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(IAAC) RE: Partial Listing of Asterisms and Some Comments



***********************************************
Some Random Thoughts and Examples of Asterisms
***********************************************
(Includes a Rough Listing of about 100 Asterisms)

The true definition of a constellation and an asterism have always been
tainted with some degree of ambiguity. Definitions range from;

"...a group of stars smaller than a constellation but larger than a star
cluster." 
Ian Ridpath; "Norton's Star Atlas" 18th Edition

to

"A prominent pattern of stars, usually with a popular name, that does
not constitute a complete constellation."
Jacqueline Mitton; "Dictionary to Astronomy." 

Asterisms could be classified into various types, as mentioned (as Lew
was suggesting) in some of the recent e-mails of the IAAC. I consider
that these can be divided into;

1) Classical Asterisms.

These groups were first classified as asterisms or subgroups of the
constellations, that are similar to a particular part of an object or
part of its anatomy. Ie; Orion's mid-centre - the so-called `Venus's
Mirror' or the Square of Pegasus. Other examples include; "The Pleiades"
and "The Hyades".  As I quoted in one of my e-mails each of you, about a
147 are commonly "recognised", as stated in 14th (and earlier editions)
of "Norton's Star Atlas" (Prior to 1968) . (Though no list are given
with this.) 

[I must give apologies to Brent about this. In my extensive astronomy
teaching, I have this listed in my footnotes, and it features in my
astronomical text given to my students. Unfortunately I don't have the
earlier this Edition any more, as all the pages fell out on one dewy
night in the mid 1970's, and I had to throw it out. Anyway, the version
I had was an early editions - one with the the astronomical index in the
front of the book. I looked in the 18th edition in my possession - and
you are correct - it isn't there!
I think it is written in the introduction on the first page of Chapter 5
"Stars" I'll will find it eventually though!!)  

The origins of asterisms came from adopted constellations of the past.
The recognised ones, mentioned in Norton's above, are likely referring
to the older constellations used before the IAU standardisation.
Originally these constellations had no boundaries, except as either the
`head' or `foot' of a particular group. It was not until 1925 that the
International Astronomical Union (IAU), the governing body for deciding
astronomical nomenclature and systems, specified the position of the
constellation boundaries. These adopted positions or subdivisions were
first established by Johann Bode for the epoch beginning on 1st January
1875. The southern section of the sky was adopted using recommendation
by Benjamin Gould about the same time. The basis for the work was
commissioned by the IAU who employed a French draughtsman named
Delaporte. (Article Attached as Endnote 1.) 
His selection for all current boundary positions of the constellations
have remained the same until now. However, precession of the equinox has
changed the stellar positions and the constellation boundaries. Looking
at a detailed star chart, the boundaries no longer align to specific
right ascensions and declinations. In some cases, including Pavo,
Triangulum Australe and the southern boundary of Dorado (that also
passes through the Large Magellanic Cloud.) the distortions are now
obvious. 
Eighty-eight constellations were selected from the most common groups
that were being used at the time. This official list was first adopted
by the IAU in 1922, and ratified in 1930. Of the ones from antiquity,
the constellation of Antinous is the only one deleted, and is now should
be considered an asterism. Others considered included the SMC and LMC as
constellations - Nubecula Major (NMa) and Nubecula Minor (NMi), however,
this was never formally accepted by the IAU, so they remain as
asterisms. After 1930's ratification, the majority of the common
asterisms were placed in the "ancient history" basket. 

Other constellations from other cultures are also classical asterisms,
including the Chinese and Korean constellations. (If we included these
in our listings, the number of "Classical" Asterisms would be in the
thousands!) 

A list of these types of asterisms follow;

********************************************************************************
*          General List of Known Asterisms : Version 1
********************************************************************************

1.) "Classical" Asterisms (as Old Discarded Constellations.)

All the following constellation were considered in the early meetings of
the IAU Commission. 

The first list is the constellations that remain but with their names
(thankfully) shortened.
Namely;
Antlia Pneumatica; Caelum Scalptorium; Columba Noae; Fornax Chemica;
Horologium Oscillatorium; Mensa or Mons Mensae; Phoenicoterus (now
Grus);
Musca or Musca Australis; Lynrsive Tigis (now Lynx); Norma et Regula;
Octans Hadleianus; Ophuichus vel Sepentarius; Pyxis or Pyxis Nautica;
Scutum Sobiescianum; Sextans Uraniae; Tubas Astronomics (now Telescopium
Solarium)
and Vulpecula et Ansere.

