Zone 71, Master Map
Bootes
ζ
M101
Alcor
Mizar
+52°00'
c
e
κ2
κ1
+50°00'
ι
+54°00'
Normal View
Zone Master, Normal View, 10 deg FOV
Alkaid
+48°00'
η
Ursa Major
f
λ
14h 12m
14h 00m
13h 48m
Whirlpool Galaxy
M51
13h 36m
13h 24m
d
+46°00'
Canes Venatici
13h 12m
13h 00m
12h 48m
Zone 71, Map 1
Normal Image
ζ
Zeta UMa
Mizar
Bemporad 6
h2649
+53°00'
STF 1695
+54°00'
Alcor
+55°00'
Sky charts generated by TheSky Software; used by permission of Software Bisque Inc.
+52°00'
Espin 733
Canes Venatici
+51°00'
NGC 5225
STF 1718
STF 1770
+50°00'
OS 263
Bemporad 4
A. G. 190
13h 36m
13h 30m
13h 24m
13h 18m
13h 12m
13h 06m
13h 00m
12h 54m
Zone 71, Map 1
Mirror Image
+55°00'
Sky charts generated by TheSky Software; used by permission of Software Bisque Inc.
Alcor
Zeta UMaζ
Bemporad 6
h2649
Espin 733
Canes Venatici
+52°00'
+53°00'
STF 1695
+54°00'
Mizar
Espin 730
+51°00'
NGC 5225
STF 1718
+50°00'
OS 263
Bemporad 4
A. G. 190
12h 54m
13h 00m
13h 06m
13h 12m
13h 18m
13h 24m
13h 30m
13h 36m
Zone 71, Map 2
Normal Image
+50°00'
Sky charts generated by TheSky Software; used by permission of Software Bisque Inc.
Bemporad 4
STF 1758
+49°00'
A. G. 190
h2642
+48°00'
h2667
Espin 608
STF 1747
h2634
h2627
NGC 5194
+47°00'
NGC 5195
Whirlpool Galaxy
M51
NGC 5173
NGC 4800
+46°00'
Espin 2646
NGC 5198
+45°00'
OS 257
Kazeza 58
13h 36m
13h 30m
13h 24m
13h 18m
13h 12m
13h 06m
13h 00m
12h 54m
Zone 71, Map 2
Mirror Image
+50°00'
Sky charts generated by TheSky Software; used by permission of Software Bisque Inc.
Bemporad 4
+49°00'
A. G. 190
STF 1758
+48°00'
h2642
STF 1747
h2634
NGC 5195
M51 Whirlpool Galaxy
NGC 5194
+47°00'
h2627
Espin 2646
NGC 5198
NGC 5173
+46°00'
NGC 4800
+45°00'
OS 257
Kazeza 58
12h 54m
13h 00m
13h 06m
13h 12m
13h 18m
13h 24m
13h 30m
13h 36m
Zone 71, Map 3
Normal Image
NGC 5486
NGC 5485
Zeta UMa
Mizar
Alcor
NGC 5473
+55°00'
Sky charts generated by TheSky Software; used by permission of Software Bisque Inc.
M101
NGC 5457
+54°00'
ζ
Bootes
Bemporad 6
h2694
+53°00'
NGC 5474
+52°00'
STF 1795
Canes Venatici
+51°00'
NGC 5225
NGC 5480
+50°00'
STF 1770
STF 1774 rej
h2676
H VI 112
14h 06m
A. G. 190
14h 00m
13h 54m
13h 48m
13h 42m
13h 36m
13h 30m
13h 24m
Zone 71, Map 3
Mirror Image
NGC 5486
NGC 5485
NGC 5473
Alcor
Mizar
Bootes
h2649
M101
NGC 5457
Bemporad 6
h2694
+54°00'
Zeta UMaζ
+55°00'
Sky charts generated by TheSky Software; used by permission of Software Bisque Inc.
