12-inch dome.














Seldom does a project come along that is so exciting or so innovative that people not associated with that project or field rally behind it. Such is the Hamill Observatory project being built by the Northwest Astronomy Group. Hamill Observatory will give amateurs the opportunity to have a facility to do research at a professional level from anywhere in the U.S. or Canada. The Hamill Observatory 24-inch telescope will be equivalent to a 200-inch or larger telescope. Also, currently under construction, is the Vernonia Peak Observatory which will be equivalent to a 120-inch telescope with film.

The Northwest Astronomy Group (NWAG) is a nonprofit organization that was formed in 1980 with the goal of building an observatory to be used by amateurs for both research and education. We are lucky to be in an area that has a large number of high-tech companies where we can draw on technology as well as people with backgnd that are needed to put this kind of project together. Many of the members of NWAG have either designed or helped design much of the new technology that will be used in the projects. The observatories will be available to anyone wishing to be involved in a research project. This will include schools, clubs, planetariums, and societies that are not classed as professional.

The observatories' computers and imaging equipment, including the support equipment, will be high tech. State-of-the-art communications equipment will allow users to operate the observatory and process images from their home or from local schools with a home computer and modem, or through an amateur radio station or the Internet through the astronomy groups WEB page. By adding a system developed by Ham radio operators, called packet radio (an interface between the radio and the home computer), we have a method of transmitting images and control of the observatory. Many of the high schools have ham radio stations and, with the addition of packet radio or the internet, can have access to both the Hamill 24-inch and the Vernonia Peak 14-inch telescopes. There is even a chance we will have our own communications package aboard an amateur radio geosynchronous satellite and possible access to one or two of the commercial geosynchronous satellites. This may provide an additional method of transmitting the use of the system to those who want to use it.

Many of the research projects will be coming from some of the largest astronomical institutions in the U.S. Each research project will be completed by a team using accepted scientific methods so the end result will be useful to those who need the data. This will also allow the largest number of people to use the telescopes. Many of the programs will be able to be processed with small computers at the primary school level providing a powerful tool to the educational world and giving children a chance to work on real research projects. This should make astronomy an exciting subject in both grade and high schools, as well as teaching other subjects such as computers, imaging technology, and physics.

A smaller facility next door to the future Hamill site, called the Vernonia Peak observatory. It has a 12.5-inch Newtonian telescope and will be equipped with two CCD cameras and a CCD spectrometer. (CCD stands for charged coupled device. These devices are many hundreds of times more sensitive than photographic film. Therefore, they make the most sensitive astronomical cameras. The output of a CCD camera is digitized information that a computer can process.) The first CCD camera that will be in operation will be a sensitive scanning CCD camera (like a TV camera) with a single stage microchannel image intensifier (light amplifier) that will later be used to provide accurate automatic tracking for the 12.5-inch telescope. The second camera will use a much more sensitive CCD that will be able to "expose" images somewhat like a standard film camera. This will give us more light gathering power than is possible with film. The first two cameras should be in operation by this spring and the spectrometer later this year.

The drive system for the 12.5-inch telescope will use a pair of DC motors and a drive system. This will allow reasonably fast slewing with smooth, accurate tracking without gear changes. This type of motor system is well suited for remote computer control operation. Even the dome tracking and the opening and closing of the dome doors will be done by remote computer control.

With the CCD cameras, the 12.5-inch telescope at Vernonia Peak Observatory will have a light gathering power equivalent to a 130-inch telescope, but still the resolution of a 14-inch telescope. The Hamill 24-inch telescope, however, will have a secondary mirror cut into seven segments. Six of the mirror segments will be electronically focused to produce one image referenced to the center fixed mirror. This technique will increase the resolution of the telescope by about 8-10 times. The active segmented secondary mirror makes the telescope operate as if it were in outer space by eliminating the refraction effects of the earth's atmosphere. Each segment takes a single computer to keep that mirror focused. The increased resolution and use of some of the best CCD cameras in the world will make the 24-inch telescope equivalent to more than a 200-inch conventional telescope.

Oddly enough, the major problem with building the Hamill observatory is not the mechanical aspect but the large amount of software that will have to either be modified or written from scratch. The tremendously large images produce problems in storage, processing speed, and software for processing. The smaller CCD camera produces about 600,000 bytes of data per image. That means that you can only get one image on a 720 kb (kilobyte) floppy disk.

The telescopes will produce a large number of images to be stored. Even the 14-inch telescope, when tracking an object for as little as 1 to 1 1/2 hours, will easily digitize images below 23rd magnitude. So one night's operation could, with brighter magnitudes, produce 20 images or more. A larger CCD camera, which will be used on the 24-inch telescope, only makes these problems more difficult because it will produce more than ten times the data of the smaller camera. The reason the CCD's produce so much data is because of their tremendous dynamic range. Each pixel of the camera produces 64,000 possible levels of gray scale. (A pixel is one cell in an image. For example, there are approximately 250,000 pixels in a black and white television set.) That works out to be a lot of data. Fortunately, technology has come to the rescue. With the advent of laser disk storage, 200 to 1000 images can be stored on one laser disk depending on which camera is used. This also provides easy access to a large number of images by the users so that many projects can be going on at one time.

Now, how will all this work? Starting with the 12.5-inch telescope, one computer will keep track of the star charts, another will deal with telescope control and tracking, yet another will deal with image storage and processing. A central computer will take care of these other computers, as well as communications with the packet radio, telephone modem and, later on, other communication ports. With the 24-inch telescope there will be 12 different computers to make up the full system. The next problem is, how can images that large be transmitted in a reasonable amount of time? The answer is, they can't. So, the images have to be reduced to cut down the transmission time from 10 to 15 minutes or more to under 2 minutes. Also, another reason for reduction, is that home computers can't handle the large images. After the reduced image is received, the user will be able to further process the images on their home computer. If the information is not what was wanted, then they can have the larger computers at the observatory site reprocess the image and transmit a new image to be further processed. After the data has been extracted from the images, it can then be stored in the observatory's computer for use by the rest of that team as well as other users.

All this may sound very complicated, but to the user it will be easy to access and run. Even a person with little computer experience should have no problem with the system.

The project is a big one and we are actively seeking support. If you have questions or comments write or e-mail to: Sandy Mikalow

      The Northwest Astronomy Group, 55371 McDonald Rd., Vernonia, OR 97064.

We hope to complete this project in the late 1990's. In the meantime, I'm sure that many will want to be involved with a 14-inch telescope that is equivalent to 120 inches in light gathering power. Who knows, maybe you or your children will be the discoverer of a new supernova in a distant galaxy.

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Vernonia, Oregon 97064
Tel: (503) 429-2430
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