Banjar Ciamis Pangandaran Tasikmalaya Rukyatul Hilal Community

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Menentukan Tempat Observasi dan Penelitian


Beberapa Pengertian:


Ru’yatul Hilal Ramadhan 1430 H


Pengertian Hilal: Awal Bulan

Ru’yah : Melihat

Hisab : Menghitung

Ijtimak : konjungsi


Terlihatnya hilal bergantung faktor:

1. Kontras antara kecerlangan hilal dgn langit sekitar.

2. Ketebalan hilal, umur hilal.

3. Mata pengamat.

4. Elongasi memadai. Ijtimak / Konjungsi


Awal Ramadhan 1430 H: Kamis n 20 Agustus 2009 Pukul 17:02:48 WIB


Awal Syawal 1430 H: Sabtu 19 September 2009 Pukul 01:45:36 WIB


Garis Ketinggian hilal 0° Awal Ramadhan 1430 H

Visibilitas Hilal 20 Agustus 2009

Visibilitas Hilal 20 Agustus 2009

Visibilitas Hilal 21 Agustus 2009

Visibilitas Hilal 21 Agustus 2009

Garis Ketinggian hilal 0° Awal Syawal 1430 H

Berdasarkan hisab

    Ketika maghrib 20 Agustus 2009 (29 Shaban 1430 H), hilal berada di bawah ufuk.
    Umur <>
    ketinggian: -10 s/d -20
    Bulan Sya’ban digenapkan 30 hari
    1 Ramadhan 1430 H, bertepatan dengan tanggal 22 Agustus 2009.

Berdasarkan hisab

    Ketika maghrib 19 September 2009 (29 Ramadhan 1430 H), hilal berada di atas ufuk.
    Umur > 10 jam
    Ketinggian: 40 s/d 60
    1 Syawal 1430 H, akan bersesuaian dengan tanggal 20 September 2009.

Berdasarkan hisab

Prediksi Awal Bulan Menurut Berbagai Kriteria

    Rukyat Hilal
    Imkanur Rukyat
    Wujudul Hilal
    Rukyat Global (Matla al Badar)

1. Kriteria Ru’yat Hilal (bil Fi'li)

Wajib menggunakan rukyatul hilal bil fi'li, yaitu dengan merukyat hilal secara langsung pada setiap tanggal 29 penanggalan Hijriyah.

Bila tertutup awan atau menurut Hisab hilal di bawah ufuk, tetap merukyat untuk kemudian mengambil keputusan dengan menggenapkan (istikmal) bulan berjalan menjadi 30 hari.

Hisab juga tetap digunakan, namun hanya sebagai alat bantu dan bukan penentu awal bulan Hijriyah.

Jika bulan terlihat maka awal bulan akan jatuh esok harinya.

Jika tidak maka jumlah hari dalam sebulan digenapkan menjadi 30 hari meski menurut metode hisab umur bulan ditetapkan hanya 29 hari.

2. Imkanur Rukyat

Sering disebut juga dengan ijtimak qoblal ghurub, yaitu terjadinya konjungsi (ijtimak) sebelum tenggelamnya matahari.
Konjungsi (ijtimak) telah terjadi sebelum Matahari tenggelam

Bila Bulan tenggelam setelah Matahari, maka keesokan harinya dinyatakan sebagai awal bulan.

Berpuasalah kalian karena melihat hilal dan berbukalah kalian karena melihatnya. Jika ia tertutup awan, maka sempurnakan bilangan syaban menjadi 30 hari. (HR. Bukhari & Muslim)

Berdasarkan pada hadist yang menyatakan: jika satu penduduk negeri melihat bulan, hendaklah mereka semua berpuasa meski yang lain mungkin belum melihatnya.

Memungkinkan posisi hilal yang masih dibawah ufuk, bersamaan dengan tenggelamnya matahari, atau terbenam setelah matahari.

Dipakai oleh sebagian muslim di Indonesia lewat organisasi-organisasi tertentu yang merujuk kepada terlihatnya hilal di negara lain dalam penentuan awal bulan Hijriyah termasuk penentuan awal Ramadhan, Idul Fitri dan Idul Adha.


3. Kriteria Wujudul Hilal

Tarjih Muhammadiyah 1932 menyatakan As-Saumu wa al-Fithru bir ru'yah wa laa man ilaa bil Hisab (berpuasa dan Idul Fitri itu dengan rukyat dan tidak berhalangan dengan hisab)

Muhammadiyah mulai 1969 tidak lagi melakukan Rukyat dan memilih menggunakan Hisab Wujudul Hilal.

