Re: The unid with slooh

From: Kevin Fetter (
Date: Tue Nov 26 2013 - 14:34:55 UTC

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    What the person at slooh replied awhile ago, when I asked about the system.
    We take a series of exposures during a mission and each exposure's time 
    hack is when that image is written to the database.  So the simple 
    answer is that the time represents the end of the exposure.
    However, in a 5-minute mission, we start with a 30-second exposure 
    through the red filter.  That is sent out as the initial black and white 
    image that you see.  We then expose through green and blue filters. 
    Those three are merged and the resulting color image is sent out.  We 
    then expose through a clear filter (called a Luminance image) and merge 
    each subsequent luminance image with the RGB stack.  So on an average 
    mission, we take a minimum of 4 exposures (R, G, B, L), and you see 
    three:  Red, RGB, LRGB.  If the slew time for the dome from the previous 
    target was minimal, we will get an extra image in at the end on a 
    5-minute mission, so we then take R, G, B, L, L; and you see R, RGB, 
    So for each image you get, the time hack is:
    R - when the red image is saved.
    RGB - when the RGB image is saved (includes time for the G & B images, 
    and the processing time to merge them).
    LRGB - when the luminance image is saved.
    Other info on the scope I was using
    Widefield Instrument: 85mm f/5.6 Apochromatic 
    Field of View: 1.4 × 1.1 degrees
    Camera Resolution: 1,600 × 
    1,200 pixels (binned 1×1)
    Filter Set: Luminance, Red, Green, Blue, Hα 
    N 28° 17' 59"    W 16° 30' 
    30" Alt: 2,359m
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