Gerhana Matahari Cincin 15 Januari 2010

Hari Jumat, tanggal 15 Januari 2010 akan terjadi fenomena Gerhana Matahari Cincin. Gerhana Matahari pada 15 Januari 2010 merupakan gerhana matahari cincin (annular), yaitu bundaran bulan tidak sepenuhnya menutupi matahari sehingga masih tersisa bagian yang bercahaya, yang mengesankan seperti cincin. Namun dari Indonesia, yang bisa kita amati hanyalah Gerhana Matahari Sebagian (GMS) saja, karena tidak ada daerah di Indonesia yang dilalui oleh jalur totalitasnya, tidak seperti GMC 26 Januari 2009 yang lalu.

Daerah di Indonesia yang dapat menyaksikan gerhana nanti adalah seluruh Sumatra dan Kalimantan, bagian barat pulau Jawa, dan bagian utara pulau Sulawesi. Meskipun begitu, proses GMS akan bisa kita saksikan lebih baik apabila kita berada di wilayah barat Indonesia. Di sana gerhana akan berlangsung lebih lama dan piringan Matahari yang tertutup oleh Bulan juga lebih banyak dibandingkan dengan pengamatan di daerah timur.

Untuk pengamat yang berada di Banda Aceh, gerhana dimulai pada sekitar pukul 13.40 WIB dan berakhir pada pukul 16.40 WIB. Luas daerah piringan Matahari yang tertutupi Bulan mencapai 46% pada saat maksimumnya, yaitu pada sekitar pukul 15.20 WIB. Jumlah tersebut jauh lebih besar daripada hasil pengamatan di Manado yang hanya menutupi 0,3% daerah piringan Matahari saja.

Penjelasan lebih detail tentang Gerhana tersebut disajikan dalam artikel di bawah ini.

The solar eclipse of January 15, 2010 is an annular eclipse of the Sun with a magnitude of 0.9190. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partially obscuring Earth's view of the Sun. An annular solar eclipse occurs when the Moon's apparent diameter is smaller than the Sun, causing the sun to look like an annulus (ring), blocking most of the Sun's light. An annular eclipse will appear as partial eclipse over a region thousands of miles wide.

It will be visible as a partial eclipse in much of Africa, Eastern Europe, Middle East and Asia. It will be seen as annular within a narrow stretch of 300 km (190 mi) width across Central Africa, Maldives, South Kerala, South Tamil Nadu, North Sri Lanka, Burma and China.

Visibility

The eclipse starts at Uganda, passes through Nairobi, enters Indian ocean where the greatest eclipse is taking place in mid of Ocean for a maximum of 11 Mins and 7.7 seconds.

After that enters Maldives, where it would be the longest on land with 10.8 Min of viewing. This makes the tiny islands of Maldives the best spot for viewing this eclipse from land. The annular Eclipse at Male', the capital city of Maldives starts at 12:20:20 hrs and ends 12:30:06 hrs Maldives local time (GMT+5hrs). This is also the longest duration of any city having an international airport in the eclipse track.[1]

After that enters and exits India at Rameswaram. Only place of land under the eclipse on India. At approx 13.20 hrs IST, there is a annular solar Eclipse of sun over India. The eclipse is viewable for full 10.4 min in India. The best place from India is Dhanushkodi in Pamban Island off Tamil Nadu coast. Dhanushkodi is now a ghost town and it is about 18 km South east from Rameshwaram and 18 Km West of Mannar Island in Sri Lanka.

After Rameswaram, enters Sri Lanka at Delft Island, exits at Jaffna in Sri Lanka, cross Bay of Bengal and ends in Burma - China border. Full data is in the NASA website.

For best viewing of the Eclipse, you need to travel to Maldives, where many International flights land and take off everyday, being a world famous tourist destination. Visa for Maldives is free for 30 days for a tourist entry.

The best location In India lies between Kodandaramar Temple islet and Dhanushkodi, which falls on the central line of the Eclipse. The northern most limit of shadow in India is Cuddalore, Neyveli, Erode, Kodaikanal, Madurai. Other best locations: Trivandrum, Thoothukudi and Cape Comorin which lies 22 km north of Central line.

Only means of reaching Dhanushkodi or kodandaramar temple is by ST bus or Auto from Rameswaram and for Dhanushkodi after road's end it is only by fish carts or 4x4 SUVs. Permission is required for entering Dhanushkodi ruins from the coast guard post as that area is 10 km from Sri Lankan coast.

The centre line passes some 2 km east of Kodandaramar Temple. The exact location is between NH end and Dhanushkodi ruins. Dhanushkodi is about 2 km east of the central line. The degree difference is about 0.2 between Central line - Kodandaramar Temple and Dhanushkodi ruins vice versa. Dhanushkodi is about 5 km from Kodandaramar Temple.

Enthusiasm

People, especially the sky enthusiasts from entire India are highly enthusiast about the annular eclipse as the last total solar eclipse of July 22, 2009, being visible on Indian soil remained somewhat a frustrating experience for many of them who got clouded out on the eclipse day in Monsoon cloud. The total solar eclipse of August 11, 1999, was also similar negative experience.

