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Collection of Emission, Planetary, and Diffuse Nebulae, Galaxies, and Comets About Filters: Hydrogen alpha (Ha), doubly ionized oxygen (OIII) and ionized sulfur (SII) filters are used to record gas emission line nebulae from particular regions of our galaxy. Visible light from a narrow bandwidth (corresponding to a particular gas) is color mapped onto red (sulfur), green (hydrogen) and blue (oxygen) channels using the standard Hubble palette. In some cases, I used only the Ha filter (no color mapping). Narrowband filters effectively block the urban glow (street lamps, shopping malls, homes) and light reflected from the moon, significantly increasing S/N. Other images were obtained using conventional LRGB filters, with an Ha filter often used to enhance the hydrogen emission. About the Images: Unlike planets, comets, and other solar system objects, deep sky objects are quite distant and faint. The closest nebulae are approximately 300-500 light years away, while the most distant object shown in this collection is 25 million light years away. Such distances require very extended camera exposure times - on the order of hours. Total exposure times for some objects are in excess of 7 hrs with 3-4 hrs being typical. About the Equipment: These images were taken using a CCD camera from SBIG. The camera has two photosensitive chips (CCDs): a larger one to image the target object and a smaller one to lock on a nearby guide star for fine telescope position control to compensate for earth's rotation (over several hours). The camera body and filter wheel are attached a telescope and mounted on a sturdy German equatorial mount. All aspects of the imaging process (aiming, focus, guiding, filter selection, exposure time) are automatically controlled by a notebook computer.
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Spiral Galaxy M51 04.15.12 |
Spiral Galaxy M101 03.26.12 |
C/2009 P1 Garradd 03.20.12 |
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NGC 2264: Cone Nebula 01.25.12 |
IC 2177: Seagull Nebula 01.17.12 |
IC 434: Horsehead Nebula 01.12.12 |
Abell 21: Medusa Nebula 12.23.11 |
M42: Orion Nebula 12.20.11 |
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NGC 2174: Monkey Head Nebula 12.3.11 |
Sh2-216 - Planetary Nebula 11.24.11 |
Sh2-240 - Supernova Remnant 11.21.11 |
IC 1805 - Heart Nebula 11.2.11 |
NGC 281 - Pacman Nebula 11.1.11 |
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M16 - Eagle Nebula 7.18.11
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M27 - Dumbbell Nebula 7.23.11
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IC 5070: Pelican Nebula 8.1.11
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M76: Planetary Nebula 10.11.11
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NGC1499 - California Nebula 11.15.10
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Sh2-261 - Lower's Nebula 12.23.09
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NGC 2244- Rosette Nebula 2.17.10
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IC410 - The Tadpoles 11.24.09
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IC 2162 12.16.09
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NGC 7000- North American Nebula 8.24.09
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NGC2264 -Cone Nebula 2.18.09
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IC 443 -Supernova Remnant 3.15.09
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NGC6960 - Veil Nebula 7.11.09
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M42- Orion Nebula 1.14.09
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NGC7635 - Bubble Nebula 8.21.10
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