100 Hours SunDay

UPDATE: The 100Hours already occured. Check out the official webpage for reports.
It was a great overwhelming success. Thank you!
And remember the IYA2009 is not over!

100 hours of Astronomy is a 100-hour (from the 2nd to the 5th of April 2009), round-the-clock, round-the-globe event inside the International Year of Astronomy.


It consists of a wide range of public outreach activities, live science center, research observatory webcasts and sidewalk astronomy events. Events are mainly focused on the wonders of the starry night, but there are also events all around the world to observe the crescent Moon for early observer, and of course daytime observations of the Sun.

This Solar TG collaborates with 100 Hours, supporting any activity related to the Sun, and providing instructions, ideas and recommendations for safe solar observations.

And Sunday might perfectly be the best day for a solar event. Star parties on Sunday are difficult since everyone has to get up early for school or work. Let´s enjoy the Sunday, when everyone has free time and kids and adults can all enjoy the near but forgotten Sun and its wonders. Either get up early to start with a nice sunrise, go for a walk on the afternoon or enjoy a wonderful sunset. On the meantime you can participate on a 100 hours solar event. Ask your local astronomy center for more information. If you are an astronomy center, let´s organize one event!. There is no need to restrict it to the Sun, you can event start at sunset and continue with some star gazing…

Let the last day of 100 Hours be the Sun day, not just a Sunday.

For that reason, this page, and on the 100 hours website, we will be encouraging and helping everyone to organize their solar events this day. Here you can find, ideas, resources, experiments. Leave us our comments or ask us any question you might have.

Create your event! The perfect venue is outside, sunshine permitting.
  • Always when observing the Sun, follow and educate everyone with safety instructions.
  • Set up a telescope with a Solar filter, withe white light of H-Alpha.
  • Create a pinhole camera to image the Sun, or better make a workshop to build your own pinhole camera.
  • Talk, talk, talk. There are many many topics to talk about our Sun. Speaking about any of them, keeping the live shining reference above us, greatly helps to put closer the wonders and distant worlds of Astronomy. See below for a tentative lists of topics.
  • There are many experiments to carry on, like
    Measuring the Sun size, and others.
  • Make a solar system play with kids (to talk about distances, speeds, sizes, space missions, …
  • Construct an spectrometer with a CD.
  • Show the photoelectric effect, use sun panels, talk about Solar energy.
  • Make coordinated pairs of observations around the world to measure the Sun-Earth distance, or the Earth radius.

Take a look on our resources sections, there you can find links th more activities and experiments, as well as links with even more activities.

Indoors or outdoors, a thematic talk can be a very instructive idea. You can decide to do it just with your voice, or use media materials, like photos or videos (see below for references)

Thematics ( Brainstorming )
  • Scales of the Sun, its dimensions, distances, inner parts, …
  • Safety and the Sun. Observing the Sun, UV light, …
  • Living on the Sun´s atmosphere, influences and safety and dangers due to the heliosphere.
  • Space Weather: How the Sun can greatly influence the Earth. Magnetic storms, effects on technology, past solar maxima, dangers and protecting of the Earth´s magnetosphere.
  • Current research efforts, satellites observing and serving live image of the Sun from many viewpoints.
  • Current biggest misteries of the Sun, like the coronal heat.
  • Use the Sun to talk about the life of a star.
  • Talk about anecdotes related to the Sun, like the Carringtongs flare, the nuclear false positive,  the little-ice ageVancouver black outtelegraphy on the Sun batteries, proof of Einstein theories during an eclipse, the discovery of the Helium, …
  • The Sun in history (from nature, life, to mythology, astrology, … )
  • What if? cases: How would humans look like, or exists, if the Sun, were a bit bigger, closer, fainter, more active, calm, emitting more in X-rays or infrareds than on “Visible”, had a companion, Jupiter as a Sun…
  • The brother Sun: The Sun and us, we all come from the same dust of a previous father Star.
  • Ask an astronomer: Open tables to talk about the skies
Play some on the zillion on movies or documentals about the Sun, eclipses, …
Show the Live view from the Sun, like from Stereo, Hinode, Soho. Use videos of the Sun (Best of Soho, Hinode, Stereo, Trace),  from the National Geographic, … (take a look to the resources pages for more links or send us your links!)
Ask your planetarium or science museum to prepare an astronomical event on that day.


  1. [...] da Astronomia: 100 horas de Astronomia (veja também o blog). Culminando no último dia com um dia dedicado ao Sol, este evento conta com milhares de actividade espalhadas por todo o mundo. Portugal não será [...]