Astronomy clubs from the whole country are gathering in different locations along the shadow track. One section of them, preferring to observe Bailie Beads more are concentrating on the location at the northern limit of the shadow track while the other section is going deep towards the centerline to have better view of the Ring shaped Sun.

Leave aside the sky watcher's associations from Bangalore or Chennai, even clubs like SWAN(Sky Watchers Association of North Bengal) from eastern Himalayan region like Darjeeling or North East region are also gathering in Rameswaram.

Members of SPACE (Science Popularisation Association of Communicators and Educators) and STEPL (Space Technology Education pvt ltd) have planned various observation plans for this eclipse which includes scientific studies as well as watching eclipse for a layman as a curious observer.

Sumber: NASA, wikipedia, duniaastronomi

Hujan Meteor Quadrantins - 3/4 Januari 2010

The Quadrantid meteor shower is one of the strongest meteor showers of the year, but observers can be disappointed if conditions are not just right. The point from where the Quadrantid meteors appear to radiate is located within the extinct constellation Quadrans Muralis. On modern star charts, this radiant is located where the constellations Hercules, Boötes, and Draco meet in the sky. The shower can appear almost nonexistent until about 11 p.m. Unfortunately, the radiant does not attain a very high altitude for most Northern Hemisphere observers before morning twilight puts an end to the show. The best observations are actually possible from countries with high northern latitudes, such as Canada, Finland, Sweden, and Norway. The display is virtually nonexistent for observers in the Southern Hemisphere.

The Quadrantids generally begin on December 28 and end on January 7, with maximum generally occurring during the morning hours of January 3/4. The Quadrantids are barely detectable on the beginning and ending dates, but observers in the Northern Hemisphere can see from 10 to around 60 meteors per hour at maximum. The maximum only lasts for a few hours.

Thus, the Quadrantid meteor shower is an extremely short one, lasting only a few hours. In 2010 the Quadrantids are predicted to reach a peak of about 120 meteors per hour at 1 p.m. EST on Sunday, January 3. Unfortunately, for us in North Carolina, this sharply peaked shower will not really get rolling before sunrise although a few early meteors may be spotted before morning twilight as the shower approaches. Viewers in Asia will fare better since the peak occurs before sunrise there. In any case, one should observe from a clear, dark location with a good horizon. Look high in the northeast for meteors appearing to radiate out of a point between the constellations of Hercules the strong man and Boötes the herdsman. Binoculars or telescopes are not needed to observe meteors. This year Full Moon occurs on New Years Eve which means a waning gibbous moon will interfere with observations of the fainter meteors between midnight and dawn. Incidentally, meteor showers are usually named after the constellation out of which the meteors seem to originate, i.e., their radiant point. However, there is no modern constellation of Quadrans. Instead, this shower retains its name from the obsolete constellation of Quadrans Muralis an instrument used to measure the positions of stars. The actual radiant of the shower is in the edge of Boötes.

(From several sources: 1 dan 2)

Gerhana Bulan di Malam Tahun Baru

Malam tanggal 31 Desember 2009, akan dihiasi dengan adanya fenomena Gerhana Bulan Sebagian. Hanya sedikit piringan Bulan akan memasuki umbra Bumi sehingga permukaan Bulan purnama akan nampak sedikit redup dibandingkan biasanya.

Data lengkap tentang Gerhana Bulan tersebut dapat dilihat di bawah ini (klik untuk gambar dengan resolusi yang lebih besar, note: Jam WIB setara dengan UT + 7 jam dan fenomena gerhana dapat teramati baik setelah mulai masuk fasa U1):

Source: NASA dan Wikipedia

Hujan Meteor Geminid di Penghujung Tahun 2009

Di penghujung tahun 2009, di tengah guyuran hujan yang turun hampir setiap harinya, kita akan mendapat kesempatan untuk menikmati Hujan Meteor Geminid yang merupakan hujan meteor tahunan. Jadi.. siapkan kopi dan coklat panas untuk menemanimu memandangi kilatan meter di malam hari…

Hujan meteor Geminid akan megalami puncaknya pada tanggal 13 – 14 Desember 2009, bertepatan dengan dimulainya Bulan Baru, sehingga ini akan menjadi kesempatan yang baik untuk melakukan pengamatan karena tidak akan ada cahaya bulan. Hujan meteor Geminid akan bisa teramati dari sleuruh wilayah di Indonesia pada tanggal 13 Desember malam menjelang dini hari dan pada tanggal 14 malam menjelang tengah malam. Menurut perkiraan International Meteor Organization, di saat maksimum meteor yang akan terlihat bisa mencapai 100 – 140 meteor per jam, pada tanggal 14 Desember jam 05.10 UT atau jam 12.10 wib.

Hujan meteor Geminid merupakan salah satu hujan meteor yang dinantikan karena intensitasnya yang terus meningkat dalam dekade ini dan diharapkan tren yang sama masih akan diteruskan.