NGC 5474
+53°00'
Espin 733
+52°00'
STF 1795
Canes Venatici
+51°00'
NGC 5225
NGC 5480
+50°00'
STF 1770
STF 1774 rej
h2676
A. G. 190
13h 24m
13h 30m
13h 36m
13h 42m
13h 48m
13h 54m
14h 00m
14h 06m
Zone 71, Map 4
Normal Image
+50°00'
Sky charts generated by TheSky Software; used by permission of Software Bisque Inc.
STF 1774 rej
h2676
η
Eta UMa
NGC 5448
+49°00'
A. G. 190
H VI 112
13 Boo
Alkaid
STF 1758
LDS 5800
Ursa Major
Bur 802
+48°00'
STF 1806
h2667
Espin 608
NGC 5195
NGC 5377
NGC 5194
Espin 2646
NGC 5198
Whirlpool Galaxy
M51
NGC 5173
+46°00'
h2697
Swift 1
STF 1776
14h 00m
13h 54m
13h 48m
+45°00'
h2680
14h 06m
+47°00'
STF 1747
Canes Venatici
13h 42m
13h 36m
13h 30m
13h 24m
Zone 71, Map 4
Mirror Image
+50°00'
Sky charts generated by TheSky Software; used by permission of Software Bisque Inc.
STF 1774 rej
h2676
η
STF 1758
Eta UMa
Alkaid
NGC 5448
+49°00'
A. G. 190
Ursa Maj
Bur 802
h2667
Espin 608
STF 1747
+48°00'
LDS 5800
NGC 5195
M51
NGC 5194 Whirlpool Galaxy
+47°00'
Canes V
NGC 5377
NGC 5198 Espin 2646
NGC 5173
+46°00'
h2697
Swift 1
STF 1776
+45°00'
h2680
Kazeza 58
13h 24m
13h 30m
13h 36m
13h 42m
13h 48m
13h 54m
14h 00m
14h 06m
Zone 71
Index
1 Reference Star, 21 Double Stars, 6 Galaxies
A
N
A. G. 190 ............................................. 15
Bemporad 4............................................ 8
Bemporad 6............................................ 9
Bur 802 ................................................ 16
NGC 5173 ............................................ 20
NGC 5194 ............................................ 17
NGC 5195 ............................................ 19
NGC 5198 ............................................ 20
NGC 5225 ............................................ 12
NGC 5377 ............................................ 19
E
O
Espin 2646 ........................................... 16
Espin 733 ............................................... 5
Eta UMa............................................... 13
OS 263 ................................................... 6
H
h2634 ..................................................... 7
h2642 ..................................................... 8
h2649 ..................................................... 4
h2680 ................................................... 14
h2694 ................................................... 10
STF 1718................................................ 5
STF 1747................................................ 7
STF 1758.............................................. 15
STF 1770.............................................. 11
STF 1774 rej .......................................... 9
STF 1776.............................................. 13
STF 1795.............................................. 10
L
Z
LDS 5800............................................. 14
Zeta UMa ............................................... 2
B
S
-1-
Zone 71
Zone 71, Map 1
Double Stars
Easy
Zeta UMa
Rating: 2 E
79 UMa; Mizar; STF 1744ADS 8891; HD 116656; SAO 28737
Astronomical League Program: Double Star Club
Position: 1324+5456
A
B
Magnitude
2.23
3.85
Separation PA
—
—
14.4 153 +
Year
—
1998
Spectra
A2 V
A2 V
Colors
W
W
Notes:
Zeta was found to be a telescopic binary by Riccioli in 1650 and re-discovered by G.
Kirch on September 7, 1700. It was first measured by Bradley in 1755. It was also the
first binary photographed (in 1857 by G. P. Bond, Harvard Observatory). And, it is the
first spectroscopic binary discovered (both stars A and B, by Pickering, 1889). Pease was
the first astronomer to optically resolve this spectroscopic binary with the 20-foot
interferometer at Mt. Wilson (1925).
The Aa orbit only takes 20.5386 days. The Bb orbit takes 182.3 days. There also
seems to be a third (invisible) companion with an orbit of 1,350 days.
The two visible stars are at least 380 AU apart (5 times the diameter of Pluto's orbit).
Both are infra-red sources.
