The 2011 Nobel prize in physics has been awarded to S. Perlmutter, A. Riess and B. Schmidt for their path breaking discovery that the rate of expansion of the universe is increasing with time. The trio used Type Ia supernovae (SNe Ia) as standard candles to estimate their luminosity-distances. To appreciate some of the far reaching implications of their work, I have provided an elementary exposition of general theory of relativity, accelerated expansion of the universe, luminosity-distance, SNe Ia and the cosmological constant problem.

GeographicLib is a small set of C++ classes for performing conversions between geographic, UTM, UPS, MGRS, geocentric, and local cartesian coordinates, for gravity (e.g., EGM2008), geoid height, and geomagnetic field (e.g., WMM2010) calculations, and for solving geodesic problems. It is a suitable replacement for the core functionality provided by geotrans. The library is licensed under the MIT/X11 License; see LICENSE.txt for the terms.

The argparse module was added to Python 2.7 as a replacement for optparse. The implementation of argparse supports features that would not have been easy to add to optparse, and that would have required backwards-incompatible API changes, so a new module was brought into the library instead. optparse is still supported, but is not likely to receive new features.

The ATLAS3D Project (Cappellari et al. 2011) combines a multi-wavelength survey of a complete sample of 260 early-type galaxies within the local (42Mpc) volume (1.16×105 Mpc3) with numerical simulations and semi-analytic modeling of galaxy formation. This project aims to quantify the global stellar kinematics and dynamics of a statistically significant sample of objects to characterize the class of early-type galaxies, and relate this to their formation and evolution. Combining the stellar populations diagnostics from the multi-wavelength coverage, the ATLAS3D Project will derive the star formation history probing the mass-assembly epochs and timescales. In addition, the project will characterise the different phases of the interstellar medium linking the kinematics of molecular, atomic and ionised gas with the dynamical structure, star formation and environment of the host galaxies.

Shape is a morpho-kinematic modeling and reconstruction tool for astrophysical objects. With this software you can quickly construct 3D model structures and directly compare them with data in order to assist in the interpretation of observations. From such a 3D structure model with a model velocity field and emission properties, it generates images and position-velocity (pv) diagrams, channel maps, light echoes, light curves and one dimensional spectral line shape, to mention a few. Wavelength dependent radiation transfer for line emission and scattering on dust is also possible.

PGFPlots draws high--quality function plots in normal or logarithmic scaling with a user-friendly interface directly in TeX. The user supplies axis labels, legend entries and the plot coordinates for one or more plots and PGFPlots applies axis scaling, computes any logarithms and axis ticks and draws the plots. It supports line plots, scatter plots, piecewise constant plots, bar plots, area plots, mesh-- and surface plots, patch plots, contour plots, quiver plots, histogram plots, polar axes, ternary diagrams, smith charts and some more.

Now in its fourth edition, this highly regarded book is ideal for those who wish to solve a variety of practical and recreational problems in astronomy using a scientific calculator or spreadsheet. Updated and extended, this new edition shows you how to use spreadsheets to predict, with greater accuracy, solar and lunar eclipses, the positions of the planets, and the times of sunrise and sunset. Suitable for worldwide use, this handbook covers orbits, transformations and general celestial phenomena, and is essential for anyone wanting to make astronomical calculations for themselves. With clear, easy-to-follow instructions for use with a pocket calculator, shown alongside worked examples, it can be enjoyed by anyone interested in astronomy, and will be a useful tool for software writers and students studying introductory astronomy. High-precision spreadsheet methods for greater accuracy are available at www.cambridge.org/practicalastronomy.

Processing is an open source programming language and environment for people who want to create images, animations, and interactions. Initially developed to serve as a software sketchbook and to teach fundamentals of computer programming within a visual context, Processing also has evolved into a tool for generating finished professional work. Today, there are tens of thousands of students, artists, designers, researchers, and hobbyists who use Processing for learning, prototyping, and production.

Random numbers have a peculiar power, even when they are only pseudo- or quasirandom

This file contains Galactic stars known or suspected to be variable.
It lists all stars that have an entry in the AAVSO International
Variable Star Index (VSX; http://www.aavso.org/vsx).

The database consisted initially of the General Catalogue of Variable
Stars (GCVS) and the New Catalogue of Suspected Variables (NSV) and
was then supplemented with a large number of variable star catalogues,
as well as individual variable star discoveries or variables found in
the literature. Effort has also been invested to update the entries
with the latest information regarding position, type and period and to
remove duplicates. The VSX database is being continually updated and
maintained.

