Searching
for Arakelian
How to add
Obscure Objects to your SkyTools Observing List Astronomical
designations are one of the more fun and interesting aspects of
our hobby. But the large number of obscure or arcane
catalog identifiers can lead to frustration when creating your
own SkyTools observing list. This guide will explain how
to go about dealing with this problem. But
first a little perspective. Why doesn't SkyTools simply
have all the catalog designations in it so I can type in
Arakelian 320 and get my galaxy directly? The answer has
to do with how professional astronomers work and how
designations come about in the first place. The
Swartz Galaxies Once
upon a time there was a graduate student at the University of
Illinois names Swartz. His dissertation had to do with
modeling the rotational velocities of galaxies. He spent
many late nights eating pizza and Top Ramen at his desk creating
a computer model. In order to test his computer model his
advisor got him time on a big telescope in Texas. But
first he needed targets: galaxies that are very close to being
edge on. Swartz poured through the catalogs and online
databases looking for appropriate galaxies and compiled a list
as he went. All of these galaxies were already known and
had designations such as NGC, UGC and MCG. Eventually he
finished his dissertation and published his work in the
Astrophysical Journal. Years
later an amateur astronomer named Jones got to talking to a
woman at a star party. She had gone to school with
Swartz. They were observing a nice edge-on galaxy in
Jones' Dob. One thing lead to another and she mentioned
that Swartz had compiled a list of edge-on galaxies. When
Jones got home he looked up Swartz's paper and ended up writing
an article for Sky & Telescope titled, "Observing
the Swartz Galaxies." His table in the article
naturally listed these galaxies as Swartz 1 through Swartz 24
and he gave positions and other data for each. Meanwhile
Swartz's original table published in the ApJ ended up in the
hands of a guy who works for the NASA/IPAC Extragalactic
Database project (otherwise known as NED). He
diligently went about adding the Swartz galaxies by number to
NED. But he ran into a problem. Another astronomer
named Swartz had already created a "catalog" of
objects and the Swartz designation was already in use. So
he shortened Swartz to Swz for this new catalog, listing Swz 1
through Swz 24 in the database. Along
comes a guy named Andy who is really excited about creating an
observing list for his clubs nationally recognized star
party. He comes across the article about Swartz galaxies
in Sky & Telescope and decided to add Swartz 13 to his list
which is published prior to the event. Finally
we have Paul. Paul recently bought SkyTools and he's
excited about using it at the upcoming star party. He sets
about creating a SkyTools observing list with the objects that
Andy selected. But when he comes across Swartz 13,
SkyTools can't find it. So he asks a friend what to do and
his friend suggests using NED, which can be accessed
online. He types Swartz 13 into NED and gets a galaxy that
isn't even visible from the latitude of the star party. So
where the heck is the real Swartz 13 and how does he get
it into SkyTools? Variations
of the above fictional scenario play out continually, leading to
large numbers of obscure catalog identifiers that normally
wouldn't ever be used in practice, but for one reason or another
are included in a list of objects to observe. Often it's
simply that the author finds the obscure designation (like
Swartz 13 or Arakelian 320) to be more interesting. In his
mind he's published everything the observer needs to find
it. But with the increasing use of software planning tools
the author has in fact left the reader to make an involved
search for the object by not including the more common
identifier. How to add
Obscure Objects to your SkyTools Observing List There
are three reasons why SkyTools might not recognize an object
designation:
- The designation isn't
formatted the way SkyTools expects
- The catalog is so obscure
that cross references are not included for it
- The object is so obscure that
it is missing from the SkyTools database entirely
To the first issue: from my
fictional example above one can see that there is no standard
for catalog identifiers. It could be Swartz or Arakelian
or it could be Swz or Ark, or even something else. We try
to be as accommodating as possible, so that both will be
recognized, but it is always an evolving and ongoing
process. To see the format expected for designations in
SkyTools open the Object Requestor, select the type of
object you are looking for and browse the designations
available. A list will appear for each type on the
right. If you can format the designation the way it
appears you will have a high chance of success via the Quick
Search.
Sometimes an object with a
well-known designation recognized by SkyTools is referred to
only by an obscure designation that is not. There are two
online tools available that can help you look up the object via
the obscure designation.
SIMBAD
is an extensive database of all types of astronomical
objects. It has most of the obscure designations but there
are so many that they are often given very obscure formats
such as, ZW VII 421. So it can take some effort to use
this tool to find your object.
NED
is an extragalactic database best used for galaxies and
quasars. It is limited to these types of objects but is
more complete and more definitive than SIMBAD.
If you can find your object
using one of the above tools enter one of the many cross
identifications into SkyTools and go from there.
If you cannot find a cross
reference to a catalog identifier recognized by SkyTools then
the next approach is to use the coordinates provided. Open
the Interactive Atlas. Click on the target
hypertext. Select Enter J2000 Position under the Reference
Database pull down menu. Type the coordinates into the
Object Identifier box. The expected format is
"00:00:00 +00:00:00" with the R.A. first in hours,
minutes, seconds, followed by the Declination in degrees,
minutes, seconds. Press Enter. Click Ok.
Your object should now appear
near the center of the chart. Double-click on it to see
the Object Info. In the case of Arakelian 320 it turns out to be
the galaxy UGC 6732. Select Add Object to
Observing List from the Action Menu.
If no object appears at the
coordinates, click the Magnitude Limits button on the
button bar. For the type of object you are searching for
move the slider all the way to the right. Check the chart
again. Has it appeared? If not, then the object
isn't in the SkyTools database. Don't forget to return the
magnitude limit to the default.
Finally, you can add objects to
SkyTools via the Supplemental Database Editor (or SuppDB).
This is a stand alone program that comes with SkyTools and can
be launched from the Windows Start Menu. Close SkyTools
first. Once the Supplemental Database Editor is
started select the tab for the type of object you wish to
add. Click the New button. Enter
the object data on the right. Click Save.
Close the editor.
When you restart SkyTools type
the designation for the object you created (such as "Swartz
13") into the quick search and press enter. It should
be found. Now add the object you your list in the usual
manner.
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