TELESCOPE TAL-50K
TELESCOPE TAL-200K
Service manual
2
CONTENTS
Page
. General directions 3
2. Specifications 4
3. Standard equipment 5
4. Design and principle 9
5. Optical train 9
6. Telescope assembling
7. Order of operation 2
7.. Operation with telescope 2
7.2. Photographic observations 2
7.3. Telescope and atmospheric conditions 4
8. Maintenance 5
9. Rules of storage 6
0. Acceptance certificate 6
Supplement. Table of close stellar pairs for testing
image quality of the telescope 7
The telescope is subject to continuous development and improvement,
consequently it may incorporate minor changes in detail from the information
contained herein.
05.04
3
. GENERAL DIRECTIONS
ATTENTION!
Telescope TAL-150K, TAL-200K (hereinafter in the text referred to as «telescope») is not intended for direct visual observation of Sun at full operating
aperture. Because of high light intensity an image of Sun in focus of primary
mirror has a high temperature. To avoid on overheating of corrector it is recommended to avoid any direct observation of Sun disk.
One should remember that overheated corrector being in field of direct sunlight can be out of order or make a turbulent air torrents in telescope tube that
to reduce considerably a quality of image.
Also if it is necessary to leave a telescope out of door (for example, to dry it) one
should orient it so that the direct sunlight do not get into the optical system.
The telescope can operate normally at the ambient temperature from 30°C
to minus 30°C.
It is a precise powerful amateur astronomer telescope. It demands a careful
handling and certain knowledge in the field of astronomy. Only in this case user
will be fully satisfied.
When buying the telescope one should pay attention to the package safety
ensured by the seal of the manufacturing plant. After unsealing the case one
should check compliance of the complete set denoted in the list of enclosure.
Prior to using the telescope one gets acquainted with its handling and order of
operation.
4
2. SPECIFICATIONS
Name TAЛ-50K TAЛ-200K
Diameter of objective lens (operating aperture), mm 50 200
Focal length, mm 500 2000
Relative aperture :0 :0
Magnification and angle field of view (changeable):
- with the eyepiece f’=25 mm 60
x
80
x
40
"
30′
- with the eyepiece f’=0 mm 50
x
200
x
6′ 2′
- with the eyepiece f’=25 mm and Barlow lens 20
x
60
x
20′ 5 ′
- with the eyepiece f’=0 mm and Barlow lens 300
x
400
x
8′ 6 ′
Photographic angle field of view 40
′ 40′
(23.3mm) (23.3mm)
Screening of pupil in center 3% 2%
Resolution limit 0.8″ 0.6″
Pellucid capacity 2.8
m
3.4
m
Angular field of view of the finderscope 8° 7°
Magnification of the finderscope 6
x
8
x
Length tube, mm 425 550
Weight of the telescope, Kg 7.5
5
3. STANDARD EQUIPMENT
Name Qty
Telescope
Supply unit
Eyepiece of f’=25mm
Finderscope
Accessories and Parts
Eyepiece of f’=0 mm
Barlow lens
Reticle
Blind
Bushing
Adapter
Stopper
Housing
Service manual
6
Fig.. General view:
– telescope tube; 2 – finderscope; 3 – eyepiece
2 1
3
7
Fig. 2. Assemble of primary mirror together with eyepiece set:
– mirror; 2 – bushing; 3 – blending tube; 4 – screws;
5 – ball hinge; 6 – focusing mechanism; 7 – diagonal mirror; 8 – eyepiece;
9 – cover; 0 – back flange; – screw
1
2
3
11
10
8
9
7
6
54
8
Fig. 3. Corrector:
- mounting; 2 - reflecting lens; 3 - meniscus lens; 4 - padding ring
2
1
3
4
9
4. DESIGN AND PRINCIPLE
The tube 1 (fig.) is the basic part of the telescope, which embodies the optical
units such as a primary mirror, corrector, eyepiece set and finderscope.
