Trico Macnine Products "Sky Window" - Pickup Only in Los Angeles, CA.

Up for sale is a late friend's "Sky Window" by Trico Machine Products.  For those unfamiliar with the Sky Window, it is a first surface mirror and binocular mount that makes it possible to look downward into one's own binoculars, yet effectively be "looking" up into the sky with them. To do this, the binoculars "look" downward toward the Sky Window's first surface mirror. This facilitates more comfortable observing, where an observer can look downward into the binocular eyepieces.

The Sky Window is essentially an 8" x 10" first surface mirror that is mounted on a structure that allows it to be moved in one axis to select the elevation angle for an object of interest in the sky. Pointing in azimith is accomplished by moving the entire unit on a tabletop or tripod. The Sky Window comes with a blue anodized aluminum mirror cover and a two page manual that appears to only be a copy.

To hold an observer's binoculars, the Sky Window has an additional metal part that is oriented vertically. This part is angled at the top and includes a 1/4-20 bolt. The upper end supports binoculars that have an axial 1/4020 screw thread at the front of the focusing mechanism of a user's own binoculars. The Sky Window is intenedd for binoculars that have this type of axial tripod mount, and that also have at least 12mm of clearance between the objective lens cells.

Therefore, since the vertical metal part of the Sky Window is about 12mm thick, its thickness makes the Sky Window incompatible with certain roof prism biniculars, including models such as the Vortex 12x50. (That's why none of my pictures show binoculars mounted on the Sky Window.)

It is still possible to use such binoculars by placing the Sky Window is on a table (or low on a large tripod), and then mounting your binoculars on a tripod, oriented to look down into the mirror at a roughly 45 degree angle.

The mirror of the Sky Window is only about 6mm thick, so it is not flat enough to use with telescopes or large aperture binoculars. (I tried a Meade ETX 90 OTA and some 25x100 binoculars with it, and the images were not good at all.) Some mirror aberrations are even visible on one side with 12x50 binoculars, but these are relatively minor.

I would generally say that 10x50 binoculars are the largest aperture and highest magnification that should be used with the Sky Window (at least this sample) if small images of brigher stars are desired. Slightly larger binoculars will work if there are no bright stars in the field, but even 70mm binoculars may be too large to work well on the Sky Window.

Even though the Sky Window is not an excessively large or heavy item, it is pickup only in Sunland, CA (northern Los Angeles) because I am often unable to travel to even mail stuff. The available pickup times are only from mid afternoon through the evening. There is a slim chance that this item could be shipped IF the buyer can arrange to provide a fully prepaid shipping label that does not require my needing to have an account with the shipping company. (Not sure if that is even possible.) Clear Skies.