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NGC3079

(Close-up view)

Information...

NGC3079 is a small faint spiral galaxy in Ursa Major, located about 50 million light years away. It is a Seyfert type galaxy with an active core powered by a massive black hole.

Also in the image are is the twin quasar QSO 0957+561 A/B. Although it looks just like a binary star, it is the first object to be identified as 'gravitationally lensed', which results in it appearing in double. There is a time delay of 417 days between each image and the quasar is approx. 8.7 billion light years away...

The 'faint fuzzy' to the right of NGC3079 is NGC3073, a galaxy about 72.7 Million light years away.

For more info. see the NGC3079 and Twin Quasar Wikipedia entries.

 

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Map

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Measuring Angles

Hold your arm at full length, then close one eye & use the hand shapes shown above to measure the angular distance between the stars.

(Ain't anatomy wonderful!)

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Apparent Magnitude

The apparent magnitude of a star is a measure of how bright it appears from Earth. The scale was introduced over 2,000 years ago by the Greek astronomer Hipparchus, who grouped stars into six categories. The brightest 20 or so were deemed to be 'first magnitude', slightly dimmer stars 'second magnitude', and so on until the barely visible stars were classed as 'sixth magnitude'.

Later it was recognised that our eyesight, once it has been given time to get used to darkness, has a logarithmic response. i.e. a Mag. 1 star is actually 2.512 times brighter than a Mag. 2 star, or 6.310 times brighter than a Mag. 3 star (2.512 x 2.512 = 6.310).

The six Magnitudes thus corresponds to a 2.5126 difference in brightness or 100x.

Apparent magnitude

Today the scale has now been extended, so that brighter objects can have an apparent magnitude of 0 or even negative. The brightest star Sirius, for example, has an apparent magnitude of -1.44 and the Sun is a whopping -26.74, due to it's close proximity to Earth.

 

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