Observing-Challenge-Feb-2009
Ottawa Centre Monthly Observing Challenges
Beginning in 2007, Ottawa Centre introduced a new item to its monthly meetings: an observing challenge object. Each month the centre will post a description of an interesting object. Members are invited to observe, sketch, photograph, or otherwise learn about this object. At the subsequent monthly meeting, an agenda item will provide an opportunity to share your thoughts, photos, sketches, or comments.
February 2009
Lunar: Observing with Negatives
By Brian McCullough
February's Lunar challenge is for a technique, not a specific target. Brian discussed how taking photographic negatives of lunar images often reveals detail not visible in the normal positive shots, because our eye is optimized to detect certain types of contrast. The challenge is for lunar images to use their image-editing software to produce photo-negative versions of some of their images, and to bring examples of images where the use of positive and negative images reveals interesting different details.
| Most image-editing software, such as Photoshop, has the ability to invert an image to a negative. For example, this shows where the Invert command is located in Adobe Photoshop CS3. | 
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The following examples are some of Brian's own images.
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Deep Sky: M44 "Beehive"
by Attilla Danko
February's challenge is to observe M44, the Beehive Cluster. Observers with appropriate equipment (large scopes or imaging capability) are challenged to observe the galaxy cluster behind M44.
| Star by locating the constellation Cancer, to the left of Orion in the mid-evening Winter sky. |
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| The M44 cluster is located near the centre of the constellation. |
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| Here is a closer view of Cancer. The stars are rather dim, but can be found in a good clear sky in all but the worst light-pollution. |
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| Point your binoculars or telescope just above the centre star, just to the right of the line to the next star above centre. |
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| In clear dark skies, the cluster will be just visible as a fuzzy patch. In binoculars, it will stand out clearly. |
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| This image of the cluster from the Sloan Digital Sky Survey shows that there are a number of background galaxies. |
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Attilla provided the following chart of the galaxies behind this cluster. Observers with large scopes, or observers with imaging equipment, are challenged to locate as many of these galaxies as possible. From brightest to dimmest they are:
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