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Posts Made By: John Biretta

April 11, 2002 08:08 AM Forum: Equipment Talk

Mirror re-coating

Posted By John Biretta

Opinions on enhanced coatings are mixed. They usually
cost 3x more than standard coating. Some argue that
they scatter more light and hence a poorer for planets
(which are bright anyway). Glass-pushers argue they
damage the figure unless carefully done.

I think (personally) that it generally makes sense
to buy a diagonal with an enhanced coating, but
cost of enhanced-coating a big primary is probably
not worth it.

The scuttle-butt is that most outfits that do
enhanced coatings won't bother with amateurs any more,
or if they do, the turnaround times are very
unpredictable. The guys with the equipment aren't
making money off odd amateur mirrors -- they just do it
to be nice. I've sometimes waited 3+ months
on an enhanced coating (after promise of 30 days).
I'm sure if you wanted to pay full-up industrial
prices they'd be more than happy to do it tomorrow
and Fed-X it back. But if you have to ask what it
costs ....

Relevant coating companies these days seem to be
http://www.majestic-coatings.com/ (Al)
http://www.clausing.com (Al, enhanced, etc)
http://home.covad.net/~alcoat/ (Al)
http://members.aol.com/lenses/ (Al, enhanced)

April 20, 2002 10:01 PM Forum: Equipment Talk

Which company ships scopes safely?

Posted By John Biretta

Well, here's my USPS international telescope shipping
horror story:

Shipped a scope from Netherlands to Baltimore, Maryland,
USA via overnight Express Mail. Big bucks for scope and
shipping. After two days, no scope. Checked the
tracking -- there is entry at my local post office on
day it should have been delivered, followed by delivery
next day to a zip code in FLORIDA. I went to local
Post Office and asked if they had seen my package.
They said they could not talk to me, and that the
Shipper in the Netherlands could file an insurance claim
for the package after 30 days. I was completely
stone-walled by these people. The shipper in
Netherlands was no more helpful ... "The scopes in the
USA; its not my problem. Good luck."

I spent the next three weeks playing detective and
making phone calls, and finally figured out what
happened. One of my neighbors said someone couple
streets over had just moved to Florida. I got this
person's new address, called him, and indeed the USPS
had delivered a huge package a couple weeks ago. He
still had it; no one had come to take it back.

Even at this point USPS was nearly impossible to deal
with. I finally got my Regional Supervisor for Express
Mail to call the Supervisor at the post office in
Florida where the scope was delivered. At last I
got some action ... some wonderful USPS staffer in
Florida went and got the scope, and over-nighted it
to me at no added cost. Finally got my scope after 4 weeks!

The bottom line, is that USPS was EXTREMELY hard to
deal with once things went wrong. No one would talk to
me, and no one cared. They even had trouble
figuring out what the proper claim process and which
forms to use. Even worse, the burden of filing
the claim is on the shipper (person purchasing the
insurance), who in this case had his cash, shipped the
scope, and was done with the transaction.

Sorry for being long-winded.... My advice is only to
buy from reputable international dealer, who will stay
involved until you have your scope and are "satisfied."
Don't use USPS. Use some other company that does
international shipping as its bread and butter.
Good luck. - John B.

April 20, 2002 10:31 PM Forum: Equipment Talk

Halographic lasers ?

Posted By John Biretta

Yes, I've got one. They are much more versatile.
Examples:

(1) You can easily tell if your diagonal is centered
under the focusser, by looking at the pattern of
dots inside the tube opposite the focusser.

(2) It is easy to find the center of the primary
mirror, if you don't have the center marked. Just center
the dot pattern around the periphery of the mirror.

(3) You tell how well the system is collimated by
looking at the pattern of dots coming out the
front of the scope. If any of the optics are off-center
(tube, primary, seconday) its easy to tell.

These EZ-collimators are also nice, though they only
have single dot. Sometimes I switch between hologram
collimator and EZ-collimator during collimation.

- John B.

April 27, 2002 12:47 AM Forum: Equipment Talk

TV-76 and TV-85 Scopes

Posted By John Biretta

I've used both. Unless you need extreme portability
(backpacking, birding) I'd go with the larger TV85
for the slightly higher resolution. TV85 also accepts
standard 95mm threaded filters, so you can protect that
nice lens from dust / dew in extreme conditions.

April 27, 2002 09:25 PM Forum: Equipment Talk

NGF-S: Comments?

Posted By John Biretta

I use it for fine focus during visual observing on my
C9.25. Works great. I still do coarse focus with the
scope's moving mirror system.

May 7, 2002 08:53 PM Forum: Equipment Talk

Parfocalizing rings

Posted By John Biretta

Go to Home Depot / Lowes / True Value. Hit the
plumbing department and get some rubber O-rings.
They come in lots of sizes. Get some that fit
tightly over the 2" tube.

May 10, 2002 04:50 PM Forum: Equipment Talk

MN61 Mirror Problem

Posted By John Biretta

Hi. I think if the bad region is only 1" across
and is near the center of the mirror (partially
hidden by the secondary mirror), it probably cannot
explain the poor views of Jupiter and Saturn.
I suspect the poor views might be related to something
else, like air currents inside the tube
(due to being slightly warmer than outside air), or
turbulence in the atmosphere (poor seeing).
I suppose the problem could also be that the scope is
grossly out of collimation -- that would cause
"coma" aberration, which resembles a flare on
one side of the image.

A 1" bad region of the mirror is only about 3
percent of the light, so its not going to kill
the scope. It would just reduce contrast a tiny
bit -- so slight that only an expert would
notice anything.

Getting back to the bad place on the mirror:
Is it possible for you to tell if light goes
through the bad spot? Do you have easy access
to the back of the mirror? If you
shine a flashlight at the back of the mirror and
look in the front of the scope, can you see if the
light goes right through the bad spot? If so,
then the coating is shot, and the mirror would
need to be removed and re-coated. Probably
cost $50 and someones time to remove and re-install
mirror.

If the mirror is still opaque at the bad area, it
probably just needs to be carefully cleaned. There
are probably lots of places on WWW explaining how
to do this.

I think Orion has a service department, and also sell
these scopes. I would check with them first.
Also check with ITE; they might be able to help.

Best of luck, - John B.

May 14, 2002 04:22 AM Forum: Equipment Talk

Need help with C-9.25 focuser

Posted By John Biretta

I am not familiar with this exact micrometer counting
system on the C9.25, but if it is like other digital
micrometer counters, the black lever will be a friction
lock that prevents rotation of the shaft. In one position
the shaft turns freely, in the other position the shaft
is locked.

June 6, 2002 09:54 PM Forum: Equipment Talk

Binoviewer and Deepsky

Posted By John Biretta

I agree you want a big scope if you are
going to use binoviewer on deepsky. I find
bino does help increase contrast against
sky background. The eye seems better at
pulling out faint stuff when both eyes are
used ... though of course each eye is getting
less light, so there is a trade-off. Few
sights can compare to M13 in a bino with
18" scope... FWIW I've got the Zeiss/AP.

June 9, 2002 07:42 PM Forum: Equipment Talk

Orion vs Discovery

Posted By John Biretta

I've got a recent Orion XT-6 and am very happy with it.
Optics are superb. I think the bigger F/ number will
tend to give better images, but the lower F/ number
will be more portable -- depends where your priorities
are.