What is this rapidly twinkling red, blue, and white star I saw?

  • Last night, I was on my balcony at 1AM (PST) and I looked up and saw two stars near the horizon (I'd guess ~30 degrees above the horizon), and they were "twinkling" about twice as fast as other stars higher in the sky, and I could clearly see them changing from red to white to blue repeatedly. Other stars in the sky only appeared white to me, and didn't seem to "twinkle" as rapidly as these two stars did. The red and blue make me think of red-shift and blue-shift, but I don't know how I would see both from the same object.

    What was I seeing?

    I don't know if it helps, but I am in the Los Angeles area, and I was looking in a roughly north direction. almost exactly to the east, according to google maps.

    Edit: I tried taking a picture, but light pollution from the nearby street lights wouldn't permit me taking a decent picture. However, I noticed a group of three stars close together in nearly a perfect almost vertical line, and managed to find that in Stellarium. I think I found the two stars I am seeing: Procyon and Sirius

    What I found in Stellarium

    Is there anything about either of these stars that would make them show as red/blue?

    Can you specify how far apart these two stars were? A good metric would be to use the width of fingers or your hand at arms length. E.g., the two stars were three fingers apart when held at arms length.

    (in case this is not obvious) The same stars will be there tonight (for at least a month or two) at almost exactly the same position. If they have gone, then you didn't see "stars" you saw aeroplanes or Halloween lanterns or something else.

    @JamesK I stared at the stars for about 5 or 10 minutes, they never changed position. They were also too high in the sky to be any sort of decoration. I'll take a picture tonight, hopefully my camera can do a high enough exposure to capture the light from the stars.

    Ha, go figure. Check the last sentence in this section on wikipedia

    You can install the application 'Star Walk 2' on your iPhone, or on Android Phone from App Store. It's one of the best apps for observation of night sky. It may help you to identify most of the bright objects in the night sky.

  • Dr Chuck

    Dr Chuck Correct answer

    5 years ago

    It's most probably Sirius. At this time of year (at 1 am local time) it's low in the sky in the East, so there is a lot of atmosphere in the way, and as Sirius is a bright bluish star, it will show all the colours described as it twinkles.

    @JamesK Sirius seems to be the right answer, at least one of the two I was seeing. Maybe 30 degrees was a high estimate on my part... :P

    This should be the standard answer. Every year in March / April this kind of question pops up again and again - when Sirius is due south in the evening sky.

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Content dated before 7/24/2021 11:53 AM

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