Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Stargazing Large sunspot visible

  1. Apr 12, 2016 #1

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    over this week a very large single spot has been traversing the solar disk
    will still be visible for another 3-4 days

    This was taken today .. 13 Apr 2016
    f/l 800mm, 500th sec, ISO 200, f7.1 (plus whatever the solar filter added lots and lots :smile: )
    The filter ( commercial one that I use) cuts out around 99.99% of the light from the sun

    IMGP1312sm.jpg
    IMGP1312 closeup of spot.jpg


    cheers
    Dave
     
  2. jcsd
  3. Apr 12, 2016 #2

    phinds

    User Avatar
    Gold Member

    Wow. That thing must be huge. Several times the Earth's diameter, right?

    Nice photography.
     
  4. Apr 12, 2016 #3
    Looks like something that should be checked out by a doctor :biggrin:
     
  5. Apr 12, 2016 #4

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    thanks, phinds :smile: It's my 150 - 500mm tele-zoom on my Pentax K5 crop sensor camera = somewhere around 840mm equivalent f/l on a full frame camera

    Yes, They are saying around 2-3 earth sizes

    D
     
  6. Apr 12, 2016 #5

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    Haha ... hmmmm does have that melanoma look to it huh :-p


    Dave
     
  7. Apr 13, 2016 #6

    Andy Resnick

    User Avatar
    Science Advisor
    Education Advisor

    Got a few good images this morning- this one is 'normal', using only an ND4 metallic filter, original is 1570 x 1570 pixels: 800mm f/8, 1/200s ISO 80

    DSC_4620-1_zps4rsmfh9y.jpg

    And a zoom on the sunspot, using the red channel of an image taken with ND4 + Schott BG3 filters (I don't own any proper line filters):

    BG3_red%20channel-crop_zpsrisovmue.jpg

    I think davenn is upside down :)
     
  8. Apr 13, 2016 #7

    phinds

    User Avatar
    Gold Member

    Yes, I have long suspected that might be the reason ...
     
  9. Apr 13, 2016 #8

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    Dave
    nice one Andy, thankyou for sharing and adding to the images :smile:

    nor do I, a narrow band solar telescope has been on my to buy list for many, many years ...
    high price for minimal use has always been the stopper

    hahaha :-p :smile:


    Dave
     
  10. Apr 14, 2016 #9

    Borg

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    Where do you guys get those filters? Do they come in standard sizes and fittings for most camera lenses? I would like to get some practice before next year's eclipse.
     
  11. Apr 15, 2016 #10

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    have a look at my latest post in that eclipse thread, I have a link
     
  12. Apr 15, 2016 #11

    Dotini

    User Avatar
    Gold Member

    From today's edition of spaceweather.com

    SOLAR RADIO STATIC:
    Giant sunspot AR2529 is making noise, and it sounds like static. On April 14th, amateur astronomer Thomas Ashcraft heard a gentle crescendo of noise emerge from the loudspeaker of his shortwave radio telescope in New Mexico. "It was a Type III radio burst from the sun," he says. Click to listen (the static surges about 20 seconds into the audio file):

    static_strip.png

    Type III radio bursts are caused by solar flares. Electrons accelerated by magnetic explosions race through the sun's atmosphere, causing a ripple of plasma waves and radio static. Sunspot AR2529 has been crackling with C-classflares, almost non-stop, and these are apparently the source of the static.

    "The burst was recorded in stereo using two separate short wave receivers, one tuned at 20.030 MHz and the other at 21.119 MHz. Best listened to with headphones," says Ashcraft.
     
  13. Apr 18, 2016 #12

    Dotini

    User Avatar
    Gold Member

    From today's edition of space weather.com

    BIG SUNSPOT ERUPTS:
    Surprise! Quiet sunspot AR2529 isn't so quiet, after all. The heart-shaped active region erupted on April 18th (00:39 UT), producing a strong M6.7-class solar flare. NASA's Solar Dynamics Observatory recorded the flare's extreme ultraviolet flash:

    m6_strip2.jpg

    A pulse of UV radiation from the flare ionized the top of Earth's atmosphere. This, in turn, disrupted shortwave radio communications over the daylit side of our planet. Mariners, aviators, and ham radio operators around the Pacific Ocean may have noticed fading signals at frequencies below ~15 MHz. A NOAA blackout map shows the frequencies and territories affected.

    More M-class flares are possible in the days ahead. AR2529 has developed a 'beta-gamma' magnetic field that harbors plenty of energy for this kind of explosion. Although the sunspot is no longer directly facing Earth, it can still affect our planet by causing radio blackouts and glancing-blow CMEs.
     