Meteor yang tampak dari rasi Gemini ini berasal dari sisa pecahan obyek yang dikenal sebagai 3200 Phaethon, yang dulunya diperkirakan merupakan asteroid. Saat ini Phaethon sudah menjadi komet yang punah. Jadi sebenarnya, ia adalah kerangka batuan dari komet yang sudah kehilangan es setelah berkali-kali melintas Matahari dari dekat. Nah, Bumi yang melintas dalam aliran puing-puing 3200 Phaethon setiap tahun pada pertengahan Desember akan menyebabkan puing-puing itu terbang dari rasi Gemini/. Tepatnya di dekat bintang terang Castor dan Pollux.

Meteor Geminid pertama kali terlihat pada akhir abad ke-19, tak lama setelah perang sipil di Amerika berakhir. Pada saat pertama muncul, hujan meteornya masih lemah dan tidak terlalu menarik perhatian. Pada saat itu debu yang masuk atmosfer Bumi itu hanya bergerak dengan kecepatan 130000 km/jam. Di masa itu, sama sekali tak nampak kalau hujan meteor ini akan berlangsung setiap tahun. Yang menarik, saat ini hujan meteor Geminid merupakan salah satu hujan meteor yang cukup kuat dan menarik perhatian para pengamat. Bahkan ia semakin kuat dari tahun ke tahun. Hal ini disebabkan oleh gravitasi Jupiter yang berlaku pada aliran puing-puing Phaethon dan menyebabkan mereka bergeser mendekati orbit Bumi. Meteor Geminid sendiri masih tergolong meteor dengan kecepatan menengah pada kisaran 35 km / detik, sehingga akan mudah dikenali di bentangan langit malam.

Jadi, apa yang harus dilakukan untuk mengamati hujan meteor Geminid? Sediakan kopi..atau coklat panas. Keluarlah ke halaman atau area lapang. Bawa peta langit (planisphere/laptop/PDA yang sudah dilengkapi piranti peta langit) untuk dilihat, bawa senter, siapkan ipod, dan mulailah menatap langit ke arah timur laut, dimana rasi Gemini berada. Rasi Gemini akan terbit pada kisaran pukul 21.00 wib, jadi anda bisa keluar rumah mulai jam 21.00 sampai dini hari untuk menikmati hujan meteor Geminid.

Sumber: www.langitselatan.com

2012 Doomsday Hoax

Sudahkah Anda menonton film 2012? Film ini mengisahkan tentang bencana besar yang diperkirakan akan terjadi pada tahun tersebut. Namun, tahukah Anda banyak fake science yang dimasukkan dalam film tersebut? Jadi, Anda tidak perlu khawatir dunia akan segera kiamat karena tidak ada alasan dan bukti kuat tentang ramalan semacam itu. Berikut ini akan ditampilkan sebuah artikel dari universe today, yang menuliskan pendapat NASA tentang isu-isu yang tidak benar yang diperkirakan orang (bahkan dengan bodohnya dipercaya orang) akan terjadi di tahun 2012 (khususnya di tanggal 21 Desember 2012).

NASA is now joining in to combat the 2012 nonsense. Don Yeomans, manager of NASA's Near Earth Object office has produced a video and written an article, providing the scientific realities surrounding the celestial happenings of 2012. Yeomans has done a wonderful job explaining everything that is and isn't going to happen in 2012, and we're happy to add his work to our collection of 2012 debunking articles.

The Galileo spacecraft's view of the Moon and Earth On December 16, 1992, 8 days after its encounter with Earth, the Galileo spacecraft looked back from a distance of about 6.2 million kilometers (3.9 million miles) to capture this remarkable view of the Moon in orbit about Earth. Image credit: NASA/JPL There apparently is a great deal of interest in celestial bodies, and their locations and trajectories at the end of the calendar year 2012. Now, I for one love a good book or movie as much as the next guy. But the stuff flying around through cyberspace, TV and the movies is not based on science. There is even a fake NASA news release out there… So here is the scientific reality on the celestial happenings in the year 2012.

Nibiru, a purported large object headed toward Earth, simply put – does not exist. There is no credible evidence – telescopic or otherwise – for this object's existence. There is also no evidence of any kind for its gravitational affects upon bodies in our solar system.

The Mayan calendar does not end in December 2012. Just as the calendar you have on your kitchen wall does not cease to exist after December 31, the Mayan calendar does not cease to exist on December 21, 2012. This date is the end of the Mayan long-count period, but then – just as your calendar begins again on January 1 – another long-count period begins for the Mayan calendar.

There are no credible predictions for worrisome astronomical events in 2012. The activity of the sun is cyclical with a period of roughly 11 years and the time of the next solar maximumis predicted to occur in the period 2010 – 2012. However, the Earth routinely experiences these periods of increased solar activity – for eons (very long period of time -red) – without worrisome effects. The Earth’s magnetic field, which deflects charged particles from the sun, does reverse polarity on time scales of about 400,000 years but there is no evidence that a reversal, which takes thousands of years to occur, will begin in 2012. Even if this several thousand year-long magnetic field reversal were to begin, that would not affect the Earth’s rotation nor would it affect the direction of the Earth’s rotation axis… only Superman can do that.

