"QuickCam" Adaptation for use in Astronomy

The necessary modifications are:

1. To remove the objective and the infrared filter (small bluish plastic)
2. To assemble the electronic components (a small printed circuit, circular in shape and with a diameter of approximately 5 cm, containing the CCD and the circuits), to render the camera more suited to its new use.

Not all electronic components are within the camera "head" (the analog to digital converter and the interface with the computer are on the 25 pins connection at the cable end) and may not be replaced. We may increase the cable length by adding other cables in series, but the original connection to the computer must be maintained..

The assembly must allow the CCD to be in the center, and perpendicular to the optical axis of the telescope, so that the CCD area remains in focus and the images suffer no distortion.
 

In "QuickCam's" the CCD is surrounded by a plastic piece which fixes the I.V. filter and to which the objective is bolted. If we wish to use the camera for instruments presenting low focal relation (f/D), that is, bright, this piece may induce vignette and should be removed. On the other hand, the non removal of the I.V. filter may be the ideal option for those who wish to use the camera basically to obtain sun images. However, do not forget that the removal of this filter will increase the camera sensitivity considerably. I chose to maintain said plastic piece (I may reinstall the objective if I so wish) but I removed the I.V. filter. I place the prepared camera in a plastic box of the type found in shops selling electronic material.
 

The camera is tiny and may be easily adapted to any telescope or objective. The camera may be used in primary focus (with or without Barlows ) , ocular projection

(preferable in the case of small instruments) and adapted to teleobjectives. It is worth insisting on the following: try to avoid, as much as possible, to touch the CCD surface. Clean the CCD surface with a soft brush to remove the small dust grains which are bound to collect on it . You may also employ flat-field techniques used on CCDs for digital removal of stains caused by undesirable dust.
 

Connecting the "QuickCam" to computer

The "QuickCam" (Windows version) communicates with the computer through a parallel door, being fed (5V CC) by a connector inserted in the keyboard cable (there are 2 types of connectors available). Many (though not all) portable computers are provided with a socket which allows the connection to an external keyboard. In case there is such a socket, it may be used to feed the camera; however, there is always na alternate solution for the remaining computers.

Regarding camera feeding, there are two options: :

1. To use an additional feeding cable, the length of which should be equivalent to the extra "parallel" cable.
2. Or choose a new feeding source to be installed next to the camera. I personally followed the advice of Antonio Cidadão and chose the 2nd alternative.
3. I therefore bought a battery rack which enables me to place a set of 4 AA batteries in series. Our output will be 6V, which is perfectly acceptable for the camera (even though we have to reset the White-balance); if we use rechargeable nickel-cadmium batteries, we will reach 4.8V, which is nearer . As a result of the small consumption of the camera, each charge is sufficient for several sessions (of many hours). You should always have another set of batteries ready for use.

Transformers should not be used because they produce such noise and interference that it is impossible to obtain images. A DIN nut was adapted to the plastic battery rack presenting 5 holes in a semicircle (shown here with the convex portion upwards and numbered 1 to 5 from left to right), numbers 2 and 4 being respectively connected to the negative (-) and positive (+) poles on the rack. The remaining 3 stay off. This "nut" end is connected to the "screw" end provided with the "QuickCam" cable.

Software

The number and interval between images to be automatically obtained in a series, as well as the choice between "real time" and variable "time-lapse" animations. The sequence of phtographic pictures obtained are temporarily kept in a "ciber"- ("Film Roll") with a capacity of up to 36 exposures.

Antonio Cidadão recommends the use of sequences of 8 exposures, obtained in periods of minimum turbulence. We may view the Film Roll immediately through the QuickPICT, choosing and keeping only the best on the disk, and then emptying the ciber-film to start a new cycle of pictures. This procedure bears the advantage of a much greater probability of obtaining "decent" images, even in nights without ideal stability conditions. It is also quite easy to obtain AVI animations:

1-To demonstrate the influence of atmospheric turbulence ( seeing) on star images.

2- To check the telescope collimation using unfocused images.

3- Telescopic observations of Planets using real time animations.

4-To demonstrate the periodic error of assembly .