1820: 14.6 @ 146. Over 100 measurements.
The stars share common proper motion.
This star is a member of the Ursa Major moving stream.
From James Kaler's Star Notes:
Alcor is a fourth magnitude (4.01) white class A (A5) star with a temperature of 8,000
Kelvin and a luminosity 12 times that of the Sun. It appears coupled with Mizar, but is it
really a physical companion? We are still not sure.
Mizar itself is a quadruple star on the "double-double" theme (two double stars in
orbit about each other.) Precision parallaxes with the Hipparcos satellite show Mizar to
be 78.1 light years away, but Alcor to be 81.1 light years distant. Mizar and Alcor are
part of the Ursa Major cluster, whose core consists of the middle five stars of the Big
Dipper. A separation of over three light years, almost the distance between here and
Alpha Centauri, would make a gravitational pairing unlikely as the neighboring stars
-2-
Zone 71
would pull them apart. The measured errors, however, allow a separation as close as 0.7
light years. The errors in the distances are suspected of being greater than listed, and the
analysis of the orbit of Mizar A suggests that Mizar might actually be FARTHER than
Alcor! If they are actually at the same distance, their minimum separation is only 0.27
light years, making them close enough so that they could truly orbit, though with a long
period of three-quarters of a million years.
For a time Alcor was thought to be double, but it now appears that early astronomers
were fooled and that it is really single, rendering Mizar and Alcor together a "quintuple
star." While the Mizar stars are slow rotators with peculiar chemical compositions as a
result of element separation, Alcor is a rapid spinner (218 kilometers per second, over
100 times solar). As a result, its atmosphere is stirred and its composition normal. It is,
however, a slight pulsating variable.
The inner five stars of the Big Dipper are all at roughly the same distance and all are
normal hydrogen fusing main sequence dwarfs. Alcor's faintness next to the them is a
vivid reminder of the role that mass plays in the stars. Alcor's mass is around 1.6 times
that of the Sun. Alioth, on the other hand, with twice Alcor's mass, is almost 10 times
brighter!
On Mizar: One of the most famed stars of the sky, second magnitude (2.27) Mizar is
the Zeta star of Ursa Major, the Greater Bear, the second star in from the end of the
handle of the Big Dipper, and the Dipper's fourth brightest star.
In large part its fame comes from the coupling of the star with a nearby visual
companion, fourth magnitude Alcor, only 12 minutes of arc (a fifth of a degree) to the
northeast. The two, Mizar and Alcor, termed the "horse and rider" by the Arabians, are a
good test of minimal vision.
The star's Arabic name derives from a word meaning "the groin" of the celestial Bear
that plods silently around the north celestial pole (the name mistakenly drawn from
Merak, in the Dipper's bowl).
However even without Alcor, Mizar takes its place in the celestial hall of fame as the
first known "double star," one that consists of a pair of stars that orbit each other. Found
to be double in 1650, Mizar is a prime target for someone with a new telescope, as the
components are an easy 14 seconds of arc apart (at least 500 astronomical units), the two
taking at least 5,000 years to make their orbit about each other. More remarkably, each of
these two components is again double. The brighter of the two contains a very close pair
a mere 7 or 8 thousandths of a second of arc apart (an angle made by a penny at a
distance of 300 miles) that has an orbital period of 20.5 days, days; the fainter of them
contains a pair with a period of about half a year. Mizar is thus actually a quartet of stars,
a double-double.
It is moving through space together with its more-distant companion, Alcor. Mizar
and Alcor together therefore probably make a quintuple star, Alcor taking at least
750,000 years to make a single round trip around its quadruple companion. All of the
stars are similar, all "main sequence" hydrogen-fusing stars like the Sun, but of white
class A (the brighter both A2, the fainter probably both A5 or A7) with temperatures
-3-
Zone 71
ranging between around 7,500 and 9,000 degrees Kelvin and luminosities from 10 to 30
times solar.
The orbit of the brighter double that makes Mizar has been observed with a
sophisticated "interferometer" that makes use of the interfering properties of light.
