Deep-Sky Obje…

Aside

 Deep-Sky Objects Contained in the book 

In Starland with a Three-Inch Telescope

By: William Tyler Olcott

Published in 1909

 There have been several people who have compiled a list of the double stars that Olcott included in the book “In Starland with a Three-inch Telescope.” This is a good list to work your way through for those interested in double stars. Then someone on Yahoo’s 60mm telescope club web page recently suggested observing the list of deep-sky objects in this book as an observation list, but I have never seen these objects put into a list, so I thought I would give it a try.

 When I started going through my copy of this book, I became aware that the numbers used for these objects were not the familiar NGC numbers. My problem was trying to figure out what numbering system Olcott used for the clusters and nebula he included. Remember that in 1900 everything in the sky was either a nebula or a cluster, there were no galaxies yet. I had always assumed that these numbers were NGC numbers. It turns out that they are General Catalog (GC) numbers, the predecessor of the New General Catalog (NGC). I now have it figured out and have converted these GC numbers to their equivalent NGC numbers for a possible observing project.

 The list turns out to be a strange mix of objects. There are only 41 Messier objects included and there are 44 NGC objects included too for a total of 85 nebula and clusters in Olcott’s list. I started to wonder why he included the objects he did and left out some really bright objects near other objects he included. For example he included M80 in Scorpius, a small dim globular to me, and left out M4, which is resolvable, and he also missed the bright clusters M6 and M7 which from a dark sky are naked eye objects. Another example, he includes Tuttle’s variable nebula, NGC 6643 (mag. 11.5) in Draco and left out the bright Cat’s Eye Nebula, NGC 6543. He includes NGC 2903 & 2905 in Leo but nothing of M65, M66 or M95, M96 and M105. If I recall correctly, Olcott entered into astronomy only four years before he wrote In Starland with a Three-inch Telescope. So I think this has more to do with information not being readily available in the early 1900’s and the fact that he had only been observing for four years when he wrote the book. He may have included all the objects he had seen at that time and nothing else. That explains for me the limited and spotty coverage of this list.

The first column in this list is the now familiar NGC or IC number for each object followed by the General Catalog number and the Messier number where applicable. I have listed next what we know each object to be today. For Olcott, each object was listed as a nebula, cluster and a few as globular clusters. The boundaries of the Constellations were not set when Olcott prepared his list of objects so I have shown the constellation each object is located in today, which is not always the same constelation that they are shown to be located in in Olcott’s book. This is followed by the integrated magnitude for each object and it’s listed size. Last I have shown the common name for each of the objects that have them.

I hope you enjoy observing this list as much as I did preparing it.

