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I have a cheap telescope that I use for bird watching and occasional moon viewing.

I just purchased a 15mm eyepiece.

Is there a table of some sort that would tell me what the various eyepieces are doing numerically ?

102 mm aperture
500 mm focal length
F 5

10mm, 18mm and 25mm
Eye pieces also.
Are the numbers on the eye pieces power number?





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Posts: 55461 | Location: Henry County , Il | Registered: February 10, 2004Reply With QuoteReport This Post
Little ray
of sunshine
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https://skyandtelescope.org/as...copes-magnification/

This tells all about eyepieces and telescopes.

Those are not magnifications, power is a function of the focal length of the eyepiece and the focal length of the objective lens (telescope itself).

Read the article, I'd just repeat it, because I can't do better.




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Posts: 53499 | Location: Texas | Registered: February 10, 2004Reply With QuoteReport This Post
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Posts: 3190 | Location: PNW | Registered: November 16, 2012Reply With QuoteReport This Post
goodheart
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Here are the power (X) figures for the four eyepieces:

10 mm 50 X
15 mm 33 X
18 mm 28 X
25 mm 20 X

These are all pretty low-power eyepieces. If you want more magnification, you need to get shorter focal length eyepieces, e.g. 6 mm, or get a Barlow lens that will increase the magnification (or both). With more magnification you get less light, and more susceptibility to mount movement and to atmospheric turbulence. 102 mm objective size is fine for magnifications quite a bit higher than these eyepieces, assuming the glass is reasonably good. But trying for, say, 250-300 power would probably not give you a very usable image in most circumstances.


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Posts: 18796 | Location: One hop from Paradise | Registered: July 27, 2004Reply With QuoteReport This Post
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Very helpful folks.
Pats on the back, it's appreciated.
Sjtill
Those powers helped a bunch.

I forgot to mention a 2x Barlow , I have as well.

Means a lot that you took the time to respond





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Posts: 55461 | Location: Henry County , Il | Registered: February 10, 2004Reply With QuoteReport This Post
goodheart
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Have you tried the moon and Jupiter yet? We just missed the conjunction of Venus and Jupiter this last weekend, which was in the early morning hours.


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Posts: 18796 | Location: One hop from Paradise | Registered: July 27, 2004Reply With QuoteReport This Post
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Still cold wet and rainy here on a regular basis
( No. West Illinois)

Forgot to mention overcast





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Posts: 55461 | Location: Henry County , Il | Registered: February 10, 2004Reply With QuoteReport This Post
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quote:
Originally posted by bendable:
I have a cheap telescope that I use for bird watching and occasional moon viewing.


I want to use my telescope for bird watching or even long distance target shooting but I need to buy an erecting prism. Since you bird watch, what erecting prism are you using ?
 
Posts: 3190 | Location: PNW | Registered: November 16, 2012Reply With QuoteReport This Post
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My scope came with 2) eye pieces, a 45 degree adapter erector.

My bird watching distance's here in Illinois are almost always within 100 yds .
In Arizona
It was out too 200 on a regular basis.

I call it a cheap scope and it was ($300.00 )
But with the tripod, head and additional eyepieces ,
The whole shebang is at about $850.00 , out of pocket.

I've looked through other people's leica's, Bushnell's and Swarovski's

And am very happy with mine by comparison.
It's not compact by any means but I consider it portable,
As I can carry the whole mess in one trip.

This message has been edited. Last edited by: bendable,





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Posts: 55461 | Location: Henry County , Il | Registered: February 10, 2004Reply With QuoteReport This Post
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