Rukyatul hilal adalah pekerjaan yang sangat sulit dan dikarenakan Islam adalah agama yang tidak berpandangan sempit, maka hisab dapat digunakan sebagai penentu awal bulan Hijriyah.

Bukan sekadar untuk memperkirakan hilal mungkin dilihat atau tidak, akan tetapi dijadikan dasar penetapan awal bulan Hijriyah sekaligus jadi bukti bahwa bulan baru sudah masuk atau belum.

Pasca 2002 Persatuan Islam (Persis) mengikuti langkah Muhammadiyah menggunakan Kriteria Wujudul Hilal



4. Rukyat Global (Matla al Badar)

Kurangnya pemahaman terhadap perkembangan dan modernisasi ilmu falak yang dimiliki oleh para perukyat sering menyebabkan terjadinya kesalahan identifikasi hilal.

Sering terjadi klaim terhadap kenampakan hilal oleh seeorang atau kelompok perukyat pada saat hilal masih berada di bawah limit visibilitas.

Tidak hanya di Indonesia bahkan di negara-negara lain kasus ini sering terjadi.

Sudah bukan berita baru lagi bahwa Saudi kerap kali melakukan istbat terhadap laporan rukyat yang kontroversi.

Kesimpulan

Ijtimak awal Ramadhan 1430 terjadi pada hari Kamis tanggal 20 Agustus 2009, 17:02:48 WIB.

Saat maghrib tanggal 22 Agustus 2008, ketinggian Hilal antara -1° sampai -2°.

Bulan telah wujud, berumur <>

Semua kriteria menyimpulkan 1 Ramadhan 1430 pada hari Sabtu 22 September 2009.

Ijtimak awal Syawal 1430 terjadi pada hari Sabtu 19 September 2009, 01:45:36 WIB .

Saat maghrib 19 September 2009 ketinggian Hilal antara 2° sampai 6°.

Bulan sudah wujud, berumur < 8 jam.

Berdasarkan wujudul hilal: Idul Fitri 1430 H pada hari Ahad, 20 September 2009.


Dilema Ru’yah dan Hisab 1

Beberapa negara/ormas berbeda pendapat:

• Satu ru’yah untuk semua negeri

• Satu Ru’yah untuk satu dan negeri yang berdekatan

• Masing-masing negeri memiliki ru’yah

Kata “kalian” pada hadits ru’yah berlaku umum untuk semua orang Islam. Jika ada yang melihat Hilal, jujur, terpercaya dan terbukti, maka persaksian itu harus diterima.

Umat Islam itu satu, karena itu perlu penyeragaman dalam penentuan Hilal.

Insya Allah, pendapat yang paling kuat / mendekati kebenaran juga pendapat yang paling ideal adalah pendapat yang pertama:

Satu ru’yah untuk semua

Dilema Ru’yah dan Hisab 2

Fakta, kebanyakan negeri memilih pendapat ke-3 (sebagian ada yang memilih pendapat ke-2), sehingga masih sering terjadi perbedaan dalam penentuan Hilal.

Ego masing-masing negara/ormas masih terlihat, padahal seharusnya yang terlihat hanyalah rasa persaudaraan sesama muslim dan melepas perbedaan negara/atribut ormas.

Ketika penentuan awal Dzulhijjah, banyak negara-negara yang mengikuti hasil Ru’yah Arab Saudi. Tetapi ketika penentuan awal Ramadhan dan Syawal, masing-masing kukuh berpendapat dengan hasil ru’yah di negerinya masing-masing. Aneh, kan?

Disinilah hisab sebenarnya bisa berperan dengan baik. Dengan ilmu hisab yang semakin dikuasai oleh astronom muslim, ditambah dengan bantuan teknologi astromoni, mereka memakai hisab untuk keperluan umat Muslim di seluruh dunia.

Dilema Ru’yah dan Hisab 3

Jadwal shalat 5 waktu untuk seluruh dunia, dibuat dengan hisab dan dipakai oleh mayoritas muslim di dunia, termasuk di Indonesia.

Jadwal shalat pada awalnya diketahui dengan cara melihat perubahan posisi matahari (dengan kata lain Ru’yah Syamsu/ Melihat matahari), tetapi dengan adanya ilmu hisab, jadwal sholat bisa dibuat untuk seluruh tempat di dunia.

Kenapa hisab jadwal shalat bisa digunakan di seluruh dunia? Karena perhitungan hasil hisab –Insya Allah– sama (setidaknya hanya selisih beberapa menit) dengan hasil melihat langsung posisi matahari.

Dilema Ru’yah dan Hisab 4

Jadwal shalat 5 waktu yang diterima di seluruh dunia dibuat dengan hisab, anehnya ketika ahli hisab (astronom muslim) membuat hisab untuk Hilal Ramadan, Syawal dan Dzulhijjah, banyak negeri muslim yang menolaknya.

Aneh! Aneh! Aneh!

Dalam keseharian hidup mereka memakai hisab (untuk shalat), tetapi ketika menentukan Hilal menolaknya.

Bisa diketahui dengan jelas kapan waktu gerhana bulan atau gerhana matahari, di tempat mana terjadinya, dan sebagainya. Dengan adanya informasi seperti itu, kaum muslimin jadi mengetahui kapan waktu gerhana, dan juga bisa bersiap-siap untuk melakukan shalat gerhana.

Dilema Ru’yah dan Hisab 5

Sebenarnya hisab dan Ru’yah tidak bertentangan, malah sebaliknya hisab bisa menjadi pendukung Ru’yah.

Dengan hisab, bisa ditentukan apakah Hilal kemungkinan besar akan terlihat atau tidak.

Jika ahli hisab mengatakan Ru’yah dapat terlihat di suatu tempat, maka hanya perlu pembuktian dengan Ru’yah, dan biasanya –Insya Allah– memang benar (karena perhitungan hisabnya sudah bagus dan semakin baik).

Jika ahli hisab dan astronom muslim mengatakan dengan ilmu hisab dan astronominya bahwa Hilal kemungkinan tidak akan terlihat, maka tinggal buktikan saja dengan Ru’yah, simpel kan?

Dilema Ru’yah dan Hisab 6

Dengan ilmu hisab, maka Insya Allah persatuan umat Islam di dunia dalam masalah penanggalan tahun hijriyah dapat tercapai lagi.

Tidak akan ada lagi perbedaan waktu shaum, Idul Fitri dan Idul Adha di seluruh dunia. Alangkah indahnya jika hal tersebut bisa terwujudnya.

Jika non muslim bisa bersatu merayakan natal setiap tanggal 25 Desember, kita sebagai muslim lebih berhak untuk bisa bersatu dalam shaum (Ramadhan), Idul Fitri (Syawal), dan Idul Adha (Dzulhijjah).


Alloh menghendaki kemudahan


"Alloh menghendaki kemudahan bagimu, dan tidak menghendaki kesukaran bagimu."

(QS:2:185)


Memasuki bulan yang mulya ini mari kita saling memohon maaf atas segala kesalahan, kealpaan, dan kekurangan yang telah dilakukan. Saling mendo’akan semoga kita dapat menyatukan hati untuk meningkatkan kedekatan pada Alloh SWT.

Tingkatkan amal ibadah kita, tinggalkan perilaku yang tidak sesuai dengan ajaran Islam, untuk menyongsong kehidupan yang kekal di akhirat. Segala puji dan bumi dengan segala isinya,  yang mempergilirkan siang dan malam, yang menghamparkan Bumi dan meninggikan langit tanpa tiang, yang menghidupkan dan mematikan, yang senantiasa memenuhi segala kebutuhan. Tidak ada kebahagiaan hakiki kecuali dengan melaksanakan ketaatan kepada-Nya. Tidak ada rasa cukup, kecuali dengan mengharap rahmat-Nya. Tidak ada kemuliaan, kecuali dengan tunduk kepada keagungan-Nya. Tidak ada kehidupan, kecuali dengan keridhaan-Nya. Bagi Alloh, yang menciptakan serta memelihara langit


Satu kali orbit Bumi keliling Surya bukan 360 derajat tetapi 345 derajat dilaluinya selama 354 hari 8 jam 48 menit dan 36 detik. Dalam satu bulan Qamariah, Bumi bergerak sejauh 28˚ 45’ atau dalam satu hari sejauh 0derajat 58’ 28’’,4.


Perlu dicatat bahwa Bulan mengorbit keliling Bumi sejauh 331˚ 15’, selama 29 hari 12 jam 44,04 menit. Dia bergerak dalam satu hari sejauh 11˚ 12’. Jadi keliling 360˚ - 331˚ 15’ = 28˚ 45’ kalau dikalikan 12 bulan Qamariah maka satu tahun Islam adalah 354 hari 8 jam 48 menit dan 36 detik atau 345 derajat gerak edar Bumi keliling Surya.


