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Refractors: Vintage vs. Modern

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#76 Bomber Bob

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Posted 13 January 2017 - 12:36 PM

Aluminum swarf isn't good for optics.

 

Good point.  I try to work only on hardware in my shed, and do the optics stuff in my man cave.


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#77 solarviewer

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Posted 13 January 2017 - 12:44 PM

Man cave, that would be so nice, sigh! My wife keeps telling me I can have my own man cave any time I want. All I have to do is clean out, fix up, repair, and remodel the basement. Needless to say, that was several years ago and I still don't have my man cave. Every time I start, something important comes up. I think I'll start this weekend as I really want a good place for making a telescope with my granddaughter and that's the best motivation in the world. :-)


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#78 paulymo

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Posted 13 January 2017 - 01:04 PM

"...and I could not discern the hose clamp up in the nest."

 

Clearly you have some ATM squirrels in your backyard working on a mounting issue.  Can't wait for the day you do your squirrel nest test and find them pointing a scope right back at you!


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#79 rayden68

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Posted 13 January 2017 - 01:20 PM

Well they had me scratching my head for a moment, its a steel hose clamp like the kind you would use for dryer exhaust hoses. Squirrel nest curb appeal maybe?


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#80 AstroKerr

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Posted 04 November 2018 - 11:46 AM

Man cave, that would be so nice, sigh! My wife keeps telling me I can have my own man cave any time I want. All I have to do is clean out, fix up, repair, and remodel the basement. 

 

You might want to get that in writing, witnessed.  There's a good chance of that becoming a Gal Cave when you've finished. My 'CNC' room quickly became 'Kiln & Welding' room once Sybil finished her latest bout of college - "I'm back, Basil, you'll just have to adapt - move those noisy things out, I need some space..."  Yes, dear...

 

Love is: Doing as requested by Tuesday.


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#81 Defenderslideguitar

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Posted 04 November 2018 - 08:16 PM

Thanks for re booting reviving this older thread     Folks like me enjoy the read and education......

 

My mancave used to be called the pool table room    then it became  my daughter's high school friends hang out place  then it became  the college kids are home hang out room .....  now  she's  married and living 4 miles away     it is my man cave music room violin  and stringed instrument repair shop and telescope display room....and slide out our  sliding doors to the patio and my window of opportunity  eventually the planets other objects enter this narrow window of opportunity     and  life is good

I am lucky to have it   this old pool table room   and my lovely wife who tolerates the husband with the hobbies

HobbyHubby?

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Edited by Defenderslideguitar, 04 November 2018 - 10:43 PM.

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#82 AstroKerr

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Posted 04 November 2018 - 11:15 PM

So it's true then - they do exist?  There've been rumors - a lady in Madagascar in the 1800's near Antisiranana, a wife in Wunna Theiddhi Ward, Naypyitaw, Burma (Myanmar, now), Scottish lass in the Outer Hebrides, Scotland... a few more over the years - two or three confirmed sightings. You lucky, lucky fellow...

<sigh>

What's it like - to live paradisially like that? 


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#83 Paul Sweeney

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Posted 05 November 2018 - 06:45 AM

Hi all,

 

interesting old thread. To me, the main difference in the classic vs new comes from the numbers. I found a Chinese supplier of 60mm lenses who could supply 2500 telescopes per month. Agaist that, there was recently a thread in Refractors that said Zeiss produced about 10000 refractors in total. Which one took the time to figure their lenses correctly? Old scopes have generally better lenses because there were opticians instead of machines at work.


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#84 Defenderslideguitar

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Posted 05 November 2018 - 10:54 AM

Paul  

Yes   I have to agree  Zeiss quality come from or comes from.... materials used, design and  old world craftsmanship  when quality over quantity matters

 

you get what you pay for

 

Meanwhile this is similar to Fender guitars of Fullerton California   when Leo Fender   got ill and possibly  thought he might be  dying he sold out to CBS in 1965    Fender went from making a few guitars each week to many times that    and the quality albeit still quite good  was not the same...

 

There is some good quality stuff made for the mass market today I would think at a certain price point that it is okay        but   older craftsmanship is so appealing.... just saying

 

Barry


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#85 roscoe

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Posted 05 November 2018 - 02:23 PM

That's the first time in my whole life I've seen a cue-stick with a finder scope, and you've got a whole bunch of them!!


