Descriptive information was drawn from Burnham's Celestial Handbook by Robert Burnham, Jr. (1978, Dover Publications, Inc.), "Portraits of Stars and their Constellations" by Dr. J. Kaler, "Cosmobrain", and "The Bright Star Catalogue", 5th Revised Edition by D. Hoffleit and W. H. Warren, Jr.

Basic information about a star can be summarized by a couple pieces of information: its brightness and color.

magnitude
A star's apparent brightness is given as a number on the magnitude scale. The lower the number, the brighter the star and a one magnitude difference appears to be about a factor of two brighter or dimmer. For example, a -1.0 magnitude star appears twice as bright as a 0.0 magnitude star; 0.0 about twice as bright as 1.0, and so on. It happened that, when this difference was measured less subjectively, the difference was actually about 2.5 times.
spectral type
A star's color is related to a its surface temperature which is central to defining its spectral type: O, B, A (hot and blue-white), F, G (yellow like our Sun), K and M (cooler and redder). There are other special classes for special cases. These broad catagories are subdivided into ten subcatagories: 0 - 9. So a B9 and A0 are pretty close in color and temperature. Likewise, an A9 and F0 are too. There are countless other subdivisions but these will be ignored here.

Binary and multiple stars are described with three additional pieces of information.

letter ID
The primary star is typically, but not always, the brightest star of the group and is typically, but not always (you've caught on by now that, historically, there has been some variation in following these rules so, from here on, just assume there is always an exception), given the letter A. The other stars in the group are given letters B, C, D, …, in order of brightness.
separation
The small angles between the other stars in the group relative to the primary are measured in seconds of arc. The seconds of arc measurement is abbreviated by ", the double quote character or the word arcsec.
position angle or P.A.
The P.A. of a companion to the primary star is the angle measured from north to the east. That's counter-clockwise in these pictures. Imagine a clock face centered and superimposed on the primary star of the group. A P.A. of 90° means the star is at the 9 o'clock position relative to the primary and 210° is the 5 o'clock position (see the associated figure).


η Cassiopeiae 0h 49.1m +57° 49´ Cassiopeia 3.5, 7.2 Sky Atlas 2000.0
chart 1
eta_cas
25.0 mm eyepiece plus barlow; 3.0x telephoto, 4.0x digital zoom (840.0×)
This image is an average of twenty-one 1/2 sec - f/4.9 - ISO 200 photos. This image is at a non-standard magnification.
NexStar #166; SAO 21732

The primary is a G0 star and the companion, a M0 star separated by 13" at P.A. 319°. Note that the ruddy color of the companion is quite evident. There are several other members to this system but all are either too faint or too far away to appear in this photo.

γ Arietis 1h 53.5m +19° 18´ Aries 3.9, 3.9 Sky Atlas 2000.0
chart 4
gamma_ari
25.0 mm eyepiece; 3.0x telephoto, 4.0x digital zoom (600.0×)
This image is an average of 4 1/4 sec - f/4.9 - ISO 400 photos. This image is at a non-standard magnification.
NexStar #346 SAO 92680

γ Arietis is an A5 primary and an unusual Si (silicon rich) companion separated by 7.4" at P.A. of 1°. A pretty and evenly matched pair.

γ Andromedae 2h 03.9m +42° 20´ Andromeda 2.1, 4.8 Sky Atlas 2000.0
chart 4
gamma_and
25.0 mm eyepiece; 3.0x telephoto (150.0×)
This image is an average of five 1/2 sec - f/4.9 - ISO 400 photos
Almach; NexStar #389 and 390; SAO 37734 and 37735

γ Andromedae is considered one because of its color contrast and the ability to separate the pair in a small telescope. The primary is a K3 while the secondary is a B8 separated by 10" at a P.A. of 63°. It should not be a surprise that both members are each close doubles themselves.

ι Cassiopeiae 2h 29.1m +67° 24´ Cassiopeia 4.5, 6.9 Sky Atlas 2000.0
chart 1
iota_cas
25.0 mm eyepiece plus barlow; 3.0x telephoto, 4.0x digital zoom (840.0×) This image is an average of two 1/2 sec - f/4.9 - ISO 200 photos. This image is at a non-standard magnification.
NexStar #463; SAO 12298

ι Cassiopeiae is tough with my equipment under these conditions but I believe this photo shows the A5 primary and the metal rich companion star at 2.8" and P.A. 231°. If one looks closely, a 9.1 magnitude third member, separated by 7.4" at P.A. 116° is just visible. The smaller image to the right is a slightly enhanced version of the photo making the third member a little more evident.
iota_cas_hi_res

Polaris 2h 31.8m +89° 15´ Ursa Minor 2.1, 9.1 Sky Atlas 2000.0
chart A4
polaris
25.0 mm eyepiece; 3.0x telephoto (150.0×)
This image was create by averaging four 1/4 sec - f/2.8 - ISO 400 photos, then enhancing the contrast.
α Ursae Minoris; NexStar #470; SAO 308

Polaris is the north star, a Cepheid variable and a challenging multiple star. The brightest companion, just visible in this photo, is separated by 18.4" at P.A. 225°. Some folks have noted that these two plus other nearby faint stars (too faint to be seen in this photo) form a little ring of stars which they've nicknamed the "engagement ring".

32 Eridani 3h 54.3m -2° 57´ Eridanus 4.7, 5.9 Sky Atlas 2000.0
chart 11
32_eri
25.0 mm eyepiece; 3.0x telephoto, 4.0x digital zoom (600.0×)
This image is an average of twenty-two 1/2 sec - f/4.9 - ISO 200 photos.
NexStar #781 or #6234; SAO 130806 or 130805

What a delightful surprise. 32 Eridani shows a beautiful color contrast between its G8 primary and its A2 secondary which is separated by 6.9" at P.A. 349°.