Untuk mengitari Surya 360 derajat keliling, maka Bumi memakai waktu selama 370 hari. Dalam pada itu satu tahun musim pada abad 20 Masehi dijalani Bumi sejauh 355˚ 12’ selama 365 hari 6 jam. Hal ini dapat dibuktikan dengan terlambatnya bintang-bintang di angkasa pada waktu tertentu yang sama setiap tahunnya sejauh 4˚ 48’.


Sumber:

Pendidikan Fisika FPMIPA Universitas Pendidikan Indonesia

Bpk. Taufik Ramlan R. dan Bpk. Judhistira Aria Utama

Observatorium Bosscha, FMIPA–ITB, Lembang – Jawa Barat
Bpk. Dr. B. Dermawan, Dr. N. Sopwan, Dr. M. Raharto


Semoga Bermanfaat dan Terima Kasih

Arip Nurahman,

Pendidikan Fisika, FPMIPA. Universitas Pendidikan Indonesia

dan

Follower Open Course Ware at MIT-Harvard University, Cambridge. USA.

Nobel Fisika Indonesia

Central for Research and Development for Winning

Nobel Prize in Physics at Indonesia

Nobel Fisika Indonesia

(Belajar Kepada Profesor Onnes)

"for his investigations on the properties of matter at low temperatures which led, inter alia, to the production of liquid helium"

"Untuk pemeriksaannya pada sifat zat pada temperatur rendah yang menunjukkan, inter alia, pada pembuatan helium cair"

H. Kamerlingh Onnes
Born	Heike Kamerlingh Onnes 21 September 1853(1853-09-21) Groningen, Netherlands
Died	21 February 1926(1926-02-21) (aged 72) Leiden, Netherlands
Nationality	Netherlands
Fields	Physics
Institutions	University of Leiden
Alma mater	Heidelberg University University of Groningen
Doctoral advisor	Rudolf Adriaan Mees
Other academic advisors	Robert Bunsen Gustav Kirchhoff Johannes Bosscha
Doctoral students	Jacob Clay Claude Crommelin Wander de Haas Gilles Holst Johannes Kuenen Remmelt Sissingh Ewoud van Everdingen Jules Verschaffelt Pieter Zeeman
Known for	Onnes-effect, Superconductivity
Notable awards	Nobel Prize in Physics (1913)

Heike Kamerlingh Onnes (21 September 1853 – 21 February 1926) was a Dutch physicist and Nobel laureate. He pioneered refrigeration techniques, and he explored how materials behaved when cooled to nearly absolute zero. He was the first to liquify helium. His production of extreme cryogenic temperatures led to his discovery of superconductivity in 1911: for certain materials, electrical resistance abruptly vanishes at very low temperatures.

Photos: Copyright © The Nobel Foundation

Heike Kamerlingh Onnes (lahir di Groningen, Belanda, 21 September 1853 – meninggal di Leiden, Belanda, 21 Februari 1926 pada umur 72 tahun) adalah seorang fisikawan Belanda. Karier ilmiah Onnes dihabiskan menjelajah teknik pendinginan dan fenomena terkait.

Tahun-tahun awal

Ia adalah anak industriwan berada yang darinya ia mewarisi kecenderungan mekanis. Ia mewarisi studi prasarjana dalam fisika dan matematika di Universitas Groningen, rumah asalnya. Sebelum memulai karya sarjananya di kota itu pada 1873, ia menghabiskan 3 semester dengan fisikawan Robert Bunsen dan Gustav Kirchhoff di Heidelberg, Jerman. Dari saat itu ia telah memenangkan beberapa hadiah kompetitif. Pada 1879, ia mendapatkan gelar doktor dalam fisika magna cum laude dengan Prof. R.A. Mees di Groningen. Pada 1878, ia diangkat sebagai asisten Johannes Bosscha, Guru Besar Fisika di Sekolah Politeknik Delft. Pada 1881, ia menerbitkan sebuah karya, Algemene Theorie der Vloeistoffen (Teori Umum Cairan), yang menunjukkan hukum keadaan yang berkenaan dapat diturunkan dari uraian tertimbang, berdasarkan pada sifat dan gerakan molekul.

Jabatan profesor

Kamerlingh Onnes diangkat sebagai guru besar di Universitas Leiden pada 1882. Ia mengetuai Bagian Fisika Eksperimental hingga 1923. Dari awal, tujuannya ialah melanjutkan pengetahuan ilmiah dengan eksperimen yang hati-hati. “Door meten tot weten” [Dari mengukur ke ilmu] ialah mottonya. Ia mendirikan sekolah terkenal buat pembuat alat, yang akan menjamin pasokan perajin terlatih yang cukup ke laboratoriumnya sendiri dan lembaga lain di Belanda selama beberapa dasawarsa. Kamerlingh Onnes menerbitkan sebagian besar karyanya di Verslagen, kemudian Proceedings, dari Akademi Sains dan Ilmiah Kerajaan Belanda (KNAW). Namun, dari awal masa jabatan profesornya di Leiden, ia menerbitkan versi semua karya bahasa Inggrisnya dalam Komunikasi Laboratorium Fisika di Universitas Leiden.