Analysis shows the component stars to have masses 2.5 times that of the Sun; the masses
of the fainter pair are estimated at around 1.6 solar. The stars have odd chemical
abundances as a result of slow rotation, which allows for quiet atmospheres and chemical
separation. The brighter of the pair seen through the telescope is rich in silicon and
strontium, whereas the fainter is a "metallic line star" that is deficient in aluminum and
calcium but high in silicon and in rare earths like cerium and samarium.
Observations:
C8 at 104x. Webb saw A as gW.
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 8.40 inches; B = 8.40 inches.
Separation: AB = 1.93 miles; Aa = 3.94 feet; Bb = 16.9 feet.
Distance (LY): 78
Total luminosity (Suns): 82.1
h2649
HD 238213; SAO 28714
Rating: 3 E
Position: 1318+5420
A
B
Magnitude
10.21
10.64
Separation PA
—
—
21.3 345 +
Notes:
1880: 23.4 @ 344. 11 measurements.
Observations:
C11 at 115x.
-4-
Year
—
1991
Spectra
K0
Colors
Y
W
Zone 71
STF 1718
Hussey 643; SAO 28628
Rating: 4 E
Position: 1306+5100
A
B
Magnitude
9.50
10.07
Separation PA
—
—
13.1 272 =
Year
—
1991
Spectra
F8
Colors
W?
W?
Notes:
1831: 13.2 @ 272. 16 measurements. The stars share common proper motion.
Hussey doubled A (9.5m, 10.5m; 0.3 @ 203).
Observations:
C8 at 83x.
Espin 733
ADS 8869; HD 234031
Rating: 5 E
Position: 1321+5321
A
B
Magnitude
10.03
10.80
Separation PA
—
—
6.1 =
212 +
Year
—
1993
Notes:
1904: 6.1 @ 211. 4 measurements.
Observations:
C11 at 115x.
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 18.9 inches.
Separation: AB = 1.13 miles.
Distance (LY): 119
Total luminosity (Suns): 0.162
-5-
Spectra
G0
Colors
Y
bW
Zone 71
Moderate
OS 263
ADS 8843; HD 115477
Rating: 4 M
Position: 1317+5034
A
B
Magnitude
8.83
9.89
Separation PA
—
—
1.8 136 +
Year
—
1998
Notes:
1843: 2.2 @ 132. 44 measurements.
Observations:
C8 at 280x.
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 20.4 inches.
Separation: AB = 1.54 miles.
Distance (LY): 550
Total luminosity (Suns): 13
-6-
Spectra
G5
Colors
W
W
Zone 71
Zone 71, Map 2
Double Stars
Easy
STF 1747
ADS 8910; SAO 44617
Rating: 4 E
Position: 1328+4745
A
B
Magnitude
9.24
10.12
Separation PA
—
—
15.0 =
346 -
Year
—
1991
Spectra
K0
Colors
O
dO
Notes:
1831: 15.0 @ 347. 21 measurements. The stars share common proper motion.
Observations:
C8 at 104x.
h2634
SAO 44445
Rating: 5 E
Position: 1303+4744
A
B
Magnitude
9.55
13.14
Separation PA
—
—
30.9 60 =
Notes:
1906: 31.0 @ 60. 2 measurements.
Observations:
C11 at 115x.
-7-
Year
—
1908
Spectra
K5
Colors
Y
?
Zone 71
h2642
ADS 8793
Rating: 5 E
Position: 1308+4907
A
B
Magnitude
10.46
11.26
Separation PA
—
—
9.1 =
177 -
Year
—
1992
Spectra
F8
Colors
W
O?
Notes:
1830: 9.1 @ 178. 12 measurements.
Observations:
C11 at 115x.
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 17.1 inches.
Separation: AB = 8.52 miles.
Distance (LY): 600
Total luminosity (Suns): 2.71
Bemporad 4
Rating: 5 E
Position: 1308+4955
A
B
Magnitude
11.56
11.66
Separation PA
—
—
21.8 +
2-
Year
—
1991
Notes:
1904: 21.2 @ 22. 2 measurements.
Observations:
C11 at 115x.
