by Albert Highe
As I mentioned in a previous post, about a dozen people showed up at Dinosaur Point. Seeing was decent early on. During brief periods of steady seeing, Jupiter showed quite a lot of detail at 210X. I could see two very dark brown barges. Five stars were visible in the Trapezium. The sixth was visible intermittently. The transparency was very good to outstanding.
The temperature dropped to the low to mid-50's and the RH climbed to about 80%. We had absolutely no dew until about midnight. Then about 2/3rds of the observers packed up for home. At about 12:15AM, some soup began to spill over Pacheco Pass. Although about 3/4 of the sky still looked good, the humidity quickly climbed into the high 80's, dew began to form, and the wind picked up to 15-20. So everyone else packed up and left by 1AM.
| Equipment | 12.5" f/5 ultralight, 14mm Radian, 7.5mm LE |
|---|
As I've reported earlier, as a consequence of working my way through the Sky Atlas 2000, I've observed all of the objects on the Herschel 400-I list and the majority of those on the Herschel 400-II list. I still haven't decided on my next major observing project. So, tonight I focused on some of the remaining Herschel 400-II objects on my list.
As I worked my way through obscure open clusters and galaxies, I quickly was reminded why I dislike the Herschel 400 (and most other) lists. Does anyone know what criteria were used to create them? Most of the objects hold no special interest for me and I dislike making huge jumps across the sky to find yet another uninteresting object.
So, rather than check off a large number of the Herschel objects, I used them to establish beachheads in selected areas of the sky. After finding one of the objects on the Herschel list, I consulted "The Sky" for other objects nearby. This proved to be an interesting, challenging, and rewarding approach.
NGC2415 (mag 12.9, 0.9') Just a few degrees from Castor, over the border into Lynx. A bright circular fuzzball. Sits next to a 9th magnitude star. Holds up to magnification well. Less than 0.5° away, in the same f.o.v. of my 14mm eyepiece, I could detect something. I bumped up the magnification to 210X with my 7.5mm LE. The Sky indicates three very faint and very close galaxies: UGC3937 (14.1, 2.0'X0.5'), UGC3934 (14.8, 1.0'X0.8'), and MCG6-17-22 (15.6, 0.4'X0.2'). It was quite easy to make out UGC3937 as a highly elongated oval using averted vision. I could just detect UGC3934, but could not convince myself I saw MCG6-17-22.
NGC2493 (13.0, 1.7') Another bright fuzzball galaxy in Lynx. It has a noticeably brighter, small core. The Sky indicates two very faint galaxies 2 and 4 arc minutes away: NGC2495 (15.8, 0.4'X0.2') and CGCG207-17 (15.7). These are definitely challenge objects for my 12.5". But I had just cleaned my optics, the transparency was excellent, and the 7.5mm LE has outstanding light throughput. I studied the area at 210X for several minutes with averted vision. CGCG207-15 jumped out at me first. I could eventually hold it with averted vision about 50% of the time. After a while NGC2495 appeared about 30% of the time. If these magnitudes are correct, they set a new record for this scope.
NGC2756 (13.0, 1.8'X1.2') The Herschel list now directed me to leap into Ursa Major. NGC2756 is a fairly small, slightly elongated oval, with a gradual brightening toward the center. The Sky indicated a faint companion, CGCG264-68 (15.8, 0.3'X0.2'), just 3' away. I could hold this small galaxy with averted vision about 75% of the time. I then star hopped at 210X the 0.3° southward to a distinctive pair of 9th magnitude stars. Forming a triangle with them was CGCG264-64 (15.3). Although brighter, I found this galaxy tougher to hold. I could detect it about 30% of the time. Retracing my steps in the eyepiece, back to NGC2756, I then continued northward 0.6° to the galaxy UGC4807 (14.4, 1.0'X1.0'). This galaxy was somewhat difficult because of the collection of "bright" 9th and 10th magnitude stars in the f.o.v. But with continued study, I could eventually hold it with averted vision. Continuing northward another 0.3°, I found the galaxy NGC4800 (14.6, 1.6'X0.5'). It sits in a line with a 8th and 9th magnitude star. I also could hold it with averted vision.
I had some doubts about seeing the 15th magnitude galaxies. However, I saw so many where they were supposed to be, and 14th magnitude galaxies were relatively "easy". So, I suspect that I might not have been imagining them. The transparency really was that good.
Has anyone observed NGC1990? The type of object is not indicated on my Herschel list. The Sky says it's a very large nebula surrounding the bright central star in Orion's belt. I could not detect it.
I finished the night with a quick look at some bright Messier's. When conditions are good, I like to study familiar objects at higher powers. M81 was a particular treat. I usually think of this galaxy as a rather featureless bright oval and quickly jump to M82. At 210X, I could see the outer halo of M81 extend well beyond the f.o.v. It was nearly as wide as the eyepiece f.o.v. I could trace its outline by sweeping across the field. It appeared that there is also a brighter inner oval, and then the very bright, small, dense core.
M82 was full of dust lanes and bright knots. This is undoubtedly the best view of this galaxy I can remember. I studied it for quite a while.
And M51 nearly filled the f.o.v. The spiral arms were distinct. I could detect the faint bridge of starstuff to its companion, NGC5195, as well as detail in its disturbed core.
Despite the threatening weather early on, the night turned out to be an exceptional, pleasant surprise.