The only important gravitational tugs experienced by the Earth are due to the moon and sun. There are no planetary alignments in the next few decades, Earth will not cross the galactic plane in 2012, and even if these alignments were to occur, their effects on the Earth would be negligible. Each December the Earth and Sun align with the approximate center of the Milky Way Galaxy but that is an annual event of no consequence.

The predictions of doomsday or dramatic changes on December 21, 2012 are all false. Incorrect doomsday predictions have taken place several times in each of the past several centuries. Readers should bear in mind what Carl Sagan noted several years ago; "extraordinary claims require extraordinary evidence."

For any claims of disaster or dramatic changes in 2012, the burden of proof is on the people making these claims. Where is the science? Where is the evidence? There is none, and all the passionate, persistent and profitable assertions, whether they are made in books, movies, documentaries or over the Internet, cannot change that simple fact. There is no credible evidence for any of the assertions made in support of unusual events taking place in December 2012.

Written by Don Yeomans, NASA senior research scientist

More on Leonid Meteor Shower 2009

The year 2009 will not see a Leonid storm, but an outburst for sure. There are still some uncertainties regarding the time of maximum of the 1466 trail. For those of you seeking a definitive date and time, it isn't always possible, but we can learn a whole lot about when and where to look.

The Leonid Meteor Shower belongs to the debris shed by comet 55/P Tempel-Tuttle as it passes our Sun in its 33.2 year orbit. Although it was once assumed it would simply be about 33 years between the heaviest "showers," we later came to realize the debris formed a cloud which lagged behind the comet and dispersed irregularly. With each successive pass of Tempel-Tuttle, new filaments of debris are left in space along with the old ones, creating different "streams" the orbiting Earth passes through at varying times, which makes blanket predictions unreliable at best. Each year during November, we pass through the filaments of its debris – both old and new ones – and the chances of impacting a particular stream from any one particular year of Tempel-Tuttle's orbit becomes a matter of mathematical estimates. We know when it passed… We know where it passed. But will we encounter it and to what degree? Traditional dates for the peak of the Leonid meteor shower occur as early as the morning of November 17 and as late as November 19.

So what can we expect this year? According to NASA's 2009 predictions a significant shower is expected this year when Earth crosses the 1466-dust and 1533-dust ejecta of comet 55P/Tempel-Tuttle. According to J. Vaubaillon, the narrow (about 1-hr) shower is expected to peak on November 17, 2009, at 21:43 (1466) and 21:50 (1533) UT, perhaps 0.5 to 1.0 hour later based on a mis-match in 2008, with rates peaking at about ZHR = 115 + 80 = 195/hr (scaled to rates observed in 2008). E. Lyytinen, M. Maslov, D. Moser, and M. Sato all predict similar activity from both trails, combining to about ZHR = 150 – 300 /hr. P. Jenniskens notes that if the calculated trail pattern is slightly shifted in the same manner as observed before, then the 1533-dust trail would move in Earth's path and its rates would be higher (the 1466-dust trail would move away). However, the 1533-dust trail is distorted in the models, and because of that it is not clear how much higher that would be. This remains a rare opportunity to study old dust trails from comet 55P/Tempel-Tuttle. In such old trails, the model of Lyytinen and Nissinen predicts wide trails, which can be tested by measuring the width of the outburst profile.
Let's take a closer look at the at how the two centuries old trails will affect our observing, beginning with the one created in the year 1466. The exact same trail will be encountered again this year with its maximum rate of up to 115 meteors per hour occurring at 21:43 UT (may be 0.5-1hr later). "The trail will be much closer to the Earth, explaining why we expect a quite high zenith hourly rate." say J. Vaubaillon (et al), "However the discrepancy between the expected time of maximum remains, as well as a general higher expected ZHR. Among the possible explanations are: sensitivity to initial conditions (given that the trail is 16 Rev. old) or change of cometary activity (impossible to verify unfortunately)."
But don't count on only this single trail, because the year 1533 trail will encounter the Earth at almost the same time as the 1466 trail. Its maximum time of arrival is expected to be at 21:50 UT on the 17th of November, with a zenith hourly rate of 80 – for a combined rate of perhaps 200 meteors per hour. "The total level of the shower (ZHR~200/hr) was callibrated using the 2008 observations of the 1466 trail, but nothing is known from the 1533 trail. As a consequence, it will be very interesting to check." comments Vaubaillon, "In particular there might be a difference of up to 1 hour between the 1466 and 1533 trail, or they might even be late together, giving us some insight about how well/poorly we know comet 55P's orbit."

Let's take a closer look with 3D-view of the two trails may have evolved between 1466 and 2009.


