How To ~

PC23C VIDEO CAMERA

By Bill Castro
July 2001


The discussion here is not too technical in nature. It is more along the lines of what is it  and how to use it. Comparisons are made between the PC23C, the Astrovid camera and holding a camcorder to the eyepiece. This is a copy of a program that was presented to the Wilderness Center Astronomy Club at their meeting on November, 2000. Allthough all material presented was current at that date, it may be outdated now.  Images taken with this camera are linked at the bottom. More are  available in the Photo Gallery pages under Video Archive.

Glossary of Terms

  • Gain- Sensitivity of the camera. Electronic gain typically boosts signal level and noise.
  • Electronic Shutter- Integration time for the CCD or actual time to take picture.
  • Gamma- Typically referred to as contrast.
  • Minimum Scene Illumination- (in lux) the lower the better. Older camcorders ~2.0 lux, PC23C 0,04 lux and Astrovid 0.02 lux.
PC23C Specs
  • Image Sensor 1/3 inch monochrome CCD
  • Pixels 510(H) x 492(V) 250,920
  • Horizontal resolution 460 lines
  • Minimum illumination 0.04 lux, f1.8
  • Auto shutter 1/30 1/100,000 sec
  • Lens C mount
  • Power Consumption 10 14 VDC, 200 mA
  • Dimensions 2.3 x 2 x 3.77 inches
  • Weight 192 g
  • CCD 4.9 x 3.7mm area (7x9 micron pixels)
  • Electronic shutter can be turned on/off
  • BNC video output connection
  • RS170 B&W video output - connects to a Video In of a TV, VCR or monitor
  • Microphone built in.

  • RCA audio output connection
PC23C Modifications (Circuit modifications can be made to do the following. Modifications are only a marginal help. See references for links.)
  • Manual gain adjustment
  • Manual shutter control
  • External power supply - Moving the regulator chip outside the camera box lowers chip temperature and reduces noise. 
PC23C Cost and Add-ons (For use with a SCT. Prices are as of November, 2000)
  • PC23C Camera                               $79.95
  • BNC to RCA adapter                         $2.95
  • AC (or DC) power adapter             $14.00
  • Celestron T to C adapter                 $27.00
  • Meade Variable Tele-extender       $39.95
  • Meade T adapter                              $26.95
  • Clear lens                                          $43.30

  • Total                                                 $234.10

    Note that a C to 1.25 inch adapter from ADIRONDACK  for $35.00 can replace the T to C adapter, tele-extender and T adapter. 

Comparison of PC23C vs Astrovid 2000
  • Price                            $80 to $250       $595
  • CCD area                 4.9 x 3.7 mm     6.4 x 4.8 mm
  • Min illum.                      0.04 lux          0.02 lux
  • Resolution                     460 lines         600 lines
  • Shutter         1/30 to 1/100,000 sec  1/60 to 1/10,000 sec
  • Shutter adj.             On/off or Mod      Manual
  • Gain adj.                            Mod           Manual
  • Contrast adj.                       NO            Manual
  • Microphone                        Yes              No


PC23C Applications (Best with bright objects. Not good for deep sky or faint objects.)

  • Occultation timing (excellent-highly recommended by IOTA)
  • Meteor strikes on the Moon (excellent)
  • Moon (excellent)
  • Sun (with solar filter) (excellent)
  • Jupiter (tricky)
  • Saturn (tricky)
  • Mars (tricky)

  • Venus (tricky)
PC23C How to use it
  • Prime focus, barlow or variable projection.
    • Prime focus can work with most scopes
    • A barlow or Variable projection may NOT work depending on the scope's focuser travel.
  • Control image brightness and contrast by:
    • Image size - Try to get the object to fill up as much of the screen as possible to let the cameras automatic controls make the appropriate adjustments.
    • Filters - These help reduce the brightness. Color filters, nebula filters and lunar filters may be used. Solar filter is a must with the sun.
    • Composition - In addition to image size, move the scope (especially the moon) to an area where there is more contrast, such as the terminator. Some of the brighter areas of the moon may bloom. The scope should be moved to show less of the moon to get better detail on the terminator.
    • The required combinations of the above will depend on the scope used.
  • Record to tape or display on monitor
    • S-VHS, Hi-8, VHS then 8mm in order from best to lowest resolution.)
  • Digitize on PC with frame grabber
    • Snappy or Dazzle ($80.00)
PC23C Pros and Cons
  • Pros
  • Cost
  • Occultation timing (It has a microphone)
  • Excellent for eclipse, solar or lunar imaging.
  • Fixed to scope compared to hand held camcorder-to-eyepiece.
  • Cons
  • Hard to adjust picture (Astrovid or camcorder works better on planets. Modifications are only marginal.)
  • Mechanical connections
Summary

Depends on what you are going to image and how often you will be using it. Works great to image moon and sun on tape or on a monitor. (Displaying it on a monitor is great for groups.) No adjustments are required. Planets are tricky. Filters and image size have to be adjusted to get the exposure and details right. This takes time in the field. The Astrovid has the neccissary manual controls to do this for you with minimal frustration. 

Images (More images are available at the Photo Gallery pages under Video Archive.)
Images with 80mm refractor

Images with 8 inch f/10 LX200 Images with 10 inch f/10 LX200 Images wth 12 inch f/10 LX200 Links and References

Modifications to Supercircuits PC23C  By Paul Goelz. Modifications to the video AGC (for manual gain control) and manual shutter control.

Video Capture Astrophotography  By Jim Ferreira. Excellent links and references.

From supercircuits.com
BNC to RCA adapter
Power supply, 12 DC 300ma adapter

From Edmund Industrial Optics
A clear lens on the camera consisting of Borofloat Window stock number K45-461 and a C-mount 20mm lens holder stock number K54-626. The clear lens keeps the dust off the camera CCD chip. Without it the chip must be cleaned for each use.

From astronomics.com
Meade and Celestron threaded adapters.
 

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