As CCD cameras are now available as commercial products for amateur astronomers, it is necessary to analyze the reasons to build such a camera. For a better understanding, we will examine the commercial offer.
In top-of-the-line cameras we find them capable of very fast readings of the image thanks to the use of powerful computer interfaces. These cameras have electronic components of very low noise and CCD sensors with more than 4 million pixels. Moreover, there are detectors with a spectral response extended in the blue range. That kind of performance requirement can be satisfied if the demanding amateur or professional is willing to pay $8,000 or more. The intermediate range of equipment is very popular with prices from $1,500 to $4,500, and utilize the KODAK KAF-0400 CCD sensor. In general, this equipment is very effective and has almost infinite possibilities if you can use them well.
At the low end, we find products that cost between $1,000 and $1,500 . These products are either cameras which specialize in autoguiding, or more universal cameras capable of the simultaneous functioning of autoguiding and traditional imagery systems only. However, in order to lower the prices, the detector is often of very small physical dimensions. If a surface area of 10 mm2 makes it difficult to learn this technique, the intensive use of this type of product can become rather painful and discouraging. Indeed, it is not easy to point and guide a telescope if the detector has a field of view of only a few arc minutes. Moreover, the observer may not be equipped with a telescope that has optical coders or other equipment to help in the guiding.
In spite of a simple design, the Audine camera has the performance of a product in the medium of range but a price that is in the low end range of prices. To achieve this goal, we removed the expenses related to assembly since that is your task. We also preferred not to use the superfluous elements, and we selected well known solutions. Thus, with this information to guide you, it will be easy to find components that are not very expensive. As a result of such complete documentation, you are almost sure to have an operational camera. We also think that your principal motivation is not the construction of a camera, but to make good images as quickly as possible with your camera. It is also our objective with this project.
The advantage of building a camera it is that you will have the knowledge and skill to repair it if it breaks down. You will never hesitate to open the Audine in the event of problem. This is not true with a costly commercial camera. These should be returned to the manufacturer for repair, and you might wait several months before being able to continue the observations.
The Audine system is open and dynamic. You can adapt the camera according to your own needs.
Of course, you must make this camera yourself (we will speak about that in other chapters). We cannot guarantee 100% success to you even if Audine is relatively easy to build, which is one big difference when the Audine system is compared to commercial cameras. To the novice, that difference may justify the difference in price between Audine or a camera bought in a shop.
The price of a brand-name camera is not only in the delivered hardware. You also pay the for the expertise and reputation of the company, a time of development, an after-sales service, and the operating expenses of the company. As you come to think to all these aspects, you understand that the prices in the shops are not so high. This is no secret: if the Audine camera is not very expensive it is because you do not pay for the development, and you do not pay for an official hot-line in the event of problem.
Most people build an Audine for the following reasons: they are not very rich, they are handy with tools and equipment, they are curious, and they are teachers. To the members of a club or a class, the Audine can make it possible to study all the aspects of obtaining an electronic image: electronics, optoelectronics, data processing, mechanics, refrigerating engineering, technology, image processing, and observation techniques.
Here is a quick summary of Audines performance:
The CCD is a Kodak KAF-0400. It has 768x512 pixels of 9 microns (the pixels are square). Sensitive surface is 6.9 X 4.6 mm (32 mm2). Digitization is on 15 bits. The reading time of a complete image is 15 seconds (binning 1x1) and 5 seconds (binning 2x2). The reading noise is lower than 20 electrons. Almost all the reading modes of the CCD are supported by Audine: full image, binning, windowing, half-frame, drift-scanning... The camera can be connected to virtually any PC computer, including lap tops, via the printer port. The Audine system is provided with acquisition software which is among the most powerful available, and... the software is completely free! The camera is compact (90 X 80 X 80 mm) and weighs 600 grams. A system with a Peltier module is used to lower the temperature of the CCD by 35°C compared to the ambient temperature. You can make images of several minutes.
To build Audine, you must have the following elements:
You must have spare time (4 to 5 evenings of work) to manufacture all the camera if you have all the required hardware.
The budget is $1,250 (including all taxes) approximately for one complete camera. If you buy the parts with other people, the total price drops (approximately $900 including all taxes). Among the parts, the price of the CCD is the highest (approximately $300). In addition,
The required electronic hardware is the following:
An oscilloscope is not essential but can help in the event of a problem.
If you are a mechanic and if you have the equipment (lathe and milling machine), you can manufacture a housing. But we have a good mechanical solution with a very low price for the spare parts.
Finally you can download various very powerful programs here to use Audine
very effectively. If you are a programmer, precise information on the operation
of Audine is also given. As such, you can develop your own programs, which we
hope will be free and widely diffused. It is the spirit of this project that
we hope this will be done.