Introduction

Conclusion

T he advent of CCD cameras was more arevolution than an simple evolution in the small world of amateurastronomy. CCD sensors  (Charge Coupled Device, the sameones which are used in video recorders) are very sensitive, andthey reduce the time exposition in a dramatic way (compared totraditionnal argentic sensors). By the way, they allow to freezethe atmosphere turbulence by using very short exposition inplanetary photos. Only few minutes are needed to see very fewluminous objects in deep sky observation.There are othersadvantages with this recent technics : one can see immediatly theimage on the computer screen, numerical image processing is veryeasy and powerful (processing which are often impossible torealize in laboratory for argentic photo). But unfortunately,this techics costs a lot (price of basics commercial camera isapproximately $1000) and not very easy to perform for neophyts.I's also possible to use a conventional video recorder or smallvideo camera, which we can now find some performing models. Onecan plug this cameras to a computer through a video conversionboard, but they are generaly expensive.

To begin with CCD, it ispossible to use another solution, which is nice and cheap. It'svery easy to perform, even for a neophyt. One can find some smallcommercial video cameras which are directly on a computer (orthrough a conversio board). They are commonly called ''Web Cam'',as they are generaly used for ''visioconference'' throughInternet. Through some small and easy modifications (described in Modification and Adaptation pages) , it is possible to usethem for astronomical applications. Different models can be used:

Cliquez ici CONNECTIX QUICKCAM B&W
(320x240, parallel port), unfortunately no more sold ;-(

Cliquez ici CONNECTIX QUICKCAM COLOR 2
(640x480, parallel port), no more sold too arghhh !

Cliquez ici CONNECTIX QUICKCAM COLOR VC
(640x480, USB or parallel port), 490FF.

Cliquez ici CONNECTIX QUICKCAM PRO
(640x480, USB or parallel port), 1000FF.

Cliquez ici CREATIVE LABS WEBCAM 2
(704x576, parallel port), 500FF.

Cliquez ici OLITEC VISIOLITEC MMP-2/VCB2
(640x480, parallel port) 2000FF with modem included.

Cliquez ici AB SOFT VCAM CP-58
(640x480, parallel port) 1550FF

Cliquez ici KODAK DVC 323
(640x480, USB port), 1500FF.

Cliquez ici INTEL CREATE & SHARE YC76
(320x240, USB port), 1500FF.

There is a point importantton note, B&W sensors are generaly more sensitive than colorsensors, so they are better to detect dim objects. Moreover, thecolor sensor needs 3 pixels (with red, green and blue filters) tomake a color pixel. By the way, the resolution is lower.

These differences havebeen noticed with the Creative Labs  Webcam II testing. Although this camera hasa good quality/price balance, testing revealed that it is lessefficient for astronomical uses. But an article written by A.LOPEZ shows that it's possible to obtainsome results with the Webcam II.

Some recent testings madeby J.F.MOURRON show that the QuickCam Color VC isvery efficient for planetary applications. It's currently thecamera that we recommend to start with CCD astronomy, and it'squality/price balance is very nice. The modifications for thiscamera are the sme than the ones for the Qcam B&W. Thiscamera costs approximately 500 FF in France.

H.ZAOUALI uses another camera : theConnectix QuickCam color.

Conclusion

Beginning with a QuickCamis very beneficial, as it's possible to deal with problems whichare frequently met in CCD astronomy (focusing's difficulties,difficulties to point an object due to the small size of CCDsensors, etc...) which the real time visualisation gets easy.Comparing the CCD photography to the traditionnal argenticphotography shows a much easier performing for the first one, andthe faculty to see the image just after taking it gets anincredible feeling. The main interest of the quickcam is to makethe first steps in CCD  astronomy for a very cheap cost (forsmall astronomy clubs or single people). The possiblities arereally huge : lunar, planetary or double stars'images,occultation animations, jovian satellites' movings, planets rotation, and many others... And now, one can findportable PC foe less than $1000 in computer big stores.

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