In the fall of 1920 two young scholars happened to meet in London and found they had many interests in common in laboratory spectroscopy and astrophysics. One was an Indian and the other a Japanese, and their paths crossed as they visited American and European centers to learn the tools and techniques of the quantum theory. The young Japanese scholar, T. Takamine, whose home base was then the Institute of Physical and Chemical Research in Tokyo, was delighted to have met Meghnad Saha, from Calcutta, who was just putting the finishing touches on his fourth paper on ionization equilibrium in the atmospheres of the sun and stars. When they met, Takamine and Saha spoke of Sommerfeld’s theories, and pledged to keep in touch. Thus began a correspondence that lasted for some twenty years, as Takamine returned to Japan from his long visits to American and European observatories and spectroscopic laboratories, and Saha returned to India. Of the two, Takamine had stayed the longer time in the West, mainly at Mount Wilson where he was in residence through much of 1919 working with John Anderson and A. S. King, and published on the ”The Stark Effect for Metals.” Takamine also returned to Mount Wilson in 1924, and toured many spectroscopic laboratories in the United States continuing to hone his interests and technique. Elsewhere I have examined Saha’s contacts with western astrophysics. Here I examine briefly how Takamine established and maintained contacts in the West and why he did so.

In the IAU, there is the Commission 46 “Teaching of Astronomy” to which at least one representative from each member country belongs. At an occasion of the Asian-Pacific regional meeting of the IAU held in Beijing in 1987, there was a resolution to set up a committee of Teaching of Astronomy in the Asian-Pacific region. Since then, a session of the Teaching of Astronomy has been hold at each regional meeting.

Recently Catherine Jami and I have found the manuscript of the Lifa wenda Dialogue on Astronomy) by Jean-Francois Foucquet (Fu Shengze , 1665-1741) at British Library. Together with the other, partial, but, otherwise identical, version, which she had located at the Vatican Apostolic Library, the manuscript, especially Book V, Part 1, from the British Library, gives us the detail of how Kepler’s forst and second Laws was introduced into China as early as in the 1710’s. This means that we can go back in the history of the introduction more than two decades earlier than the so far believed date.

There are of the order of 30 astronomers with research records and another 40-50 with substantial education in astronomy and astrophysics. Geographically, astronomical and astrophysical research is concentrated mainly at Shiraz University (cosmology and photometric observations), Sharif University of Theran (cosmology and gamma-ray astronomy), Tabriz University (binaries and solar physics), Meshad University (binaries and interstellar matter), Zanjan University (stellar dynamics, radio astronomy) and the Institute for Advanced Studies in Basic Sciences, Zanjan (stellar and stellar systems studies).

The period 1850-1910 was a “golden age” in Australian astronomy, with the establishment of professional observatories, substantial growth of popular interest in astronomy, establishment of a network of significant private observatories across the nation, and formation of Australia’s earliest astronomical groups and societies.

During this period, amateur astronomers were able to make a significant contribution internationally to positional astronomy. This paper briefly examines amateur-professional relations in Australian astronomy at the time, and the interplay of power and politics.

Delisle, born in 1688 April 4, is well known as a collector of astronomical data from all over the world. Part of his manuscripts are preserved in the Paris Observatory Library. He is said to have collected all available astronomical data at the time he was in activity in France and in Russia where he spent more than twenty years. He had more correspondents and among them, in Asia, Father Gaubil, of which more than one hundred letters are in the Paris Observatory Archives, providing priceless informations to astronomical researchers, historians and others.

Over the last few decades phenomena involving high energy particles (mostly electrons) and/or photons have become increasingly part of the astronomical work. Opening new spectral windows has revealed many phenomena that have deeply changed our perception of the Universe. High energy astrophysics, as this field of astronomy is known, is now very well integrated in the astronomical research. This is shown by the fact that the high energy astrophysics results are published in the leading astronomy and astrophysics journals of the world rather than anywhere else. Nonetheless, this still young field has not yet quite found its way in the structure and working of the IAU.