Distance (LY): 62
Total luminosity (Suns): 0.014
-8-
Spectra
Colors
W
W
Zone 71
Zone 71, Map 3
Double Stars
Easy
Bemporad 6
Rating: 4 E
Position: 1334+5418
A
B
Magnitude
10.43
11.19
Separation PA
—
—
8.3 =
189 -
Year
—
1991
Spectra
Colors
W
W?
Notes:
1904: 8.3 @ 190. 6 measurements.
Observations:
C11 at 115x.
STF 1774 rej
C = h2676; ADS 8992; HD 119583; SAO 28860
Rating: 4 E
Position: 1343+5002
A
B
C
Magnitude
6.34
10.51
10.38
Separation
—
17.3 27.6-
PA
—
135 +
126 +
Year
—
1999
1991
Spectra
F8 V
Colors
W
?
?
Notes:
AB 1879: 17.9 @ 134. 10 measurements. Hipparcos/Tycho data show different
distances for these stars; they may be optical.
AC 1900: 29.7 @ 125. 7 measurements.
Observations:
C8 at 65x.
-9-
Zone 71
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 3.60 inches.
Separation: AB = 18.9 miles.
Distance (LY): 700
Total luminosity (Suns): 33
h2694
HD 121892; SAO 28940
Rating: 4 E
Position: 1357+5354
A
B
Magnitude
7.97
11.70
Separation PA
—
—
39.2 84 =
Year
—
1912
Spectra
K2
Colors
Y
pB
Notes:
1906: 39.8 @ 84. 2 measurements.
Observations:
C8 at 104x.
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 26.8 inches.
Separation: AB = 85.6 miles.
Distance (LY): 1,400
Total luminosity (Suns): 103
STF 1795
ADS 9077; HD 122200; SAO 28955
Rating: 4 E
Position: 1359+5307
A
B
Magnitude
6.83
9.96
Separation PA
—
—
7.9 +
2-
- 10 -
Year
—
1997
Spectra
A2 IV/V
Colors
Y
V
Zone 71
Notes:
1832: 7.6 @ 3. 19 measurements.
Observations:
C8 at 104x.
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 10.8 inches.
Separation: AB = 5.78 miles.
Distance (LY): 469
Total luminosity (Suns): 35
Moderate
STF 1770
ADS 8979; HD 118741; SAO 28819
Rating: 2 M
Position: 1338+5043
A
B
Magnitude
6.95
8.26
Separation PA
—
—
1.7 =
123 -
Year
—
1998
Spectra
M2 II/III
F3 III
Notes:
1831: 1.7 @ 125. 53 measurements. The primary is an infra-red source.
Observations:
C8 at 280x. Webb saw them as Y and W or O and rW.
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 1.20 inches.
Separation: AB = 4.69 miles.
Distance (LY): 1,770
Total luminosity (Suns): 720
- 11 -
Colors
O!
B!
Zone 71
Deep Sky Objects
Difficult
NGC 5225
Other Names: UGC 8540, H III 822
Rating: 5 D
Position: 1333+5129
Type : Gal
Surface brightness: 12.4
Class: S
Dimensions: 42"
Magnitude : 13.5
Observations:
C11 at 140x. Very, very faint and small, without a nucleus. It lies 10 min E of 3
bright field stars.
Radial velocity (km/sec): +4,622
- 12 -
Zone 71
Zone 71, Map 4
Reference Star
Eta UMa (85 UMa; Alkaid, "the chief of the mourners"; HD 120315; SAO 44752)
Position: 1348+4919
Mag : 1.85
Spectrum : B3 V Color : W
Assumed distance: 101 light years
Assumed luminosity (suns): 700
Notes:
Star A is a spectroscopic binary and an infra-red source.
The primary rotates at 205 kps, and the whole system is part of the Cas-Tau OB1
Association.
From James Kaler's Star Notes:
With a surface temperature of about 20,000 degrees Kelvin, Alkaid is one of the
hotter stars that can be seen with the naked eye, and therefore glows to us a soft bluewhite. Like the Sun, it is a "main-sequence" star that shines by fusing hydrogen into
helium in its core. However its mass of six times that of the Sun renders it both hotter.