R Leporis 4h 59.6m -14° 48´ Lepus 8.1 Sky Atlas 2000.0
chart 11
r_lep
25.0 mm eyepiece with reducer-corrector (31.5×) An average of three 8 sec - f/2.8 - ISO 400 photos.
Hind's Crimson Star; NexStar #1054; SAO 150058

In the center of the image is R Leporis, known for its smokey red or coppery color. R Leporis is a long period variable and is a member of a small class of stars known as carbon stars, spectral type C6, which display unusually high carbon abundances in their atmosphere. This is a star in the last stages of its life. R Leporis started out as a B star of less than five solar masses but it has used up much of it hydrogen fuel. In doing so, it has created a carbon-oxygen core with shells of helium fusing to make more carbon and hydrogen creating more helium. Convection, like in our own Sun, dredges up some of this new carbon giving R Leporis its strong carbon signature. At this stage, its outer layers have expanded to the radius of our asteroid belt, and cooled giving it the distinctive red color. Even now, R Leporis is varying like another famous star, Mira, and shedding its outer layers in a massive stellar wind. This wind will form a planetary nebula leaving the white dwarf core of the star to cool over billions of years.

θ¹ Orionis 5h 35.3m -5° 23´ Orion 5.1, 6.4, 5.0, 5.1 Sky Atlas 2000.0
chart B2
theta_ori
25.0 mm eyepiece with reducer-corrector; 3.0x telephoto, 4.0x digital zoom (378.0×)
A single 8 sec - f/4.9 - ISO 400 photo. This image is at a non-standard magnification.
Trapezium; NexStar #1231 or 1232; SAO 132314 and 132321

I took this picture as a test of the focus and was struck by its errie look. θ¹ Orionis is the group four stars near the center. Most commonly, the four stars are labeled from west to east, i.e. from right to left:
  1. on the right, is a B0 and an eclipsing binary with a period of 65.4 days while dropping in brightness by about 1 magnitude,
  2. at the top, is a also a B0 star and eclipsing binary with a period of 6.5 days with a 1 magnitude change,
  3. at the bottom, is an O6 star and, as the brightest of the four, conventionally be considered the primary, and
  4. on the left, is another B0 star.
These young stars were born in and are the source of illumination for the Orion Nebula.

σ Orionis 5h 38.7m -2° 36´ Orion 3.7, 6.3, 6.7, 8.8 Sky Atlas 2000.0
chart 11
sigma_ori
25.0 mm eyepiece with reducer-corrector; 3.0x telephoto (94.5×)
Created by averaging three 1/2 sec - f/4.9 - ISO 400 photos.
NexStar #1259; SAO 132406

Three members of this system are readily evident:

AB. the O9 primary,
D.   spectral type B2, separated by 12.9" at P.A. 84° and
E.   42" distant at P.A. 61°.

If I zoom in, you can just see member C, an A2 dwarf, located just 11.2" away at P.A. 236°.

AB is actually a double which can't be split with this equipment. AB are notable because both stars are large, 18 and 13 solar masses respectively, making it one of the most massive visual binaries in our sky. E is an unusual "helium rich" star.

h 3780 5h 39.3m -17° 51´ Lepus 6.4, 7.7, 8.2, 8.9, 9.5 Sky Atlas 2000.0
chart 11
h_3780
25.0 mm eyepiece with reducer-corrector; 3.0x telephoto (94.5×)
Created by averaging three 4 sec - f/4.9 - ISO 400 photos.
NexStar #6581; SAO 150652

h 3780 has six components, of which, four are visible in this image:

AB. the primary,
C.   89.2" distant at P.A. 136°,
E.   76.1" distant at P.A. 7° and
F.   126.5" away at P.A. 299°.

If the contrast is greatly enhanced, one can just detect D, 89.2" away at P.A. 102°, which appears centered in the smaller image, and G, 60.3" at P.A. 50°.

γ Leporis 5h 44.5m -22° 27´ Lepus 3.6, 6.3 Sky Atlas 2000.0
chart 19
gamma_lep
25.0 mm eyepiece with reducer-corrector, 3.0x telephoto (94.5×)
Created by averaging three 4 sec - f/4.9 - ISO 400 photos.
NexStar #1281; SAO 170759

The K2 companion is separated from the F6 primary by 94.9" at P.A. 351°. A wide pair with a nice color contrast.

β Monocerotis 6h 28.8m -7° 02´ Monoceros 4.7, 5.2, 6.2 Sky Atlas 2000.0
chart 11
beta_mon
25.0 mm eyepiece with reducer-corrector, 3.0x telephoto (94.5×)
Created by averaging three 1/2 sec - f/4.9 - ISO 400 photos.
NexStar #1513 or 1514; SAO 133316 and 133317

All three stars are spectral type B3. The wider pair is separated by 7.4" at P.A. 315°. The brighter star to the north-east is actually the other pair, 2.8" at P.A. 108°, which I could not separate under these conditions.

12 Lyncis 6h 46.2m +59° 27´ Lynx 5.4, 6.0, 7.3 Sky Atlas 2000.0
chart 1
12_lyn
25.0 mm eyepiece with reducer-corrector, 3.0× telephoto (94.5×)
A combination of five 2 sec - f/4.9 - ISO 400 photos with the contrast modified to better show the separation. This image is at a non-standard magnification.
NexStar #1597; SAO 25939

The primary is an A3 star. The B companion is at P.A. 74.0°, 1.9". The C member is at P.A. 309.0°, 8.7". I'm surprise this turned out as good as it has. This night was poor at best. However, I could see the C component through the eyepiece and went ahead and gave it a shot. B is in the glare of the primary but reasonably distinct. The C is just visible to the northwest.

145 Canis Majoris 7h 16.6m -23° 19´ Canis Major 4.8, 6.0 Sky Atlas 2000.0
chart 19
145_cma
25.0 mm eyepiece with reducer-corrector, 3.0x telephoto (94.5×)
Created by averaging three 4 sec - f/4.9 - ISO 400 photos.
NexStar #1765; SAO 173349

Although not as bright, note the much longer exposure time, 145 Canis Majoris is often called the Winter Albireo because of the striking color contrast of this pair. With a large separation, 26.8" at P.A. 52°, the orange, K3, primary and blue, B-type, secondary make for a beautiful pair.

α Geminorum 7h 34.6m +31° 53´ Gemini 2.0, 2.9 Sky Atlas 2000.0
chart 5
alpha_gem
25.0 mm eyepiece with reducer-corrector, 3.0x telephoto; 4.0x digital zoom (378.0×)
A single 1/125 sec - f/4.9 - ISO 400 photo. This image is at a non-standard magnification.
Castor; NexStar #1865; SAO 60198

A very evenly matched A1 and A7 pair separated by 4.3" at P.A. 60°. Their brightness makes them a challenge. Fortunately, they'll be getting further apart until about 2100 A.D. There is a third member, C also know as YY Gem, not seen in this photo, which is both an eclipsing binary and a flare star.