  2. hello i’am from astronomy and space club sidi bourouis town ( tunisia)
    Observed our star,The star which gives us the life , is a pleasure for us, through soho will be more .
    so sunday in our club ,we will see the sun .

    I thanks you infinitely soho

  3. I´m from Brazil. It is possible to love the Sun 365 days/year. Thanks for this.

  4. I love the sun too, it brings me all kinds of awesome colours and effects in the ice crystals and clouds, and I love to share my images of those effects.

    We will run a sun day on April 5th and share the sun with the public here in Wellington.

    The sun also brings us aurora, here it is called aurora australis, or rakiura, great glowing of the sky!!

  5. Happy IRANIAN new year named NOWROOZ to you.
    I’m from BOJNURD of IRAN, about 10 years ago, we had an eclipse on ISFAHAN. we recognized and managed about 90 school & Univ. students, a PC, an 2″ Telescope for recording the eclips & be able to show at Monitor on ISFAHAN IMAM Sq.
    also about 3 years after this, we had similar project for Venus passed through the sun.
    and next year we had a patricidal eclipse at the SABZEVAR city. And next days, for Sunday, we have films, papers, slides, and more about the our unique star, the SUN.
    also we obtained the solar filter and broadcast the sun on data projection via the our telescopes, at the our 100 HA programs, on 5 venues.
    Read more at: http://www.IYUA.40sotoon.com please, and help to have more efficiency and ability for this opportunity. Thanks again.
    It’s would find very wonderful, when we can watch the solar points, but it’s impossible at this years. Also we can show the SUN film, or give them the WEB addresses for read and find more about the SUN, and we can do it, with you.

  6. I love the the hugh ball of gases that constantly gives us light and heat

  7. we can do the SUNday at sunday, and all aof day times on 100HIYA’s program. we capture the sun via filter and 10″ optical telescope, show this images trough the data projection to passengers and other citizen that passes final of NOWROOZ holiday at BABA AMAN, BESH QARDASH, RHADAR KHANE ye AMIN o ALLAH, SHAHR e BAZI and Students Research Center (PAJOOHESH SARA).

  8. We are already celebrating the IYA since 1st January, 2009 and we have also arrange public viewing and participation during 100 hours of astronomy from 2-5th April. On 3rd April we are showing live webcast on big screen for all. On SunDay, we are arranging few telescopes at Modhera Sun Temple in our state : Gujarat, which is famous temple. Here we are displaying few posters giving detail understanding of the Sun as well as Solar System’s different bodies.

  9. We are already celebrating IYA 2009 since 1st January by conducting astronomy awareness programs at schools and institutes. We have also arranged telescopic viewing and poster display during 100 Hours of Astronomy from 2-5th April. On 3rd April we will be showing webcast on big screen and on 5th April i.e. SunDay, we are arranging unique program of Solar observation from famous Sun Temple at Modhera.

  10. [...] 100 Hours SunDay [...]

  11. One suggestion to supplement the education activities involving the scale of the Solar System is to get the participants in the model to attempt to walk at the speed of light. I usually start by trying to explain the speed of light by showing them a 300mm (12″) ruler and explaining how light travels this distance in a billionth of a second. I then try to explain what a billion is – quite difficult in practice. I then get people to practice walking 1m at the scale speed of light – they find it quite difficult ! You can also ask them to try walking to the Sun in 8 minutes. Intersperse this with some facts about the pathetic speed of our space probes and about how long it would take to get to the Sun by spacecraft and they begin to get some idea of the scale of the Solar System. You can then speak about the journey times to the outer planets. You probably need to allow them to walk to the outer planets at above the scale speed of light. It’s worth making an estimate of how fast people are actually walking in terms of the speed of light.

  12. On behalf of Sabitri Debi Institute of Technology we are celebrating IYA 2009 by some awareness programs and starting a distance mode astronomy course for elementary level. We are going to organise a sky watching camp in our institute’s premises. Sun is our favourite object. 0n 3 April, 2009 we will observe the Sun whole day.

  13. tooo… beautiful

  14. On behalf of the Sidewalk Astronomers Philippines and the Astronomical League of the Philippines, we will be participating in the 100HA and the SUNday on April 5. The event will be held at the parking lot of the Boardwalk adjacent to the Manila Oceanarium in Manila. Open and free views of the Sun will be given free to the public.

  15. The FREE PUBLIC VIEWING SESSION in the Philippines for SUN Day will start at 1pm and end at 4pm (April 5). Hydrogen Alpha filters and Mylar flters will be used to give the public safe views of the Sun. Again, the site is at the parking lot of the Boardwalk adjacent to the Manila Oceanarium.

