60 replies to this topic

[Mike Spooner]

First let me say, Congratulations on your new scope! I’m sure will serve you well for a long time to come.  

 

Frequently the subject of “NASA” glass comes up when we are talking about pre ed AP’s from the 80’s. It has always been my understanding by the time the Starfires appeared in 1986, “NASA” glass was no longer being used.   

Here is some great information from Thomas Back in the late 90’s     https://groups.googl...r/c/KKnD2Vc_hcQ

 

Here is a shot of a 6” F9 lens cell with the NASA glass.  

Thanks for sharing the link! Brings back memories from the sci.astro.amateur days. 

Thomas included references to the S&T and TM 28. Also somewhere I had read that Roland made some of the NASA glass available to a few interested folks. Somewhere in my shop I have an 8” blank supposedly from the batch though I’ve never verified the glass. If my ambition ever recovers from retirement  maybe I’ll revisit a possible long f.l. lens to see how good it would be. Since my purchase happened decades ago, perhaps my dreams have mellowed. I still recall some lovely observing through several 6” AP scopes and the stunning performance is worth the price of admission, IMHO. 
 

Mike Spooner

[Scott99]

I am tempted lol. I think I'll just keep the AP 6" for a while and save my pennies.

It's classic scope!  Many of them were made, everbody wanted to order the 6-inch in the 80's because AP's prices were so low.  I never felt the need to upgrade until I had enough $$ to get one of AP's ED scopes.

[zjc26138]

The goal is to save for a larger ap scope or a tec160-180 lol

[Phillip Creed]

The goal is to save for a larger ap scope or a tec160-180 lol

Given the resultant focal lengths, though, it's far more economical to image with another scope design.  The dedicated reducer only drops the TEC160 to 1,000mm FL @ f/6.2.  You'll still have comparable speed, much more focal length and a much more compact package with a reduced 8" SCT.

Plus you can through a reduced C8 onto an AM5 and move the entire assembly in one go if you setup somewhere remote.

A TEC 160/180 would definitive look more elegant and refined.  The "oomph" factor of seeing a giant refractor in an observatory is unmatched.

Clear Skies,

Phil

[zjc26138]

Given the resultant focal lengths, though, it's far more economical to image with another scope design.  The dedicated reducer only drops the TEC160 to 1,000mm FL @ f/6.2.  You'll still have comparable speed, much more focal length and a much more compact package with a reduced 8" SCT.

Plus you can through a reduced C8 onto an AM5 and move the entire assembly in one go if you setup somewhere remote.

A TEC 160/180 would definitive look more elegant and refined.  The "oomph" factor of seeing a giant refractor in an observatory is unmatched.

Clear Skies,

Phil

 

Yeah the TEC160 or similar sized refractor would be mainly for visual and the occasional imaging. I have an AT60ED for widefield and a Celestron 8" sct for galaxies and PN's (though its severly out of collimation at the moment and I haven't had the time to fix it)

[Scott99]

Given the resultant focal lengths, though, it's far more economical to image with another scope design.  The dedicated reducer only drops the TEC160 to 1,000mm FL @ f/6.2.  You'll still have comparable speed, much more focal length and a much more compact package with a reduced 8" SCT.

ewwww!  Yucky
 

[zjc26138]

I will certainly attempt some deep sky imaging with this scope.  Might as well.

 

I do have a C8 for imaging too, but its badly out of collimation and my attempts thus far have not worked.

[RNapo]

Hi, the Astro-Physics APOs made in the mid 1990's and on used FPL-53 for the middle element. 

One exception is the first Stowaways that used fluorite as the middle element. When you shine a green laser at the objective the middle element seems to be missing. 

 A Lucky Ducky telescope.  :-)

 

I believe the NASA glass was used in the 1980s. 

 

[SilverLitz]

I believe the latest Stowaway and 110GTX uses FCD-100 instead of FPL-53.

[RNapo]

Hi Gemini,

Interesting!  How is FCD-100 different from  FPL-53.

It's bin a few years since I got back on CN.

[RNapo]

Sorry, I should search the net first.

Amazing what you can find on the net.  :-)

Apparently FCS-100 is the optical equivalent of FPL-53 but made by Hoya.