κ Puppis 7h 38.8m -26° 48´ Puppis 3.8, 4.0 Sky Atlas 2000.0
chart 19
kappa_pup
32.0 mm eyepiece with reducer-corrector, 3.0x telephoto (73.8×)
Created by averaging four 1/4 sec - f/4.9 - ISO 400 photos.
NexStar 1883; SAO 174198

An almost perfectly matched B6 pair separated by 9.8" at P.A. 318°. A 13.8 magnitude third member is not visible in this photo.

ζ Cancri 8h 12.2m +17° 39´ Cancer 5.6, 6.0, 6.3 Sky Atlas 2000.0
chart 12
zeta_cnc
25.0 mm eyepiece with reducer-corrector, 3.0x telephoto (94.5×)
Created from a single 4 sec - f/4.9 - ISO 400 photo.
Tegmine or Tegmeni; NexStar #2055 and 2056; SAO 97645 and 97646

A and B, F8 and F7, are separated by less than 1", too close to separate in this equipment. At a distance of 83 l.y., this implies these two stars are only 19 AU apart, roughly the distance of Uranus from the Sun. The third member, a G5 separated by 6.6" at P.A. 83° orbits around AB. Recent reseach indicates that C is itself a binary with pair of very cool, dim M type stars.

ι Cancri 8h 46.7m +28° 46´ Cancer 4.0, 6.6 Sky Atlas 2000.0
chart 6
iota_cnc
25.0 mm eyepiece with reducer-corrector, 3.0x telephoto (94.5×)
Created by averaging three 1/2 sec - f/4.9 - ISO 400 photos.
NexStar #2216; SAO 80416

ι Cancri's wide separation and color contrast make it a beautiful binary. The primary is a light yellow G7 and the secondary is a blue A3 dwarf star with a 30.6" separation at a 307° P.A.

γ Leonis 10h 20.0m +19° 51´ Leo 2.6, 3.8 Sky Atlas 2000.0
chart 6
gamma_leo
32.0 mm eyepiece with reducer-corrector, 3.0x telephoto (73.8×)
Created by averaging three 1/60 sec - f/4.9 - ISO 400 photos.
NexStar 2560 and 2561; SAO 81298 and 81299

The brightest members are K1 and G7 making a soft, golden pair separated by 4.5" at P.A. 126°. The other two members are three arc minutes away. The small distance between starts to become a challenge with average seeing, so a much shorter exposure was used to separate this pair.

54 Leonis 10h 55.6m +24° 45´ Leo 4.3, 6.3 Sky Atlas 2000.0
chart 6
54_leo
32.0 mm eyepiece with reducer-corrector, 3.0x telephoto (73.8×)
Created by averaging three 1/8 sec - f/4.9 - ISO 400 photos.
NexStar 2683; SAO 81583

Another evenly matched A1 and A2 pair separated by 6.3" at P.A. 110°. A shorter exposure was used to separate this pair.

Lalande 21185 11h 03.3m +35° 58´ Ursa Major 7.5 Sky Atlas 2000.0
charts 6, 7
Lalande 21185
25.0 mm eyepiece with reducer-corrector (31.5×)
I removed a flatfield and enhanced the contrast on three 20 sec - f/2.8 - ISO 400 photos. I then combined the photos. Move the cursor over the photo to see the finder chart from Burnham's superimposed upon the photo.


Lalande 21185 is the brightest red dwarf visible from the northern hemisphere because it is one of the nearest stars to Earth at only 8.3 l.y. It currently ranks as the seventh nearest behind the Alpha Centauri triplet, Barnard's Star, Wolf 359 and a newly discovered, faint red dwarf in Aries. Because it is so near, Lalande also has a high proper motion, meaning it appears to be moving across our sky quickly, of 4.78 arcsec per year in P.A. 187°. It is an M2 star which appears to have at least three Jupiter-sized planets.

ξ Ursae Majoris 11h 18.2m +31° 32´ Ursa Major 4.3, 4.8 Sky Atlas 2000.0
chart 6
xi_uma
12.0 mm eyepiece with reducer-corrector, 3.0× telephoto (312.5×)
This is a combination of four 1/4 sec - f/4.9 - ISO 400 photos, then the contrast was enhanced. This image is at a non-standard magnification.
Alula Australis (from the Arabic Al Kafzah al Ula meaning "the first of spring"; NexStar #2745; SAO 62484

ξ Ursae Majoris is a nicely matched F9 primary and a G9 companion star separated by 1.9" at P.A. 250°. ξ Ursae Majoris is relatively easy to find but a challenge for my equipment on most nights. By 2023, the separation will slowly widen to its maximum of 3.1" and the companion will have swing around to the primary's lower left.

Groombridge 1830 11h 53.0m +37° 43´ Ursa Major 6.4 Sky Atlas 2000.0
chart 6
Groombridge 1830
25.0 mm eyepiece with reducer-corrector (31.5×)
I removed a flatfield and enhanced the contrast on four 20 sec - f/2.8 - ISO 400 photos. I then combined the photos. Move the cursor over the photo to see the finder chart from Burnham's superimposed upon the photo.


Groombridge is a high proper motion star, meaning it appears to move across the sky quickly, with a rate of 7.042 arcsec in P.A. 145.5° This makes it third fastest behind Barnard's Star and Kapteyn's Star. Being a high proper motion implies that Groombridge 1830 is nearby, 29.7 l.y., but, of more interest, it really is moving quickly through space. That's because Groombridge 1830 is a Population II star just passing through our part of the galaxy.

Population I stars are stars like our Sun. They exist in the disk of our galaxy, i.e. the Milky Way, and all have about the same proportions of different elements. Population II, or Pop. II stars are distributed spherically around the center of our galaxy. They also contain much smaller quantities of elements heavier than hydrogen and helium than do Pop. I stars. Groombridge 1830, for example, which is classified as a G8 star, very similar to our G2 Sun, has only 1/30 the quantities of these heavier elements compared to our Sun. If none of the Pop. II stars have these elements, they must have formed before these elements were created in other stars. Therefore, Pop. II stars must have formed very early in the history of our galaxy.

