On 21 and 22 August, 1998, I took Harvey, my white Celestron 14, to
Fremont Peak State Park, near San Juan Bautista, California. We had
quite dark sky, though the fog below did not get dense till rather late
on the second night. Seeing limited useful planetary magnifications for
the big Celestron to about 250x.
I continued the dual observing program -- planetary nebulae and
galaxy groupings -- that I described in a previous posting. On the two
nights combined, I logged over 30 new planetaries -- that's new to me,
of course -- and some 80 new galaxies. Most of the planetaries were in
the region where Scorpius, Sagittarius, and Ophiuchus border on one
another -- quite far south for 252x (Meade 15.5 mm Research-Grade Erfle
eyepiece -- the only eyepiece I used on the C-14 all weekend), even if
the seeing had been good. Most were rather small, too -- less than ten
arc-seconds in angular size. From my observing latitude near 37 N,
these planetaries get no more than 30 degrees above the horizon, and I
was not always observing as they crossed the meridian, either.
Thus the seeing was frustrating. It is odd to think of deep-sky
observation being affected by seeing, much less limited by it, but it
was. Most of the time, stars themselves were blurred out to several arc
seconds diameter, making everything in the field look like a planetary
nebula. For many detections, I would have to wait patiently, till a
moment's good seeing made star images shrink to points, and see if
anything in the field remained a disc. Success at that strategy,
however, required the telescope be well focused, and in poor seeing,
good focus is difficult to achieve -- in such conditions, the only
symptom of slight soft focus is that moments when everything gets crisp
never occur. It can take a long wait to decide that is the case, and
then, which way do you turn the focuser to make things better? Grrr!
Some times I would use "blinking" to verify stubborn targets,
interposing an Orion Ultrablock filter between my eye and the eyepiece,
to see which of the objects in the field did _not_ diminish in
brightness, or at least, did so but little. That works with varying
degrees of success on different objects: Sometimes a small planetary
will have its own luminosity dominated by the star from which it has
been emitted, and the light of the combination is affected by the filter
much as any ordinary star. If the planetary is too small to resolve as
a disc, it is undetectable with my equipment, even if bright.
Sometimes also I would thread the filter into a two-inch extension
tube, and observe through it. A few extended planetaries were too faint
to see otherwise, particularly as the area I was observing sank toward
the glow above Salinas, California.
In poor seeing, there is little detail to record in such small
objects. My observing notes consisted mostly of remarks about whether a
planetary was diffuse or appeared stellar (in which case I would have
had to detect it by "blinking" to log the observation), and -- if
diffuse -- whether I could detect any sign of a central star. For only
one object did I record a noticeable shape, and even then the best I
could do was to say that it was "irregular".
I did detect an object that has been of occasional interest among
internet amateur astronomy enthusiasts; namely, "Gomez's Hamburger".
This object was not on the atlas I was using (_Millennium_Star_Atlas_,
very useful because its 11th-magnitude stellar limit provides plenty of
stars for star-hopping), so I had to plot its position myself, but at
the coordinates of 18:09.2 -32 10.0' (epoch 2000), I spotted a tiny
blur. There was no hint of any of the detail which gave the object its
name, nor any hope of increasing magnification to look for it.
According to Jay McNeil's notes, which I use extensively, Gomez's
Hamburger is cataloged as PK 359-6.2 and also as IRAS 18059-3211.
Another interesting planetary was PK 6+2.5, which I tracked down in
the very confusing background field provided by open cluster NGC 6469,
at approximately 17:53 -22.3 (epoch 2000). I am not sure whether the
planetary is physically associated with the cluster.
Observing galaxy groups is very humbling. What an eerie experience,
to wander around in a square degree that contains a half dozen NGC
galaxies, trying to identify them! The field seems full of ghosts --
tenuous, half-seen agglomerations of starlight, trying to be galaxies,
torturing the mind of the observer. Yet they are not ghosts -- they are
there. The little groupings I look at are essentially all real,
gravitationally-bound physical associations of galaxies, and the NGC has
only skimmed the bright ones. There are always more. The C-14 will
work galaxies fainter than those charted on the _Millennium_ atlas, so
the task is not merely finding those charted, but identifying which of
the multitude that are present met the celestial cartographers' criteria
for being bright enough to plot.
