background image

 

 

14 

 

 

 

Figure 5-1 

 

 
Star hopping will take some getting used to and objects that don’t have stars near them that are visible to the naked 
eye are challenging.  One such object is M57 (Figure 5-2), the famed Ring Nebula.  Here's how to find it: 
 
1.

 

Find the constellation of Lyra, a small parallelogram visible in the summer and fall months.  Lyra is easy to pick 
out because it contains the bright star Vega. 

 
2.

 

Start at the star Vega—Alpha (

α

) Lyrae—and move a few degrees southeast to find the parallelogram. The four 

stars that make up this geometric shape are all similar in brightness, making them easy to see. 

 
3.

 

Locate the two southernmost stars that make up the parallelogram—Beta (

β

) and Gamma (

γ

) Lyra. 

 
4.

 

Point about halfway between these two stars. 

 
5.

 

Move about 

½

° toward Beta (

β

) Lyra, while remaining on a line connecting the two stars. 

 
6.

 

Look through the telescope and the Ring Nebula should be in your field of view.  The Ring Nebula’s angular 
size is quite small and difficult to see. 

 
7.

 

Because the Ring Nebula is rather faint, you may need to use “averted vision” to see it.  “Averted vision” is a 
technique of looking slightly away from the object you’re observing.  So, if you are observing the Ring Nebula, 
center it in your field of view and then look off toward the side.  This causes light from the object viewed to fall 
on the black and white sensitive rods of your eyes, rather than your eyes color sensitive cones.  (Remember that 
when observing faint objects,  it’s important  to  try to observe from  a dark location, away from  street and city 
lights.    The  average  eye  takes  about  20  minutes  to  fully  adapt  to  the  darkness.    So  always  use  a  red-filtered 
flashlight to preserve your dark-adapted night vision).  

 

These two examples should give you an idea of how to star hop to deep-sky objects.  To use this method 
on other objects, consult a star atlas, then star hop to the object of your choice using “naked eye” stars. 

 

 

 

Figure 5-2 

 
 

 

 

 

LYRA 

 

 

 

 

 

 

 

VEGA 

 
 
 
 
 
 

 

The Ring Nebula 

Summary of Contents for 21035 Travel Scope 70

Page 1: ...Travel Scope Travel Scope Instruction Manual Instruction Manual Model 21035 Travel Scope 70 Model 21035 Travel Scope 70 Model 21038 Travel Scope 50 Model 21038 Travel Scope 50 ENGLISH ...

Page 2: ...rscope 7 TELESCOPE BASICS 8 Focusing 8 Calculating Magnification 8 Installing Using the Barlow Lens 8 Determining Field of View 9 General Observing Hints 9 ASTRONOMY BASICS 10 The Celestial Coordinate System 10 Motion of the Stars 11 CELESTIAL OBSERVING 12 Observing the Moon 12 Observing the Planets 12 Observing the Sun 12 Observing Deep Sky Objects 13 Seeing Conditions 15 TELESCOPE MAINTENANCE 16...

Page 3: ...before embarking on your journey through the Universe It may take a few observing sessions to become familiar with your telescope so you should keep this manual handy until you have fully mastered your telescope s operation The manual gives detailed information regarding each step as well as needed reference material and helpful hints to make your observing experience simple and pleasurable as pos...

Page 4: ...r 1 Objective Lens 7 Pan Handle Altitude Motion 2 Telescope Optical Tube 8 Tripod 3 Finderscope Bracket 9 Central Column Locking Knob 4 Erect Image Diagonal 10 Azimuth Locking Knob 5 Eyepiece 11 Tripod Head Platform 6 Focus Knob 1 2 11 10 9 3 4 5 6 8 7 ...

Page 5: ...ght you desire At the lowest level the height is about 16 41cm and extends to about 49 125cm 4 To raise the height of the tripod you unlock the tripod leg lock clamps at the bottom of each tripod leg Figure 2 4 by opening the clamp for each section by pulling outward Once a clamp is unlocked then pull the tripod leg out as far as it will go and then close the leg lock to secure it Continue doing t...

Page 6: ...tach securely the platform to the telescope optical tube 5 You can put the x 20 screw into either of the threaded holes of the Travel Scope 70 it doesn t matter which one you use in the mounting bracket of the telescope optical tube whereas the Travel Scope 50 has only one threaded hole Hold the optical tube with one hand while threading the screw clockwise until tight with the other hand Now the ...

