Today's APOD | ... Editor's choices for the most educational Astronomy Pictures of the Day about individual stars: . APOD: 2000 June 11 - Sirius: The Brightest Star in the Night . Explanation: Sirius is the brightest star in the night sky. ... As Sirius is 8.7 light years distant, it is not the closest star system - the Alpha Centauri system holds this distinction. ... APOD: 2005 December 4 - Proxima Centauri: The Closest Star . ... APOD: 1999 October 6 - Polaris: The North Star . ... Index | ...

If you are an educator or astronomer interested in becoming a part of Project ASTRO?, or in using Project ASTRO materials, here are some ways you might get involved with us: . If you live near one of the Project ASTRO National Network Sites , contact the coordinator at your local site to get an application to be a Project ASTRO astronomer or educator. ... Learn More about Project ASTRO Educator-Astronomer Partnerships . ... Return to Project ASTRO: Getting Involved . ...

As the Universe expands, gravity pulls on the Universe, and slows the expansion down over time. As we look to great distances, we are looking back in time. If we can measure how fast the Universe is expanding in the past, and compare it to how fast it is expanding now, we can see the total gravitational effect of all matter in the Universe. Here we plot the distance between two galaxies as a function of time. ... Universes with lots of material . ...

... In this paper we present the results of detailed B, V, R, I, and H study of the isolated nearby blue compact dwarf (BCD) galaxy NGC6789. Judging from the literature the observed galaxy has not been resolved into stars up to now. ... The distance of the galaxy, estimated from the tip of the red giant branch (TRGB) is 2.1 Mpc which places NGC6789 close to the Local Group. ... Key words: nearby galaxies: dwarf galaxies (NGC 6789): distance moduli: star content . ... Distance. ...

... Home Education Classes AAA Winter Astronomy Class: Measuring Distances in Space тАУ Dec 2015 тАУ Feb 2016 . ... Classes . AAA Fall Astronomy Class: Astronomy Basics тАУ October-November 2015 . AAA Winter Astronomy Class: Measuring Distances in Space тАУ Dec 2015 тАУ Feb 2016 . AAA Spring Astronomy Class: The Physics of Astronomy тАУ February - March 2016 . ... This MonthтАЩs Sky тАУ April 2016 . ... Dec. ... Observing Resources for Amateur Astronomers - Part 1: Beginning Observers . ...

... The Round Earth . 8a. The Horizon . ... 9a. Earth orbits Sun? . ... What is the distance D to the horizon? ... Your line of sight to the horizon is a tangent to the Earth--a line which touches the sphere of the Earth at just one point, marked B in the drawing here. ... From the top of Mauna Kea on Hawaii, an extinct volcano about 4 km high (also the site of important astronomical observatories), the horizon should be about twice as distant, 226 km. ... One more: Distance to the horizon on Mars . ...

Hipparchus (and possibly Aristarchus before him) also derived the Moon's distance from the duration of a lunar eclipse . Because the Earth casts a much larger shadow than the Moon, such an eclipse usually darkens the entire Moon, for several hours. ... If the Sun is assumed to be very distant, and if the Moon crosses the middle of the shadow (if not, corrections must be made), the width of the shadow is expected to be about 2r , twice the Earth's radius r . ... Last updated 4 February 1999 Moon. ...

polimodel -- Produce model linear polarization and position angle images . ... Whether to apply random errors to output polarization and position angle values. seed = "" [integer] . ... This task produces a model linear polarization image and corresponding position angle image from an input image assumed to represent intensity (Stokes I parameter). ... A threshold for the input image can be defined such that polarization and position angle are not computed for input values less than this threshold. ...

... Ciel Espace, le magazine qui vous guide toujours plus loin . ... des actualitГїs . ... des interviews, des portraits . les plus belles images de l'Univers dГїcryptГїes pour vous . ... des pages consacrГїes Г la publication de vos photos Mais c'est aussi une vraie communautГї avec laquelle partager votre passion et nourrir votre curiositГї. Accueil Г? la une A quelle distance sont les Гїtoiles ? ... A quelle distance sont les Гїtoiles ? ... 23/05/2014 - Les cratГЕres de Mars sont-ils Г vendre ? ...

To main of Laboratory . The research work and design of optical and optical-electronic devices are carries out by laboratory staff: . ... Lens: . ... In the layout 1 prism systems perform functions of dispersive element, corrector of aberrations, optical reducer. ... Spectral range 200 - 400 nm; . ... Back Forward . ... The main corrector's function are compensation of field aberrations of the main spherical mirror of a telescope (diameter of 600 mm, f'=1200 mm) and increase aperture ratio. ...