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Science Forum Index » Astro - Amateur Forum » SAA: Predawn Messier session (15X70 binoculars)
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| Margo Schulter |
 Posted: Tue Apr 15, 2008 11:39 pm |
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Hello, everyone, and what a pleasure to share a report on a great
observing session this morning before dawn, maybe a "Messier 5K,"
since it lasted for something not too far from 1/8 the duration
of a Messier Marathon.
An important conclusion I draw from this pleasant excursion
through Scorpius and Sagittarius is that 15X70 binoculars have a
special niche for _urban_ deek sky viewing, where the extra
aperture and magnification can help overcome light pollution.
Getting up at around 0410 PDT, just around the time of moonset, I
got out my binoculars, a couple of relevant atlas charts, and
my log book for notes and sketches, along with a red LED
flashlight. Rather than dealing with the complications of an
L-adapter and monopod, I would simply recline on my bed and
handhold the binoculars, hopefully for the most part with a bit
of bracing.
Quickly I spotted the asterism familiar to me as the "Mirrored
Radical Sign" in Ophiuchus at an RA of around 17h15m to 17h30m
and a declination of -25-o. The four main stars look rather like
a square root sign with left-right mirroring, with the following
crude ASCII diagram showing the Flamsteed numbers and Bayer
letters of these stars in Ophiuchus:
51 44 omicron
* * *
*
theta
This is a signal for anticipation and excitement, as I learned
late last spring with 7X50 binoculars, since when it appears then
M7 is not far behind.
Indeed I followed a sequence of stars, still rather familiar from
last year, down and then up to M7 -- beautifully clear and
resolved, a kind of fireworks burst of fine stars, despite the
light pollution and near-horizon murk.
Appreciating this wide-field view of Ptolemy's cluster, I found
it easy to locate M6, the Butterfly cluster, as well. These clear
and resolved views made me reflect on Galileo's delight at
resolving the Milky Way into stars, or discovering that a cluster
like the Pleiades (M45) had many more stars than hitherto known
or expected.
Last year, with the 7X50 binoculars and aging eyes with a likely
maximum dilation of 5-6mm (as estimated at my last eye exam) apt
to decrease the effective aperture considerably, I could
recognize M7 as a subtle "patch" which a bit of observation
showed to be an astronomical rather than meteorological
phenomenon, and which more intent examination made it possible to
resolve somewhat into stars. The tentative and yet ultimately
confident identification of my first Messier object deliberately
observed as such had its own special charm.
With the 15X70 binoculars, in contrast, I was interested in using
averted vision to see yet more detail in the delightfully
resolved cluster -- an exquisite swarm of finely textured stars
-- rather than simply to confirm that I was indeed viewing the
sought object.
Soon I spotted M8 and M20, and by around 0500, also my beloved
M24. the Small Sagittarius Star Cloud, a portion of the galaxy at
a distance of about 10,000-16,000 light years toward the center,
in a region where the prevailing and obscuring interstellar dust
is thinner. Then followed M25, a kind of miniature version of the
view that I grew last summer to know and love in my 20cm f/6 Dob.
The pattern of three bright stars, now _above_ this open cluster
since the binoculars were giving a "correct view," helped to
confirm the identification.
Finally, as twilight was growing brighter, I spotted a circular
smudge that seemed to be M22. The asterisms looked generally
right, and I'd like to confirm this in coming weeks when there's
a bit more margin between the appearance of this region of
Sagittarius in my viewing window and the coming of sunrise.
Having become familiar with the celestial "playground," as Marty
has well called it, around Sagittarius, with 7X50 binoculars and
Dob, I found that my first encounter with 15X70 binoculars
highlighted the charms of this rather classic "Richest-Field
Telescope," or RFT.
FIrst, the clarity of resolution is wonderful, and combines with
the 4-o 18' field of view, so that starhopping has a feel and
freedom of the kind one associates with binoculars, in contrast
to the more gradual and disciplined approach required with the
Dob, even when equipped with an ultrawide eyepiece with a field
of just over 2-o. Swinging up from M8 and M20, through a pleasant
asterism with a mild "zigzag" pattern (14, Mu, 15, 16 Sagittarii)
to M24, and sweeping from there to M25, is smooth and intuitive.
The Dob, of course, at 40X with a 30mm ultrawide 2" eyepiece,
would show much more detail; and the 7X50 binoculars give more of
a sense of constellations _as constellations_. Each viewpoint has
its own attractions.
For observing objects like M6 and M7 which have a declination
more southerly than -30-o or so, the 15X70 binoculars have the
simple advantage that I can view this region with them, while the
Dob would encounter the obstacle of the room's wall. With the
binoculars, I was able to view two stars in Scorpius below M7
later identified as a tad lower than -40-o (t1/t2 Scorpii).
