APPENDIX A – TECHNICAL SPECIFICATIONS

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

Fine Annealed Pyrex

 

 

 

Coatings

Starbright XLT Coating

 

 

Secondary Mirror: Material

Hand Figured Fine Annealed Pyrex

 

 

 

Coatings

Starbright XLT Coating

 

 

Central Obstruction

 

2.5”

(10% by area)

 

 

Corrector Plate:

Material

Optical Quality Crown Glass

 

 

 

Coatings

MgF2 Coatings both sides

 

 

Highest Useful Magnification

480x

( ~ 4mm eyepiece)

 

 

Lowest Useful Magnification (7mm

29x

( ~ 70mm eyepiece)

 

 

exit pupil)

 

 

 

 

 

 

Resolution: Rayleigh Criterion

.68 arc seconds

 

 

Dawes Limit

.57arc seconds

 

 

Photographic Resolution

200 lines/mm

 

 

Light Gathering Power

843x unaided eye

 

 

Near Focus standard eyepiece or

~ 25 feet

 

 

camera

 

 

 

 

 

 

Field of View: Standard Eyepiece

.64º

 

 

 

 

: 35mm Camera

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

81x

 

 

 

 

: Camera

41x

 

 

 

 

Optical Tube Length

17 inches

 

 

Weight of Telescope

24 Lbs.

 

 

Electronic Specifications

 

 

 

 

 

Input Voltage

 

 

 

12 V DC Nominal

 

Maximum

 

 

 

18 V DC Max.

 

Minimum

 

 

 

8 V DC Min.

 

Batteries Required

 

 

 

8 AA Alkaline

 

Power Supply Requirements

 

 

12 VDC-750 mA (Tip positive)

 

Mechanical Specifications

 

 

 

 

 

Motor: Type

 

 

 

DC Servo motors with encoders, both axes

Resolution

 

 

 

.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

 

 

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Celestron NexStar 8i manual Appendix a Technical Specifications