Galilei's astronomical discoveries using the telescope and their evaluation found in a writing‐calendar from 1611

Yearly calendars were a mass‐produced article in early modern times and had an enormous importance in everyday life. Besides a first part, the Calendarium with the monthly tables, they contain a second part, the astrological Prognosticum. At first, the two parts were sold separately. In the second half of the 17th century, the parts were designed as a unity and sold together. The calendars in quart format contain texts which are so interesting that historical research should give them more consideration. Such a text is found, e.g., in the second part of the calendar for 1611, written by Paul Nagel, astronomer and rector of the school in Torgau. Nagel informs about Galilei's discoveries with the telescope. The (Latin) text was written in August 1610. This text is presented and put into perspective in the scientific debates of the time about the telescope as a new invention with consequences to philosophy (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Solving the controversy about the astronomical significance of the rock formation “Teufelstein” in Styria

As two very controversial surveys of the rock formation “Teufelstein” exist in literature (H. Haupt versus H.M. Maitzen as well as W. Schlosser), a photographic documentation of solar and lunar rising and setting points throughout a whole year as well as a remeasurement with a solar compass was carried out on the spot. The result is that the formation is not an accurate solar marker but could only have served as a warning peg for the summer solstice setting point (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A review of East Asian reports of aurorae and comets circa AD 775

Given that a strong ¹⁴C variation in AD 775 has recently been suggested to be due to the largest solar flare ever recorded in history, it is relevant to investigate whether celestial events observed around that time may have been aurorae, possibly even very strong aurorae, or otherwise related to the ¹⁴C variation (e.g. a suggested comet impact with Earth's atmosphere). We critically review several celestial observations from AD 757 to the end of the 770s, most of which were previously considered to be true, and in some cases, strong aurorae; we discuss in detail the East Asian records and their wording. We conclude that probably none among the events after AD 770 was actually an aurora, including the event in AD 776 Jan, which was misdated for AD 774 or 775; the observed white qi phenomenon that happened above the moon in the south‐east was most probably a halo effect near the full Moon – too late in any case to be related to the ¹⁴C variation in AD 774/5. There is another report of a similar (or identical) white qi phenomenon above the moon, reported just before a comet observation and dated to AD 776 Jan; the reported comet observed by the Chinese was misdated to AD 776, but actually sighted in AD 767. Our critical review of East Asian reports of aurorae circa AD 775 shows some very likely true Chinese auroral displays observed and reported for AD 762; there were also several events prior to AD 771 that may have been aurorae but are questionable. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Chinese comet observation in AD 773 January

The strong ¹⁴C increase in the year AD 774/5 detected in one German and two Japanese trees was recently suggested to have been caused by an impact of a comet onto Earth and a deposition of large amounts of ¹⁴C into the atmosphere (Liu et al. 2014). The authors supported their claim using a report of a historic Chinese observation of a comet ostensibly colliding with Earth's atmosphere in AD 773 January. We show here that the Chinese text presented by those authors is not an original historic text, but that it is comprised of several different sources. Moreover, the translation presented in Liu et al. is misleading and inaccurate. We give the exact Chinese wordings and our English translations. According to the original sources, the Chinese observed a comet in mid January 773, but they report neither a collision nor a large coma, just a long tail. Also, there is no report in any of the source texts about “dust rain in the daytime” as claimed by Liu et al. (2014), but simply a normal dust storm. Ho (1962) reports sightings of this comet in China on AD 773 Jan 15 and/or 17 and in Japan on AD 773 Jan 20 (Ho 1962). At the relevant historic time, the Chinese held that comets were produced within the Earth's atmosphere, so that it would have been impossible for them to report a “collision” of a comet with Earth's atmosphere. The translation and conclusions made by Liu et al. (2014) are not supported by the historical record. Therefore, postulating a sudden increase in ¹⁴C in corals off the Chinese coast precisely in mid January 773 (Liu et al. 2014) is not justified given just the ²³⁰Th dating for AD 783 ± 14. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

No evidence for an early seventeenth‐century Indian sighting of Kepler's supernova (SN1604)

In a recent paper in this journal, Sule et al. (2011) argued that an early 17th‐century Indian mural of the constellation Sagittarius with a dragon‐headed tail indicated that the bright supernova of 1604 was also sighted by Indian astronomers. In this paper it will be shown that this identification is based on a misunderstanding of traditional Islamic astrological iconography and that the claim that the mural represents an early 17th‐century Indian sighting of the supernova of 1604 has to be rejected. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

