Observing a satellite can be as easy or as difficult as you want to make it. It can be problematic when a cat licks the line you drew depicting the carefully drawn path of an upcoming satellite pass. Many satellites are able to be viewed without any optical aid, hence negating the need to use a star chart providing you have some familiarity with the night sky. Other satellites require binoculars or small telescope or even a very large one. My equipment is rather varied. The standard instrument of my choosing is 7x35mm binoculars. The following image shows the Tasco 7x35 binoculars, portable cassette tape recorder and stopwatch that I use.
For more difficult objects I use Fujinon 25x150mm binoculars, which I purchased in Japan in 1980. The mount is an alt-azimuth support scheme using a record turntable, pipes and supermarket shopping cart wheels integrated and constructed by Andy Saulietis. Folded up cardboard is used to place around part of the binoculars to help keep stray light out. However, the cardboard does have a tendency to blow down in high wind and loses its rigidity due to high humidity in the Houston, Texas area. Yet the cardboard panels are easy to set up and take down.
A light shield was constructed using the top of a copier paper box that is very useful for blocking stray light.
PHOTOGRAPHY A simple camera mounted on a tripod can capture some satellite passes using high speed film provided the speed of the satellite and its brightness are optimal. As an example, I show the following image in which the Mir Space Station, Salyut 6 Space Station and Tiros 4 (the fainter trail perpendicular to the other two) are all contained in one timed exposure that I shot from Manassas, Virginia on May 1, 1986. The film is Kodacolor 400 and a cable release was used to minimize the jitter as the shutter was opened and closed.
THE EARLY YEARS
Satellite observing was not as easy in the 1960's as it is now. For example, though computers were present, it took manual effort to use a keypunch machine in order to enter data on 80 column IBM cards.
Essentially a deck of cards was run in order to generate an output file on a ream of interconnected paper.
Even before that it was possible to get equatorial crossing times for some satellite orbits and these were in the form of hardcopies.
Small binoculars or telescopes were used more so than the larger aperture instruments of today.
VIDEO SYSTEM
Passage of a satellite can also be documented on videotape. I have used this method for more than 16 years now, and it allows me to review and replay a pass instead of rely on memory. The system consists of a camera tripod on which are mounted an image intensifier connected to a video camera. The intensifier has a Nikon mount so I can interchange objective lenses. These can range from a 300mm f/5.6 to a 8mm fisheye. Audio and video cables extend from the video camera to ports on a Sony camcorder TRV model powered by a 12-hour lithium battery. The camcorder has a very small fold-out screen, which allows me to monitor a scene proportional to the field of view output by the system. In the following images, the system is on a tripod in the first frame, and it is shown next to a briefcase which holds a short-wave receiver for time signals, a battery for powering the video camera and (not shown) the camcorder. The recording medium has changed from large VHS recorders to more compact 8mm models. I use a 2nd and 3rd generation image intensifier that is not only good for satellite tracking, but also for other astronomical applications such as occultations, variable stars and other point-source targets.You can reference SPACE EDUCATION, vol. 1, no.9, May 1985, p.415 for an article describing my early video system applications. Also see SKY AND TELESCOPE, December 1988 for the report describing our use of the Litton M911A night vision pocketscope.
The video system is used to document certain satellite passes and therefore eliminate the observer's personal equation (that is, reaction time). It is not an the ultimate system, however. The image intensifier is not sensitive to very rapid variations of light. It takes the electronics aa finite response time to catch up to what it thinks it is detecting. If a moving object has a diffuse component, the image intensifier has a very poor response to it. It is also extremely sensitive to light. Any adjacent light sources, sky back ground or proximity to twilight will adversely impact the results. Caution should therefore be used by the reader when thinking about purchasing such a system. I have had a number of spectacular failures in addition to uplifting successes in tracking earth satellites.
I use different types of star charts. My favorite is Norton's SKY Atlas. I copy the charts and take the copy with me on trips instead of the original book. Though the stars only go down to +6 on this atlas,\I can use them for observing satellites down to +10. For finer detail, I can choose from several other atlases or download Palomar Sky Atlas charts if needed.
Another component of satellite observing is the observing log. Without it you cannot really retain a good historical record of your data. The parameters I normally log are UT date, UT time, satellite catalog number, elevation, azimuth, height, slant range, phase angle, magnitude, flash or tumble period.
In addition to a stopwatch I utilize a decent digital watch that shows both local digital time and UT digital time. This watch (and the stopwatch also) has a backlit screen. To be consistent, you should have satellite predictions that are in the same time system as your watch .
A further valuable tool is a flashlight with red filter to minimize loss of dark-sky adaptation. Of course, with my residential site, this seldom provides much relief.
My observation site is located in Clear Lake City, a suburb of Houston located 25 miles southeast of central Houston and 3.5 miles from the NASA Johnson Space Center. On an average night I can see down to +3.5 magnitude naked eye. On a really good night it can drop to 4.5.