Operating System and Equipment - Part 2
Section II: Facilities
B. Operating System and Equipment - Details, continued
Charge Couple Device (CCD)
What is a CCD?
Now, amateurs can observe distant stars and celestial objects with much greater comprehension and appreciation than was possible less than 20 years ago. Estimates of age, mass, distance and material makeup require accurate intensity and chromaticity measurements. The beautiful, true colors of distant galaxies, nova, nebula and dust clouds can now be seen. These capabilities are all possible with the addition of a CCD to the telescope system.
What is a CCD? It is an electronic detector. The heart is a tiny silicon chip with a typical working area of less than 1/4" inch square. If an optical image is formed on one side of the chip, electron charges, exactly proportional to the light (photon) intensity are produced on the other side of the chip. Those charges can then be manipulated and converted to form an electronic image of the light image in a device such as a computer.
Millions of people use them on their video cameras without giving them a thought. Designed and adapted to astronomy, however, many wonderful things as listed above can be done with them.
Features of the CCDs that are significant and useful in a telescope system:
- Each image element of the CCD is much more sensitive to light than either the human eye or photographic film.
- The image can accumulate electron charges much more effectively than photographic film, and incredibly more effectively than the human eye. Charge images in each elemental area are generated exactly proportional to the product of light intensity x time over a far greater range than the equivalent for either film or retina. Thus the device lends itself to all types of quantitative analyses far more effectively than either of the other approaches.
- Not only the total number of charges in each position is known, but also its location, in xy coordinates, can be determined electronically. This simplifies mapping problems considerably, and the data can also be used in near real time to generate tracking signals in a straightforward manner impossible for the other two techniques.
- Inherent electronic noise is made nearly negligible by cryogenic cooling, and zero level offsets for each picture element can be individually corrected by a relatively simple procedure.
- The unit is compact, and the readout is remote.
- Finally, the precision electronic images thus produced can be stored, collated, manipulated and transmitted to other locations with no loss of fundamental accuracy. Remote viewing as well as detection and control, are now practical.
- The CCD can be used as a sensor of high resolution, accuracy and throughput for spectrometry.
- CCD camera operation is planned enabling the viewing to be done inside the building from the control room. The operation of the scope can be totally controlled from this room. One does not have to get cold or heat up the telescope. Incidentally there are some clear January nights. Access to an actual eyepiece, however, will be provided for those who want the thrill of looking through a large telescope first hand.
We now have one CCD ready for use and one complete set of parts for a second unit.
Plans and Use
Our intention is to have a planetarium set up inside the Helix House. The projection equipment would be set up and groups of students or the public could be brought into the building and given instruction in astronomy, geography, plate tectonics, and other subjects. One piece of equipment we are considering has 12 different cylinders showing various celestial and geographic sources of information.
In addition, the unit package includes an inflatable dome that can be set up at various places to present the same demonstrations. We anticipate using the system at both Bainbridge Island schools and other schools in the area.
It is an investment that can actually be self supporting if schools are willing to pay for the "star show" to augment their science programs.
Another way the equipment can be used is to show stars, planets and the sun and moon in the planetarium, together with projections of photographs of various celestial bodies through very large telescopes, as well as to train our telescopes mounted on the roof overhead to focus on an object in the sky of particular interest and have it displayed on a monitor immediately, amplified through the use of the charge couple device (CCD) mounted on the telescope (as previously described).
We believe that the CCD telescope and planetarium are an outstanding teaching combination that may well stimulate students to learn more about the cosmos in which we live. We hope that some young people will be inspired to take up scientific pursuits and contribute to our knowledge of our universe during the course of their lifetime.
How can a planetarium be used?
The planetarium has four basic uses:
- To provide astronomical awareness to young and old by acquainting the viewer with the patterns and movement of various celestial bodies, as well as the positions and names of the important stars and constellations, including classical, Chinese and American Indian constellations and legends. Also, teaching the viewer about longitude, latitude, seasonal changes and long time changes such as 26,000 year precession cycle and the 18.61 Metonic moon cycle, through the basic movement of the earth, both rotation and orbital. The viewer can be given a basic understanding of the solar system.
- To provide a direct aid to the use of the observatory, by identifying and showing slides of the objects that will be seen through the large telescope; giving instruction on the use of the star map, and the difference between location of the celestial objects by "star hopping" versus using right ascension and delineation; giving instruction on the difference between old and young stars.
- To assist archeological astronomy by rolling back time, providing an awareness of Chinese and American Indian constellations and legends.
- To provide a fill-in for observatory public users by providing a backup presentation in case of denied real time viewing; educating and entertaining people who are waiting to use the telescope.
A student who is exposed to the knowledge that we can dramatically impart will have a better appreciation of the miracle in which we live and will be much better equipped to live in the time of greater utilization of and exploration of our greater environment. Our hope is that others will be made aware and will ultimately participate in astronomy.
Relaying and Remote Access
The BPAA is intended to be part of an international network, connected by conventional and electronic mail to provide data transfer, communication, conferences, and publication distribution. Amateur astronomy is, at heart, an individual activity, but those involved in serious work "climb on the shoulders" of the collective and documented work of thousands of others, and appreciate the need to share so that the science can flourish.
Viewing in one location is limited by latitude, cloud cover, and local time of day. Remote viewing allows another area of the celestial sphere to be seen and a continuous study of one celestial object can be continued "beyond the horizon" or after sunrise or before sunset. Cloud cover is most annoying to continuous viewing, and anther site with telescopes owned and operated either by us or by others a few hundred miles away can provide the data that fills in the gap. This transfer is not as difficult as it might appear, as star field data is "sparse" and the data of a field can be compressed without loss of essential content or resolution.
Finally, things can happen in a hurry, which requires immediate contact with all members. E-mail provides the means to alert all of our members that a celestial (or financial) event is suddenly upon us.