filter for chromosphere）

This filter is an assistant filter, made for the Chromosphere Quark (HA version version), reject part of the energy and thus extend the lifespan of your quark.

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 2″ 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 usage?

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.

Features

• Specifications: 2inch, thread M48*0.75
• Frame thickness: body 5mm+ thread 2.5mm, a total of 7.5mm
• Thickness of filter lens: 2.5mm
• PV: 1/4 lambda
• Bandwidth: ≈60nm
• Transmittance: 97%
• Blocking depth: OD4 (200nm-1100nm)