For historical reasons some objects outside of the Galaxy have been
included.

The AAVSO is an international non-profit organization of variable star observers whose mission is:

to observe and analyze variable stars
to collect and archive observations for worldwide access
to forge strong collaborations between amateur and professional astronomers
to promote scientific research and education using variable star data.

The GCVS is the only reference source on all known variable stars.
This version contains the electronically-readable version as
distributed by the Sternberg Astronomical Institute and Institute of
Astronomy (Russian Acad.Sci.), Moscow. It includes the catalog of
variable stars, updated and completed with the Name-Lists of Variables
Stars Nos. 67-79, the NSV (New catalog of Suspected Variable stars)
and Supplement to the NSV stars, and a catalog of extragalactic
variables. A cross-index makes possible to find out identifications
between the GCVS and the NSV catalogue.

Auto Complete Mode is the most intelligent auto-completion extension for GNU Emacs. Auto Complete Mode renews an old completion interface and provides an environment that makes users could be more concentrate on their own works.

Fv is the easy to use graphical program for viewing and editing any FITS format image or table. The Fv software is small, completely self-contained and ready to run on

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If you have the ISBN (International Standard Book Number) for a publication, you can generate a citation for it in the BibTeX format.

PyEphem provides scientific-grade astronomical computations for the Python programming language. Given a date and location on the Earth’s surface, it can compute the positions of the Sun and Moon, of the planets and their moons, and of any asteroids, comets, or earth satellites whose orbital elements the user can provide. Additional functions are provided to compute the angular separation between two objects in the sky, to determine the constellation in which an object lies, and to find the times at which an object rises, transits, and sets on a particular day.

Overwhelming collection of old star maps and celestial atlasses.

The caption package provides many ways to customise the captions in floating environments like figure and table, and cooperates with many other packages. Facilities include rotating captions, sideways captions, continued captions (for tables or figures that come in several parts). A list of compatibility notes, for other packages, is provided in the documentation.

On these sites there exist already introductions to Gnuplot, but I want to do it in a slightly different way that concentrates on the way I’m using Gnuplot.
And this way means, that I will present no introduction to the interactive Gnuplot prompt, but will start directly with writing some text files. These files can then be executed by Gnuplot.

How was the world created? People have asked this ever since they could ask anything, and answers have come from all sides: from religion, tradition, philosophy, mysticism... and science. While this does not seem like a problem amenable to scientific measurement, it has led scientists to come up with fascinating ideas and observations: the Big Bang, the concept of inflation, the fact that most of the world is made up of dark matter and dark energy which we can not perceive, and more.
Of course scientists cannot claim to know the definitive truth. But we can approach the question from a scientific viewpoint and see what we find out. How do we do that? First, we look to the data. Thanks to modern technology, we have much more information than did people of previous ages who asked the same question. Then we can use scientific methods and techniques to analyze the data, organize them in a coherent way and try and extract an answer. This process and its main findings will be described in the article.

This paper presents a hands-on introduction to the medieval astrolabe, based around a working model which can be constructed from photocopies of the supplied figures. As well as describing how to assemble the model, I also provide a brief explanation of how each of its various parts might be used. The printed version of this paper includes only the parts needed to build a single model prepared for use at latitudes around 52{deg}N, but an accompanying electronic file archive includes equivalent images which can be used to build models prepared for use at any other latitude. The vector graphics scripts used to generate the models are also available for download, allowing customised astrolabes to be made.

the opening paragraph of the article Mindless Statistics by Gerd Gigerenzer

A blog about pencils...

PyAST is a collection of modules that allows the facilities of the Starlink AST library to be used within Python (version 2.7 or later) scripts.
The AST library provides a comprehensive range of facilities for attaching world coordinate systems to astronomical data, for retrieving and interpreting that information and for generating graphical output based on it. AST is written in ANSI C but has wrappers for various other languages, including Fortran, Java, Perl, and now Python.

The Revista Mexicana de Astronomia y Astrofisica, founded in 1974, publishes original research papers in all branches of Astronomy, Astrophysics and closely related fields. Two numbers per year are issued and are distributed free of charge to all institutions engaged in the fields covered by the RevMexAA.