Of course, with either pair of binoculars or the Dob, I would see
far more in darker skies. However, I find it fascinating than urban
deep sky observing can be an especially attractive "niche" for
the 15X70's.
Most appreciatively,
Margo Schulter
mschulter@calweb.com |
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| Marty |
| Posted: Thu Apr 17, 2008 9:39 pm |
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Neat report Margo! It's been awhile since I've been out, aside from
constellation gazing... it's been a long winter, and tonight it's
raining. Your post makes me feel my shortage of starlight. One a these
nights...
Marty |
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| Margo Schulter |
| Posted: Fri Apr 18, 2008 1:27 am |
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Marty <movac5@webtv.net> wrote:
Quote: Neat report Margo! It's been awhile since I've been out, aside from
constellation gazing... it's been a long winter, and tonight it's
raining. Your post makes me feel my shortage of starlight. One a these
nights...
Marty
Hi, Marty!
My regrets for your uncooperative weather, at least from an astronomical
point of view: I remember that "corncam" photograph, and wonder if it will
be agriculturally beneficial, at least.
Anyway, a humorous correction: somehow I misread a notation in the
_Millennium Star Atlas_ for two stars in Scorpius as "t1/t2"
(with lowercase "t," maybe some unfamiliar catalogue?) when it
was actually the Greek iota: that is, transliterated approximately
"i1/i2" or "Iota1/Iota2."
This morning I had some more excitement: seeing and later identifying
NGC 6231 in Scorpius, the "Little Jewel Box" as I understand that it
is sometimes called, an open cluster at around 1990 parsecs or 6500
light years according to one recent estimate. This is located at
RA 16h54m, Dec -41d49m, or about 10-o above the local horizon.
Then I followed with some usual Messier objects, and as twilight
advanced had a chance to confirm fairly confidently that what
I saw in my previous session was indeed M22.
It's curious to speak of using a pair of binoculars with "situational
setting circles," but that's pretty much what it feels like. If I
know the local sidereal time (LST), and roughly how my observing
window from a given vantage point maps to a range of hour angles
and declinations, then I can have a good idea of my general
whereabouts in the sky, and take the starhopping from there.
What I do realize is that in this kind of in-house environment,
I tend to navigate by mostly binocular asterisms (or finder
asterisms with the Dob) rather than by constellations, or at
least as much. Of course, I can and do recognize with naked
eye viewing such landmarks as Canis Major, the sword and belt
of Orion (right near the upper limits of my window for binocular
viewing, with a bit of gymnastics -- what fun if I could get the
Dob to an obstructed view that close to the celestial equator),
Scorpio, and the teapot of Sagittarius.
However, a lot of navigating is either by guesstimates of RA/Dec,
or by asterisms. It's curious that I've been using the "Mirrored
Radical Sign" in Ophiuchi as a landmark on the road from Antares
to M7 for almost a year -- but only in writing my previous post
that I learned it's actually in Ophiuchi! I would have guessed
Scorpius, maybe because both Antares and M7 are in it.
This morning I got the idea of trying to extend my southern
limit by raising myself a bit higher when sitting on my bed.
A large pillow looked about right -- and indeed moved my
lower limit from around -41-o to something like -44-o or so.
I had earlier drawn up an observing list of objects down to
around -41-o -- but hadn't taken note of NGC 6231, because it
was just below this cutoff.
So I got on my seat, swept the lowest area in the window, and
found a nice "rather prominent fuzzy" that at I first assumed
might be some open cluster on my list. Then, later in the day,
I found out that it was NGC 6231 -- and here a sketch with
notes about approximate distances of nearby stars in viewing
fields helped make a confident identification.
A fascinating thing I realized when looking at the charts
was how you can have open clusters within open clusters. Thus
the fchart map that most definitively confirmed my
identification based on some atlas charts suggests that I
could also claim credit for Cr 316, within which NGC 6231
resides -- but maybe I should do that after having a further
look and seeking an appreciation for the structure of this
larger object.
There's more to say -- but I'll save that for a further
post, since my main purpose is to thank you for your
friendly note and, of course, wish you the best observing
once things clear up.
With many thanks,
Margo
mschulter@calweb.com |
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| oriel36 |
| Posted: Fri Apr 18, 2008 8:13 am |
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Guest
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On Apr 18, 8:27 am, Margo Schulter <mschul...@web1.calweb.com> wrote:
Quote: Marty <mov...@webtv.net> wrote:
Neat report Margo! It's been awhile since I've been out, aside from
constellation gazing... it's been a long winter, and tonight it's
raining. Your post makes me feel my shortage of starlight. One a these
nights...
Marty
Hi, Marty!
My regrets for your uncooperative weather, at least from an astronomical
point of view: I remember that "corncam" photograph, and wonder if it will
be agriculturally beneficial, at least.