Were Alkaid our Sun, we would have to be 25 times farther away to survive, almost to
the orbit of Neptune. The star is just below the temperature limit at which stars produce
strong X-rays as a result of shock waves in their winds, and is therefore only a weak
source of X-rays.
Double Stars
Easy
STF 1776
ADS 8996; HD 119348; SAO 44715
Rating: 4 E
Position: 1342+4613
A
B
Magnitude
8.53
8.57
Separation PA
—
—
7.3 =
18 -?
Year
—
1991
Spectra
G0
F0
Colors
W
W
Notes:
1832: 7.3 @ 200. 39 measurements. The stars share common proper motion.
Quadrant reversal?
- 13 -
Zone 71
Observations:
C8 at 65x.
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 17.5 inches; B = 10.8 inches.
Separation: AB = 9.11 miles.
Distance (LY): 800
Total luminosity (Suns): 40
h2680
ADS B6628
Rating: 4 E
Position: 1346+4524
A
B
Magnitude
10.07
11.51
Separation PA
—
—
23.7 +
148 -
Year
—
1991
Spectra
F8
Colors
W
W?
Notes:
1896: 22.2 @ 154. 6 measurements.
Observations:
C8 at 104x.
LDS 5800
SAO 44818
Rating: 4 E
Position: 1358+4853
A
B
Magnitude
9.81
11.29
Separation PA
—
—
41.6 =
356 =
Notes:
1902: 41.6 @ 356. 5 measurements.
Observations:
C11 at 115x.
- 14 -
Year
—
1991
Spectra
F8
Colors
W
B!
Zone 71
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 16.6 inches.
Separation: AB = 21.9 miles.
Distance (LY): 338
Total luminosity (Suns): 1.34
Moderate
A. G. 190
ADS 8964; HD 118376
Rating: 4 M
Position: 1336+4939
A
B
Magnitude
9.26
9.44
Separation PA
—
—
2.6 =
12 =
Year
—
1999
Spectra
K0
Colors
Y
Y
Notes:
1902: 2.6 @ 12. 36 measurements.
Observations:
C8 at 280x. It lies 12 min NNW of a 6.5m star.
STF 1758
ADS 8940; HD 117963; SAO 44650
Rating: 5 M
Position: 1333+4909
A
B
Magnitude
7.98
8.24
Separation PA
—
—
3.5 294 -
Year
—
1999
Spectra
G0
Colors
W
W
Notes:
1832: 4.2 @ 311. 66 measurements. The stars have different proper motions.
Observations:
C8 at 206x. It lies 18 min WNW of 5m 24 CVn. Webb saw the primary as W, Bird
saw it as Y.
- 15 -
Zone 71
Scale Model (in which the Sun is a baseball):
Component
Diameter, in
A
16.9
B
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 16.9 inches.
Separation: AB = 1.38 miles.
Distance (LY): 254
Distance, mi
na
1.38
Total luminosity (Suns): 4.5
Espin 2646
ADS 8945; SAO 44658
Rating: 5 M
Position: 1334+4648
A
B
Magnitude
8.81
12.50
Separation PA
—
—
8.9 343 -
Year
—
1979
Spectra
G5
Colors
yW
?
Notes:
1911: 9.4 @ 344. 2 measurements.
Observations:
C11 at 115x.
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 20.3 inches.
Separation: AB = 11.8 miles.
Distance (LY): 850
Total luminosity (Suns): 17.6
Bur 802
ADS 9030; HD 120475; SAO 44759
Rating: 5 M
Position: 1349+4821
A
B
Magnitude
7.50
11.69
Separation PA
—
—
3.5 +
225 +
- 16 -
Year
—
1992
Spectra
F0 IV
Colors
Y
?
Zone 71
Notes:
AB 1881: 3.4 @ 224. 14 measurements.
Observations:
C8 at 206x.
Scale model (in which the Sun is the size of a baseball):
Diameter: A = 8.40 inches.
Separation: AB = 1.79 miles.