The circumgalactic medium (CGM) is fed by galaxy outflows and accretion of intergalactic gas, but its mass, heavy element enrichment, and relation to galaxy properties are poorly constrained by observations. In a survey of the outskirts of 42 galaxies with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope, we detected ubiquitous, large (150-kiloparsec) halos of ionized oxygen surrounding star-forming galaxies; we found much less ionized oxygen around galaxies with little or no star formation. This ionized CGM contains a substantial mass of heavy elements and gas, perhaps far exceeding the reservoirs of gas in the galaxies themselves. Our data indicate that it is a basic component of nearly all star-forming galaxies that is removed or transformed during the quenching of star formation and the transition to passive evolution.

Armadillo is an open-source C++ linear algebra library (matrix maths) aiming towards a good balance between speed and ease of use. Integer, floating point and complex numbers are supported, as well as a subset of trigonometric and statistics functions.

Publishing and knowledge production in academia can be significantly improved if aspects of cooperative models developed in software and networking communities are adopted. Open Access movement does that partially, by focusing on the openness of the final result. The most important attributes of the development of the Internet, the Web and their communication-cooperation tools is openness of the entire process of production. The novelty that can take many forms is in the organizational structures, decision making and cooperation. This article argues that journals adopting a form of open-process approach could benefit by increased quality of submissions and publications, faster and more responsive pace of research and by attracting more risk taking and innovative authors. Through clearer structure and visibility of tasks, equally important could be possible internal benefits for journals: recognition of the most important workers and decision making in their hands, easier and improved project management, attracting new volunteers and reducing the impact of counter-productive participants. If these changes were implemented well, such open-process journals would gain readership and reputation. Open-process academic publishing can take procedurally and technologically complex forms. A simple transition model is suggested: how to start with an email list and right cultural safeguards.

To our best knowledge, there are no problem books on cosmology yet, that would include its spectacular recent achievements. We believe there is a strong need for such now, when cosmology is swiftly becoming a strict and vast science, and the book would be extremely useful for the youth pouring in this area of research. Indeed, the only way to rise over the popular level in any science is to master its alphabet, that is, to learn to solve problems.
Of course, most of modern textbooks on cosmology include problems. However, a reader, exhausted by high theory, may often be thwarted by the lack of time and strength to solve them. Might it be worth sometimes to change the tactics and just throw those who wish to learn to swim into the water?
The proposed problems constitute our contribution to this cause. There are over 1000 problems, divided into 14 chapters, covering topics from the dynamics of the expanding Universe and CMB to cosmology beyond the Lambda-CDM model and holography. We intend to publish their solutions in later editions. The reader, however, is encouraged to look for answers independently, even though - or especially so because - the problems range from easy to not quite and from elements of scientific folklore already to those with answers not quite settled.

MEMORIE della Società Astronomica Italiana is a professional quarterly journal devoted exclusively to the publication of Conference Proceedings and invited review papers. MEMORIE publishes only papers written in English. The journal is distributed to all members of the SAIt and to over one hundred subscribers abroad, including the main astronomical institutions. Since 1986 more than 30 conferences have been published.

Cleans up, regularizes, and reformats the text of Python scripts.

This page explains emacs library system. For example, what's the difference between library, package, features? And what's the difference between {load-file, load, require, autoload}?

KDiff3 is a program that

* compares or merges two or three text input files or directories,
* shows the differences line by line and character by character (!),
* provides an automatic merge-facility and
* an integrated editor for comfortable solving of merge-conflicts,
* supports Unicode, UTF-8 and other codecs, autodetection via byte-order-mark "BOM"
* supports KIO on KDE (allows accessing ftp, sftp, fish, smb etc.),

Astro-WISE stands for Astronomical Wide-field Imaging System for Europe. Astro-WISE is an environment consisting of hardware and software which is federated over about a dozen institutes all over Europe. It has been developed to scientifically exploit the ever increasing avalanche of data produced by science experiments. We call such an environment an information system. As the name suggests, Astro-WISE started out as a system geared towards astronomy, but is now also being used for projects outside astronomy. Astro-WISE is an all-in-one system: it allows a scientist to archive raw data, calibrate data, perform post-calibration scientific analysis and archive all results in one environment. The system architecture links together all these commonly discrete steps in data analysis.

This new NumPy book provides an easy start to NumPy for those who want to churn numbers in Python programming language, whether you don't have much programming background or you are switching from your favorite language. The author of the book uses quite a friendly tone throughout the book. Most of the important aspects of NumPy is well covered with well explained examples. The examples provided are step by step explained, starting from the basic array/matrix creation to more complex tasks like signal analysis and linear algebra related calculations.
[...]

