Celestron CGEM 800 Telescope User Manual


 
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Home Position..................................................................................................................................................................................... 29
Light Control....................................................................................................................................................................................... 29
Factory Settings................................................................................................................................................................................... 29
Version................................................................................................................................................................................................29
Get Axis Position................................................................................................................................................................................. 29
Goto Axis Position .............................................................................................................................................................................. 29
Hibernate............................................................................................................................................................................................. 29
Sun Menu ............................................................................................................................................................................................ 29
Scrolling Menu.................................................................................................................................................................................... 30
Set Mount Position.............................................................................................................................................................................. 30
Set Mount Position....................................................................................................................................................................................... 30
Turn On/Off GPS ................................................................................................................................................................................30
Turn On/Off RTC................................................................................................................................................................................ 30
Periodic Error Correction .................................................................................................................................................................... 30
TELESCOPE BASICS..............................................................................................................................................................................................................32
Image Orientation......................................................................................................................................................................................... 32
Focusing ....................................................................................................................................................................................................... 33
Calculating Magnification............................................................................................................................................................................ 33
Determining Field of View........................................................................................................................................................................... 33
General Observing Hints .............................................................................................................................................................................. 34
ASTRONOMY BASICS...........................................................................................................................................................................................................35
The Celestial Coordinate System.................................................................................................................................................................. 35
Motion of the Stars....................................................................................................................................................................................... 36
Polar Aligning the Mount............................................................................................................................................................................. 37
Polar Align .......................................................................................................................................................................................... 37
Finding the North Celestial Pole................................................................................................................................................................... 39
CELESTIAL OBSERVING.....................................................................................................................................................................................................40
Observing the Moon..................................................................................................................................................................................... 40
Lunar Observing Hints ................................................................................................................................................................................. 40
Observing the Planets................................................................................................................................................................................... 40
Observing the Sun ........................................................................................................................................................................................ 40
Solar Observing Hints .................................................................................................................................................................................. 41
Observing Deep Sky Objects........................................................................................................................................................................ 41
Seeing Conditions......................................................................................................................................................................................... 41
Transparency ................................................................................................................................................................................................ 41
Sky Illumination........................................................................................................................................................................................... 41
Seeing........................................................................................................................................................................................................... 41
ASTROPHOTOGRAPHY........................................................................................................................................................................................................43
Short Exposure Prime Focus Photography ................................................................................................................................................... 43
Eyepiece Projection...................................................................................................................................................................................... 44
Long Exposure Prime Focus Photography ................................................................................................................................................... 46
Periodic Error Correction (PEC) .................................................................................................................................................................. 47
Using Periodic Error Correction................................................................................................................................................................... 47
Terrestrial Photography................................................................................................................................................................................ 48
Metering ....................................................................................................................................................................................................... 48
Reducing Vibration ...................................................................................................................................................................................... 48
CCD Imaging ............................................................................................................................................................................................... 49
Auto Guiding................................................................................................................................................................................................ 49
TELESCOPE MAINTENANCE..............................................................................................................................................................................................50
Care and Cleaning of the Optics................................................................................................................................................................... 50
Collimation................................................................................................................................................................................................... 50
OPTIONAL ACCESSORIES.................................................................................................................................................................................................53
APPENDIX A – TECHNICAL SPECIFICATIONS............................................................................................................................................................56
APPENDIX B – GLOSSARY OF TERMS............................................................................................................................................................................57
APPENDIX C – RS-232 CONNECTION................................................................................................................................................................................60
APPENDIX D – TIME ZONE MAP........................................................................................................................................................................................62
SKY MAPS................................................................................................................................................................................................................................64