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OAOG Observing Challenge
By Denis Legault
A catalog of the best 600 deep sky objects that can be observed
from the Ottawa area. OAOG Challenge has been researched, designed and
observed in one year by local amateur astronomer Denis Legault. Scroll down
this page to find the downloadable links for all the files.
The purpose of the OAOG Challenge is to provide amateur astronomers with the
easiest deep sky objects to observe from the large NGC and IC catalogs.
The NGC and IC catalogs combined have over 10,000 objects. Which objects
should be attempted first? When are these objects visible? The OAOG
Challenge simplifies the task of choosing which objects to observe from
these lists. The first 5 levels of the OAOG Challenge have all been observed
using an 8 inches telescope. Future level 6 and level 7 will add an extra
400 objects to this list and bring the total to 1000.
The OAOG Challenge is divided into 5 difficulty levels. It can be used by
beginner observers and experienced observers.
Levels 1 and 2 are recommended as a starting point for beginners
A lot of these objects are visible using binoculars. A good small telescope
(3 to 5 inches) should be enough to see both of these levels. By the time
the level 3 objects are done, all of the Messier objects will have been
observed. Level 4 and 5 are for more experienced observers and require a
medium size (6 to 8 inches) telescope.
Most of the objects in the OAOG Challenge are from the Messier, NGC or IC
catalogs. Almost all objects listed have a visual magnitude brighter than
11. There are just a few exceptions. Level 1 contains 40 objects, Level 2
has 80, Level 3 has 140, Level 4 has 160 and Level 5 has 180 objects.
There is a lot of information listed with the objects. They are identified
by their NGC/IC number and their Messier number. The catalog lists the
constellation, the type of object, the right ascension and the declination
for each object. Also listed is the visual magnitude, the object size in arc
minutes, the number of stars in open clusters and the galaxy type. Three
columns of dates help the observer plan observing sessions by providing the
date range to observe the objects, the date range the objects pass the south
meridian (highest point in the sky) and the date range best to photograph
the objects. The common name of the object and the difficulty level number
complete the information provided for each object.
The catalog is presented in different sections
These sections are work sheets in the main Excel file. They have also been
saved as different files for quick downloads from the web. The different
files are: complete object list of all levels, level 1 object list, level 2
object list, level 3 object list, level 4 object list, level 5 object list,
list of open clusters, list of globular clusters, list of nebulae, list of
galaxies, list of Messier objects, complete object list in order by levels.
An observation guideline is provided which suggests which month the objects
should be observed. This is divided into 6 sets of 2 months each. The
section is called `Proposed Months to Observe Objects'. When a constellation
is listed under November-December for example, it does not imply that those
months are the only months it can be observed. For example, Orion is listed
under November-December. In fact Orion can be observed in the mornings of
August through the evenings of April. The constellations have been divided
between months to spread them throughout the year. The months from November
to February have been assigned a shorter list on purpose. During these
months the average amateur astronomer tends to observe less frequently due
to bad weather or due to extreme cold conditions.
A good atlas is recommended to accompany this catalogue. It will simplify
finding the objects in the sky.
Images of all objects listed in the challenge can be
found here in Denis Legault's
Deep Sky Catalogue
Click here for a list of definitions and explanations used in the
files above.
Adobe Acrobat (PDF) format files require Adobe reader for viewing.
If you have trouble downloading the files or you have any questions about
the OAOG Challenge catalogue, you can reach me at
denis.legault@oaog.ca
Have fun observing with OAOG Challenge!
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