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Object Information
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Name: |
M101 (NGC5457) The Pinwheel Galaxy |
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Type: |
Spiral Galaxy |
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Description: |
M101 is thought to be twice the size of our own
galaxy, it has huge and extremely bright HII regions, these regions are the
nurseries of new stars. |
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Magnitude: |
7.5 |
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Size: |
28.8 x 26.9 arcminutes |
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References: |
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| Location
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Hemisphere: |
Northern |
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Location: |
Latitude 44.841N by Longitude -122.869W |
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Elevation: |
90 Meters |
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Date: |
February 21, 2009 |
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Time Zone: |
-8 (Pacific Standard Time) |
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Time: |
12:54am to 1:38am |
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Light Pollution: |
Class 4.5 on the Bortle scale (Rural/Suburban transition) |
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Equipment
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Imager: |
Nikon D90 |
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OTA: |
Nikkor 600mm F4 ED Telephoto Lens |
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Barlow: |
Nikkor TC-301 2x Teleconverter |
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Mount: |
Hypertuned Orion Atlas EQ-G |
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Guiding: |
Orion StarShoot Autoguider |
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Imaging
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Camera: |
Nikon D90 |
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NR: |
ON (Mode 2) |
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Quality: |
RAW |
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Size: |
4288 x 2848 |
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ISO: |
variable |
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Exposure: |
variable |
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White Balance: |
Direct sunlight, 0, 0 |
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Color
Space: |
sRGB |
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Exp Comp: |
0EV |
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Metering: |
Spot |
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Filter: |
Baader Semi-APO |
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Scale: |
0.38 arcseconds per pixel |
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FOV: |
54.99 x 34.80 arcminutes |
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Cropped FOV: |
41.31 x 34.65 arcminutes |
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Camera Control: |
Camera Control Pro 2.0 |
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Light
Fames: |
10 x (180s @ ISO800), 1 x (240s @ ISO800), 10 x (600s @ISO400) |
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Darks: |
auto darks via mode 2 |
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Flats: |
none |
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Total Exposure: |
2 hr 15mn 30s |
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Image Processing
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Stacking: |
DeepSkyStacker V 3.2.2 |
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Enhancement: |
PhotoShop CS3, Noiseware Professional, Astronomy Tools PS CS2 V1_5 |
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Notes
First picture of M101 during moonlight and within urban boundaries. I used
an aperture mask to reduce the lens aperture of a Nikkor 600mm f4 ED lens from 152mm down to 112mm, i.e.,
same thing as stopping down the aperture ring but without any diffraction
spikes.
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