Meade Instruments TMB Optical TMB-130 - Manual

Signature Signature Signature Signature Signature Series Series Series Series Series
TMB Optical
TMB-130
Thomas M. Back
Thank you and congratulations on your purchase of
this TMB Optical TMB-130 130mm f/7 ED apochromatic
triplet refractor. Its optical and mechanical quality will give
you many years of observing enjoyment.
TELESCOPE MOUNTS
Your new TMB-130 is usable with many different types
of telescope mounts. A suitably sturdy altazimuth mount is
a good choice for most purely visual observing. An altazi-
muth mount is typically light in weight, easy to set up, and
is relatively low-priced. Just be sure that the mount is ca-
pable of handling the scope’s weight (which will be well
over 20 pounds after adding mounting rings, diagonal, eye-
piece, etc.)
A high quality German equatorial mount would be an
excellent choice for both visual and imaging purposes. The
very stable German-type equatorial mount can be driven
in both right ascension and declination for photography
and CCD imaging, as well as for uninterrupted visual ob-
serving. The quality of your images will not only depend
on the optical quality of your telescope, but your local con-
ditions (the seeing and how dark your site is), the tracking
accuracy of your mount, your imaging equipment, and your
guiding and image processing techniques.
TUBE RINGS
No tube mounting rings are supplied with your TMB
refractor. However, well-machined 142mm TMB hinged
split rings are available from your telescope dealer.
FOCUSER
Your TMB-130 has a dual speed Starlight Instruments
Feather Touch Model FTF3545 rack-and-pinion focuser.
This ultra-premium focuser has a long travel 3.5” diam-
eter drawtube for non-vignetted astrophotography with
medium format film cameras and very large chip CCD
cameras. The drawtube ends in a 2” accessory adapter with
a non-marring soft brass compression ring eyepiece holder
that will not damage the barrels of your 2” eyepieces and
accessories. This adapter allows visual use with 2” star
diagonals and eyepieces, plus imaging with 35mm film
cameras and 2” barrel large format CCD cameras.
The 2” accessory adapter is secured to the focuser draw-
tube by three recessed hex-head screws. Undoing these
allows you to remove the supplied 2” adapter and replace
it with a custom-made Feather Touch adapter for medium
format (Pentax 6 x 7) film photography using A-P photo-
graphic accessories. Please contact Starlight Instruments
directly at (847) 985-9595 for any specialized adapters
you may need in this regard.
The supplied 2” to 1.25” accessory adapter is designed
for visual use with 1.25” star diagonals and accessories,
plus imaging with standard format CCD, webcam, and
35mm adapters. This adapter also uses a non-marring soft
brass compression ring to hold your 1.25” star diagonals
and accessories in place. The barrel of this adapter is
threaded to accept standard 2” filters and has a slight in-
ward taper at the top. The taper engages the compression
ring of the 2” adapter to prevent the 1.25” adapter from
slipping out of the focuser, should the 2” adapter’s thumb-
screw accidentally loosen during use.
Features of the Focuser’s Right Side
Coarse
focus
knob
2” accessory
adapter
Fine
focus
knob
Focusing scale
on drawtube
(1 on each side)
2” accessory
lock knob
(1 of 2)
Brass
compression
ring
Focuser
rotation
handle
(1 of 3)
Combined drawtube
tension/lock knob
under focuser
Focuser
rotation angle
locking ring
Coarse focus knob
Finder bracket
mounting holes
Focuser rotation
handle (1 of 3)
2”
accessory
adapter
1.25” accessory adapter
Features of the Focuser’s Left Side
2” accessory
lock knob
(1 of 2)
Brass
compression
rings
Screws
connecting
2” adapter
to drawtube
(2 of 3)
the shorter of the pair is the lock screw that holds the proper
collimation after adjustment. Be sure to adjust only one
set of collimation screws at a time. Loosen the lock screws
before attempting to turn the collimating screws. Make only
small changes at a time (turning the collimating screw only
a fraction of a turn and checking to see the results before
turning further).
When you finish adjusting the collimating screws, be
sure to snug down all lock screws to hold the correct colli-
mation. Do not over-tighten the lock screws, but make sure
they are firmly in place. Once collimation is complete, your
objective lens will be on the same optical axis as the eye-
piece, camera, or CCD, and you will obtain the best pos-
sible optical performance.