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#86 luxo II

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Posted 06 November 2018 - 11:21 PM

William Dawes once remarked that it requires magnification around 80X per inch to clearly resolve double stars at the Dawes limit.

Even with modern scopes I can’t recall many capable of that much magnification for any practical purpose.

To me this confirms that some of the scopes used in the 18th and 19th century must have had exquisite objectives - by that I mean strehl above 0.96 - despite the relatively primitive eyepieces and the lack of AR coatings.

Equally I am sure there were many cheap scopes that are optically inferior, much as is the case today.

Edited by luxo II, 07 November 2018 - 12:07 AM.


#87 droid

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Posted 07 November 2018 - 04:21 AM

Taken into account.....most of the old school telescopes, were sold in brick and mortar stores, were the assembly line, if you will, products of they're time. I'm sure tasco imported possibly thousands ,or more, of these scopes.

 

If you can find one in Walmart now, Christmas time usually, they're  on plastic or flimsy mounts, mostly plastic, and the 1.25 equivalent of the worst eye pieces ever made.

 

So apples to apples , there is no comparison. 

 

To get a modern version as good or better than the imports of the day, you have to go on line. whether new or used, careful shopping will find you one as good or better, but even that isn't guaranteed.

 

The scopes from between the late 70s all the way to probably the mid 1990s were well, the " Christmas trash telescopes" and one of the reasons a lot of folks bailed on amateur astronomy, in my opinion.,

 

Orion and Celestron, as well as Meade sell some very decent entry level scopes now ,but usually direct from them either through second party sellers, such as Amazon, or even Cloudy Nights.



#88 luxo II

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Posted 07 November 2018 - 07:24 AM

Orion and Celestron, as well as Meade sell some very decent entry level scopes now

Not sure if anyone else has noticed this...

The Celestron and Meade websites do not state any quantitative optical quality that could be inferred as a warranty or guarantee. Nowhere do they suggest "diffraction limited" nor a quantified criterion such as PV better than ¼ wave.

Instead their websites are chock full of soft waffle.

Statistics from a test lab suggest the Celstron products are averaging ⅓ wave. That's the average, and it means 50% of scopes shipped are worse than that. Meade, ½ wave.

That's not "decent". Cheap perhaps, but it’s also crap.

Edited by luxo II, 07 November 2018 - 07:52 AM.


#89 terraclarke

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Posted 08 November 2018 - 11:13 AM

Statistics from a test lab suggest the Celstron products are averaging ⅓ wave. That's the average, and it means 50% of scopes shipped are worse than that. Meade, ½ wave.
 

Actually, if it is indeed the AVERAGE, statistics do NOT say that 50% are worse. The Median would tell you that, not the mean (average). It could be that just a few are very bad, but many are above ‘average’ to produce a 1/3 wave mean. In statistics, it’s always important to keep your measures of central tendency straight.


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#90 Wildetelescope

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Posted 09 November 2018 - 07:32 PM

My interest in classic achromatic refractors was spurred by a visit to the classic scope booth at NEAF a couple years back.  I was surprised at the image quality the long focus achromatic gave.  Have since acquired an excellent 80 mm f15 TOWA and a pretty darn good 60 mm f11 sears, that round out my refractor collection.  Can’t say I have look through many of the modern long focus achromats, but I prefer the view through the towa to the one I got with my old Orion 80 mm eon(which was not at all bad either).   Just a matter of personal taste, not a statement on merits of different scope designs.  Each scope has its own character, and I usually enjoy myself no matter what the design is.  

 

There are are certainly good values to be had, with patience and a bit of knowledge.  This forum is an excellent resource to get the latter.  As someone else said, just look at Bomber Bob’s signature list;-)

 

cheers!

 

jmd 


Edited by Wildetelescope, 09 November 2018 - 07:33 PM.


#91 Jim Curry

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Posted 10 November 2018 - 07:32 AM

Actually, if it is indeed the AVERAGE, statistics do NOT say that 50% are worse. The Median would tell you that, not the mean (average). It could be that just a few are very bad, but many are above ‘average’ to produce a 1/3 wave mean. In statistics, it’s always important to keep your measures of central tendency straight.

Thank you for that clarification, doctor (PhD)


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