One of my favorite activities is to introduce new telescope users to the wide variety of objects that are visible in the night sky. To be successful, this first list of targets must be interesting and relatively easy to find. This month, I will go through my list of six suggested objects for a small telescope that has no built-in star-finding ability, such as an 8-inch Dobsonian.
If you are a new user, this relatively short list might well fill up your entire evening as you learn to use your telescope and charts, but I hope it will leave you wanting more.
My list includes a planet, a double star, a star cluster, a planetary nebula, an emission nebula and a galaxy. These are not necessarily my favorites of these object types, but they are all good examples. And all are relatively easy to find as long as you can relate a star chart or guidebook to the actual stars.
Find-ability is an important criterion for new telescope users. You should always begin any object search with an eyepiece with the lowest possible magnification. When your object is well centered, you can change eyepieces to a higher magnification.
Because planets are often the brightest things in the sky, you can begin your observing session soon after sunset, and before it gets completely dark. If Saturn is above the horizon, I always choose it as the planet to look at. Saturn is very bright, so it is easy to find. The rings show up well even under modest magnification. Saturn is a good target to practice changing eyepieces to get to the highest possible magnification. If it ever drifts out of the field of view in high power, the easiest way to re-find it is to go back to a lower power eyepiece and re-center.
For double stars, I like to pick ones with contrasting colors. Alberio, at the head of Cygnus the Swan, fits the bill, as it is relatively bright and shows the distinct orange and blue colors representing the different surface temperatures of the two stars.
My next target is the globular star cluster M13. This is only visible to the naked eye from a very dark site but is a good object to practice something called star hopping. By looking at the surrounding stars, in this case the keystone asterism in Hercules, M13 will show that you can point your telescope to an apparently blank spot between two stars and find something interesting.
The planetary nebula in my list is M57, the Ring Nebula. It is also right on a line between two closely spaced naked-eye stars, in the constellation Lyra. M57 presents a new challenge. It is so small that in your lowest power eyepiece, it is easy to mistake for just another star.
The Lagoon Nebula, also known as M8, is the second-brightest emission nebula in the sky. This nebula gives you a chance to try out observing using averted vision. This is where you can see more of what you are looking for by looking off to the side of your field of view rather than directly at the nebula.
For the galaxy in my list, none compare to M31 in Andromeda. Although the spiral arms you see in photographs are too broad to fit in the field of view, the core shows up nicely. As a bonus, the companion galaxies M32 and M110 are usually in the same low-power field of view as the core of M31.
Although it isn’t on my list, the moon makes a nice final target. It has to be last because it is so bright that it will ruin your night vision for the dimmer objects.