  16. [...] Saturday is the 24 Hour Global Star Party which will take place at thousands of sites around the world (check your local listings for a site near you).  Wrap up the weekend with Sunday, dedicated to the Sun. [...]

  17. [...] an opportunity for the public to take images with remotely controlled telescopes online; and “Sun Day” (April 5), a celebration of our home star, with an emphasis on safely observing the [...]

  18. [...] dikkat çekmek için DAY2009 Güneş Fiziği Görev Grubu, 5 Nisan Pazar gününü “Güneş Günü” ilan etti. Bu nedenle bazı etkinliklerde, bu gün için, özel Güneş gözlemlerine yer [...]

  19. Hello everyone of this world!
    My blog:http://ameblo.jp/bluecoloreye/
    I am a science fiction writer! Enjoy exploring the universe!
    Writing is a science fiction, welcome you to my blog!
    I put forward the idea: God is DNA! ~
    Do you think so? :)

  20. SolarLive: Experience our nearest G2V class star, the Sun. Live from Zwolle, the Netherlands.

    Live broadcasting with a b/wToU webcam and Solar telescopes.

    You can watch dark sunspots come and go, surrounding area’s of plage, magnetic filaments, erupting prominences and occasionally, some outbursting flares.
    Live streamed in the light of H-alpha and Calcium-K lines.

  21. Hello people! Want a bit of science? If you want, here it is.
    I am a Hubble fan and I love/like Huble.
    I allready know about the Orion nebula, the sombrero nebula, the mice galaxies…
    Have fun!!!!!

  22. Congratulations, this is a great opportunity to enjoy the wonderful universe.

  23. We at Regional Science Centre & Planetarium, Calicut are organising numerous public observation event, sideway astronomy observations, astronomy exhibitions, sun observation camps, slide show, film show amd much more.

  24. Association of Bangalore Amateur Astronomers will be conducting Solar viewing and Telescope viewing for general public on 5th April Sunday at
    Jawaharlal Nehru Planetarium in Bangalore as part of 100Hrs of Astronomy which is a global event. ABAA a 35 year old Astronomy association will be putting up telescopes for the general public for Solar viewing follow by Night sky observations. ALL ARE WELCOME.

  25. [...] Note: Follow the Sun today as part of 100 Hours of Astronomy [...]

  26. [...] 100 Hours SunDay [...]

  27. Amateur Astronomers Association of Kurdistan/Iraq is waiting wright now for a liitle chance of a Sun apearing through clouds here in Erbil city at early morning of April.5.2009.
    We will using our 8″ Meade LX200 with solar filter and Coronado Personal Telescope for this perpose.
    Tere was a heavy showers with thunder storms just on the night of ISAN3!. We hope with a little luck to participationg with the world on this wonderful day and saying too much about our nearest dearest star to the sidewalkers and amateur astronomers of this city.

  28. [...] us with any of the many events from 100 hours of astronomy today, or the ones commented on our Sun Day page, or follow the instructions to create your own event. You decide, but please, remember [...]

  29. we at SPACE (Science Popularization Association of Communicators and educators) INDIA, have been doing observations of the sun at the masonic observatory “jantar Mantar” specially during the 100 hours of astronomy. During the event, we educated hundreds of kids and adults about the variuos techniques to observes the sun safely and how to find the position of the sun in universal and local coordinates by using the instruments of the observatory in the heart of New Delhi

  30. “If not for the sun…..we would not be.” One of my yoga teachers repeats this mantra. The gayatri mantra pays homage to the sun…”may the orb of the sun, that bright spot, kindle the fire of my intellect.

  31. Past the great becon
    With planets and moons
    Gently nestled,
    Dangerous, because of space folds
    Where one can be trapped
    Or wander lost for millennia
    Never arriving
    “No one will find us here”

    Vialetti is a rogue entity, capable of taking matters into her own elements,for the good of all concerned…

    HI, I am a fiction writer, presently writing a fiction piece for young readers 9yrs and up

    It is called “Ancient Memory”


  32. It seems good that the Sun should be the last object of our attention as the 100 Hours Of Astronomy nears the end of it’s celebreation!
    The world would not continue in any form without the Sun and we owe a great debt to the time we have been given to know these things we are learning.
    We, here in Joshua Tree get lots of Sun!
    Thanks for a great event with the international community of enthusiasts for the interest in the sky, above, and the shared experience we have enjoyed together!
    Sincerely, scdva

  33. It’s been more of a months worth of activity for my club I serve as president of, we started out with the following and then did our own community sun showings sharing with the people we live around, ending last night together at the museum where we meet for the club having and Moon and Saturn Party.