If Pop. II stars formed first, why are they Pop. II and not I? Because astronomers studied stars like our Sun for a while before they realized stars like Groombrigde 1830 existed. At first, they didn't understand why they were different so the first group of stars were called Pop. I and the second group, Pop. II.

24 Comae Berenices 12h 35.1m +18° 23´ Coma Berenices 5.1, 6.3 Sky Atlas 2000.0
chart 14
24_com
25.0 mm eyepiece with reducer-corrector, 3.0x telephoto (94.5×)
Created by averaging three 1/4 sec - f/4.9 - ISO 400 photos.
NexStar #2994; SAO 100160

Another pair with a beautiful color contrast both in the eyepiece and in photographs. The primary is spectral type K2 and the secondary, at 20.1", P.A. 270°, is an A9.


γ Virginis 12h 41.7m -1° 27´ Virgo 3.4, 3.5 Sky Atlas 2000.0
chart 14
gamma_vir
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
An average of five 1/30 sec - f/4.9 - ISO 400 photos. This image is at a non-standard magnification.
Porrima; NexStar #3016; SAO 138892

γ Virginis is reputed to be a wonderful, evenly matched pair of F0 stars but, through about 2014, the pair are so close they can not be separated (0.6" at P.A. 212° in 2005). After that, the separation widens until reaching a maximum of about 6.2" in 2094. I don't recall having looked at this pair before but, in just a few years, I'll be able to split them and see for myself. γ Virginis is actually a multiple system but the other members are much fainter and widely separated.

Y Canum Venaticorum 12h 45.1m +45° 26´ Canes Venatici 5.2 Sky Atlas 2000.0
chart 7
y_cvn
25.0 mm eyepiece with reducer-corrector, 3.0x telephoto (94.5×)
Created by averaging four 1/4 sec - f/4.9 - ISO 400 photos.
La Superba; NexStar #3025; SAO 44317

Y Canum Venaticorum is another of the strikingly red, carbon rich stars in the later stages of its life (see R Leporis for a more complete discussion). In fact, because of its spectrum not its color, it is sometimes called La Superba. Y Canum Venaticorum is a C7 type and its color is obvious in the eyepiece. Its only failing is that there is no comparable normal star in the eyepiece field to accentuate its unusual appearance.

α Canum Venaticorum 12h 56.0m +38° 19´ Canes Venatici 2.9, 5.6 Sky Atlas 2000.0
chart 7
alpha_cvn
25.0 mm eyepiece with reducer-corrector, 3.0x telephoto (94.5×)
Created by averaging three 4 sec - f/4.9 - ISO 400 photos.
Cor Coroli; NexStar #3070 or #3071; SAO 63256 and 63257

Commonly called Cor Coroli, meaning "the Heart of Charles", it was allegedly named such by Edmund Halley to honor Charles II; however, evidence exist that this name is older and was so named to honor Charles I (see Burnham, Vol. 1, p. 359 for a more complete explanation).

Cor Coroli is a popular binary for folks with small telescopes because the secondary is often described as being lilac in color when compared to the pure white primary. The primary is an A0 star and is known to have an exceptionally strong magnetic field. The secondary, located at 19.3", P.A. 229.0°, is sometimes listed as an F0 or Si type because of an overabundance of rare earth elements.

Mizar 13h 23.9m +54° 56´ Ursa Major 2.2, 3.9 Sky Atlas 2000.0
chart 2
mizar
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging five 1/4 sec - f/4.9 - ISO 400 photos.
ζ Ursa Majoris; NexStar #3151, #3152 or #3158; SAO 28737, 28738 and 28751

Mizar and Alcor (A and C) are undoubtedly the most famous "double" star in the sky. One is able to split this pair with sharp eyes. This was also the first binary to be identified as such. Three stars are visible through a small telescope forming an easy triplet of white stars with spectral types A = A1, B = A1 and C = A5. The A-B separation is 14.3" with P.A. 153.0°; A-C is 707.5" at P.A. 71.0°. Mizar has been identified as a binary because by examining the star's spectra but this pair is too close to separate.

κ Bootis 14h 13.5m +52° 00´ Bootes 4.6, 6.6 Sky Atlas 2000.0
chart 7
kappa_boo
25.0 mm eyepiece with reducer corrector, 3.0x telephoto, 4.0x digital zoom (378.0×)
This is a combination of five 1/2 s - f/4.9 - ISO 400 photos.
Asellus Tertius; NexStar #3307 and #8302; SAO 29046 and 29045

κ Bootis is an A8 primary with an F1 companion at P.A. 235.0° separated by 13.5". A pretty pair for smaller telescopes.

ε Bootis 14h 45.0m +27° 04´ Bootes 2.3, 4.5 Sky Atlas 2000.0
chart 7
epsilon_boo
12.0 mm eyepiece with reducer-corrector, 3.0x telephoto (196.9×)
Created by averaging four 1/8 sec - f/4.9 - ISO 400 photos and then the contrast was enhanced. This image is at a non-standard magnification.
NexStar #3413; SAO 83500

ε Bootis is, for me, a challenge because of their smaller separation, 2.9" at P.A. 343°, with larger magnitude difference. A 12 magnitude third member lies almost 3 arcmin away.

ξ Bootis 14h 51.4m +19° 06´ Bootes 4.8, 7.0 Sky Atlas 2000.0
chart 7
xi_boo
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
A single 1/8 sec - f/4.9 - ISO 400 photo. This image is at a non-standard magnification.
NexStar #3445; SAO 101250

A pretty yellow G8 primary with an pale orange K5 companion. This pair is 6.5" apart at P.A. 315°. There are several other members of this multiple too faint or far to be seen in this photo.

δ Boötis 15h 15.5m +33° 19´ Boötes 3.5 Sky Atlas 2000.0
chart 7
delta Bootis 2010-05-30 δ Boötis – 49 Boötis – SAO 64589 – NexStar # 3526

2010-05-30 White balance = 6000K (Cloudy)
Noise reduction = Off
negative projection (204×)
Created from seven 8 s - ISO 100 photos. I removed a dark frame from each photo, averaged them together, enhanced the contrast, rotated to north-up, cropped the photo and reduced its size 75%.

