Andromeda VII

Dwarf Spheroidal Galaxy Andromeda VII (Cassiopeia Dwarf Spheroidal Galaxy), type dSph, in Cassiopeia

[And VII image, Keck]

RA:
23 : 27.8 (2000.0)
Dec:
+50 : 35 (2000.0)
Type:
dSph
RV:
Distance:
2600 kly
Apparent Dimension:
Diameter:
Brightness:
Abs. Mag:
Mass:
Andromeda VII was discovered in 1998 by a team of Russion and Ukrainian astronomers and originally named Cassiopeia Dwarf Spheroidal Galaxy (Cas dSph), together with Andromeda VI (the Pegasus Dwarf Spheroidal Galaxy). Its existence has been confirmed by Eva Grebel and Raja Guhathakurta with the Keck II 10-m telescope. And VII is another dwarf companion of the Andromeda Galaxy M31. The distance value for Andromeda VII, 2.6 million light-years, is adopted here from the average of Mike Irwin's and Van den Bergh's values, adjusted for the scale we use here.

Amateur sightings have been reported on the Internet Amateur Astronomers Catalog (IAAC) mailing list. Rich Jakiel observed it under good condition (visual limiting mag 6.0) on November 27, 1999 from Villa Rica, GA (USA) with a 20-inch f/4.5 reflector at 229x/260x. His description:

Suspected only, uncertain of 'true detection' due to a scattering of 11-14th mag stars on the western limb of the object. The view seemed more certain at the lower magnification, however the light scattering from the foreground stars detracted considerable at increased magnification.
Jay LeBlanc did another sighting of And VII on December 4, 1999 from Sonoita, AZ (USA) with a 32-inch f/4.5 reflector. He observed the galaxy with mag 281x and 183x, definitely perceived it, and describes it as follows:
(281x) A fairly large and very slightly brighter to the middle glow just E of, and involved with a N-S rectangle of faint stars with the brightest star 11.44 at the NE corner. 4.3' SW of the W member of an E-W 9.72-9.99 field double. The rectangle's W side points to a little knot of stars which looks non-stellar to the N inside a NE pointing isosceles triangle. This knot makes a small round spot!
(183x) Broadly brighter spot just E of the rectangle of faint stars.
References:


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Hartmut Frommert
Christine Kronberg
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Last Modification: March 9, 2000