First Light Guide #8: 56 And

56 Andromedae

A detailed guide to finding / observing the double star

First Light Guide 8 graphicFirst Light Guides #8 is a detailed written and video reference to finding and observing the double star 56 Andromedae in the constellation of Andromeda. This guide is ideal for beginners, but many advanced amateur astronomers may find it useful. It is designed to help you locate this double star with almost any telescope. There is a video to using a magnified finderscope, red dot finder, or setting circles along written tips on observing 56 Andromedae.

Visitors who are new to this site may wish to get started here, while more advanced observers can search the First Light Guides by constellation, or by right ascension

Find 56 Andromedae in the sky

56 Andromedae is a line-of-sight double star within our own Milky Way galaxy. The primary, 56 Andromedae, is yellow G-class star 316 light years away. The secondary is not gravitationally-connected to the primary; it is K-class star almost three times farther away, at 921 light years. Observers under very dark skies or with larger telescopes under moderate light pollution may see the stars of NGC 752 immediately to the north-east of these two stars. Being able to spot stars of 11-th magnitude and dimmer is a must for that cluster, and it is well worth seeking out should you have the proper equipment and conditions.

If you have a magnified finderscope on your telescope, start here to find 56 Andromedae:

If you have a red dot finder on your telescope, start here to find and observe 56 Andromedae:

If you have a telescope that has an equatorial mount with fairly precise setting circles, you may find this video useful when trying to find 56 Andromedae:

Video not available yet, but coming soon!

Observing tips:

This is a wonderful line-of-sight alignment. G-class star 56 Andromedae at 316 light years is forms a wide pair from our perspective with a K-class star that is some 3 times as distant. The G-class 56 And appears a lovely pale yellow, while the medium-sized G-class star is clearly a darker color in comparison. Most observers will likely see the unequal color and say it appears orange. 

At about 200 arc seconds of separation - over 3 arc minutes - these stars are easily separated in binoculars too. So magnified finder users will probably see the dual-nature at their finderscopes. Use LOW power, and for those with larger telescopes under slightly darker skies? The delicate and large open cluster NGC752 is on the way from Almaak to 56 And. Dozens of 9-th through 12-th magnitude stars burst into view here. 

Useful filter(s): None needed or required.

What should I see?

Below is an approximate view of 56 Andromedae as seen with a 70mm telescope at 38x magnification, and a 1.4 degree telescopic field of view.  

Demonstrates how view would look with objects on the meridian using a refractor telescope and a star diagonal.  Other telescopes or object sky positions may incur a differing view.  Various magnifications, eyepieces, telescope focal lengths and other variables may alter the view compared to this one.  This is a representation only intended to help the observer get some idea what they may see at the eyepiece.  Extreme local light pollution may block the view entirely.

Approximate view of 56 Andromedae as seen at 38x

Details of 56 And / HD11727

Type: Double Star (optical)

Distance: 316 / 921 light years

Spectral Type: G8III / K5III

Apparent magnitudes: 5.7 / 5.9

Right ascension: 01h 56m 9.6s

Declination: +37 15' 07"

Because telescopes and observers are all different, here are some alternate sketched/drawn views of 56 Andromedae, HD 11727 / NGC 752 (note that most sketchers draw NGC 752, not the double star):

Unknown sketcher, 102mm refractor - good representation of what small scopes show

Unknown sketcher, image shows 56 And very near the edge of the field

The constellation: Andromeda

General information about Andromeda, the Chained Princess, where 56 Andromedae is located. This will help you know where to find the constellation in the sky and be able to locate and identify its brightest stars.

Name of constellation: Andromeda

Abbreviation: And

Genetive form: Andromedae

Common names: Andromeda, The Chained Princess

Associated asterisms: One star forms the fourth point in the "Great Square of Pegasus"

Original 48 of Ptolemy: Yes

Area by size: 722.28 square degrees

Relative size: 19 out of 88 (Camelopardalis is next larger, Puppis is next smaller)

First Light Guides objects: Messier 31, Messier 32, 56 Andromedae, Gamma Andromedae

Brightest stars, in order of magnitude 

First lists the Bayer designation, then the "traditional" star name (often Arabic, but not always - see each star's notes for details).

  • α (Alpha) Andromedae (Alpheratz, Sirrah) magnitude 2.06, the 55th brightest star in the sky. It represents Andromeda's head in Western mythology, however, the star's traditional Arabic names – Alpheratz and Sirrah, from the phrase surrat al-faras – that means "navel of the steed". This is a reference to this star partially forming an asterism known as the "Great Square of Pegasus" with three more stars in Pegasusαβ, and γ Peg

  • β (Beta) Andromedae (Mirach) magnitude 2.06, is the 56th brightest star in the sky. Its name comes from the Arabic phrase al-Maraqq meaning "the loins" or "the loincloth".

  • γ (Gamma) Andromedae (Almach, Almaak) magnitude 2.15, is 62nd brightest star in the sky. Almach was named for the Arabic phrase ╩┐Anaq al-Ard, which means "the earth-kid", an obtuse reference to an animal that aids a lion in finding prey. Gamma Andromedae is one of the First Light Guides objects; it's object-locating guide is this page.