|
Fine maps
bring the
fascination
of
hunting
out faint
secrets in
hidden sky
realms.
--Alan
MacRobert |
2.3. Star Atlases
ALL NAVIGATORS ,
no matter how experienced, rely on maps to guide them. As captain of your
telescope, you will need a good star atlas to find your way about the night sky.
It is one of the most important observing aids for the astronomer.
Many
introductory astronomy books contain starmaps for the beginner, some good, some
not so good. An excellent set of charts can be found in the Atlas of the
Night Sky, published in 1984 by Crescent Books. These charts, drawn by
master cartographer Wil Tirion, show stars as faint as 6th magnitude, which is
the faintest you can see with the naked eye from a good suburban site. Many
deep-sky objects are plotted, and variable stars brighter than 6th magnitude at
maximum are shown. Notable objects are listed beside each pair of charts. These
charts are exceptional because the whole night sky is shown on only 5 A3-sized
pages. They are excellent for use with binoculars, and their handy size make
them easy to transport and use. For the beginner, these charts are arguably the
best available, since they accurately summarize the night sky into clear,
understandable sections.
The more experienced telescopic observer will need charts that
show fainter stars and more deep-sky objects. The Uranometria 2000.0
atlas, published in 1987 by Willmann-Bell, is the Rolls-Royce of amateur star
atlases. A two- volume set, it contains 473 computer-generated charts, showing
330,000 stars down to magnitude 9.5. The complete Revised New General Catalogue
(RNGC) and an additional 10,300 deep-sky objects are shown. Each volume has a
two-page hemisphere starmap which indexes the charts in that volume, making it
easy to find the chart you need. The index maps are also very useful to help you
orient yourself when you start your observing session.
2.4. Miscellaneous Equipment
DEEPSKY OBSERVING IS
DONE in the dark. Well, almost. You will need some light to read
the star charts, make notes and find your mug of hot coffee. A normal torch,
useful during a power cut, is unusable at the telescope. Astronomers
traditionally use a dim red flashlight because red light has less effect on
night vision. Simply place sufficient layers of dark red cellophane (used for
gift wrapping) in front of the torch, thereby cutting down and filtering the
light. You can also paint the bulb with red nail polish for a more permanent
arrangement.
BECAUSE OF THE
NOTORIOUS NATURE of human memory, you will need some way of
recording your observations. At the telescope, a pencil and writing pad on a
clipboard works well, as does a Dictaphone or tape recorder. I find using a
small Dictaphone easier than writing descriptions by hand, partially because my
handwriting is illegible but mainly because it is more convenient and allows
greater freedom of expression.
For sketching, a dark pencil, eraser and
clipboard are useful, as well as sheets of paper with predrawn circles
representing the field of view. Whichever record keeping method you choose, you
should note the date and time of the observation, where the observation was made
and with which instrument, the magnification used, and the condition of the sky.
Record the sky conditions (seeing and transparency) and also include comments on
clouds, haze or the presence of moonlight.
Many observers design a standard
observing form, which can be filled in at the telescope. This ensures you don't
forget some important detail. After the observing session, your rough observing
notes should be edited and transferred to a standard record keeping system,
which will map your progress as a deep-sky observer.
REMEMBER TO DRESS
APPROPRIATELY for your observing session. Jeans and a T-shirt
might be fine for warm summer nights, but cold winter nights demand a wiser
choice. Jeans won't keep your legs warm enough - wear a pair of long-johns
underneath. Two tracksuit pants - instead of the jeans - also work well. A
sensible jacket, with several pockets, can be worn over a jersey and shirt to
keep the upper part of your body warm. Wear two pairs of woolly socks and make
sure your shoes or boots provide insulation, so that your feet don't leak heat
to the ground. Most important of all, protect your extremities. Your nose, ears
and fingers will loose heat more quickly. A balaclava and scarf will serve
admirably, and a pair of warm, non-bulky mittens will keep your fingers agile
and comfortable.
OBSERVERS OFTEN
OVERLOOK the fact that they will be spending a considerable
amount of time sitting at the eyepiece. Make sure your chair is comfortable and
supports you in the right places. Bear in mind that the eyepiece will not be at
a constant height throughout the night; some form of adjustable chair may be
needed. When observing with my binoculars, I use a plastic milk crate (either on
end or on its side) and various cushions for fine adjustment. Be careful not to
strain your back or neck when observing — you grow tired much sooner and
your overall performance is adversely affected.
DON'T FORGET TO PACK
IN some snacks. Something hot to drink after you have just found
that elusive galaxy adds to the reward. A sandwich, or some chocolate adds a
little extra boost during your vigil at the eyepiece. |