Some people make an observing program out of trying to look at all
the non-stellar objects on a given set of charts. I hear there are sets
of _Uranometria_2000.0_ in which page after page is bespeckled with the
erratic tracks of a "highlighter" marker, neatly superimposed over the
variety of ovals and variously patterned circles that denote deep-sky
objects. Yet once I saw a nicely prepared chart of the entire sky, and
on it was superimposed a widespread, lacy, filamentous network, as if
some berserk cosmic spider had strewn a dense feathery web across the
heavens. It seemed to have structure -- it did not look random -- but
there was no repeating pattern. What it was, was a carefully plotted
distribution of the brightest _million_ galaxies known.
I remember reading a science fiction book by Diane Duane, in which a
species of intelligent arachnid-like beings believed in a web-spinning
divine creator whom they called "the Architectrix". Seeing this display
was enough to make me wonder if they were right. In any case, I have
often wished for a handful of printouts, to pass out to those of my
fellow deep-sky observers who habitually highlight their charts. It
would be fun to watch grown men and women cry.
I did look at a few other objects. Jupiter and Saturn were both
frustrating at the same 252x magnification. I am not an experienced
planetary observer, but I know the C-14 is a quite good planetary
telescope when conditions are right. They were not right on these
nights. The fact that I could use the same eyepiece for planetary
observation that I had been using for deep-sky work, testifies that
seeing kept the C-14 just loafing as I looked at the big gas giants.
Saturn showed one broad band on the globe, as well as the Crepe ring and
the Cassini division, and several moons.
Jupiter was even more of a tease: In moments of clear seeing, I
could see scalloping at the edges of many of the bands, as well as
detail within both dark bands and bright zones. I had the feeling that
I was looking at weather rather than just climate. (How odd that
looking at clouds down from the top is astronomy, whereas looking at
them up from the bottom is merely frustration. Oh, well, perhaps we
would think differently if it was the clouds of Jupiter whose bottoms we
were seeing.)
On both nights, I finished setting up before the end of twilight,
and spent a few minutes then reviewing bright objects. A C-14 at 252x
resolves most Messier globular clusters -- I went through half a dozen
in ten minutes or so -- and blows big open clusters wide open, so much
so that there is a "can't see the forest for the trees" problem. If the
Messier surveys I have done with 50 mm aperture have been most rewarding
with respect to difficulty of achievement, then the one I long ago
finished with this C-14 was most rewarding with respect to spectacular
displays. Aperture wins, and how!
At one point, I noticed that some planetaries I was chasing lay not
far from a non-NGC globular cluster, Terzan 9, so I star-hopped over and
found the nondescript small blur. An NGC planetary, NGC 6445, the
so-called "Little Gem", lay near another target, so I reviewed it. I
had observed it once before with the C-14, at 315x, and more recently at
37x with my 55 mm Vixen fluorite refractor. In the larger instrument,
on both occasions, it appeared as an irregular annulus; in the smaller,
it was featureless.
When people wandered by, I generally asked if there was anything
particular they wanted to see. Besides Jupiter and Saturn, some friends
wanted to look at NGC 7009, the "Saturn Nebula", so I located it. This
object is sufficiently Saturn-like that one guest actually thought it
was Saturn, and wondered why it was so out-of-focus! The C-14 revealed
the "ansae", the extensions of this oval planetary that look like
Saturn's rings seen nearly edge-on, and I think that one or two
observers may have gotten a hint of the central star, which is easier in
better seeing.
I also used some other instruments. Recently I bought an Orion
14x70 "Little Giant" binocular -- one of the last of that model, for the
new ones are 15x70 -- but had to exchange it because of defective
optics. In the small hours of 23 August, after I had put Harvey to bed,
I tried the replacement, which was from an earlier lot of 14x70s. Its
optics are much better, and the binocular is startlingly capable.