5-To record the movement of Jupiter satellites , stars and Planets being hidden by the Moon using accelerated animations( time - lapse). The images are kept unzipped (BMP, TIFF, AVI unzipped). JPEG zip results in loss of information on images, which becomes rather evident when it is necessary to "process" them, and the quality degradation in zipped AVI sequences is also irreversible.

Obtaining images with "QuickCam"

"QuickCam" allows you to obtain good quality astronomic images, provided that the object to be photographed/filmed is bright enough. Such objects include the Sun (CAUTION!! Always use sun filters of adequate resistance and quality (I use a "type 2 plus" "Thousand Oaks Optical" filter, duly set before the correcting plate of my 8"opening Schmidt-Cassegrain), the Moon, the brightest planets (Mercury, Venus, Mars, Jupiter and Saturn), and bright stars.

The image size and zoom, time of exposure (brightness).

Contrast and white balance.

1- Let us disable the automatic mode (which allows the camera itself to choose the time of exposure). For the Moon and planets, the best results are obtained when contrast is set to zero (0), and the choice of the adequate offset (white balance) is left to the camera, and only then choosing the most suitable time of exposure manually (brightness). For the Sun, or in case we wish to stress planetary details which are not very evident, we should increase contrast appropriately. "QuickCam" in B/W produces 6 bit digital images, that is, with 64 levels of gray, much less than the 256 ( 8 bits) detected by the human eye.

To obtain images with the best possible quality (chromatic dynamics), it is necessary to proceed to the adequate adjustments (contrast, brightness and time of exposure) before we take the picture, as we do when we take conventional pictures.

Image processing

We use the excellent image processing AdobePhotoShop software (I use version 5), and assuming there are 8 original images, the average is determined as follows (always combining images two by two):

1 - Transform the images kept on the disk in BMP format from indexed color to grayscale, going to Image menu and then to Image Mode, activating the grayscale.
2 - Open two of the original images, one to remain as the active one
3 - Go to "Image" menu
4 - Select the "Apply Image" option
5 - Select "Source:" the name of the second image of the two
6 - Select "Blending: normal"
7 - Select "Opacity: 50%"
8 - Enter "O.K."
9 - In this way, an intermediary image is created, and should be filed
10 - Repeat procedures 1 to 8 for the remaining three pairs of images
11 - Now, each of the four intermediary images behaves as an original one, and procedures 1 to 9 must be repeated
12- Finally, we take the average of the two images which originated with step 10. It sounds complicated, but it is not, and allows us to see how the characteristics of the images improve little by little.

Some images

Thanks

The assembly and adaptation of the camera, its use and software handling were based in the works by António José Cidadão , a Portuguese amateur astronomer, a pioneer in the use of QuickCam, whom I thank very much for the encouragement and to whom I send my congratulations for the magnificent work with CCD.

A visit to his homepages is essential :António José Cidadão ,Member of A.P.A.A. (Associação Portuguesa de Astrônomos Amadores)

http://www.skypub.com/whatsup/acmovies.html

http://www.geocities.com/CapeCanaveral/5409/

http://www.terravista.pt/Guincho/1177/

I thank my friend Pedro Ré for what he taught me and for the encouragement he gave to create this homepage. As happens with António Cidadão, his works with QuickCam and CCD crossed frontiers and made the name of Portugal duly acknowledged by the world's astronomic community.

A visit to this homepage is a must:

http://www.geocities.com/CapeCanaveral/Lab/4171/qc.html

Other interesting links

http://ourworld.compuserve.com/homepages/chas_wray/

http://perso.wanadoo.fr/jf.mourron/astronom.htm

http://www.geocities.com/CapeCanaveral/5409/3d.html

http://www.geocities.com/CapeCanaveral/Hall/1439/qc.htm

http://www.geology.ewu.edu/jpb/lho/lho.htm

http://www3.gamewood.net/astronomy/ccdinfo/qc/

http://www.vub.ac.be/STER/www.astro/AstroCCD/AstroQC.htm

http://perso.club-internet.fr/uranos/disassemble_quickcam.htm

http://www.public.iastate.edu/~sdk/questarpix.html

http://www.mnsinc.com/daolath/astro/astro.html

http://idt.net/~metro6/

http://www.atm.dal.ca/~andromed/sun.html

http://www.egroups.com/list/astrocam

http://www.gfi.net./pryczek/

http://www.astrodurf.com/astrocam

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