Anyway, a humorous correction: somehow I misread a notation in the
_Millennium Star Atlas_ for two stars in Scorpius as "t1/t2"
(with lowercase "t," maybe some unfamiliar catalogue?) when it
was actually the Greek iota: that is, transliterated approximately
"i1/i2" or "Iota1/Iota2."
This morning I had some more excitement: seeing and later identifying
NGC 6231 in Scorpius, the "Little Jewel Box" as I understand that it
is sometimes called, an open cluster at around 1990 parsecs or 6500
light years according to one recent estimate. This is located at
RA 16h54m, Dec -41d49m, or about 10-o above the local horizon.
Then I followed with some usual Messier objects, and as twilight
advanced had a chance to confirm fairly confidently that what
I saw in my previous session was indeed M22.
It's curious to speak of using a pair of binoculars with "situational
setting circles," but that's pretty much what it feels like. If I
know the local sidereal time (LST), and roughly how my observing
window from a given vantage point maps to a range of hour angles
and declinations, then I can have a good idea of my general
whereabouts in the sky, and take the starhopping from there.
What I do realize is that in this kind of in-house environment,
I tend to navigate by mostly binocular asterisms (or finder
asterisms with the Dob) rather than by constellations, or at
least as much. Of course, I can and do recognize with naked
eye viewing such landmarks as Canis Major, the sword and belt
of Orion (right near the upper limits of my window for binocular
viewing, with a bit of gymnastics -- what fun if I could get the
Dob to an obstructed view that close to the celestial equator),
Scorpio, and the teapot of Sagittarius.
However, a lot of navigating is either by guesstimates of RA/Dec,
or by asterisms. It's curious that I've been using the "Mirrored
Radical Sign" in Ophiuchi as a landmark on the road from Antares
to M7 for almost a year -- but only in writing my previous post
that I learned it's actually in Ophiuchi! I would have guessed
Scorpius, maybe because both Antares and M7 are in it.
This morning I got the idea of trying to extend my southern
limit by raising myself a bit higher when sitting on my bed.
A large pillow looked about right -- and indeed moved my
lower limit from around -41-o to something like -44-o or so.
I had earlier drawn up an observing list of objects down to
around -41-o -- but hadn't taken note of NGC 6231, because it
was just below this cutoff.
So I got on my seat, swept the lowest area in the window, and
found a nice "rather prominent fuzzy" that at I first assumed
might be some open cluster on my list. Then, later in the day,
I found out that it was NGC 6231 -- and here a sketch with
notes about approximate distances of nearby stars in viewing
fields helped make a confident identification.
A fascinating thing I realized when looking at the charts
was how you can have open clusters within open clusters. Thus
the fchart map that most definitively confirmed my
identification based on some atlas charts suggests that I
could also claim credit for Cr 316, within which NGC 6231
resides -- but maybe I should do that after having a further
look and seeking an appreciation for the structure of this
larger object.
There's more to say -- but I'll save that for a further
post, since my main purpose is to thank you for your
friendly note and, of course, wish you the best observing
once things clear up.
With many thanks,
Margo
mschul...@calweb.com
I recall that you mentioned Nicolas of Cusa in your posts and this is
a man you should listen to.He wrote at a time just before the
technical arguments for heliocentric reasoning started to emerge with
Copernicus and while his main arguments for a motive Earth are based
on theological rather than technical considerations,he does ,in
fact,get it right.
He is basically arguing against the very constellational geometry that
fills you posts,to borrow his argument -
To borrow the argument -
Suppose person A were on the earth somewhere below the north pole of
the heavens and person B were at the north pole of the heavens. In
that case, to A the pole would appear to be at the zenith, and A would
believe himself to be at the center; to B the earth would appear to be
at the zenith, and B would believe himself to be at the center. Thus,
A's zenith would be B's center, and B's zenith would be A's Hence Cusa
could write in the early 15th century -
"And wherever anyone would be, he would believe himself to be at the
center.Therefore, merge these different imaginative pictures so that
the center is the zenith and vice versa. Thereupon you will see--
through the intellect, to which only learned ignorance is of help--
that the world and its motion and shape cannot be apprehended. For
[the world] will appear as a wheel in a wheel and a sphere in a
sphere-- having its center and circumference nowhere. . . " Nicolas of
Cusa
When Sam Wormsley shows up here with the ridiculous mainstream view
of 'every point is the valid center of the Universe' type thing he is
heading in the opposite direction to Cusa,where Cusa is heading in the
direction of heliocentricity,the empiricist runs along the route to
sub-geocentric astrology.
