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Pentax Telescopes & Mounts

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#176 Nippon

Nippon

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Posted 05 August 2022 - 11:10 PM

I will add anothers informations regarding the pentax 100mm series design for complet steveP post as i have the two versions of this series. SteveP has fully right, construction is completely different between the Pentax 100 and Pentax 100ED, no chrome on the ED series only; black anonized aluminium but it stays like this from the begining until the end the series as i have got a friends who has a late ( after 1984) version of the Pentax 100 Achro and it was also fully chrome

 

I do not have the official explanation but maybe there are two ways:

 

- First cost killing, pentax will make a compromise for winning money on this scope as producing ED glass at high level precision must cost more money especcially at begining ED period and if you look at the selling price, ED version difference cost was not so much than "normal" version.

 

- Second is regarding balancing scope and overall weight, ED glass is more heavy than normal glass so if you ad the chrome focuser from achromat who is really heavy you create an unbalancing and heavy scope and we do not forgot that's only 100mm scope.

 

Anyway this scope family was very good, regarding the 4" achromat version it is probably the best 4" that i have test.

 

Pictures of this two scope.

Are you talking about the chrome versus black drawtube? If so I may have a third theory. I had a Celestron Firstscope 80 back in the late 80s and a friend had a Celestron SPC80. The optical tubes were identical except the Firstscope had a brushed aluminum drawtube and the SPC 80 had a chrome drawtube. I reasoned at the time since the Alt/Az mounted Firstscope would be more likely to see some daytime use it had a dull brushed drawtube finish to keep glare out of the users' eyes.


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