A yellowish, 3.6 mag., G8 primary and an easy 7.9 mag. companion at 103.4" at P.A. 78.0°. A pretty pair in any telescope.



μ Bootis 15h 24.5m +37° 23´ Bootes 4.3, 7.0, 7.6 Sky Atlas 2000.0
chart 7
mu_boo
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging seven 1/4 sec - f/4.9 - ISO 400 photos. This image is at a non-standard magnification.
Alkalurops; NexStar #3568; SAO 64686

BC pair are separated from the F2 primary by 106.8" at P.A. 170°. B-C are separate by 2.2" at P.A. 8°.

ζ Coronae Borealis 15h 39.4m +36° 38´ Corona Borealis 5.0, 6.0 Sky Atlas 2000.0
chart 7
zeta_crb
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging ten 1/4 sec - f/4.9 - ISO 400 photos. This image is at a non-standard magnification.
NexStar #3628 and 3629; SAO 64833 and 64834

This pair are separated by 6.3" at P.A. 306°. This binary is challenging because the stars are faint and relatively close together.

ξ Scorpii 16h 04.4m -11° 22´ Scorpius 4.8, 7.3 Sky Atlas 2000.0
chart 15
xi_sco
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging three 1/4 sec - f/4.9 - ISO 400 photos. This image is at a non-standard magnification.
NexStar #3733; SAO 159665

The primary is a yellowish F5 with a secondary separated by 7.6" at P.A. 46°. The primary is an unresolved double.

β Scorpii 16h 05.4m -19° 48´ Scorpius 2.6, 4.9 Sky Atlas 2000.0
chart 22
beta_sco
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging three 1/2 sec - f/4.9 - ISO 400 photos.
Graffias; NexStar #3735 or 3736; SAO 159682 and 159683

A blue-white primary with a matching but fainter secondary star 13.6" distant at P.A. 20°. Like many others, this is actually a multiple star system, not just a binary.

κ Herculis 16h 08.1m +17° 03´ Hercules 5.1, 6.2 Sky Atlas 2000.0
chart 15
kappa_her
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging five 1/2 sec - f/4.9 - ISO 400 photos.
NexStar #3748; SAO 101951

A pretty yellow G8 primary with an pale orange K1 companion separated by 27.2" at P.A. 13°. Difficult only because κ Herculis is faint.

ν Scorpii 16h 12.0m -19° 28´ Scorpius 4.4, 5.4 (AB)6.7, 7.8 (CD) Sky Atlas 2000.0
chart 22
nu_sco
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging three 1/4 sec - f/4.9 - ISO 400 photos.
Jabbah; NexStar #3766; SAO 159765

Both are members of the wider double are double themselves. The fainter pair, CD, is 40.8" at P.A. 337° from AB. A-B are fairly similar B3 stars separated by 1.3" at P.A. 2°. C is a B8 and D 2.4" distant at P.A. 54°.
C and D are just being split. A and B are not although the combined star image is elongated north-south.
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging eight 1/15 sec - f/4.9 - ISO 400 photos. This image is at a non-standard magnification.

σ Coronae Borealis 16h 14.7m +33° 52´ Corona Borealis 5.6, 6.5 Sky Atlas 2000.0
chart 8
sigma_crb
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging six 1/4 sec - f/4.9 - ISO 400 photos. This image is at a non-standard magnification.
NexStar #3708; SAO 65165

A faint yellow G0 primary and fainter but, otherwise, nicely matched G1 companion separated by 6.9" at P.A. 237°

γ Herculis 16h 21.9m +19° 09´ Hercules 3.8 Sky Atlas 2000.0
chart 8, 15
gamma Herculis 2010-05-30 γ Herculis – 20 Herculis – SAO 102107 – NexStar # 3808

2010-05-30 White balance = 6000K (Cloudy)
Noise reduction = Off
negative projection (204×)
Created from nine 8 s - ISO 100 photos. I removed a dark frame from each photo, averaged them together, enhanced the contrast, rotated to north-up, cropped the photo and reduced its size 75%.

In this photo we can see the white, A9, primary and a faint 10.1 mag. B companion at 43.0" P.A. 227.0°. There's a third member too faint for this photo. I thought the B companion was easier to capture than I had assumed. This may be my imagination or an effect of B's color.



17 - 16 Draconis 16h 36.2m +52° 55´ Draco 17: 5.5, 6.4; 16: 5.4 Sky Atlas 2000.0
chart 3
17_dra
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging five 1/8 sec - f/4.9 - ISO 400 photos. This image is at a non-standard magnification.
NexStar #3867; SAO 30013

16 and 17 Draconis are a very evenly matched pair of pale blue B9 stars separated by 89.8" at P.A. 196°. The 17 Draconis companion, an white A1 star, is a challenge with only 3.0" separation at P.A. 107°.

56 Herculis 16h 55.0m +25° 44´ Hercules 6.1, 10.8 Sky Atlas 2000.0
chart 8
56_her
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging five 1/15 sec - f/4.9 - ISO 400 photos and enhancing the contrast. This image is at a non-standard magnification.
NexStar #8735; SAO 84692

This was a challenge. I couldn't see it because of poor transparency but did get this picture. The faint companion is separated by 18.1" at P.A. 91° from the G8 primary.

α Herculis 17h 14.6m +14° 23´ Hercules 3.5 Sky Atlas 2000.0
chart 15
alpha Herculis 2010-05-30 Rasalgethi – α Herculis – 20 Herculis – SAO 102680 & 102681 – NexStar # 3996 & 3997

2010-05-30 White balance = 6000K (Cloudy)
Noise reduction = Off
negative projection (204×)
Created from ten 0.5 s - ISO 100 photos. I removed a dark frame from each photo, averaged them together, enhanced the contrast, rotated to north-up, cropped the photo and reduced its size 75%.

This multiple is made particularly attractive because of the reddish color of the M5 primary and creamy color of the seconday. The companion, B, is a bit of a challenge being separated by only 4.8" at P.A. 104°. There are at least three other very faint members of this group.



