DIY: velvet or velour inside SCT tube

Anyone been contrast-enhancing their SCT by adding velvet or velour on the
inside (naturally)
of their SCT tube ?
Experiencing any problems ?
How about disassembling the SCT, f.i .the correctorplate ?

FG

"Joda" wrote in message
k...
Anyone been contrast-enhancing their SCT by adding velvet or velour on the
inside (naturally)
of their SCT tube ?
Experiencing any problems ?
How about disassembling the SCT, f.i .the correctorplate ?

FG



Not sure about either.
Both can have light reflecting qualities.
Black felt may be your better choice.
jojo

"Joda" wrote in message
k...
Anyone been contrast-enhancing their SCT by adding velvet or velour on the
inside (naturally)
of their SCT tube ?
Experiencing any problems ?
How about disassembling the SCT, f.i .the correctorplate ?

FG

Been studying it. From what I have gleaned on the subject it is better to
use that protostar flocking paper as velour or velvet will shed. Saw a "flat
black" paint developed just for "flocking", can't remember the name and
haven't seen any reports on how well it works yet. Just looking at my SCT it
would seem easier to totally remove the tube and "work" on it rather than
try and do everything through the corrector end with the mirror still in the
tube. There was a site showing the flocking of an 11" Celestron,
dismantling, flocking, reassembly, good pictures and info. The owner said he
could really tell the difference, this however could be subjective, after
doing all that work you would sure want to see positive results. bg

Steve

"Joda" wrote in sci.astro.amateur:

Anyone been contrast-enhancing their SCT by adding velvet or velour on
the inside (naturally)
of their SCT tube ?
Experiencing any problems ?
How about disassembling the SCT, f.i .the correctorplate ?



I think (the) non-reflecting black paint inside is better than velvet or
velour, which will keep reflecting light.

Take care that you re-assemble the corrector plate in exactly the same
position as when it was assembled before. Most of the time there will be
small cork supports installed in the factory between teh plate and the
ring support in the tube.
These cork supports must be placed back in the same way. If so, mark both
the position of the cork supports as the position of the corrector plate.

--
CeeBee


Uxbridge: "By God, sir, I've lost my leg!"
Wellington: "By God, sir, so you have!"


Google CeeBee @ www.geocities.com/ceebee_2

You know, I've considered doing this for some time and did a bit of research
on it on the internet. It seems from most of the reports that the best
contrast gains came not from flocking the inside of the OTA, but from
flocking the inside of the baffle tube. If you look into it (or at least
into mine) it's pretty not-black. I have some flocking paper from Edmund,
which is black as anything (you can also get the same stuff sticky-backed
from McMAster), but I can't figure out a way to get it inside the little
tube, get it to stick, and have it be removeable. If anybody figures out a
good way, could you let me know? TIA - Chris


"Joda" wrote in message
k...
Anyone been contrast-enhancing their SCT by adding velvet or velour on the
inside (naturally)
of their SCT tube ?
Experiencing any problems ?
How about disassembling the SCT, f.i .the correctorplate ?

FG

"starburst" wrote:
| "Joda" wrote in message
| k...
| Anyone been contrast-enhancing their SCT by adding velvet or velour on the
| inside (naturally)
| of their SCT tube ?
| Experiencing any problems ?
| How about disassembling the SCT, f.i .the correctorplate ?
|
| You know, I've considered doing this for some time and did a bit of research
| on it on the internet. It seems from most of the reports that the best
| contrast gains came not from flocking the inside of the OTA, but from
| flocking the inside of the baffle tube. If you look into it (or at least
| into mine) it's pretty not-black. I have some flocking paper from Edmund,
| which is black as anything (you can also get the same stuff sticky-backed
| from McMAster), but I can't figure out a way to get it inside the little
| tube, get it to stick, and have it be removeable. If anybody figures out a
| good way, could you let me know? TIA - Chris

There's an old saying: "If it ain't broke don't fix it." :-)

If the inside wall of the baffle tube isn't smooth (e.g., it's ribbed) then
there's not much else you'll be able to do because it _is_ baffled (though
how well is another matter :-)

If the inside wall is smooth (as it was in my Apex 90), then there is
benefit gained by flocking it (as I did). Here's how I did it using
ProtoStar flocking paper.

Disassemble the OTA (or remove the rear cell) to gain easy access to the front
and back of the baffle tube.

Cut the flocking paper into strips about 1/4" wide; the actual width will
depend on the inside diameter of the baffle tube: measure it and cut n
strips approximately 1/4" wide such that the total width of n strips
equals the inside diameter of the baffle tube. The reason for (approx.)
1/4" is to facilitate handling; anthing wider will be tricky to apply.
The length of each strip should be about 1" longer than the tube.

