更新日 2023.11.17
7月15日 引き続いて天気不良。この夕がた一寸晴れた。Van Gent彗星を雲を通して見る、薄い。写真を撮るも雲の為とても薄く、唯位置だけ分かる。
Graphical method(Bonn星図)より得たる位置は次の如し。
1941年7月15日 9時7.5分
1855.0 α= 13h 41.3m δ= +21°45′
1941.0 α= 13h 45m 22,7s δ= +21°19′1.7″
尚、この晩、1.5インチのアイピースを15cm鏡につけ見るに像頗るよし。εLyr(こと座ε星)をも少し強いアイピースで見れば4重に見得るらしい。
また、2.5インチのObjective Prism(対物プリズム)の表面が黴たのと、又充分平面でなかりしため、磨き直す。だいぶよくなりしも未だ充分なる平面ではない。
Popular Astronomy Vol.XLI No.6 June-Huly 1933.
Amateur Meteor Photography by P. M. Millman.
使用のレンズは、F3.5 F2 位よりもF4.5レンズがよい。乾板のField(視野)は30°位まで像がよいものを使用すべし。
乾板はパンクロ(panchromatic=汎色乾板=臭化銀乾板よりも色彩によく感光するようにした写真乾板またはフィルム)の如きも良いもの。
流星の撮れるchance(チャンス)は流星雨の時が最も収穫が多い。暗夜の晴れたときは1時間の露出でも差支えないが月が出た時など短い露出でないとかぶる(被る= 写真で、現像過程やフィルムの欠点のため、または露出過度のため、くもりができて不鮮明になること)。
流星のスペクトル写真は一層有益な研究である。その装置には、F4.5レンズfocus(焦点距離)25cm程度でよい。レンズはZeiss Tessar、Voighlander Skoparなど優秀である。
Spectra(スペクトル)の分散は、Hβ- Hγ= 0.5 -1.5mm位になればよい。
Jena(イエナ)UV3199のガラスで30°- 40°の角のプリズムがよい。又、20°- 30°角でJena 0340、0602もよい。Focal length(焦点距離)13.5cm F4.5のものならばlight flint(軽フリント) 30°- 40°のものを用う。
著者は、Voigtlander AvusでSkoparレンズ F4.5 13.5cm焦点のものを用い30°のsilicate flintのプリズム使用。
1秒= 20- 30回転のshutter(シャッター)をsynchronous motor(シンクロナス・モーター)につけて、レンズの前でshutterを切るようにすれば頗るよい結果を得る、(普通の流星の跡trailのとき)
Prism minimum deviation(プリズムの最少偏差)の方向に取付ける。
∠C = ∠Bとなるようにプリズムは全面が
∠E = (A - D)/ 2となればよい。
白紙の上に直線を引き、プリズムで見てその線が寄る点とOに線を引けばDを得る。
Prism(プリズム)の位置の精確よりももっと大切なることは、prismがしっかりとカメラに取り付けてあることである。又、試写によりてピントをよく合わせることも大切である。
スペクトルが流星の進行に直角に出るようにすることも大切であって、大きい流星は大てい垂直に近く下るものであるから∠Aが、
地平線に垂直の位置になるようにカメラを据える。
乾板面には夏ならばベガ、冬ならばシリウスのスペクトルを入れて比較する要がある。
Sporadic meteor(散在流星)は、大体地平上43°あたりで出るから此の角度にレンズを向ければよい。流星雨が地平線に近いとき、この反対の地平線上に向けた他のカメラを置くのもよい。
Popular Astronomy Vol. XV, No.1907. 1月号にMetcalfが写真より彗星を発見せるplate(乾板)が出ておる。それによれば、1つの乾板にdouble exposure(2重露出)してある。星はRA(赤経)に2重に出ているが、彗星はその前後に運動が見えておる。
即ち、次の図の如くである。焦点の長い望遠鏡では半時間位でこれ位の位置の変化が見えよう。
---------------------------------
尚、Metcalfのcomet seeker(彗星捜索機)は7インチ、field(視野)1°1/2、Zacchens Danielの望遠鏡 4インチpower 18(18倍)、field 2°(視野2°)、これにて平均1時間に1ヶの薄い流星に出合う。
Pop. Astronomy 1941 Jun vol.XLIX Vol. No.6
The Physical Condition of novae at Minimum By Dean B, Mclanghlin.
Average absolute magnitude of novae at maximum -7.
Average range from minimum to maximum 11 magnitudes, therefore at minimum absolute magnitude is +4.0
Photographically at least novae are very nearly of the same luminosity before and after the outbreak.
