TELESCOPIC HIGHLIGHTS


March is the first month that marks what I call, "The Galaxy Season." There're many to see in three major clusters named after the constellations in which they reside. They are the Leo, Coma, and Virgo clusters. We'll start by identifying the two largest looking galaxies in the constellation Leo The Lion, NGC 2903 and 3628. Both these galaxies can be seen in a dark sky location using a small telescope with a high power eyepiece and averted vision to see the general shapes of what look like ghostly mist. However, they are far enough away that it'll take a time exposure using a DSLR or astronomical camera to bring out any detail.

This is the position of NGC 2903 about an hour after sunset on March 8. The Moon's glare won't interfere with dim deep space objects like this during the first week of March. If you don't get a chance to view NGC 2903 by March 8, you'll have to wait until March 22 through the end of the month to see it on a moonless night. You'll also need to view this galaxy later because daylight savings time will be in effect.
NGC 2903 is a barred spiral equipped with two typical dominating spiral arms that emanate from each end of the bar structure in the galaxy's mid section. It's also designated as a "field galaxy" which means it's in a field all by itself not gravitationally associated with any particular galaxy group. It is, however, part of the Virgo Super Cluster of Galaxies which we'll get a better look at in April and May. NGC 2903 lies 20 to 30 million light years away depending on which astronomy website you go to. It's generally accepted that NGC 2903 is about 80% the size of our Milky Way which is also a barred spiral although the Milky Way's central bar is not as extensive. Each of the red colored blobs in the spiral arms are star forming emission nebulae called H2 Regions because of the propensity of ionized hydrogen. For comparison, the Great Orion Nebula and Rosette Nebula are H2 Regions in the Milky Way. Blue areas are reflected light (reflection nebulae) from hot young blue star clusters. Other individual stars surrounding NGC 2903 are foreground stars in the Milky Way because there is no way we can see individual stars in this distant galaxy.
Sarah's Galaxy (NGC 3628) is the largest of the two galaxies showcased here. It's apparent size is 15 x 3.6 arc minutes compared to NGC 2903 at 12.6 x 6 arc minutes. NGC 3628 is also known as the Hamburger Galaxy because of its peculiar shape. Unlike NGC 2903, Sarah's Galaxy is a gravitaionally bound member of the Leo Group of galaxies. In fact, it's part of the famous Leo Triplet along with M65 and M66. These three galaxies interact in a way that their gravitational tidal forces combine to disrupt NGC's smooth spiral structure into a kind of frayed shape at its edges. I researched why NGC 3628 is called Sarah's Galaxy, but have found no reliable results. The closest guess I've seen is that it was named after a 19th century poet, but there's no proof of this claim.
NGC 3628 presents itself to us edge-on (probably a spiral galaxy) with a prominent dark dust lane along its perimeter. There is a 300,000 light year long tidal tail coming from the upper left edge of this galaxy (not seen in this image). Other larger field images show the tidal tail along with the two other companion galaxies M65 and M66.