Distance (LY): 328
Total luminosity (Suns): 8.44
Deep Sky Objects
Easy
NGC 5194
Rating: 1 E
Other Names: Whirlpool Galaxy; 4C 47; UGC 8493; Arp 85, M51
Astronomical Leage Program: Messier Club
Position: 1330+4712
Type : Gal
Surface brightness: 12.6
Class: SA(s)bc pec I-II
Dimensions: 6' x 10'
Magnitude : 8.7
PA: 163
Notes:
Messier discovered it on October 13, 1773 while observing the Comet of 1773 and
added it to his catalog on January 11, 1774. He wrote, "it is double, each having a bright
center, separated by 4'35". The two atmospheres touch each other. One is fainter than
the other."
It was named "the Whirlpool" by Lord Rosse, who observed it with his 72-inch
"Leviathin" telescope in 1845. In fact, the spiral pattern he noticed seemed to confirm a
popular (but erroneous) theory of planetary system formation put forward by the French
philosopher LaPlace, called the "nebular hypothesis", which resulted in astronomers
thinking that the spiral nebulae were all condensing proto-star systems within the Milky
Way. It was not until 1929 that Hubble, using his own work and that of several others in
the 1910’s and 20’s, proved that the spiral nebulae were actually Milky Ways in their
own right but at vast distances.
- 17 -
Zone 71
It is 100,000 light years in diameter and weighs in at about 160 billion solar masses.
The center harbors a black hole with 2 million solar masses that is 100 light years in
diameter. Infrared studies show the arms make three complete laps around the nucleus.
It is also a Seyfert galaxy.
The "connecting bridge" is an illusion as high magnification photos show that the
satellite galaxy actually lies behind M51.
Observations:
C8 at 104x. It is mottled and splotchy; even the spiral arms are discernible (at high
power). (Both Messier and Herschel missed the spiral structure.) The connecting bridge
is also visible. At the Texas Star Party in 2001, I got the chance to view M51 through the
36-inch Cassegrain reflector at McDonald Observatory and clearly saw the two spiral
arms and bridge (or arm extension) that cuts in front of NGC 5195. There is a 12m star
just SW of the nucleus. Steve
Coe points out that this has
been turned in as a supernova
many, many times, so don't
bite the bait!
C11 at 193x. The nucleus
looks comma-shaped; the
galaxy is heavily mottled and
in moments of good seeing,
spiral structure is suspected.
Model (where the Sun is a
baseball):
Its diameter would be 33
million miles.
Distance (LY): 35,000,000
Luminosity (suns):
31,800,000,000
Radial velocity (km/sec):
+546
NGC 5194 (M51, the Whirlpool)
Galaxy (SA(s)bc pec I-II)
Observed with C8 on 5/20/95; s7, t6
Magnification: 100x
- 18 -
Zone 71
NGC 5195
Other Names: UGC 8494, H I 186
Astronomical League Program: Herschel 400 Club
Rating: 4 E
Position: 1330+4716
Type : Gal
Surface brightness: 13.1
Class: I0 pec
Dimensions: 2'
Magnitude : 11.0
PA: 79
Notes:
Photos suggest that it actually lies behind M51.
It too is a Seyfert galaxy.
It was discovered by P. Mechain on March 20, 1781. Messier mentions it in his 1781
catalog.
SN 19545A was detected in this galaxy by Milton Humason.
Observations:
C8 at 83x. Bright.
C11 at 193x. Very bright and round, srongly concentrated.
Model (where the Sun is a baseball):
Its diameter would be 7 million miles.
Distance (LY): 36,000,000
Radial velocity (km/sec): +650
Luminosity (suns): 4,100,000,000
Moderate
NGC 5377
Other Names: UGC 8863, H I 187
Rating: 3 M
Position: 1356+4714
Type : Gal
Surface brightness: 13.6
Class: (R)SB(s)a
Dimensions: 3' x 0.6'
Notes:
This galaxy produced supernova 1992H (type IIp).
