ERF pre-filter E-170N130 for H-alpha solar monitoring | DayStar

You have an H-alpha filter and want to view the Sun with a larger telescope. Then you need a filter on the front that blocks the heat before it enters the tube. The DayStar ERF E-170N130 does that: it blocks most of the ultraviolet and infrared light and lets through mostly red light. This way the H-alpha filter at the back, like a DayStar Quark, is protected.

The filter comes before the opening of your telescope. If you are using a separate tube, for example one of our Single refractometer tubes, Then measure the outer diameter of the tube or the dew cap.

Before ordering, check that the filter fits without gaps. Never look directly at the sun with an ERF alone: the filter is only safe when part of a complete H-alpha setup. To help with observation, a visor against stray light, Because strong ambient light makes the H-alpha image less visible.

If this size isn't quite right, then adjust it. the ERF pre-filter E-180N130 next to it.