Stellar Evolution theory is based upon well understood physics and provides clear predictions as to how a Colour-Magnitude Diagram (CMD) will change due to effects of age and metallicity. The theory has been tested by looking at nearby coeval star clusters. The power of applying CMD analysis to galaxies has been demonstrated in studies of the Carina dSph (Smecker-Hane et al. 1996). In Carina the observation of separate, distinct Main Sequence (MS) Turnoffs has forced us to believe that this small, nearby companion of our Galaxy has had a very complex star formation history. No similar direct evidence for “bursting” behaviour on a global scale has been seen indisputably in larger systems. Partly this is due to the greater distances of larger systems, but also to the complications in distinguishing old star formation events (> 1 Gyr old) in systems which are currently forming stars. Where we lack MS turnoffs we have to resort to statistical modeling of the CMD. This has been applied using a a number of different approaches, but all generally based on Monte-Carlo techniques (e.g. Tosi et al. 1992; Bertelli et al. 1992; Tolstoy &; Saha 1996). However, even using these more sophisticated analysis techniques, it is difficult to find unique solutions. This is mostly due to the age-metallicity degeneracy on the Red Giant Branch (RGB). The RGB is usually the most populated, easiest to observe phase of stellar evolution. The Carina CMD reveals the dangers of blindly interpreting the RGB, because from the RGB alone it is impossible to extract the information revealed by the MS Turnoffs.

In this paper a survey of three star maps produced in Korea in the mid-18th century as the results of interaction with the Jesuits in Beijing is briefly outlined. The first of these is the Honchŏn Jŏndo (abbreviated to HJ), a wood-cut print. The other two are large screen star maps, each consisting of 8 panels of a folding screen, called Screen Star Map Type 1 (abbreviated to SSM1) and Screen Star Map Type 2 (abbreviated to SSM2). On each of these three star maps there are detailed explanatory texts, which provide information on the transmission of wetern astronomy to Korea by the Royal astronomers.

The construction of a new museum of astronomy is planned by the present author in Yecheon Prefecture (λ = 128°28’ E, (ϕ> = 36°39’ N), Korea, with the openning date set in October, 1999. The aims of the museum directed in three area: (1) to exhibit astronomical works available in Korea, China, Japan and other regions of the Far East; (2) to serve the publics with written material for the study of history of Oriental astronomy; and (3) to operate a 40-cm reflecting telescope for researches of both professionals and amateur astronomers. A long-term project of the reconstruction of King Sejong’s instruments, which were made in the 15th century in the Kyongbok Palace, Seoul, is also an important subject of this museum.

The results of an investigation of the evolutionary status of fifteen gas-rich, low surface brightness dwarf galaxies (LSBDGs) are presented. LSBDGs are defined by unusually high values of MH/LB and the presence of extended HI envelopes. At both the present epoch and the past, the star formation process appears to be inefficient: the LSBDGs are underluminous for their HI mass and very little active star formation is currently observed. Analysis of global optical colors and elemental enrichments indicate that these objects are not “young” systems; rather, star formation has been occurring for several Gyr. One clue to the star formation history of these objects is that the global gas density is significantly lower than the Toomre instability criterion throughout the gas disk. Local peaks in the HI surface density, however, approach the instability criterion and are correlated with sites of active star formation. Thus, while star formation appears to be inhibited globally, the local gas distribution plays a crucial role in regulating the star formation activity in these low mass galaxies.

The M81 group is one of the nearest groups of galaxies, but its properties are quite different from those of the Local Group. It has therefore provided a different environment for the evolution of its member galaxies. We have carried out a CCD survey of the M81 group to search for analogs to Local Group dwarf elliptical (dE) galaxies. All the M81 dwarfs previously identified in photographic surveys were recovered and we also discovered several new systems whose surface brightnesses fall within the range found for Local Group dE’s.

We have obtained HST WFPC2 images through the F555W and F814W filters of two M81 group dE’s: BK5N and a new system, designated F8D1. The resulting color-magnitude diagrams show the upper two magnitudes of the red giant branch. The I magnitudes of the red giant branch tip in both galaxies yield distances that are consistent with membership in the M81 group. Surface brightness and total magnitude measurements indicate that BK5N and F8D1 have similar central surface brightness (24.5 and 25.4 mag arcsec-2 in V, respectively), but F8D1 is larger length scale results in it being 3 magnitudes more luminous than BK5N. BK5N lies on the relation between central surface brightness and absolute magnitude defined by Local Group dwarf ellipticals, but F8D1 does not. F8D1 is more luminous for its central surface brightness than the relation predicts, similar to the large low surface brightness dwarf galaxies found in, for example, Virgo. The mean color of the giant branch is used to establish the mean abundance of each galaxy. F8D1, the more luminous galaxy, is significantly more metal rich ([Fe/H] ≈ -1.0) than BK5N ([Fe/H] ≈ -1.7). Both BK5N and F8D1 lie on the relation between absolute magnitude and metal abundance defined by Local Group dwarf ellipticals. However, as regards the relation between central surface brightness and metal abundance, BK5N again follows the Local Group dwarfs, while F8D1 deviates significantly from this relation. This suggests that the total amount of luminous matter is more fundamental in controlling metal enrichment than the surface density of luminous matter. We have also used the color width of the giant branch compared with the photometric errors to establish abundance ranges in both galaxies, the sizes of which are comparable to those in Local Group dE’s.

