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Selected as "Astronomy Picture of the Day" for September 8, 2003
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[SII] = Red, Ha = Green, [OIII] = Blue
Twisters In hourglass region (image rotated 45degrees, magnified ~4x)
Twisters from Hubble
To read about the Twisters, click here
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re-processed to better match Hubble Colors
[SII] = Red, Ha = Green, [OIII] = Blue
---Image Exposure Details---
Halpha images taken August 19, 2003 at Fremont Peak State Park near San Juan Bautista, California
[OIII] and [SII] images taken August 22, 2003 at Plettstone, a private residence in the Sierra Gold Country in California (near Yosemite National Park)
Celestron C14 imaging scope @ f/11 (F=3910mm)
Finger Lakes Instrumentation IMG1024S imaging camera @-30C and @-27C
RCOS Dichroic Beam Splitter for AO7/IMG compatibility
SBIG ST7E Guide camera controlling
SBIG AO7 Adaptive Optics System
Astro-Physics AP1200GTO mount
Finger Lakes Instrumentation CFW1 Color Filter wheel
Custom Scientific Narrowband Emission Line Filters
[Sulfur II] 672.4nm 3nm FWHM
Hydrogen alpha 656.3nm 3nm FWHM
[Oxygen III] 500.7nm 3nm FWHM
Three exposures of ten minutes through each filter. Total exposure time 1.5 hours
Maxim DL 3.20 used for image acquisition, calibration, DDP, color combination
CCDSOFT 5.00.071 used for guiding/AO7 control
SIGMA Prebeta 11 used for darks, flats and image stacking