Category Archives: Double Stars

61 Cygni – Binary Star System

61 Cygni is a famous binary star system located in the constellation Cygnus. The two stars, both dwarf stars that show a neat orange tint, and both are smaller and more faint than our Sun. The two stars take nearly 700 years to complete a single orbit around each other. They are also famous for exhibiting a large proper motion, motion across the sky as seen from Earth, of over 5 arc-seconds per year, it has been dubbed by some as “The Flying Star”. The large proper motion is at least partly addressed by the stars close proximity to the Earth, only about 11 light-years away.

Tech Specs: Meade 12” LX90, Celestron CGEM-DX mount, Canon 6D stock camera, ISO 800, 45 second exposure using Backyard EOS, no darks or bias frames, guided using a Canon 400mm lens with an attached ZWO ASI290MC camera. Image Date: September 9, 2017. Location: The Dark Side Observatory in Weatherly, PA.

Additional information:

EarthSky (http://earthsky.org/brightest-stars/61-cygni-suns-near-neighbor)

Wikipedia (https://en.wikipedia.org/wiki/61_Cygni)

Sky and Telescope (http://www.skyandtelescope.com/observing/on-the-move-with-barnards-star-and-61-cygni06032105/)

…Tom

Delta Cephei – Cepheid Variable Star and Double Star

Delta Cephei is the prototype Cepheid variable, a class of giant stars that change brightness with periods proportional to their luminosity. You can read more about the variable nature of this star at EarthSky (http://earthsky.org/brightest-stars/delta-cephei-the-kings-famous-variable-star). This image shows the visual binary system. Delta Cephei is the brighter, yellow-toned star, and the companion has a slight bluish color. The blue companion is about 40 arc seconds away and is magnitude 7.5.
 
Tech Specs: Meade 12” LX90, Celestron CGEM-DX mount, Canon 6D stock camera, ISO 3200, 10 second single exposure using Backyard EOS, no darks or bias frames. Image Date: September 4, 2017. Location: The Dark Side Observatory in Weatherly, PA.
 
Additional Information:
…Tom

Zeta Lyrae – Double Star

I found myself wandering around with the telescope in a double star mood, it has been a long time since I viewed many of these and the first time imaging them. This is the binary system Zeta Lyrae, also referred to as Zeta 1 Lyrae and Zeta 2 Lyrae. The distance to this system is roughly 150 light years and their magnitudes are 4.3 and 5.7 respectively.

Tech Specs: Meade 12” LX90, Celestron CGEM-DX mount, Canon 6D stock camera, ISO 3200, 10 second single exposure using Backyard EOS, no darks or bias frames. Image Date: September 4, 2017. Location: The Dark Side Observatory in Weatherly, PA.

Additional information:

Wikipedia (https://en.wikipedia.org/wiki/Zeta1_Lyrae)

…Tom

Polaris – the Double Star

I’ll be honest, I really never viewed Polaris under any magnification before. I’ve always used it as a guidepost to align a telescope or other piece of astronomical equipment. While recently setting up my pier and Meade telescope for the first trial runs, I focused the scope on Polaris to begin alignment, and snapped a few quick pictures. That is when I noticed a little companion star right next to it! Low and behold, Polaris is a multiple star system with an 8.7 magnitude companion (see image in the two o’clock position). Polaris actually has another, closer star, designated Polaris Ab that amateur scopes can’t resolve. You can see a Hubble view of this star at:

https://www.spacetelescope.org/images/opo0602d/

Tech Specs: Meade 12” LX90, Celestron CGEM-DX mount, Canon 6D stock camera, ISO 3200, 10 second single exposure using Backyard EOS, no darks or bias frames. Image Date: August 25, 2017. Location: The Dark Side Observatory in Weatherly, PA.

Additional information:

…Tom

Epsilon Lyrae – The Double Double Star of Lyra

Epsilon Lyrae is the famous “double-double” star in the constellation Lyra (see below for the location). It lies very close to the star VEGA. The two brightest stars in the binary system can be seen with the naked eye under good conditions and with good eyesight, both stars lie around 162 light years from Earth and they orbit each other. At the time of this posting, Lyra is high in the Western sky after sunset.

Lyra - wide-field image photographed in 2015.

Lyra – wide-field image photographed in 2015.

When viewed at higher magnifications, both stars of the binary can be further split into binaries; that is, the system contains two sets of binary stars orbiting each other. Being able to view the components of each is a common benchmark for the resolving power of telescopes.

Below is an image of the primary double stars using a Celestron 6″ telescope and Canon 6D camera. Total exposure time was only 1.5 minutes.

Note the striking orange star HIP 91820 in the image, this is a spectral type K5 star. From WIKIPEDIA: These stars are of particular interest in the search for extraterrestrial life because they are stable on the main sequence for a very long time (15 to 30 billion years, compared to 10 billion for the Sun). This may create an opportunity for life to evolve on terrestrial planets orbiting such stars. K-type stars also emit less ultraviolet radiation (which can damage DNA and thus hamper the emergence of life) than G-type stars like the Sun.

I learn something new with every image I take….

Epsilon Lyrae photographed in July 2015.

Epsilon Lyrae photographed in July 2015.

Clear skies!

…Tom

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