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Sky Charts and Stargazing (for Beginner)

There are many ways to produce a sky chart for viewing astronomical objects in the night sky. Those in the book are usually presented in a series of 12 months. The Northern Hemisphere charts usually show the sky from a latitude of 45oN (usable for latitude 10 to 15 degrees
north or south of this) - suitable for viewing in the United States, Canada, Europe, and Japan. The Southern Hemisphere charts usually depict the sky from a latitude of 35oS. These are for use in the South Pacific, Australia, New Zealand, South America, and southern Africa. The sky charts in Figure 08-01j,k divide the sky of the Northern Hemisphere in January into two quadrants one facing North, the other

Figure 08-01j Sky Chart, North [view large image]

Figure 08-01k Sky Chart, South [view large image]

South. It has a legend to show the various objects in the sky and the apparent magnitude of the objects.

Figure 08-01l shows the Northern sky at 50o latitude at midnight for the beginning of the four seasons. An one piece sky chart plots the sky with the North Pole at its center (see Figure 08-01m). An oval opening in an overlapping disc represents the heavens as seen from a certain latitude, e.g., 45oN. The time and date of viewing can be selected by rotating the disc around the center. This particular view is set at 22:00 h, January 20. The transparent cursor scale (from -50o to 90o) is used to calculate the declination of celestial objects. The right ascension is marked at the outer-most circle. The East and West are switched in the chart. It will show the correct direction by rotating 180o when it is held over head to compare with the actual sky view.

Figure 08-01l Sky Chart [view large image]

Figure 08-01m Star Finder [view large image]

Sky charts computer software is perhaps the most versatile. It allows the user to specify any location and date/time as shown in Figure 08-01n, which displays a chart tailored to a "Sample" with latitude 42o and longitude 270o at 22:00 h on January 20, 2004. The detail of objects can be adjusted by the user. It can display the ecliptic as well as the Galactic equator. The coordinate grids can be numbered. Outline of the Milky Way can be plotted on the chart. The name of each object (if not already shown) can be obtained by

Figure 08-01n Sky Chart, Computer Generated
[view large image]

Figure 08-01o Sky Chart, Horizon Coordinate
[view large image]

clicking the pointer (such as NGC2539 in the sample chart). Figure 08-01o shows the same chart in horizon coordinate facing North. This free sky charts software is offered by Cartes du Ciel.

Stargazing (for Beginner)

    Here's some comments about the four signposts :

  1. Spring -

  2. Summer -
  3. Autumn -

  4. Winter -

    Figure 08-01z Winter Night Sky (Northern Hemisphere)

Milky Way Gazing

In Figure 08-01z51, the Milky Way is displayed on a Celestial Sphere (squashed to show 2 poles and 18 hr). Its movement can be visualized by considering 2 branches hanging from the top (like a cloth hanger); the whole thing rotates in 24 hours cycle. Then it becomes rather obvious to see 2 slant ribbons moving from East to West, and a round ribbon overhead in near circular motion (in December, see the moving Milky Way by clicking Figure 08-01z4) as the globe turns in clockwise direction.
The lower South-West part of the Milky Way can be traced out by linking some interesting astronomical objects from the Carb Nebula (mv = 8.4, not visible by naked-eyes) - Betelgeuse (a bright star in the Orion constellation with mv ~ +1) - Sirius (the brightest star with mv = -1.46) - Vela X (a pulsar with mv = +6.9 not visible by naked-eye) - Alpha Centauri (the closest star system to Earth with mv = +0.01). See

Figure 08-01z51 MW on Celestial Sphere

Winter Night Sky for tracing out part of the Northern Milky Way by some constellations. The Milky Way is visible by naked-eyes only in country side away from city light as its mv ~ +5 is near the visual limit.
BTW, the original "Sky Chart" in Figure 08-01z51 has something to do with the "Pyramids at Giza".
    The 4 illustrations in the followings are very important in understanding Milky Way gazing :

  1. Figure 08-01z5 is the view from a planisphere similar to the one in Figure 08-01t but it is set specially on mid-night, June 23 to show some common features of the Milky Way (dotted ribbon) :
    • The segment from Capella in the Auriga (Aur) constellation to Deneb in Cygnus is almost parallel to the latitude N45 (for a total of ~ 150o). Thus, it always turns in circular motion.
    • The Sgr and Sco constellations in the Southern Hemisphere are both located ~ S35. They appear on the Southern horizon at the observational limit for N50 observer.
    • The Milky Way in between the above 2 cases runs in an acute angle to the latitudes and drifts across more or less like a slant ribbon over the sky. This is the most frequent viewing pattern.

