AstroSolar and TurboFilm Mounting Suggestions



Making an inexpensive cell for BAADER AstroSolar Film or TurboFilm optical-window.
The film must be mounted flat and free of any tension - Only this will provide first class optical properties. The quality of this patent pending material is so high that any strain on the film will lead to a very noticeable deterioration of optical quality (it is preferable to have a few mild wrinkles than to place the film under stress from pulling it).
When mounted carefully, AstroSolar and TurboFilm can reach the quality levels of truly precision polished glass plates (not to be compared with the commonly available glass filters made of ordinary window glass w/o ever having seen a polishing machine).

The "Cylinder"
At first you have to produce a cylinder of cardboard, to exactly match the outer circumference of your Telescope tube or dew cap. In order to achieve this, cut a whole number of cardboard layers, approx. 5 -6cm (2 inches) wide. Wrap one piece of cardboard around your dew cap or lens cell and glue one end onto the other. Abbildung: Zylinder

Fasten a second and third (and so on) layer of cardboard in the same manner, until you have manufactured a stiff roll of cardboard, approx. 4 - 5mm (3/16") thick. Watch out that the finished "cylinder" will slide snuggly over the tube and that it will be easy to slide it on and off the telescope.
Hint: For telescopes with smaller aperture one could try to find an appropriate "poster tube" and cut off a piece of approx. 5 - 6cm length. Variations in diameter can be compensated for by using adhesive felt liner or by gluing Cork pads into the paper tube.

The "Window Cell"
Cut out two rings of cardboard (each having 1 - 2mm thickness). The outer diameter of the ring - shaped cardboard should match the outer diameter of your fabricated "cylinder". The inner diameter should correspond to the actual aperture of the instrument.
After having prepared two such rings, both should be equipped on adjacent sides with a large number of small cutouts of double tape along the outer circumference of both rings. Now comes the tricky part - how to get the AstroSolar or TurboFilm onto the taped ring w/o wrinkles or ripples. The film must not be scratched - so put one sheet only of Kleenex (or other soft tissue) onto a flat table. Tape the Kleenex onto the table so that this part is stretched out evenly and cannot move on you. Only now put a square piece of film - (precut to the size of the cardboard-rings) onto the piece of soft tissue. Do not tape the film and do not stretch it! Just let it rest relaxed and flat on the Kleenex.

Please Note:  Before mounting the AstroSolar, be sure to peel off the removable clear protective film that is present on one side of the film.

Abbildung: Scheiben

Abbildung: Objektivfassung

Now take the first cardboard ring and lower it straight down onto the film until every double tape clipping made contact with the film. Turn this package around, tape the other ring onto the opposite side and cut away the overleaf. Now your AstroSolar or TurboFilm TM should be mounted free from strain and wrinkles between the two cardboard rings. Finally glue this "window holder" onto the prefabricated "Cylinder". Now your "Do it Yourself" precision Solar Filter or Optical Window is ready. Enjoy it - you just saved about $100 - for the filter cell alone.
When covering a larger Newtonian or Cassegrain Telescope for Planetary Observation, you may want to also try an "off axis filter cell".  The reduced aperture may enable your large telescope to perform to the level of a good refractor (by eliminating the central obstruction and effects of turbulence on the larger aperture).  Or. for maximum resolution, a full axis filter can be made from our new Maximum sized AstroSolar (46" x 46").


last updated 05/15/05


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