The following is a summary of recent research which I have undertaken on the eclipse records in the Koryo-sa. This work is based on a careful examination of the astrological treatise of the Koryo-sa. I have compared each of the many solar and lunar eclipse accounts with the results of computation and based deductions on these comparisons.

The celestial map of the Chunyou stone inscription in Suzhou and that contained in the Xin yixiang fayao (), both belonging to the Song () Dynasty, are among the oldest of the extant celestial maps in China. The former has a circular form, and the latter is in two forms, circular and rectangular. I have been wondering which projection methods were used in these star maps, or rather, whether they were ever drawn accurately enough for us to be able to discuss their projection methods. While the stone inscription in Suzhou remains original without any change, we are not sure to which extent the star map in the Xin yixiang fayao maintains its original form, because the text underwent frequent reimpressions.

In the Local Group few Hɪɪ regions exhibit nebular Heɪɪ λ4686 emission, indicative of unusually high excitation. Approximately eight such nebulae are known, all located in low metallicity environments (IC 1613, SMC, LMC) except the Galactic ring nebula G2.4+1.4 (Esteban et al. 1992). The best studied case is the nebula S 3 surrounding the WO3 star DR 1 (Garnett et al. 1991, Kingsburgh &: Barlow 1995). Except for two cases (N 44C, N159 F; Stasińska et al. 1986, Pakull & Angebault 1986) the nebulae are asociated with early WN (cf. Niemela et al. 1991) and WO stars.

So far approximately 50 to 60 extragalactic Hɪɪ regions showing nebular Heɪɪ λ4686 are known (Campbell et al. 1986, Izotov et al. 1994, 1997a). Most of them are found in H II galaxies, BCDs and related objects from low metallicity samples used for determinations of the primordial helium abundance. The most prominent case is the low metallicity (Z) record holder I Zw 18. He II emission is typically on the order of 1-5 % of Hβ.

Different ionization mechanisms (photoionization by hot stars, shock excitation, photoionization by X-rays) have been put forward to explain the required hard spectrum (Garnett et al. 1991).

The first quantitative approach to address this problem are the evolutionary synthesis models of Schaerer (1996) and Schaerer & Vacca (1997), which include well tested evolutionary tracks and recent spherically expanding non-LTE atmosphere models appropriate for WR and O stars.

Diffraction limited near-infrared H-band (1.6 μm) NICMOS HST images are scheduled to be obtained in mid-October 1997 of the young cluster NGC 2070 (age 3.5 Myr) in the 30 Dor giant HII region in the LMC. The aim is to search for the low-mass (M < 2 Mʘ) low-luminosity, red pre-Main Sequence stellar population and to establish the H-band infrared luminosity function. With the NICMOS we can now determine whether the IMF in this prototypical extragalactic starburst cluster is deficient in subsolar low-mass stars or not. The best ground-based data can sample only M > 2 Mʘ. In principle, NICMOS in the H-band (F160W) is sensitive enough to reach a magnitude of ~ 23.5 in a relatively short integration time, which indeed corresponds to the fantastic possibility to detect young stellar objects with masses near the hydrogen burning limit (M=0.1 Mʘ) according to pre-Main Sequence evolutionary models. Even if we could reach only H = 22.5 (i.e. M=0.4 Mʘ), our observations will still go a long way in directly answering, by star counts, whether the IMF in starburst galaxies is low-mass deficient or not, with all the corresponding far-reaching implications.

The observations would also tell us whether the 30 Dor cluster can be regarded as a prototype young globular cluster. This possibility would be ruled out, if we found NGC 2070 to be low-mass deficient, because old globular clusters do have a rich population of low-mass stars.

This study was originally motivated from the discussion of the obliquity of the ecliptic, e, in the work of Needham (1959) and his collaborators, and the article, “An 8-th Century Meridian Line,” by Beer et al. (1961). A search in the historical records yields values of e in addition to the published values in the literatures.