Dr. Vaubaillon's colleagues from MSFC (D. Moser and B. Cooke) pointed out that the best location to view the outburst caused by the 1466 and 1533 trails will be centered around India and includes: Nepal, Thailand, Western China, Tadjikistan, Afghanistan, Eastern Iran, South Central Russia, etc. Dr. P. Atreya (IMCCE), citizen of Nepal, is currently organizing an international Leonid observation campaign in his home country. This campaign will involve many amateurs and researchers from Nepal and other countries. The climate conditions in Nepal at this time of the year makes it an excellent spot.

We may never know precisely where and when the Leonids might strike, but we do know that a good time to look for this activity is well before dawn on November 17, 18 and 19. Where do you look? For most of us, the best position will be to face east and look overhead.

Source: Universe today

A trivia question:
Can you calculate how thick the meteor cloud based on information given?

Leonid Meteor Shower 2009

Bagi Anda yang tidak sempat menyaksikan Leonid Meteor Shower kemarin, silakan saksikan beberapa video yang berkaitan berikut ini.

The Leonid shower is made of bits of debris from the Tempel-Tuttle comet, which streaks through Earth's inner solar system every 33 years.

It leaves a stream of debris in its wake. Forecasters, however, say it's hard to know exactly how many of the meteors will be visible.

This year's Leonid meteor shower will peak early Tuesday, forecasters say, producing mild but pretty sparks over the United States and a more intense outburst over Asia.

Time lapse sequence between the hours of 4:30 UT and 13:30 UT November 17 (10:30PM-7:30AM CST in Manitoba, Canada) looking towards the zenith in a suburban back yard. There are few meteors visible. Most of the streaks in this movie sequence are airplanes.

Source: youtube

GLOBE at Night 2009 - Can You See the Stars?

Turning out the lights for "Earth Hour" is going to be a great way to demonstrate caring about climate changes by turning off the lights - but what about the impact that light pollution has on our skies? 2008 marked a monumental shift in human history when the number of people living in cities exceeded half the people on Earth. Because of the ambient light of urban landscapes, many city dwellers have never seen a sky full of stars. Are you interested in helping science study the impact of lighting in your area? Then step inside and learn more about GLOBE…

GLOBE at Night is a wonderful way for everyone around the world to participate as a citizen-sciencist to raise public awareness of the impact of artificial lighting on local environments. This event encourages everyone - students, educators, dark sky advocates and the general public - to measure the darkness of their local skies and contribute their observations online to a world map. GLOBE at Night is a centerpiece of the Dark Skies Awareness Global Cornerstone Project for the International Year of Astronomy (IYA) in 2009, and we need people - just like you - to get involved! Data collection and online reporting is simple and user-friendly.

Led by the educational outreach staff at the National Optical Astronomy Observatory and the University Corporation for Atmospheric Research GLOBE Program, the GLOBE at Night campaign will take place for a 4th year from March 16-28, 2009. “The geographic reach of the GLOBE at Night program exceeded our wildest expectations,” said Connie Walker, an astronomer and science education specialist at the National Optical Astronomy Observatory (NOAO), one of the event’s major co-sponsors. “We fell a few hundred short of our target of 5,000 total observations, but the engagement and excitement of large family groups, and dozens of school children participating in the activity together, more than make up for a few less data points.”

Over the past 3 years, tens of thousands of citizen-scientists around the world have contributed measurements of their local sky brightness to a growing global database in two ways: simple unaided-eye observations toward the constellation Orion and quantative digital measurements through a handheld, well-calibrated sky-brightness meter. For the first method, citizen-scientists take data on light pollution levels by comparing what they see toward Orion, with star maps showing different stellar brightness limits. The basic idea is to look for the faintest stars and match them to one of seven star maps of progressively fainter limiting magnitudes. For the second method, digital sky-brightness meters are used for more precise measurements. The low-cost digital Sky Quality Meters (SQMs), manufactured by Unihedron, can make a highly repeatable, direct measurement of integrated sky brightness. The newly available second-generation of SQM-Ls being used this year by several GLOBE at Night sites has a cone-shaped “field of view” that is three times more narrow than the older model. This specifically aids its use in city environments, where surrounding lights or buildings may affect the readings.

To learn the five easy steps to participate in either type of GLOBE at Night program and to obtain important information on light pollution, stellar magnitudes, the mythology of Orion, how to find Orion, how to obtain your latitude and longitude, and how to use an SQM, see the GLOBE at Night website. No prior experience is necessary and all the information you need to participate is right there - along with downloads for activity kits for families, teachers and invididuals in six different languages. All observations will be available online via Google Earth and as downloadable datasets, too.


Thanks to an international network of partners, GLOBE reaches people around the world, and during their first two years managed 20,000 observations from a total of 100 countries. This year, they're hoping for an even greater success rate and within weeks of submitting your data, a world map showing the results of your studies will be made available. Using this information, you can then compare the data to previous studies, as well as satellite data and population density data. Collecting information from mulitple locations inside a single city or region is highly encourged, and would make a great class project or astronomy club activity!

