Apo Lens Re-centering tools

Learning that doublet apo with steeper curves that matches triplet
in color correction has more potential for decentering. I think I'll
keep my triplet and re center the lens myself. The reason I can't
send my TMB triplet to the manufacturer is because I have to
spend huge on shipment (back and forth half a world away),
recentering charges (which runs into hundreds of dollars), and
when it'd be reshipped to me, I have to pay 50% taxes in my
country so I'd be spending more than $1000 total (and not
to mention the possibility of it getting decentered again in
its trip back to me as shipment workers sometimes just toss package
up the air).

That said. I'm willing to spend $500 on buying tools that can
enable me to recenter the TMB triplet myself (It fell to the
ground from 1 meter above when I put the luggage case in a
big rock at an angle). So where do I begin. What intruments
must I need? Such as Ronchi, Laser aligner, Lens distance
spacer, etc. Who among you have recentered a lens on your
own? I presume the lens cell has a spacer guide so I don't
need to know what is the distance between the lenses.
Recentering the elements with a common axis would be
enough.

Because I travel a lot with the triplet put in the airline
compartment. There would be many more days when it
would get decentered from unusually big shock. So I want
to learn to recenter it myself. If anyone can recommend a book
on fixing apo lenses and recenter. I'd greatly appreciate it too.
Thanks.

opti

Learning that doublet apo with steeper curves that matches triplet
in color correction has more potential for decentering. I think I'll
keep my triplet and re center the lens myself. The reason I can't
send my TMB triplet to the manufacturer is because I have to
spend huge on shipment (back and forth half a world away),
recentering charges (which runs into hundreds of dollars), and
when it'd be reshipped to me, I have to pay 50% taxes in my
country so I'd be spending more than $1000 total (and not
to mention the possibility of it getting decentered again in
its trip back to me as shipment workers sometimes just toss package
up the air).


Where are you coming from?

If you are living in Europe, send it to Markus - Germany.
If you are living in the USA, ask Thomas back!

You should never have to pay again for import!

In any other cases, ask a local TMB dealer. Don't do it yourself!


Erick





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(optidud) wrote in message . com...
Learning that doublet apo with steeper curves that matches triplet
in color correction has more potential for decentering. I think I'll
keep my triplet and re center the lens myself. The reason I can't
send my TMB triplet to the manufacturer is because I have to
spend huge on shipment (back and forth half a world away),
recentering charges (which runs into hundreds of dollars), and
when it'd be reshipped to me, I have to pay 50% taxes in my
country so I'd be spending more than $1000 total (and not
to mention the possibility of it getting decentered again in
its trip back to me as shipment workers sometimes just toss package
up the air).

That said. I'm willing to spend $500 on buying tools that can
enable me to recenter the TMB triplet myself (It fell to the
ground from 1 meter above when I put the luggage case in a
big rock at an angle). So where do I begin. What intruments
must I need? Such as Ronchi, Laser aligner, Lens distance
spacer, etc. Who among you have recentered a lens on your
own? I presume the lens cell has a spacer guide so I don't
need to know what is the distance between the lenses.
Recentering the elements with a common axis would be
enough.

Because I travel a lot with the triplet put in the airline
compartment. There would be many more days when it
would get decentered from unusually big shock. So I want
to learn to recenter it myself. If anyone can recommend a book
on fixing apo lenses and recenter. I'd greatly appreciate it too.
Thanks.

opti

The best instruments a

1. good high pwer eyepiece
2. screw driver (or allen wrench screw)
3. Not very distant star-like source (30-50n away).

See which lenses can be moved (which ones have their centering scres.
The best to not tweak the inner lens made of very fragile ED glass.

You always need to move the lens in the direction of the coma
(or) and lateral color.

Without experience this is purely trial-error process. However if
you are patient enough, you will reach the success earlier or later.

Good luck.

V.D.

What intruments
must I need? Such as Ronchi, Laser aligner, Lens distance
spacer, etc.

You need a triplet apo lens centering tool, of course. You'll need either the
air sapced or oil spaced version depending which type of lens set you own. Be
sure to get the one with the laser lens centering chesire collimator already
built in. Much easier to recenter and test if you don't have to keep switching
back and forth. As far as spacers go, I believe most manufacturers of apos use
strips of tin foil for spacing. I've heard that Reynolds foil is the most
consistent for thickness.


rat
~( );

email: remove 'et' from .com(et) in above email address

I believe most manufacturers of apos use strips of tin foil for spacing

Where can one buy tin foil? I thought all you could get now is aluminum.

Roland Christen

http://www.alfa.com/alf/laboratory_c..._suppliers.htm
put tin foil in the search box
they have even platinum foil, that would go well with the AP scopes ;-)

David

Chris1011 wrote:

I believe most manufacturers of apos use strips of tin foil for spacing

Where can one buy tin foil? I thought all you could get now is aluminum.

Roland Christen

http://www.alfa.com/alf/laboratory_c..._suppliers.htm
put tin foil in the search box
they have even platinum foil, that would go well with the AP scopes ;-)

David

Try ESPI (Electronic Space Materials International) I have purchased quite a
bit of stuff from them (including Platinium sheet.) Good service, friendly and
they have a huge selection.

http://www.espi-metals.com/

As far as Tin goes, they have tin foil in thicknesses ranging from 0.001" to
0.009" in grades from 4N to 6N (99.99% to 99.9999)

They also have Thulium, Terbium, Tellurium, Samarium, Praseodymium and just
about any thing else one can thing of....

jon

Useless troll... I suppose he actually decentered his imaginary
TMB lens while mountain biking with it, which was his big troll
last time he got the wild urge to write his stupid posts.

Leela

Remember the old Televue ads that showed a Ranger mounted on a bicycle where
the air pump is usually mounted? I wonder if anyone besides optidud ever did
that.

rat
~( );

email: remove 'et' from .com(et) in above email address

On Wed, 23 Jul 2003 15:27:47 -0700, "Bob May"
wrote:

How do you know that the lens needs adjusting? Centering the lenses in the
cell is going to be fun if there are adjustments for that. I'll note that
all of the lenses should not have any wedge in them so there should be no
problems in that regard.

That is funny.
-Rich

Can we be sure that terrorism and WMD will join together?
If we are wrong, we will have destroyed a threat that, at
its least is responsible for inhuman carnage and suffering.
That is something I am confident history will forgive.
But if our critics are wrong and we do not act, then we will
have hesitated in face of this menace, when we should
have given leadership. That is something history will not forgive.
-Tony Blair

chris1011 wrote

Where can one buy tin foil? I thought all you could get now is aluminum.

It can be scavenged from tin cans. Recycling centers are good places to check.

You can also scrape the TiN coating off of some drills and milling cutters.


H.