  14. Apr 19, 2016 #13
    Is that something related to alien???
     
  15. Apr 19, 2016 #14

    OmCheeto

    User Avatar
    Gold Member

    ??????

    Oh. Now I get it. But it was "Alien Resurrection", and not "Alien".

    sunspot.eruption.looks.like.alien.cover.photo.jpg

    :biggrin:
    ........
    :redface:
     
  16. Apr 19, 2016 #15
    What???
     
  17. Apr 20, 2016 #16

    Dotini

    User Avatar
    Gold Member

    From today's edition of spaceweather.com:

    BIG SUNSPOT DEPARTS:
    Yesterday, giant sunspot AR2529 unleashed a powerful M6.7-class solar flare. Today, the sunspot is leaving. AR2529 is approaching the sun's western limb where it will soon disappear from view. Maximilian Teodorescu sends this parting shot from Dumitrana, Romania:

    partingshot_strip.png

    "I took this picture using a solar-filtered 8 inch telescope and an ASI 174MM digital video camera," says Teodorescu.

    When AR2529 leaves the solar disk, the odds of a geo-effective flare will plummet and the solar cycle can continue its plunge toward Solar Minimum.
     
  18. May 3, 2016 #17
  19. May 3, 2016 #18

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

  20. May 4, 2016 #19
    That is unfortunate!, I would be happy to trade places with you for the event.:smile:
     
  21. May 4, 2016 #20

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    I seem to remember reading that sun spots occur in pairs. Where would be the other half? Or is it all within the same region, in this case?
    A bit of luck. The other day, I was getting my finder scope ready for projecting an image of the Sun on a white card, in an attempt to see the transit of Mercury next week and I saw that enormous sunspot. Just a single one and very impressive! I should look more often. Then I happened to look on the astronomy forum and saw this thread title. The only other ones I have seen have been really feeble little blemishes compared with that big mother.
     
  22. May 4, 2016 #21

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    in this case all within the same region ... if you look at the close ups of the photos by Andy and myself and then the commercial image from dotini, you can see that the main spot is segmented

    well done ... good to hear you are getting the scope ready for the transit :smile:
    Uh huh, was the biggest spot region I had seen for a very long time

    you should invest in a solar filter .... maybe an astronomy shop near your location has one of these brands ....

    http://www.bintel.com.au/Accessories/Solar-Filters/128/catmenu.aspx [Broken]

    I have 2 of them .... a smaller one that fits the telephoto lens for the camera .... used to take the image in post #1
    and a much larger one the covers the whole front of the telescope, so that I can visually observe and if wanted,
    do photography of the sun through the scope.
    Many years ago, I used to do eyepiece projection from the scope onto paper and hand draw the spots
    I would stop the light down from entering the scope by putting a piece of cardboard with a ~ 2 - 3" hole in it
    rather than the full 8" aperture of the scope. This increased the F stop substantially and reduced the light and heat
    intensity sufficiently to minimise the possibility of damage to the telescope optics.


    Dave
     
    Last edited by a moderator: May 7, 2017
  23. May 4, 2016 #22

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    Oh, right. The multiple bits of that picture are obvious no I think about it.
    That's more than half what I paid for the 'scope!!!!! My life. Nice idea but. . . . . .
    I found the Beehive Cluster tonight and a very faint blur which I think was the Pinwheel Galaxy. But the PG is right next to the big dipper so it won't be seen very often in your parts, I guess.
    I could do the big f stop on the Dobs, I guess but I have heard so much about problems with the Sun roasting bits inside reflectors that I would need it stuck on very reliably.
     
  24. May 4, 2016 #23

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    Those are AU$ prices ..... what make and model scope do you have ?
    They really are VERY GOOD emphasis intended :smile:

    The pinwheel galaxy = M101 in Ursa Major ( the big dipper) never gets above our horizon

    an added advantage with increasing the f-stop is that it also improves the image sharpness :smile:

    for visual use to observing the sun, if you cannot afford a commercial solar filter, is to use a mylar survival blanket available from camping/outdoor stores

    sh77ml350.jpg
    only a few bucks/pounds ( your choice of currency)

    still stop down the aperture with a smaller hole, then across that hole use several layers ( 3 to 4 usually enough) it makes an effective visual and photographic filter for direct solar viewing
    I have often stretched several layers directly across the end of my camera telephoto lens and taped in place ... also works well

    Dave
     
  25. May 4, 2016 #24
    Awesome! Thanks for the info. I had no idea.
     
  26. May 4, 2016 #25

    davenn

    User Avatar
    Science Advisor
    Gold Member
    2017 Award


    you are welcome :smile:
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted