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)     

Absolute astronomical accelerometry

Two distinct but fully compatible novel concepts are proposed here for solar/stellar velocity measurements. The first is that of absolute accelerometry proper. This involves two simultaneously, operating servo-control loops First, a variable path-difference Fabry-Perot interferometer is adjusted so that its bandpasses track the fluctuations of either a single spectral line (in the solar case, leading to the solar accelerometer), or of all lines simultaneously (stellar accelerometer). The second loop involves a tunable laser tracking one of the FP bandpasses. The net overall result is that a laser line tracks the stellar/solar ones: the problem of measuring Doppler-shift changes has been transferred from the incoherent to the coherent optics domain. One then measures the beat frequency generated by mixing the tunable laser beam with that of stabilized laser. Only velocity changes are accessible; the devices are true accelerometers, but absolute ones. All instrumental or spectral characteristics drop out; no calibration of any kind is required; hence, one may hope for an unusually low level of systematic errors. The second concept is that of optimum measurement of Doppler shifts as far as photon count limitations are concerned. A simple but so far never performed calculation leads to the fundamental RMS velocity error corresponding to a given spectral profile and photon count. One next shows that a dispersive spectrometer with an image detector may closely approach that limit provided direct access to a computer is available, and the signal is treated by a specific algorithm. This treatment being precisely the one used in the stellar accelerometer, our device is seen as the first proposed one approaching fundamental limits in this field; however, standard radial velocity measurements (not involving accelerometry) should also benefit from our proposal. A full calculation shows that a velocity error reduction of the order of 30 is within reach relative to the most efficient so far available device, i.e., CORAVEL. For faint objects, detector noise must be added, but the treatment remains demonstrably optimum. The two principal fields of application for absolute accelerometry are celestial seismology (a seismometer is nothing but an accelerometer), and the search for extra-solar planetary systems. In both cases a large number of objects will be accessible with a small telescope. One may also look for solar system accelerations (relative to some system of reference stars) due to any cause whatsoever: for instance a faint solar companion, or even gravitational waves.     

The development of astronomical interferometry

Astronomical interferometry was pioneered by Fizeau and Michelson in the 19^th century. In the 1920s, the first stellar diameters were measured. The development of radio interferometry began in the 1950s, and led to the construction of powerful synthesis arrays operating at cm, mm, and sub-mm wavelengths. Modern computer and control technology has enabled the interferometric combination of light from separate telescopes also in the visible and infrared regimes. Imaging with milliarcsecond resolution and astrometry with microarcsecond precision have thus become reality.     

天文常数研究的进展——IAU 2009天文常数系统

回顾了1900年以来LAU采用天文常数系统的简况,以及一些天文常数之间的数学关系,并描述了以前每次改变天文常数系统的主要因为.介绍了1991年以来IAU在天文常数方面的工作:包括IAU天文常数工作组和天文常数最佳估计值的情况.叙述了IAU 2009年天文常数系统替代IAU 1976天文常数系统的因为:随着人类对太阳系的探测,获得新的天文常数测定值;1991年以来在相对论框架下BCRS和GCRS的使用;P03岁差模型和MHB2000章动模型的采用.比较了IAU2009和1976天文常数系统的差异.最后介绍中国在天文常数方面工作的情况和今后工作的建议.     

Mass pick-up in astronomical flows

Many astrophysical sources are clumpy. The flows in the diffuse media in these sources are affected by the mass picked up through the ablation of the embedded clumps. The diffuse media-clump interfaces can be observable sources themselves. Flows in clumpy stellar wind blown bubbles, supernova remnants, quasar winds, cooling gas accreting on to galaxies, and in pre-galactic bubbles blown by energy input from young galaxies, are discussed. Pick-up has important chemical as well as dynamical effects in star forming regions. The natures of the interfaces are considered.Paper dedicated to Professor Hannes Alfvén on the occasion of his 80th birthday, 30 May 1988.     

