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Equipment: Sky Window & Binoculars

Telescope and Eye-pieces SkyWindow and Binoculars filters accessories

The Sky Window & Binoculars


I love to observe the moon, open clusters and double stars. They are beautiful when viewed through a telescope. Rich star fields and large open clusters are also among my favourite observing targets. I prefer to look at these objects through low or medium power binoculars rather than through my telescope. In my opinion, binoculars are the only instruments that show these large objects in their full glory.

When I started with binocular astronomy, I quickly became aware of the fact that for me, there was a serious downside to binocular observing. After half an hour of observing I had to stop because of the pain in my neck and lower back. I always have been suffering from lower back pain, so I had to find another, more convenient way to observe the night sky with binoculars. I tried almost everything: lying on my back on a mattress, leaning against a fence-post, sitting in a reclining chair, even mounting the binocular on a camera tripod. Nothing worked for me. I started looking for a special mount, like a parallelogram binocular mount. During my search I stumbled into a "new" product, the Sky Window, a binocular mirror mount manufactured by Trico Machine Products. In Sky and Telescope it was "Hot Product of the Year" (2001). I decided to order the Sky Window online and within 48 hours UPS delivered it.

The Sky Window fully assembled

The Sky Window is very easy to set up (a manual is included and can be downloaded from Trico Machine's website). As you can see on the image below, mine came in seven major parts. It was assembled within minutes. You just have to look at this beautifully crafted piece of equipment to see that it is built to last a lifetime! The Sky Window is made of machined and anodized aluminium and the mirror is a "first surface" aluminized mirror. Its a full 1/4 inch thick for dimensional stability, and has a quartz overcoat for scratch resistance.

The Sky Window as it came out of the box

How to observe with the Sky Window?

You attach the binocular to the Sky Window with a lock knob. You then put it on a table or mount it on a tripod. After that you just sit down on a chair and start looking into your binoculars, as if you are looking into a microscope. You look at a reflected image of the night sky in the mirror. You can observe from the horizon up to the zenith just by moving the mirror up and down. If you want to move to the east or to the west, just turn the Sky Window to the left or the right. Also have a look at the diagrams on the Sky Window pages of Trico Machine Products. You will understand the working of the Sky Window immediatly.

Mounting the Sky Window on a tripod enables you to adjust the height, and you can tilt it into an even more comfortable observing position. I leave the binoculars mounted on the Sky Window permanently. Together, they weigh about 5 kilograms, a weight that can be carried around the house and garden easily. The tripod I use is a Manfrotto 190B Professional Tripod with a Manfrotto 329 RC4 tripod head. This tripod head can carry up to 8 kilograms.

Whenever I want to observe only for a short period, I put the tripod outside and mount the Sky Window (with binoculars already attached) onto the tripod. I am observing within a minute! That's what I call "convenience". When I want to observe for a few hours or all night, I prefer using a table. I can have my books, sky atlas or printed maps, pencils, sketchbook, and red flashlight right beside the Sky Window.

Locating objects with the Sky Window is easy. It works the same as with a telescope. You "point" the Sky Window at a bright star in the area you want to observe, using the mirror. From there, star hop to your destination, using a star map. You have to know your way around the night sky, but if you know how to star hop with your telescope, star hopping with binoculars wont be a problem.

skywindow + vixen
Vixen 20x80 and Sky Window on table

skywindow and vixen
Vixen 20x80 and Sky Window on tripod

The binoculars

During the first year I observed using a pair of Bresser 7x50 binoculars. This binocular has a field of view of 6.1 degrees. A few months ago I bought Vixen 15x80 binoculars with a field of view of 3.5 degrees. The Bresser and Vixen both have sufficient eye-relief for people who, like me, suffer from astigmatism, and have to observe wearing glasses. According to Trico Machine Products, the Sky Window can be used with binoculars that have a maximum aperture of 80mm and/or a magnification of 20x. Binoculars with apertures larger than 80mm are too wide for the mirror. Binoculars with a magnification of more than 20x cannot be used with the Sky Window because of the quality of the mirror. Up to 20x the mirror produces images without degradation. Most binoculars are attached to the Sky Window using the 1/4-20 standard tripod port on the binocular focus spindle. For some other, like my 15x80 Vixen, you can order adapters. 

binocular Vixen
Vixen 15x80

binocular vixen
Vixen 15x80 and Bresser 7x50 FOV

I use the 7x50 Bresser for observing wide star fields and really big clusters. The 15x80 is used to observe the more compact clusters, wide double stars and other deep sky objects. They both provide wide field of views, which my 8-inch f/10 telescope cannot provide, due to its very limited field of view (46.5’ maximum). Take a look at the image below to see the difference in field of view of the 6.1 degree Bresser (outer circle), the 3.5 degree Vixen (middle circle), and the 46.5 arc minutes of the 32mm Televue plossl eyepiece, used in an 8-inch f/10 telescope (inner circle).