Now you are Marty are good people,I have no doubt about
that,however,what you call astronomy is simply an observational/
magnification exercise designed around a celestial sphere
convenience,the Earth may as well be flat and non-rotating for the
purpose which you enjoy so much.I am all in favor of imaging but the
raw data then goes into creating empirical junk which is then dumped
into the celestial arenaon account of the astrological framework. Want
to see warped space ?,is this warped enough for you ? -
http://www.opencourse.info/astronomy/introduction/02.motion_stars_sun/celestial_sphere_anim.gif
The central theme of observational astrology is to forget that the
Earth is moving at all and throw every bit of imaginative junk into
the celestial arena to match the sub-geocentric standard of reasoning
which creates the celestial sphere in the first place. |
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| Marty |
| Posted: Sat Apr 19, 2008 8:12 am |
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Hi Margo,
Always fun to hear of your explorations of your window universe!
(And to see an observing report on SAA... Hopefully, Spring will bring a
little more "amateur astronomical" activity to the group...) You're
dealing with what most would consider an abysmal astronomical situation
very well! I wonder if to some extent your room acts as an inhabitable
dewcap...? 
You mention your mixup with the Greek alphabet... I have to
confess when I post something in here, once I get past the "named"
stars, I have to pull out Norton's Star Atlas just to read the names of
the Greek characters so that I can spell 'em out in my post. Heck, it
took ME a while to memorize THIS alphabet.
You're also observing at a time of day when I'm generally
unconscious... I can stay UP til then with no problems, but getting up
then requires electrodes to start my heart. When I was a kid, I
associated the rising of Sirius with the coming beginning of the school
year, which sort of shows what time I was out walking around in the
Summer. (Well, actually, it was the lower end of a long curving tail,
hanging down from a kite formed by the belt and sword of Orion...)
Marty |
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| Margo Schulter |
| Posted: Sun Apr 20, 2008 2:53 pm |
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Marty <movac5@webtv.net> wrote:
Quote: Hi Margo,
Always fun to hear of your explorations of your window universe!
(And to see an observing report on SAA... Hopefully, Spring will bring a
little more "amateur astronomical" activity to the group...) You're
dealing with what most would consider an abysmal astronomical situation
very well! I wonder if to some extent your room acts as an inhabitable
dewcap...?
Hi, Marty. That "inhabitable dewcap" is a gem, and I may quote you on
that, with your permission (you deserve full credit).
Last night I had a strange experience with viewing the Moon, and I'm
curious as to what might have happened, although some information I've
seen assures me that no real harm was done. Using my 15X70 binoculars
and trying to find a DSO where the full moon was, not unpredictably,
interfering with even this rather bright object, I decided to have a
look at the Moon itself. When viewing the February 20 eclipse from
an outdoor location, and then enjoying the usual full Moon after
this event, I had no problems.
Anyway, for some reason, when I looked at the Moon with my naked eyes
to get them a bit light-adapted and then tried the binoculars, the
Moon looked _very_ bright, indeed uncomfortably so. I seem to recall
that the aperture at which a neutral density or variable polarizing
filter is recommended is about 4" or 100mm or so.
After a few very uncomfortable attempts to view our natural satellite
for a few seconds or so each, I wisely abandoned the attempt, and tried
my Dob with a variable polarizing filter, which was fine. I noticed
that my right eye seemed a bit teary -- not from the viewing in the
Dob with the filter, which was at a comfortable light level, but
evidently still from the earlier binocular viewing. Even now, about
12 hours later, my eye sometimes feels a bit strained -- as it once
was from an early telescope session last summer which taught me
definitely to use a shroud for protection from local glare (at
first a towel, and then an Orion Lights Out Observing Canopy).
I've seen threads and discussions about how viewing the Moon through
even a large telescope (without filter) shouldn't do any permanent
eye damage -- _quite unlike the situation with the Sun_ -- so I guess
that it's a question of bearing with this and letting my eyes get
fully back to normal. I wonder if somehow the window glass might have
increased the lunar glare effect, since I didn't have any problem like
this in my post-eclipse viewing in February.
Quote: You mention your mixup with the Greek alphabet... I have to
confess when I post something in here, once I get past the "named"
stars, I have to pull out Norton's Star Atlas just to read the names of
the Greek characters so that I can spell 'em out in my post. Heck, it
took ME a while to memorize THIS alphabet.
Yes, sometimes I need to check which character is which, also.
Quote: You're also observing at a time of day when I'm generally
unconscious... I can stay UP til then with no problems, but getting up
then requires electrodes to start my heart. When I was a kid, I
associated the rising of Sirius with the coming beginning of the school
year, which sort of shows what time I was out walking around in the
Summer. (Well, actually, it was the lower end of a long curving tail,
hanging down from a kite formed by the belt and sword of Orion...)
Often I've leaned in your direction, also: at around the beginning of
last summer, I was looking at Fomalhaut. Of course, from my apartment,
I can only see things within a couple of hours of right ascension of
the meridian, which makes the calendar seem a bit different. However,
I may be getting more active in some local star parties, which would
give me another perspective. Astronomy seems fun as either an outdoor
or indoor sport.
With many thanks,
Margo |
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