By activity participating in projects like GLOBE, you can make difference. More measurements made each year and over the next few years will allow for in more depth analysis. More measurements within a city will provide maps of higher resolution and comparisons between years would allow people to monitor changes. Just like our other Earthly environments, monitoring our lighting environment will allow us as citizen-scientists to identify and preserve dark sky locations in cities or catch an area developing too quickly and influence people to make smart choices in lighting by providing them with informed neighbors. As just everyday, ordinary people, we can impact what happens by educating ourselves and others. If more and more people took a few minutes during the March 2009 campaign to measure sky brightness either toward Orion with the unaided-eye or toward zenith with a Sky Quality Meter (or both!), their measurements - and yours - will make a world of difference!

Cited from : Universe Today - Tammy Plotner

Dokumentasi Gerhana Matahari Cincin 26 Januari 2009

Annular Eclipse on Jan. 26. Credit: M.R. Taufik

Di bawah ini disajikan 4 rekaman video gerhana matahari cincin yang diamati dari Jakarta dan Lampung.

• Video 1 diamati oleh Langit Selatan di Lampung
  

• Video 2 direkam oleh saudara M. Thariq Ziyad, siswa kelas 7 Labschool Kebayoran Jakarta

• Video 3 diperoleh dari alamat ini.

• Keterangan:
• Jakarta, 26 January 2009
• Titik Observasi: Pancoran 12770
• Elevasi: 63 derajat. Arah Barat.
• Waktu: 16.36 pm WIB
• Fase: cincin utuh.

• Video 4 diperoleh dari alamat ini.

Semoga rekaman peristiwa gerhana yang termasuk langka ini bisa disaksikan oleh Anda yang mungkin belum berkesempatan mengamati gerhana tersebut secara langsung (dengan bantuan alat pelindung mata tentunya).

Gerhana Matahari Cincin 26 Januari 2009

Setelah melihat ada artikel baru di Langit Selatan tentang GMC tanggal 26 Januari 2009, Saya baru ingat bahwa waktunya sudah cukup dekat. Oleh sebab itu, di dalam artikel ini akan coba dibahas lebih dalam seluk beluk tentang gerhana Matahari cincin.

Overview
Gerhana Matahari Cincin (Annular Solar Eclipse) adalah peristiwa terhalangnya piringan Matahari oleh piringan Bulan, namun karena Bulan saat itu ada di apogee (jarak terjauhnya dari Bumi) sehingga piringan Bulan sedikit lebih kecil dibandingkan dengan piringan Matahari. Alhasil, piringan Matahari tertutup Bulan tetapi bagian tepinya tidak tertutup dan nampak seperti cincin. Untuk lebih jelasnya, perhatikan ilustrasi di bawah ini:

Sumber : en.wikipedia.org

Simulasi Gerhana Matahari Cincin (GMC) dapat Anda lihat di bawah ini (sumber : www.astrodeneb.org):

Penduduk bumi yang ada di daerah B saja yang pada tanggal 26 Januari nanti bisa mengamati GMC, sisanya (di daerah C) hanya bisa mengamati GM sebagian. Di luar kedua daerah tersebut, tidak akan teramati gerhana apapun. Pada momen GMC 26 Januari 2009 ini, bayang-bayang utama (umbra) Bulan yang jatuh di permukaan Bumi hanya selebar 280 km, sehingga tidak seluruh tempat berkesempatan untuk menyaksikan fase cincin. Momen puncak gerhana sendiri hanya berlangsung kurang dari 8 menit.

Lintasan Gerhana
Gerhana Matahari pertama di tahun 2009 ini terjadi saat Bulan ada di titik simpul naiknya (ascending node) di daerah rasi Capricornus. Gerhana ini termasuk dalam rangkaian gerhana Saros 131. Gerhana Matahari Cincin akan dapat teramati pada daerah yang cukup luas, melewati Samudera Hindia dan bagian barat Indonesia. Gerhana Matahari Sebagian akan dapat diamati dari daerah yang lebih luas, mencakup bagian selatan Afrika, Madagaskar, Australia kecuali daerah Tasmania, tenggara India, Asia tenggara dan Indonesia.

Pada gambar di atas ini, kedua garis biru masing-masing menandai batas paling utara ("atas") dan paling selatan ("bawah") untuk dapat menyaksikan fase cincin GMC. Garis merah adalah jejak greatest eclipse, yaitu momen yang berlangsung ketika jarak sumbu bayang-bayang Bulan dengan pusat Bumi mencapai maksimum. Animasi di bawah ini menunjukkan daerah mana saja yang dapat mengamati gerhana tersebut (sumber: NASA).

Di Indonesia sendiri, daerah yang dilalui lintasan gerhana Matahari cincin ini akan melintasi bagian selatan pulau Sumatera (Lampung dan sekitarnya), bagian barat pulau Jawa (Cilegon, Serang, Anyer, dan sekitarnya) dan bagian tengah pulau Kalimantan. Sedangkan pengamat di wilayah Indonesia lainnya hanya bisa menyaksikan gerhana Matahari sebagian.

