Watec WAT-120N CCD Video Camera

The Watec WAT-120N is an excellent introduction to Deep Sky imaging for those who appreciate the versatility of a "True" video camera. The output of the camera can be displayed on a TV, VCR, Monitor, Laptop or desktop computer.

The On-Screen (Monitor) image of brighter objects Messier objects such as the Dumbell Nebula rivals processed CCD images. The views on the monitor are spectacular. This makes the Watec WAT-120N especially well suited for school, planetariums, college, universities and industry and both the beginning imager and advanced imager.

There is a separate remote control box for slow shutter speed (frame accumulation), gain, gamma (contrast) control and freeze frame.

The freeze frame button will freeze the on screen image on the monitor. This is useful when we have an image we want to describe or display for a large group. Once the screen image is frozen, the telescope can be slewed to the next object while a discussion is being given for the current on-screen image.

Specification:

• Auto Iris - A.E.S. / VIDEO Type Lens
• CCD Sensor (Model) - ICX418ALL EIA Sony
• Pixel Array - (640X480) 811 X 508
• Pixel Dimensions - 7.40mm X 5.95mm
• Total Pixels - 410K
• Pixel Size - 8.4 X 9.8 microns
• Frame Accumulation - MANUAL CONTROL BOX - 1, 2 TO 256 FRAMES
• Gain Control - AUTOMATIC / MANUAL GAIN 8-38dB
• Gamma Correction - 0.35, 0.45, 1.0
• Image Sensor - EIA SONY ICX418ALL.
• Manual Frame Accumulation Shutter - The OFF setting on the control box is the standard video shutter speed of 1/60 second (.017 second) for NTSC (EIA) frame and 1/50 second (.02 second) for CCIR (PAL) frame. Setting 1 is for one added frame etc.
• Minimum Illumination - Watec WAT-120N18TH MAGNITUDE DEEP SKY IMAGING WITH 8 INCH TELESCOPE 0.00002 lux at F/1.4 Planetary- 1/60 sec ONLY (see limitations section below) Integration (Deep Sky) mode - UP to 256 Frame accumulation for a 8.5 second NTSC 10.8 second PAL exposure.
• Operation Temperature - -20C TO +50C
• Operational Humidity - WITHIN 85%
• Power Supply - AC100V, 220V CAMERA POWER REQUIREMENTS DC10.2-13.8V 50/60Hz DC+12V Power supply weight Approx. 236g
• Resolution - 600 TELEVISION LINES
• Scanning System - 525 LINES 60 FIELDS/SECOND NTSC 625 LINES 50 FIELDS/SECOND EIA
• Signal to Noise Ratio (S/N Ratio) - 52 dB
• Sync System - INTERNAL / VD - LOCK (OPTION)
• Video Output - COMPOSITE BNC
• Weight - Camera weight 150 grams

MOUNT

You could have the best telescope and the best camera but they would be of no real use without a mount to track the star movements across the night sky. If the only purpose of your telescope was for visual use then the quality of the mount would be of less importance as long as the image stayed in the eyepiece for 10 to 20 minutes. Photograph on the other hand requires a mount to track at exacting standards. So not to show any star drifts in the image the mount must keep the stars within 1 pixel on the imaging CCD at all times when exposing.

 The mount Igomoo Observatory uses is a fork mount as shown below:

The mount sits on a wedge and is polar aligned so only one motor ( R.A. Drive) tracks the stars. The drive is a worm dive configuration. To help with tracking errors the computer onboard the telescope can eliminate the small errors associated with the worm gear. Known as PERIODIC ERROR CORECTION or PEC the computer slows down or speeds up the R.A. drive motor to compensate for any errors. It achieves this by first viewing a star at high magnification then using a cross hair eyepiece you must keep the star dead centre for the entire length of the worm gear, about 8 minutes. The small corrections you make to keep the star centered are recorded by the telescopes onboard computer and will later be played back to eliminate the errors.