Monthly Messier Star-Hop; November #1
By Art Russell

The air is finally clear as our southeastern humidity has fallen to acceptable levels.  What does this mean to us as astronomers?  One of the most important benefits of low humidity is decreased haze and its associated sky-glow, the bane of all good astronomers.  With the decrease in sky-glow we can now much more readily find low surface brightness objects which could be best seen only as a pale ghost of themselves only a month ago.  This month’s star hops will take us to two low surface brightness galaxies who’s visibility noticeably improves with the decrease of atmospheric moisture and sky-glow, M31, the “Great Andromeda Galaxy,” and M33, the “Pinwheel Galaxy.”  Along the way, we’ll take a few side trips to M31’s companion galaxies, M32 and M110, with our final destination being M74, a sometimes difficult to observe faint galaxy in the constellation Pisces.  

Star-Hop #1, M31, NGC224, the “Great Andromeda Galaxy,” M32, NGC221, and M110, NGC205
Star-Hop #2, M33, NGC598, the “Pinwheel Galaxy”
Star-Hop #3, M74, NGC628

This month’s star-hops will be near the Zenith (which is located directly overhead) 10 PM on the evening of 15 November and therefore easier to find.  Because of its convienent location in the sky, we’ll use the “Great Square of Pegasus” as our starting point for this month’s star-hops.   Take a quick look at our accompanying map for our star-hops.  You should see that the “Great Square of Pegasus” is aligned essentially north-south and east-west.  This one aspect will help us quickly locate this month’s star-hops.

Star-Hop #1, M31, NGC224, the “Great Andromeda Galaxy,” M32, NGC221, and M110, NGC205.  We start off this month with one of my favorite objects, M31.  Once the sky gets dark enough, this galaxy seems to go on and on.  Moreover, you don’t need a high-tech telescope and digital setting circles to find this object; it is visible to the naked eye under dark country skies and even at Villa Rica!  There are several ways to locate M31.  However for this month we’ll start at the “Great Square of Pegasus.”  Once you have located the “Great Square of Pegasus”  find the northeastern most corner star, Alpha (a) Andromedae, Alpheratz (actually in the constellation Andromeda although a part of the “Great Square of Pegasus”).  From there imagine a letter “V” such as the “V for Victory” made with your first two fingers on your hand.  Extend this imaginary “V” to the northeast of Alpha  Andromedae for about 7 degrees, the distance spanned by your four fingers held at arms length against the sky (incidentally, the length of your fingers in a “V” are about the right length here as well).  Here you will find the stars Delta (d) Andromedae and Pi (p) Andromedae.  Continuing in the same general direction to the northeast, we extend another imaginary line about the same distance as before, except this time to the stars Beta (b) Andromedae and Nu (n) Andromedae.   From the northern most of these two latter stars, Nu (n) Andromedae, it is only about 1 1/2 degrees, or little more than the width of one of your fingers, to M31.  In binoculars and small telescopes, M31’s galactic bulge will appear as an oblong haze with an increasing concentration of  stars in its central nucleus.  The edges of the galactic bulge or halo fade uniformly although there are hints of lane structure evident.  Moderate sized telescopes will reveal a very bright center with and intense concentration of stars.  In size, M31 will generally be one of the biggest objects you can see in your binoculars or telescope (where it often takes up many fields of view even at the lowest magnification).

M31 at 15X.

M32, one of M31’s several companion galaxies is located only about 20 arcminutes due south of M31’s nucleus and is generally not easily visible with small binoculars or small telescopes except at high power.  A medium sized telescope will reveal M32 as a compact, but diffuse galaxy.  To find it, scan south of M31’s nucleus where you’ll M32 as a bright concentration of light.

M110, another of M31’s companion galaxies is located about 1/2 degree northwest of M31’s nucleus and like M32, is generally not easily visible with small binoculars or small telescopes except at high power.  Similarly, in a medium sized telescope, M110 is relatively compact with a relatively bright central core and diffuse body.  Of the two companion galaxies mentioned, M110 is perhaps twice as large as M32.

Star-Hop #2, M33, NGC598, the “Pinwheel Galaxy.”  Head for a dark site to find this galaxy.  You’ll be glad you did!  M33 is another galaxy located near the “Great Square of Pegasus.”  Lets start from Beta Andromedae which you already found in the last star-hop.  From Beta Andromedae, M33 is about 7 degrees to the southeast.  There, under dark and transparent skies, you may even be able to see M33 with the naked eye (but you will need good eyes).  However, finding M33 can prove to be difficult.  If your skies are less than pristine, M33 becomes increasingly difficult to find as it is a relatively low surface brightness face on spiral galaxy.  That said, if you find it under good skies, you won’t forget it!  In binoculars M33 appears distinctly oblate in shape and looks much like a dim patch of soft light.  Its body is broadly concentrated with no stars resolved.  In medium sized telescopes under less than pristine skies M33 may appear as an unresolved low surface brightness concentration of light with little or no details.

Star-Hop #3, M74, NGC628.  M74 is an often overlooked galaxy also in the general area of the “Great Square of Pegasus.”  The biggest problem with finding M74 is the perceived lack of good “finder” stars in the area.  However, given the proximity of the “Great Square” and Eta Pisces in the constellation Pisces, this is a fallacious assumption!  Enough said; lets head back to the “Great Square” to get started.  In this case locate the two southernmost stars in “Great Square,” Alpha (a) Pegasi, Markab to the west, and  Gama (g) Pegasi, Algenib, to the east.  Extend an imaginary line from Alpha Pegasi through Gama Pegasi.  Continue this line to the east for a distance of about 18 degrees, or a bit more than that between Alpha  Pegasi and Gama  Pegasi, or just a bit less than that the distance spanned by your thumb and little finger held at arms length against the sky.  At this location you will find the star Eta (h) Pisces.  From Eta Pisces, M74 is a little more than 1 degree to the east-northeast, or the distance spanned by your little finger against the night sky at arms length.  In medium sized telescopes M74 should be visible at low power as a faint smudge of nebulosity distinct from the background sky.  At higher powers the galaxy stands out a bit better, but this galaxy will reveal little detail.