Einstein Cross

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This article is about a specific multiply-imaged quasar named "The Einstein Cross" . For the general concept of Einstein crosses, see gravitational lens.
QSO 2237+0305
Einstein cross.jpg
Observation data (Epoch J2000)
Constellation Pegasus
Right ascension 22h 40m 30.3s
Declination +3° 21′ 31″
Redshift 1.695
Distance 8,000,000,000 ly (2,500,000,000 pc)
Type LeQ
Apparent dimensions (V) less than 2"
Apparent magnitude (V) 16.78
Other designations
LEDA 69457, Z 378-15
See also: Quasar, List of quasars

The Einstein Cross or Q2237+030 or QSO 2237+0305 is a gravitationally lensed quasar that sits directly behind ZW 2237+030, Huchra's Lens. Four images of the same distant quasar appear around a foreground galaxy due to strong gravitational lensing.[1]

According to current interpretations of redshift, the quasar is located about 8 billion light years from Earth, while the lensing galaxy is located at a distance of 400 million light years.[2] The apparent dimension of this galaxy is 0.87x0.34 arcminutes, while the apparent dimension of the cross in its center accounts for only 1.6x1.6 arcseconds.

The Einstein Cross can be found in Pegasus at 22h40m30.3s, +3° 21′ 31″.

Amateur astronomers are able to see some of the cross using telescopes but it requires extremely dark skies and telescope mirrors with diameters of 18 inches or greater.[3]

The individual images are labelled A through D (i.e. QSO 2237+0305 A), the lensing galaxy is sometimes referred to as QSO 2237+0305 G.

Hubble space telescope captures Einstein Cross.

See also[edit]


  1. ^ Overbye, Dennis (March 5, 2015). "Astronomers Observe Supernova and Find They’re Watching Reruns". New York Times. Retrieved March 5, 2015. 
  2. ^ NASA and ESA (September 13, 1990). "The Gravitational Lens G2237 + 0305". HubbleSite. Retrieved July 25, 2006. 
  3. ^ Crinklaw, Greg. "Focus on Einstein's Cross". Retrieved 2013-06-29. 

External links[edit]

Coordinates: Sky map 22h 40m 31.0s, +03° 21′ 30.3″