Category Archives: Astroimaging

    2017 Solar Eclipse Coronal Study I

    Coronal Study, 2017 Solar Eclipse

    High-contrast study highlights the sun's coronal structure during the 2017 total eclipse.

    • Telescope: Stellarvue SVA130T-IS
    • Mount: Losmandy G-11 with Gemini 2 controller
    • Autoguiding: No
    • Optical Configuration: 0.72x field flattener & reducer (f/5); no solar filter during totality
    • Camera: Canon 60Da
    • Light Frame(s): 13 full-stop, bracketed exposures from 1/2000 to 2 sec
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time(s): 1/2000 to 2 sec in full-stop increments
    • ISO: 100
    • Processing: Photoshop CC using the Pellett method
    • Imaging Location: Prairie City, Ore.

    This image uses the Pellett method to create a high-contrast study of the sun’s coronal structure during the 2017 solar eclipse. Note how the plasma streamers of the corona trace the magnetic field lines of the sun, like iron filings around a magnet.

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    2017 Solar Eclipse: The Moon and the Solar Corona

    Solar Corona & Moon

    Eclipsing Moon reveals the solar corona during The Great American Eclipse, 2017

    • Telescope: Stellarvue SVA130T-IS
    • Mount: Losmandy G-11 with Gemini 2 controller
    • Autoguiding: No
    • Optical Configuration: 0.72x field flattener & reducer (f/5); no solar filter during totality
    • Camera: Canon 60Da
    • Light Frame(s): Two-image composite of 1/30-sec and 1-sec exposures
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time: 1/30 sec + 1 sec
    • ISO: 100
    • Processing: Photoshop CC
    • Imaging Location: Prairie City, Ore.

    This composite image reveals many lunar features and the solar corona during The Great American Eclipse of 2017. Super-heated plasma escaping from the sun creates the solar corona and becomes the solar wind that blows through our solar system at a million miles per hour. The charged particles that make up the coronal plasma follow the magnetic field lines of the sun and form streamers in the corona, like iron filings around a magnet. In this image, north is up, south is down, east is left, and west is right.

    Sunlight reflecting from our Earth during the eclipse illuminates the Moon and bounces back to Earth as “earthshine.” Because of this earthshine, lunar features such as the “seas” and several large craters (Tycho, Copernicus, etc.) can be imaged during totality. The blue color of the Moon comes from our blue sky.

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    2017 Solar Eclipse: The Prominences

    Solar Prominences of Eclipse 2017

    Solar Prominences of The Great American Eclipse, 2017

    • Telescope: Stellarvue SVA130T-IS
    • Mount: Losmandy G-11 with Gemini 2 controller
    • Autoguiding: No
    • Optical Configuration: 0.72x field flattener & reducer (f/5); no solar filter during totality
    • Camera: Canon 60Da
    • Light Frame(s): Single, 1/500-sec exposure
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time: 1/500 sec
    • ISO: 100
    • Processing: Photoshop CC
    • Imaging Location: Prairie City, Ore.

    During the totality phase of a total solar eclipse, prominences sometimes can be seen along the limb of the sun. The image above shows two such prominences and several smaller ones that appeared during the 2017 solar eclipse (The Great American Eclipse).

    Prominences consist of a hot, dense plasma that usually follows the magnetic field lines of the sun, arcing thousands of miles above the surface (photosphere).

    [Many thanks to the Emmels of Prairie City, Ore., who made their ranch available to grateful eclipse viewers like me. Their hospitality made the experience even more enjoyable for all of us.]

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    The Andromeda Galaxy

    The Andromeda Galaxy

    The Andromeda Galaxy (M31)

    • Telescope: Stellarvue SVA130T-IS
    • Mount: Losmandy G-11 with Gemini 2 controller
    • Autoguiding: Yes (sub-arcsecond rms accuracy)
    • Optical Configuration: 0.72x field flattener & reducer (f/5)
    • Camera: Canon 60Da
    • Light Frames: 12, 5-min. exposures stacked
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time: 60 min. (12 x 5 min.)
    • ISO: 800
    • Processing: Photoshop CC
    • Imaging Location: Sierra Nevada Mountains (Altitude: 8,600 ft.)

    The  Andromeda Galaxy (M31) is about 2 1/2 times larger than our Milky Way and contains an estimated 1 trillion stars. At a distance of 2.5 million light-years, it is our nearest galactic neighbor and getting closer to us every day at nearly 70 miles per second. But even at that speed, our galaxy won’t collide with Andromeda for at least another 4 billion years. So don’t hold your breath.

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    North America Nebula

    North America Nebula

    North America Nebula (NGC7000)

    • Telescope: Stellarvue SVA130T-IS
    • Mount: Losmandy G-11 with Gemini 2 controller
    • Autoguiding: Yes (sub-arcsecond rms accuracy)
    • Optical Configuration: 0.72x field flattener & reducer (f/5)
    • Camera: Canon 60Da
    • Light Frames: 12, 6-min. exposures
    • Calibration: None (no darks, no flats, no biases)
    • Exposure Time: 72 min. (12 x 6 min.)
    • ISO: 800
    • Processing: Photoshop CC
    • Imaging Location: Sierra Nevada Mountains (Altitude: 8,600 ft.)

    The aptly named North America Nebula (NGC7000) in the constellation Cygnus is an emission nebula containing gasses that glow red or blue. The red color comes from hydrogen gas that absorbs light from nearby stars and re-emits it in the red part of the spectrum (hydrogen-alpha emission). The blue light comes from oxygen gas, which also absorbs nearby starlight but re-emits it in the blue. The effect creates a purple haze glowing amid thousands of stars.

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