GPS Telescopes: How to Make Stargazing Easier
Humans have been gazing up at the stars in the night sky since the beginning of time. At first, people merely used their own eyesight to watch the stars. Soon, they began to long for a better way to view the night sky. Hans Lippershey provided that better way when he invented the telescope. (There is debate about exactly who invented the telescope. Lippershey is credited with the invention because he applied for the patent in 1608). Galileo, however, is the man credited with bringing stargazing to the forefront. He built his own refractor telescope (the simplest telescope made from two lenses and a tube), specially adapted for studying the heavens.
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Since Galileo’s time, the telescope has evolved from a simple narrow tube with two lenses into a complex, computerized instrument. These computerized telescopes, often called “go-to” or GOTO telescopes, offer precise motor control, excellent optics, and position sensors. With these telescopes, the user can view planets, galaxies, stars, and other objects by simply pushing a few buttons. Add a GPS receiver to this computerized instrument and you get the latest technological advancement: GPS telescopes.
GPS (Global Positioning System) is a network of 24 orbiting satellites that was established by the U. S. Department of Defense. These satellites orbit the earth twice a day and continuously transmit radio signals. The GPS receiver uses these radio signals to determine the user’s geographic location (calculating latitude, longitude, and altitude.) To perform this determination, the receiver must be locked on to the signal of three satellites.
In order for a GOTO telescope to be accurately set up, it must first be aligned with two known positions (stars) in the sky. Once the telescope has this information it can create a model of the sky, which it uses to locate any object with known coordinates. The user will need to input simple information such as date, time, and location.
With GPS telescopes, the user no longer has to worry about the date, time, latitude, and longitude, or looking up coordinates on a chart. Aligning the telescope is quicker and easier.
The latest versions of GOTO telescopes offer GPS as part of the package. For astronomers who don’t want to buy a new telescope, GPS data is available in another way, a portable GPS receiver such as the StarGPS. This receiver is smaller than a computer mouse, and connects via a cable to the telescope. This particular receiver is compatible with any 495/497 Autostar controlled telescope, such as the Meade LXD55/75, LX90 and ETX series. StarGPS includes two other versions of receivers, the StarGPS-NX and the StarGPS-NX01. These two receivers are compatible with a wider range of telescopes. Cost for these adapters run between $100 and $200.
Another way to add GPS to a telescope is through an adapter such as the StarDate™ GPS adapter. This adapter allows users to connect any NMEA-0183 compliant GPS receiver to any Celestron telescope equipped with an AUX port, including NextStar 5i/8i Series and the CGE series. Cost is under $100.
For those who prefer purchasing a telescope with the receiver already embedded in the instrument, a high-end option is offered by Celestron. This telescope is a diffraction limited Schmidt-Cassegrain telescope and costs around $3000. The CPC 1100 has an 11 inch lens and a database of over 40,000 objects. In addition, the “Hibernate” feature allows the instrument to maintain its star alignment for several nights, eliminating the need for realignment.
Meade. These telescopes feature a coma-free field similar to that of the Ritchey-Chrétien design and are available in 8, 10, and 12 inch apertures. The LX90-ACF series are also equipped with a Sony® GPS sensor and Meade’s AutoAlign feature, which means the telescopes come pre-aligned aligned right out of the box. Prices for this series range from $2,000 to around $4,000 depending on aperture.
GPS telescopes are truly innovative with their embedded GPS and computerized controls, but may not be for everyone, especially novice astronomers. Cost is a factor, obviously, but so is the technology. These telescopes may take longer to set up, may be heavier than their lower-tech counterparts, and do require some understanding of astronomy and some knowledge of the sky. Be sure to research the features and how those features fit the needs of the observer before making a purchase.
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