Peristiwa GMC 26 Januari 2009
Proses GMC itu akan diawali dengan tertutupnya piringan Matahari oleh Bulan pada pukul 15.21 WIB. Kemudian Matahari akan berubah menjadi bentuk sabit hingga akhirnya seluruh piringan Bulan sudah berada di dalam piringan Matahari. Inilah yang disebut dengan puncak GMC, yang akan terjadi pada pukul 16.40 WIB. Kita akan melihat Matahari berbentuk cincin selama sekitar 6 menit. Setelah itu Bulan mulai keluar dari piringan Matahari hingga pada pukul 17.52 WIB Bulan sudah benar-benar meninggalkan piringan Matahari sebagai tanda bahwa peristiwa GMC ini sudah berakhir. Jadi dari perhitungan di atas, berarti waktu yang kita miliki untuk melihat Bulan menutupi Matahari adalah sekitar 90 menit.

Di Tanjung Karang (Lampung), fase cincin dimulai pukul 16.38 WIB, puncak gerhana 16.41 WIB, dan fase cincin berakhir pada pukul 16.44 WIB.Si Samarinda (Kaltim), fase cincin dimulai pukul 17.48 WITA, puncak gerhana 17.49 WITA, dan fase cincin berakhir pada pukul 17.50 WITA.Sebagian kecil daratan di Sulawesi juga dilintasi bayang-bayang Bulan. Di Manado, awal gerhana (kontak I) dimulai pukul 16.42 WITA, momen puncak gerhana 17.49 WITA, dan akhir gerhana (kontak 4) pada pukul 18.50 WITA.

Untuk simulasi GMC ini dari berbagai daerah, silakan dilihat di sini.

Pengamatan Gerhana
Untuk mengamati gerhana ini, ada beberapa hal yang harus Anda perhatikan:

1. Safety Procedures.
Mengamati gerhana Matahari dengan cara yang salah (tanpa pelindung, baik dengan mata langsung maupun dengan menggunakan binokular, teropong, teleskop tak berpelindung) dapat mengakibatkan KEBUTAAN PERMANEN. Hal ini disebabkan pada saat kita mengamati piringan Matahari (meskipun sudah tertutup sebagian) tetap memancarkan energi yang besar yang dapat mengurangi kepekaan mata bahkan membakar retina kita!. Tapi, tentunya hal ini jangan membuat Anda menjadi paranoid atau takut untuk mengamati gerhana.

Cara yang aman untuk mengamati Gerhana Matahari antara lain dengan :
a. Kamera lobang jarum.


b. Filter Matahari
Filter ini umumnya sering digunakan untuk mengamati gerhana matahari dengan alat pengamatan seperti teleskop.

Filter Matahari ini juga ada yang dapat dipakai untuk pengamatan langsung.

Anda juga dapat membuat filter Matahari ini sendiri. Lihat penjelasannya di sini.

c. Mengamati gerhana lewat proyeksinya. Cara ini juga murah dan sederhana untuk dilakukan jika kita mempunyai dan ingin menggunakan alat bantu optik (misalnya teleskop) untuk mengamati gerhana. Anda dapat meletakkan selembar kertas putih di belakang teleskop untuk menangkap proyeksi peristiwa gerhana tersebut.

Source : ESO

Safety procedures lainnya dapat di sini.

Sekali lagi diingatkan :

JANGAN SEKALIPUN MENGAMATI MATAHARI TANPA FILTER PENAPIS CAHAYA MATAHARI, BAIK MEMAKAI MATA TELANJANG, (apalagi) TELESKOP, ATAU ALAT BANTU OPTIK LAINNYA, KARENA AKAN MERUSAK DAN BAHKAN MEMBUTAKAN MATA ANDA SECARA PERMANEN.

2. Lokasi pengamatan
Seperti yang sudah dijelaskan di atas, GMC ini hanya bisa diamati dari daerah-daerah tertentu saja. Jika Anda tidak tinggal di daerah yang dilewati lintasan umbra Bulan, maka Anda harus melakukan perjalanan luar kota. Hal yang perlu diperhatikan adalah transportasi dan akomodasi Anda selama di sana.

3. Cuaca
Kita tidak bisa memastikan bahwa cuaca pada hari-H akan cerah. Oleh karena itu kita harus mempersiapkan diri jika terjadi hujan besar saat itu. Peralatan yang kita bawa harus bebas dari resiko basah terkena hujan. Anda dapat melengkapi bawaan dengan sejumlah tas plastik besar (trash bag) sebagai antisipasi darurat kala hujan turun tiba-tiba.

(diadaptasi dari : Langit Selatan (dan Weblog Astronomi Berbahasa Indonesia), Wikipedia, NASA, Bosscha)

International Year of Astronomy 2009

The International Astronomical Union (IAU) launched 2009 as the International Year of Astronomy (IYA2009) under the theme, The Universe, Yours to Discover. IYA2009 marks the 400th anniversary of the first astronomical observation through a telescope by Galileo Galilei. It will be a global celebration of astronomy and its contributions to society and culture, with a strong emphasis on education, public engagement and the involvement of young people, with events at national, regional and global levels throughout the whole of 2009. UNESCO has endorsed the IYA2009 and the United Nations proclaimed the year 2009 as the International Year of Astronomy on 20 December 2007.