In my research, I often generate a sequence of images from either my experiment or from a simulation that I want to put together into a movie. Since I use linux, I wanted to do this using free software in linux, and I wanted to be able to play the movie in linux. This webpage outlines what I've learned about how to do this in linux using mencoder or ffmpeg to create high quality files that are well compressed and the play well under all operating systems.

GNU Data Language (GDL) is a free/libre/open source incremental compiler compatible with IDL and to some extent with PV-WAVE. Together with its library routines it serves as a tool for data analysis and visualization in such disciplines as astronomy, geosciences and medical imaging. GDL is free software licensed under the GPL. GDL is developed by an international team of volunteers led by Marc Schellens - the project's founder

This command acts as a standard Unix filter: it takes a list of FITS file names in input and outputs their headers to stdout. Convenient to browse headers in directories. See fitsort to classify data from a list of FITS headers produced by dfits.

HPC Techreport
A brief introduction to Python (for scientific computing)

We have prepared a comprehensive critically evaluated compilation of the most accurate wavelength measurements for classified lines of neutral neon (Ne I) in its natural isotopic abundance. Data from 19 sources spanning the region 256 Å to 54 931 Å are included. Based on this line list we have derived optimized values for the energy levels of neutral neon. Tabular data for 1595 classified lines and 374 energy levels are provided. In addition to the observed wavelengths, we present revised wavelengths calculated from the optimized energy levels for all lines that have been previously recommended for use as secondary wavelength standards. © 2005 by the U.S. Secretary of Commerce on behalf of the United States. All rights reserved.

This handbook is designed to provide a selection of the most important and frequently used atomic spectroscopic data in an easily accessible format. The compilation includes data for the neutral and singly-ionized atoms of all elements hydrogen through einsteinium (Z = 1-99). The wavelengths, intensities, and spectrum assignments are given in a table for each element, and the data for the approximately 12,000 lines of all elements are also collected into a single table, sorted by wavelength (a "finding list").

The general idea is that we meet up on Twitter at a prearranged day and time and discuss an interesting piece of astronomy research. This will generally take the form of an academic paper, but we could also include some articles too. Everyone’s welcome to participate, whether you’re an expert in the topic or not – as long as you’ve read the paper. We hope that the real-time aspect of Twitter will make it a suitable platform for an online discussion. Check out the Next Meeting page for information about the next meeting, including the paper that we will be discussing.

Im Jahr 1992 gründete sich innerhalb der Astronomischen Gesellschaft ein Arbeitskreis Astronomiegeschichte.
Im Auftrag dieses Arbeitskreises geben nun seit 1998 die bekannten Astronomiehistoriker Wolfgang R. Dick und Jürgen Hamel die Buchreihe Acta Historica Astronomiae heraus (ISSN 1422-8521)
Im Vorwort zum ersten Band dieser Reihe schreiben Dick und Hamel:

"Besonders nach der Einstellung der Zeitschrift Die Sterne fehlt es im deutschsprachigen Raum an Möglichkeiten zur Publikation wissenschaftlicher Aufsätze auf dem Gebiet der Geschichte der Astronomie. In dem nunmehr mit dem ersten Band vorliegenden Acta Historica Astronomiae sollen Bücher und Broschüren verschiedenster Art publiziert werden: Monographien, Sammel- und Tagungsbände, Editionen von Handschriften, Bibliographien und Nachlassverzeichnisse sowie astronomiehistorische Dissertationen. Denkbar sind auch Nachdrucke interessanter historischer Werke."

The Great Observatories Origins Deep Survey (GOODS) is a public, multiwavelength survey which originally covered two 150 square arcmin fields, centered around the HDF-N (Hubble Deep Field North) and the CDF-S (Chandra Deep Field South). It is a coordinated effort to combine the deepest survey data over the widest wavelength range (from X-ray through radio) from NASA’s Great Observatories (HST, Chandra, Sptizer), ESA’s XMM-Newton, and the largest ground-based observatories, namely ESO-VLT, Keck, Gemini in the optical/nearIR region, VLA in the radio, etc. Observations were designed to promote major advances in following primary science areas:

Vereiningung für Jugendarbeit in der Astronomie e.V.

