Velours Film matt black 100x45 cm - self-adhesive, for blackening the tube

Velours Film matt black 100x45 cm - self-adhesive

The film absorbs most of the incident light, thus reducing stray light and increasing contrast.

Blackening telescope tubes

Pimp your telescope with a pitchblack interieur is a step that helps you increasing the instruments optical quality. Take a look from the side into the tube without velours and you will notice the reflecting surface. That stray light causes a decrease in contrast.

The self-adhesive Velours swallows stray light and gets rid of reflections. The tubes interieur gets much darker and the image quality increases dramatically.

Is it necessayry to do that for the entire tube?

The optimum is a completely coated tube wall. However a remarkable improvement shows up if you do the following:

for Newtonians you just coat the focusers opposite part of the tube. This is where stray ligth has its biggest effect.

for a refractor, the front 2/3th of the tube are necessary as the last third is being covered by the focusser´s tube.

Blackening of focusers and similar connectors

Here, grazing light incidence occurs, which even anti-reflection grooves can reduce only moderately. This not only causes non-directional stray light, which reduces the contrast, but also directional light, which leads to disturbing brightening in certain areas. If you now stick on velour film, the image field becomes "clean".

Note: Some telescopes, especially Maksutov-Cassegrains, have a narrow, tubular baffle in front of the eyepiece connection. If velour film is used, vignetting will appear at the edges. This is no problem when observing planets only, otherwise the use of anti-reflection paint is preferable, which is linked below under the designation TSBlack250.

Blackening the dewcap

Also for dewcaps, velour coating really makes sense. It not just helps increasing contrast, it also augments the entire surface and therefore helps getting rid of dew problems.

Attaching the velours

The film arrives well protected on a roll. When attaching the velours, please take care for a neat and clean working area that is free from dust. If you have any dust on the velours, you can easily use a lint brush to clean it.

For attaching the velours, you should also demount the optical elements. Take out all lens elements or mirrors. Then use a sharp cutter to customize the film. Deduct the backside film and stick the velours to the inside tube wall.

Sometimes it makes sense to use smaller pieces to get rid of problems with bubbles or tricky parts inside the tube like screws or baffles.

Practical tip: Some of the hairs are loose. After application, run a lint roller over the foil, then the hairs can no longer fall onto optical surfaces.

Safety informations: PDF Download