Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: hot to spot alpine subsuns

  1. #1
    Join Date
    May 2006
    Location
    Madison, NH...avatar: King of the Pemi
    Posts
    607
    Thanks
    33
    Thanked 126 Times in 45 Posts

    Default hot to spot alpine subsuns

    http://www.spaceweather.com/swpod200...ien4_strip.jpg


    looking for a silver lining to this weather, I'd like to see/photograph an alpine subsun. Does anyone know more about this and more about how to spot one? What are the optimal conditions, temperature, what direction, what time of day, etc.?

    Judging by the shadows and literature, they appear in the direction of the sun.

    http://www.spaceweather.com/archive....2009&view=view

    Thanks for any help
    Last edited by forestgnome; 01-16-2009 at 09:11 AM.
    nature photography of the White Mountains
    by Patrick LaFreniere
    new site: www.pbase.com/myworld

  2. #2
    Join Date
    Oct 2006
    Location
    Connecticut
    Posts
    2,679
    Thanks
    7
    Thanked 32 Times in 28 Posts

    Default

    I've seen these skiing out west, CO and UT. Always on the first chairlift ride in the morning when the air is filled with ice crystals.

    I'm not sure what is happening. On clear, cold mornings with no clouds in sight condensation will condense and precipitate out of the air.
    Bill
    Next up: Vermont City Marathon: May, 2011
    EasternLight

  3. #3
    Join Date
    Aug 2007
    Location
    Mount Washington, NH
    Posts
    362
    Thanks
    7
    Thanked 110 Times in 42 Posts

    Default

    I am trying to think of the last time I saw one out here and nothing immediately somes to mind. Growing up out west, I saw them a few times though. They appear directly below the sun at equal distance as the sun is high. They are most favorable a few hours after sunrise or before sunset and must be below your field of plane (ie, summits, chairlifts, etc) but if in a airplane, they can occur at any time of the day. They are formed by a reflection off small plate shaped ice crystals that are "falling" parrallel to each other to create a mirror like effect. The more parallel they are, the sharper the image. They are most commonly found in freezing fog, arctic cold (like the temperatures over the northeast right now) as the air is so cold, small ice crystals form, or in high, thin cirrus clouds. It is similar to the process that forms halos and sundogs.
    Ryan Knapp
    Staff Meteorologist/Night Observer, KMWN (Mt Washington Obs., NH)

  4. #4
    Join Date
    Sep 2006
    Location
    Maine
    Posts
    6,247
    Thanks
    112
    Thanked 398 Times in 250 Posts

    Default

    Here is a picture i took a while ago of a sun pillar.

    Brad (a 6288 club member)
    http://bradstreet.zenfolio.com Personal Photo sales site
    http://public.fotki.com/bradbradstreet Personal photo web site
    http://public.fotki.com/MWO/saved/2012/ MWO image & video archive site 2006-2012

  5. #5
    Join Date
    Oct 2006
    Location
    PA
    Posts
    2,144
    Thanks
    541
    Thanked 121 Times in 73 Posts

    Default

    brad i saw something like that this morning .the sun was not showing yet but right where it was starting to come up there was this ray of light coming up off the top of the sun . then when the sun came up it was still there for for some time ,i wish i had a camera then
    i will have one next time
    i am a Summit Club member
    http://public.fotki.com/hvachawk/new pictures and videos

    If your not a OBS member yet then what are you waiting for

  6. #6
    Join Date
    Jan 2007
    Location
    Wahiawa, HI
    Posts
    2,359
    Thanks
    5
    Thanked 9 Times in 5 Posts

    Default

    Nice shot, Brad.
    Steve
    Is there really any BAD weather???

  7. #7
    Join Date
    Sep 2006
    Location
    Maine
    Posts
    6,247
    Thanks
    112
    Thanked 398 Times in 250 Posts

    Default

    I saw it - took the picture - but did not know what it was till later.
    Brad (a 6288 club member)
    http://bradstreet.zenfolio.com Personal Photo sales site
    http://public.fotki.com/bradbradstreet Personal photo web site
    http://public.fotki.com/MWO/saved/2012/ MWO image & video archive site 2006-2012

  8. #8
    Join Date
    Oct 2006
    Location
    Connecticut
    Posts
    2,679
    Thanks
    7
    Thanked 32 Times in 28 Posts

    Default

    Quote Originally Posted by Brad View Post
    Here is a picture i took a while ago of a sun pillar.
    Nice sun pillar, but not the same as a subsun...of the alpine variety.
    Bill
    Next up: Vermont City Marathon: May, 2011
    EasternLight

  9. #9
    Join Date
    Jul 2007
    Location
    Epping, NH
    Posts
    657
    Thanks
    8
    Thanked 58 Times in 25 Posts

    Default

    As Ryan stated, subsuns are reflections of the sun off of the top of plate crystals. Crystals tend to form in clear air under fair conditions in temps below zero, typically though you need to be below -10F to form them.

    A good discription of the path of light can be found here:
    http://www.atoptics.co.uk/halo/subsun.htm

    How to spot them...well, they are rare...I've only seen them a few times on the summit. They are the same distance below the horizon as the sun is above, so an early or late sun is better...

    Also of note, the crystals that form in extreme cold can do other neat things, like near halos, near sundogs, and light pillars from street lights. If you check out spaceweather.com today, there are examples of these displays, including one from whitefield, NH.

    Here's my only subsun pic...
    "I've learned that everyone wants to live on top of the mountain, but that all the happiness and growth occurs while you're climbing it."
    ~Andy Rooney

    Follow my photography on Facebook:http://www.facebook.com/pages/Jim-Sa...y/156147782386

  10. #10
    Join Date
    Sep 2006
    Location
    Maine
    Posts
    6,247
    Thanks
    112
    Thanked 398 Times in 250 Posts

    Default

    Great picture and it helps us understand what it is.
    Brad (a 6288 club member)
    http://bradstreet.zenfolio.com Personal Photo sales site
    http://public.fotki.com/bradbradstreet Personal photo web site
    http://public.fotki.com/MWO/saved/2012/ MWO image & video archive site 2006-2012

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •