Flocking a telescope


Making good astronomy observations is best done on a dark sky. The higher the contrast between the light from the stars and the darkness of the sky is the more details can be observed. Unfortunately living in Europe, as I do, most sites have some of the sky polluted by city light. One way of increasing the contrast can be by using an optical filter like the LPR or UHC filters. These filters work by allowing the wavelength typically associated with astronomy to pass (like Hydrogen and Oxygen), while eliminating other wavelengths. The downside of the filters is the amount of light is decreased, this means that for visual observations you will need a bigger telescope.


If you live in a suburban area, with reasonably dark skies and limited city lights, you should consider the ”Flocking” mod, as an alternative to the optical filters. I have dark skies and two street lights outside my garden, the flocking modification definitely decreased the stray light going into my newton telescope. Giving me better observations.

I will describe how it is done.


The Flock paper used for the modification can be found on Edmund Optics homepage:



The first thing to do is cut the flock paper into long peaces about 3 to 5 cm. Wide, and prefrebly as long as the telescope. Also best to make all the peaces at once.

The entire telescope will have be disassembled. To ensure that the holes in the telescope tube match those in the mirror support i marked the two peaces, this will give a less problematic re-assembly.


The rest of the telescope is deassembled, I'd put a cover over the mirrors, to avoid dust.


The flocking paper is put into the telescope tube, about 1 cm. Above the bottom where the mirror is normaly placed. The paper must be cut along the tube front when all the paper has been placed. Dont worry about covering the holes, these can be opened with a knife afterwards, or the screws can be pushed through.

The difference is obvious.


The telescope is reassembled, the mirrors are collimated and the result is a much darker telescope tube. Looking at the skies afterwards definitely improved the contrast of the sky. The modification is cheap and easy to do, and I would flock any future newtons I get my hands on.


Clear Skies

Andreas Taarning





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