11:30 p.m. 24 March 2004 PST (2004–03–25–0730 UT)
What with one thing and another—it's been a pretty sick winter over at our household, for one—I haven't been out in a long time. I decided to go out for a quick looksee, and it turned into a moderate session, about 50 minutes.
It was a joy just to collimate the scope again, or to have a reason to. The last two weeks, ever since I purchased a pair of Canon 10x30 IS binoculars, have been cloudy at night (although some days, naturally, have been clear until dusk). Seeing was subpar, but I'll take it.
My first target was Jupiter. Detail through the seeing was subdued, but I think I was able to make out two festoons trailing from the NEB, especially as they seemed to be turning in the right direction. One was right on the central meridian, and the other followed it by perhaps 30 degrees or so. I also noticed that in contrast to previous years, the NEB and SEB were roughly the same thickness and color. I could see no sign of the NTB, which I've seen on many occasions in the past.
Ganymede and Europa were close to one another, with Ganymede very clearly brighter and larger than the other. Io was on the other side, about an equal distance away from Jupiter, while Callisto was far away on the same side as Ganymede and Europa, out of the field of view at 200x.
Given the seeing, I tried for M65 and M66. The limiting magnitude to my eyes was about 4.6, a bit worse than average. Since the last time I wrote an observation report, I've added stars to magnitude 11.5 to PleiadAtlas, and I needed them. For whatever reason (perhaps some high haze, which I could barely see), I had a lot of trouble with these two galaxies. M66 was barely discerned, and showed a hint of elongation in the north-south direction, but try as I might, I couldn't make out M65.
After that, I felt I should get an easier target, so I found my way to M53, one of my favorite globulars, in Coma Berenices. This object was best viewed at about 80x, and I was able to see some faint structure in it, with arcs of stars branching out to the south, northwest, and a faint one to the east or northeast.
2:50 a.m. 25 April 2004 PDT (2004–04–25–0950 UT)
That date is not a typo. My time outside with Opus has been limited quite a bit lately, mostly because of the kids, but also because the usual California "June Gloom" came by a few months early this year. But that seems to have passed us by for the moment (knock on wood, plastic, multi-coated optics, anything I can get my hands on). I had to sit with the younger one to get him to go to bed, and unfortunately, his bed is so comfortable that I went ahead and fell asleep, too.
It was about 2:15 before I woke up again. I immediately considered going out for a session, but I wasn't sure my body was up to it. I read my e-mail and news as a temporizing measure, and by the time I finished (putting in a fairly lengthy post, as I recall), I was sufficiently energized to dig out the stuff.
I now leave the telescope entirely set up in the garage (cleared out enough space for that, at least), and all I have to do is pull it out to the patio, get my chair, take off the four covers (front and rear of the scope, front and rear of the finder), slip in an eyepiece (32 mm Plossl to start with), and I'm off. I didn't bring an atlas or planisphere; as is my usual tactic now, I just bring my Palm, and do all my star-hopping from there.
My first target for the night was M27, the Dumbbell Nebula. I didn't spend much time with it at first, just wanted to make sure I could still find the darned thing. It's a sign of how late I was up that this object was already reasonably high up in the sky. I decided I'd come back for this later, and went on to M57, which I also just took a quick glance at.
Then to M4, the famous globular near Antares, in Scorpius. I think it's pretty amazing that I once couldn't see this at all (possibly under better conditions, but it's hard to compare); not only can I see it now, but even from home, the well-known north-south bar is fairly easily visible. What's more, I can tell that the bar is a bit off north-south—more like a bit north-northeast to south-southwest.
At this point, I decided to put in my reducer/corrector, which I had left off during last year's Mars apparition. My first target with the reducer in was Stock 1, a large, sparse open cluster close by Albireo. Under moderate light pollution (to my eyes, the ZLM was about 4.7), this cluster is only somewhat detached from the background stars, with a slight density gradient toward the center, where there are some 10 to 15 stars of magnitude 8 or 9 arranged in a thick V pointed toward the east. Later, I tried this cluster with the 10x30 binoculars, and it's definitely more attractive through those.
A bit more interesting is NGC 6823, a medium-rich open cluster about 2.5 degrees to the southeast of Stock 1. It's much smaller, and has only three or four stars that are easily visible, but I kept getting the sensation of a secondary layer of stars in the 11th-magnitude range, or maybe a little dimmer, lingering just beyond. I didn't verify that, since I would have needed to bring out Snuffy for that, and I didn't have the energy for that.
I also tried, without much expectation for success, for NGC 6820. This nebula has long thought to have been identified with a large arc of gas and dust in which NGC 6823 is embedded, but as Bill Ferris has noted, the NGC description does not match this object. It seems better aligned with a small reflection or emission nebula about a quarter degree to the southwest of the open cluster. This object was definitely invisible to me without a narrowband filter. With the filter, there might just possibly have been somethere visible there, but I certainly couldn't say for sure. I'll have to write it down as a negative observation.
I tied up the session with a glance at M11. The Wild Duck Cluster was then in the southeastern sky, which is still well within the light dome cast by Los Angeles—even at that time of night. But I was able to find lambda Aquilae, and then through the finder, it's a simple star-hop around a small crown-like asterism joining lambda to the northern stars of Scutum, and lying in wait at one corner of the crown is M11. The cluster takes magnification well in a small telescope, and I could best see the cluster at around 100x or so, the eighth-magnitude star sitting just off the corner of the square-edged fan.
After packing up the telescope, I came outside with the binoculars and looked up (besides Stock 1) Albireo and M27. I forget how enjoyable a way it is to relax and look up in the sky while sitting comfortably.
12:30 a.m. 26 April 2004 PDT (2004–04–26–0730 UT)
Yes, it's true: observing two nights in a row. I bet it's been a long time since I've done that with Opus.
