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DIY Bluetooth Remote Focus Control

Nov 21 2017 02:36 PM | skaiser in Articles

I came up with the idea of using an old Lego NXT Mindstorm control module and NXT motor I had laying around to drive my focus knob. The Mindstorm can be controlled via Bluetooth which is ideal for my control interface. This type setup could be adapted to most scopes if a convenient mounting location is available.

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Cosmic Challenge - NGC 404

Nov 17 2017 08:36 PM | PhilH in Phil Harrington's Cosmic Challenge

Did you know that I discovered a comet in the fall of 1973? I was out with my venerable 8-inch Criterion RV-8 Dynascope Newtonian reflector, just hopping around the autumn sky, when I noticed stars weren't focusing sharply. Thinking the telescope's collimation was off, I aimed at a nearby bright star to check whether the silhouette of the secondary mirror was centered correctly in the star's out-of-focus image. After I tweaked things a bit, all appeared well, so I focused on that star to check things before moving on. Lo and behold, I saw a dim blur of light right next to the star! Checking things further, it wasn't an internal reflection or an optical aberration.

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November 2017 Skies

Nov 17 2017 01:14 PM | cookman in This Month

Highlights: Comet Journal, Martian Landers, Meteor Showers, Planet Plotting, November Moon Focus Constellations: Auriga, Perseus, Cassiopeia, Andromeda, Pegasus, Cygnus, Lyra, Cepheus, Draco, Ursa Minor, Ursa Major, Lynx, Camelopardalis

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Reading optical measurement data

Oct 21 2017 12:47 PM | Benach in Articles

These days, interferometers become cheaper and therefore more common every day. This is an asset for amateur astronomy because this allows far better optics than in the days of only Foucault testing. In this short article, based on actual measurements of a secondary mirror, I will very briefly explain how to interpret this data.

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October 2017 Skies

Oct 07 2017 05:19 AM | cookman in This Month

Highlights: Comet Journal, Martian Landers, Meteor Showers, Planet Plotting, October Moon Focus Constellations: Auriga, Perseus, Cassiopeia, Andromeda, Pegasus, Cygnus, Lyra, Aquila, Hercules, Draco, Cepheus, Ursa Minor, Ursa Major, Camelopardalis

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Cosmic Challenge: Stephan's Quintet

Oct 01 2017 10:56 AM | PhilH in Phil Harrington's Cosmic Challenge

The canvas on which our picture of the universe is painted relies on the unwavering acceptance of Hubble's Law. Hubble's Law states that a relationship exists between the distance to a galaxy and the speed at which it is receding from us. The farther away a galaxy is, the greater the speed of its recession and farther its spectral lines are shifted toward the red end of the spectrum. For Hubble's Law and the Red Shift Principal to be valid, it must work for not just a few galaxies, but for all. And indeed, it does -- well almost.

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Six Months Observing Upside Down

Sep 02 2017 12:01 PM | bunyon in Articles

Traveling to the southern hemisphere is a topic that pops up frequently on Cloudynights and other amateur astronomy discussion groups where northern observers and imagers congregate. I’ve written this piece to try to share some of what I learned about doing amateur astronomy in Chile and Argentina. Obviously, even in six months it is impossible to do everything or go everywhere so this isn’t a comprehensive guide. Still, I hope it’s helpful and that it inspires a few people who have been wavering in their decision to head south.

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September 2017 Skies

Sep 02 2017 10:29 AM | cookman in This Month

Highlights: Comet Journal, Martian Landers, Meteor Showers, Autumnal Equinox, Planet Plotting, September Moon Focus Constellations: Perseus, Cassiopeia, Andromeda, Pegasus, Cygnus, Lyra, Aquila, Ophiuchus, Hercules, Draco, Cepheus, Ursa Minor, Ursa Major, Camelopardalis

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Cosmic Challenge 61 Cygni: Piazzi's Flying Star

Sep 01 2017 09:48 AM | PhilH in Phil Harrington's Cosmic Challenge

The star 61 Cygni is not bright, nor is it visually distinctive. To the eye alone, it looks just like any other 5th-magnitude point of light deep in the Milky Way flowing through the Swan. But looks can be deceiving! This unremarkable looking star is indeed quite remarkable for its unusually high rate of proper motion. By watching and plotting it against the backdrop of stars over the course of relatively few years, its position shifts at an extraordinarily fast pace. At present, 61 Cyg has a proper motion of more than 5 arc-seconds per year.

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Adapting Eyepieces for Binoviewing

Aug 29 2017 12:45 PM | The Ardent in Articles

Successful binoviewing entails one major requirement: both eyes must receive light from the objective. Now this sounds kinda obvious, right? Well it's not that easy. Most astronomical binoculars and binoviewers are hinged. This allows the two eyepieces to be spaced so that light enters both eyes. Some of us have a narrow IPD and facial structure that prevents optimal eye placement. In my case, the nose. It won't fit between some binocular eyepieces. It won't fit when binoviewing with complex, wide body eyepieces.

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