Las Cumbres Observatory Global Telescope Network is a private operating foundation, building a global network of telescopes for professional research and citizen investigations

The Special Astrophysical Observatory (SAO) was founded in 1966. At present it is the largest Russian astronomical center for ground-based observations of objects in the Universe.

Astrobites is a daily literature journal summarizing new astrophysical research posted to astroph. Astrobites is written by graduate students for undergraduates. Read more about our goals.

The PASEO group aims at the development of new data analysis tools in the space imaging domain. Probabilistic approaches are used to model complex datasets (multispectral, multiple sources), and to solve the inverse problems related to their analysis.

PASEO is currently a research group within the MIV team (LSIIT, Illkirch), in close collaboration with the CDS (Strasbourg Observatory), mainly funded by CNRS, ULP and various national and European projects.

This company offers tot their clients management, design and developments of technological projects with scientific goals, software developments and consultancy in astronomical instrumentation.

Manually labeling features in a crowed plot can be very time consuming. Functions in this module can be used to automatically place labels without the labels overlapping each other. This is useful, for example, in creating plots of spectrum with lines identified with labels.

Line Identification Plots v0.1 documentation
Line identification plots with automatic label layout

This module has functions for automatically placing labels in a plot in such a way that the labels do not overlap with each other. This is very useful, for example, in creating plots that have labels identifying features in a spectrum.

FITS Manager (FM) is a desktop application for astronomers to manage FITS files hosted in their personal computers. This toolkit is a collaboration project between Chinese Virtual Observatory (China-VO) and Virtual Observatory India (VO-India).

Dr. Hans Vehrenberg war in den 60er Jahren des letzten Jahrhunderts vielleicht der weltweit bekannteste, sicher aber erfolgreichste Astrofotograf. Mit seinen Zeiss Astrokameras erstellte er den ersten fotografischen Sternatlas, der den ganzen Himmel komplett abbildete, den Falkauer Atlas. Mit einem 120mm Zeiss Sonnefeld Astrovierlinser fotografierte er den gesamten Himmel im doppelten Maßstab ein zweites Mal, um seinen Atlas Stellarum zu erstellen. Darüber hinaus veröffentlichte Dr. Vehrenberg ein Milchstraßenmosaik, den Atlas of Selected Areas (zusammen mit den französischen Astronomen A. Brun), sein Messier-Buch und den Atlas Galaktischer Nebel (zusammen mit Dr. Neckel).

p3d is a general data-reduction tool that is intended to be used with data of fiber-fed integral field spectrographs (IFSs). This tool can be useful for people who have access to astronomical data of such an instrument. Data-reduction tasks, which are performed by p3d, convert raw data of CCD detectors into extracted spectra that can thereafter be used for scientific purposes.

Welcome to the Sloan Digital Sky Survey III Science Archive Server. The SDSS-III is a large imaging and spectroscopic survey of the Northern sky, using a 2.5m optical telescope at Apache Point Observatory in New Mexico. The SAS serves images and spectra generated by the survey to astronomers and the general public alike. Please see the main survey site for full details and documentation.

The OPERA neutrino experiment at the underground Gran Sasso Laboratory has measured the velocity of neutrinos from the CERN CNGS beam over a baseline of about 730 km with much higher accuracy than previous studies conducted with accelerator neutrinos. The measurement is based on high-statistics data taken by OPERA in the years 2009, 2010 and 2011. Dedicated upgrades of the CNGS timing system and of the OPERA detector, as well as a high precision geodesy campaign for the measurement of the neutrino baseline, allowed reaching comparable systematic and statistical accuracies. An early arrival time of CNGS muon neutrinos with respect to the one computed assuming the speed of light in vacuum of (60.7 \pm 6.9 (stat.) \pm 7.4 (sys.)) ns was measured. This anomaly corresponds to a relative difference of the muon neutrino velocity with respect to the speed of light (v-c)/c = (2.48 \pm 0.28 (stat.) \pm 0.30 (sys.)) \times 10-5.

Astro-ph discussions

This page provides links to an overview of deep fields. The focus here is on imaging surveys and we maintain two different lists: One is a manually assembled list of deep fields typically with multi-wavelength imaging and the other is an automatically generated list of all deep fields observed by HST.

