NGC 4038/39. Image credit: Astro Physics. Click to enlarge.
Monday, May 30 – Legend tells us the constellation of Crater is the cup of the gods – cup befitting the god of the skies, Apollo. Who holds this cup, dressed in black? It’s the Raven, Corvus. The tale is a sad one – a story of a creature sent to fetch water for his master, only to tarry too long waiting on a fig to ripen. When he realized his mistake, the sorry Raven returned to Apollo with his cup and brought along the serpent Hydra in his claws as well. Angry, Apollo tossed them into the sky for all eternity and it is in the south they stay until this day.
This week it will be our pleasure to study the Cup and the Raven. The galaxies I have chosen are done particularly for those of us who still star hop. I will start with a “marker” star that should be easily visible unaided on a night capable of supporting this kind of study. The field stars are quite recognizable in the finder and this is an area that takes some work. Because these galaxies approach magnitude 13, they are best suited to the larger telescope.
Now, let’s go between map and sky and identify both Zeta and Eta Crater and form a triangle. Our mark is directly south of Eta the same distance as between the two stars. At low power, the 12.7 magnitude NGC 3981 sits inside a stretched triangle of stars. Upon magnification, an elongated, near edge-on spiral structure with a bright nucleus appears. Patience and aversion makes this “stand up” galaxy appear to have a vague fading at the frontiers with faint extensions. A moment of clarity is all it takes to see tiny star caught at the edge.
Tuesday, May 31 – For early morning observers in the Middle East, you can enjoy an event as the Moon occults Psi 1 Aquarii. Please check this IOTA webpage for details in your area. For all observers, have a look this morning before dawn to see a very pleasing pairing of the waning Moon and Mars, but if you live in southern Africa or South America, you see this as an occultation! Please check this IOTA webpage so you don’t miss it.
Tonight’s study object, 12.7 magnitude NGC 3956 is about a degree due south of NGC 3981. When first viewed, it appears as edge-on structure at low power. Upon study. it takes on the form of a highly inclined spiral. A beautiful multiple star, and a difficult double star also reside with the NGC 3956 – appearing almost to triangulate with it. Aversion brings up a very bright core region which over the course of time and study appears to extend away from the center, giving this very sweet galaxy more structure than can be called from it with one observation.
Wednesday, June 1 – Our galaxy for tonight is a little more than two degrees further south of our last study. The 12.8 magnitude NGC 3955 is a very even, elongated spiral structure requiring a minimum of aversion once the mind and eye “see” its position. Not particularly an impressive galaxy, the NGC 3955 does, however, have a star caught at the edge as well. After several viewings, the best structure I can pull from this one is a slight concentration toward the core.
Thursday, June 2 – Tonight we’ll study an interacting pair and all that is required is that you find 31 Corvii, an unaided eye star west of Gamma and Epsilon Corvii. Now we’re ready to nudge the scope about one degree north. The 11th magnitude NGC 4038/39 is a tight, but superior pair of interacting galaxies. Often referred to as either the “Ringtail” or the “Antenna”, this pair deeply captured the public’s imagination when photographed by the Hubble. (Unfortunately, we don’t have the Hubble, but what we have is set of optics and the patience to find them.) At low power the pair presents two very stellar core regions surrounded by a curiously shaped nebulosity. Now, drop the power on it and practice patience – because it’s worth it! When that perfect moment of clarity arrives, we have crackling structure. Unusual, clumpy, odd arms appear at strong aversion. Behind all this is a galactic “sheen” that hints at all the beauty seen in the Hubble photographs. It’s a tight little fellow, but worth every moment it takes to find it.
Friday, June 3 – Tonight return to 31 Corvii and head one half degree northwest to discover 11.6 magnitude NGC 4027. Relatively large, and faint at low power, this one also deserves both magnification and attention. Why? Because it rocks! It has a wonderful coma shape with a single, unmistakable bold arm. The bright nucleus seems to almost curl along with this arm shape and during aversion a single stellar point appears at its tip. This one is a real treat!
While out tonight, stay on watch for the peak of the Tau Herculids meteor shower. The radiant is near Corona Borealis. We will be in this stream for about a month and you can catch about 15 per hour maximum. Most are quite faint, but sharp-eyed observers will enjoy it.
Saturday, June 4 – Tonight let’s look to the sky again and fixate on Eta Crater – our study lay one half degree southeast. The 12.8 magnitude NGC 4033 is a tough call even for a large scope. Appearing elliptical at low power, it does take on some stretch at magnification. It is smallish, even and quite unremarkable. It requires good aversion and a bit of patience to find. Good luck!
Sunday, June 5 – The last of our studies resides by a star, one degree west of Beta Corvii. In order to “see” anything even remotely called structure in NGC 4462, this one is a high power only galaxy that is best when the accompanying star is kept out of the field as much as possible. It holds a definite stellar nucleus and a concentration that pulls away from it making it almost appear barred. On an exceptional night with a large scope, wide aversion and moments of clarity show what may be three to four glints inside the structure. Ultra tiny pinholes in another universe? Or perhaps an unimaginably huge, bright globular clusters? While attention is focused on trying to draw out these points, you’ll notice this galaxy’s structure much more clearly. Another true beauty and fitting way to end this particular study field.
If you’re just in the mood to skywatch, the stay up a little later to catch the Scorpiid meteor shower peak. The radiant will be near Ophiuchus and the fall rate is about 20 per hour with some fireballs.
The constellations of both Crater and Corvus hold many, many more such fine galaxy studies. Perhaps another year we shall hunt them all down, eh? But for now, our eyes are on Virgo for next week’s new Moon study. I look forward to the galaxy fields again, but not half as much as I look forward to taking you there. Until next week? May all your journeys be at Light Speed… ~Tammy Plotner