Celestron NexStar 8i User Manual
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A
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P
P
P
P
E
E
N
N
D
D
I
I
X
X
A
A
–
–
T
T
E
E
C
C
H
H
N
N
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A
A
L
L
S
S
P
P
E
E
C
C
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I
F
F
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I
C
C
A
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T
T
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O
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S
S
Optical Specification
11022-XLT-SE
NexStar 8i
Design Schmidt-Cassegrain
Catadioptric
Aperture
8 inches (203.2mm)
Focal Length
80 inches (2032mm)
F/ratio of the Optical System
10
Primary Mirror: Material
Coatings
Fine Annealed Pyrex
Starbright XLT Coating
Secondary Mirror: Material
Coatings
Hand Figured Fine Annealed Pyrex
Starbright XLT Coating
Central Obstruction
2.5” (10% by area)
Corrector Plate: Material
Coatings
Optical Quality Crown Glass
MgF2 Coatings both sides
Highest Useful Magnification
480x ( ~ 4mm eyepiece)
Lowest Useful Magnification (7mm
exit pupil)
29x ( ~ 70mm eyepiece)
Resolution: Rayleigh Criterion
Dawes Limit
.68 arc seconds
.57arc seconds
Photographic Resolution
200 lines/mm
Light Gathering Power
843x unaided eye
Near Focus standard eyepiece or
camera
~ 25 feet
Field of View: Standard Eyepiece
: 35mm Camera
.64º
1.0º x .68º (1.6º x 1.07º - with optional
Reducer Corrector)
Linear Field of View (at 1000 yds)
34 feet
Magnification: Standard Eyepiece
: Camera
81x
41x
Optical Tube Length
17 inches
Weight of Telescope
24 Lbs.
Electronic Specifications
Input Voltage
Maximum
Minimum
12 V DC Nominal
18 V DC Max.
8 V DC Min.
Batteries Required
8 AA Alkaline
Power Supply Requirements
12 VDC-750 mA (Tip positive)
Mechanical Specifications
Motor: Type
Resolution
DC Servo motors with encoders, both axes
.26 arc sec in Azimuth, .32 arc sec in altitude
Fork Arm
Cast aluminum, with integrated hand control receptacle
Electronic Hand Control Specifications
Slew speeds
Six slew speeds: 6º /sec, 2º /sec, 128x, 64x, 16x, 8x
Tracking Modes
Alt-Az, EQ North, EQ South , Off
Optional Computerized Hand Control Specifications
Hand Control
Double line, 16 character Liquid Crystal Display
19 fiber optic backlit LED buttons
Slew speeds
Nine slew speeds: 6º /sec, 3º /sec, 1.5º/sec, 128x, 64x, 16x, 8x, 2x, 1x
Software Precision
24bit, 0.08 arcsec calculations
Ports
RS-232 communication port on hand control
Tracking Rates
Sidereal, Solar and Lunar
Tracking Modes
Alt-Az, EQ North & EQ South
Alignment Procedures
2-Star Alignment, Auto Two-Star Align, EQ North/South
Database 40,000+
objects
400 user defined programmable objects.
Enhanced information on over 200 objects
Complete Revised NGC Catalog
7,840