Altair D-ERF CUSTOM SIZE Energy Rejection Filter

To order an Altair Energy Rejection Filter with a holder for custom size optical tubes, we need the following information:

• Aperture of telescope and model
• Bezel Diameter and depth in mm
• Optical tube or dew-shield diameter in mm
• Whether there are any protrusions beyond the bezel, E.g. a Newtonian secondary mirror, which can interfere with the ERF glass.
• What wavelengths you want to image with, i.e. Hydrogen Alpha, Calcium H, Calcium K, all combined etc.

Please refer to the diagram showing the parts.

You can contact us here with this information, and we will quote you for a custom Altair ERF to suit your optical tube, large or small.

Please note this product cannot be ordered online due to the customisations, and it can take a couple of weeks to complete.

We ship worldwide by insured guaranteed courier.