ρ Herculis 17h 23.7m +37° 09´ Hercules 4.6, 5.4 Sky Atlas 2000.0
chart 8
rho_her
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging six 2 sec - f/4.9 - ISO 400 photos and the contrast modified to enhance the separation. This image is at a non-standard magnification.
NexStar #4040; SAO 66000

This pair has a pale blue primary and a white secondary separated by 4.1" at P.A. 319°.

ν Draconis 17h 32.2m +55° 11´ Draco 4.9, 4.9 Sky Atlas 2000.0
chart 3
nu_dra
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging five 1/2 sec - f/4.9 - ISO 400 photos.
Kuma; NexStar #4078 or 4081; SAO 30447 and 30450

This perfectly matched A4 and A6 pair is a wonderful and easy find. Separated by 63.3" at P.A. 311°, I had a zen moment looking at this pair.

μ Herculis 17h 46.5m +27° 43´ Hercules 3.4 Sky Atlas 2000.0
chart 8
mu Herculis 2010-05-30 μ Herculis – 86 Herculis – SAO 85397 – NexStar # 4130

2010-05-30 White balance = 6000K (Cloudy)
Noise reduction = Off
negative projection (204×)
Created from seven 8 s - ISO 100 photos. I removed a dark frame from each photo, averaged them together, enhanced the contrast, rotated to north-up, cropped the photo and reduced its size 75%.

In this photo we can see the yellowish, G5, primary and a faint 9.8 mag. B-C companion at 35.3" P.A. 249.0°. The B-C companion is actually two stars, as you might guess from their designation, but too close together for me to separate with my equipment. The primary is itself a double but also too close for me to separate in this photo, but not impossible on another try. The D companion would have been captured in this photo but is out of frame due north.



Barnard's Star 17h 58.0m +4° 15´ Ophiuchus 9.6 Sky Atlas 2000.0
chart 15
Barnards Star
EYEPIECE (MAGNIFICATION×)
PROCESSING 25.0 mm eyepiece (50.0×)
This is a combination of seven 16 s - f/2.8 - ISO 400 photos. I removed a flatfield from each, combined the individual photos and then strongly enhanced the contrast. Move the cursor over the photo to see the path of the star.
Runaway Star

Barnard's Star, at 5.96 l.y., is the second only to the Alpha Centauri triplet as the closest star to our solar system. It also has the honor of having the largest proper motion (apparent motion relative to the background stars) known: 10.29" per year. This means Barnard's Star will have moved more than the apparent diameter of the Moon in about 200 years. Quite recently, a flare (like a solar flare on our Sun) was observed so Barnard's Star is, now, also classified as a variable star. It is an faint M5 dwarf and a challenge for binoculars, but accessible to almost any telescope.

95 Herculis 18h 01.5m +21° 36´ Hercules 5.0, 5.2 Sky Atlas 2000.0
chart 8
95_her
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging three 1/2 sec - f/4.9 - ISO 400 photos.
NexStar #4190 or 4191; SAO 85647 and 85648

The primary is an A5 and the secondary is a G8 separated by 6.3" at P.A. 257°. According to Burnham, 95 Herculis has gained more than a little notoriety because of conflicting observations of the colors of this pair. Using the digital zoom, a greatly magnified image of the pair appears consistent with the known spectral types.

70 Ophiuchi 18h 05.5m +2° 30´ Ophiuchus 4.0, 6.0 Sky Atlas 2000.0
chart 15
70_oph
12.0 mm eyepiece, 3.0x telephoto (312.5×)
Created by averaging 10 images then the contrast was enhanced. This photo is not to scale with the others shown here.
NexStar #4203; SAO 123107

70 Ophiuchi should probably be called a cluster, not a multiple star, because is has 27+ companions. The brightest pair, A and B, are visible here separated by 4.6" at P.A. 141°. Both are orangish K type stars.

100 Herculis 18h 07.8m +26° 06´ Hercules 5.1, 5.8 Sky Atlas 2000.0
chart 8
100_her
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging five 1/4 sec - f/4.9 - ISO 400 photos. This image is at a non-standard magnification.
NexStar #4218; SAO 85752

This is a fainter, but perfectly matched pair of white stars separated by 14.2" at P.A. 183°.

α Lyrae 18h 36.9m +38° 47´ Lyra 0.0 Sky Atlas 2000.0
chart 8
alpha Lyrae 2010-05-30 Vega – α Lyrae – 3 Lyrae – SAO 67174 – NexStar # 4350

2010-05-30 White balance = 6000K (Cloudy)
Noise reduction = Off
negative projection (204×)
Created from nine 8 s - ISO 100 photos. I removed a dark frame from each photo, averaged them together, enhanced the contrast, rotated to north-up, cropped the photo and reduced its size 75%.

The apparent perfection of a 0.0 mag., A0 star makes Vega appealing. It also happens to be a neighbor lying just 25 l.y. away. I admit I was using it as a test subject and decided to process the photos "for grins". Low and behold, out popped two faint, unrelated field stars. What a pleasant surprise! But Vega is full of surprises. Astronomers now know that Vega has an infrared excess which implies it has a disk of dust like that of our own Sun. Perhaps there are planets in that disk too. What fun if one of our closer neighbors had a family of planets.



ε Lyrae 18h 44.3m +39° 40´ Lyra 5.0, 6.1 (AB)5.2, 5.5 (CD) Sky Atlas 2000.0
chart 8
epsilon_lyr
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging five 1/2 sec - f/4.9 - ISO 400 photos.
Double-double; NexStar #4374 or 4375 or 4376; SAO 67309 and 67310 and 67315

The famous "double-double" star is easily split using a small telescope with a separation of 208" at P.A. 172°. With a 3 inch (7.6 cm) or larger telescope and a steady sky, the fun realy begins when one sees that each member is, itself, a double. The northern pair, A-B or ε¹, are A4 and F1 stars separated by 2.4" at 350°. The southern pair, C-D or ε², are A8 and F0 stars separated by 2.4" at 81°. Both pair appear to have a slightly elongated shape in the photo above. By using the digital zoom on the camera, the "double-double" becomes more obvious in the image on the right.

ζ Lyrae 18h 44.8m +37° 36´ Lyra 4.4, 5.6 Sky Atlas 2000.0
chart 8
zeta Lyrae 2010-02-11 ζ1 Lyrae – 6 Lyrae – SAO 67321 – NexStar # 4377

2010-05-30 White balance = 6000K (Cloudy)
Noise reduction = Off
negative projection (204×)
Created from seven 8 s - ISO 100 photos. I removed a dark frame from each photo, averaged them together, enhanced the contrast, rotated to north-up, cropped the photo and reduced its size 75%.