NGC No. GC No. M Type Const. Mag. Size

129     63    –   OC  Cas  6.5  21

224   116  31  Gx   And  3.6  192’x62′ The Andromeda Galaxy

225   120   –    OC  Cas  7.0  12′ The letter “w” cluster

253   138   –    Gx   Scl   7.8   27’x7′ The Sculptor Galaxy

457   256   –   OC  Cas  6.4  13′ The Airplane/Owl/ET Cluster

524    307   –  Gx   Psc  10.5  3′

598    352  33  Gx  Tri    5.8  71’x42′ Pinwheel or Triangulum Galaxy

663    392   –   OC   Cas  7.1  16′

752    457   –   OC   And  5.7  50′

869    512   –   OC   Per  5.3  29′ Part of Double Cluster

884    521   –   OC   Per  6.1  29′ Part of Double Cluster

1039  584  34  OC  Per  5.2  35′

1245  658   –    OC  Per  8.4  10′

1342  717   –    OC  Per  6.7  14′

1513  809   –    OC  Per  8.4  9′

1528  820   –    OC  Per  6.4  23′

1535  826   –    PN  Eri   9.6  48”x42” Cleopatra’s Eye

1545  831   –   OC  Per  6.2  18′

1662  905   –   OC  Ori   6.4  20′

1778  996   –   OC  Aur   7.7   6′

1817  1030  – OC  Tau  7.7  16′

1857  1067  – OC  Aur   7.0   5′

1893  1101  –  OC  Aur  7.5  11′ Associated with Nebula

1904  1112  79  GC  Lep  7.7  9′

1912  1119  38  OC  Aur  6.4  21′

1952  1157   1  SNR Tau 8.4  6’x4′ Crab Nebula

1960  1166  36  OC  Aur  6.0  12′

1976  1179  42  BN  Ori   4.0  90’x60′ The Great Nebula in Orion

1981  1184   –   OC  Ori    4.2   25′

2099  1295  37  OC  Aur   5.6  23′

2168  1360  35  OC  Gem  5.1  28′

2169  1361   –   OC  Ori   5.9   6′ The “37” Cluster

2194  1383   –   OC  Ori  8.5  10′

2244  1424   –   OC  Mon  4.8  24′ Cluster in the Rosette Nebula 

2281  1451   –   OC  Aur  5.4  14′

 2287  1454  41  OC  CMa  4.5  38′ The Little Beehive

 2318  1479   –   OC? CMa    –     –    Sparse group, NOT a cluster

 2359  1511   –   BN  CMa    –  10’x5′ Thor’s Helmet or Duck Nebula

2420  1549   –   OC  Gem  8.3  10′

 2548  1637  48  OC  Hyd  5.8  54′

 2632  1681  44  OC  Cnc  3.1  95′ The Praesepe or Beehive Cluster

 2682  1712  67  OC  Cnc  6.9  29′

 2903  1861   –   Gx   Leo  9.0  12’x6′

 2905  1863   –   Gx   Leo   –      –  The northeast arm of galaxy 2903

 3031  1949  81  Gx  UMa  7.3  27’x14′ Bode’s Nebula

3034  1950  82   Gx  UMa  8.9  11’x5′ Cigar Galaxy

 3166  2038   –    Gx  Sex  10.4   5’x2′

 3169  2041   –    Gx   Sex  10.7  4’x3′

 3242  2102   –    PN  Hya   7.7   45”x36” Ghost of Jupiter

 3587  2343  97  PN  UMa  9.9  3.4′ Owl Nebula

 3800  2488   –   Gx  Leo   12.9  2’x0.6′

 4361  2917   –   PN  Crv   10.9   2′

 4762  3278   –   Gx   Vir    10.0   9’x2′

 5194  3572  51  Gx  CVn  8.5  11’x8′ Whirlpool Galaxy

 5272  3636   3   GC  CVn  6.3  18′

 5904  4083   5   GC  Ser   5.7   23′

 6093  4173  80  GC  Sco   7.3   9′

 6171  4211 107 GC  Oph  7.8  10′

 6205  4230  13  GC   Her  5.8   17′ The Great Hercules Cluster

 6254  4256  10  GC   Oph  6.6  15′

 6273  4264  19  GC   Oph  6.8  14′

 6284  4268    –   GC   Oph  8.9   6′

 6287  4269    –   GC   Oph  9.3   5′

 6293  4270    –   GC   Oph  8.3   8′

 6341  4294  92  GC   Her   6.5  14′

 6402  4315  14  GC  Oph   7.6  12′

 6494  4346  23  OC  Sgr   5.5   30′

 6514  4355  20  BN  Sgr   6.3   20′ The Trifid Nebula

 6523  4361   8   BN  Sgr   5.0   45’x30′ The Lagoon Nebula

 6603  4397   –    OC  Sgr  11.1   5′ OC in M24, small Sag. Star Cloud

 6613  4401  18   OC  Sgr   6.9   9′

 6618  4403  17   BN  Sgr   6.0   20’x15′ The Swan, Checkmark or Omega

 6643  4415    –   Gx   Dra   11.5   4’x2′

 6656  4424   22  GC  Sgr   5.2  24′

 6709  4440    –    OC  Aql   6.7  13′

 6720  4447  57   PN   Lyr  8.8   86”x62” The Ring Nebula

 6838  4520  71   GC   Sge  8.4   7′

 6853  4532  27   PN   Vul   7.4    8’x6′ The Dumbbell or Apple Core Neb.

 7009  4628   –    PN  Aqr   8.0    44”x23” The Saturn Nebula

 7078  4670  15  GC  Peg  6.3    12′

 7089  4678    2   GC  Aqr   6.6    13′

 7092  4681  39   OC  Cyg  4.6    31′

 7099  4687  30   OC  Cap   6.9   11′

 7789  5031   –     OC  Cas   6.7   25′

 IC4725   –     25   OC  Sgr      –     32′

 

 

 

M104, Humidity and Observing the Deep-Sky

Although I have known this for many years, It really hit home this spring when we had some really dry air over us. A few weeks ago we had a rather dry air mass pass over us and I could see stars that I don’t usually get to see. I know that air with humidity in the 30% to 40% range is not very dry for some places but here in North Carolina, where the normal summer time readings are in the 70% to 80% range, it was very dry for us. It was wonderful observing from home with such low humidity readings where I could easily see the Messier galaxies and many NGC galaxies.

In contrast to the low humidity, this past Monday I was out observing with much higher humidity readings. With the humidity at a still low 63%, I tried to find many of the galaxies that I had observed only a week before, only to find that I could just detect the presence of those galaxies and no longer really see them. This was very disappointing, knowing that the humidity was only going up in the months ahead. 