We use a sample of 45 low-metallicity H II regions to determine the primordial helium abundance Yp. We have carefully investigated the physical effects which may make the He I line intensities deviate from their recombination values such as collisional and fluorescent enhancements, underlying He I stellar absorption and absorption by Galactic interstellar Na, I. By extrapolating the Y vs. O/H linear regression to O/H = 0, we obtain Yp = 0.245±0.002. Our Yp gives 0.06±0.01.

In this paper, I would like to discuss some topics about the Vedāṅga astronomy, which is a kind of ancient Indian astronomy.

The Vedāṅga (limb of the Veda) is a class of works regarded as auxiliary to the Veda. It consists of six divisions, one of which is astronomy (jyotiŢa).

Because of their low gravitational energy, low-mass galaxies are seriously affected by energetical processes in their interstellar medium, such as supernova explosions, or by gravitational perturbations, e.g., by neighbouring galaxies. This can reasonably explain their variety of morphological types. If the evolutionary timescales of galaxies are predominantly determined by internal processes, the multi-phase character as well as star-gas interactions and phase transitions have to be taken into account. For this purpose we have developed a numerical treatment of the dynamical behaviour of gas and stars, which also accounts for the metal dependence of some processes and which can trace the chemical evolution for different elements. This so-called chemodynamical treatment is described in detail in Theis et al. (1992) and Samland et al. (1997). It considers three stellar components and devides the gas into clouds (CM, with a mass spectrum) and a hot intercloud medium (ICM). Since the element enhancement of the interstellar medium is produced by different processes with different lifetimes of their progenitors, O, Fe, and N are used as tracer elements to represent supernovae type II (SNell), type la (SNela), and planetary nebulae (PNe) contributions. While supernovae form the ICM, PNe only attribute to the CM so that only mixing effects of both gas phases can alter abundance ratios.

Due to limited computer capacities the first chemodynamical simulations of dwarf galaxies could be performed only one-dimensionally so far (see e.g., Hensler et al. 1993, 1998). The recently developed two-dimensional chemodynamical code CoDEx (Samland 1994) was first applied to massive disk galaxies and produced models of which a particular one could represent various chemical and structural observations of the Milky Way with striking agreement (Samland et al. 1997).

Although the methods of plane trigonometry became the cornerstone of classical Indian mathematical astronomy, the corresponding techniques for exact solution of triangles on the sphere’s surface seem never to have been independently developed within this tradition. Numerous rules nevertheless appear in Sanskrit texts for finding the great-circle arcs representing various astronomical quantities; these were presumably derived not by spherics per se but from plane triangles inside the sphere or from analemmatic projections, and were supplemented by approximate formulas assuming small spherical triangles to be plane.

All 13 Shang dynasty oracle bone eclipse records have been uniquely matched to 6 solar and 7 lunar eclipses in the 14-12th centuries B.C. The King Zhong Kang 5th year autumnal (Oct. 16, 1876 B.C.) and King Yu 3rd year “double sunset” (Sept. 24, 1912 B.C.) eclipses confirm the accuracy of the revised Bamboo Annals Xia dynasty chronology (Nivision and Pang, Early China 15, 1990, 87). The eclipse dates are plotted against the number of generations before 841 B.C. (earliest accurate date), the respective kings ruled. The curve of benefit has both the strengths of verified royal genealogy – continuity – and eclipse dating – accuracy. It is 99% accurate, and can be confidently used as a foundation for building a detailed absolute chronology for the Xia, Shang and Zhou dynasties, an important project in China’s new 5-Year Plan (Song, Sci. Tech. Daily, May 17, 1996; Newsweek, July 7, 1997).

The life and evolution of galaxies are dramatically affected by environmental effects. Interactions with the intergalactic medium and collisions with companions cause major perturbations in the morphology and contents of galaxies: in particular stars and gas clouds may be gravitationally pulled out from their parent galaxies during tidal encounters, forming rings, tails and bridges. This debris of collisions lies at the origin of a new generation of small galaxies, the so-called “tidal dwarf galaxies” (hereafter TDGs). Such an exotic way of forming galaxies was put forward by Schweizer (1978) and by Mirabel et al. (1992), who clearly observed the genesis of a star-forming object, out of material tidally expelled from the interacting system NGC 4038/39 (“The Antennae”). Recent studies, based on optical and HI observations, have shown that TDGs actually form a class of “recycled” objects with some properties similar to the more classical dwarf irregulars (dIrr) and blue compact dwarf galaxies (BCDs).

