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(IAAC) Obj: Hickson50, Abell2065, NGC6227, NGC4676 (The Mice), M104, M57 and more - Inst: 82" Ritchey-Chretien,F13.1,Equatorial
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Observer: James Anderson
Your skills: Intermediate (some years)
Date/time of observation: 05-02&03
Location of site: Mt Locke, TX (Lat 31N, Elev 6700)
Site classification: Rural
Sky darkness: >9 <Limiting magnitude>
Seeing: >9 <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: 82" Ritchey-Chretien,F13.1,Equatorial
Magnification: 497, 847
Filter(s): None
Object(s): Hickson50, Abell2065, NGC6227, NGC4676 (The Mice), M104, M57 and more
Category: Other.
Class:
Constellation: many
Data: mag size
Position: RA : DEC :
Description:
This may be a bit muddled, but my notes ended up as a wad of note pad
paper stuffed in my pocket. Here goes. J.A.
An astounding night with the 82-inch McDonald Observatory telescope:
Aperture may not be everything, but the rest doesn’t count for much.
A few days before leaving for the Texas Star Party, most registered
attendees got an e-mail from Bill Wren, of the public affairs dept. at
McDonald Observatory:
-Want to observe on the McDonald 82" during TSP?
-28 people will be allowed to observe using the 82" telescope on
Tuesday night of TSP. The cost is $100 per person. The money will go
to the new Visitor Center that is being built. This will be limited to
the first 28 people. Tickets can be purchased any day at the Visitors'
Center prior to 5:00 PM on Tuesday.”
That seemed like kind of a nice idea—I’d never observed through
an 82-in. telescope before, and offhand I don’t know of anyone else
who has either. The e-mail was forwarded on to Jim, who was going
along with me, and he didn’t argue much either.
So . . . off we go to the TSP. 28 hours later and 1780 non-stop miles
out of Durham, NC definitely the worse for wear, our first stop was
not the Prude Ranch, but McDonald Observatory’s visitor’s
center, where we plunked down our $100 each. We were about 12th &
13th on the list. Then we headed on down the mountain to the Prude
Ranch, the TSP—and a shower.
We found out that the visual session owed its existence to McDonald's
observatory pecking order: since the commissioning of the Hobby-Eberly
telescope, projects have migrated upward. Spectrographic studies on
the 82” moved up to the 104” when some of those projects moved
up to the Hobby-Eberly. This left the 82” somewhat undersubscribed,
so the Visitor’s Center was encouraged to apply for public
observing nights. They were awarded four nights for visual
observing. Our 28-person all-night session was the only all-night
session of the four nights this year, and the first known all-night
visual observing session since the telescope’s commissioning in
1939. It has been decades since the visual back was even
installed. Other visual observing has used the access eyepiece of
whatever instrument was attached to the scope at the time (usually a
spectrograph). In our case the visual back gave full use of the
Cassegrain focus. More on that below.
Come Tuesday, immediately after the evening meal, we left the Prude
Ranch for the 20-mile uphill drive to McDonald Observatory. Not
wishing to be late for the event, we allowed plenty of time for
emergencies—heck, we left early enough that four flat tires and a
meandering herd of longhorns wouldn’t have made us late.
A very strange sight while our group was assembling in the parking lot
at the Visitor’s Center: here we are, miles and miles from much of
anything at all, and down off the mountain comes a shiny yellow
Checker Cab! Of all the things I would have expected NOT to see in the
remote wilds of West Texas, a nonchalant yellow Checker cab, with its
'TAXI' light on top, is way up on the list--barely ahead of a UFO
landing. Maybe it was a UFO, from a planet that admires the design.
Toward sunset we were bussed from the visitor’s center at the foot
of the mountain up to the 82” dome. It took two bus trips, since
the bus only carried 14 passengers—which is probably where they
came up with 28 people in the group. We had an introductory briefing
in the observatory’s library, amidst bookshelves full of
astronomical tomes of all kinds.
