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Found Old EPs-Any Good?

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#1 Guest_**DONOTDELETE**_*

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Posted 19 June 2004 - 12:08 PM

In the basement we have an old 60mm Galileo refractor. Just today I decided to look at it's EPs, wondering if they would go along with my XT10. There's a 20mm and a 4mm. Here are the pics:

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I don't think they have coatings. I was gonna try them out tonight though.

---Slickmm---

#2 lighttrap

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Posted 19 June 2004 - 12:12 PM

I wouldn't be surprised if those aren't .965" rather than 1.25".

#3 jwaldo

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Posted 19 June 2004 - 12:22 PM

They appear to both be Huygens, an old, outdated design with every abberation you cann imagine, so no, probably not good :(

#4 Guest_**DONOTDELETE**_*

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Posted 19 June 2004 - 12:31 PM

The scope itself was one from BJ's or Target, something like that.

---Slickmm---

#5 matt

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Posted 19 June 2004 - 05:00 PM

May I add that the Huygens is also notable for its very narrow fov (in the 30° range!). Charles Huygens is forgiven because he actually invented the eyepiece design business, and there was very little competition from Televue and Takahashi back then.
Some people say, though, that the H is very good for solar projection, so as you can get nada resale value on astromart for this thing, you could as well keep it for solar observing. The Huygens design is actually the simplest possible - two lenses, one converging and one diverging, which create an achromatic lens; just like an achro objective on a refractor. Good news, you can see stars with them. Bad news (or good news for eyepiece designers and salesmen), it works only on axis - whenever your go across the fov (which is narrow anyway), you're in trouble. Add to that that the manufacture of such an eyepiece is rarely done to very high standards.

As for the "SR", it's a Symetrical Ramsden, another primitive design favored by department store telescope designers, which could serve proudly as a dust plug on your focuser.

#6 Greg K.

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Posted 22 June 2004 - 12:50 AM

Well, did you try them?

#7 erik

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Posted 22 June 2004 - 09:50 AM

even today, many department store scopes come with hyugens. the 4mm is probably like looking through a pinhole...

#8 LivingNDixie

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Posted 22 June 2004 - 10:49 AM

Yeah those look like great solar projection eyepieces :)

#9 Guest_**DONOTDELETE**_*

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Posted 22 June 2004 - 05:35 PM

I had some experience with Huygens ep’s that came with my very first scope. Before I was reading this topic I was so lucky to forget all about them! Back then, as a novice with scopes, they almost caused me to change hobby. I still find it a pity that some suppliers and shops are still delivering them whit fist scopes.
Only the bigger focal lengths >15mm will give reasonable views.
Bonzo

#10 erik

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Posted 22 June 2004 - 06:47 PM

...and even the longer f/lengths hyugens are like looking through a plossl with a thick brown film over the lens elements... :(

#11 John Jarosz

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Posted 22 June 2004 - 07:34 PM

Hey, I just used my Ramsden eyepiece from 1966. I think it cost $3.00. I used it for a new adaptor barrel for a .965 eyepiece. I threw the lenses away. So there! :waytogo:

john


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