Superkonduktivitas

Kamerlingh Onnes mendirikan laboratorium kelas menengah, yang dilengkapi karya kriogenik yang terkait pada liquifaksi gas. 42 tahun di universitas itu terisi dengan penemuan-penemuan luar biasa. Pencapaian puncaknya ialah liquifaksi helium pada 1908, yang membuka bidang baru fisika temperatur rendah dan memungkinkannya menemukan superkonduktivitas pada 1911. Namun, dari 1880-an hingga 1908 ia dan kelompoknya juga membuat studi meluas perilaku campuran fluida, topik yang terliputi di sini.

The Nobel Prize in Physics 1913

Heike Kamerlingh Onnes

The Nobel Prize in Physics 1913

• Summary
• Presentation Speech

Heike Kamerlingh Onnes

• Biographical
• Nobel Lecture

• Banquet Speech

Presentation Speech

Presentation Speech by former Councillor Th. Nordstrom, President of the Royal Swedish Academy of Sciences, on December 10, 1913

Your Majesty, Your Royal Highnesses, Ladies and Gentlemen.

At its meeting on the 11th November the Royal Academy of Sciences decided to award the Nobel Prize for Physics for the year 1913 to Dr. Heike Kamerlingh Onnes, Professor at the University of Leyden "for his investigations on the properties of matter at low temperatures which led, inter alia, to the production of liquid helium".

As early as 100 years ago research into the behaviour of gases at various pressures and temperatures gave a great impetus to physics. Since this time the study of the connection between the pressure, the volume and the temperature of gases has played a very important part in physics, and particularly in thermodynamics - one of the most important disciplines of modern physics.

In the years 1873 and 1880 Van der Waals presented his famous laws governing gases which, owing to their great importance for thermodynamics, were rewarded by the Royal Academy of Sciences in 1910 with the Nobel Prize for Physics.

The thermodynamic laws of Van der Waals were laid down on atheoretical basis under the assumption that certain properties could be attributed to molecules and molecular forces. In the case of gases the properties of which are changed by pressure and temperature, or in one way or another do not agree with Van der Waals' hypothesis, deviations from these laws occur.

A systematic experimental study of these deviations and the changes they undergo due to temperature and the molecular structure of the gas must therefore contribute greatly to our knowledge of the properties of the molecules and of the phenomena associated with them.

It was for this research that Kamerlingh Onnes set up his famous laboratory at the beginning of the 1880's, and in it he designed and improved, with unusual success, the physical apparatus needed for his experiments.

It is impossible to report briefly here on the many important results of this work. They embrace the thermodynamic properties at low temperatures of a series of monatomic and diatomic gases and their mixtures, and have contributed to the development of modern thermodynamics and to an elucidation of those associated phenomena which are so difficult to explain. They have also made very important contributions to our knowledge of the structure of matter and of phenomena related to it.

Whilst important on its own account, this research has gained greater significance because it has led to the attainment of the lowest temperatures so far reached. These lie in the vicinity of so-called absolute zero, the lowest temperature in thermodynamics.

The attainment of low temperatures in general was not possible until we learnt to condense the so-called permanent gases, which, since Faraday's pioneer work in this field in the middle of the 1820's, has been one of the most important tasks of thermodynamics.

After Olszewski, Linde, and Hampson had prepared liquid oxygen and air in a variety of ways, and after Dewar, having overcome great experimental difficulties, had succeeded in condensing hydrogen, all temperatures down to -259°C, i.e. all temperatures down to 14° from absolute zero, could be attained.

At these low temperatures all known gases can easily be condensed, except for helium, which was discovered in the atmosphere in the year 1895.

Thus, by condensing this it would be possible to reach still lower temperatures. After both Olszewski and Dewar, Travers, and Jacquerod had tried in vain to prepare liquid helium, using a variety of met hods it was generally assumed that it was impossible.

The question was solved in 1908, however, by Kamerlingh Onnes, who then prepared liquid helium for the first time.

