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Observation suggestions

The Moon:
Diameter: 3,476 km
Distance: Approximately 384,401 km
The Moon is the Earth’s only natural satellite, and it is the second brightest object in 
the sky (after the Sun). Although it is our closest neighbor, a lot of people have never 
really taken a good long like at the Moon. With your telescope, you should be able 
to see the intricacies of the lunar terrain — including lunar maria, which appear as 
vast dark plains, craters and rilles. The best views will be found along the terminator, 
which is the edge where the visible and cloaked portions of the Moon meet.

Planets
The planets are continuously changing their position in the sky, so it may help to 
consult online resources to determine the correct place to look on any given night. 
The following planets are especially suited for observations with a Dobsonian 
telescope.  

Venus
Venus is the third brightest object in the night sky, which makes it an ideal observing 
target. The diameter of Venus is about 9/10th the diameter of the Earth. Viewing 
Venus at different times in its orbit will reveal different phases (crescent, half and 
full) much like the phases of our Moon. The planetary disc of Venus appears white 
because the sunlight is reflected by a compact layer of clouds that covers all surface 
details.

Mars
The diameter of Mars is about half that of the Earth's diameter. It will appear as a 
red-orange disk, which may exhibit small white patches near the polar regions. 
Observing Mars when it is closest to the Earth will show even more details, so it is a 
good idea to consult online resources to determine when those dates might occur. 

Jupiter
Jupiter is the biggest planet in our solar system and is the fourth brightest object in 
the night sky. The equatorial diameter of this gas giant is 11 times bigger than that 
of the Earth. Through the telescope, you should be able to see the cloud bands in 
the atmosphere of Jupiter and the Great Red Spot. Even with low magnification, you 
will be able to see the four Galilean moons — Io, Ganymede, Europa and Callisto — 
as they march across the face of Jupiter. You might also be able to pick out some of 
the many smaller moons of Jupiter. 

Saturn
Saturn is a dynamic sight when viewed through a telescope. It will appear as a 
round disc surround by its distinct ring structure. The rings of Saturn mainly consist 
of billions of icy particles ranging from dust up to chunks that size of a house. 
The Cassini division, which is a large gap in the rings, might be visible from your 
telescope. You will also be able to see the largest of Saturn's moons — Titan — and 
possibly others. 

Deep sky objects
There are several types of deep sky objects that make excellent observing targets. 
To locate specific targets it is important to have a star chart and be familiar with the 
constellations. The following are types of deep sky objects that you can observe: 

• Stars are giant objects that mainly consist of gas. They radiate energy and shine 
because of nuclear fusion going on in their core. Due to the fact that star are 
extremely far away, they appear as points of light both to the unaided eye and in 
telescopes. However, with a telescope, you might be able to view separate members 
of binary or multi-star systems. 

Fig. 16: Craters of the moon are excellent targets to 
observe even for beginners.

Fig. 17: Planet Venus in its thin crescent phase

Fig. 18: Jupiter's four largest moons can be observed in a
different position every night.

Fig. 19: Saturn is perhaps the most unforgettable sight to 
see in a telescope.

Usage

Summary of Contents for Explore FirstLight 10" f/5 Dobsonian

Page 1: ...cope models can appear daunting they can be broken down and transported easily even in small cars and reassembled within minutes The FirstLight series includes two Dobsonian models 8 and 10 Each comes...

Page 2: ...n optics after you have removed as many particles as possible with forced air or a photographic grade camel hair brush DO NOT use optical lens cleaning tissues as many contain fiberglass particles tha...

Page 3: ...3 A D C F E B G H I J K 10x L 10x M 5x N 1x O 1x P 2x Q 2x R Fig 1 3x S 4x T U Package Contents I...

Page 4: ...4 Parts Overview II Fig 2 Inset A Inset B 1 3 5 4 2 6 7 8 9 10 11 18 19 20 20 20 21 21 21 12 13 14 16 16 14 a 15 17...

Page 5: ...dge 9 Base side parts 2x 10 Base front part 11 Round base plate 2x 12 Rubber feet 3x Eyepiece holder Inset A 13 Focusing drive 14 Friction screws Focus lock and grinding pressure adjustment 14a Fixing...

Page 6: ...bottom plates Fig 1 A B 2 Screw four threaded bolts Fig 1 L into the outer drill holes of bottom plate on top 3 Put both bottom plates on top of each other 4 Bolt both bottom plates together with the...

Page 7: ...he remaining threaded bolts Fig 1 L of the bridge Fig 1 E and the front part Fig 1 F 2 Tighten the quick fasteners with a Phillips screwdriver 3 Use two woodscrews Fig 1 N to attach the accessory tray...

Page 8: ...tion of the front part Fig 11 10 when attaching it 2 Hold the OTA with one hand until it is balanced correctly If neccessary move the OTA a little to another position within the brackets Fig 11 5 to e...

Page 9: ...ng a spacer sleeve it is also no longer necessary to turn out the eyepiece extension until it stops It also increases mechanical stability 1 Unscrew the eyepiece holder Fig 12 2a and remove it from th...

Page 10: ...tice at first but you ll soon get the hang of it Be sure the mount is placed on a relatively level surface to allow proper operation Each of the three feet should be in firm contact with the surface a...

Page 11: ...accidentally point your telescope at or near the Sun see Sun Warning in this Manual After you have set up your telescope and attached the red dot viewfinder find an easy stationary target that is at...

Page 12: ...net in our solar system and is the fourth brightest object in the night sky The equatorial diameter of this gas giant is 11 times bigger than that of the Earth Through the telescope you should be able...

Page 13: ...new stars are born The premier nebula on the northern hemisphere is the Great Orion Nebula Orion Nebula Right ascension 05 35 4 hours minutes Declination 05 27 degrees minutes Distance Approximately 1...

Page 14: ...jectsthatareclosetothehorizonareseverelyinfluencedbyairturbulence and absorbance It is much better to time your observations in a way that those objects are close to the meridian so that they are at t...

Page 15: ...focuser tube and the observer s eye appear centered relative to each other However with the short focal ratio primary mirror of this Dobsonian telescope correct collimation requires that the diagonal...

Page 16: ...main telescope s field of view 5 Bring the star s image slowly in and out of focus until you see several disks surrounding the star s center If steps 1 through 3 were done correctly you will see conc...

Page 17: ...ter 254mm 10 Secondary mirror obstruction 24 Focal length 1270mm Focal ratio f 5 Theoretical resolving power 0 59 arc seconds Limiting magnitudes 14 mag Focuser 2 5 Hex focuser with 2 and 1 25 adapter...

Page 18: ...when possible Contact your local waste disposal service or environmental authority for information on the proper disposal Please take the current legal regulations into account when disposing of your...

Page 19: ...19...

Page 20: ...2018 Explore Scientific LLC 1010 S 48th Street Springdale AR 72762 explorescientificusa com exploreone com 866 252 3811 All rights reserved Made in China Rev 02 19 2018...

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