by Randy Muller
I was able to take advantage of the continuing clear weather pattern last night, February 10, and go out into my backyard to take an extra-galactic journey in my quest for Herschel objects. Streaks of clear weather are not common in the winter here, so I felt I had to take the opportunity as it came.
I did not really feel like observing, because I had stayed up late and lost sleep the night before, but I was excited and happy to be outside under the stars again. There is just something about standing under the stars and searching for and seeing the faint wispy delicate tendrils of light that are galaxies.
I also sometimes wonder how many beings in those galaxies are looking back at me? How many were looking back at me last night? What does our galaxy look like to them? Is it cool looking? Average? It must make quite a nice pair with Andromeda from very far away.
The conditions were marginally worse than they were last night, and there were thin high clouds crossing and loitering in the southern sky, so although it is a region of fairly severe light pollution, I stayed in the north this night.
I pushed up my self-imposed magnitude limit from last night by half a magnitude. When I tried to find a mag 11.2 galaxy (NGC 2742), I failed. I've had nights where I've been able to see down to 12, but those are extraordinary and do not occur often in my backyard. Tonight was a slightly above average night for the sky.
I resumed the hunt in Camelopardalis, the Giraffe. I've never recognized any stars in this constellation before, and I recognized only one tonight. It's composed mainly of faint stars, and was seemingly designed in 1614 by Herr Bartschius just to take up some blank space in the sky.
This area was above Polaris, the north star, when I was looking at it, and it wasn't too far away from the north celestial pole.
After using M42 and M109 again to assess the sky conditions (seeing was marginally worse [still 6 stars in the Trap, though], and transparency was about the same), I began to engage my quarry: Herschel 400 galaxies.
NGC 2403, almost 25 degrees directly above Polaris, was an easy-to-find enormous oval galaxy, diffuse but fairly bright (mag 8.5). There were two foreground stars aligned with the axis of the oval, that made it interesting to look at.
NGC 2655, a round galaxy with a concentrated, but non-stellar center, was much closer to Polaris and dimmer, but not 'faint' (mag 10.1). It was also sitting prettyily almost between two foreground stars.
I then crossed the boundary into Ursa Major, the Big Bear.
NGC 2950 was very easy to find, being about 1 degree away from Upsilon Ursae Majoris, which is the more southern of the two stars I use as pointers (more or less) to M81 and M82. (The other is 23 UMa). This is a small, round, bright (mag 10.9) galaxy with a concentrated and stellar center.
NGC 2768 lay a bit further away from these pseudo-pointers. It was a 'medium bright' (mag 9.9) small oval galaxy with a diffuse center.
At this point, I took a small break to look at the really bright pair of M81 and M82. These galaxies are huge and bright compared to the others I was looking at, and are always breathtaking to get in a single field of view. M81 is a nice, bright oval, and M82 looks like a tortured roll of newspaper. M82 is very odd looking and is a premier example of an irregular galaxy. In photographs, it looks like it's exploding.
I also began to encounter some problems with dew: The eyepieces of my binos would dew up when I brought my eye too close to it, or if I looked for any length of time.
While in the neighborhood, I also rounded up NGC 3077 and 2976. I had 'discovered' 3077 by accident the first time I was at a dark site on May 23 last year. It seemed quite bright back then. This night it was quite a bit harder to see than M81. Although it was very large, 2976 was almost not there, it was so diffuse.
About 3 degrees to the west of this area I resumed the chase with NGC 2787. It was a very small, faint (mag 10.8) round galaxy with a non-stellar center.
Near the left hind paw of the Great Bear was NGC 3184. It was very easy to find (being right near Lambda and Mu Ursae Majoris, a.k.a., Tania Borealis and Tania Australis, respectively, or "Al Kafzah al Thaniyah" ["The Second Spring of the Gazelle"] together), but very difficult to see, being large, round, diffuse and very faint (mag 9.8).
The final object for the evening was NGC 3310, a small, round, 'medium bright' (mag 10.8) galaxy with a non-stellar center.
At this point, I ran out of bright galaxies in the north, and high, hazy clouds were thickening in the south, so I quit.
The magnitudes of these galaxies are interesting: They only vaguely reflect how easy or difficult something was to see. (Having a stellar or concentrated center helps the detection a lot.) Not only do these magnitudes vary with what I perceived, they vary between sources of data, sometimes by as much as nearly a full magnitude.
Once again it was great to be out under the stars, chasing down galaxies in the landscape of the sky.
| Date | February 10, 1999 9:45-11:30pm (0545-0730 Feb 11 UTC) |
|---|---|
| Location | Backyard, in Roseville, CA 121W 16', 38N 44' |
| Instrument | Orion DSE 10" f/5.6 dob-newt |
| Oculars | 10mm, 26mm plossls |
| Seeing | 8/10 very steady, a bit of fuzz |
| Transparency | 8/10 very clear, some clouds |
| Visual limiting mag | 5.0 |