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Appendix E: YOU AND THE UNIVERSE

APPENDIX

E

The distance from the Earth to the Moon

Radius = 239,000 miles

The distances between the planets

The distance from the Earth to the Sun is 93 million miles or 1 Astronomical Unit (AU)

Pluto’s elliptical orbitis eccentric and carriesthe planet inside theorbit ofNeptune at itsclosest approachto theSun.

The distance between stars

The distance from the Sun to the nearest star is about 4.3 light-years, or 25 trillion miles. This distance is so large that if a scale model were created with the Earth one inch away from the Sun, the nearest star would have to be placed over 4 miles away!

Approximately one hundred billion stars, including the Sun, comprise the Milky Way Galaxy, which is a spiral-shaped

collection of stars believed to be more than 100,000 light years in diameter.

The distances between galaxies

Milky Way Galaxy

Andromeda Galaxy (M31)

Whirlpool Galaxy (M51)

The Sun

2.2 million light-years

 

35 million light-years

 

 

 

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Meade ETX-90EC instruction manual Distances between the planets, Appendix E YOU and the Universe

ETX-90EC specifications

The Meade ETX-90EC is a compact, portable telescope that has garnered significant attention among amateur astronomers for its exceptional optical performance and user-friendly design. Launched as part of Meade's popular ETX series, this telescope blends advanced technology with accessibility, making it an ideal choice for both beginners and experienced users.

One of the standout features of the ETX-90EC is its Maksutov-Cassegrain optical design. This design incorporates a spherical primary mirror and a corrector lens which contributes to sharp images with minimal optical aberrations. The 90mm aperture allows users to observe a variety of celestial objects, from the craters on the Moon to distant galaxies, while maintaining a compact form factor. The telescope's focal length of 1250mm provides a substantial level of magnification, enabling users to enjoy detailed views of planets and other astronomical phenomena.

The ETX-90EC boasts a robust computerized system, powered by Meade's Audio Star technology. This feature not only assists users in locating over 30,000 celestial objects with just a few simple commands, but it also provides educational audio information about these objects, enhancing the observational experience. The telescope's GoTo capabilities allow it to automatically point to selected objects, transforming the stargazing process into an interactive and informative experience.

Another significant aspect of the ETX-90EC is its portability. Weighing in at under 10 pounds and featuring a foldable design, this telescope is easy to transport and set up in various locations. This makes it ideal for both backyard astronomy and travel to darker skies where light pollution is minimal.

The ETX-90EC also incorporates an electronic drive system that ensures smooth and precise tracking of celestial objects, which is invaluable for astrophotography enthusiasts. With optional accessories, users can attach cameras and other devices to capture stunning images of deep-sky phenomena.

Overall, the Meade ETX-90EC combines advanced optics, user-friendly technology, and portability, making it a versatile and powerful tool for exploring the night sky. Whether you are a novice looking to kickstart your journey into astronomy or a seasoned observer seeking a reliable companion, the ETX-90EC offers a unique blend of performance and convenience that appeals to a wide range of stargazers.