Deft is an Emacs mode for quickly brows­ing, fil­ter­ing, and edit­ing di­rec­to­ries of plain text notes, in­spired by No­ta­tional Ve­loc­ity. It was de­signed for in­creased pro­duc­tiv­ity when writ­ing and tak­ing notes by mak­ing it fast and sim­ple to find the right file at the right time and by au­tomat­ing many of the usual tasks such as cre­at­ing new files and sav­ing files.

SDSS images of selected RC3 galaxies

Naively applying Hubble's law to a sufficiently distant object gives a receding velocity larger than the speed of light. By discussing a very similar situation in special relativity, we argue that Hubble's law is meaningful only for nearby objects with non-relativistic receding speeds. To support this claim, we note that in a curved spacetime manifold it is not possible to directly compare tangent vectors at different points, and thus there is no natural definition of relative velocity between two spatially separated objects in cosmology. We clarify the geometrical meaning of the Hubble's receding speed v by showing that in a Friedmann-Robertson-Walker spacetime if the four-velocity vector of a comoving object is parallel-transported along the straight line in flat comoving coordinates to the position of a second comoving object, then v/c actually becomes the rapidity of the local Lorentz transformation, which maps the fixed four-velocity vector to the transported one.

In the late 1960s British mathematician John Conway invented a virtual mathematical machine that operates on a two-dimensional array of square cell. Each cell takes two states, live and dead. The cells’ states are updated simultaneously and in discrete time. A dead cell comes to life if it has exactly three live neighbours. A live cell remains alive if two or three of its neighbours are alive, otherwise the cell dies. The Conway’s Game of Life became the most programmed solitary game and the most known cellular automaton. The book brings together results of forty years of study into computational, mathematical, physical and engineering aspects of the Game of Life cellular automata. Selected topics include phenomenology and statistical behaviour; space-time dynamics on Penrose tilling and hyperbolic spaces; generation of music; algebraic properties; modelling of financial markets; semi-quantum extensions; predicting emergence; dual-graph based analysis; fuzzy, limit behaviour and ...

We’re a group of Linux administrators that wanted a place to share bash shell scripts and Linux command tutorials with other Linux users. BashShell.net is the site we’ve chosen to index tutorials, tips and shell scripting lessons as we come across them.

PyChecker is a tool for finding bugs in python source code. It finds problems that are typically caught by a compiler for less dynamic languages, like C and C++. It is similar to lint. Because of the dynamic nature of python, some warnings may be incorrect; however, spurious warnings should be fairly infrequent.

new upcoming features in ipython 0.11

PP is a python module which provides mechanism for parallel execution of python code on SMP (systems with multiple processors or cores) and clusters (computers connected via network).

If you have astronomical imaging of the sky with celestial coordinates you do not know—or do not trust—then Astrometry.net is for you. Input an image and we'll give you back astrometric calibration meta-data, plus lists of known objects falling inside the field of view.

This program, given a source file, produces a document with syntax highlighting.

Urania’s Mirror is a boxed set of 32 constellation cards first published by Samuel Leigh of the Strand, London, in or shortly before 1825. The engraver was Sidney Hall but authorship was coyly attributed to “a lady”. Peter Hingley, librarian of the Royal Astronomical Society in London, has established that the true author was almost certainly the Reverend Richard Rouse Bloxam of Rugby (Journal of the British Astronomical Association, vol. 104, p. 238, 1994).

If you are looking for a screen-based astronomical ephemeris program with that retro look, or just want something very small and efficient, try ephem. It was written about 20 years ago in C and still compiles on just about any UNIX platform (including Linux and Mac OS X) and even VMS and Windows. The output is always 24 rows and 80 columns, just like the old glass TTYs.

Verbatim code in a framed figure box using LaTeX

The 110 galaxies, star clusters and nebulae catalogued by the comet hunter Charles Messier in the late 1700s are still the most widely observed celestial wonders in the heavens. They are the favourite targets of amateur astronomers, with such rich variety and detail that they never cease to fascinate. This book provides new and experienced observers with a fresh perspective on the Messier objects. Stephen James O'Meara has prepared a visual feast for the observer. Using the finest optical telescopes available for amateur work, superior eyepieces and the darkest site on Earth, he describes and sketches the view from the telescope as never before. There are new drawings, improved finder charts, and new astronomical data on each object, including findings from the Hubble Space Telescope. This is truly the Messier Guide for the modern age.

This page, updated monthly, will let you know some of the things that you can look out for in the night sky. It lists the phases of the Moon, where you will see the naked-eye planets and describes some of the prominent constellations in the night sky during the month