The other method of collimation is to examine a first
or second magnitude star image at high power at night af-
ter the scope has reached thermal equilibrium. This colli-
mation method requires an equatorially-mounted scope and
a motor drive to keep the star image centered while you
adjust the collimation screws. It is generally a more diffi-
cult and time-consuming collimation method than using a
Cheshire eyepiece, as you are working with a small and
droppable Allen wrench in the dark and are at the mercy of
changing seeing conditions.
Be sure not to choose a closely-spaced binary star as
your test star. Do not use a star diagonal when collimating,
as you may be attempting to correct a problem in the di-
agonal, rather than in the telescope. Adjust the push-pull
collimation screws until the star images are tight and round,
and the first and second diffraction rings are uniform in
their intensity all the way around the Airy disk.
THE STAR TEST
We strive to make the best apochromatic optical sys-
tems available. You may find your lens may not test “per-
fect” during an extended and stringently-graded “star test,”
particularly if the scope has not fully reached thermal equi-
librium before the test. This is not an indication of a poor
optic. It is rather due to the test star’s complex wavefront
of light that is being constantly changed by our living at-
mosphere as seeing conditions vary from minute to minute,
from second to second.
No optic is perfect and likewise, under a detailed and
extended star test, every telescope optic will show some
error. The sensitivity of the star test under perfect condi-
tions is 1/20th wave P-V on the wavefront for third order
aberrations, and 1/60th wave for sharp (fifth order) aber-
rations. It is highly unlikely that even the most ardent ob-
server can see errors of this small a magnitude, even under
very good seeing conditions (which is when the atmosphere
typically presents a 1/4th wave P-V wavefront to the tele-
scope and eye).
Something else to consider in star-testing refractors:
the change in spherical aberration with a change in wave-
length. This is called “spherochromatism” and is found in
the wavefront of all refractors. What this means is that as
the lens is tested in the longer (red) wavelengths, the lens
becomes “under-corrected,” and in the shorter wavelengths
(blue), the lens becomes “over-corrected.” These overlap-
ping corrections at different wavelengths change the star
test pattern from perfection.
So, while star tests are interesting and useful, most ob-
servers spend their nights enjoying the heavens, not just
examining points of light. We feel that the proof of optical
excellence is in the observing, not just in the testing.
All TMB objectives are corrected at the peak visual
wavelength, which is centered at around 560nm in the
green-yellow portion of the visual spectrum. The eye sees
over 80% of the visual detail at this wavelength, and it is
the proper correction at this visual peak that makes the
difference between just a good objective, and a superb one.
We design and figure our lenses for the best possible
wavefront at the green-yellow wavelengths, to give you
the sharpest images and highest contrast possible.
A FINAL WORD
We thank you for your purchase of this TMB-130. We
believe that this apochromatic refractor will outperform
any other telescope type, inch for inch, and is the most
trouble-free telescope that you can buy. Its versatility in
visual, photographic, and CCD work is unmatched. With a
little care, this fine apochromatic refractor will last you a
lifetime. Please enjoy the wonders of the night sky!
SOME BRIEF SPECIFICATIONS
Aperture ................................................... 130mm (5.1”)
Focal Length ....................................................... 910mm
Focal Ratio .................................................................. f/7
Objective Type ........ air-spaced ED triplet apochromatic
Optical coatings ................................... fully multicoated
Resolving Power (Dawes’ Limit) ......... 0.89 arc seconds
Visual Limiting Magnitude .................................... 13.1
Light Grasp Versus the Eye ................................... 345x
Focuser .......... FeatherTouch #FTF3545 rack and pinion
with dual-speed and 11:1 reduction ratio fine focus;
2” and 1.25” compression ring eyepiece holders;
360° rotating camera angle adjuster
Focuser Travel ........................................ 4.33” (110mm)
Tube Diameter ................................. 142mm (5.6”) o. d.
Tube Length (lens shade retracted) ...... 28.75” (730mm)
Tube Length (lens shade extended) ....... 34.5” (876mm)
Optical Tube Weight ............................ 18.7 lbs. (8.5 kg)
TMB Optical, P.O. Box 44331, Cleveland, OH 44144 (216) 524-1107
E-mail: [email protected]
© 2007 by TMB Optical
The collimation screws
(one pair of three)
The collimation screw
(taller)
The lock screw
(shorter)
The lens cell
Lens
T
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