After some quickie optical testing I took a look at the Double
Cluster, h and chi Perseii, and found them well resolved. Then I looked
at the Veil Nebula. There was fog in on the coastal plain west of the
Peak, but some artificial lighting was visible through it, so I did not
think it was very dark. I may have been wrong, however, or perhaps the
sky above was exceptionally transparent, for I immediately located not
only the eastern and western arcs of the Veil, but also the long, skinny
triangle that lies between them. Next I easily found both the North
American and the Pelican Nebulae, and traced M31 to a full width greater
than the binocular's four-degree field.
Seeking additional challenges, I tried to remember where the
California Nebula was, and found a long, faint patch of glow at about
the right place. I wasn't sure of the position, but an observer with
one of the huge VIxen binoculars -- a 30x125 -- was also looking for it,
and at the same place where my glow was. I was able to hold the
California Nebula more easily in my 14x70 than in the larger instrument.
I suspect the difference was the slightly larger exit pupil of the
14x70, coupled with the fact that it was easier for me to move the 14x70
-- and in fact, difficult not to. The glow was more easily seen by
scanning or moving the instrument; my eye could more easily detect a
change in a low light level than an absolute low intensity. The larger
field of view at the lower magnification may also have helped.
Many people think the California Nebula cannot be seen without some
kind of light-pollution filter, but that clearly isn't so.
Continuing with the 14x70, I logged NGC 7331, which is often
difficult in binoculars because of its small angular size, and logged a
few more Messier objects for my Messier survey with this instrument.
The farthest east of these were M42 and M43, seen low in the southeast,
as Orion threw one mighty leg over the far horizon.
An observer near me was looking at the Pleiades at low magnification
-- 36x in a Celestron 8, and 15x in a Ranger. I overheard him tell a
companion that the Pleiades did contain nebulosity, but that he had
never seen it -- all the stuff in the field that looked like nebulosity
was a mere consequence of dirty optics. At that point, I asked for a
look. It is indeed possible to confuse scattering from dirty optics or
dew (not a problem on these nights) for nebulosity near bright stars,
but what he was seeing was not symmetric about the stars, and held
position when I moved the telescopes slightly. His equipment was giving
lovely views of the Merope Nebula, and of a good deal of other Pleiades
nebulosity as well. When I pointed out what he was seeing, he remarked
that he simply hadn't known what to expect.
Near the permanent observatory that houses a 30-inch Newtonian, a
seven-inch Astro-Physics EDT refractor and a sixteen-inch Meade LX200
were set up ten meters apart, both viewing Saturn. I am well familiar
with this particular refractor, but though I have observed with smaller
LX200s often, I had never had a look through Meade's high-end monster.
Unfortunately, the seeing was not up to a real comparison. Both
instruments were running at two or three hundred diameters. The
refractor was hit less hard by seeing than was the 16-inch: The smaller
instrument gave aesthetically pleasing views during a higher fraction of
the time. It appeared to me that the big Meade matched the refractor
during the brief moments of clear seeing, but those were infrequent, and
I suspect that higher magnification would have revealed that the
seven-inch was also at least a little bit restricted by seeing. It
would be interesting to have these instruments side by side on a good
night.
Some times the fun parts of a star party are not observations but
conversations. On one of these evenings, I had a long chat with a
person who had spent the better part of a lifetime involved in
astronomy, both as an astronomical educator and as an amateur, in
several countries. He had many stories to tell. He had owned a C-14
before -- an old model which, like Harvey, had come equipped with an
orange tube and Celestron's big fork mounting. We chatted a little
about techniques of setup and use. His present observatory, however, is
equipped with ten- and twelve-inch Maksutovs, and with an 8-inch
AstroPhysics EDF refractor. (I haven't mentioned his name just because
I dislike publicizing the location of expensive equipment.) He uses the
latter instrument primarily for double-star observations, and measures
position and separation with a filar micrometer. I was most intrigued
-- good double-star micrometers are hard to find.
So now, those of you who live near the San Francisco Bay area will
have additional opportunities for green-flash observations, of flares of
jealousy from the several local observers whose Astro-Physics refractors
are now revealed to be mere puny, inconsequential, seven-inchers. Oh,
well, refractors do make good finders...
--
Jay Reynolds Freeman -- freeman at netcom dot com -- I speak only for myself.