First astronomical observatory in Lviv

This historical essay highlights the state of the art for astronomical researches in Lviv dating back to the end of 18th century, the information is given concerning earliest documentary substantiated astronomical observations held in Lviv. The circumstances of foundation and building astronomical Observatory at Jesuit College (University) are depicted, the foundation date is determined by archival materials, it is 15 of May, 1771. We have investigated the role played by Observatory during the incorporation of Galicia (Halychyna) into Austro-Hungarian empire. The biographical data are collected and arranged concerning prominent astronomers and engineers of those times, the lives of which were somehow connected to Lviv Observatory.     

Optical fibers in astronomical instruments

Summary This review is of current and projected applications of optical fibers to observational astronomy. The intent is to provide astronomers with a broad perspective on the subject, with the hope of encouraging productive use of optical fibers in the design of new instrumentation. The unique characteristics of fibers have been (or soon will be) exploited to advantage in several areas of astronomical instrumentation, including multiplexers for muti-object spectrographs, remote optical feeds for spectrographs and photometers, coherent beam recombiners for optical interferomety, and many miscellaneous applications. We discuss the most important such applications in detail, with reference to operational instruments wherever possible, and with emphasis on the optical properties of fibers and the engineering considerations encountered in their application to observational astronomy.     

Information content in astronomical images

We should like to point out that the special non-singular Bianchi type-I solution of no-scale supergravity, recently obtained by Barrow and Deruelle (1988), does not exist. The most general consistent non-singular Bianchi type-I solution has been derived recently by us (Lorenz-Petzold, 1988).     

Interferometric calibrations and astronomical calibrators

This chapter gives some indications on the selection of suitable astronomical calibrators for interferometric observations. After an introduction to interferometric calibrations, we will focus on the criteria, steps and tools developed by ESO to prepare VLTI observations and to select calibrators. Although the tools described here are focused on VLTI, the problem of astronomical calibrators is the same for the other interferometers and can be approached in the same way.     

Query driven visualization of astronomical catalogs

Interactive visualization of astronomical catalogs requires novel techniques due to the huge volumes and complex structure of the data produced by existing and upcoming astronomical surveys. The creation as well as the disclosure of the catalogs can be handled by data pulling mechanisms (Buddelmeijer et al. 2011). These prevent unnecessary processing and facilitate data sharing by having users request the desired end products. In this work we present query driven visualization as a logical continuation of data pulling. Scientists can request catalogs in a declarative way and set process parameters directly from within the visualization. This results in profound interoperation between software with a high level of abstraction. New messages for the Simple Application Messaging Protocol are proposed to achieve this abstraction. Support for these messages are implemented in the Astro-WISE information system and in a set of demonstrational applications.     

Super resolution for astronomical observations

In order to obtain detailed information from multiple telescope observations a general blind super-resolution (SR) reconstruction approach for astronomical images is proposed in this paper. A pixel-reliability-based SR reconstruction algorithm is described and implemented, where the developed process incorporates flat field correction, automatic star searching and centering, iterative star matching, and sub-pixel image registration. Images captured by the 1-m telescope at Yunnan Observatory are used to test the proposed technique. The results of these experiments indicate that, following SR reconstruction, faint stars are more distinct, bright stars have sharper profiles, and the backgrounds have higher details; thus these results benefit from the high-precision star centering and image registration provided by the developed method. Application of the proposed approach not only provides more opportunities for new discoveries from astronomical image sequences, but will also contribute to enhancing the capabilities of most spatial or ground-based telescopes.     

Integral methods in astronomical spectroscopy

We discuss the milestones of development of the integral methods used in the optical spectroscopy of astronomical objects. We analyze the reasons why some of these methods did not get wide practical application. We demonstrate that a combination of integral methods with multichannel detectors allow increasing the efficiency of the existing astronomical telescopes while pursuing the given spectroscopic programs. A technique of radial velocity measurements not susceptible to positional errors, typical of diffraction spectroscopy, is as well discussed.     