    Now back to the kick off;
    San Bernardino Valley Amateur Astronomers’ (SBVAA) President James Butts, announces that Dr. Edward J. Rhodes PhD. Collaborating Professor in the Department of Physics and Astronomy at University of Southern California, (USC) will speak at the San Bernardino County Museum of Natural History for the clubs March 21st meeting. All monthly meeting are open and free to the public, starting at 7:00 pm located at 2024 Orange Tree Ln, Redlands.
    Dr. Rhodes shall speak about the research that he has carried out at NASA JPL this past year on the feasibility of having future lunar astronauts place a solar observing instrument on a mountain peak near the lunar South Pole to observe the Sun for the prediction of solar energetic particle storms, which could be hazardous to the astronauts’ health and safety.
    Dr. Rhodes leads an active program in both ground- and space-based observational helioseismology. One of the pioneers in this field of solar physics he is a NASA-selected Co-Investigator on the Solar Oscillation Investigation (SOI). The SOI-Michelson Doppler Imager flys onboard the NASA-ESA Solar and Heliospheric Observatory spacecraft. Dr. Rhodes is the Principal-Investigator for the 60-Foot Solar Tower at Mt. Wilson Observatory and the High Degree Helioseismic Network (HiDHN). This network onsists of a second station in Ukraine, at the Crimean Astrophysical Observatory. HiDHN provides nearly continuous observations of the sun during the summer months. Beginning in 1992 Ed Rhodes served as a Guest Computational Investigator in the NASA High Performance Computing and Communication Program. As part of this program he and his group employed several NASA-supported supercomputers located at Caltech and at JPL. These computers are still used in addition to a network of dedicated workstations located both at USC and the 60 Foot Solar Tower.

  34. When I was 7 years old (1949) I conducted an experiment to get a feel of the distance from Earth to the Sun. Using our playground at school and a basketball for the Sun (about 9″ diameter), I placed the sun in the center of the playground. Mercury (a bee-bee) was about 30 feet away, Venus (bigger bee-bee) at 60 feet and Earth was placed at 86 feet. (I still have my notes from that).

  35. Hello beloved my Sis and Bro in this world!

    I put forward the idea: God is LOVE…..LOVE is GOD……

    Do you think so?

  36. My Sun Day activities included showing 75 people in my town the sun through two solar telescopes. One is my homemade f/10 sun scope made in John Dobson’s telescope class in about 1985. tho other is a Televue Ranger on an Telepod alt az mount, with a Corolnado Solarmax T-60 mm h-Alpha filter. Great prominences in H-ALpha, no spots in visible. Here is an article I wrote about solar sidewalk Astronomy – it is on the SOHO Outreach website http://soho.nascom.nasa.gov/outreach/past/Sidewalk/

  37. The Sun Day of the dramatic Sunday!

    The Sun Day activity in Iraqi Kurdistan Region

    With a very good luck,AAAK made it’s Sun Day event right after a thick layers of Cumulus clouds went from our skies and it lifted a magnificent clear weather behind!.

    Very quick and in hurry, we take our telescopes outside the office building 2 hours before Sun disappeared from that very blue sky with some awesome cotton like pieces of Cumulus’s!

    The location was the large square land in front of our office building, there was no enough time to take the telescopes to a park or crowd location, the time was running!
    After setting the solar filtered Meade LX 200 and Coronado P.S.T very close to the sidewalk of Erbil-Kirkuk main road, peoples watched to telescopes and sure they came to see what are going on there!? After they get close enough they involved into the activity and start watching at the nearest star without any eye harmful, the white solar disc inside the Meade was fantastic even without any phenomena like sunspots or prominences, still the image was dramatic when little patch of clouds start passing in front of the bright disc of the Sun! …It was just like we are waiting and watching a solar eclipse!

    Also the Sun was too quite even with the P.S.T , but too many questions from the side walkers and amateur astronomers of AAAK was about the invisible activities of the Sun, the answers shocked most of them! Specially who are away from astronomy but like to listen and know more about it!

    There were more than 80 participants between 04:00 to 06:00 pm (16:00-18:00 UT)
    Before the Sun sinking very dramatically behind a large patch of a Cumulus cloud.

    Another unforgettable day with our Sun and its marvels show at that very special Sunday of this perfect astronomical year!

Leave a response

Your response: