GEO77

COMPACT 144mm

ASTRONOMICAL REFLECTOR TELESCOPE

INSTRUCTION MANUAL

TELESCOPE CONTROLS

     The GEO77 telescope comes equipped with two important controls which you should become acquainted with before attempting observations through the telescope.

Focus Knob

(5, fig. 1) Turning this knob finely moves the telescope’s eyepiece to achieve precise focus of the image. Rotate the focus knob clockwise to focus on distant objects; rotate the focus knob counterclockwise to focus on near objects.

Secondary Mirror Collimation Screws

(6, fig. 1) There are three screws in the centre of the front main lens of the telescope tube. These screws adjust the angle of the secondary mirror, which changes the light path to the focuser (4, fig. 1). If you suspect an alignment problem contact mqp customer service advice.

MAGNIFICATION

     Magnification, or power, is determined by two factors: the focal length of the telescope and the focal length of the eyepiece used.

Telescope Focal Length

     Generally speaking, telescope focal length is the distance that light travels inside the telescope before reaching a focus. In the mirror-lens design of the GEO77, however, this focal length is, in effect, compressed by the telescope’s secondary mirror, so that a long effective telescope focal length is housed in the short GEO77 optical tube.

Eyepiece Focal Length

     The eyepiece focal length is the distance light travels inside the eyepiece before reaching focus. Your Canadian Geographic GEO77 comes with 6.5mm and 25mm Plossl eyepieces as standard equipment. “Plossl” refers to the optical design of the eyepiece, a 4 lens element design. The focal length for any eyepiece is generally printed on the side of the eyepiece.

Calculating Magnification

     On telescopes, such as the GEO77, different eyepiece focal lengths are used to achieve different magnifications, from low to high. The standard equipment PI25mm eyepiece, as stated above, yields 22X. To calculate the magnification obtained with a given eyepiece, use this formula:

                               Power = Telescope Focal Length

                                              Eyepiece Focal Length

Example: The power obtained with the GEO77 with the 25mm eyepiece is:

                              Power = 550mm

                                             25mm   = 22X

     Your new telescope also comes equipped with a 2x Barlow. When this is added to your eyepiece, it doubles the magnification.

     Overpowering the telescope is a common mistake made by beginning observers. It is wise to use the lowest magnifications which the telescope’s aperture and typical atmospheric conditions can support, and then increase the magnification until it is difficult to get a clear image.

USING YOUR TELESCOPE

     To maximize the usage of your new telescope, it is best to find the darkest possible site with fewest numbers of obstructions (such as trees). It is also a good idea to stay out of the line of sight of bright street lamps and other bright security lights. In addition, you may wish to predetermine the objects you want to see before you head outside.

There are three ways that you can use your GEO77 Telescope:

1.      With the telescope on top of a support base on a flat surface

Find a flat surface on the ground, a bench, or a flat table and put your telescope on it. Remove the front dust cover and point to the object to view.

2.   With the telescope on top of a support base mounted on a tripod

Find a level surface and adjust the height of the tripod so that the height of the eyepiece at the zenith (when the telescope is pointing directly overhead) will be at a comfortable height. Remove the front dust cover and point to the object to view.

3.   Using the neck strap onto the telescope supported in your lap

Clip the neck strap onto the telescope’s attachment points so that the neck strap will fit around the back of your head and across your shoulders. Find a comfortable location to sit. Remove the front dust cover and point to the object to view.

OBSERVING

Astronomical Observing

     Understanding how and where to locate celestial objects, and how those objects move across the sky is fundamental to enjoying the hobby of astronomy. It is advised that you purchase a book from your local book store or Astronomy specialty shop describing how to use star charts. This section provides a basic introduction to the types of objects associated with astronomy.

What To Look For In The Sky

WARNING: DO NOT AIM YOUR TELESCOPE AT THE SUN OR ANYWHERE NEAR THE SUN! INSTANT AND IRREVERSIBLE DAMAGE CAN OCCUR, INCLUDING BLINDNESS!

DO NOT LET CHILDREN USE ANY TELESCOPE WITHOUT ADULT SUPERVISION AT ANY TIME THE SUN IS ABOVE THE HORIZON.

There is a whole universe of objects to be seen in the night sky so where does one start? Well let’s examine the most visible objects first.

The Moon

The moon is the easiest target to find in the night. When it is in the full position, when the entire face is lit, then it bathes the night with a silvery light washing out the rest of the sky from all but the brightest objects. The best time to view the moon is actually not when it is full but rather anytime up to the first quarter. This is when the face appears to be half lit up. The terminator on the moon, the dividing line between the dark and light, shows the best features such as craters and mountains.

The Planets

The planets are our solar system companions. This range in size from the moon rocky bodies to giant gas balls which contain could hold 1000 earths. To find the planets require some information as to when they are visible. An astronomy magazine such as SkyNews or Sky and Telescope, will give you the locations of the planets from month to month. Most people who have looked up at night have probably seen some planets but did not realize it. A planet when it is well clear of the horizon will not twinkle as do the stars. They are resolved by the eye as a tiny ball as opposed to the stars which are infinitely small points of light. The easiest planets to view, when they are visible, are Venus, Mars, Jupiter, Saturn, Uranus and Neptune. Mercury is an object to look for but it is usually below the horizon and often is a challenge to find. Pluto is too small for most telescopes below 10” so do not worry about finding it at this time.

Each of the planets has its own interesting view. Venus is covered with clouds so all we see is an extremely bright light, the brightest light next to the moon. However, it, like our moon, goes through phases. In other words the planet surface will, as it travels around the sun, appear to have different amounts of its surface lit up. This gives the planet varying crescent shapes, as if a bite were taken out of it. Mars is the red planet. It is very noticeably red when rising above the horizon and stands out like a beacon in the night sky. The apparent brightness of Mars varies as the planet orbits around the sun so throughout its time being visible to us it will brighten and dim depending on how our two planets are aligned relative to each other.

Jupiter is the largest planet in our solar system. It is the next brightest object to Venus. Jupiter also has moons of which four are easily visible through a telescope. In fact as you watch them throughout the evening you will see that they change their positions relative

to each other and to Jupiter. It is possible with careful planning to actually see one of the moons disappear either in front of or behind Jupiter as it travels around the planet. Another great feature of Jupiter is the cloud belt pattern. Jupiter is alive with weather activity and the planet’s clouds have formed in time into belts which are visible to telescopes, when our skies allow it.

Saturn, the second largest planet, is not as bright as Jupiter and its moons are not as visible through small telescopes. However it has very large rings that encircle the planet which is spectacular. The planet appears as a pale yellow as do the rings, but one can spend hours looking at these. The major division in the rings, the Cassini division, is possible to see in a small telescope if the viewing is steady.

Uranus and Neptune are the last of the solar system gas giants. They do not yield up spectacular sights like Jupiter and Saturn; however they are part of our family and rewarding to see as they can be a challenge to find.

Beyond our solar system there lies a multitude of objects to be found. Galaxies, nebulae and star clusters abound.

TELESCOPE MAINTENANCE AND SERVICING

General Maintenance

The GEO77 Telescope is a precision optical devices designed to yield a lifetime of rewarding experiences. Given proper care and handling, the GEO77 will rarely, if ever, require factory servicing or maintenance. Maintenance guidelines included:

1. Avoid cleaning the telescope’s optics: a little dust on the front surface of the telescope’s correcting lens causes virtually no degradation of image quality and should not be considered reason to clean the lens.
2. When absolutely necessary, dust on the front lens should be removed with gentle strokes of a camel hair brush or blown off with an ear syringe (available at any pharmacy).
3. Organic materials (e.g. fingerprints) on the front lens may be removed with a solution of 3 parts distilled water to 1 part isopropyl alcohol. You may also add up 1 drop of biodegradable dishwashing soap per pint of solution. Use soft, white facial tissues and make short, gentle strokes. Change tissues often.

CAUTION: Use of improper material could result in damage to the optics.

4. If the GEO77 is used outdoors on a humid night, water condensation, “dew” on the telescope surfaces will probably result. While such condensation does not normally cause any damage to the telescope, it is recommended that the entire telescope be wiped down to dry cloth before the telescope is packed away. Do not, however, wipe any of the optical surfaces. Rather, simply allow the telescope to sit for some time in the warm indoor air, so that the wet optical surfaces can dry unattended.

Storage And Transport

It is best to store the telescope in its original box or a padded case designed for telescope storage. Store the telescope in a cool, dry place when not in use. Do not expose it to excessive heat or moisture. When transporting the telescope, take care not to bump or drop the telescope; this can damage the optical tube and/or the mirror.

Troubleshooting

Sometimes difficulties arise when trying to observe. Please proceed with the following suggestions to attempt to resolve the issues as you find them:

1. Confirm that all the lens covers have been removed from the telescope.
2. Select a large object to view (such as the moon) and focus on it – it may take several attempts to achieve sufficient proficiency in aiming the telescope.
3. An inability to focus clearly could be a collimation problem – please call our service department if you suspect this.
4. To obtain a sharp focus it is necessary to minimize atmospheric conditions. The inside of your house or building may distort terrestrial or celestial images and make it difficult, if not impossible for a clear view. For best viewing, use the telescope outside in the open air instead of observing through an open or closed window. In addition to the outside atmospheric interference, the heat within your telescope also can cause problems. To provide the sharpest image the optics must first “cool down”, simply by setting your telescope outside for 10 to 15 minutes before you begin observing should equalize the temperature of your telescope to the outside air.