What causes this to happen? Summers in the southeastern United States tend to be very humid and that humidity holds pollen and dust particles in the air. These particles and the moisture in the air tend to scatter the light pollution, that is so common today, making the sky appear brighter. The end result is that the summer sky is much brighter than in the winter months. This brightening of the sky makes it almost impossible to see faint objects or the fainter outer regions of galaxies. Only the brightest portions of the inner areas of galaxies may be seen. For example, I observed M104 in Virgo. This galaxy has a listed size of 9’x4′ but what I could see was only approximately 3’x1′ in size. Obviously I was only seeing the brighter inner core region of the galaxy. Here is a sketch of this portion of M104 as seen Monday night. I was suprised to see the dust lane at magnification of 200x.

NGC1662 & 2169 in Orion

Orion is the home of two of my favorite wintertime open clusters. With Orion setting in the western sky early in the evening now, I have been scrambling to see these clusters for the last time this winter. The first is NGC 1662, The Klingon Battle Cruiser cluster. If you, like me, were a fan of the original Star Trek TV series, then you remember how the Klingon Battle Cruiser looked. Sue French in her February 2005 Deep-Sky Wonders column has a picture of the battle cruiser superimposed on this sparse cluster, and the stars definitely look like the running lights on the cruiser. I have never seen this cluster as anything else since.  Even in my light polluted skies, I see in town a good dozen stars with my 4-inch TV102 refractor. Check it out if you haven’t yet.

The second cluster is the Thirty-Seven Cluster, NGC 2169. This is a wonderful little cluster, whose stars are divided into two groups of stars. From home in my light polluted skies, using a C-6 or a 6-inch SCT, I see 11 stars in the southeastern group and 7 stars in the northwestern group. All of these stars can be seen within an area about 6 arc minutes in diameter. These stars look like a mirror reversed 37 in my scope at a magnification of 150x. Here is a sketch I prepared last week of this cluster. 

Image

Two more wonderful Asterisms?

Since I brought up asterisms, I thought I would share two of my favorite summer asterisms and what I found out about them.

If you are like me, every spring you enjoy that star hop from Corvus to M104, the Sombrero Galaxy. Who can forget that line of four stars from gamma Corvus (Gienah) that ends with three stars, which look like an arrowhead pointing at the little asterism known as the Stargate, STF 1659. That’s right, I only recently learned that this little asterism is actually a multiple star system that is contained in the Washington Double Star catalog. I will bet that you, like me, thought that this grouping of stars got its name from the TV series by the same name but it didn’t. It was given this name from the Buck Rogers TV series back in 1979.

This multiple star, STF 1659, is made up of two triangles of stars; one nested inside the other. These six stars range in magnitude from 6.6 to 10.8. It is interesting that the Virgo diamond, described below, is about the size of the little triangle nested in the larger triangle in the DSS image below.

This is my sketch of this wonderful asterism or multiple star system.

Continuing on with the line of stars and the Stargate asterism will take you shortly to another asterism that I have found out is also a multiple star system, STF 1664, known as the Jaws. Although this is part of a much larger asterism of a shark, the gaping mouth of the shark is known as the Jaws and looks almost like a small Sagitta pointing straight at the Sombrero Galaxy, M104. These stars range in magnitude from 8.5 to 12.3 and you can see how close to M104 they are in this DSS photo.

I can see both of these multiple star systems from home in my 10×50 binoculars as a fuzzy little knot of stars. If you are not careful you might think the Jaws is M104, but look carefully, M104 is fainter but visible in the binoculars too.

The Stargate, STF 1659, is located at R.A. 12h35m44s, Dec. -12d01m30s and The Jaws, STF 1664 is located at R.A. 12h38m20s, Dec. -11d31m01s

The Virgo Diamond, A Challenging Asterism

Who would have thought it? In the middle of galaxy season, there is a seldom observed small asterism that has been called “a stellar diamond in Virgo”. Jaakko Saloranta, an observer from Finland states that “what makes this asterism curious and stand out is the diamond or square-shape and its tiny size (50″).” The separation between the stars is – on average – only 30″.  Good seeing conditions and higher magnification is required to resolve the four main components into individual stars. Seeing the 5th star on a less than average night, may require a  telescope with a larger aperture than the typical backyard telescope.

As reported in the May 1993 issue of Sky and Telescope Magazine, page 110, Noah Brosch of the Tel Aviv University, Israel, discusses his investigation of a newly discovered asterism in the December 1991 Monthly Notices of the Royal Astronomical Society. In summary he states that this is a system of five stars arranged in the form of a diamond. The stars have similar spectral types and radial velocities, indicating that the system is probably an evaporating small cluster in the Galactic halo.

