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Ritchey-Chrétien Robotic
Telescope Systems . . .
20"
ObservatoryScope Folded Newtonian Shown |
- Aperture Range: 20", 24", 32", 36" and 40" on
equatorial fork mounts.
- Design Applications: CCD imaging, CCD photometry,
aperture photometry, spectroscopy, visual use.
- Optical System: Ritchey-Chrétien, fully
baffled, featuring easy collimation adjustments for the primary, secondary and
the image plane.
- F/ratio: F/8 is "standard"; F/6.3 to F/12
Ritchey-Chrétiens, F/15 Cassegrain or other custom F/ratios are also
available.
- Focus Mechanism: Stepper motor secondary mirror
focus mechanism controlled by custom Optec TCF-S electronics.
- Optical Tube Assembly: Three part construction
featuring a DEC axis center box, removable front truss/secondary mirror
assembly and removable rear cell/primary mirror assembly.
- Fork Mount: Welded steel construction, computer
designed for ultra-low flexure.
- R.A.-DEC Perpendicularity: ±2 arc-seconds,
adjustable.
- Telescope Pedestal: Welded steel construction,
±2.5º azimuth and altitude adjustments.
- R. A. Drive Shafts/Bearings:
| (20") |
3-1/2" diameter cold rolled steel shaft with 3-1/2"
tapered roller bearings |
| (24") |
3-1/2" diameter cold rolled steel shaft with 3-1/2"
tapered roller bearings |
| (32") |
4" diameter cole rolled steel shaft with 4" tapered
roller bearings |
| (36") |
4-1/2" diameter cold rolled steel shaft with 4-1/2"
tapered roller bearings |
| (40") |
6" diameter cold rolled steel shaft with 6" tapered
roller bearings |
- Dec. Drive Shafts/Bearings:
| (20") |
3" diameter cold rolled steel shaft with 3" tapered
roller bearings |
| (24") |
3" diameter cold rolled steel shaft with 3" tapered
roller bearings |
| (32") |
3-1/2" diameter cold rolled steel shaft with 3-1/2"
tapered roller bearings |
| (36") |
4" diameter cold rolled steel shaft with 4" tapered
roller bearings |
| (40") |
4" diameter cold rolled steel shaft with 4" tapered
roller bearings |
- Drive System: Hybrid Band-Worm Drive (Patents
Pending)
- Drive System Electronics: ComSoft PC-TCS stepper
motor control system. ComSoft PC-TCS servo system is also available for $10,000
more.
- Pricing, excluding applicable taxes, shipping and
installation costs; Manufacturing Time:
| (20" RC) |
$150,000.00 |
10 months |
| (24" RC) |
$200,000.00 |
10 to 12 months |
| (32" RC) |
$375,000.00 |
18 months |
| (36" RC) |
$590,000.00 |
21 to 24 months |
| (40" RC) |
$770,000.00 |
24 to 30 months |
Call for pricing on Classical Cassegrain
systems.
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Product Description
Our ObservatoryScope Ritchey-Chrétien
Data-Visual Systems are high performance telescopes for both visual imaging and
electronic imaging applications. These systems are available in F/ratios
ranging from F/6.3 for wide field applications to F/9 for narrower field work
with larger image scales. Optionally, a conventional F/15 Cassegrain optical
system may be specified for high power and spectroscopic applications.
These instruments offer the greatest flexibility
for a variety of applications including electronic data acquisition and visual
use. They are excellent systems for instructional and educational purposes, and
are designed to be operated remotely through local networks or via the
Internet.
Optical Performance
The Ritchey-Chrétien optical system is the
optical design of choice by professional astronomers and observatories since it
is coma-free and offers a wide and well corrected field of view. These optical
systems are expensive because the design is difficult to manufacture to the
required tolerances. The F/6 focal ratio provides a wider field of view and
faster imaging, the F/8 focal ratio covers a broad range of applications, while
the F/9 focal ratio features a smaller secondary for higher power
applications.
Ritchey-Chrétien optical systems are coma
free and only have slight amounts of off-axis astigmatism. Conventional
Cassegrains, however, have strong off-axis coma which definitely is not
desirable. The Ritchey-Chrétien's slight off-axis astigmatism allows for
accurate photometry since the off-axis stellar images are tiny ellipses rather
than the strong comatic flares found in Cassegrains. The optical performance of
a Ritchey-Chrétien optical system is the best that can be obtained using
just two mirrors and no other correcting lenses.
We also offer F/15 Cassegrains specifically for
applications where a long focal length is necessary. Our F/15 Cassegrains are
specifically suited for high power visual work, photometry or spectroscopy.
Short focal ratio Cassegrains normally exhibit off-axis coma and moderate
off-axis astigmatism. However at F/15 these aberrations are very slight and do
not warrant the additional expense of the Ritchey-Chrétien optical
design.
