Overview
The observing list engine is a very powerful web server application which
generates ASCII text observing lists and sends them to your web browser.
The engine generates SQL (Structured Query Language) queries against the
NGC/IC Public Access Database which results in a very fast response time.
Listed below is an explanation of each of the user choices available on
the Observing List Generator page.
The Constellation Field
This field is a drop-down containing the names of the 89 constellations
which make up the entire sky. The International Astronomical Union only
specified 88 constellations, but since the constellation Serpens actually
occupies two distinct portions of the sky, we have used the more current
names for each of these two pieces of the the constellation, namely
Serpens Cauda (the tail of the serpent) and Serpens Caput (the head of
the serpent). Just choose (hightlight) the constellation for which you
want an observing list generated. The constellation names are in
alphabetical order, which should make the desired one easy to find.
The Object Type Field
This field is a drop-down containing all of the known object types
contained within the NGC and IC. Besides the obvious ones of Galaxy,
Open Cluster, Globular Cluster, Bright Nebula, and Planetary Nebula,
there are additionally the ones of Single Star, Double Star, Triple
Star, Asterism, and Super Nova Remnant. This is because some of the
NGC and IC designations turned out to be one of these types of objects.
The last object type is Unknown/Unverified which denotes NGC and IC
objects which can't be found using the cataloged coordinates and
description. These are the 'Puzzle' objects of the NGC and IC.
Just choose (hightlight) the object type for which you want an
observing list generated, or choose 'All Types' to generate an
observing list with all types of objects.
The Magnitude Limits Field
This field is a drop-down containing a list of magnitude limit
cut-off's. This allows you to limit the observing list to objects
which are brighter than a certain magnitude which is a way of
tailoring the observing list to your particular aperture size
telescope. These magnitude limits are the photographic magnitudes
as found in the professional catalogs. In some cases the actual
visual magnitude of the object will be reasonably close to the
cataloged photographic magnitude, and in other cases there will be
a large disparity between the photographic magnitude and the
actual visual magnitude as observed at the eyepiece. This is
dependent upon the color index of the object as well as the actual
surface brightness of the object and other factors. In general,
specifying a limiting photographic magnitude for your observing
list is a reasonable first cut at a list of objects for which you
have a chance of seeing with your particular telescope. Just
choose (hightlight) the faintest magnitude for which you want an
observing list generated.
The Include/Exclude Magnitude Field
This field is a two-choice drop-down. It allows you to exclude
objects for which there is no cataloged magnitude. There are a
number of objects in the NGC and IC for which this is the case.
In general, these are either very faint objects or are the object
types which are of type Unknown/Unverified. In some cases you
may want to include objects with no cataloged magnitude just to
try observing them as 'challenge' objects. Just select (highlight)
either 'Include' or 'Exclude' depending upon what you want to
see in your observing list.
The Catalogs Field
This field is a three-choice drop-down. It allows you to generate
your observing list using both NGC and IC catalogs, just the NGC,
or just the Index Catalogs. Just choose (highlight) the catalog
of interest for which you want to generate an observing list.
The Other Designations Field
This field is a three-choice drop-down. It allows you to generate
an observing list without regard to whether the objects have a
William Herschel or John Herschel designation associated with the
object. It also allows you to only generate a list for which the
objects have a William Herschel designation, or a John Herschel
designation. If you choose 'Any or No Other Catalog', then
your observing list will contain the secondary catalog designation
for which the object is best known. If you choose either William
Herschel or John Herschel, then your observing list will contain
the respective 'H' or 'h' designation for each object listed, and
will exclude objects which have no William Herschel or John
Herschel designation depending upon your selection. Just choose
(highlight) your choice of other designation for which you want
to include in your observing list.
Observing List Format Choices
This section contains two mutually exclusive choices. You can
generate an observing list with one line per object, which includes
only very basic data about the object. This choice allows you to
generate the physically smallest list based upon your other choices,
or, you can generate an observing list which will also contain the
NGC/IC description for each object listed. This last choice uses a
second line to write the description of the object, and then writes
a blank line to help delimit the objects, thus making it somewhat
easier to read. You may want to experiment with these choices before
saving the final list you generate.
General Notes and Comments
To save your observing list, just go to the 'File' drop-down menu
on your web browser's menu bar. Select 'Save As...', which will
bring up a dialog window where you can select where you want to
save the observing list. In some cases, the default name chosen
for your observing list will be 'obslist.asp', which is the name
of the observing list engine located on the web server. Just
change the default name to one more meaningful, give it the
extension of '.txt', and click the 'Save' button. As an example,
if you generated an observing list for Orion, then 'Orion.txt'
might be an appropriate name for the saved observing list file.
In no case will you be able to actually save the observing list
engine (obslist.asp which is the default name chosen by your
web browser) as that can only be evoked from your web browser,
and not actually downloaded and saved.
You should also be aware that because of all of the various
choices allowed for tailoring your observing list, you can
specify combinations of choices which will not return any objects
in an observing list. For instance, William Herschel was only
associated with the NGC and not the IC's. Therefore if you
specify 'IC Only' for the catalog field, and 'H (William Herschel)'
in the 'Other Designations' field, you will end up with an
empty observing list.
If you have any additional questions, or suggestions, please
feel free to contact the Webmaster.
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