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Posts Made By: John Biretta

May 18, 2003 09:55 PM Forum: Equipment Talk

Tele Vue at the NEAF

Posted By John Biretta

The new products announced included:

Nagler 20mm Type 5. Its a 2" only, 6 element,
12mm eyerelief. "Available June 2003"

Theres a new snap-on focus lever for the
refractors. Its about 6" long rod with a
ball on the end. I tried it, works nicely.
Lets you fine-tune the focus.

Other stuff you probably knew about:
Panoptic 41mm
Nagler Type 6 in 2.5, 3.5, 11mm
Bandmate OIII filter
TV NP127 refractor

There was the usual NEAF sale on "blems"
and discontinued TeleVue stuff. There were
lots of Plossls and Panoptics and a few
of the Naglers going a great prices, but
alot of us had those models already. No
31 Nagler blems.

June 13, 2003 02:53 PM Forum: Equipment Talk

Burned on an Astromart deal

Posted By John Biretta
Just about every refractor I've bought used has shown
up with a bent focusser shaft and out of collimation.
These are very common problems.

June 27, 2003 08:02 AM Forum: Equipment Talk

Illuminating My Finder Scope

Posted By John Biretta
I think the hard part will be keeping the LED out
of direct view. Otherwise there will be a very
bright and distracting bunch of light. Usually
the LED is placed very near the crosshairs, and
illuminates them from a recess or hole in the
side of the tube. That way theres no direct
light path from the LED to the eye.

If the LED is up near the objective lens, it will
be really hard to keep it out of direct view.
And brightness of the crosshairs may also be a
problem if the LED is far up the tube, so it is
a doubly bad situation.

Probably best location is in the side of the tube
just foward (toward the objective lens) of the
crosshairs. That way the mounting of the crosshairs
will help block direct light.

Any LED will be bright enough; it doesn't take much
if its done right.

June 28, 2003 03:46 PM Forum: Equipment Talk

Looking for a little advice

Posted By John Biretta
TV 2x is the best way to go. Its very sharp, and
there is no light loss or darkening around the field
edges (i.e. no vignetting). Only down side is its
rather long and the 1.25" barrel will stick way out of
most 1.25" diagonals -- a little non-asthetic but
works great.

Celestron 2x Ultima (and the Orion Shorty Plus) are
best of the short Barlows; very sharp. Used with
say a 25mm or 32mm Plossl there will be some darkening
around the field edge; there is some trade-off for
shortness. Don't get me wrong though, I've to two and
think they're great for high-power viewing.

Meade 140 "APO": I used one briefly in a TV85
refractor, and was surprised how much false color
there was; really bad. Maybe I just had a dud.
Just because there are three pieces of glass does
not make it APO.

June 29, 2003 06:57 PM Forum: Equipment Talk

Life expectancy of a lens pen?

Posted By John Biretta
I've noticed they seem to work best in the first couple
weeks after opening it. But I have a couple that are
2+ years old, and I still use them on "cheap" optics
and they still work OK.

I think the larger concern is getting dirt/grit on the
cleaning pad which then might scratch anything else
cleaned with it. I try to use them only after blowing off
the optics and cleaning with fluid / cotton balls /
q-tips to get any remaining smudges. If one was to
use it exclusively for cleaning, then you might want
to be more careful and throw it out after a couple
uses.

I'd be interested to hear what others experience is....

Does anyone know exactly how they work? It seems to me
there is some sort of cleaning agent in the cap --
either a fine absorbant (carbon?) powder, or a
micro-encapsulated solvent.

July 4, 2003 07:21 PM Forum: Equipment Talk

Outta My League

Posted By John Biretta
In my experience the most critical aspect is to get
all three pads the same thickness. The thickness itself
is a little less important.

July 7, 2003 09:03 PM Forum: Equipment Talk

TeleVue Nagler Zoom 3-6mm/Pro or Con?

Posted By John Biretta
I'm fairly happy with mine. Its convenient to have
only one planetary eyepiece instead of 4+. I just
keep it in my favorite scope ready to observe.
Only bug I've found is that you sometimes end up
rotating the eyepiece instead of zooming, unless the
lock screw in your 1.25" adapter (or diagonal)
is quite tight. The eyerelief is tight, in case
that bothers you. I'm used to orthos, so its OK.

The there's my observing buddy who has a love-hate
relationship with this eyepiece. I think hes
bought and sold 3 of them. The eyerelief thing
seems to bother him more than it does me.

July 12, 2003 03:31 AM Forum: Equipment Talk

Bino scope long baseline?

Posted By John Biretta
If you could combine the two light beams,
say with a beam splitter prism or mirror,
and keep the optical paths identical to a
small fraction of a wave, what you would see
is the usual approx 1 arcsecond seeing
disk. But it would also have bright and dark
stripes on it corresponding to about 0.3
arcseconds, which is your 12" resolution.

What can you do with this? Not too much
if you are just looking with the eye.
If you looked at a double star separated by
about the same amount (0.3 arcsec) the stripes
would go away and come back as you rotated
the 12" baseline.

Try puting a mask with two holes in front of
your scope, and see what happens.

July 13, 2003 06:08 AM Forum: Equipment Talk

CGE 1400 Purchase

Posted By John Biretta

I got to look through two of these C14 OTAs at
Winter Star Party. I was very impressed; they
gave a nearby 10" $40K APO a good run for its
money. Planetary detail was really nice on Jupiter
and Saturn. Go for it, I say.

August 7, 2003 01:53 AM Forum: Equipment Talk

Synta Refractor Collimation

Posted By John Biretta
One of my Syntas has a similar creeping collimation
issue. A quick fix thats worked so far is to
place the scope pointing straight up, loosen the
front retaining ring from the lens, give it a
couple gentle raps all around the side of the
lens cell, and then tighten the retaining ring
again. I think what is happening is that the
lens elements creep around in the cell (either
separate or move sideways), and this seems to get
them back in the right place again.

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