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Trico Machine Products "Sky Window"

Trico Machine Products "Sky Window"

by Don Pensack (don@supergo.com)

What is it?

It is the a reflecting mirror mount for the astronomical use of binoculars. Because of it's size, the largest binoculars that can use the mount will be about 70-80mm aperture. No binoculars within the usual sizes will pose a weight problem for the mount, but it does point out that a heavier or stiffer tripod will be steadier.

Where do you buy it?

From Trico Machine Products at 216-662-4194 or on the web at http://www.tricomachine.com/skywindow

How much does it cost?

Current retail is $229.95, tripod adapter included (but not tripod). There may be extra charges for mounting arms that accept large binoculars.

What are the advantages over the parallelogram binocular mounts that you see at star parties?

It's compact and easily carried and stored. Broken-down, you could carry the mount on a plane in a briefcase. It doesn't require counter-weights. You can sit while observing, looking down as if through a microscope. By tilting the mirror, you can view from behind the zenith to below the horizon. By rotating the tripod or by moving the mount (if used by itself on a table top such as a patio table), you can scan the entire visible sky from a comfortable, never-varying, chair height. You never have to crane your neck to look up. You never have to stand up to view. Everybody looking through the eyepieces will see the same view. It's less expensive than most parallelogram binoculars mounts. It fits just about all photo tripods with the provided tripod mounting plate attached.
It holds the binoculars so steady the faintest stars visible will be seen.

What are its disadvantages?

In a humid environment, the first surface mirror will dew up, though a hair dryer will free it from dew again and, thanks to the low power used in binoculars, not introduce obvious thermal distortions.

There is no tube around the first-surface mirror, so it will collect dust. Since the mount will be used at low powers, cleaning the mirror with a blower syringe will work well until the small dust cannot be blown off. When and if the mirror gets too dirty (several years?), cleaning it like you would clean a telescope mirror will be called for. I won't go into cleaning methods, here, but it should be easier to clean than a telescope mirror because minor sleeks and scratches are unlikely to be visible at all due to the wide fields and low powers used.

It views the image upside down, like a telescope, so it is not usable for terrestrial observations.

It reveals the optical inaccuracies of your binoculars brutally and without mercy.

I am now on set number 5 (of 10x50 binoculars), and it is obvious they will have to be replaced too. If you have a set of binoculars that doesn't form a good image, you'd never notice it hand-holding them because the beating of your heart and the unsteadiness of your arms tend to smear the star images anyway. Five minutes on the Sky Window mount and you will know the truth about your binoculars. If you have bad astigmatism on one side, or a poor focus mechanism, or poor edge correction in the field-of-view, it will be almost immediately apparent. So it could get expensive unless you deal with companies that have a liberal return policy (or you have excellent binoculars). I currently have 2 pairs of 10x50 binoculars on hand, both with wide fields, yet one is considerably better than the other (it's the cheaper pair, too). This was not apparent hand-holding them.

Last, though in theory you actually are losing light gathering ability because of the reflected light loss, in practice the dead-steady mounting adds at least a magnitude to the faintest stars seen.

Personal Impressions:

This is simply the best way to use binoculars for astronomical observations. Why this didn't simply obsolete all other binoculars' mounts instantly upon appearing in the market, I don't know. It's so easy to use it takes all of 10 seconds to figure it out. By a simple glance at the reflected sky under the mounted binoculars, and a minor adjustment to the tilt of the mirror, it is easy to come close enough to centering a star that that star will be within the field of view. Some users add a Telrad or red-dot finder to their binoculars to make it easy to center the object they search. Other users attach a SkyPointer laser to point the way. Whereas these finders can help, I did not find a finder necessary at all.

It's just that easy to use.

How to Find Objects

The easiest way to find an object is this: figure out on which side of the sky the object you seek is located. Rotate the Sky Window to point toward that quadrant of the sky. Move your chair to behind the mount and sit down. Look up to see where the nearest star to your object is, and rotate the Sky Window until it points toward a vertical line going up from the horizon to that star. Look at the reflected image of the sky by sighting at the sky underneath your binoculars, but parallel to them. Move the mirror's tilt with the knobs on the sides, or by holding the corners of the mirror, until you see your target star appear in the mirror. Continue moving the mirror until the target star is about in the center of the mirror. When you look through your binoculars, the star may not be centered, but in the wide fields common to binoculars, it will be in the field. Move the tilt of the mirror and rotate the Sky Window on the tripod to control altitude and azimuth to center the star. Then, scan to your object. I'm sorry if I make this seem complicated. Just be aware this is really what you do when you look for an object when you are hand-holding the binoculars---you look at the sky over or under your binoculars to make sure they're pointed in the right direction. It's the tilt of the mirror and the rotation of the tripod (or the mount if it's on a table top) that replaces your arm movements. It's a LOT easier than it sounds. By the end of my first night with them, I was finding objects as easily as an experienced dob user (except I move a mirror instead of the scope).

And what views!!!! I never knew a pair of binoculars could be a serious observer's tool until I saw the Andromeda galaxy, with its 2 closer companions, spanning almost the entirety of a 4.5-degree field. Or saw the dark nebulae that surround the small star cloud M24 in Sagittarius and traced their paths out of the field of view. In a dark site, a simple pair of 50mm binoculars will see more than a somewhat larger scope will see in the city-and this from an instrument that can be carried in the front seat of your car and used on the trunk or roof of your car if you don't want to carry a tripod (or chair-I don't know why you would want to do so, but the sky Window can be used on a tripod at standing height)

Recommended for everyone who uses binoculars for astronomical observing.

Don Pensack

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