Field of view binocular vixen
Open cluster Collinder 70 (Belt of Orion) with three circles representing the different FOV's
Image genrated with SkyTools 2 by Capella Soft

The Sky Window on it’s first night out

On the night the Sky Window saw first light, I put it with the 7x50 Bresser binoculars already attached, on a simple garden table. I started at 8 pm. Cygnus was in the zenith. After a while I looked at my watch and to my amazement it was 00.30 am already. I had been observing the area within and around the summer triangle (Cynus, Altair, Vega) for more than four hours on end! I saw many beautiful objects like Collinder 399 (The Coathanger), 61 Cygni, Omicron 1 and 2 Cygni, the Cygnus star clouds, M39, Epsilon Lyrae and many more. The most beautiful part of the Cygnus Star clouds I observed that night was the area between Gamma Cygni and Albireo. There is no telescope that can beat 7x50 binoculars with it's wide field of view on these wide star fields. However, the most important thing on that first night out with the Sky window was: after more than four hours of observing, I wasn’t tired at all and I did not feel any pain in the neck or back. I had to work next day, so I packed up for the night, but I could have gone on for hours!

Any drawbacks?

There might be two possible drawbacks for some people, the mirrored view and the loss of light caused by the mirror.

When using the Sky Window, the orientation of the image is different from what I see through my finder-scope or telescope, and it doesn’t match the orientation used in star atlases. However, I print my star charts with SkyTools 2 or TheSky for Macintosh. Both programs have the option of rotating and/or flipping the orientation of the star maps. This enables me to print star charts that have the same orientation as the image I see when looking through my telescope or binoculars and Sky window. So for me, the “mirrored” view isn’t a problem. You get used to the different orientation very quickly.

Trico Machine Products claims that the mirror they use for the Sky Window reflects about 95% of the light that falls onto it. I can live with that, even if it would be 85% or 90%. My telescope, an 8-inch Klevtzov-Cassegrain has a central obstruction of 35% and a star diagonal, which probably reflects only between 90 and 95% of the light. How much light and contrast do I lose with this telescope? I never had a problem with that. So is this loss of light caused by the Sky Window mirror really a drawback? Not for me.

Some final thoughts on the Sky Window

After trying to observe the night sky with binoculars in almost every possible way, for me, the binocular mirror mount proved to be the best. Since I own the Sky Window, I use my binoculars more often than the telescope. The telescope takes me 15 to 20 minutes to setup, and weighs about 33 kilograms, the Sky Window and binoculars are setup within 1 minute and only weigh about 5 kilograms! Together, they offer sharp, rock-solid views of the night-sky. Because you will be observing with two eyes, it is easier to detect the colours of stars.

Besides all that, the Sky Window turns your binoculars into a great observing tool for the whole family. People from all ages can enjoy the view of the night sky from a very comfortable position, sitting on a chair and looking down into binoculars. They don’t have to lie down, crane their neck skyward, hold heavy binoculars in front of their eyes; they just sit down and enjoy the view. Because of the relatively low weight and the quick and easy setup and breakdown, the Sky Window, could even become your favourite travel-scope.

I would like to end this article by telling you that I know only three other users of the Sky Window personally, but they are all as enthusiastic about it as I am (and they have no back problems!). It’s up to you to decide if this mount is something for you.

Skywindow on Mount
The Sky Window and Vixen 15x80 binoculars mounted on the Manfrotto head and tripod

For more information on the Sky Window, visit the homepage of Trico Machine Products. There you will find a Sky and Telescope test report, comments from Sky Window owners, but also more information and more pictures. You can also contact Trico Machine Products for any questions you have. Their customer service is very good. And last but not least, join the Sky Windows user forum, a discussion group for Sky Window users. Here you can get in contact with Sky Window users around the world, read about their experiences and ask all your questions.

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