Cepheid Variable Stars: Cosmic Distance Rulers
Discover how Cepheid variable stars work, their period–luminosity law, and how astronomers use them to measure extragalactic distances and refine H0.

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Information on Galaxies, Stars, Constellations, Planets, Moons, Comets and Asteroids
Listen to Bernard Miller describe his journey into AstroPhotography and detail how he captured this stunning image of the Sculptor Galaxy.
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Drew Evans talks about his passion for astrophotography, the equipment used and tips for post processing image data.
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Hear D.j Van Bourgondien as he talks about using his Celestron EdgeHD 8″ telescope to capture this image of the Fireworks Galaxy
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Discover how Cepheid variable stars work, their period–luminosity law, and how astronomers use them to measure extragalactic distances and refine H0.

Dobsonian telescopes are the ultimate tools for observing the vast scintillating unknown. They provide you with far greater apertures than your typical telescope, giving you brighter, clearer views of deep space objects, sating your innate astral curiosities in ways that you never thought possible. So, if that all sounds good to you, fantastic, you’re in
Learn how numerical aperture sets true resolution, how magnification and sampling interact, and how illumination and contrast affect what you can really see.