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Q: Locating a star and it's star chart ( Answered 5 out of 5 stars,   0 Comments )
Question  
Subject: Locating a star and it's star chart
Category: Science > Astronomy
Asked by: naoise-ga
List Price: $25.00
Posted: 16 Dec 2002 14:40 PST
Expires: 15 Jan 2003 14:40 PST
Question ID: 125610
Hi there,

I was recently considering 'buying a star' for a relative, but realized
soon after looking into it that you cannot actually buy a star, and
people selling this service are simply making a quick buck.

This doesn't depreciate the quality of the gesture though, and I was
still hoping to 'dedicate' a star to the memory of a relative's son.

My trouble is choosing a star, and being certain of 
a) it's location in the sky, (the declination etc.)
b) it's catalogue number (one that the majority of astronomers could
use to find it)
c) whether the star is visible from my northern hemisphere (southern
ontario, Canada).

I can find star charts to print here: http://charts.aavso.org

The perfect answer to this question would be:

"A good choice of star to dedicate would be found at this location
_____ in this constellation ____ and has a catalogue number of _____
and you can find charts for it at charts.aavso.org by searching by
name/catnumber for _____ "

A direct link to a star chart would be great. I’d like to be able to
circle the area the star would be visible in.

A great bonus would be some laymans terms instructions for locating
the area  of the sky the star is in. Something like "To find this
star, start at the big dipper, follow a line towards the north star"
etc.

I'm not looking for a star you can see brightly with the human eye,
but rather one that may lie beside such a star, which would make it
easier to find with some magnification.
Answer  
Subject: Re: Locating a star and it's star chart
Answered By: justaskscott-ga on 16 Dec 2002 22:41 PST
Rated:5 out of 5 stars
 
Hello naoise-ga,

I feel privileged, as anyone would, to have the opportunity to answer
this question.  I think that your idea is wonderful: to give the gift
of a star, not a star chosen for you by a corporation, but one for
which you have set the parameters, and one that your relative can
appreciate in the night sky of southern Ontario.  I make you this
promise: if you don't like the star I propose, I will gladly find
another one; and if you don't like my work in general, I will gladly
move aside to allow another Researcher to find a star.

Based on your question, I have looked for a star that meets the
following criteria: frequently visible from southern Ontario; bright
enough to see, at least with a little magnification, but not too
bright; and easy to find in relation to a bright star or
constellation.  (At first, I thought I should also search for a star
that has a legend associated with it; but then I realized that mainly
the brighter stars would give rise to legends.)  Also, since you have
some familiarity with the AAVSO charts, I have looked for a star that
is listed on those charts.  (AAVSO is dedicated to variable stars, or
stars with changing brightness, so I looked specifically for that kind
of star.)

I figured that the guide star for my search, literally and
figuratively, should be Polaris, the North Star.  If a star is near
Polaris, it will be visible anywhere in Canada throughout the year. 
You can see this for yourself by trying this very helpful sky chart:

"Sky Chart"
Sky and Telescope
http://skyandtelescope.com/observing/skychart/

One of the most recognizable constellations in the northern sky, and
certainly one of the most recognizable near Polaris, is Cassiopeia. 
You are probably familiar with it already, but if not, the five
brightest stars form a large letter "W", or an "M" when turned upside
down.  (I grew up in southern New York, which is not too far south of
southern Canada, and the constellations I knew best were Cassiopeia
and the Big Dipper -- which are on opposite sides of Polaris, the
handle tip for the Little Dipper.)

I looked at the AAVSO charts for the Big Dipper (Ursa Major), but the
charts showed only a small portion of the constellation, so that one
cannot easily tell what part of the constellation a star is in. 
Cassiopeia, which is just as recognizable, is also smaller, so the
charts are easier to decipher.

In searching for stars near Polaris, I came across Rho Cassiopeiae
(Rho Cas), which is listed in a chart of variable stars visible in
southern Ontario.  The Harvard Designation for the star is 2349+56,
which means that its right ascension was 23 hours, 49 minutes in the
year 1900, and its declination was 56 degrees north in 1900.  (There
are several catalogs for stars; it seems that the Harvard Designation,
or simply "designation", is a common way of categorizing variable
stars.)

"Catch a 'Falling' Star in Your Binoculars!" (December 1996)
Event Horizon
Hamilton Amateur Astronomers
http://amateurastronomy.org/EH/Dec96.PDF

"The Harvard Designation of Variable Stars", by Margaret W. Mayall
The American Association of Variable Star Observers (AAVSO)
http://www.aavso.org/vstar/harvarddesig.stm

The chart for Rho Cas shows its location quite nicely.  First, tilt
your head so that the "W" is straight like a "W" typed on a page. 
(You can just tilt the constellation in your mind, if you prefer, so
that the W is straight.)  If you look to the right of the right tip of
the "W" (labeled with the Greek letter beta), there are two labeled
stars, one above the other.  The lower star is Rho Cas, labeled with
the Greek letter rho (which looks like the English letter "P"). 
Another way to find the star would be to draw a line from the left tip
to the right tip of the W, and then continue the line a little until
it bisects two stars.  The star just below that line is Rho Cas.

"Rho Cas (Cassiopeiae)" [A-GIF]
AAVSO
http://www.aavso.org/charts/CAS/RHO_CAS/RHOCAS-A.GIF

Here is another chart that labels Rho Cas:

"Cassiopeia"
Portraits of Stars and their Constellations [Jim Kaler, Professor of
Astronomy, University of Illinois]
http://www.astro.uiuc.edu/~kaler/sow/cas-t.html

The star is not as bright as the five main stars of Cassiopeia, but it
is actually very impressive.  Someday it will become a spectacular
supernova.

"Rho Cas"
Portraits of Stars and their Constellations [Jim Kaler, Professor of
Astronomy, University of Illinois]
http://www.astro.uiuc.edu/~kaler/sow/rhocas.html

So my answer, in the form that you outlined in the question, is: A
good choice of star to dedicate would be found to the right of the
right tip of Cassiopeia, and has a Harvard Designation of 2349+56, and
you can find charts for it at http://charts.aavso.org by searching by
designation for 2349+56 or by name for Rho Cas.

I hope that this star will make a nice present for your relative.  As
I said, if you don't like it, I will look for another one.

- justaskscott-ga


In addition to browsing the AAVSO site, I searched for the following
terms on Google, sometimes in combination:

"variable stars"
"southern ontario"
"rho cassiopeiae"
"rho cas"
rho cassiopeia
"2349+56"
"star catalogs"
"star catalogues"
naoise-ga rated this answer:5 out of 5 stars
This is a great answer, and covers what I was looking for.

Thanks very much.

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