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Andromeda - Triangulum - Lacerta Andromeda - Triangulum - Lacerta Image Map
Exposure Data
  • Image Field of View: 63.5° x 45°
  • Camera Field of View: 63.5° x 45°
  • Lens: Canon 18 mm f/3.5-5.6 EF-S IS
  • Focal Length: 18 mm
  • Focal Ratio: f/5.6
  • Camera: Modified Canon T3i (600D)
  • ISO: 800
  • Exposure: 6 x 300 seconds (30 minutes total)
  • Filter: None
  • SQM: 20.81


Andromeda is a northern constellation that is named after the princess Andromeda in Greek mythology.

Hold your mouse cursor over the image to see constellation figures, boundaries, and star identifications.

Andromeda was the daughter of Cepheus, the King, and Cassiopeia, the Queen. Sometimes called the "Chained Maiden", Andromeda was chained to a rock and left to the sea monster Cetus to appease the gods. She was rescued by Perseus. All of the main characters in this tale have been immortalized by having constellations named after them.

Alpha Andromedae is Alpheratz, a second-magnitude star that also marks the northeast corner of the great square of Pegasus asterism. Alpheratz is a spectral-type B9II hot blue variable star that varies in magnitude from 2.02 to 2.06. It is located 97 light-years away. Alpheratz was once considered part of the constellation of Pegasus and was given the designation Delta Pegasi. This designation, however, is no longer used.

Beta Andromedae is Mirach, a spectral-class M red-giant star that shines at magnitude 2.07 and is located 199 light-years distant.

Gamma Andromedae is Almach. It shines at magnitude 2.10. It is located at the end of one of the main arms of the constellation. In a small telescope, Almach appears as a beautiful gold-and-blue double star separated by almost 10 arcseconds.

VX Andromedae is a very red carbon star. Its magnitude varies from 7.8 - 9.3, and has a B-V index of +5.6. Astronomers calculate the "redness" of a star by measuring it through B (blue) and V (visual) filters and then subtracting the V value from the B value. The higher the plus number, the redder the star is. Stars range in color from -0.5 for a very blue star to over +5 for very red stars. Our Sun has a B-V index of 0.65.

Andromeda contains several different deep-sky objects including the spectacular galaxy Messier 31 (the Great Galaxy in Andromeda), its satellite galaxies Messier 32 and Messier 110, edge-on galaxy NGC 891, galaxy NGC 404 (Mirach's ghost), open cluster NGC 752, planetary nebula NGC 7662 (the Blue Snowball), and the faint reflection nebula VdB 158 (the Blue Flame).

Andromeda was cataloged by the Greek astronomer Ptolemy in the second century C.E. (Common Era). It is the 19th largest of today's 88 modern constellations, covering 722 square degrees of sky.


Triangulum is a northern constellation whose name means the "Triangle" in Latin. Triangulum is a small constellation seen in the shape of a long, narrow triangle.

Alpha Trianguli is known as Caput Trianguli or Ras al Muthallah which means the "Head of the Triangle." It is the second brightest star in the constellation, shining at an apparent magnitude of 3.42. It is a spectral-class F spectroscopic binary whose primary is a giant or sub-giant star. It is located 64 light-years away.

Beta Trianguli is the brightest star in Triangulum. It shines with an apparent visual magnitude of 3.0 and is located 127 light-years from Earth. It is a spectral class A white giant star which is also thought to be a spectroscopic binary.

Gamma Trianguli, the third brightest star in the triangle that forms the shape of the constellation, shines at magnitude 4.01 and is located 112 light-years away. It is a spectral-class A main-sequence star.

Triangulum contains one Messier object, spiral galaxy M33, the Triangulum galaxy. It also contains the barred spiral galaxy NGC 925.

Triangulum was cataloged by the Greek astronomer Ptolemy in the second century C.E. (Common Era). It is the 78th largest of today's 88 modern constellations, covering 132 square degrees of sky.


Lacerta, the Lizard, is a small, faint northern constellation. It is located between Pegasus and Cepheus.

Alpha Lacertae shines at magnitude 3.76. It is a spectral-type A star that is located 102 light-years away. It is also an optical double star with an 11.8 magnitude companion that is located 36 arcseconds away. In Chinese, Alpha Lacertae is known as Téng Shé yi.

Beta Lacertae shines at magnitude 4.42. It is a spectral class G yellow-giant star that is located 170 light-years away.

Lacerta does not contain any Messier objects.

Lacerta was created as a constellation by the Polish astronomer Johannes Hevelius in 1687. It is the 68th largest of today's 88 modern constellations, covering 201 square degrees of sky.

North is to the bottom left in the above image.

Andromeda - Triangulum - Lacerta
  • Object Type: Constellation
  • Size:
    • And: 40° x 30°
    • Tri: 16.5° x 12°
    • Lac: 21° x 12°
  • Image Field Centered At:
    • RA: 01h 08m 41s
    • Dec: +35° 36' 53"

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