In the age of CCD chips astrophotography is much easier than it was before. The main advantage of CCD chips compared with conventional emulsion based photography is the high sensitivity. The benefit is that deep-sky images can be obtained in a few minutes. Furthermore the images are processed on your own computer.
Alas: astronomy CCD cameras usually also have astronomical price tags.
However, if you are a planetary observer, you can use the less expensive web cameras [Webcam], which sensitivity is sufficient for the major planets, Sun and Moon. Until recently these webcams could not be used for deep sky imaging, as these faint objects require longer exposure times that the standard webcams offer.
But the newest developments have changed this dramatically, as you will see!
In September 2001 a revolutionary webcam modification was invented by QCUIAG member Steve Chambers: several standard webcams can be modified by electronic surgery enabling longer exposure times, so that deep-sky objects can be imaged now!
To honour the inventor all webcams modified this way now bear the suffix SC. Look here to obtain full details about the modification.
Steve Chambers: THANK YOU for this great invention!
Please NOTE that Steve Chambers has the sole copyright of the above mentioned modification and all other modifications shown on his website! Here is the Steve Chambers copyright statement
You want to know if a particular camera is suitable for astrophotography or can be modified for long exposure imaging? Dave Molyneaux has the answer for you!
Here is how Matthias Meijer does the long exposure modification on a Philips SPC900NC webcam.
Steve Chambers has supplied the following modification identification overview:
|SC1||A||basic long exposure modification|
|SC1.5||A||basic long exposure modification + amp switch|
|SC2||A|| basic long exposure modification + amp switch + separate interlaced
For some reason this version never got very popular; the supporting software DESIRE can be downloaded here
|SC3.1||A||Replacement of CCD with a ICX424|
|SC 3.2||A||Replacement of CCD with a ICX424 + basic long exposure modification|
|SC 3.3||A||Replacement of CCD with a ICX424 + basic long exposure modification + 2x1 on chip binning|
|SC 4.1||A||Replacement of CCD with a ICX414 (Greg Beeke)|
|SC 4.2||A||Replacement of CCD with a ICX414 (Greg Beeke) + basic long exposure modification|
|SC 4.3||A||Replacement of CCD with a ICX414 (Greg Beeke) + basic long exposure modification + 2x1 on chip binning|
The easiest way to verify that your SC3 camera is indeed working is to cap the camera so that no light falls on the CCD, then put it in long exposure mode and capture an image for say 90 seconds.
Note: make sure you have the camera running at 5 fps !
Then you should see hot pixels.
If you do not see hot pixels your camera is not working in long exposure mode, alas.
You can perform this test indoors, even during the day.
I am the happy owner of a Vesta SC3.2A B/W and a Colour camera.
Both are cooled; the colour camera is fitted with an ICX424AQ CCD sensor and the black/white camera has the far more sensitive ICX424AL CCD sensor inside.
Both cameras have been fitted with a threaded ring, which ingeniously accepts an 1,25" nose piece or an M42x1 threaded adapter with filter thread inside.
I checked the long exposure cable and all was perfect; also I was running the camera at 5 fps.
I ran Windows/ME and my laptop has 3 parallel ports, with as addresses 0278, 0378 and 03BC.
With "LPTRead" [freeware that alas has disappeared from the internet] I saw that some program/utility on my laptop was changing the contents of ports 0278 and 0378, and when that happened I also saw the K3CCDTools preview change.
In K3CCDTools I selected port 03BC because a previous experience taught me that whatever program was messing with the settings of the parallel ports, 03BC was not interfered with.
In spite of my K3CCDTools setting at port 03BC the problems persisted. Obviously my system was not 'listening' to my K3CCDTools setting, but used port 0278/0378 instead.
Then a thought entered my mind: my laptop had been to a shop for repairs and maybe those guys had done something to my BIOS settings?
I fired up the CMOS/BIOS settings and noticed that the parallel ports were in AUTO select mode. I quickly modified the setting from AUTO to 03BC and my problems are over!!!
On February 18, 2004 Matthias Meijer came over and applied the RAW mode on my SC3a black and white camera via the WcRmac software made by the TWIRG Group; THANK YOU TWIRGERS !!!
The results were stunning, as you can see yourself in the following image:
Note: I understand that the market for CCD's is highly volatile and that the stock/price situation changes rapidly.
So: when someone needs a certain CCD I would recommend to contact several suppliers to get the best value for money.
Dark frame test result:
60 seconds exposure, RAW mode, ampoff, Brightness 50, Gamma 100, Gain 100, ambient temperature 27C, Uncooled.
This standard unmodified camera saw first light on August 16, 2003 and I intend to use this camera to image the main planets and the moon.
Philips ToUcam Pro PCVC740K
I thank Matthias Meijer who gave this ToUcam a flattened front which enables me to use my Vesta Mogg adapter.
Matthias also supplied the following pictures:
I bought this webcam on March 10, 2005 via a Dutch e-bay for Euro 40,00
Technically the 840K is identical to the 740K, as Matthias Meijer has explained on his website.
Currently this 840 ToUcam is just spare webcam for my ToUcam 740.
Philips ToUcam Pro PCVC840K