The rules for the evening were simple, with emphasis on safety: A
scope that large is, in human terms, unstoppable: if you get in the
way you get crushed—or at least knocked aside. For visual
observing, we were standing on the two hydraulic platforms normally
used for equipment changeout. These may elevate as much as 12 feet
above the observatory floor and lack guardrails in some
places—Gerard de Vaucoleurs was famous for falling down one
particular gap near the south pier, in fact. With 26 people (there
were two no-shows), the observing platforms were definitely friendly,
and there was about a half-hour cycle time between objects while
everyone observed each object. It was a little like one of our
club’s public observing sessions—on steroids.
The scope in question is the Otto Struve 82-inch f13.2 Ritchey
Chretien, built by Warner & Swasey back when telescopes and
battleships shared a very similar engineering philosophy (Otto Struve
was McDonald Observatory’s first director). When it was
commissioned it was the world’s largest telescope, but only for a
few months. Surprisingly, it was equipped with setting circles, which
actually were used in its early days.
The dome floor is two long flights of stairs above ground level, and
is entered through the heated control room, full of all the the remote
controls, readouts and various computers normally used to control the
telescope and its instrumentation. A dome full of visual observers,
with Bill Wren at the controls, along with a graduate assistant
volunteer, had never been done before, so there was a sense of
inventing the procedure as we went along. The dome stayed drafty, and
got fairly chilly by the wee hours.
We observed at the Cassegrain focus with 55 and 32 mm eyepieces (yes,
of course they were Tele Vue Plossls), which gave 496x and 847x
respectively with fields of view of only 6 arc minutes for the 55 mm
and less than 5 arc minutes for the 32 mm. No, we didn’t try a
Barlow—would you have raised your hand and asked? There wasn’t
any worry about bumping the telescope: a body slam wouldn’t wiggle
it. The two itty-bitty finderscopes (mere 8” refractors) were also
available for viewing, and helped to relate what we saw to a more
familiar scale.
The slot was opened as twilight was falling, and the huge scope
(someone said it was noisy enough to be called an LX2000) rumbled to
the first object: Castor, which was easily split. Split? One person
remarked that the gap was wide enough to drive a bus through. As we
were previously warned, the star images were soft rather than pinpoints,
since we were looking through a 2-meter column of air, but seeing was
beautifully steady—in fact, it was the best seeing of the whole TSP
week. The seeing was superb, like 2-3. There was hardly a wiggle and
only now and then. With such a restricted FOV we could not observe
larger objects very well, but we soon found out that even small parts
of large objects were seen in (excuse the pun) a whole new light.
A frequent occurrence during the night, particularly when the
telescope was pointed somewhere near the zenith, was the sense of
unreality when you walked UNDER the telescope to observe: the
familiarity of an ordinary eyepiece mounted in a regular diagonal
seemed completely out of place hanging out of the huge back end.
The next object was the Ghost of Jupiter, which completely filled the
field—not particularly ghostly, either. Next was a galaxy, face-on,
much larger than the FOV. The nucleus was small, almost starlike with
tightly wrapped arms. The contrast was great and the arms did not show
much clumping, rather were a continuous stream of stars (not resolved,
of course). Other observers claimed to see some red emission areas in
the arms, but I could not. It was a magnificent sight!
Then NGC4565, an old friend of an edge-on galaxy, but more than twice
as long as the FOV. The central bulge was relatively small with an
almost starlike nucleus halfway hidden behind the central dust
lane--which was magnificent with very evident mottling. It was sharp
with good contrast, not washed out as in all those lesser scopes we
look through.
Then HICKSON 50. It was quite difficult even in the 82”. I saw
three fuzzies, and maybe some more seen with averted vision. Then
onward to M3! A fine globular filling the field and showing many
yellow and a few reddish stars. The fainter stars looked
blue. Wow--this was something else!
Next, NGC6227, an edge-on galaxy. It appeared mottled without specific
structure with one end being indistinct. There was a bright foreground
star just above and to the west of center. There was no evidence of a
nucleus.
NGC4676: “the Mice,” a pair of interacting galaxies. I thought I
saw three objects, but I later determined that the third object was
part of the upper galaxy. It was in fact, the arm opposite the
encountering arm and the first galaxy.