干支回推-天文年代学的一种新方法

“干支回推法”是针对中国历史时期所特有的干支材料而设计的新天文年代学方法．以一组假设的材料为例,系统地给出了该方法的完整求解过程．指出该方法的优势在于准确高效,能有效地处理某些年代学难题．此外,除材料的公历日期外还能将当时的历法细节一同迭代解出．     

Analysis of Korean astronomical records with Chinese equatorial coordinates

The historical documents of ancient Korea contain abundant records on various astronomical phenomena. The historical documents of the Joseon dynasty contain observational values based on Chinese equatorial coordinate system (i.e., angular distances from the reference star of a lunar mansion and the North Pole). However, quantitative analysis of the observational values has not been carried out. In this study, we investigate the observational accuracy during the Joseon dynasty by comparing the astronomical records of Joseonwangjo Sillok (Annals of the Joseon Dynasty) and Seungjeongwon Ilgi (Daily Records of the Royal Secretariat) with modern astronomical calculations. Consequently, we find that the observational accuracy during the early Joseon dynasty was approximately 1°.2 and 0°.3 in the right ascension and declination, respectively. On the other hand, we find that the observational accuracy during the later Joseon dynasty was considerably poor. Observations of Halley's comet in 1759 were off by approximately 7° in declination. We believe that further investigation is required to verify the reason for this poor accuracy. Thus, we list the complete records used for this study in the appendix. We believe that these records also can contribute to modern studies on phenomena such as supernovae or Halley's comet. In conclusion, we believe that this study is useful for understanding ancient Korean astronomical records, even though we have considered a small number of astronomical events (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Statistical algorithms for identification of astronomical X‐ray sources

Observations of present and future X‐ray telescopes include a large number of ipitous sources of unknown types. They are a rich source of knowledge about X‐ray dominated astronomical objects, their distribution, and their evolution. The large number of these sources does not permit their individual spectroscopical follow‐up and classification. Here we use Chandra Multi‐Wavelength public data to investigate a number of statistical algorithms for classification of X‐ray sources with optical imaging follow‐up. We show that up to statistical uncertainties, each class of X‐ray sources has specific photometric characteristics that can be used for its classification. We assess the relative and absolute performance of classification methods and measured features by comparing the behaviour of physical quantities for statistically classified objects with what is obtained from spectroscopy. We find that among methods we have studied, multi‐dimensional probability distribution is the best for both classifying source type and redshift, but it needs a sufficiently large input (learning) data set. In absence of such data, a mixture of various methods can give a better final result.We discuss some of potential applications of the statistical classification and the enhancement of information obtained in this way. We also assess the effect of classification methods and input data set on the astronomical conclusions such as distribution and properties of X‐ray selected sources. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

“A red cross appeared in the sky” and other celestial signs: Presumable European aurorae in the mid AD 770s were halo displays

The interpretation of the strong ¹⁴C variation around AD 775 as one (or several) solar super‐flare(s) by, e.g., Usoskin et al. (2013) is based on alleged aurora sightings in the mid AD 770s in Europe: A red cross /crucifix in AD 773/4/6 from the Anglo‐Saxon Chronicle, inflamed shields in AD 776 (both listed in the aurora catalogue of Link 1962), and riders on white horses in AD 773 (newly proposed as aurora in Usoskin et al. 2013), the two latter from the Royal Frankish Annals. We discuss the reports about these three sightings in detail here. We can show that all three can be interpreted convincingly as halo displays: The red cross or crucifix is formed by the horizontal arc and a vertical pillar of light (either with the Sun during sunset or with the moon after sunset); the inflamed shields and the riders on white horses were both two mock suns, especially the latter narrated in form of a Christian adaptation of the antique dioscuri motive. While the latter event took place early in AD 774 (dated AD 773 in Usoskin et al. 2013), the two other sightings have tobe dated AD 776, i.e. anyway too late for being in connection with a ¹⁴C rise that started before AD 775. We also sketch the ideological background of those sightings and there were many similar reports throughout that time. In addition, we present a small drawing of a lunar halo display with horizontal arc and vertical pillar forming a cross for shortly later, namely AD 806 June 4, the night of full moon, also from the Anglo‐Saxon Chronicle; we also show historic observations of halo phenomena (mock suns and crosses) from G. Kirch and Hevelius – and a modern photograph. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the history of some explicit formulae for solving Kepler's equation