A white A4 primary with a pale yellow F0 companion separated by 43.8" at P.A. 150°.



β Lyrae 18h 50.1m +33° 22´ Lyra 3.25 - 4.36V 12.9d Sky Atlas 2000.0
chart 8
beta Lyrae 2010-05-30 Sheliak – β Lyrae – 10 Lyrae – SAO 67451 – NexStar # 4408

2010-05-30 White balance = 6000K (Cloudy)
Noise reduction = Off
negative projection (204×)
Created from eight 8 s - ISO 100 photos. I removed a dark frame from each photo, averaged them together, enhanced the contrast, rotated to north-up, cropped the photo and reduced its size 75%.

In this photo we can see the blue-white, B7, primary and three of its apparent companions:
  (F) 10.6 mag. at 87.2" P.A. 19.0°.
  (B)   6.7 mag. at 46.0" P.A. 150.0°.
  (E) 10.1 mag. at 67.4" P.A. 317.0°.
None of these companions are gravitationally bound to the primary but Beta Lyrae is not alone. It is an eclipsing binary meaning it is a pair of stars aligned such that one star passes in front of, then behind the other from our view-point. The frequency and magnitude of change are such that Beta Lyrae is considered one of the easiest variables stars for amateurs to observe. If you'd like to give this a try, Sky & Telescope has a great Beta Lyrae web page with tips about observing this variable star, or Jim Kaler's Stars page on Sheliak for more background on this amazing object.



θ Serpentis 18h 56.2m +4° 12´ Serpens 4.6, 5.0 Sky Atlas 2000.0
chart 16
theta_ser
12.0 mm eyepiece, 1.0x telephoto (104.2×)
Created by averaging ten 1/2 sec - f/2.8 - ISO 400 photos.
NexStar #4441 and 4442; SAO 124068 and 124070

Another beautiful, evenly matched pair separated by 22.1" at P.A. 104°. Both are A5 type stars. A 7.9 magnitude third member at about the same distance but P.A. 58° is not visible in this photo.

Albireo 19h 30.7m +27° 58´ Cygnus 3.1, 5.1 Sky Atlas 2000.0
chart 8

Albireo

β Cygni – SAO 87301 and 87302 – NexStar #4597 or 4598

2009-08-30
White balance = 6000K (Cloudy)
Noise reduction = Off
negative project at 12.5 cm (325×)
Created from the seven best 1 s, ISO 800 photos.

Albireo is considered by many to be the finest double star for small telescopes. Its large separation, 34.6" at P.A. 55°, and the striking yellow and blue (or green) color contrast, produced by its K3 primary and B8 secondary, are sure to please.



17 Cygni 19h 46.4m +33° 44´ Cygnus 5.1, 9.2, 9.4 Sky Atlas 2000.0
chart 8
17_cyg
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging nine 1/2 sec - f/4.9 - ISO 400 photos and enhancing the contrast. This image is at a non-standard magnification.
NexStar #4657; SAO 68827

The magnitude difference makes 17 Draconis a bit of a challenge. The primary is a F5 star. The B companion is a K6 star separated by 26.3" at 67° and C by 110.4" at 125°.

Cygnus X-1 19h 58.4m +35° 12´ Cygnus 8.9 Sky Atlas 2000.0
chart 9
Cygnus X-1
25.0 mm eyepiece (50.0×)
This is a combination of ten 16 s - f/2.8 - ISO 400 photos. I enhanced the contrast slightly. Move the cursor over the photo to see the companion star HDE 226868 labelled.


HDE 226868, an 8.9 magnitude O9 star with a mass of approximately 20-30 Suns, has been the subject of intense scientific study for many decades. It is also a binary with an unseen companion, the two completing an orbit every 5.6 days. That orbital period plus the observed wobble of HDE 226868 implies the companion must have a mass of approximately 7-13 Suns. Other, observations indicated that the unseen companion is stripping gas from HDE 226868 and heating the gas to the point that it shines brightly in X-rays (thus the designation X-1). Put these facts together and you've made one of the strongest cases for the unseen object to be a "stellar mass" black hole.

ο¹ Cygni 20h 13.6m +46° 44´ Cygnus 3.8, 4.8, 7.0 Sky Atlas 2000.0
chart 9
omicron_cyg
12.0 mm eyepiece, 1.0x telephoto (104.2×)
Created by averaging six 1/2 sec - f/2.8 - ISO 400 photos.
NexStar #4772 and 4774; SAO 49332 and 49337

The 4.8 magnitude B companion to the northwest (upper-right) is at 300" and P.A. 324° and the 7.0 magnitude C companion is at 107" and P.A. 173°. These distances and angles match my measurements but the magnitudes of B and C look very similar in this photo. This is a good binocular object which is how I first saw it years ago.

There's a bit of confusion associated with this group. In some descriptions, A is also known as 31 Cygni and B as 30 Cygni. The B star is listed as D in the Washington Double Star Catalog (WDS). In the WDS, a close companion to A is given the B designation. Furthermore, B (as listed here) does not appear to be gravitationally bound to this system but, rather, forms an optical double with A, the formal term for a chance, close alignment of two stars.

α Capricorni 20h 18.1m -12° 33´ Capricornus 3.6, 4.2 Sky Atlas 2000.0
chart 16
alpha_cap
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging four 4 sec - f/4.9 - ISO 400 photos.
Al Giedi; NexStar #4790 and 4793; SAO 163422 and 163427

This is Al Giedi, "the goat". The primary is on the left and is called Secunda Giedi. At a distance of 292.0" at P.A. 381° is Prima Giedi. Both are multiples. Of all the companion stars, the 10.5 magnitude D companion of Secunda Giedi is evident at 152.1", P.A. 160°. The 9.6 magnitude C companion of Prima Giedi is at 46.5", P.A. 221°.

