20 votes

APOD - Astronomy Picture of the Day

7 comments

  1. [3]
    All_your_base
    Link
    Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. It also has an incredible archive going back...

    Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

    It also has an incredible archive going back several years.

    Just sharing an old favorite for anyone who hasn't seen it.

    7 votes
    1. [2]
      chocobean
      Link Parent
      Hi OP, your link pointed to the main gallery, which shows today (12 June 2023)'s picture, of "The Largest Satellites of Earth " -- could you try again with your old favourite? I'd like to see what...

      Hi OP, your link pointed to the main gallery, which shows today (12 June 2023)'s picture, of "The Largest Satellites of Earth " -- could you try again with your old favourite? I'd like to see what it is : )

      and you weren't kidding, the archive is incredible.

      2 votes
      1. All_your_base
        Link Parent
        By "old favorite," I meant the APOD site is an old favorite. There are younger folks as well as those newer to astronomy. I wanted to both notify the new and remind the old that it existed....

        By "old favorite," I meant the APOD site is an old favorite. There are younger folks as well as those newer to astronomy. I wanted to both notify the new and remind the old that it existed.

        Picking a single favorite picture would be like trying to pick a favorite pun in the Airplane! movie, or the best joke in Blazing Saddles.

        5 votes
  2. [3]
    TransientSignal
    Link
    Relating to the APOD from today (June 12th) - If you ever think that you'd like to try to either observe or to capture the ISS transiting the Sun or the Moon, check out this site:...

    Relating to the APOD from today (June 12th) - If you ever think that you'd like to try to either observe or to capture the ISS transiting the Sun or the Moon, check out this site:

    https://transit-finder.com/

    Transits are not frequent at any given particularly location, but if you keep looking every few weeks you're bound to eventually find one happening in your area. I've been keeping an eye out on and off for about the past 7 years and have managed to both observe a Solar transit of the ISS with my own eyes and to capture a Lunar transit of the ISS. A telescope obviously helps, but just a pair of binoculars (for a Lunar transit, don't look at the Sun with binoculars unless you have a Solar filter!) should be adequate.

    2 votes
    1. [2]
      All_your_base
      Link Parent
      And if you want to see exactly where it is there is an ISS live tracker map There are also live views, such as the HDEV - High Definition Earth view and Internal views on Ustream. I kinda stopped...

      And if you want to see exactly where it is there is an ISS live tracker map

      There are also live views, such as the HDEV - High Definition Earth view and Internal views on Ustream.

      I kinda stopped watching those a few years back. I had many friends around the world, and was upset when they turned off the live chat and I lost track of them.

      2 votes
      1. TransientSignal
        Link Parent
        Another great resource from views from the ISS is the 'Gateway of Astronaut Photography of Earth'. Literally millions of photos of our little speck of dust from not only the 69 ISS missions, but...

        Another great resource from views from the ISS is the 'Gateway of Astronaut Photography of Earth'.

        Literally millions of photos of our little speck of dust from not only the 69 ISS missions, but also from every single one of NASA's manned spaceflights. I like to check the 'Latest ISS Imagery' tab once a week or so for the latest 1,000 or so photos that have been downloaded.

        2 votes
  3. the_guruji
    Link
    One of my favourite APODs is one of the Ring Nebula: https://vanderbei.princeton.edu/images/NJP/m57.html (linking to the original imager's website, which has improved versions). The light has been...

    One of my favourite APODs is one of the Ring Nebula: https://vanderbei.princeton.edu/images/NJP/m57.html (linking to the original imager's website, which has improved versions).

    The light has been passed through a diffraction grating. Every source in the sky appears undiffracted (like a normal image) and off to the left and right, you get the first order diffraction streaks. So each streak there can be matched to a normal-looking star. The stellar spectra are mostly continuous emission (there are absorption lines, but not obviously visible in this image). However the ring nebula has emission mostly from just two wavelengths here: [OIII] (around 500 nm: the cyan one) and H-alpha (about 660 nm: the red one). It's just a very obvious demonstration of how different the emission from planetary nebulae are from that of stars.

    2 votes