Linkblog

Dark Sky Finder

posted Nov 14, 2010, 9:37 AM by Christopher Leeney   [ updated Nov 14, 2010, 9:47 AM ]

This is a map of the world's approximate* sky brightness.  As a general measure of visual limiting magnitude it should help a lot with planning if we want to take any dark-sky trips.

Dark Sky Finder

*It's based on 10-year-old data of very low resolution, but in most cases the relative brightnesses are approximately the same.  Note there are other types of more localized light pollution that this cannot measure, and local conditions can be very different within one of these zones.

Galileoscope

posted Nov 13, 2010, 3:14 PM by Christopher Leeney   [ updated Nov 14, 2010, 9:49 AM ]

Galileoscope is a nonprofit program which tries to mass produce packs of affordable small telescopes of reasonably good quality which can be used for education.  A set of these might be something the club is interested in acquiring.

Excellent FITS training data

posted Oct 26, 2010, 6:46 PM by Christopher Leeney

This observatory has far fewer clouds, Ritchey-Cretien instead of Cassegrain telescope, and more wind than our setup, but other than that is nearly identical.  They've published great sets of FITS files of various objects so that people can get experience constructing images.  This is the level of quality we should aspire to achieve in our raw data - and it offers an excellent opportunity to try out various processing tools.

Messier Objects Poster

posted Oct 20, 2010, 10:22 PM by Christopher Leeney

In the late 1700's Charles Messier published a list of objects in the sky that were definitely not stars or comets.  Using a weak 4-inch refracting telescope, his goal was to note permanent, cloudy objects that were not visible from northern latitudes in order to assist people in finding comets, the mysterious cloudy entities that flew across the sky and changed position from one night to the next.  The 110 entities he found ended up being the nearest and brightest of five categories of objects that we today call 'Deep Sky Objects' - diffuse nebulae, planetary nebulae, open clusters, globular clusters, and galaxies - that were visible from the Northern Hemisphere.  His designations are still used for what became a very famous list of objects, and amateur astronomers sometimes hold "Messier Marathons" where they try to spot all of these relatively easy-to-see objects in one night.  This is what we're calling on when we refer to one of the brightest shapes in the sky as "M31 - Andromeda", and these tend to be the easiest visually interesting things to image outside our solar system.

Here is a nice poster and wallpaper of the Messier list in natural color, as well as a more detailed gallery, courtesy of Alistair Symon.

Solar Surface Behavior

posted Oct 20, 2010, 9:48 PM by Christopher Leeney   [ updated Oct 20, 2010, 10:18 PM ]

At the meeting today I was trying to find an amazing X-ray animation of a large solar filament erupting from a very active recent sunspot and breaking apart into burrowing helical currents & rapidly accelerating ejecta.  The hydrogen plasma in stars becomes turbulent in very different ways than what we are used to here on earth with convection - magnetic lines of force can be much more powerful than factors like gravity & pressure diffusion.  It's so alien to us that there are still frequent attempts to model and illustrate it in ways we can intuitively grasp, and while we have some general ideas that are accepted about these magnetically-driven plumes, predictive modeling is still an active area of research.

While it is certainly dangerous to configure telescopes with solar filters if you don't know what you're doing (I suspect what would happen to your eyeball or a CCD from an unshielded 32" reflector pointing at the sun is more like "explode" than "blind"), people can and do configure the same scopes they use at night for spotting duty to work on the sun in the daytime, with the right very low transmission protective filters before the primary and specific filters to measure the emission lines of particular elements.  They also buy purpose-built solar scopes.

Tri-Atlas Project

posted Oct 17, 2010, 3:29 PM by Christopher Leeney

The Tri-Atlas Project by José Ramón Torres and Casey Skelton is supposed to be an exemplary paper-style sky atlas, and it's freely available in printable PDF format.

Lucky Exposure Imaging Applied to Small Aperture Telescopes

posted Oct 3, 2010, 11:26 PM by Christopher Leeney

A nice overview of an interesting subject for us by Christian Weber.

S&T on Gliese 581g

posted Sep 30, 2010, 10:09 AM by Christopher Leeney

Last night's meeting, I mentioned that there were a lot of potential extreme problems with tidally locked planets.

Sixty Symbols

posted Sep 29, 2010, 7:11 PM by Christopher Leeney

From the "What if you put your hand in the LHC" video:

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