ERF pre-filter E-180N130 for H-alpha solar monitoring | DayStar

Anyone who wants to view the Sun in H-alpha with a telescope with a large aperture must first control the heat from the sunlight. The DayStar ERF E-180N130 is designed for this purpose; it is the first filter in an H-alpha setup. It sits in front of the aperture and blocks ultraviolet, infrared, and most of the visible light, while the red light around the H-alpha wavelength passes through.

At the back of the telescope is the actual H-alpha filter. If you prefer not to combine individual parts, our ready-made solar telescopes an alternative.

Choose the ERF based on your telescope: the mount should fit securely on your tube or dovetail ring, without gaps where unfiltered sunlight can pass through. Therefore, first measure the outer diameter. Never look directly at the sun through an ERF. In our guide on solar eclipse warnings Read more about safe observation.

Need a different size, check here the ERF pre-filter E-170N130.