- 19 -
Magnitude : 12.0
PA: 20
Zone 71
Observations:
C8 at 104x. Bright, with a suggestion of central lobes or knots. It magnifies poorly,
though. It has a NE-SW axis.
Distance: 85,000,000 light years
Radial velocity (km/sec): +1,951
Luminosity: 9,000,000,000 Suns
Difficult
NGC 5173
Other Names: H III 672
Rating: 4 D
Position: 1329+4635
Type : Gal
Surface brightness: 11.9
Class: E0
Dimensions: 1.0' x 1.0'
Magnitude : 12.1
Observations:
C8 at 104x. A round ball of mist with no condensation.
Radial velocity (km/sec): +2,506
NGC 5198
Other Names: H II 689
Rating: 5 D
Position: 1330+4640
Type : Gal
Surface brightness: 12.9
Class: E1-2:
Dimensions: 2.0' x 1.7'
Magnitude : 11.8
Observations:
C8 at 104x. Averted vision and tube movement helped bring in this indistinct glow.
Three very faint stars frame it.
Distance: 110,000,000 light years
Radial velocity (km/sec): +2,590
Luminosity: 18,100,000,000 Suns
- 20 -
Zone 71
Zone 71 Mini-Catalog
Double Stars
Designation
Position
Rating
Map
Zeta UMa
1324+5456
2E
1
h2649
1318+5420
3E
1
STF 1718
1306+5100
4E
1
STF 1747
1328+4745
4E
2
Bemporad 6
1334+5418
4E
3
STF 1776
1342+4613
4E
4
STF 1774 rej
1343+5002
4E
3
h2680
1346+4524
4E
4
h2694
1357+5354
4E
3
LDS 5800
1358+4853
4E
4
STF 1795
1359+5307
4E
3
h2634
1303+4744
5E
2
Bemporad 4
1308+4955
5E
2
h2642
1308+4907
5E
2
Espin 733
1321+5321
5E
1
STF 1770
1338+5043
2M
3
OS 263
1317+5034
4M
1
A. G. 190
1336+4939
4M
4
STF 1758
1333+4909
5M
4
Espin 2646
1334+4648
5M
4
Bur 802
1349+4821
5M
4
Component
A
B
A
B
A
B
A
B
A
B
A
B
A
B
C
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
A
B
- 21 -
Mag
2.23
3.85
10.21
10.64
9.5
10.07
9.24
10.12
10.43
11.19
8.53
8.57
6.34
10.51
10.38
10.07
11.51
7.97
11.7
9.81
11.29
6.83
9.96
9.55
13.14
11.56
11.66
10.46
11.26
10.03
10.8
6.95
8.26
8.83
9.89
9.26
9.44
7.98
8.24
8.81
12.5
7.5
11.69
Separation
—
14.4 —
21.3 —
13.1 —
15.0 =
—
8.3 =
—
7.3 =
—
17.3 27.6—
23.7 +
—
39.2 —
41.6 =
—
7.9 +
—
30.9 —
21.8 +
—
9.1 =
—
6.1 =
—
1.7 =
—
1.8 —
2.6 =
—
3.5 —
8.9 —
3.5 +
PA
—
153 +
—
345 +
—
272 =
—
346 —
189 —
18 -?
—
135 +
27.6—
148 —
84 =
—
356 =
—
2—
60 =
—
2—
177 —
212 +
—
123 —
136 +
—
12 =
—
294 —
343 —
225 +
Zone 71
Deep Sky Objects
Object
NGC 5194
NGC 5195
NGC 5377
NGC 5173
NGC 5198
NGC 5225
Position
1330+4712
1330+4716
1356+4714
1329+4635
1330+4640
1333+5129
Rating
1E
4E
3M
4D
5D
5D
Map
4
4
4
4
4
3
Specifications
Surface
Type
Mag
Br
Gal (SA(s)bc pec I-II)
8.7
12.6
Gal (I0 pec)
11.0
13.1
Gal ((R)SB(s)a)
12.0
13.6
Gal (E0)
12.1
11.9
Gal (E1-2:)
11.8
12.9
Gal (S)
13.5
12.4
- 22 -
Pop.