The second list should be considered "classical" asterisms.
These include;

Antinous
Argo Navis; Superconstellation of Carina, Puppis and Vela. (Pyxis?)
Cerberus
[Crux; (1229: -59:) Deleted as asterism and promoted to constellation;
Crux ex-Centaurus.]
Custos Messium
Felis
Globus Aerostaticus
Officina Topographica
Quadrans Muralis
Robur Carolinum (Alpha Robinis =Beta Car)
Machina Electria; 
Mons Maenalus
Musca Borealis
Nebecula Major
Nebecula Minor
Noctura
Turdus Solitarius
Sceptrum Brandenburgicum
Tarandus vel Rangifer
Triangulum Minor (or Triangula)

*****************************************************************************************

2.) Asterisms (Sub-Constellations)  
 
This third list are naked-eye or binocular asterisms that are parts of a
larger constellation or constellations. Most are visible to the
naked-eye, or are obvious in binoculars or a small telescope, and
subtend an angle of greater than about a degree. 

This list below is far from exhaustive;

Alpha Persei Cluster 
032419.0+495142;
Perseus; Mel 20 Cr39; Stars around Alpha Persei; d=184' 50 stars 

Andromeda Galaxy
04246+4116; Andromeda; M31/NGC 224; Andromeda Galaxy

Australian Eagle
-2630+0716; Delta, Omega, Sigma, Epsilon and Eta Canis Majoris 5Ox8O
(Aboriginal.)

The Bikini Bottom
Capricornus; Entire triangular outline of Capricornus (Sanford)

Circlet of Pisces
233111.5+034017; Pisces;
Southern Fish of Pisces; Gamma, 7, Kappa, Lambda, TX, Iota Theta Psc 5
degrees in diameter. 
(TX Piscium is a N-spectral class variable - ultra-red; Eastern Part of
the "Circlet.")

Coalsack/Black Magellanic Cloud
12 53:-53 00; Crux/Musca/Centaurus

Brocchi's Cluster
19256+2004; Collinder 399;1.4Ox1O	The Coathanger Vulpecula

Diamond Cross
10h 01m 34.9s -67d 21m 47s; Beta, Omega, Omicron and Upsilon Carinae

False Cross
08 58: -56 28:; Carina and Vela;  Kappa and Delta Velorum/ Iota and
Epsilon Carina

Flying Gripe/ Vultur Volans
19507+0852; Aqulia; Altair; Alpha, Beta Gamma Aquliae 	3 stars  5
degrees dia.

Hyades
0427:+1704:; Mel 25; Taurus; 3.0O

The Keystone
1650:+34:; Hercules; Eta, Pi, Epsilon and Zeta Herculis
 	
The Kids
0503+40: ; Auriga;  Epsilon, Eta and Zeta Aurigae Triangle of stars
south of Arcturus

Large Magellanic Cloud/ Nubecula Major/ LMC
1223:-6930; LMC;  4.7Ox4.1O

The Little Dipper
Ursa Minor

Medusa's Head
3h: 40O:; Perseus;  Stars Surrounding Beta, Omega, Rho, Pi,20,15,12
Persei.

Mercedes-Benz Symbol
Aquarius; "Y" shaped trefold containing the stars Zeta, Pi, Eta and
Gamma Aquarii, some 2Ox2O (Sanford)

Muscae Borealis/ Northern Fly
0245:+27:; Aries; Northern and central Aries; 35,39 and 41 Aretis
(2Ox2O)	

Northern Cross;
2020:+40:; Cygnus; 7Ox12O

Orion's Belt
0635:-02:; Orion; 4O ; 3 stars

Orion's Sword
0638:-0531: ; Orion; 2.5O ; 4to 8  stars

Velorum/ Omicron Velorum Cluster
08 40 18.0 -52 55 00; IC2391/ Cr191 Contains the central bright star
Omicron Velorum; 1.2 degrees
	
The Plough/ Charles's Wain/ Dipper
12 15:+5700:;  Ursa Major; 25O

The Pointers (South)
1422:-61: ; Centaurus; Alpha and Beta Centauri	6O

The Pointers (North)/The Keepers
1105:-59: ; Ursa Major;  Alpha and Beta Ursa Majoris; 7O

Scutum's Star Cloud
1841: -07: ; Scutum;  Bright Patch of the Milky Way (Refer Sky
Cat.2000.0) Near Alpha Sct