β Capricorni 20h 21.0m -14° 47´ Capricornus 3.1, 6.1, 8.8 Sky Atlas 2000.0
chart 16
beta_cap
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging five 1/2 sec - f/4.9 - ISO 400 photos and the contrast enhanced.
Dabih; NexStar #4806; SAO 163481

This is a wide system with a nice color contrast that's great for smaller telescopes. The primary is an F8 star. The B component is an A0 star separated by 207.0" at 267° while C is 225.1" away at 135°. I first looked at this group back in 1973. To remember that means it must have made an impression.

γ Delphini 20h 46.7m +16° 07´ Delphinus 4.3, 5.1 Sky Atlas 2000.0
chart 16
gamma_del
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging five 1/4 sec - f/4.9 - ISO 400 photos.
NexStar 4898 and 4899#; SAO 106475 and 106476

A is a pale yellow K1 star and B is a white F7 star 9.1" distant at P.A. 266°. I zoomed in to better show the colors.

M73 20h 59.0m -12° 38´ Aquarius 9.3 Sky Atlas 2000.0
chart 16

M73 2010-11-06

NGC 6994

2010-11-06
White balance = 6000K (Cloudy)
Noise reduction = Off
prime focus (81.3×)
Created from nine 15 s - ISO 1600 photos. I removed calibration frames from each photo and enhanced its contrast. I averaged all photos together, enhanced the contrast and removed a residual background. Finally, I rotated the image to north-up and cropped the image by 4.5.

Charles Messier created the most famous list of nuisances in astronomy if not history. Messier cataloged some of the brightest, most beautiful deep-sky objects so that he wouldn't confuse them with comets, his true passion (people didn't understand the true nature of the objects he cataloged so, while curiosities, scientifically they were a dead-end at the time). Many debate why some now-well-known objects were omitted, but M73 is an example for which folks wonder why it was included. M73 is an asterism (recognizable group of stars e.g. the Big Dipper) of four probably unrelated 10 - 12 magnitude stars. Messier's notes clearly describe this object so it is no mistake. Probably, through his telescope, this group of stars could be confused with a comet and it is near M72, now known to be a faint globular cluster which he cataloged at the same time, so onto the list it went.



61 Cygni 21h 06.9m +38° 45´ Cygnus 5.2, 6.0 Sky Atlas 2000.0
chart 9
61_cyg
12.0 mm eyepiece, 1.0x telephoto (104.2×)
Created by averaging five 1/2 sec - f/2.8 - ISO 400 photos.
The Flying Star; NexStar #4980; SAO 70919

A and B are separated by 30.9" at P.A. 151°. This is an attractive, matched orange pair to contrast with blue-white pairs like θ Serpentis or ν Draconis. There are several other, much fainter members to this system not visible in this photo.

61 Cygni has an impressive history. In 1792, Piazzi detetect an large proper motion (motion compared to other stars) of 5.22" per year. He was so amazed that Piazzi gave it the name "The Flying Star". This motion is large enough that I hope to photograph this pair over the years and actually see it move by comparing its position relative to the other stars in the pictures.

In 1838, F. Bessel made 61 Cygni the first star to have its distance directly measured. At 11.4 l.y., it is one of the closest stars to our Sun

Putting its motion, known distance, brightness and spectral information together implied that 61 Cygni is not part of the spiral disk of stars in our galaxy like the Sun, rather it is from the diffuse halo of stars which move in a gigantic sphere around the Milky Way. Being halo stars, 61 Cygni's members are very old and very poor in heavy elements.

μ Cephei 21h 43.5m +58° 47´ Cepheus 4.0 Sky Atlas 2000.0
chart 3
mu_cep
25.0 mm eyepiece, 1.0x telephoto (50.0×)
Created by averaging five 4 sec - f/2.8 - ISO 400 photos.
Garnet Star; NexStar #5107; SAO 33693

This is Herschel's famous "Garnet Star", so named because of its deep red color. And believe me, its color is striking by eye and telescope. Burnham calls this one of the reddest stars visible to the naked eye in the northern hemisphere. Like R Leporis, this is another star near the end of its life but μ Cephei is more massive. Thus, it appears fated to explode as a supernova and end as a neutron star.

ζ Aquarii 22h 28.8m +0° 01´ Aquarius 4.3, 4.5 Sky Atlas 2000.0
chart 17
zeta_aqr
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging five 1/60 sec - f/4.9 - ISO 400 photos and enhancing the contrast. This image is at a non-standard magnification.
NexStar #5263 and #5265; SAO 146107 and 146108

This is a pair of evenly matched F3 and F6 stars separated by only 1.5" at P.A. 19°. This photo doesn't really separate the two but does clearly appear elongated with the proper orientation.

δ Cephei 22h 29.2m +58° 25´ Cepheus 4.1, 6.3 Sky Atlas 2000.0
chart 3
delta_cep
25.0 mm eyepiece, 3.0x telephoto (150.0×)
Created by averaging five 1/4 sec - f/4.9 - ISO 400 photos.
NexStar #5267; SAO 34508

The F5 and the A0 companion are separated by 40.6" at 191°. δ Cephei is most famous as the namesake of cephied variables, a class of stars whose relatively quick and very regular changes in brightness are almost perfectly correlated to its brightness. This fortunate relationship has made them one of the "standard candles". Standard candles are objects whose characteristcs are sufficiently well determined that they can be used to gauge the distance to distant objects, like other galaxies. The primary of δ Cephei varies from about 3.6 to 4.2 magnitude with an apparent change in spectral type of F5 to G0 over 5.366341 days.

94 Aquarii 23h 19.1m -13° 28´ Aquarius 5.2, 7.0 Sky Atlas 2000.0
chart 17
94_aqr
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging ten 1/8 sec - f/4.9 - ISO 400 photos and enhancing the contrast. This image is at a non-standard magnification.
NexStar #5437; SAO 165625

This is a G5 primary with a companion at 12.4" and P.A. of 352°.

σ Cassiopeiae 23h 59.0m +55° 45´ Cassiopeia 5.0, 7.1 Sky Atlas 2000.0
chart 3
sigma_cas
25.0 mm eyepiece, 3.0x telephoto, 4.0x digital zoom (600.0×)
Created by averaging ten 1/8 sec - f/4.9 - ISO 400 photos and enhancing the contrast. This image is at a non-standard magnification.
NexStar #5556; SAO 35947

This is a B1 primary with a companion separated by only 3.2" at P.A. 327°.

Last modified: 2010-11-07