I have been asked to provide some general introduction to the topic of jets and high energy transients. I have chosen to do this by asking seven questions that seem to be timely following recent observational and theoretical developments, the most important of which may be the growing realization that the extragalactic- massive black hole and Galactic-stellar mass black hole manifestations of these phenomena provide two complementary ways of viewing a common physical mechanism. I have also chosen to illustrate these questions using one specific source in each case. The page limits prevent me from giving the answers. They also prohibit my even attempting to give a skeletal bibliography over so large a field. Fortunately almost all of these topics will be covered in greater depth during this meeting.

In the last solar maximum, gamma-rays associated with solar flares were observed with GRANAT, GAMMA-1, CGRO and YOHKOH. The gamma-ray energies ranged from 100 keV to a few GeV. We obtained several new findings of gamma-ray emission on the Sun: (1) Gamma-ray production in the corona, (2) GeV gamma-ray production in very long duration flares, (3) Electron-rich flares, (4) Gamma-ray lines and solar atmospheric abundances and (5) Possible location of gamma-ray emission. We present the observations of these new findings and discuss high energy phenomena relating to particle acceleration and gamma-ray production during solar flares.

We review recent results obtained from the analysis of the solar flare gamma ray line emission:

• (a) The gamma ray derived ambient elemental abundances show that the First Ionization Potential (FIP) effect already sets in at relatively low altitudes in the solar atmosphere.

• (b) The composition of the flare accelerated particles that produce the gamma rays exhibit heavy element and 3He abundance enhancements that are typical for impulsive flares. Unlike the solar energetic particle (SEP) observations in interplanetary space, the gamma ray method allows us to trace the time development of these enhancements.

• (c) Solar flare gamma ray spectroscopy provides the most direct measure of the abundances of the two very high FIP elements, He and Ne, in subcoronal regions leading to somewhat higher abundances than the generally accepted values.

• (d) The high intensities of the aa lines observed from a number of flares imply a high (≳ 0.1) ambient He/H and/or accelerated α/p.

• (e) There are indications for the isotopic fractionation of He from the photosphere to corona that has important implications on the mechanism of solar wind acceleration, the protosolar deuterium abundance and Galactic chemical evolution.

The main strengths of ROSAT [1] are its high quality imaging of extended sources and its large sensitivity for the detection of point sources. In the all-sky survey the diffuse X-ray emission was mapped with a resolution of 12 arcmin [2]. The number of point sources detected in the survey is ≈ 80 000 [3]. In addition more than 80 000 sources have been found in the ≈ 6 500 fields observed with the PSPC and HRI until now in the course of the pointed programme. A wealth of information about source variabilities has been extracted both from the all-sky survey and from the pointed observations, as well as from a combination of both.

We discuss recent detections of time-variable gamma-ray sources near the Galactic plane. A new bright gamma-ray transient was detected by EGRET in June 1995 near the Galactic center (GRO J1838-04). Also one of the most interesting unidentified gamma-ray sources in the plane, 2CG 135+1, was recently shown to be variable. Both GRO J1838-04 and 2CG 135+1 share many characteristics: variability of the gamma-ray flux within days/weeks, occasional peak gamma-ray emission of comparable flux (˜ 4 x 10-6ph cm-2s-1), absence of radio-loud spectrally-flat AGNs or prominent radio pulsars within their error boxes, lack of strong X-ray and/or hard X-ray counterparts. These characteristics do not match those of either gamma-ray blazars or isolated pulsars. Therefore, GRO J1838-04 and 2CG 135+1 provide strong evidence for the existence of a new class of variable gamma-ray sources.

The discovery of the association between relativistic radio jets and X-ray events in GRS 1915+105 (Mirabel and Rodriguez, 1994) and GRO J1655-40 showed that strong radio flares (Harmon et al, 1994) in general, and jet ejection (Hjellming and Rupen, 1994) in particular, could be identified with features in hard X-ray events. This has caused us to re-think the interpretation of the radio events in X-ray transients, and has made multi-wavelength observations even more important. In this paper the focus is on the connection between X-ray and radio events as seen since 1994 in GRS 1915+105, GRO J1655-40, GRO J1719-24, GRO J1739-278, Cyg X-3, Cyg X-l, and Sco X-l.

We study the formation of low-mass X-ray binaries with a black hole as accreting object. The performed semi-analytic analysis reveals that the formation rate of black holes in low-mass X-ray binaries is about two orders of magnitude smaller than that of systems with a neutron star as accretor. This is contradicted by the six observed systems, which are all transients, which suggest that the majority of these systems has not been seen jet. The birthrate for both type of objects are expected to be similar (for reviews see Cowley 1992, Tanaka & Lewin 1995).