Remove the backing from one strip of flocking paper and push it through
the tube; a long stick or drinking straw will be helpful. I positioned
the rear cell from my Apex 90 facing upwards so I could hold one end of
the strip and lower it into the tube. With about 1/2" of the strip
sticking out the front, press that end into place and at the other end
pull and twist the strip about 90 degrees so that when pressed down
there's a spiral; a wooden stick (or baton) can be used to press the
flocking paper along its entire length inside the tube. Repeat using
the remaining strips. Then gently slice the excess paper at each end
of the baffle tube using a razor or X-Acto (No.11) knife.

The reason for the spiral (quarter twist) is to "hide" the seam between
each adjacent strip. Tweezers may help position each strip especially
if the tube's diameter is small (as it is with the Apex 90). This is
tedious and I'd recommend cutting some extra strips to account for any
"gotchas". Might want to practice applying the strips inside a same-
length (as the baffle tube) piece of copper or plastic pipe to get a
feel for the technique.

Joda wrote:

Anyone been contrast-enhancing their SCT by adding velvet or velour on the
inside (naturally)
of their SCT tube ?
Experiencing any problems ?
How about disassembling the SCT, f.i .the correctorplate ?

FG

It doesn't matter if you coat the inside or the outside of the OTA with velvet
(or Velveeta), the increase in contrast will be the same. g
Zero.


But seriously, when you look up the back of an SCT (no eyepiece inserted), can
you see the interior of the main tube? If not, there's no point in flocking
it.

Clive.

That would imply that an interior surface made of mirrors (like a disco
ball) would also be okay if you can't see it. Correct?

JeffPo
http://www.mindspring.com/~jeffpo


gibbonsc wrote in message ...
But seriously, when you look up the back of an SCT (no eyepiece inserted),
can
you see the interior of the main tube? If not, there's no point in flocking
it.

Clive.

wrote in message
...

There's an old saying: "If it ain't broke don't fix it." :-)

If the inside wall of the baffle tube isn't smooth (e.g., it's ribbed)
then
there's not much else you'll be able to do because it _is_ baffled (though
how well is another matter :-)

If the inside wall is smooth (as it was in my Apex 90), then there is
benefit gained by flocking it (as I did). Here's how I did it using
ProtoStar flocking paper.

Disassemble the OTA (or remove the rear cell) to gain easy access to the
front
and back of the baffle tube.

Cut the flocking paper into strips about 1/4" wide; the actual width will
depend on the inside diameter of the baffle tube: measure it and cut n
strips approximately 1/4" wide such that the total width of n strips
equals the inside diameter of the baffle tube. The reason for (approx.)
1/4" is to facilitate handling; anthing wider will be tricky to apply.
The length of each strip should be about 1" longer than the tube.

Remove the backing from one strip of flocking paper and push it through
the tube; a long stick or drinking straw will be helpful. I positioned
the rear cell from my Apex 90 facing upwards so I could hold one end of
the strip and lower it into the tube. With about 1/2" of the strip
sticking out the front, press that end into place and at the other end
pull and twist the strip about 90 degrees so that when pressed down
there's a spiral; a wooden stick (or baton) can be used to press the
flocking paper along its entire length inside the tube. Repeat using
the remaining strips. Then gently slice the excess paper at each end
of the baffle tube using a razor or X-Acto (No.11) knife.

The reason for the spiral (quarter twist) is to "hide" the seam between
each adjacent strip. Tweezers may help position each strip especially
if the tube's diameter is small (as it is with the Apex 90). This is
tedious and I'd recommend cutting some extra strips to account for any
"gotchas". Might want to practice applying the strips inside a same-
length (as the baffle tube) piece of copper or plastic pipe to get a
feel for the technique.



Did it work, or could you tell the difference?

Steve

"Steve Little" wrote in message ...
wrote in message
...

There's an old saying: "If it ain't broke don't fix it." :-)

If the inside wall of the baffle tube isn't smooth (e.g., it's ribbed)
then
there's not much else you'll be able to do because it _is_ baffled (though
how well is another matter :-)

If the inside wall is smooth (as it was in my Apex 90), then there is
benefit gained by flocking it (as I did). Here's how I did it using
ProtoStar flocking paper.
[...]

Did it work, or could you tell the difference?

Yes, as I wrote: "benefit gained". :-)

The Apex 90 has an unbaffled baffle tube (oxymoron? :-) and flaring was a real
problem. Shining a flashlight into the front revealed the "leakage" paths into
the baffle tube (from around the secondary on the meniscus lens). Not only did
I flock the inside of the baffle tube I also flocked the entirety of the inside
of the OTA and the edges of the secondary.

The flocking definitely reduced the flaring but did not eliminate it entirely;
it's no longer as objectionable as in the "stock" condition. The original
flaring was a condition where the presense of an object NOT in the field of
view could be determined by "random" scattered light, readily noticeable with
the Moon and bright objects (Jupiter, Mars, Sirius, etc.)

At acute angles (less than, say, 10 degrees) even flocking paper will reflect.
Where it really shines (no pun :-) is inside the OTA opposite the focuser of a
Newt (though it'd be better to line the entirety of the inside esp. if the Newt
is unbaffled (as many are)).