I should have to cover too much ground if I were to report here on the experimental equipment with which Kamerlingh Onnes was at last successful in liquefying helium, and on the enormous experimental difficulties which had to be overcome. I would only mention here that the liquefaction of helium represented a continuation of the long series of investigations into the properties of gases and liquids at low temperatures which Kamerlingh Onnes has carried out in so praiseworthy a manner. These investigations finally led to the determination of the so-called isotherms of helium and the knowledge gained here was the first step towards the liquefaction of helium. Kamerlingh Onnes has constructed cold baths with liquid helium which permit research to be done into the properties of substances at temperatures which lie between 4,3° and 1,15° from absolute zero.

The attainment of these low temperatures is of the greatest importance to physics research, for at these temperatures both the properties of the substances and also the course followed by physical phenomena, are generally quite different from those at our normal and higher temperatures, and a knowledge of these changes is of fundamental importance in answering many of the questions of modern physics.

Let me mention one of these particularly here.

Various principles borrowed from gas thermodynamics have been transferred to the so-called theory of electrons, which is the guiding principle in physics in explaining all electrical, magnetic, optical, and many heat phenomena.

The laws which have been arrived at in this way also seem to be confirmed by measurements at our normal and higher temperatures. That the situation is at very low temperatures not the same, however, has, amongst other things, been shown by Kamerlingh Onnes' experiments on resistance to electrical conduction at helium temperatures and by the determinations which Nernst and his students have carried out in relation to specific heat at liquid temperatures.

It has become more and more clear that a change in the whole theory of electrons is necessary. Theoretical work in this direction has already been begun by a number of research workers, particularly by Planck and Einstein.

In the meantime new supports had to be created for these investigations. These could only be obtained by a continued experimental study of the properties of substances at low temperatures, particularly at helium temperatures, which are the most suitable for throwing light upon phenomena in the world of electrons. Kamerlingh Onnes' merit lies in the fact that he has created these possibilities and at the same time opened up a field of the greatest consequence and significance to physical science.

Owing to the great importance which Kamerlingh Onnes' work has been seen to have for research in physics, the Royal Academy of Sciences has found ample grounds for bestowing upon him the Nobel Prize for Physics for the year 1913.

From Nobel Lectures, Physics 1901-1921, Elsevier Publishing Company, Amsterdam, 1967

Copyright © The Nobel Foundation 1913

Sumber:

1. Wikipedia

2. Nobel Prize Org.

Ucapan Terima Kasih:

1. DEPDIKNAS Republik Indonesia

2. Kementrian Riset dan Teknologi Indonesia

3. Lembaga Ilmu Pengetahuan Indonesia (LIPI)

4. Akademi Ilmu Pengetahuan Indonesia

5. Tim Olimpiade Fisika Indonesia

Disusun Ulang Oleh: 

Arip Nurahman

Pendidikan Fisika, FPMIPA, Universitas Pendidikan Indonesia
&
Follower Open Course Ware at MIT-Harvard University, USA.

Semoga Bermanfaat dan Terima Kasih

Nobel Fisika Indonesia

NCentral for Research and Development for Winning

Nobel Prize in Physics at Indonesia

Nobel Fisika Indonesia

(Belajar Kepada Profesor Nils Gustaf Dalén)

The Nobel Prize in Physics 1912

"for his invention of automatic regulators for use in conjunction with gas accumulators for illuminating lighthouses and buoys"

.

Gustaf Dalén
Born	Nils Gustaf Dalén 30 November 1869(1869-11-30) Stenstorp, Västergötland, Sweden
Died	9 December 1937(1937-12-09) (aged 68) Lidingö, Stockholm, Sweden
Nationality	Swedish
Fields	Physics, mechnical engineering
Institutions	AGA
Alma mater	Chalmers University of Technology, Polytechnikum, Zürich
Known for	Sun valve and other lighthouse regulators
Notable awards	Nobel Prize in Physics (1912)

Nils Gustaf Dalén (30 November 1869 – 9 December 1937) was a Swedish Nobel Laureate and industrialist, the founder of the AGA company and inventor of the AGA cooker and the Dalén light. In 1912 he was awarded the Nobel Prize in Physics for his "invention of automatic regulators for use in conjunction with gas accumulators for illuminating lighthouses and buoys".

Nils Gustaf Dalén (lahir 30 November 1869 di Stenstorp, meninggal 9 Desember 1937) adalah penemu berkebangsaan Swedia, pendiri Svenska Aktiebolaget Gasaccumulator. Ia dianugerahi Nobel Fisika 1912 untuk "penemuan alat atur otomatisnya untuk penggunaan bersama dengan akumulator gas untuk memperjelas mercusuar dan pelampung".