With the reducer/corrector still in place from last time, I got right to work. I had forgotten temporarily that I wasn't up as late as I had been the previous night, so I wasn't going to be able to get a good look at Cygnus yet. (I have a garage that blocks some of the eastern sky.) So I decided to track down M13.
There's enough light pollution that finding the Keystone of Hercules is a non-trivial task. This night, I found it by first locating Arcturus, then Izar (epsilon Bootis), then Alphecca (alpha Coronae Borealis). The Keystone is then about halfway between Alphecca and Vega. M13 is about two-thirds of the way up the western side of the Keystone, which makes it pretty easy to find. It's barely visible in the finder, but a piece of cake in the eyepiece.
This is another one of those objects that takes high power well. I found my best view at about 80x. In this small an aperture under the constant light pollution, the famous streamers of stars are reduced; I cannot see them with direct vision. But seeing them only with averted vision gives them a sort of evanescent quality. For some reason, I find I have to constantly recalibrate by employing direct vision to get a sort of "baseline" view of the core of M13, and then a few seconds of averted vision gives me the differential. After a while, that stops working, and I have to lather, rinse, repeat until I build up a mental image of what's going on.
That constructed image shows to my mind's eye a sort of bonfire-like
appearance, with the flames rising toward the northeast. I was reminded
of the Chinese character for fire, which is indeed derived from a
bonfire pictogram. It's interesting in a way, since M13 does glow with
the fire and light of nearly a million stars (or more, depending on
what you count as a star).
Then I retraced my steps back toward Izar, or Pulcherrima, as it was called once by an astronomer who was struck by its beauty (it is Latin for "most beautiful"). The star is a notable double in Bootes, a yellowish primary paired with a dim blue-white secondary. The seeing was only good enough to glimpse, on occasion, the secondary sitting just outside the first diffraction ring of the primary. The collimation was a tad off, but correcting this didn't make the pair any easier to split. It was clear that turbulence was the limiting factor.
Next up was the nearby star, R Coronae Borealis, the archetype of a class of "inverted" variables that are usually at some baseline magnitude, but on occasion throw out a belch of carbon-rich dust and dim by several magnitudes. In the case of R CrB, the baseline magnitude is about 6, but it can dim by as much as 8 magnitudes. Usually, the drop is about 6 magnitudes. It is spectral class C0, indicating that it is a relatively warm carbon star. I expected to find it a bit redder in the scope. I could barely tell that it wasn't white, as opposed to mu Cephei (Herschel's Garnet Star), which I also looked at; that star was noticeably reddish-orange, as its name promises.
I didn't expect to stay out as long as the previous night, so I brought things to a quick close by looking for M68, then sinking quickly into the southwestern skies. This globular cluster, in the southern half of the small but prominent constellation of Corvus the Crow, is large and sparse, making it difficult to see even in moderate light pollution, and I could barely find it. In contrast to M13, there was never any question of seeing any detail in this object (as I might have considered if it were higher in the sky); the challenge lay simply in detecting it in the first place.
As with the previous night, I packed up the scope, but then spent another 15 minutes or so just skimming through the sky with my binocs. It really is a joy to trundle amongst the stars with an image-stabilized pair of binoculars; I could genuinely imagine doing as Alcock did, memorizing the star patterns across the sky, in hopes of one day finding and discovering a comet or a nova. I was able to see M13 surprisingly well, considering the aperture, and found IC 4665 off from beta Ophiuchi (I'm not really keen on this sparse open cluster), and I think I just barely glimpsed M81 and M82 starting to set in the northwestern sky. I also tried to make out M51, but although I found exactly the right spot (it marks the fourth corner of its own little Mini-Keystone), I just couldn't see it. I suppose it goes without saying that I couldn't make out any signs of spiral structure, either!
10:45 p.m. 27 April 2004 PST (2004–04–28–0545 UT)
I started this evening with an observation of Melotte 111, better known as the Coma Berenices Star Cluster. (Not to be confused with the Coma Berenices Galaxy Cluster, which is much, much further away.) This cluster swamps the field even at the lowest power available, 25x with the 32 mm Plossl and the focal reducer in place. It's one of the few objects that makes me want to go out and get the 24 mm Panoptic.
I then focused my attention over to NGC 4565, Berenice's Hairclip, an edge-on spiral galaxy located within or just outside of Melotte 111, depending on where you put the boundary. This galaxy is not tremendously obvious under light-polluted skies, but it is detectable as a thin sliver of light. There was no sign of the dark gas cloud that divides the sliver in two, as is evident under dark skies.
I swung Opus over to the Moon, which was at about first quarter, hoping to see some signs of detail in Plato (one of my favorite lunar targets). Alas, the seeing was abominable, and no sign of the little craterlets could be seen. This was confirmed when I took the telescope over to Jupiter. With the 6 mm Radian (130x) in place, I could make out nothing but the two main cloud belts. I decided I would wait until the scope was a bit better acclimated.
In the meantime, I moved over to Izar, aka Pulcherrima, aka epsilon Bootis. This double's separation isn't especially tight—I think it's about 3 arcseconds—but the magnitude difference between the golden primary and the bluish secondary makes it a bit harder than it would be otherwise. At this point, I found that the scope was suffering from a bit of miscollimation, which might wash out some of the smaller detail. I tweaked it, and was rewarded with a more distinct split of Izar than I had had before.
Thus encouraged, I put the telescope back on Jupiter. The view was a bit better now, but not much so. Still, I was able to see two more details that were invisible before: festoons located at about 60 and 30 degrees preceding the meridian. However, they were never the sharp, clear objects that they've been in previous observations when the seeing was much better.
Copyright (c) 2004 Brian Tung