The primary mirror 1 (fig. 2) is fastened with the collet bushing 2 in the center
hole. The blending tube 3 on the collet bushing prevents stray light.
The corrector (fig.3) consists of reflecting lens 2 and meniscus lens 3 spaced
by means of padding rings 4 in the mounting .
Eyepiece set (fig.2) consists of focussing mechanism 6, diagonal mirror 7, set
of symmetrical eyepieces f'=25mm and f'=0mm with barrel diameter 3.8mm
(.25”), Barlow lens mounted in the same one.
Finderscope 9 (fig.) is a telescope with 6x (8x) magnification and view field
8° (7°).
5. OPTICAL TRAIN
Telescope is developed on the basis of Klevzov’s original optical train, which
does not use any aspherical surfaces. Klevzov’s optical train (fig.4) consists of
primary concave mirror and correcting unit consisting of two single lenses 4,5.
The lens 5 is made in form of negative meniscus directed by concave side to the
observed object. The lens 4 is negative one having a reflecting surface.
Reflecting from the primary mirror a beam passes through correcting lenses
4,5, reflects from the reflecting surface of lens 4, passes through correcting lens
forming an image of observed object in the focal plane which is located behind
a primary mirror .
In the main the Klevzov’s optical train is an improved Kassegran optical train,
which has a spherical primary mirror and double lens corrector having a reflecting surface that to allow reducing an aberration. A meniscus 5 corrects a spherical
aberration and coma and fully compensates a little longitudional chromatic
aberration with the help of negative lens 4. Because two lenses of corrector are
made of the same mark of glass a secondary color of system is extremely little
one, and correction of the residual aberration is perfect that to allow obtaining
an image of observed object which can be compared with the image of object
obtained with the help of mirror telescope. Besides, Klevzov’s optical train is not
subject to unadjastment.
0
The lacks of aspherical surfaces, high quality of correction of the residual
aberration in the wide range of spectrum and small length are indisputable advantages of Klevzov’s optical system, that to allow satisfying all requirements of
amateur astronomer.
Telescope is completed with two symmetrical eyepieces f'=25mm and
f' = 0 mm and 2x Barlow lens. For easy observation of celestial objects near by
zenith an eyepiece set of telescope is turned to optical axis of tube by 90° with
the help of diagonal mirror 5. To locate an object in the center of view field the
telescope is completed with finderscope 6, which consists of objective lens,
reticle with the cross and eyepiece.
Fig. 4. Optical train of telescope:
- primary mirror; 2 - eyepiece; 3 - diagonal mirror;
4 - reflecting lens; 5 -meniscus lens; 6 - viewfinder
6
1
2
3
4 5
6. TELESCOPE ASSEMBLING
Prior to assembling the units and parts should be cleaned from the sluicing
compound of the plant.
The telescope is assembled in the following way.
The finderscope is mounted on the tube in two rings and fixed with six set
screws available on the rings.
In transportation and storage a hole in the eyepiece tube is plugged with a
stopper which should be removed and put in the case in preparation for operation.
For obtaining the required magnification of the telescope the respective eyepiece or the eyepiece with Barlow lens (fig. 4) is inserted in the eyepiece tube.
2
7. ORDER OF OPERATION
7.. Operation with telescope
The magnification of the telescope is large and consequently its field of view
is low. Therefore the telescope is provided with the viewfinder.
The optical axes of telescope and viewfinder must be aligned. Set the reticule
8 (fig.5) into the eyepiece 25 mm and then mount them into the focuser. Aim
the telescope at a remote object. Align the object’s image with the crosshair by
means of six setting screws.
After aiming of polar axes the setting circles can be used to find a celestial
object by its coordinates.
7.2. Photographic observations
Photographing star fields is carried out with the use of the telescope in the
main focus. To make it one should use a small size 35-mm camera or other
devices having fitting thread of 42x.0mm or 42x0.75mm. To mount a camera
it is necessary to remove eyepiece from tube and to mount a bushing with the
thread 0 (fig.5) of 42x.0mm. If it is necessary one should mount an adapter 9
on the bushing when using the telescope with camera provided with the thread
42x0.75.