Binary relativistic stars merging — the most powerful high energy transient in the Universe: Lmerging ˜ Mc2/Rg/c = c5/G ˜ 1058 erg/s. That is equal to Planckian luminosity (Lipunov 1992) Lplanck = EPlanck/tplanck = C5/G.

Since those reviews there have been very important new developments. First, a surprisingly new animal, GRO J1744—28 (better known as the Bursting Pulsar), made its debut in 1995. Second, but NOT last, in 1996/97 kHz pulsations were discovered in the persistent emission of several burst sources, and near coherent pulsations were detected in type I X-ray bursts.

It has long been suggested that turbulence provide viscous torques to transport angular momentum outward and flow mass inward in accretion disks (von Weizsäcker 1948, Shakura & Sunyaev 1973). Recent advances in subject of understanding of accretion disk turbulence are mach linked with magnetised disks (cf. Vishniac & Diamond 1992, Balbus, Gammie & Hawley 1994, Brandenburg et al. 1995, Stone et al 1996). However, not all the disks are magnetically coupled (see Balbus, Hawley & Stone 1996). Two different sources that are able to sustain turbulence in not magnetised accretion disk are the following:

Supersoft X-ray sources are a new class of luminous X-ray binaries discovered with the X-ray telescopes of the Einstein and ROSAT satellites and extensively studied in the optical with ground based telescopes, in the UV with IUE and HST and in X-rays with ROSAT, Beppo-SAX and ASCA (cf. Kahabka & van den Heuvel 1997, van Teeseling 1997). The luminosities derived for a first sample of supersoft sources studied with moderate resolution X-ray spectroscopy (using Beppo-SAX LECS and ASCA SIS detectors, Parmar et al. 1997, Ebisawa et al. 1997) have been predicted to follow Iben’s stability line (Iben 1982), i.e. the location in the Hertzsprung-Russell diagram which separates the plateau phase from the cooling phase. This is not unreasonable as any system experiencing steady-state accretion, i.e. accretion at a rate equalling about the nuclear burning rate will be found close to the stability line. If the accretion rate exceeds this limit then the white dwarf gets bloated and disappears in X-rays. If the accretion rate falls below this limit the white dwarf envelope cools, the luminosity as well as the temperature ceases and the source enters unstable recurrent nuclear burning. From the population synthesis calculations of Yungelson (1996) follows that there exit for the Milky Way a few sources at any epoch which are more massive than 1.2 MQ. They are expected to be extremely X-ray bright and may be standard candles (cf. Table 1 and Figure 1 for the brightest known supersoft sources per galaxy Milky Way to NGC 55). Their spectral distribution is expected to be similar to that of the extremely hot galactic source RXJ0925.7-4758 (it peaks at 1 keV and the flux is distributed from 0.5 to 2 keV, see Figure 2 for the ASCA spectrum of RX J0925.7-4758 (and CAL 87) as derived by Ebisawa et al. 1997).

We discuss how soft X-ray transients exhibit light curves associated with two accretion-disc instabilities that are well known to operate in cataclysmic variables. A thermal instability that is due to hydrogen ionization leads to the transient nature but is modified by X-ray irradiation of the disc. Growth of the disc between the ensuing outbursts leads to a 3:1 commensurability instability at the outer edge of the disc that drives superoutbursts and produces superhumps in the lightcurve if the mass ratio is sufficiently small. Superhumps are observed only in the short period SU UMa CVs but black hole primaries allow SXTs to exhibit superoutbursts and superhumps at much larger periods. We point out similarities between SXT superhump shapes and those of the small class of ER UMa CVs, The similarity between these systems stems from the fact that the mass-transfer rates are almost large enough to stabilize the disc against the thermal instability in both cases.

Exept Geminga there could be other gamma ray pulsars with no radioemission, which are exhibited in EGRET observations as ordinary point-like sources [6]. Determination of pulsations in a hard gamma ray source is complicated by rareness of arriving quanta δt ≫ P, and their small total number. When the value of the period is known from other observations (radio or X-ray), timing analysis gives the possibility to find this periodicity also in a gamma region [1].