[CT Birds] OT: Scope recommendations

Al Collins aecollins83 at hotmail.com
Wed Dec 13 10:48:20 EST 2017


James,

When I asked a similar question 30 years ago. a veteran CT birder told me “Gear doesn’t matter; the person using the gear matters.” My experience since then has convinced me that this is largely true.

Whatever gear you use will be VASTLY better than anything that was available to Peterson, Wilson, Steller or Darwin. For that matter, it will be better than anything available 30 years ago. Would it be better to have a premium scope? Probably. Will it provide any practical advantage to your ability to see and identify birds? Possibly in darker conditions at dawn or dusk, possibly at the extremes of distance.

Regarding the scopes you saw on Amazon, I have a few thoughts.

First, the objective lens is a doublet 80mm achromat, two separate lenses that focus light slightly differently, minimizing the color “halo” that will appear in single lenses. They are made in China, at one of several optical manufacturers using automated lens grinding equipment from Japan. You can see some of them here:

https://www.alibaba.com/showroom/telescope-lens-achromatic.html

Most lenses in mid- to low-end scopes come from one of these companies. The lenses are very consistent from unit-to-unit. The glass itself is manufactured in China to typical specs (N-BK7 for lenses, N-BK4 for prisms). I have bought three lens pairs direct from a manufacturer over the past year for astronomy projects and have been happy with them.

The high-end premium scopes use triplet apochromatic lenses, with three different pieces instead of two, and have virtually no color halos.

Lens coatings can vary widely; from what I can see on the Amazon listing for the GoSky it has pale violet / blue anti-reflective coatings, which address the primary problem of flare. Premium scope lenses will have more complex, selective coatings that prioritize certain parts of the wavelength, resulting in better contrast in real-world conditions. Some low-end scopes have deep orange, green or blue coatings. These are cosmetic and detrimental to the overall viewing, so avoid any that have this.

The eyepiece is a likely source of problems. A zoom eyepiece will have 5 - 7 individual lenses. Design and assembly are much more complex and error-prone. Lower-end eyepieces will usually suffer at magnification above about 40x, and by losing clarity at the edges of the field of view.  I’d expect that at this price point you will find these limitations.

Durability is another concern. The magnesium-aluminum housing is similar to premium scopes, but the focusing mechanism, hinges etc. will be less durable. If you run your car over a Kowa or Swarovski scope it will probably be fine (don’t ask me how I know this). If you run over the GoSky you’ll probably need a new one.

If it were me, I’d get one of these scopes and invest in a quality tripod, as was already mentioned in this thread. When it arrives, check it out. If it has dark coatings, is out of alignment, is unusable at lower magnifications or has other problems, return it and get your money back. If not, use it to go out and see birds until you find a good used one or win the lottery.

Al
________________________________
From: CTBirds <ctbirds-bounces at lists.ctbirding.org> on behalf of Patrice via CTBirds <ctbirds at lists.ctbirding.org>
Sent: Wednesday, December 13, 2017 8:16 AM
To: ctbirds at lists.ctbirding.org
Subject: [CT Birds] OT: Scope recommendations

A great place to find info & products to buy (including pre-used) is Cape
May Bird Observatory. Check their website & go to FeatherEDGE optics -
'buyers guide" for  tips & "optics" & "tripods" for products for sale. They
check all product performance before selling. Also a great place to visit
in person.
Patrice Favreau
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