    Figure 08-01z5 Milky Way à la Planisphere

    • The appearance of the Milky May also depends on the observer's latitude. For example at N50, the segment of Milky Way near the pole to declination 50o would turn around in circle, while the rest would drift to the West.

  2. Figure 08-01z6,a is a sideview of the Solar system within the Milky Way by an external observer, e.g., from a spaceship far far away. It is the same placement (as shown in Figure 08-01z6,b and z7) with different perspective. The Solar system is just a tiny spark within a vast expanse of the Milky Way.

  3. Figure 08-01z6,b is a Celestial Sphere with the Earth at its center. It is squashed to show both the North and South pole (in full view) and the front face is spread to show an 18 hrs of the sky while back face is magnified to cover the rest 6 hrs. The sense of the Earth's rotation is clockwise so that astronomical objects rise from the East and set at the West.

  4. The constellation chart in Figure 08-01z7 is the spherical version of the flat universe in Figure 08-01s. It shows the placement of various objects in abbreviation (see full name in the other chart). The Milky Way is displayed in more detail and accuracy. The Earth at the center also spins in clockwise direction.

Figure 08-01z6 Milky Way

Figure 08-01z7 Sky Chart

Table 02 below describes observation of the Milky Way in specific date/time at latitude ~ N50. The effect for the inclination of 23.4 o between the celestial and ecliptic planes is taken care of by the difference in the duration of night time.

Date Night Time
Milky Way Segment Comments
March 21 6 pm - 6 am
12 hrs
  • At dusk,    Sirius (SE horizon, in CMa) -
    Cas (W Zenith) - Cyg (N horizon).

  • At dawn,    Aur (N horizon) - Cas (E Zenith) - Sco (SW horizon).

  • See illustration in September 21.
  • In between this initial and final configurations, the segment from Mon to Cas swings to the West while the part from Aur to Cas turns in near circle around the North pole carrying Sco at its tail end to the West.
  • See Figure 08-01z6,b to visulize.
  • See a video of Milky Way - March
  • June 21 8 pm - 4 am
    8 hrs
  • At dusk,     Aur and Cas (N horizon) - Oph (SE).

  • At dawn,     Aur and Cas (N Zenith) - Oph (SW).

  • See illustration in December 21.
  • In between this initial and final configurations, the segment from Aur to Cas turns in near circle around the Northern pole while carrying Oph to SW.
  • See a "Milky Way - Summer" video facing South.
  • September 21 6 pm - 6 am
    12 hrs
  • At dusk,     Sco (SW horizon) - Cas (E Zenith) - Aur (N horizon).

  • At dawn,     Cyg (N horizon) - Cas (W Zenith) - Sirius (SE horizon, in CMa).

  • [view large image]
    Milky Way Views of March 21 and September 21.
  • In between this initial and final configurations, the segment from Sco to Cas winds up from SW while the part from Cas to Aur turns in near circle around the North pole bringing Mon back to SE. See Figure 08-01z6,b to visulize.
  • Note that the dusk and dawn patterns are the reverse of those for March 21 (same for December/June, 21).
  • See Figure 08-01x for a view of the Milky Way perpendicular to the horizon.
  • December 21 4 pm - 8 am
    16 hrs
  • At dusk,     Oph (SW) - Cas and Aur (N Zenith).

  • At dawn,    Oph (SE) - Cas and Aur (N horizon).

  • [view large image]
    Milky Way Views of June 21 and December 21.
  • In between this initial and final configurations, the segment from Oph to Aur turns around the North back to SE, while Cas and Aur moves in an arc around the Northern pole. This is the rare occasion when the Milky Way is easily visible as an arc over the sky.
  • See a "Milky Way - Winter" video facing North and a grand finale in 4 directions.
  • BTW, the first painting featuring a prominent Milky Way is probably the "Flight into Egypt" of the holy family by Adam Elsheimer in 1609. It clearly depicts a Winter scene (~ Christmas time) as the Milky Way is in the form of an arc over the sky.
  • Table 02 Milky Way Gazing

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