Roger Ivester, an observer from North Carolina, said that on his first observation in his 10-inch Newtonian that he was surprised by how small the diamond appeared. Sue French, an observer from New York, states that with her 4-inch (105mm/610mm) the northern most star was easy but the other three are very faint at 122x. With her 10-inch Newtonian she could see all five stars at 213x. This year at the Winter Star Party, she could see all five stars with her 5-inch (130mm/819mm APO) at 164x. Several other people have seen all five stars with larger instruments.

Have I got you interested yet? This is a great challenge object that is a very nice break in the middle of galaxy season. With small telescopes this asterism will require dark skies with good seeing and good transparency. To help you I have prepared a sketch of this asterism from available information. It is located between Gamma (Porrima) and Eta (Zaniah) Virginis at R.A. = 12h 32.8m and Dec. = -00d 42m. The brightest star in the group is the 10.7 magnitude star TYC 4948-53-1.

and below is a photograph of the Diamond by Don Olive. This is , of course, not to be taken for the Great Diamond of Virgo. The four stars that form the Diamond of Virgo are Cor Caroli (in Canes Venatici), Denebola (in Leo), Spica (in Virgo), and Arcturus (in Bootes).

Observing NGC 3115, A galaxy in Sextans

I looked at this galaxy a couple of weeks ago with the 5-inch ETX125PE and was surprised to have seen it. Saturday night I looked at this galaxy once again with my 4-inch TV102 refractor and was once again surprised by the viewing of this galaxy. Yes it is a very bright galaxy but I live in what is considered to be a white zone on the light pollution map. The sky was clear and transparent but I could only see naked eye stars down to about magnitude 4.1 so seeing this galaxy is attributed to the transparent skies of winter. A view like this could not be acheved in the summer time with it’s haze and humidity. The central core area is much brighter and can be seen with direct vision as a fuzzy spot while the outer regions can only be seen with averted vision tapering to nothing. I estimated the size of the galaxy to be 5 to 6 minutes long by approximately 1 minute wide in the center.

Image .

A Short Night of Observing

Last night, still recovering from the flu, I sat up my ETX 125 PE telescope for a short nights viewing. I just could not stand another clear night and not getting a scope out, so over a two hour period I observed 16 objects and made one sketch. As you know my home is located in town in a heavely lighted polluted area that is in a white zone on the light pollution map. Therefore I pretty much selected objects that are fairly bright but I did attempt to observe some not so bright objects too.

The most surprising view of the night was the open cluster NGC 2244 and the associated Rosette Nebula NGC 2237. Using a 24mm eyepiece for a magnification of 79x with a true field-of-view of 52 arc minutes or 0.87 degrees, the open cluster is obviously located in the hole of a very faint nebula that is almost twice the size of my field-of-view east to west and about one and a half times the size of the field-of-view in a north-south direction. With a OIII filter the nebula was easier to see but still very faint. I would have never dreamed that this object would be visible with all the light pollution. I only regret that I did not use a telescope with a larger field-of-view.

For my sketch I chose the March object for the Las Vegas Astronomy Clubs Observers Challenge, NGC 2362, the Tau Canis Major cluster. This cluster use to be called the Mexican Jumping Bean Cluster and is often described as a jewel surrounded by diamond dust. This cluster is known as the Mexican Jumping Bean Cluster due to an interesting effect that occurs if the telescope is tapped. The clusters fainter stars will appear to stop moving while the bright central star Tau CMa continues to move. This happens due to a phenomenon known as persistence of vision and is a very neat effect to watch. Here is my sketch of this cluster;

There were two double stars that I also looked at last night, I really enjoy colorful doubles. The first was Almaak, gamma Andromeda. which is a beautiful lemon yellow with a light blue companion separated by 9.8 arc seconds. This double star is almost an Albireo look a like. The second is actually called the Winter Albireo, h3945 in Canis Major, which is located just north of NGC 2362. This colorful double is a golden orange with a blue companion separated by 26 arc seconds. Although I do not think it is as pretty as Albireo, the colors are very striking and well worth a look.

Another surprise for the night was viewing the galaxy NGC 3115 with the  ETX 125 using a 13mm eyepiece for a magnification of 146x and a true field-of-view of 34 arc minutes. With all the light pollution the galaxy appeared to be only half its size, approximately 4 to 5 minutes long by 1 minute wide and oriented in a north-east to south-west position. Even though this is a bright galaxy it is unusual to be able to see galaxies in such light pollution.