Mizar and Alcor, Double Star in Big Dipper

ArchRival · 10th April 2009

Not a good night for astrophotography. The moon was almost full, and images show low contrasts between stars and background sky. And the bloody mount suka suka anyhow drift in declination. In the end could only get 3 good images to stack, hence the noise.

Anyways, these are a famous pair of double stars in Ursa Major. They are not true binaries, given they are too far apart. Mizar itself has a true companion, but the 200mm f4L cannot resolve it. All 3 stars have been shown to be spectroscopic binaries.

Sidus Ludoviciana is an extra star in the background not related to the Mizar-Alcor system.

cy_j · 10th April 2009

I didn't know there was a binary star system in the Big Dipper. (but I have 'lost touch' with astronomy eons ago)...

ArchRival · 12th April 2009

A large percentage of stars are at least double, but nobody knows for sure how many. A good candidate for observing is Epsilon Lyrae. Lyra can be seen in rising in the north-eastern direction at about 2am. You can't miss it, the leading star is Vega.

weixing · 13th April 2009

Hi,
Yap... full Moon period are always not a good time to take Astrophotography especially wide field shot.

Anyway, not a bad one especially you only stack 3 images.

Hope to see more of your astro images and hope more clear sky ahead.

Have a nice day.

10th April 2009	#1
ArchRival Member Join Date: Sep 2006 Posts: 117	Mizar and Alcor, Double Star in Big Dipper Not a good night for astrophotography. The moon was almost full, and images show low contrasts between stars and background sky. And the bloody mount suka suka anyhow drift in declination. In the end could only get 3 good images to stack, hence the noise. Anyways, these are a famous pair of double stars in Ursa Major. They are not true binaries, given they are too far apart. Mizar itself has a true companion, but the 200mm f4L cannot resolve it. All 3 stars have been shown to be spectroscopic binaries. Sidus Ludoviciana is an extra star in the background not related to the Mizar-Alcor system. Last edited by ArchRival; 10th April 2009 at 08:24 PM.

10th April 2009	#2
cy_j Member Join Date: Sep 2004 Location: Newton Posts: 727	Re: Mizar and Alcor, Double Star in Big Dipper I didn't know there was a binary star system in the Big Dipper. (but I have 'lost touch' with astronomy eons ago)...

12th April 2009	#3
ArchRival Member Join Date: Sep 2006 Posts: 117	Re: Mizar and Alcor, Double Star in Big Dipper A large percentage of stars are at least double, but nobody knows for sure how many. A good candidate for observing is Epsilon Lyrae. Lyra can be seen in rising in the north-eastern direction at about 2am. You can't miss it, the leading star is Vega.

13th April 2009	#4
weixing Member Join Date: Feb 2005 Posts: 382	Re: Mizar and Alcor, Double Star in Big Dipper Hi, Yap... full Moon period are always not a good time to take Astrophotography especially wide field shot. Anyway, not a bad one especially you only stack 3 images. Hope to see more of your astro images and hope more clear sky ahead. Have a nice day.