Category Archives: Astroimaging

    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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    Veil Nebula Revisited

    Eastern Veil Nebula

    Eastern Veil Nebula (NGC 6992) reprocessed with a new bag of tricks

    • 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, 5-min. exposures
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time: 125 min. (25 x 5 min.)
    • ISO: 1250
    • Processing: Photoshop CC
    • Imaging Location: Prairie City, Ore.

    As mentioned in a previous post, the Veil Nebula poses something of a challenge for astrophotographers. Located in a dense star field in the constellation Cygnus, this relatively dim emission nebula must compete for attention among thousands of stars. But Papa’s got a new bag of tricks, so it’s not much of a competition anymore.

    The above image was processed with the same imaging data used for the original images posted in September 2017 (https://tvhiggins.com/astroimaging/the-east-veil-nebula-ngc-6992/), but the results are very different.

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    The Pinwheel Galaxy Neighborhood

    Pinwheel Galaxy & Neighbors

    Full-frame image of the Pinwheel Galaxy includes some neighboring galaxies.

    • 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: 41, 300-s subframes stacked (205 min.)
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time(s): 3.42 h, 205 min. (41 x 5 min.)
    • ISO: 800
    • Processing: Photoshop CC
    • Imaging Location: Sierra Nevada Mountains (Altitude: 8,600 ft)

    This full-frame image depicts the Pinwheel Galaxy (M101) and some nearby galaxies:

    • NGC 5473 (right); Distance: 109 Mly
    • NGC 5485 (upper right); Distance: 91.1 Mly
    • NGC 5477 (above and to the right of M101): Distance: 20.9 Mly
    • NGC 5474 (top left); Distance: 21.2 Mly

    The gravitational influence of the Pinwheel Galaxy is most evident in NGC 5474, which has an off-center nucleus possibly caused by a previous close encounter with M101.

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    The Pinwheel Galaxy (M101)

    The Pinwheel Galaxy (M101)

    The Pinwheel Galaxy (M101) in Ursa Major

    • 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: 41, 300-s subframes stacked (205 min.)
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time(s): 3.42 h, 205 min. (41 x 5 min.)
    • ISO: 800
    • Processing: Photoshop CC
    • Imaging Location: Sierra Nevada Mountains (Altitude: 8,600 ft)

    About 21 million light-years away in the constellation Ursa Major (The Big Dipper), the Pinwheel Galaxy (M101) offers one of the finest examples of a spiral galaxy. Oriented face-on, its spiral structure displays colorful red, white, and blue regions rich in new star formation. The red regions denote vast areas of molecular hydrogen gas, where new stars are born, and the bright blue areas shine from thousands of hot young stars. Astronomers estimate that the Pinwheel Galaxy (M101) is 170,000 light-years in diameter and contains a trillion stars.

    The Pinwheel Galaxy has hosted an unusual number of supernovas, with a total of four being observed since 1909. Encounters with five prominent companion galaxies have also led to some obvious distortions of the spiral arms.

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    The Dumbbell Nebula (M27)

    Dumbbell Nebula (M27)

    The Dumbbell Nebula (M27)

    • 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: 15, 300-s subframes stacked (75 min.)
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time(s): 75 min. (15 x 5 min.)
    • ISO: 800
    • Processing: Photoshop CC
    • Imaging Location: Sierra Nevada Mountains (Altitude: 8,600 ft)

    When a star reaches the end of its life, it sometimes leaves behind a colorful display of its demise called a “planetary nebula.” The Dumbbell Nebula (M27) is the largest such display in our sky, and certainly one of the most colorful. This planetary nebula is about 1 light-year across and about 1,360 light-years away, giving it an angular width of about 5 to 8 arcminutes in the nighttime sky, depending on which way you measure it. It may be as much as 14,600 years old and is “slowly” expanding at an estimated speed of 31 km/s, or about twice the speed of Voyager II as it leaves our solar system. The star responsible for this colorful ball of expanding gas can be seen at the exact center of the nebula in the image above.

    The Dumbbell Nebula is located in the constellation Vulpecula (“little fox” in Latin) surrounded by a dense field of thousands of stars, as shown in this full-frame image below:

    Dumbbell Nebula, Full-Frame

    In this full-frame image, the Dumbbell Nebula (M27) resembles a soap bubble floating among thousands of stars. (Field of view < 2 degrees wide.)

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