Dalén menemukan Agamassan (Aga), sebuah substrat yang digunakan untuk menyerap gas yang memungkinkan penyimpanan yang aman dan eksploitas komersil. Pada awal 1912, Dalén menjadi buta dalam sebuah ledakan asetilen. Di tahun yang sama ia dianugerahi Hadiah Nobel. Dalén terlalu sakit untuk menghadiri penganugerahan itu sehingga saudaranya, seorang dokter mata, Profesor Albin Dalén, dari Karolinska Institutet duduk di tempatnya. Walau buta, Dalén tetap memimpin AGA hingga 1937.

The Nobel Prize in Physics 1912

Gustaf Dalén

The Nobel Prize in Physics 1912

• Summary
• Presentation Speech

Gustaf Dalén

• Biographical
• Nobel Lecture

• Banquet Speech
• Documentary
• Other Resources

Presentation Speech

Presentation Speech by Professor H.G. Söderbaum, President of the Royal Swedish Academy of Sciences, on December 10, 1912

Your Majesty, Your Royal Highnesses, Ladies and Gentlemen.

The Royal Academy of Sciences believes it is acting in strict accordance with Alfred Nobel's will in awarding the Physics Prize to Chief Engineer Gustaf Dalén in recognition of his remarkable invention of automatic valves designed to be used in combination with gas accumulators in lighthouses and light-buoys.

The ever-growing use of maritime communication creates an increased demand for navigational safety devices. Amongst these devices lighthouses and light-buoys are of great importance, and their number has become several times greater during the last few decades. At the same time efforts have been made to find ways of making their lights more powerful and their different lights more easily distinguishable. As far as possible, work has been directed towards finding a system which would regulate these lights automatically. This is a very important point, for no country is wealthy enough to maintain a continuous inspection of all its necessary lighting equipment.

In Sweden, a country with a long coastline and large archipelagos, the problem of a reliable and fairly inexpensive lighting organisation has for a long time been more pressing than elsewhere.

About 1895, for the first time it was discovered how to prepare acetylene from calcium carbide on a commercial scale. Acetylene is a gaseous hydrocarbon which, when burnt, produces an extremely bright and white light.

The first attempt to use this gas for lighting in lighthouses did not have very satisfactory results. The petroleum gas in use for similar purposes up to this time had been compressed and enclosed in large iron containers. It was found extremely dangerous to treat acetylene in the same manner, as this gas, when under the pressure of one or more atmospheres, explodes at the slightest shock. It was also attempted to store calcium carbide in lightbuoys and to let the acetylene escape under the action of water supplied automatically. Unfortunately this method proved to be inconvenient, not very reliable, and unusable in cold weather.

In 1896, two French chemists, Claude and Hess, discovered that acetone possesses the property of dissolving large quantities of acetylene. This solution is not explosive. However, it cannot be used as it is to store acetylene, because, even if the container is filled to the brim with a saturated solution under high pressure, the volume of the liquid is reduced by consumption or by cooling, and explosive acetylene gas is produced in the space above the surface of the liquid.

It was then discovered that its explosive nature disappears if the acetylene solution is compressed in a porous mass. Numerous unsuccessful attempts were made to prepare such a porous mass which would be sufficiently resistant and elastic to withstand the shocks encountered in transportation, without cracking and crumbling and thus producing cavities filled with explosive acetylene gas.

The credit for the eventual discovery of such a mass, called aga or porous substance, belongs to Gustaf Dalén.

By a complicated and carefully developed process, this substance is enclosed in steel containers which thus become practical accumulators for the acetylene gas. The porous mass in the container is half-filled with acetone, and acetylene is then introduced by compressing it to a pressure of ten atmospheres. Under this pressure, and at a temperature of 15° C, the container contains one hundred times its own volume of acetylene. The container is then ready for supplying to a lighthouse or light-buoy the acetylene necessary for lighting.

The advantage of this arrangement would not be great if the acetylene light had to burn uninterruptedly. On the one hand, this form of lighting would be quite costly, and, on the other hand, it would be difficult to distinguish the lights of various lighthouses from one another and from other lightsources. True, several methods of producing an intermittent light were already known. For example, the flame can be surrounded by moving screens, or the lighting device itself can be made to rotate. But such arrangements need continual inspection and consequently involve considerable expense.