The Sickle
10h:+20:; Leo ; 12Ox8O

Square of Pegasus;
Pegasus		

Small Magellanic Cloud/ Nubecula Minor/ SMC
00 58 00.0 -72 46 00;  SMC/ NGC 292/ ESO29-21; Galaxy			

Summer Triangle
Deneb, Altair/ Vega

Southern Pleiades
10 72 57.0 -64 23 42;  IC2602/Mel 102/ Cr229;  Carina;  49' 60 stars; 
Mag 1.6; Surround 2nd mag. Theta Carinae

The Teapot
Sagittarius

The Throne
1230:-20: ; Corvus; Alpha, Epsilon, Beta, Gamma, Delta, Eta Corvi; 7Ox7O

Triangulum Galaxy
01 33 50.9 +30 39 37; M33/ NGC 598; Triangulum	

Pleiades/ The Seven Sisters
03 47 29.0 +24 06 18; M45; Taurus

Praesepe (Beehive)
084024.0+194000;
M44/ NGC 2632/ Cr 189; Cancer; 95'; 50 Stars

Venus' Mirror/ The Saucepan/ The Pot
0532: -02 25:; Orion; 4.5Ox4.5O

(Name ???)
1307:-02: ; Virgo; Delta, Gamma, Zeta,   Virginis 10Ox8O 

*******************************************************************************************

3) Telescopic Asterisms/ Mini- Asterisms

Amateur astronomy since the 1950's have added telescopic asterisms,
which are collections of stars, either visible in binoculars or in a
small telescope. Most of the recent ones added by amateurs tend to be
asterisms just below naked eye visibility. These asterisms are useful in
identifying fields of other truly deep-sky objects, and can make
interesting diversions during an observation sessions.

Mel 111/Cr256
12 25 06.0 +26 07 00; Mag 1.8; Gamma Coma Berenices; 275'min.arc.; 80
stars

IC 4665/ Mel 79/ Cr349
17 46 12.0 +05 43 00; Ophiuchus; 40' ; 30 stars

Northern Coalsack/ LDN 906
2040:+42;  Cygnus; Telescopic Nebula Hole

Kappa Crucis Cluster/ Jewel Box/ "A" Stars / NGC 4755 ??

Barnard 143;
19407+1057; Aquila; South of Lambda Aquilae. Diameter 2.5 degrees.) 

3a.) Additional "New" Asterisms. All Types:

The Little Queen (Phil Harrington's article appeared in the May 1998 S &
T. )
"W" of Cassiopeia; Cassiopeia

Dolphin's Diamonds (Phil Harrington's article appeared in the May 1998 S
& T. )
Delphinus

The Mini-Coathanger  (Discovered by Pennsylvanian Tom Whiting)

"Mini Orion" (William)
(17h 17'-24d 21m) Canis Major; Naked eye grouping.; 15'; 6 Stars; 

"Mini-Orion- Two" UC 0726-2305; (Luis)
RA (J2000.0):   07h 26m 59s Dec (J2000.0):  -23 5' 10" 
SAO 173752/ PPM 252419 and SAO 173752 Magnitude: 5.61

"The Tuft in the Tail of the Dog" (0724-3212) Collinder 140 (Steve Coe
and Linda Ross)

Golden Horseshoe/ ANR 1450-6612 or UC1450-6612
14 51 00.0 -66 12 00; 7.3v; 60'x48'; (A.James)

Golden Snake
14 49 00.0 -65 34 00; 12.0v; 18'; (A.James)

Delphinus Australis
09 07 06.0 -69 43 30; 9.8v; 15.'x10'; (A.James)

Eridanus Australis
Part of the River that aligns north-south from Eta Eridani down through
to Achernar. (A.James) Traditional

Eridanus Borealis
Part of the River that aligns east-west from Beta Eri/ Beta Ori to Eta
Eri (near Omicron Ceti (Mira)) (A.James) Traditional

M73 Aquarius Asterism (Found by Yann Potheir's)
(2055-1310); Aquarius
BTW, I have found another one near M73 (already an asterism) this
summer. I had located M73 and got prepared for drawing it and back at
the eyepiece, my unmotorized dob hadn't followed M73 and I had to move
back and by doing so I found a small clustering that looked very much
like M73. I started drawing it but moving back to M72, I got back to the
real M73.... Check for yourself.
46 Total 21/12/98
		