Mounted a camera one should make a focus it and to balance the telescope.
The exposures, which are required for photographing the star fields, are tenths
of minutes without hindrance of the street lighting. Therefore, for this period of
time one should see to it that the camera follows the sky precisely in its diurnal
rotation. Near the center of the field of view of the camera one chooses the
bright star to which the telescope is pointed. To keep the star on the reticle cross
hairs of the finderscope is the problem for an observer for the whole period of
exposure. As the cross-hairs of the finderscope is not illuminated, the image of
the guide stair should be slightly defocused in order to cross a light circle of the
unsharp image of the star by the cross-hairs and to keep the star in this position
for the period of exposure.
One applies minor corrections for a clockwork drive keeping the star on the
cross hairs for the whole period of exposure. One corrects the position of the
guide star with the micrometer screw of the declination axis if necessary. To
obtain the minimum corrections in declination the polar axis should be set as
precisely as possible to the celestial pole. One should remember that if the polar
3
Fig. 5. Tools and accessories:
– cap; 2 – eyepieces; 3 – Barlow lens; 7 – blind; 8 – reticule; 9 – adapter; 0 – bushing
3
2
1
7
8
9
10
4
axis is set incorrectly, even in the case when the star image is kept on the crosshairs, the images of the stars at the edges of the field of view appear as dashes.
7.3. Telescope and atmospheric conditions
Telescope has a high magnification. In this case one should remember the
following feature. When increasing a magnification of telescope a distortion of
image to be made by aerial heterogeneity becomes more visible. It is a scintillation and distortion of image of remoted objects, scintillation and distortion of
image of stars, reduction of sharpness of small parts of Moon and stars. So, one
should make a testing of telescope resolution by double pares of equal brightness
and permeability by photometric standards, observation of little contrast parts of
planets in good atmospherical conditions such as calm, high transparence of
atmosphere and low turbulent air torrents.
Because a resolution of telescope is sufficiently high the testing should be made
in atmospherical conditions which are valued by Pikering’s scale. It is 6 scopes
that to allow obtaining the satisfactory and good images when diffractional disk
of star is visible constantly.
There are some meteorological factors, which can reduce a quality of image such
as mist, dust and so on. These factors reduce a transparence of atmosphere that to
reduce a permeability of telescope considerably. This factor is especially noticeable in observation of remoted objects, but sharpness of image is not changed.
It is not necessary to remind that observation through the window is possible
if the ambient temperature in the room and temperature out of door are not different. Otherwise the warm air coming out of the window deteriorates the images
so that observations are impossible whatsoever. Besides, inequality of surfaces
of window can distort an image.
If it is necessary to make an observation out of door, one should stay the
telescope in the street within 30 minutes so that all parts of telescope have the
same temperature.
In observation at cold damp nights a moisture can penetrate into the telescope
tube. If the telescope is covered, optical surfaces can get misted under direct
sunlight. So, one should protect the telescope from the direct sunlight. It is recommended to stay it in dark cold room for some time. But if the mirror got misted
it is not necessary to wipe it. One should open the telescope and stay it within
30 minutes in daylight. The moisture is evaporated in full.
After operation one should pack the telescope and store it according to the
rules of storage.
5
8. MAINTENANCE
For faultless operation the telescope should be kept in cleanness and protected
against mechanical damage. The metal surfaces are periodically cleaned by using
clean soft napkins, then wiped with a napkin impregnated with acidless vaseline,
after that with a dry napkin.
The aluminized mirrors require particular care. The accumulated dust is
removed only with the use of a soft brush or cotton wool tampon. If a visual
inspection reveals the need to clean the main mirror prepare it as follows: remove the eyepiece assembly with gearing, remove the screws (fig. 3), mark
the position of thread holes in mirror assembly for following reassembly, extract
the mirror assembly and place it with mirror surface upward. Clean the surface
with soft brush and then with cotton wool swab wetted with ether or alcohol.
