answered about Astroplot charts.
daily astroplot chart updated on this website is valid worldwide
astroplot chart updated on this website is a universal reference
for the Northern and Southern Hemispheres. The RA plot of celestial
bodies across the Zodiac constellations presented on the daily Astroplot
chart is valid wherever you live on the Earth.
Astroplot chart has a circle calendar, is that what I refer to
plot the dates the Sun moves across the Zodiac constellations?
Instructions on how to
refer to the calendar is describe on the reference
12 charts round the central Astroplot calendar, how do I use it
as a reference to plot the sky for any 24 hour period throughout
You may have missed the
Astroplot chart reference page on this website. Go to astroplot
reference to see how to refer to an Astroplot chart and relate
it to the sky you observe.
is the longitude and latitude of the monthly star charts that
are illustrated on the Astroplot chart?
The Longitude and latitude
for the Astroplot chart was based on
the location of Sydney, Australia. Longitude 151 East, Latitude
34 South. This latitude was selected because it is determined to
be an average latitude that meets the major population areas in
the Southern Hemisphere Countries: Australia, New Zealand, South
Africa and South America.
much of the sky can I see compared to a sky chart?
Each sky chart represents
the whole sky, with the edge of the circle being the horizon.
live in Perth, where our time zone is 2 hours behind Sydney. Will
this 2 hour difference effect the start time and views using the
'Clock Process' on the Astroplot chart?
Time is coordinated with
the rotation of the Earth. When the Sun sets at 8 pm in Sydney,
two hours later in Perth, the Sun will set at around 8 pm. The same
stars that rose above the Sydney horizon at 10 PM will also rise
above the Perth horizon at 10 pm. The rise and set times of stars
are not exactly comparable from one time zone to the next. Variance
occurs because longitude for a time zone is wide, and latitude also
causes a difference. However, for a general guide of sky views across
the Southern Hemisphere, the Astroplot 'Clock Process' is relevant
to your place and time.
is the day of the month that reflects the sky at exactly 8 PM
for each monthly sky chart?
Each chart per month
reflects the sky at 8 PM EST (Eastern Standard Time) on the 15th
of the month. For daylight saving months, a reflection of the sky
at 9 PM is illustrated. Selecting the 15th as the base chart was
a means to give an average reflection of the sky over a month period.
The variance of the sky view from the 1st of the month, compared
to the middle 15th of the month, is minus 60 minutes. At the other
end of the range, on the 30th of the month, there is a variance
of plus 60 minutes.
Orion constellation on the chart is not the usual configuration,
As described on the Astroplot
chart, Orion is configured for Southern Hemisphere observers viewpoint,
which is upside down compared to the Northern Hemisphere viewpoint.
Check a range of astronomy books and you will find constellation
configurations vary. However, there are constellation boundaries
which constellations should be drawn within. Astroplot constellations
are drawn within the specified constellation boundaries.
you use Astroplot for dates in the past? Asked
by Belinda Jasper.
Yes, Astroplot is a reference
for past and present dates, being a perpetual sky calendar. For
example, let us compare two people who are born on the same day
of the year. Person one is born in 1970, while person two is born
in 2010. Both refer to the centre calendar to align a date with
the ecliptic to see where the Sun is in the Zodiac on their birthday.
When an astronomy plot program is referred to compare the 40 years
of time difference, there is a minuscule, indistinguishable and
Alright, to get particular,
taking precession into account, the Zodiac is measured to shift
one degree clockwise along the ecliptic every 74 years. Therefore,
someone born in 1930, eighty years ago, would be plotted a degree,
or a day, clockwise on the centre calendar ecliptic. Keep in mind
a finger pointer relevant to the Astroplot calendar is about 4 degrees
wide, so the difference is relatively insignificant.
is an Astroplot of the Northern Hemisphere going to be published?
An Astroplot of the Northern
Hemisphere is currently being designed. The schedule for publication
and distribution of the Northern Hemisphere Astroplot will be June
aren't the Astroplot sky charts the typical layout? Astronomy
sky charts usually have east and west around the other way?
Having a chart with east
and west plotted the opposite to a geographical map confuses and
disorientates the average person. Astroplot sky charts are referred
to as mirror projections. Such a projection allows people to read
the sky charts as they would a map Traditional sky charts have to
be physically orientated according to the direction faced by the
viewer to get their bearings. The examples below illustrate the
two sky chart types.
and West are not map orientation
Sky Chart - Mirror Projection
and West are map orientation