Listed Telescopic Asterisms.;  MegaStar 4.0
 
NGC7801  00 00 23.0  +50 44 24  ASTM   ---       ---              
---             BAS
NGC7826  00 05 15.0  -20 42 54  ASTM   ---       ---              
---             BAS
NGC7833  00 06 32.0  +27 38 30  ASTM   ---       ---              
---             BAS
NGC32  00 10 54.0  +18 47 00  ASTM   ---       ---              
---             NGC
NGC305  00 56 21.0  +12 03 48  ASTM   ---       ---              
---             RC3
NGC1146	02 57 38.0  +46 25 36  ASTM   ---       ---              
---             BAS
IC280  03 03 18.0  +42 21 00  ASTM   ---       ---              
---             NGC
NGC1523  04 06 12.0  -54 06 00  ASTM   ---       ---              
---             NGC
IC2091  04 46 36.0  -04 41 00  ASTM   ---       ---              
---             NGC
NGC1790  05 11 18.0  +52 04 00  ASTM   ---       ---               --- 
8-9 stars  RC3
NGC2054  05 45 12.0  -10 05 00  ASTM   ---       ---              
---             NGC
NGC2132  05 55 12.0  -59 55 00  ASTM   ---       ---              
---             RC3
NGC2220  06 21 48.0  -44 46 00  ASTM   ---       ---              
---             RC3
NGC2364  07 20 47.0  -07 33 00  ASTM   ---       ---              
---             BAS
NGC2408 07 40 30.0  +71 39 00  ASTM   ---       ---              
---             RC3
NGC2459  07 52 02.0  +09 33 24  ASTM   ---       ---              
---    5 stars  BAS
NGC2664  08 47 08.0  +12 36 18  ASTM   ---       ---              
---             BAS
NGC3036  09 49 16.0  -62 40 30  ASTM   ---       ---              
---             BAS
MAC1026-4339 10 26 01.7  -43 39 41  ASTM   ---       ---              
---             MAC
NGC3231  10 26 58.0  +66 48 54  ASTM   ---       ---               --- 
7 stars    BAS
NGC3520  11 05 30.0  -17 55 06  ASTM   ---       ---               --- 
4 stars    BAS
NGC4982  13 08 48.0  -10 35 00  ASTM   ---       ---              
---             NGC
NGC5043  13 16 40.0  -60 02 30  ASTM   ---       ---              
---             BAS
NGC5385  13 52 24.0  +76 11 00  ASTM   ---       ---               --- 
9 stars    RC3
NGC5571  14 19 36.0  +35 09 00  ASTM   ---       ---              
---             RC3
NGC6354  17 24 36.0  -38 32 00  ASTM   ---       ---              
---             NGC
NGC6430  17 44 36.0  +18 09 00  ASTM   ---       ---              
---             NGC
NGC6432  17 47 24.0  -24 53 00  ASTM   ---       ---               --- 
4 stars    RC3
NGC6724  18 57 00.0  +10 22 00  ASTM   ---       ---               --- 
4', 7*     RC3
NGC6728  18 57 24.0  -09 01 00  ASTM   ---       ---              
---             RC3
NGC6775  19 16 48.0  -00 55 00  ASTM   ---       ---              
---             RC3
NGC6832  19 48 06.0  +59 25 00  ASTM   ---       ---              
---             RC3
NGC6863  20 05 06.0  -03 34 00  ASTM   ---       ---               --- 
8 stars    RC3
NGC6874  20 07 48.0  +38 14 00  ASTM   ---       ---              
---             RC3
NGC6873  20 08 18.0  +21 06 00  ASTM   ---       ---              
---             RC3
NGC6896  20 18 00.0  +30 39 00  ASTM   ---       ---              
---             RC3
NGC6989  20 54 06.0  +45 17 00  ASTM   ---       ---               --- 
MW Region  RC3
NGC7005  21 02 00.0  -12 53 00  ASTM   ---       ---              
---             RC3
NGC7050  21 15 18.0  +36 12 00  ASTM   ---       ---              
---             RC3
NGC7055  21 19 24.0  +57 35 00  ASTM   ---       ---               --- 
10 stars   RC3
NGC7058  21 21 48.0  +50 48 00  ASTM   ---       ---              
---             RC3
NGC7134  21 48 54.0  -12 59 00  ASTM   ---       ---               --- 
5 stars    RC3
NGC7150  21 50 24.0  +49 45 00  ASTM   ---       ---              
---    5 stars  RC3
NGC7175  21 58 48.0  +54 49 00  ASTM   ---       ---               --- 
11 stars   RC3
NGC7234  22 12 06.0  +56 58 00  ASTM   ---       ---               --- 
8 stars    RC3
NGC7453  23 01 24.0  -06 21 00  ASTM   ---       ---              
---             RC3
NGC7526  23 13 54.0  -09 12 00  ASTM   ---       ---              
---             NGC 

******************************************************************************
Yann Potheir's Asterism List
(I have included these in my asterism listing above, and I hope Yann
doesn't mind.)

