Exploring Scutum
By Shawn Grant
This month we are going to learn how to star hop with just your eyepiece. You will want to use an eyepiece with a field of view of a degree or more. As mentioned in a previous article you will need to make an eyepiece overlay to match your eyepiece field with your charts. This is done by finding out what field of view your lowest magnification eyepiece yields and making a circle of that field to match the scale on your charts. I am going to share with you a star hop I did at the last star party exploring the constellation of Scutum. I will describe what I saw and how to find the objects and maybe at your next observing session you can practice using this region of the sky and the techniques I described.
Saturday August 22 the star party was at Clingmans Dome and what a sky. When we first got there the skies looked a little iffy. There was a layer of clouds overhead and more on the horizon. Luckily as it got darker the clouds dissipated and soon we had crystal clear skies. The view was spectacular. The Milky Way stretched from the southwest horizon near the base of Scorpius all the way through Cassiopeia in the northeast. There were so many stars that it was hard to make out some of the well known constellations. Stars of 7th magnitude were easily seen with the naked eye. The skies that night were truly remarkable.
To start our star hop we need to find the constellation of Scutum the shield. It is located between Aquila and Sagittarius. It lies in the heart of the Milky Way and looks like Cancer except a little smaller. Our start off point will actually be in Aquila. Point your telrad on the 3.5 magnitude star Lambda Aquila.
Before we move on here is some tips. First the charts. You will need either Uranometria or charts you printed from Guide or MegaStar. Sky Atlas 2000 isn’t detailed enough and won’t show many of the objects mentioned. The facts that Sky Atlas 2000 doesn’t show many of the objects in this star hop, don’t let that scare you. I assure you all objects will be visible in a six-inch or larger telescope. Look at how this region is tilted in the sky. Tilt your charts to match this. If you have a newtonian scope flip your charts over so they read upside down.
Move a degree north of Lambda Aquila to the dark nebula B135 (also B136). A dark nebula is
composed of gases and dust. The gases and dust are not illuminated it just simply blocks the light of the stars that are behind it. So what you see is an area that seems devoid of stars or fewer stars compared with the rest of the field. B135 is fairly large 50’ X 30’ in size. Look for an elongated void area. It is very obvious and easy to pick out.
A degree to the southwest you will find a smaller dark nebula B132. It is smaller 16’ X 8’. The field around B132 is very rich in stars, which makes B132 very easy to find. Point your telrad on the 4.2 magnitude star b Scutum.
44 minutes to the east you will come to a very prominent dark nebula B110. It is 9 minutes in size and elongated in shape. This area is very pretty in a wide-angle eyepiece with both B110 and B113 30 minutes to the north.
Move 30 minutes to the south and you will come to a nice open cluster NGC 6704. It is 9.2 magnitude and 5 minutes in size. There are about thirty stars in the cluster with most of the congestion to the west. The cluster is fairly loose but still is well detached from the rest of the star field.
A degree due south and you will come to perhaps one the best open star clusters in the sky. This cluster is M11 the wild duck cluster. It is 5.8 magnitude and 13 minutes in size. The cluster is bright very compressed and very rich. The cluster has a V shape that gives it the name wild duck cluster.
A degree northwest of M11 you will see a triangle of three 7th and 6th magnitudes stars. Look on the northern side of the triangle and you will see a faint scattering of stars. That is the open cluster Basel 1. The cluster is 8.9 magnitude and 9 minutes in size. It is well detached and fairly rich. It is one of the better clusters of the Basel catalogue.
2 degrees to the west of M11 is the open cluster NGC 6683. This cluster is 11 minutes in size and a brightness of 9 magnitude. This cluster is very hard to pick out from the background. The rest of the area is a huge mass of stars very rich because of the cluster doesn’t make itself known. Point your telrad to the 3.8 magnitude star a Scutum.
Just 22 minutes to the east of that star is the cluster NGC 6664. NGC 6664 is magnitude 7.8 and
16 minutes in size. The cluster is fairly large and easy to pick out from the background. It isn’t that rich and widely scattered. M26 our last object is 2.4 degrees to the east of NGC 6664. It is 8th magnitude and 14 minutes in size. It is bright and fairly rich. Most of the concentration is in the east. M26 is often overlooked due to M11 just to the north. Take a look at M26 it is a very nice cluster.
You may have noticed I haven’t been very detailed with explaining how exactly how you star hop with your eyepiece. Basically this is learned only with experience. This star hop is a good start see if you can chart some others. It is one of the best ways to explore the sky.
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