Where compressed petroleum gas was used as the source of light, eclipsing or flashing lighting devices had also been constructed using the escaping gas as motive power. The flashes lasted 5 to 7 seconds, which was perhaps necessary because of the weak light output of petroleum gas. But with the intense brightness of acetylene light, such a long flash becomes unnecessary. Furthermore, long flashes offer insufficient variation of the signal. Accordingly the big lighthouses have generally replaced them with lights giving flashes lasting from 1/10 to 3/10 of a second.

It was about 1904 that Dalén started to study this problem. With a petroleum gas apparatus it was impossible to divide one litre of gas into more than fifty flashes. So Dalén constructed an apparatus, based on an entirely new principle, which by instantaneous opening and closing of the gas pipe, enabled one litre of gas to provide several thousand very rapid but distinct flashes. After a considerable trial period, this ingenious device proved to be extremely reliable. Dalén then provided a brilliant solution for the supplementary problems arising from the use of aga light in the lighthouse service, and an ever increasing number of lighthouses and light-buoys in Sweden have been adapted to this form of lighting. The burner is fitted with a small permanent flame which, in the most usual arrangement, lights a flash every three seconds lasting 3/10 of a second.

In 1907 Dalén crowned his achievement with a further refinement by designing a kind of valve, called the "solar valve", which extinguishes the light at sunrise and relights it when night falls. This valve is controlled by four metal rods enclosed in a glass tube. The lower one is blackened, while the others are gilded and highly polished. Daylight is absorbed by the blackened rod which is heated and consequently expands, closing the gas valve. As the daylight decreases, the black rod reaches the temperature of the other three rods: it contracts and allows the gas valve to reopen.

The device can be regulated in such a way as to act with more or less sensitivity. To be on the safe side, it is usually regulated so that it lights as soon as mist or clouds cover the sun.

The solar valve combined with an intermittent light produces a saving of gas of 93 per cent, and even greater economy might be achieved by prolonging the periods between the flashes.

The use of aga light facilitates the placing of lighthouses and lightbuoys in the most inaccessible places such as archipelagos and seas with dangerous reefs. With the use of one or more of the easily transportable gas accumulators, such lights can give their warning or guiding signals for a whole year or more without the need of inspection or the fear of failure.

The result is an entirely new standard of safety in navigation and an enormous economy. For example, one shoal in Swedish waters previously required a lightship costing approximately 200,000 Kronor and maintained at a cost of about 25,000 Kronor a year. Now, in many cases, navigation is adequately served by establishing an aga buoy with optical and audiosignalling apparatus, the cost of which is 9,000 Kronor, and the annual maintenance of which costs about 60 Kronor.

Most of the maritime nations have now started to install these Dalén devices, and they are to be found operating from Spitzberg, the Varanger Fjord, Iceland and Alaska in the north, to the Straits of Magellan and Kerguelen Island in the south. The annual benefit to navigation can be expressed in terms of saving of thousands of human lives and of hundreds of millions of Kronor.

The aga flame has proved to be extremely useful in other fields, such as the lighting of railway coaches, railway signalling apparatus, car head-lights, soldering, the casting and cutting of metals and so on.

The Academy of Sciences recognizes the true value of all these applications and wishes to emphasize those which contribute to the progress of navigation, because it is uncontestably these that have rendered the greatest benefit to humanity.

The sciences that were especially favoured in the will of the great explosives technician Alfred Nobel, i.e. Physics, Chemistry, and Medicine, have one common feature of involving and sometimes demanding the sacrifice of the experimenter's personal safety. We all know that this year's Physics Prize winner was the victim of a serious accident which prevents him from being here to receive the award from the hands of his King.

He is represented by his brother, Professor Albin Dalén, of the Caroline Institute. Professor, when handing over to your brother the medal and the diploma, I beg you also to convey to him from the Royal Academy of Sciences, our sincere congratulations on the distinction he has merited, and our best wishes for a complete and speedy recovery.

From Nobel Lectures, Physics 1901-1921, Elsevier Publishing Company, Amsterdam, 1967

Copyright © The Nobel Foundation 1912

Sumber:

1. Wikipedia

2. Nobel Prize Org.


Ucapan Terima Kasih:

1. DEPDIKNAS Republik Indonesia

2. Kementrian Riset dan Teknologi Indonesia

3. Lembaga Ilmu Pengetahuan Indonesia (LIPI)

4. Akademi Ilmu Pengetahuan Indonesia

5. Tim Olimpiade Fisika Indonesia

Disusun Ulang Oleh: 

Arip Nurahman

Pendidikan Fisika, FPMIPA, Universitas Pendidikan Indonesia
&
Follower Open Course Ware at MIT-Harvard University, USA.

Semoga Bermanfaat dan Terima Kasih