ANR 0125+58; 01h25.0, N5800'; D=30'; ; MA=20cm; C=x
ANR 0509+47; 05h09.6, N4702'; D=3.0'   ; 15 stars mag.12-14; MA=20cm;
C=x
ANR 0604+03; 06h04.8, N0351'; D=3.5'; 12 stars mag13.5; MA=45cm; C=x
ANR 0637+24; 06h37.0, N2408'; D=5'x2'; 12 stars mag.10-12; MA=20cm; C=x
ANR 0640+06; 06h40.0, N0600'; D=12'; 15 stars; with Cr 106; MA=11cm
ANR 1818-12; 18h18.0, S1202'; D=14'x4'; MA=20cm; C=x
ANR 1932+10; 19h32.0, N1042'; D=1.0'x0.5'; 6 stars mag.12-13; MA=15cm;
C=xx
ANR 1934+10; 19h34.7, N1053'; D=1.7'; 12 stars mag.13-15; MA=45cm; C=xx
ANR 1936+18; 19h36.0, N1830'; D=10'; 12 stars mag.10-12; MA=binoculars;
C=x
ANR 1947+18; 19h47.5, N1850'; D=5.0'; 15 stars mag.11-13; MA=20cm;
C=xxx
ANR 2011+37; 20h11.0, N3700'; ; 10-15 stars; 11cm
ANR 2012+36; 20h12.0, N3600'; ; 10-15 stars mag8 and fainter; MA=11cm;
C=x
ANR 2020-12; 20h20.0, S1220'; D=0.8'; 4 stars mag.15-16; MA=45cm; C=x
ANR 2043+47; 20h43.5, N4757'; D=8'; 8 stars mag.10-12; MA=binoculars;
C=x
ANR 2124+49; 21h24.0, N4900'; ; 10-12 stars; with NGC 7067; MA=11cm
ANR 2139+65; 21h39.3, N6549'; D=8'x5'; 10 stars mag.11-13; MA=20cm; C=x
ANR 2143+51; 21h43.6, N5104'; D=4.0'; 20 stars mag.11-13; MA=20cm; C=x

Comments:
ANR means "amas non repertories" ie "uncatalogued clusters".
The number following ANR is a composite of both coordinates.
RA and DEC are to be found next.
D is the diameter/size of the object in arc minutes. MA is the minimum
aperture the asterism was seen (not always the real minimum, you have to
rely on the magnitude estimates of the stars).
C is the confirmation of other observers; no C means the asterism has
not
been confirmed and "C=x" means the object has been seen by another
observer.

If you happen to cross one of these asterisms, do not hesitate to
contact me. More confirmations are always welcome.

**********************************************************************

In regards classification of "ANR" Asterisms, Yann Pothier's is a good
one. 

It is clear, and give a good estimation of size, brightness and aperture
required to see it. One comment, that might be useful, is that a short
description of the shape and a possible name would be useful. The
abbreviation "ASTM" or "ASM" might be better, and perhaps a bit more
Universal. (ATM would have an unfortunate connotation!!)

General Comments

As amateurs we seldom get any opportunity of using our "tempered"
imaginations and apply them to the skies, but perhaps I spent too many
idle hours in my youth searching for patterns in the clouds! (Note:
Anyone applying their imaginations to established deep-sky objects
should be shot on sight! One should never apply imaginations to what
they see - else we created illusions that are worthless to our fellow
amateurs.) Although I have never really looked for deliberately for
asterisms, I have certainly came across a few of them over the years,
and most I never wrote down! I could just kick myself now!

I have given the following list to you, and any further comments would
be appreciated, and welcomed. I am prepared to maintain a listing - as
long as I don't tread ant any toes, and additions could easily be
circulated, if required. I think the aim is to get a suitable listing,
so that an organised "search-and-kill mission" could be undertaken -
naturally for observations into the IAAC Log !!!

Any suggestions??? 

**************************************************************************

Regards,
Andrew James


Endnote:
As a Planetary Nebulae fanatic, I have made a few searches around quite
a few southern planetaries, and found some interesting objects
(including "The Golden Horseshoe."). An extact of this is included
below;

Southern Asterisms: The Golden Horseshoe.