In this paper we examine, in their historical context, some approximate solutions for Kepler's equation. These explicit formulae, obtained by Trembley, Pacassi, Fergola, and Horrebow, had not a great diffusion and were thus often rediscovered by other astronomers. We will prove that the formulae are equivalent and, moreover, we will give an evaluation of the error. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Dwingeloo – the golden radio telescope

The Dwingeloo 25‐m telesope, inaugurated in 1956, has played a major role in research for half a century. We trace its history back to its conception in 1944, and summarize its main achievements. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The 1998 outburst and history of the June Boötid meteor shower

The June Boötid meteor shower (sometimes referred to as the Draconids) surprised a number of regular and casual observers by an outburst with maximum zenithal hourly rates (ZHRs) near 100 on 1998 June 27 after a quiescent period of several decades. A total of 1217 June Boötid meteors were recorded during regular visual meteor observations throughout this outburst. An average population index of r =2.2±0.10 was derived from 1054 shower magnitude estimates. The broad activity profile with ZHR>40 lasting more than 12 h and the large spread of apparent radiants in 1998 resemble the 1916 and 1927 outbursts. The peak time is found to be at about λ _⊙=95°.7 (2000.0); peak ZHRs are of the order of 200, whereas reliable averages reach only 81±7. The period of high ZHRs covered by a single observer implies a full width at half-maximum of 3–4 h. The resulting maximum flux of particles causing meteors brighter than +6.5 mag is between 0.04 and 0.06 km⁻² h⁻¹. The average radiant from photographic, radar and visual records is α =224°.12, δ =+47°.77. The observed activity outbursts in 1916, 1927 and 1998 are not related to the orbital period or the perihelion passages of the parent comet 7P/Pons–Winnecke. These are probably a consequence of the effects of the 2:1 resonance with Jupiter.     

Venus 1882 and Jean‐Charles Houzeau

This paper focuses on one particular type of telescope – the heliometer – designed for solving one specific basic problem in astronomy: the scale factor of the solar system. One very special instrument of this type was the “heliometer with unequal focal lengths” designed by the Belgian astronomer Jean‐Charles Houzeau for the 1882 transit of Venus. We also draw attention to the most interesting personality of Houzeau, and to his social engagement that went much beyond his work as a scientist (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Multiverses of the past

More than 2000 years ago, Epicurus taught that there are an infinite number of other worlds, both like and unlike ours, and Aristotle taught that there are none. Neither hypothesis can currently be falsified, and some versions of current multiverses perhaps never can be, which has contributed to occasional claims that “this isn't science!” (a common complaint about cosmology for centuries). Define “cosmos”, or “world”, or “universe” to mean the largest structure of which you and the majority of knowledgeable contemporaries will admit to being a part. This begins with the small, earth‐centered worlds of ancient Egyptian paintings, Greek mythology, and Genesis, which a god could circumnavigate in a day and humans in a generation. These tend to expand and become helio‐rather than geo‐centric (not quite monotonically in time) and are succeeded by various assemblages of sun‐like stars with planets of their own. Finite vs. infinite assemblages are debated and then the issue of whether the Milky Way is unique (so that “island universes” made sense, even if you were against the idea) for a couple of centuries. Today one thinks as a rule of the entire 4‐dimensional space‐time we might in principle communicate with and all its contents. Beyond are the modern multi‐verses, sequential (cyclic or oscillating), hierarchical, or non‐communicating entities in more than four dimensions. Each of these has older analogues, and, in every milieu where the ideas have been discussed, there have been firm supporters and firm opponents, some of whose ideas are explored here. Because astronomical observations have firmly settled some earlier disputes in favor of very many galaxies and very many stars with planets, “other worlds” can now refer only to other planets like Earth or to other universes. The focus is on the latter (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Troughton & Simms transit circle of Coimbra Astronomical Observatory from the 1850s: An example of the dissemination of technological developments

Yesterday, as today, technological developments led by large and expensive instrumental projects are later on disseminated to smaller and more affordable devices. In 1847, Airy requested a new transit circle for the Greenwich Observatory. When the first observation was performed, on 4 January 1851, Airy's Greenwich Transit Circle (ATC) was the largest instrument of its class in the world. The construction of the ATC implied solving several technical difficulties, for example, the maintenance of the instrument rigidity and the illumination of the graduated circle and telescope field of view. After the ATC completion Troughton & Simms stand at the 1851 Great London Exhibition included two small transit instruments which were praised for their telescope field of view/eyepiece wires illumination. One of which, was based upon the design implemented beforehand on the ATC. In this paper we will discuss the field and eyepiece wire illumination innovations introduced on the ATC and the Simms transit instruments exhibited in 1851. We will also describe the small Troughton & Simms transit circle currently belonging to Coimbra Astronomical Observatory collection that is, we believe, one of the earliest implementation of this ATC lead development (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