Conceptual approach to astronomical problems

New technical capabilities have brought about the sweeping growth of the amount of data acquired by the astronomers from observations with different instruments in various parts of the electromagnetic spectrum. We consider conceptual approach to be a promising tool to efficiently deal with these data. It uses problem domain knowledge to formulate the tasks and develop problem-solving algorithms and data analysis methods in terms of domain concepts without reference to particular data sources, and thereby allows solving certain problems in general form. We demonstrate the benefits of conceptual approach by using it to solve problems related to search for secondary photometric standard candidates, determination of galaxy redshifts, creation of a binary and multiple star repository based on inhomogeneous databases, and classification of eclipsing binaries.We formulate and solve these problems over specifications of astronomical knowledge units such as photometric systems, astronomical objects, multiple stars, etc., and define them in terms of the corresponding problem domains independently of the existing data resources.     

Impact of astronomical research from different countries

The impact of astronomical research carried out by different countries has been compared by analysing the 1000 most‐cited astronomy papers published 1991‐8 (125 from each year). 61% of the citations are to papers with first authors at institutions in the USA, 11% in the UK, 5% in Germany, 4% in Canada, 3% in Italy and 3% in France. 17% are to papers with first authors in ESO countries. The number of citations is approximately proportional to the number of IAU members in a given country. The number of citations per IAU astronomer is highest in the USA, Switzerland and the UK. Within continental Europe, the number of citations per IAU astronomer varies little from country to country, but is slightly higher in the north than in the south. The sample of 1000 papers maps regional subject preferences. 62% of the extragalactic papers in the sample were published from the USA, 15% from the UK, 23% from other countries (mainly in continental Europe). 62% of the papers on stars were also published from the USA, but the fractions from the UK and from other countries are 2% and 36% respectively. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Formation and structure of neutrino astronomical objects

Neutrinos with non-zero mass could gather to form a new kind of astronomical bodies: the Neutrino Astronomical Objects (NAO). We have investigated the mechanism of their formation and the relation of this formation to that of the galaxies, ascertained their e, p, He⁴ content, whose presence should produce a series of observable effects. NAOs are a peculiar kind of heavenly bodies with many new properties. They have a linear size of the order of 100 pc, a total neutrino content of the order of 10¹⁴M and an e, p, He⁴ content of the order of 10⁹M.     

Some new astronomical facilities in China

For the 1990's, plans for some astronomical facilities and related researchers are being carried out in China. In this report we describe in some details the plans of radio astronomical facilities, 150/220 cm Schmidt telescope, and experiments on porcelain mirror material.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 2, 1988.     

Local effects in pure astronomical refraction

Auf der Basis von sich über einen Zeitraum von 10 Jahren erstreckenden aerologischen Messungen für den Raum Pozna$ (φ = 52° 24′, $LD = 1^h 07^m.5, h₀ = 85 m) wurde eine statistische Analyse sowohl zeitlicher als auch lokaler Effekte der astronomischen Refraktion durchgeführt. Es wurden keine wahrnehmbaren Effekte zeitlicher Variationen in den höheren Atmosphärenschichten verzeichnet. Damit kann die momentane lokale Refraktion recht exakt durch die mittlere lokale Refraktion approximiert werden, die sich aus einem momentanen Brechungsindex n₀ auf dem Grundniveau bestimmt. Es gibt jedoch eine systematische Differenz zwischen der Standardrefraktion, berechnet mittels n₀, und der lokalen Refraktion. Dieser Unterschied erweist sich als recht deutlich, so da$sZ es sinnvoll ist, eine lokale Korrektur für die Standardrefraktion einzuführen. Für Poznan ist diese Korrekturgrö$sZe negativ und beläuft sich auf 0″.01 fürz₀ = 60°, 0″.1 für z₀ = 77°, 1″ für z₀ = 85°, und 3″ für z₀ = 87°. At z₀ = 82°. Für Werte grö$sZer als z₀ = 82° überschätzt die Korrektur die Varianz der stochastischen Refraktionsanomalien (Bildbewegung), die über einen Zeitraum von 60 s integriert wurde. Diese Arbeit gibt eine Antwort auf die schon lange diskutierte Frage, ob wir eine lokale reine Refraktion anwenden sollten und wenn ja, in welcher Weise.