The vision of the International Year of Astronomy (IYA2009) is to help the citizens of the world rediscover their place in the Universe through the day- and night time sky, and thereby engage a personal sense of wonder and discovery. All humans should realize the impact of astronomy and basic sciences on our daily lives, and understand better how scientific knowledge can contribute to a more equitable and peaceful society.

Astronomy is one of the oldest fundamental sciences. It continues to make a profound impact on our culture and is a powerful expression of the human intellect. Huge progress has been made in the last few decades. One hundred years ago we barely knew of the existence of our own Milky Way. Today we know that many billions of galaxies make up our Universe and that it originated approximately 13.7 billion years ago. One hundred years ago we had no means of knowing whether there were other solar systems in the Universe. Today we know of more than 200 planets around other stars in our galaxy and we are moving towards an understanding of how life might have first appeared. One hundred years ago we studied the sky using only optical telescopes and photographic plates. Today we observe the Universe from Earth and from space, from radio waves to gamma rays, using cutting edge technology. Media and public interest in astronomy have never been higher and major discoveries are frontpage news throughout the world. The IYA2009 will meet public demand for both information and involvement.

There are outstanding opportunities for everyone to participate in the IAU IYA2009 events. This brochure outlines some of the events planned at the global level, which will be supported by thousands of additional national and regional activities.

The IAU, UNESCO and our Organisational Associates wish everyone a year rich in astronomical experiences as we all celebrate the International Year of Astronomy 2009!

For resources in the form of powerpoint and PDF, click on the following links.

1. Powerpoint slides
• The International Year of Astronomy 2009
• The International Year of Astronomy 2009 - An overview
• What is astronomy?
• Who actually invented the astronomical telescope?
2. PDF Version (Not the original version, this is more compressed versions)
• The International Year of Astronomy 2009
• What is astronomy?
• Who actually invented the astronomical telescope?

This video below is the official trailer for the IYA 2009

Source : www.astronomy2009.org

International Olympiad on Astronomy and Astrophysics 2

Jika sesuai dengan rencana, besok (Selasa,19 Agustus 2008), peserta IOAA kedua dari berbagai negara akan sampai di Bandara Internasional Soekarno-Hatta, Jakarta.

Keesokkan harinya, akan ada upacara pembukaan di SABUGA ITB, Bandung. Tes Teori-nya akan diadakan pada tanggal Kamis, 21 Agustus 2008 dan untuk tes observasi ada dua kemungkinan tanggal yaitu Jumat, 22 Agustus 2008 dan Sabtu, 23 Agustus 2008. Panitia IOAA menyiapkan dua tanggal untuk mengantisipasi cuaca yang tidak mendukung tes observasi, yang memerlukan cuaca cerah.

Selain olimpiade, ada juga acara expo yang merupakan acara pendukung dari acara IOAA 2 ini. Di sana akan ada pameran dari berbagai pihak yang berhubungan dengan astronomi.

Indonesia sebagai tim tuan rumah mengirimkan dua tim untuk berpartisipasi dalam ajang olimpiade astronomi dan astrofisika tingkat internasional ini. Masing-masing tim terdiri dari 5 orang siswa yang telah melewati tahap seleksi dan pelatihan selama beberapa bulan terakhir.

Semoga acara yang direncakan akan berlangsung hingga tanggal 27 Agustus 2008 ini akan berlangsung dengan lancar. Hal ini akan memberikan bukti juga kepada tim dari luar bahwa Indonesia juga mampu mengadakan acara berlevel internasional dengan baik. Untuk tim yang akan bertanding nanti, semoga dapat melakukan yang terbaik dan mampu menunjukkan kepada dunia bahwa ada banyak bibit-bibit cemerlang dalam bidang astronomi dan astrofisika.

Poster Publikasi IOAA 2 (klik untuk versi yang lebih besar):


Jika Anda ingin tahu silabus IOAA tahun ini dan soal IOAA 1, Thailand serta solusinya, silakan dowload dari link yang ada di bawah ini :
* Daftar Tim Pembina IOAA, Materi dan Jadwal Pelatihan, 2008
* Practical Round IOAA 2007, Thailand
+ Observation Part : problem; solution
+ Data Analysis Part :problem; solution
* Theoretical Round IOAA 2007, Thailand : problem: solution

Semoga Anda bisa tambah terinspirasi untuk belajar lebih baik lagi. Siapa tahu tahun depan giliran Anda yang menjadi peserta.

Referensi :
1. Informasi tentang IOAA 2 diambil dari situs resmi IOAA 2
2. Semua soal diambil dari situs resmi IOAA 2007 dan situs Dr.Suryadi Siregar