Monthly Archives: September 2018

    Waxing Crescent

    Waxing Crescent

    Two-day-old waxing crescent

    • Telescope: Stellarvue SVA130T-IS
    • Mount: Losmandy G-11 with Gemini 2 controller
    • Autoguiding: No
    • Optical Configuration: 2x Barlow (f/14)
    • Camera: Canon 60Da
    • Light Frames: Single frame, 1/125-sec. exposure
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time: 1/125 sec.
    • ISO: 1250
    • Processing: Photoshop CC
    • Imaging Location: Sierra Nevada Mountains (Altitude: 8,600 ft)

    This two-day-old waxing crescent of the Moon was shot while waiting for darkness to fall in the High Sierra.

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    The Heart Nebula (IC 1805)

    The Heart Nebula (IC 1805)

    This H-II emission nebula traces a red heart in the constellation Cassiopeia.

    • Telescope: Stellarvue SVA130T-IS
    • Mount: Losmandy G-11 with Gemini 2 controller
    • Autoguiding: Yes
    • Optical Configuration: 0.72x field flattener & reducer (f/5)
    • Camera: Canon 60Da
    • Light Frames: 25, 6-min. exposures
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time: 150 min. (25 x 6 min.)
    • ISO: 800
    • Processing: Photoshop CC
    • Imaging Location: Sierra Nevada Mountains (Altitude: 8,600 ft)

    About 7,500 light-years away in the constellation Cassiopeia, the feeble red light from a very dim emission nebula traces the shape of a heart in the sky. With an apparent magnitude of only 18.3, the aptly named Heart Nebula requires long exposures to tease out the details of its shape.

    Ultraviolet light from the open cluster of stars (Melotte 15) near the nebula’s center stimulates the  re-emission of red light from ionized hydrogen gas (H II) in the interstellar medium. Hints of blue light from doubly ionized interstellar oxygen gas (O III) also can be seen throughout the nebula.

    Because the nebula’s size exceeds the widest field of view of the telescope-sensor configuration (1.95° x 1.30°), some parts of the object extend off frame in the image above.

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    The Triangulum Galaxy (M33)

    Triangulum Galaxy (M33)

    The Triangulum Galaxy (M33) is the third largest member of our Local Group.

    • Telescope: Stellarvue SVA130T-IS
    • Mount: Losmandy G-11 with Gemini 2 controller
    • Autoguiding: Yes
    • Optical Configuration: 0.72x field flattener & reducer (f/5)
    • Camera: Canon 60Da
    • Light Frames: 24, 5-min. exposures
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time: 120 min. (24 x 5 min.)
    • ISO: 800
    • Processing: Photoshop CC
    • Imaging Location: Sierra Nevada Mountains (Altitude: 8,600 ft)

    On a very dark and clear autumn night, a sharp eye can spot the Triangulum Galaxy (M33) high in the sky in the constellation Triangulum. At a distance of 3 million light-years, it is one of the farthest objects that can be seen with the naked eye.

    The Triangulum Galaxy lives right next door to the Andromeda Galaxy (M31) in the constellation Andromeda, which is the largest member of our Local Group of galaxies that includes Andromeda (#1), our galaxy the Milky Way (#2), and Triangulum (#3). Altogether, our Local Group contains more than 54 galaxies.

    The Triangulum Galaxy spans about 60,000 light-years and may contain 40 billion stars, which is about one tenth the number of stars in our galaxy.

    [For Tom, whose artful words live on.]

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    Dark Matter, NGC 672 & IC 1727

    NGC 672 & IC 1727

    Could dark matter be influencing the interaction of galaxies NGC 672 & IC 1727?

    • Telescope: Stellarvue SVA130T-IS
    • Mount: Losmandy G-11 with Gemini 2 controller
    • Autoguiding: Yes
    • Optical Configuration: 0.72x field flattener & reducer (f/5)
    • Camera: Canon 60Da
    • Light Frames: 20, 6-min. exposures
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time: 120 min. (20 x 6 min.)
    • ISO: 800
    • Processing: Photoshop CC
    • Imaging Location: Sierra Nevada Mountains (Altitude: 8,600 ft)

    Around 20 million light-years away in the constellation Triangulum, dark matter could be dominating the behavior of several galaxies. In a 2008 paper, astronomers Zitrin and Brosch observed that NGC 672, IC 1727, and 12 smaller galaxies all seem to be moving together with a long filament of dark matter stretching across 6° of sky, or 1.7 million light-years. NGC 672 and IC 1727 are the two largest galaxies in the above image (left and right, respectively). This filament of dark matter, they believe, also stimulates the nearly simultaneous creation of new stars within the galaxies that are caught in its gravitational grip.

    Through the telescope, NGC 672 and IC 1727 can be seen huddled together less than 90,000 light-years apart. At 26 million light-years away, they form a relatively close galactic pair to us. But far more distant galaxies also can be spotted in the image above. Arrows identify two of these remote galaxies and their distances, estimated from their cataloged redshifts.

    [For Michael, whose intellect and compassion brightened our lives.]

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