Residual cotton fibers can be removed by air blasting.
The reassembly is done in reverse order. To avoid a readjustment of main mirror
the position of mirror assembly must correspond to the mark made previously.
The corrector should not be disassembed for cleaning. In the case of need the
meniscus surface is cleaned with removed main mirror assembly.
A cleaning of optical parts and adjusting of telescope is prohibited before
warranty expiration. It requires care and thoroughness and should be fulfilled in
the case of absolute necessity only.
After unintentional disalignment, cleaning or reassembling an adjustment of the
telescope can be need. In that case remove the cover 9 (fig.2), aim the telescope
at a star of 4-5m at maximal magnification and adjust the mirror on ball hinge
5 by means of adjusting screws 4 to get diffraction image of the star.
To adjust the primary mirror , loosen three of the screws 4 (next nearest order) by one or two turns and use the others three for adjusting. Loosen or tighten
according screws depending on deformation direction of focused star image.
Needed screw and action is found easy by trial method. Do not loosen or remove
all six screws since the mirror can fall out.
If weather does not allow viewing stars, the adjustment can be made with slight
defocused image. For such image proper adjustment is achieved when energy is
distributed uniform around center.
After adjustment, tighten all screws successively when viewing and in the case
of need correcting diffraction image of the star. Set the cover 9.
Remember that the adjustment procedure requires some experience and
skill.
6
9. RULES OF STORAGE
It is recommended practice to store the telescope in the heated room with the
relative humidity of maximum 80% at the temperature from 5° C to 40° C.
It is recommended to avoid any strokes and shakes.
It is forbidden to store any acid, alkali and materials educing moisture or
chemical active gas and streams.
0. ACCEPTANCE CERTIFICATE
Telescope serial № . . . . . . . . . . is found fit for service.
Date of manufacture and slushing _________________________________
Signatures __________________________________
7
SUPPLEMENT
Table of close stellar pairs for testing image quality of the telescope
αPsc h59.4m +02°3’ 4.3-5.3 .9’’ Pisces
γCet 2h40.7m +03°02’ 3.4-4.4 2.8’’ Cetus
ξOri 5h38.2m -0°58’ 2.0-4.2 2.5’’ Orion
αGem 7h3.4m +32°00’ 2.0-2.8 .8’’ Gemini
εHyd 8h44.m -06°36’ 3.5-6.9 2.9’’ Hydra
σ2Uma 9h06.0m +67°20’ 4.9-8.2 2.7’’ Ursa Major
38Lyn 9
h
5.8m +37°07’ 4.9-6.0 2.8’’ Lynx
ξUma h5.6m +3°49’ 4.4-4.8 2.9’’ Ursa Major
ξBoo 4h38.8m +3°56’ 4.6-4.6 .2’’ Bootes
εBoo 4h42.8m +27°7’ 2.7-5. 3.0’’ Bootes
µDra 7h04.3m +54°32’ 5.8-5.8 2.2’’ Draco
τOph 8h00.4m -08°’ 5.4-6.0 2.0’’ Ophiucus
70 Oph 8
h
02.9m +02°3’ 4.0-6.0 2.4’’ Ophiucus
ε1Lyr 8h42.7m +39°37’ 5.-6.2 2.7’’ Lyra
ε2Lyr 8h42.7m +39°37’ 5.-5.4 2.2’’ Lyra
δCyg 9h43.4m +45°00’ 3.0-6.5 2.2’’ Cygnus
µCyg 2h4.9m +28°30’ 4.7-6. .8’’ Cygnus
ξAqr 22h26.3m -00°7’ 4.4-4.6 .8’’ Aquarius
Name
of star
Coordinates
h, m
ang.
degrees,
ang. min.
Magnitude,
m
Visible
distance,
ang. s.
Constellations
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