In November of 1730 the Portuguese astronomer Pedro da Silva arrived in Jayasiṃha’s court bearing, among other books, a copy of the second edition of Philippe de La Hire’s Tabulae Astro-nomicae, published in Paris in 1727. The choice of this text as the representative of contemporary European astronomy being sent to the Maharaja was apparently due to the fact that de La Hire, finding fault with the Rudolphine Tables, whose alleged errors he attributes to Kepler’s hypotheses, claims: Quamobrem id statui Tabulas meas nulli hypothesi, sed observationibus tantummodò superstruere, nulla cuius vis Systematis habita ratione. This abjuring of adhesion to an “heretical” astronomy must have pleased the Jesuits who chose the book. This aspect of the Tabulae Astronomicae (though in fact de La Hire does adhere to an astronomical hypothesis, the heliocentric) appealed also to Jospeh Dubois, who wrote at the beginning of the Jayapura copy on September 1732: Tabulae Astronomicae in quibus Solis, Lunae, reliquorum planetarum motus ex ipsis observationibus nulla adhibita hypotesi traduntur. This same propaganda explains the title, Drkpaksasâranï, given to the adaption of the Tabulae Astronomicae written in Sanskrit verse by Kevalarama, Jayasimha’s jyotisarãja, in or after 1733 when the new city of Jayapura, to which he refers, began to be occupied, and the astonishing fact that Kevalrarãma nowhere in this work mentions the heliocentric theory though the computations that he prescribes are based upon it.

Dwarf galaxies at high redshifts are important to study for a variety of reasons. By dwarf, we mean galaxies with low-mass, though galaxies with low-luminosities or small sizes are also commonly referred to as dwarfs. Several groups have suggested that such galaxies may be major contributors to faint blue galaxies, whose nature remains unclear. Dwarfs are viable candidates for faint blue galaxies if many undergo strong bursts of star-formation at redshifts z ~ 1 (Babul and Ferguson 1996) or even lower redshifts z ~ 0.3 (Cowie, Songaila, and Hu 1991; Broadhurst et al. 1988) and fade or disappear by today; if they have a much steeper luminosity function (Driver et al. 1994) than generally adopted in faint galaxy models; or if they represent small pre-merger fragments of larger galaxies today (Guiderdoni and Rocca-Volmerange 1990; Broadhurst, Ellis, and Glazebrook 1992), as might be expected in standard cold dark matter models with hierarchical galaxy formation.

The Period from 1858 to 1947 is known as the British Period of Indian History. After the fall of Mughal empire, when the first war of independence against British colonisers failed in 1857, and the East India Company’s Government was transferred to the British Crown in 1858. However only in 1910, a Department of Education was established by the (British) Govt, of India and in the following decades modern universities were established in various important Indian towns, wherein Western / European type education and training with English as medium of instruction were imparted. However more than a century before, Indian scholar’s came into contact with the scholars – administrators of East India Company, either through employment or social interaction. Thereby, Indians became acquainted with the scientific (also technological) advances in Europe. A few of them visited England and other European countries, Portugal, Prance etc. already in the last quarter of 18th century, in order to experience and to learn firsthand the European sciences.

We study the global properties of 51 compact field galaxies with redshifts z ~ 0.2 - 1.3 and apparent magnitudes I814 < 23.74 in the flanking fields of the Hubble Deep Field. All these galaxies have angular half-light radii re < 0.5 arcsec. Keck spectra covering ~4000-9000 Å, combined with HST І814 images and Keck V-band images, were used to derive redshifts, V606 - I814 colors, absolute blue magnitudes (MB), linear half-light radii (Re ), blue average surface brightnesses within Re (SBe ), velocity widths (σ), virial masses (M), mass-to-light ratios (M/L), excitations (O[III]/Hβ), and star formation rates (SFR). The results of this study can be summarized as follows:

1. (i): Only 12% of the 51 compact galaxies have absorption-line dominated spectra, while 88% show strong, narrow emission lines, similar to the so-called CNELGs (e.g., Koo, this volume).

2. (ii): Despite being very luminous (i.e., LB ~ L*; see figure la), compact emission-line galaxies are low-mass stellar sytems (i.e., M ≤ 1010 Mʘ, typically; see figure lb).

3. (iii): Roughly 60% of the compact emission-line galaxies have colors, sizes, surface brightnesses, luminosities, velocity widths, excitations, star formation rates, and mass-to-light ratios characteristic of young, star-forming HII galaxies (see figures 1 and 2). The remaining 40% form a more heterogeneous class of evolved starbursts, similar to local disk starburst galaxies.

4. (iv): Without additional star formation, galaxy evolution models predict that HII-like distant compacts will fade to resemble today’s spheroidal galaxies such as NGC 205 (Koo, this volume).