I am pursuing the first Herschel 400 catalogue of objects and most of them are galaxies. Though I am not one hundred percent sure about this, I believe numerically, there are more galaxies within range of my telescope than all the other objects combined. This being said, I would be hard pressed to describe most of them as spectacular like the Orion Nebula, the Great Cluster in Hercules, or the other classic objects everyone is so familiar with. There are of course, a few exceptions like the Andromeda galaxy or the Sombrero. For the most part, galaxies are faint fuzzy objects that sometimes have a shape but often are little more than the hint of something not quite as black as the background sky, even in my 16” scope.

One of the things you learn early in the use of your telescope is its' magnitude (or “mag”) limit. Say the mag limit of your scope is 14. What does this mean? Well… on a good dark night, your telescope has the capability of seeing a single pinpoint of light as dim as a magnitude 14. Would this apply to a galaxy? If the magnitude limit of your scope is 14 and you try to detect a magnitude 14 galaxy, you re probably not going to see anything! Why? The reason is fairly simple. A magnitude 14 star is a concentrated spot of light and is therefore visually brighter than a galaxy of the same magnitude whose light is spread out over a wider area. In other words, the galaxy appears much dimmer than its actual magnitude because the light is distributed over a larger area. It is like spraying off your sidewalk with a garden hose and an adjustable nozzle attached. The wide spray is okay for large sweeps but for the heavier material like gravel and dirt clods, you need to narrow the stream to concentrate enough pressure in one spot to move that stuff. In the sky, the photons from the star are concentrated and hit your eye harder as a pinpoint than the diffuse light of a galaxy that is spread out and much weaker. So what is the point of all this? To start an observing program for galaxies, you first need to know the magnitude limit of your telescope and knock it back by a factor of two. In other words, if your scope has a magnitude limit of 14, set up your program initially for galaxies that are no dimmer than 12. Ignoring this advice may lead to lots of eye strain headaches and little to show for it!

One way to handle your magnitude limit is to put the brighter objects at the top of your list and the dimmer ones at the bottom for when you have the time and want a challenge. Now before we move on, there is a point I need to emphasize. This mag rule is a rule of thumb, not an absolute! I have been surprised with some of the galaxies I've been able to spot when the conditions were just right. As far as I know, all of the Hershels (there are actually 800 total broken down into two separate lists) are within the range of my 16” scope. While searching for them I've spotted a few non-Herschel galaxies that pushed the limits of my scope. So it is possible to see galaxies at your mag limit, but not something to pursue as a primary part of your observing program. On the other hand, there are some experienced people that have made it their crusade to observe objects at the extreme mag limit of their scope and have met with surprising results. The best bet is to start easy and work your way up as you gain expertise.

Galaxies do not do well with filters. I've tried all the popular light pollution filters, plus the O-3, and the H-Beta and the results were the same, bad. The reason is that galaxies are faint already and emit a much wider spectrum of light than the filter allows and any light you cut out with a filter only hurts the image. The only success I've had with a filter on a galaxy was one time I tried the O-3 on the Triangulum galaxy, M-33 and saw a few clumps of nebulosity in the spiral arms. Most galaxies do not provide you with a face-on angle that is large enough to show that much detail.

Some galaxies appear so small that you want to crank up the power to see them better. Unfortunately, the higher the power, the dimmer the object becomes. When you are trying to see a faint fuzzy that is barley visible with averted vision, power is usually a bad idea. I use 82X for just about everything except planets and I've lost count of how many galaxies I've identified (several hundred according to my computer database). On some of the brighter ones, you can go up to 140X or so, but much higher than that and you will lose the delicate details unless it is an exceptional night and the object is exceptionally bright.

For smaller scopes, the Messier galaxies are the best bet. They are usually much brighter than the NGC galaxies and relatively easy to find in the sky. There is one exception and that is the Sculptor galaxy. Messier missed it in his catalogue but even in a small scope, it is quite impressive. I believe you can even see it with a 60mm refractor.

A few favorites of mine are the Sculptor galaxy, the Sombrero, M-81 and M-82. There is, of course, the Andromeda galaxy group M-31, M-32, NGC-205 (or M-110) but it has lost some of its thrill for me, kind of like looking at the moon too many times. My real thrill comes from showing it to other people and seeing their reaction. Another favorite of mine is Stephan's Quintet. This one is hard to see on a mediocre night but if it is dark enough, you can see all five galaxies in the same field but you need at least a 14” or larger scope. A nice little surprise for me was to see the NGC galaxy next to the great cluster in Hercules (M-13). I never noticed it with my 8” reflector because I was not using a very detailed chart (before I got my Tirion Sky Atlas). Once I obtained the Tirion and discovered it was there, on a good night I could just see it with that scope. It is easy to see with the 16”. This is an example of overlooking something because, though it is visible in your scope, it is too faint to notice unless you are specifically looking for it.

For the really faint galaxies, the trick is patience and averted vision. I star hop to find objects because GOTO's are not legal if you are going for observing certificates. I know where the galaxy is supposed to be from the star chart so I use the finder to star hop to the target area then sweep at the eyepiece from there. I will cover the area with a fairly fast sweep and if the galaxy is bright enough I can spot it easily. If not, I slow the scan rate. Many times, there are no reference stars or there may be some visible in the telescope but they are too dim to show up on the star chart.

On the fainter galaxies, your surroundings must be absolutely dark! No stray light can enter your eye. You may have to shield your eyes or put a hood over your head to ensure you have the best odds of spotting something. When the object is at the absolute mag limit, you may see nothing more than a slightly grayer (or lighter) area than the black background. By jiggling the scope, you may see that the lighter area jiggles with the stars. That is your clue that you are on target. With averted vision, you may start to see a slight shape, or you may see only a light area that you cannot assign a shape to.

So many factors affect spotting the fainter galaxies. Light pollution is a biggie. Do not even bother looking from in town, and if you are out of town, don't bother looking toward town if the sky glow blots out the faintest stars on your star map! Another factor that greatly affects your success is transparency. This is a tough one because you cannot always tell the transparency level by how “good” or how “dark” the sky looks. Looking at a planet is not always a good indication either. If a planet swims around and goes in and out of focus, you have upper turbulence, but not necessarily hazy skies. Another factor that does not help is the inconsistent nature of the sky. Transparency may be uneven and where it looks dark, it may be good seeing in patches that you cannot differentiate because of the dark background. So if you are not having luck seeing an object that is supposed to be within your magnitude limit, transparency may be the reason. Go on, try for something else, and save it for later in the night.

I have had more fun looking for faint and obscure galaxies than any other object. It gives me a sense of accomplishment that I am able to add another galaxy to my list. It also tests the limits of the telescope and the sky that particular night. There is a sense of adventure finding those elusive objects that do not make all the books and magazines, and they can be just as interesting.

Once, scientists aimed the Hubble space telescope at a blank part of the sky and just opened the shutter on the camera. An hour or so later, they discovered that the “blank” area of the sky was full of thousands of galaxies. Since then, even amateurs with a large backyard telescope and a good CCD camera can photograph that same area and see many of those galaxies. Just think, thousands of distant galaxies that show how tiny our little corner of the universe really is!

Photos provided by NASA