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Ursa Astronomical Association
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Ursa Astronomical Association

Sun - 31.3.2021 at 13.50 Tampere Observation number 97368

Visibility IV / V

Pekka Rautajoki, Tampereen Ursa

Bongaa 100 challenge target #36, star, made me wonder why I would choose. I didn’t want to record this as an automatic observation, although of course I could have done so with many other starry objects. I ended up immortalizing on paper the most important star to us, the Sun - however, it is the only star from which one can also record surface details! At the time of our observation, there was some spectacular protuberance on our chromosphere, some filaments, and a couple of Plage areas — no fireworks, but it was nice to make a drawing on a warm spring afternoon. In the second image, the spectrum of visible light from the Sun, i.e. bongaa 100 object #7. In fact, it was recorded a little later, on April 4, 2021, using the Project STAR Spectrometer spectroscope (Figure 3) and a cell phone camera. In the spectrum, e.g. the spectral line of hydrogen at 486 nanometers, the lines of iron and magnesium at 517 nanometers, and the lines of sodium at 589 and 590 nanometers. Such a simple spectroscope is an inexpensive and convenient way to analyze the spectra of various lamps and, of course, the Sun. The device is aimed at the sky near the Sun, and the spectrum consists of sunlight scattering from the sky. #bongaa100

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  • Observation target
    • Sun
    • Näyttävä
Technical information

Solar chromosphere Coronado MaxScope40 hydrogen-alpha tube with 12mm Coronado Cemax eyepiece, spectrum with Project STAR Spectrometer spectroscope and cell phone camera. Drawing: Daler & Rowney black paper, Conte and Derwent crayons.

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