M104 more than filled the FOV--only about one third of the galaxy was
visible at one time. The scope started centered on the central
bulge. The nucleus was bright, but not at all stellar—definitely
fuzzy. The dust lane was as dark as the background and sharp-edged on
the upper side, with just a faint glow below the dust. Panning over to
the end of the ansas, the dust lane seen in projection seemed to wrap
around the end and continued back toward the nucleus, fading out
behind the central glow–a galaxy in 3D. Changes to the scope’s
pointing were discouraged because of the time required, but this
panning was necessary to get an overview of the galaxy’s
structure. The galaxy’s general halo was not detected even though
it was seen the previous night in the 12”. The detail was similar
in both scopes, and while the 82” showed a much larger scale, it
was surprisingly not brighter.
Abell 2065, a 6 galaxy cluster. I saw 3 definitely 15-17 mag
fuzzies. My eyes are not up to detecting more than 18 mag objects. It
was not very impressive, just faint indistinct fuzzies, no matter how
big the scope.
NGC6543, the “Cat’s Eye” planetary nebula. The inner gas
shell looked like the CBS eye with the interlacing rings of the outer
shells surrounding the inner eye. It was a spectacular view--very
large, filling the FOV and with some pink/reddish tint in the outer
rings in addition to the greenish central area.
NGC6503, edge-on galaxy. Not quite edge-on, about 20 deg tilt, but the
dust lane is really dark with clumps around the periphery. The central
nucleus is pretty much washed out.
M13 completely fills the FOV—we’re getting used to this by
now. There are yellow and reddish stars and a wishbone-shaped
obscuring feature with the point up on the east. I can never again
look at it with the 12” without disappointment.
NGC6210, the Blinking Planetary. The blinking effect was not observed
in the larger aperture, but everything else was. I kind of miss the
blinking effect.
M57 fills the FOV to about 2/3 with the 32mm eyepiece. The central
star was bright and steady with several other foreground stars
superimposed on the overall disk. For some reason the disk did not
show as much structure as seen in the 12” or Erick’s
22”. Maybe it was bright enough to mask the expected detail? Color
was not observed. The nebula was the usual blue-green of low
light-level perception.
I took a short snack break and when I returned to the observing
platform a globular was being viewed. I did not get its designation or
coordinates, but I did view it and it beautifully showed yellow and
reddish stars with prominent dark obscuring material.
A dark Barnard object in the neighborhood was searched for, but not
found. Wonder how Barnard found it?
Moving on to M16. While only a small part was in the FOV (where have
you heard that before?), that small part happened to be the Pillars of
Creation. Even with the 82”, the contrast was quite low and the
columns were not immediately discernable. Using averted vision they
were seen and once perceived, they were readily viewed and some detail
could be detected, even with direct vision. The view was like looking
at the Hubble picture, except for being colorless as the light level
was below the color threshold (mesoptic). Color or not, it was still
one of the highlights of this memorable night, and the only object I
stood in line twice for.
M20, the Trifid Nebula, was zeroed in and the intersecting dark lanes
were very prominent, more so than in most photographs, with a very
distinct three-dimensional look to them. It must be the scale! It was
most impressive.
By then it was about an hour before predawn light, and a cold wind
began to blow from the southwest. The dome channeled the draft
directly to the observing platform. Seeing went to heck, occasionally
the scope was buffeted by the wind, and my ears got cold. Until then
the seeing was almost perfect, or at least the best I have ever
experienced. Until a better night comes along (maybe in the next
hundred years or so), “perfect” will do just fine to describe
the night.
We shut the scope down, closed the observing slot and cleaned up donut
crumbs in the library conference room just as the eastern sky
brightened. We were bussed back to the visitor center just before
sunrise. Very tired, but a good tired, and aware that the 20 of us who
lasted all night were an historic group—we were the first!
Bill Wren said that he certainly considered the session to be a huge
success (no one was injured and no equipment was damaged) and the
observatory would try to have subsequent all night public observings,
particularly during the TSP next year. Get your money ready.
We later heard a somber bit of news. The 82” may be mothballed
sometime in the next 10 years. It's technologically obsolete and its
maintenance and operating cost can be better spent on the more modern
instruments. Parts of the 82” have already been abandoned, such as
the Coude spectrograph. So if anyone gets the opportunity to do
another all-nighter with the 82” (or any large aperture instrument),
GO FOR IT. Mortgage the farm, indenture the kids. It’s worth it.
Mike Brooks & Jim Anderson
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