Where to find refractor objective lenses

Though it's still in the thought stages, I'm kicking around the idea
of a constructing a folded refractor with a fixed eyepiece for mainly
RFT use (my 9.25" SCT and 90mm Mak cover the (semi-)light bucket/high
power/planetary and really quick look categories pretty well) with a
binoviewer. I know the import lenses from China are decent for the
most part and think a low power scope based around a 120mm f8.3 or f/5
or, even better, 150mm f8 or f/5 in conjunction with the binoviewer
(and, if necessary, a focal reducer) would make for a killer setup. I
know I can get a new or used OTA and use the lens out of that or could
luck into a used lens alone, but I'd also like to have a US source for
the lenses alone new. I know ApogeeInc used to carry them, but I'm
getting nothing on their website, so, does anyone else carry them?
Thanks in advance.

On Feb 6, 12:27 am, " wrote:
Though it's still in the thought stages, I'm kicking around the idea
of a constructing a folded refractor with a fixed eyepiece for mainly
RFT use

Why would you want a folded (long f.l.) refractor for RF use? Why not
just BUY a rich field scope?
William Optics sells 80mm fluorite lenses separately, about $400 or
so.
For achromats, Sky Instruments sells a variety.

On Feb 6, 1:17 pm, "Rich" wrote:
On Feb 6, 12:27 am, " wrote:

Though it's still in the thought stages, I'm kicking around the idea
of a constructing a folded refractor with a fixed eyepiece for mainly
RFT use

Why would you want a folded (long f.l.) refractor for RF use? Why not
just BUY a rich field scope?
William Optics sells 80mm fluorite lenses separately, about $400 or
so.
For achromats, Sky Instruments sells a variety.

Thanks for the info, I'll check out Sky Instruments. As to why build
one as I described instead of just buying an already built OTA, well,
there are several reasons. For one, with my desire to use a
binoviewer, most refractor OTAs would require either additional
auxiliary lenses to bring it to focus, which would increase the
effective focal length making it less of an RFT, especially when
limited to 1 1/4 eyepieces in the binoviewer. If I take the lens and
build it myself, I'll have control over just where things come to a
focus... and with a focal reducer, I'd be able to get RFT views even
with a longer focal length lens. For another, I'd like to construct
it so that the eyepiece end doesn't move for ease of viewing, not
something I could really accomplish with a pre-made OTA. Cost is a
factor, as well... as inexpensive as the chinese achromat OTAs are,
buying only the lens itself is a cheaper route and I can put some of
the savings to other important things, such as a good focuser,
especially since I already have suitable flat mirrors so won't have to
worry about that expense. And, perhaps the most important reason...
the sheer joy and satisfaction of building my own, especially
something slightly unusual like this. I may not be enough of a do-it-
yourselfer to be ready to grind my own lenses, but I do enjoy building
a worthwhile scope myself, even if I purchase the optics.

On Feb 6, 3:54 pm, " wrote:
On Feb 6, 1:17 pm, "Rich" wrote:

On Feb 6, 12:27 am, " wrote:

Though it's still in the thought stages, I'm kicking around the idea
of a constructing a folded refractor with a fixed eyepiece for mainly
RFT use

Why would you want a folded (long f.l.) refractor for RF use? Why not
just BUY a rich field scope?
William Optics sells 80mm fluorite lenses separately, about $400 or
so.
For achromats, Sky Instruments sells a variety.

Thanks for the info, I'll check out Sky Instruments. As to why build
one as I described instead of just buying an already built OTA, well,
there are several reasons.

Sorry, I didn't word it right. I can fully understand building one,
just not a folded one.
Building scopes is great fun and today with so many good parts
available, you can assemble stuff to your liking.

Though it's still in the thought stages, I'm kicking around the idea
of a constructing a folded refractor with a fixed eyepiece for mainly
RFT use

Jaegers is back in business. I think the son of the original guy.
The lenses are cosmetic seconds from Zeiss so I've heard.
I have used them and they are good lenses. Not apochromats,
but good standard achromatic objectives.

http://ajaegers.com/acrolens.htm

Clif

On Feb 6, 12:27 am, " wrote:

Though it's still in the thought stages, I'm kicking around the idea
of a constructing a folded refractor with a fixed eyepiece for mainly
RFT use ... in conjunction with a binoviewer

Sounds like an entertaining project. But for true rich-field viewing,
binoviewers are inherently inferior to true binoculars, because
for any given exit pupil, a binoviewer only feeds half as much
light to your eyes. And given how cheap giant binos are these
days, it's a pretty fair bet that you'll end up spending more on
this project than you would to get equal or better results from
an off-the-shelf product.

Put another way, a 150mm objective with a binoviewer provides
the same amount of light as normal 100mm binoculars, but the
binoculars allow you to go to lower magnifications without
exceeding your own eyes' pupils.

- Tony Flanders

wrote:
Though it's still in the thought stages, I'm kicking around the idea
of a constructing a folded refractor with a fixed eyepiece for mainly
RFT use


Jaegers is back in business. I think the son of the original guy.
The lenses are cosmetic seconds from Zeiss so I've heard.
I have used them and they are good lenses. Not apochromats,
but good standard achromatic objectives.

http://ajaegers.com/acrolens.htm

Clif


Not exactly what I'd call cheap, though. $195 for an 80mm objective? Not
the Jaegers that I remember.

On Feb 9, 8:23 am, starburst wrote:
wrote:
Though it's still in the thought stages, I'm kicking around the idea
of a constructing a folded refractor with a fixed eyepiece for mainly
RFT use

Jaegers is back in business. I think the son of the original guy.
The lenses are cosmetic seconds from Zeiss so I've heard.
I have used them and they are good lenses. Not apochromats,
but good standard achromatic objectives.

http://ajaegers.com/acrolens.htm

Clif

Not exactly what I'd call cheap, though. $195 for an 80mm objective? Not
the Jaegers that I remember.

You can buy a decent 80mm in a cell for about $50.00.
http://www.antaresoptical.com/atm.htm

Rich wrote:

On Feb 6, 12:27 am, " wrote:
Though it's still in the thought stages, I'm kicking around the idea
of a constructing a folded refractor with a fixed eyepiece for mainly
RFT use

Why would you want a folded (long f.l.) refractor for RF use? Why not
just BUY a rich field scope?

Because these guys always have some "theory" in mind and
have their minds made up, being experts. I should have thought
by now you would everyone is an expert. It takes a truck load of
experts to warm up a whole planet.





William Optics sells 80mm fluorite lenses separately, about $400 or
so.
For achromats, Sky Instruments sells a variety.

On Feb 7, 8:50 am, wrote:
On Feb 6, 12:27 am, " wrote:

Though it's still in the thought stages, I'm kicking around the idea
of a constructing a folded refractor with a fixed eyepiece for mainly
RFT use ... in conjunction with a binoviewer

Sounds like an entertaining project. But for true rich-field viewing,
binoviewers are inherently inferior to true binoculars, because
for any given exit pupil, a binoviewer only feeds half as much
light to your eyes. And given how cheap giant binos are these
days, it's a pretty fair bet that you'll end up spending more on
this project than you would to get equal or better results from
an off-the-shelf product.

One thing I can't stand with cheap binos are the eyepieces. Lousy
edge definition,
coupled with objectives that are too fast. The experience isn't all
that great.