Page 7: ...talling the Finderscope Installing the Finderscope Travel Scope 70 Travel Scope 70 only only To install the Finderscope 1 Locate the Finderscope it will be mounted in the Finderscope bracket see Figure 1 1 2 Remove the knurled nuts on the threaded posts on the telescope tube see Figure 2 14 3 Mount the Finderscope bracket by placing it over the posts protruding from the optical tube and then holdi...

Page 8: ...e skies has a limit to the highest useful magnification The general rule is that 60 power can be used for every inch of aperture For example the Travel Scope 70 is 2 8 inches in diameter Multiplying 2 8 by 60 gives a maximum useful magnification of 168 power Although this is the maximum useful magnification most of your observing will be done at low powers which generate brighter and sharper image...

Page 9: ...produces a linear field width of 131 feet at a distance of one thousand yards General Observing Hints General Observing Hints When using any optical instrument there are a few things to remember to ensure you get the best possible image Never look through window glass Glass found in household windows is optically imperfect and as a result may vary in thickness from one part of a window to the next...

Page 10: ...ines of declination are named for their angular distance above and below the celestial equator The lines are broken down into degrees minutes of arc and seconds of arc Declination readings south of the equator carry a minus sign in front of the coordinate and those north of the celestial equator are either blank i e no designation or preceded by a plus sign The celestial equivalent of longitude is...

Page 11: ...the sunlight during the day washes out the starlight However part of this circular motion of stars in this region of the sky can be seen by setting up a camera on a tripod and opening the shutter for a couple hours The timed exposure will reveal semicircles that revolve around the pole This description of stellar motions also applies to the southern hemisphere except all stars south of the celesti...

Page 12: ...ars can reveal a host of surface detail and one if not both of its polar caps You may be able to see the cloud belts of Jupiter and the great Red Spot if it is visible at the time you are observing In addition you will also be able to see the moons of Jupiter as they orbit the giant planet Saturn with its beautiful rings is e visible at moderate power Planetary Observing Hints Remember that atmosp...

Page 13: ...uide you to an object For successful star hopping it is helpful to know the field of view of you telescope If you re using the standard 20mm eyepiece with the Travel Scope 70 your field of view is approximately 2 5º or so If you know an object is 3º away from your present location then you just need to move a little more than one field of view If you re using another eyepiece then consult the sect...

Page 14: ...Nebula should be in your field of view The Ring Nebula s angular size is quite small and difficult to see 7 Because the Ring Nebula is rather faint you may need to use averted vision to see it Averted vision is a technique of looking slightly away from the object you re observing So if you are observing the Ring Nebula center it in your field of view and then look off toward the side This causes l...

Page 15: ...round major urban areas LPR filters enhance deep sky viewing from light polluted areas by blocking unwanted light while transmitting light from certain deep sky objects You can on the other hand observe planets and stars from light polluted areas or when the Moon is out Seeing Seeing conditions refers to the stability of the atmosphere and directly affects the amount of fine detail seen in extende...

Page 16: ...alcohol mixed with distilled water The solution should be 60 isopropyl alcohol and 40 distilled water Or liquid dish soap diluted with water a couple of drops per one quart of water can be used Occasionally you may experience dew build up on the optics of your telescope during an observing session If you want to continue observing the dew must be removed either with a hair dryer on low setting or ...

Page 17: ...50 8mm 30 Angular Field of View 20mm 2 5 20mm 1 6 10mm 1 3 8mm 0 7 Linear Field of View ft 1000yards 20mm 131 44 20mm 84 28 m 1000meters 10mm 67 22 8mm 37 13 Near Focus w 20mm Eyepiece 19 5 8m 15 4 5m Mount Altazimuth Photo Tripod Altazimuth Photo Tripod Altitude Locking Knob Yes Yes Azimuth Locking Knob No No CD ROM The SkyX Yes Yes Highest Useful Magnification 168x 120x Limiting Stellar Magnitud...

Page 18: ...CA 90503 U S A Tel 310 328 9560 Fax 310 212 5835 Website www celestron com Copyright 2010 Celestron All rights reserved Products or instructions may change without notice or obligation Item 21035 INST Printed in China 10 00 01 10 Rev 3 060909 ...

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