Celestron 91525 Telescope User Manual


 
Celestial Observing 47
Star hopping may take some getting used to since you can see more stars
through the finder than you can see with the naked eye. And, some objects
are not visible in the finder. One such object is M57, the famed Ring Nebula.
Heres 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) Lyrae.
4. Point the finder half way between these two stars.
5. Move about 1/2° toward Beta (β) Lyrae, but remaining on a line that
connects the two stars.
6. Look through the telescope and the Ring Nebula should be in the tele-
scope. Its angular size is quite small and, therefore, not visible in the
finder.
Because the Ring Nebula is rather faint, you may need to use averted vision to
see it. Averted vision is the act of looking slightly away from the object you are
observing. So, if you are observing the Ring Nebula, center it in the field of
view and then look off toward the side. In this manner, light from the object is
falling on the black and white sensitive rods as opposed to the color sensitive
cones. 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 any of the star
atlases and star hop to the object of your choice using naked eye stars.
Figure 6-4
Although the Ring Nebula lies
between two naked eye stars, it
may take a little time to locate
since it is not visible in the
finder. Note that the scale for
this star chart is different from
the one on the previous page
which shows several constella-
tions including Pegasus,
Triangulum, and Andromeda.