Basic AstronomyBasics about telescope and how to

view the cosmos.

Telescopes

Refractor telescopeReflecting Telescope

The 2 basics

How they work

Refractor

Pro’s & Con’s

Refracting telescopes are the most common form of the telescope - a long, thin tube where light passes in a straight line from the front objective lens directly to the eyepiece at the opposite end of the tube.Advantages* Easy to use and consistent due to the simplicity of design.* Good for distant terrestrial viewing* Excellent for lunar, planetary and binary stargazing especially with larger apertures* Sealed tube protects optics and reduces image degrading air currents* Rugged, need little or no maintenance

Disadvantages * Generally have small apertures, typically 3 to 5 inches* Less suited for viewing small and faint deep sky objects such as distant galaxies and nebulae* Heavier, longer and bulkier than equivalent aperture reflectors and catadioptrics* Limited practical usefulness* Good-quality refractors cost more per inch of aperture than any other kind of telescope.

Reflecting telescopes use a huge concave parabolic mirror instead of a lens to gather and focus the light to a flat secondary mirror that in turn reflects the image out of an opening at the side of the main tube. You look through an eyepiece on the side of the tube up near the top.Advantages * Easy to use and even construct* Excellent for faint deep sky objects such as remote galaxies, nebulae and star clusters because of their larger apertures for light gathering.* Low in optical irregularities and deliver very bright images* Reasonably compact and portable* A reflector costs the least per inch of aperture compared to refractors and catadioptrics since mirrors can be produced at less cost than lenses

Disadvantages* Generally, not suited for terrestrial applications* Slight light loss due to secondary obstruction when compared with refractors* The tube is open to the air, which means dust on the optics even if the tube is kept under wraps* Reflectors may require a little more care and maintenance

Of the basic telescopes

DO NOT LOOK AT THE SUN

• Very dangerous• Special Sun filters• Fit all size Telescopes

Without special Solar filters

How to View the SunSunspots – Magnetic storms

International Space Station - ISS

Passing in front of the Sun

Viewing the Planets

• Planets have many different magnitudes• Amazing viewing from the storm bands

around Jupiter to the rings angle around Saturn to the red of Mars and the blue-green of Uranus and Neptune

• Notice the moons around Jupiter and Saturn

Viewing Jupiter

Viewing above 45 degrees

Viewing above the horizon

To low producing fuzzy image

Viewing the Moon

• Don’t look at the Moon to long.• Look along the inside edges, you will see

better details and many more features.• Moon filters – Cut down on the brightness.

Galaxies and Nebulas

• Some of the best viewing• Plenty to look at

Messier objects

110 Galaxies and NebulasWhat are they?

Discovered by Charles Messier who was a French Astronomer in the late 18th century,most notable for publishing an astronomical catalogue consisting of deep sky objects such as nebulae and star clusters that came to be known as the 110 "Messier objects".

Messier 110

M13

M57 the Ring Nebula

M31 Andromeda Galaxy

Planets and viewing availability

• Planets can only be viewed during certain parts of the year

• As the season passes the Planets rise earlier• Best viewing time is overhead and not close to

the horizon• The atmosphere interferes with your viewing

making your image all blurry

Angles made easy

Earth is like a protractorWith 90 degrees being straight up and 0 degrees representing the horizon

Figuring the angle when looking upFully extend your arm in front of you. A fist = 10 degrees, your hand stretched out = 20 degrees

Viewing area

• What are the best conditions• Weather plays a factor• Light pollution

Viewing Tips

• Use Stars and Planets as reference points• Make sure street lights and house light are

behind you or off.• Try viewing at a higher angle, above 45

degrees.

Satellites