Pointing and Tracking
Performance
ObservatoryScope Ritchey-Chrétien
Data-Visual Systems provide exceptional, observatory class pointing and
tracking capabilities. Our guaranteed minimum performance specifications for
our Ritchey-Chrétien and Cassegrain telescopes are shown below.
| Tracking Precision: |
<1 arc-second MAX** over 300 seconds; <10 arc-seconds
MAX over 1 hour |
| Raw Pointing Precision: |
<30 arc-seconds MAX to 30° from zenith; <45
arc-seconds MAX to 60° from zenith |
| Calibrated Pointing Precision: |
<5 arc-seconds MAX to 15° from zenith; <15
arc-seconds MAX to 60° from zenith |
| Pointing Repeatability: |
<3 arc-seconds MAX for an offset move of 5 degrees; <9
arc-seconds MAX for an offset move of 30 degrees |
| DEC Backlash: |
<1.5 arc-seconds MAX, repeatable |
** ObservatoryScope uses MAX (maximum
error) instead of RMS for all performance specifications.
Drive System
Specifications
| Hybrid Band-Worm Drive System
for 20" to 24" Aperture Telescopes: |
| Equivalent Gear Diameter: |
Performance equivalent to a 40" diameter, 2520 tooth
worm gear. |
| Primary Drive Disk: |
28" diameter sand cast aluminum precision bored and
turned on an industrial lathe. |
| Secondary Drive Disk: |
4" diameter precision bored and turned from aluminum
bar round stock. |
| Primary-Secondary Disk Coupling: |
Belt Technologies 1-1/8" width, 0.015" thick, 301HY
high yield stainless steel precision fabricated band. |
| Worm Gear: |
5.625" diameter, 7075 aluminum worm gear, 360 tooth,
anodized aluminum worm. |
| Band Drive to Worm Drive Coupling: |
1" diameter stainless steel shaft supported by tapered
roller bearings. |
| Band Drive Ratio: |
7:1 |
| Worm Drive Ratio: |
360:1 |
| Worm-Motor Ratio: |
3:1 |
| Overall Reduction Ratio: |
7560:1 |
| Steps / Motor Revolution: |
1600:1 using x8 microstepping and 1.8 deg/step stepper
motors. |
| Steps / Telescope Revolution: |
12,096,000:1 yielding 9-1/3 steps per arc second or
0".107 arc second per step. |
| Required Motor Torque: |
<1 ounce-inches of torque with the telescope in
balance; <4 ounce-inches of torque with the telescope 20 foot-pounds out of
balance. |
| Periodic Error: |
less than 1.0 arcsecond MAX without PEC
correction. |
| Tooth to Tooth Error: |
less than 1.0 arcsecond MAX. |
| Drive System Backlash: |
less than 1.5 arcsecond MAX. |
| Full Worm Cycle: |
Approximately 34.192 seconds. |
| Hybrid Band-Worm Drive System
for 32" to 40" Aperture Telescopes: |
| Equivalent Gear Diameter: |
Performance equivalent to a 54.5" diameter, 2160 tooth
worm gear. |
| Primary Drive Disk: |
36" diameter sand cast aluminum precision bored and
turned on an industrial lathe. |
| Secondary Drive Disk: |
6" diameter precision bored and turned from aluminum
bar round stock. |
| Primary-Secondary Disk Coupling: |
Belt Technologies 1-1/2" width, 0.025" thick, 301HY
high yield stainless steel precision fabricated band. |
| Worm Gear: |
9.09" diameter, 660 bronze worm gear, 360 tooth, 304
stainless steel worm. |
| Band Drive to Worm Drive Coupling: |
1-1/2" diameter stainless steel shaft supported by
tapered roller bearings. |
| Band Drive Ratio: |
6:1 |
| Worm Drive Ratio: |
360:1 |
| Worm-Motor Ratio: |
3:1 |
| Overall Reduction Ratio: |
6480:1 |
| Steps / Motor Revolution: |
1600:1 using x8 microstepping and conventional 1.8
deg/step stepper motors. |
| Steps / Telescope Revolution: |
10,368,000:1 yielding 8 steps per arc second or 0".125
arc second per step. |
| Required Motor Torque: |
<1 ounce-inches of torque with the telescope in
balance; <4 ounce-inches of torque with the telescope 20 foot-pounds out of
balance. |
| Periodic Error: |
less than 1.0 arcsecond MAX without PEC
correction. |
| Tooth to Tooth Error: |
less than 1.0 arcsecond MAX. |
| Drive System Backlash: |
less than 1.0 arcsecond MAX. |
| Full Worm Cycle: |
Approximately 39.189 seconds. |
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Product Summary
In summary, ObservatoryScope
Ritchey-Chrétien Data-Visual Systems offer exceptional optical
performance combined with superb pointing and tracking performance. These
systems are available in several F/ratios to suit the user's specific
applications and needs. F/8 is the most popular focal ratio since it is
suitable for the broadest range of applications. The F/8 system may be
moderately tele-compressed to F/6 for wider imaging fields, or a Barlow may be
used to convert the telescope to F/16 for extremely high power work. |