Spectra of novae after the end of decline showed continuous spectra extending well into the violet, indicating temperature comparable to early B and O type stars.
Many of these had more or less conspicuous emission lines of hydrogen and ionized helium and occasionally neutral helium, Emission at 4650 ○. No absorption lines Violet extension indicates Temperature about 30,000°K.
Assumed temperature for post-nova star = 50,000°K.
For temperatures above 30,000°K the well known approximate formula for radius
Log R = 5900/T - 0.2Mv - 0.02 (1)
Becomes inaccurate. By bolometric magnitude
Slefan-Boltzmann law
Mb = 10 log〔T0/T(star)〕- 5 log R + M0 (2)
T0、M0 effective temperature and bolometric
Absolute magnitude of the sun. T, Mb same for star, T0 = 6,000°K, M0 = +4.8 we obtain
Log R = 8.52 -2 log T star -0.2Mb (3)
In table Ⅰ for a post-nova star of visual absolute magnitude +4.0 and various assumed temperatures gwen in the firu column of Ⅱcolumn from Pike’s table, radius computed from (3)Reduced bolometric magnitude obtained by applying to the data of the third colmn the term
2 log〔T/5200〕mass is obtained by
Eddington’s table of mass-luminosity.
(1)関口鯉吉著『天体物理学』147ページ、
The calculations for 30,000°and 75,000, 100,000 are pretty surely outside the allowable range, 50,000°is close to the upper limit, densities are high but they are much smaller then true white dwarfs.
Conclusion,
Ex-novae are sub-dwarfs of rather high temperature, with luminosities, radii, and densities intermediate between those of main sequence stars and those of true white dwarfs. Novae to special class of stars. All novae may repeat in intervals of many thousands of years.
Publications of the Astronomical society of the Pacific. Vol.53 no.313 1941 June.
Supernovae by Edwin Hubble.
Supernova is very bright, since 1885 40 supernovae have for recorded in 36 stellar systems (nebulae) since 1937 22 outbursts have been observed, of which 18 were discovered at Palomar (14 by Zwicky 4 by his assistant Johnson). Appearance is once in several centuries per nebula. No preference to the types of nebulae.
Supernova divided into two groups Ⅰ, Ⅱ.
Group Ⅰ, hight curve is similar to the normal nova. Lraze up a million fold or move within a space of a few days. Overage maximum of 100 million suns, comparable with the total luminosity of an overage stellar system. Following maximum the stars fade rapidly at first then after a few weeks slowly, loosing about 1/3 of their light each month.
Example, Outburst in IC 4182, This nebula is a dwarf stellar at a distance about 3 million light years. In August 1937 a supernova brazed out to a max. of about 600 million suns, nearly 100 times brighter than the nebula itself.
The amount of energy suddenly radiated in one day was as much the sun radiate in one and a half million years.
The spectra are radically different from those of any other known phenomena, none of the major features has yet been identified. Before max. extremely broad emission bands appeared. In normal novae emission bands do not appear until after maximum. In photographic region of spectra, a pattern soon forms which does not change in composition but drifts bodily toward the red as time goes on. The only recognizable features are two relatively narrow bands in the red believed to represent the oxygen 1 line at λ6300, λ6364. These bands appear some 5 to 6 months after max.
Group Ⅱ、reaches maximum of the order of 10 million suns, light curve shows .
Auspicious shoulder of descending branch
Exp. Nova in NGC 4725, in 1940. Spectra: cnotinuous of very hot star. Emission bands appeared 4 or 5 days after max. as the case of normal novae, indicated a velocity of expansion of the order of nearly 4000 miles per scond.
Supernovae appear in our system once in several centuries, novae of tycho 1572, Chinese and Japanese nova of 1054.
Tycho nova appeared in Cassiopeia, its brightness rivaled Venus, visible in full daylight.
From Chinese record nova of 1054 has appearance in Crab nebula in Taurus M1. Brightness was as Jupiter in Japanese record. At maximum must have been of the order of 300 million suns. At the center of crab nebula are two stars, one is yellow, by its proper motion this is not associate with the nebula. The other is so abnormal that it is believed as supernova at preaent its magnitude is 1616, its luminosity as about the sun.
Supernova in NGC 3254 in March 25, 1941.
NGC 3254 α= 10h 23m 42s δ= +30°0.1′
its distance 7 million light years, nova at maximum brightness -12.
Supernovaの○線
発 見 |
位 置 |
1941年5月25日 |
α= 10h23m 42s δ= +30°0.1′ |
発 見 者 |
星 雲 |
J. Johnson |
NGC 5254 |
|
NGC 4559 |
< 5.にもどる | 7.にすすむ > |