邢云路对《授时历》日躔过宫推步的改进

考察明末邢云路所撰《古今律历考》中述及的日躔推步实例与先期恢复的《授时历》和《大统历》方法进行推步比对.采用邢云路改进的《授时历》法推步万历己亥岁(1599年)日躔交宫时间,结果与邢氏的标准偏差为5.93刻(=85.39 min),同时交宫夜半黄道宿度的偏差0.06古度(=0.059°);其中若扣除戌宫可能因数据错误产生的较大误差,则标准偏差将降为1.38刻(=19.87 min)和0.01古度(=0.0099°).其次,采用《大统历》计算该年日躔交宫,与邢云路计算的标准偏差为1.09刻(=15.70 min),交宫夜半黄道宿度的标准误差为0.05古度(=0.049°).据此可认为:基本恢复了邢氏的日躔推步方法;邢云路并未对《授时历》的日躔推步方法作本质上的改进,只是修改了其中的年长、周天分及宫界度.研究表明,邢氏所得《大统历》推交宫的结果与《授时历》偏差过大,原因在于其修改了《授时历》的参数,邢氏有厚《授时》薄《大统》之嫌.     

Newly found sunspot observations by Peter Becker from Rostock for 1708, 1709, and 1710

We present a few newly found old sunspot observations from the years AD 1708, 1709, and 1710, which were obtained by Peter Becker from Rostock, Germany. For 1709, Becker gave a detailed drawing: he observed a sunspot group made up of two spots on January 5, 6, and 7, and just one of the two spots was observed on January 8 and 9. We present his drawing and his explanatory text. We can measure the latitude and longitude of these two spots and estimate their sizes for all five days. While the spots and groups in 1708 and the spot on four of the five days in January 1709 were known before from other observers (e.g. Hoyt & Schatten 1998), the location of the spots in early January 1709 were not known before, so that they can now be considered in reconstructed butterfly diagrams. The sunspots detected by Becker on 1709 January 5 and 1710 September 10 were not known before at all, as the only observer known for those two dates, La Hire, did not detect that spot (group). We estimate new group sunspot numbers for the relevant days, months, and years. The time around 1708–1710 is important, because it documents the recovery of solar activity towards the end of the Maunder Grand Minimum. We also show two new spot observations from G. Kirch for 1708 September 13 and 14 as described in his letter to Wurzelbaur (dated Berlin AD 1708 December 19). (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Analysis of interval constants in calendars affiliated with the Shoushili

We study interval constants that are related to motions of the Sun and Moon,i.e., the Qi, Intercalation, Revolution and Crossing interval, in calendars affiliated with the Shoushi calendar(Shoushili), such as Datongli and Chiljeongsannaepyeon. It is known that these interval constants were newly introduced in the Shoushili calendar and revised afterward, except for the Qi interval constant, and the revised values were adopted in later calendars affiliated with the Shoushili. We first investigate the accuracy of these interval constants and then the accuracy of calendars affiliated with the Shoushili in terms of these constants by comparing times for the new moon and the maximum solar eclipse calculated by each calendar with modern methods of calculation. During our study, we found that the Qi and Intercalation interval constants used in the early Shoushili were well determined, whereas the Revolution and Crossing interval constants were relatively poorly measured. We also found that the interval constants used by the early Shoushili were better than those of the later one, and hence better than those of Datongli and Chiljeongsannaepyeon. On the other hand, we found that the early Shoushili is, in general, a worse calendar than Datongli for use in China but a better one than Chiljeongsannaepyeon for use in Korea in terms of times for the new moon and when a solar eclipse occurs, at least for the period 1281 – 1644.Finally, we verified that the times for sunrise and sunset in the Shoushili-Li-Cheng and Mingshi are those at Beijing and Nanjing, respectively.     

On the First Anthropic Argument in Astrobiology

We consider the little-known anthropic argument of Fontenelledealing with the nature of cometary orbits, given a year before the publication of Newton'sPrincipia. This is particularly interesting in view of the rapid development of therecently resurgent theories of cometary catastrophism and their role in the modern astrobiologicaldebates, for instance in the ``rare Earth' hypothesis of Ward and Brownlee.