Centred on 14h51.0' -66O 12' is  another brighter asterism that my
friend's 14-years old daughter Alexandra Popovic coins 'The Golden
Horseshoe.' It lies between Alpha ( ) Circini and Gamma ( ) Triangulum
Australis, and some two-thirds the bisected distance in a straight line
between these stars. To the naked eye the brightest star in the asterism
is the 6.2 magnitude bluish Zeta ( ) Circini (SAO252951). The Golden
Horseshoe has a diameter c.0.8 degrees and contains some 25 stars -
three of 6th magnitude, six are 7th, eleven of 8th and five of 9th. It
also contains a number of double stars.
In the finder, this asterism is obvious, though the larger telescopes
may have serious trouble in getting the object within the telescopic
field. A small telescope, say 7.5cm. or 10cm. using low power will have
no trouble placing it into one field.
Another 'mini-asterism' lies in the northern part of the 'horseshoe',
which I call the 'Golden Snake'. This is an 'S' shaped line of stars
that extends NNE from the 7.6 magnitude star SAO252951 (GSC9019:467) by
some 12'min.arc. in length towards Alpha Circini. Twisted like a snake,
the line of twelve 11th and 12th magnitude stars end in a 'forked
tongue'. A 7.5cm. should see these easily in dark skies, a 10cm. if you
are in a sky-lit suburb. 
Bottom star of the straight line of five stars in the SE of the field of
the horseshoe is the Innes triple I 369 (14487-6635). Magnitudes of the
wide AB pair are 5.90 and 9.0, separated by 30.0"sec.arc. at PA 80
degrees., so this dainty white pair is easily visible in a 7.5cm. Closer
inspection reveals that the B star is again double. At magnitudes 9.0
and 11.0, the BC components are separated by 2.7"sec.arc. at PA 224.1
degrees. Using medium powers, a 10.5cm. telescope easily splits these
stars. For some reason Burnham's does not have it placed in his list of
doubles within Circinus. Worst there seems a difference in the reference
material in regards the AB separation. Of the four sources, Sky
Catalogue 2000.0 lists it as 60.0"sec.arc, while others list it as 46",
30" and 6.0"sec.arc., respectfully. All my data quoted above is taken
from the Washington Double Star Catalogue; 1996 (WDS96). Visually,
30"sec.arc. is closer to the truth. Checking the observational data,
Geoffrey Douglass of the US Navel Observatory confirmed this is correct.
The spectral types of the AB system are B2.5Ve and B7/8V. All proper
motions are also similar, suggesting that the three stars are really
associated. However, little has changed in the positions since Innes
observations in 1902.
On the opposite end of the horseshoe is the John Herschel pair HJ 4707
(145420-662437) This nearly equal yellow and white pair, has quoted
magnitudes of 7.5 and 7.9. Since the first observation in 1837 the
separation had slowly decreased, until sometime is the early 1960's. Ie.
1.5"sec.arc to a minimum of 0.54"sec.arc. Since then the separation has
began to increase and according to the calculated ephemerides of the 4th
Catalogue of Visual Binaries, the current separation is 0.84"sec.arc. at
PA 294 degrees. Then if this is correct, an aperture of 20cm. could just
resolve the pair under good seeing conditions and medium-high
magnification. Visually, I can just see it in a 30cm., suggesting a
separation of ~0.65-0.7 sec.arc. and the position angle may also be out
by +10 degrees or so. It is possible that the binary star ephemeris is
incorrect. (Any comments???) To my eyes, the pair appears strongly
yellow in colour. It is no doubt, from the 41 measures made to date, it
is likely a long period binary. In 1948 Woolley and Mason calculated the
retrograde orbit has a period of 288 years. Another known problem is the
observed magnitude difference ( m). Herschel's observations state a
difference of 0.4 - and this figure is given in the IDS. The most recent
observations suggest no difference at all - magnitude 7.00 and 7.00,
respectfully. My own observation suggests that the difference is nearer
Herschel's. Could this be a suspected variable?

NOTE: I don't know if I am allowed to give actual plugs in this forum -
but some of my observations (including asterisms) appear on Doug
Snyder's 'Planetary Nebulae Homepage', that include my "Neat Southern
Planetaries" Series, that Doug has graciously placed within his page. 
His URL is;
http://blackskies.com.au

If you haven't seen it, I think you would find the images and the page
layout and observational information just fabulous - even if you wished
to avoid my (long winded) planetary series like the plague!!!

In the new year I will be placing another five or six parts in the next
month or so.
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