News from NEAF - new Televue line of eyepieces

[vhuang168]

Can't understand all this waiting for a telescope. What do they do? Wait for the lens to grow and mature? its totally unforgiveable for a company to make their customers wait so long for a product. In 2-3 years, new products that are better and cheaper could have appeared as is the possible case now. I think such companies deserve to lose their customers...

This is no mass produced scope. Its about as hand made as they come. Not only that, it is about as perfect as they come as well. Mechanically and optically, everything is superbly designed and manufactured. Think the ultimate Bentley/Rolls Royce for telescopes and that would be about right.

Each lens objective is ground, polished and checked by 1 man only. Roland Christen himself. No one else touches the lens. He is also the only one to assemble and align the lens cells. The assembly and alignment takes on average 5 hrs per cell. That is why the wait is so long.

As for losing customers.. far from it. They actually have more people sign on the wait list because of it. New products that are better do come about. AP doesn't produce the same old scopes since day 1. Their scopes have evolved also, the wait list just gets migrated over to the new scopes. So the list for the 155 gets moved to the list for the 160 when the 160 replaced the 155 etc. Imagine, the wait for the 160 is now about 7 years.

And I don't think objectives can be cheaply made either. All the new chinese 'APOs' are a good example. While it is a good value for a good scope, it does not reach APO status IMHO. There still color on very bright objects esp in/out of focus. AP, TMB, SV and a few other companies are producing APOs with no color what so ever. There have been some tests that have shown that they have acheived the CA correction not from good optic design but from increasing the f ratio. They did that by vignetting the main objective. So the 100mm f9 is closer to a 90+mm f10+.

So even though they use FPL53 which is the same material used by AP and other top tier manufacturers, the tolerances are not as tight and the design is not fine tuned. All the top optic designers have said this, its not really what the low disperion element is made from that really counts, its what its mated to that matters more.

I've rambled on enough... there was a segment in a TV show here called 'Made in America' and they showcased AP. I'll see if the link is still up if you guys are interested.

Vincent

[vhuang168]

Here's the link to the show.

http://24.237.160.4/AstroPhysics/

Vincent

[jermng]

There have been some tests that have shown that they have acheived the CA correction not from good optic design but from increasing the f ratio. They did that by vignetting the main objective. So the 100mm f9 is closer to a 90+mm f10+.

Hi could you point us to a source/link? Thanks!

[anat]

That was a hot discussion in the Refractors yahoo group stirred up by Markus Ludes (as usual)

[vhuang168]

I'll see if I can dig up the thread. Its been a while.

Vincent

[Tachyon]

Yes, and unfortunately a thread in another forum that discussed this topic turned into China bashing...

[weixing]

Hi,

There still color on very bright objects esp in/out of focus.

What do you mean?? You mean the CA is still visible when in focus at very bright object?? Moon??

There have been some tests that have shown that they have acheived the CA correction not from good optic design but from increasing the f ratio.

IMHO, there is nothing wrong in increasing f ratio to get to the status of APO. Whether the manufacturer use better optics design, better material or just increase the f ratio, as long as the final result meet APO status, it is still an APO scope... If the f ratio is so long that it doesn't sell, that's the manufacturer problem.

They did that by vignetting the main objective. So the 100mm f9 is closer to a 90+mm f10+.

Oh... If they sell the scope as 100mm f9, but in fact it is 90+mm f10+, then that's not very healthy...

Have a nice day.

[vhuang168]

Hi,

There still color on very bright objects esp in/out of focus.

What do you mean?? You mean the CA is still visible when in focus at very bright object?? Moon??

Sorry, I meant inside and outside of being in focus.

Vincent

[weixing]

Hi,

Sorry, I meant inside and outside of being in focus.

Oh... then I think that's not a problem la... because no one is going to observe at inside and outside of the focus... what really importance is how it performs in focus.

Have a nice day.