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American Association of Variable Star Observers

American Association of Variable Star Observers
Related:  Astronomy&Astrophysics

Slacker Astronomy Transform Applier As you work your way up the learning curve of CCD photometry one of the later refinements is to develop transform coefficients for your telescope/filter/CCD camera setup. There are several references from the AAVSO website on how to do this and I’ve included some of them below. Once you have your coefficients you need to apply them to your observations. This can be a confusing process and usually involves transcribing your data to various spreadsheets. I offer here an application that is meant to make that process of applying your coefficients simple, consistent and easily traceable. There is still open discussion on how exactly you should apply your coefficients. And then Lou Cohen’s article tries to explain it further and correct minor errors : Cohen, Lou. The process I have in Transformer is to take the file with your untransformed observations and have the Transformer application scan it and rewrite it with the transformed observations.

How the Sun Shines by John N. Bahcall* What makes the sun shine? How does the sun produce the vast amount of energy necessary to support life on earth? These questions challenged scientists for a hundred and fifty years, beginning in the middle of the nineteenth century. Theoretical physicists battled geologists and evolutionary biologists in a heated controversy over who had the correct answer. Why was there so much fuss about this scientific puzzle? The sun's rays are the ultimate source of almost every motion which takes place on the surface of the earth. In this essay, we shall review from an historical perspective the development of our understanding of how the sun (the nearest star) shines, beginning in the following section with the nineteenth-century controversy over the age of the sun. The Age of the Sun How old is the sun? The older the sun is, the greater the total amount of radiated solar energy. Conflicting Estimates of the Solar Age Who Was Right? What was wrong with Kelvin's analysis? F.W.

Cosmigraphics: Picturing Space Through Time in 4,000 Years of Mapping the Universe Long before Galileo pioneered the telescope, antagonizing the church and unleashing a “hummingbird effect” of innovation, humanity had been busy cataloging the heavens through millennia of imaginative speculative maps of the cosmos. We have always sought to make visible the invisible forces we long to understand, the mercy and miracle of existence, and nothing beckons to us with more intense allure than the majesty and mystery of the universe. Four millennia of that mesmerism-made-visible is what journalist, photographer, and astrovisualization scholar Michael Benson explores with great dedication and discernment in Cosmigraphics: Picturing Space Through Time (public library) — a pictorial catalog of our quest to order the cosmos and grasp our place in it, a sensemaking process defined by what Benson aptly calls our “gradually dawning, forever incomplete situational awareness.” Contemporary thought is endangered by the picture of nature drawn by science.

Home Page VPHOT VPhot is an online tool for photometric analysis. You can upload your own FITS images to VPhot or have images taken via the AAVSOnet robotic telescope network automatically sent to your VPHOT account. To use VPhot you must: Be an AAVSO member (Apply for membership.) All VPhot processing is done via a web browser. We also have an online VPHOT Forum for your questions, comments and suggestions. The main VPhot interface with some sample images loaded. The following series of video tutorials have been produced by Ken Mogul.

If A Primordial Black Hole Hits The Sun...  Astronomers have so far discovered two types of black hole: supermassive ones at the centre of galaxies and stellar-mass black holes, which form when giant stars die. But there’s no reason why black holes of any size cannot form. In fact, many astronomers think that the variations in density in the early universe would have led to the natural formation of relatively small black holes. The smallest of these ought to have evaporated by now. Various theorists have suggested that we could spot primordial black holes by phenomena such as lensing effects as they pass in front of distant stars or by the gamma ray bursts they create as they flicker out of existence. Now Michael Kesden at New York University and Shravan Hanasoge at Princeton University in New Jersey say that the effect of a primordial black hole hitting the Sun ought to be easily observable. Such an event wouldn’t be as catastrophic as it sounds. That should generate a scramble.

Time delay The Astrophysical Journal, 521:L45-L48, 1999 August 10 © 1999. The American Astronomical Society. All rights reserved. Printed in U.S.A. A Method of Mass Measurement in Black Hole Binaries using Timing and High-Resolution X-Ray Spectroscopy A. Received 1999 April 21; accepted 1999 June 10; published 1999 June 28 In X-ray binaries, several percent of the compact object luminosity is intercepted by the surface of the normal companion and reradiated through Compton reflection and the K fluorescence. line and above the K edge of neutral iron. 106 s observation by a telescope with a 1000 cm2 effective area near 6.4 keV and with a 5 eV energy resolution. Subject headings: binaries: spectroscopic; X-rays: general; X-rays: stars The existence of stellar-mass black holes in our Galaxy is almost exclusively established by measuring the mass of the compact object in several bright X-ray binaries. is unstable and should collapse to form a black hole (Rhoades & Ruffini 1974; Chitre & Hartle 1976). is 2(c

Astronomy Picture of the Day VSP The Variable Star Plotter (VSP) is the AAVSO's online chart plotting program that dynamically plots star charts for any location on the sky, or for any named object currently in the Variable Star Index (VSX). By creating charts this way, every chart utilizes the most current data available. Through the use of unique Chart IDs generated by the Variable Star Plotter, one user can plot a chart, and another user in different part of the world can plot an identical chart by simply using the same Chart ID. The Variable Star Plotter is the tool you should use to create any chart that you would like to use. By entering an object name or its coordinates on the sky, the Variable Star Plotter can produce a star chart for that object or location, and tailor it to your specific observing requirements. For detailed instructions on using VSP, consult the Help Guide. If you need further assistance, you can email us at aavso@aavso.org. WHAT IS THE NAME, DESIGNATION, OR AUID OF THE OBJECT?

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