r .column-left-inner, column-left-outer { background: $(sidebar.bgl.color); } .column-right-inner, column-right-outer { background: $(sidebar.bgr.color); } .sidebar-right, .column-right-outer, #sidebar-right-1, .sidebar { background-color: #F5F7FA !important; padding: 15px; }
Total Solar Eclipse Begins in
Partial Lunar Eclipse Begins in

Translate / Traducir

Open Clusters in Cassiopeia

OBSERVING REPORT

OPEN CLUSTERS IN CASSIOPEIA

Date: September 15, 2012
Time: -
Binocular: 9x60
Observer: Leo Cavagnaro





























I started an observing project late that night so in the meantime I decided to observe some open clusters that lie in the beautiful constellation Cassiopeia, waiting for the moment of the beginning of my major observation.


Messier 52. Trumpler classification I,2,r. This 5 kly distant cluster, situated roughly 43 arc minutes south of the 5 magnitude star 4 Cassiopeiae, is visible through this kind of binocular. A few stars seem to be discerned when you see it from a dark sky site. It was discovered in 1774 by Charles Messier.   




NGC 7789. Trumpler classification II,1,r. Through this kind of small optical device, this open cluster looks like a round nebulous patch, appearing rather faint. However, it is an object for binoculars.
It was a discovery of Karoline Lucretia Herschel in 1783. It can be found aproximately 51 arc minutes south-southeast of the 4.5 magnitude star ρ Cassiopeiae.



NGC 129. Trumpler classification IV,2,p. Small stellar swarm close to the 6 magnitude star HD 2626, a double star according to the SIMBAD Database. Some of the brightest members can be glimpsed using averted vision. Friedrich Wilhelm Herschel discovered this object in 1788. NGC 129 lies at the middle of the imaginary line that connects the bright stars β (Caph) and γ Cassiopeiae.



NGC 225. Trumpler classification III,1,p,n. It looks like a faint hazy patch in the central part of constellation Cassiopeia, between the stars κ and γ Cassiopeiae. Known as the Sailboat Cluster, it is a loose and poor cluster. It was discovered in 1784 by Karoline Lucretia Herschel (sister of William) using a 4-inch reflector telescope.




NGC 457. Trumpler classification I,3,r. This cluster, discovered by Friedrich Wilhelm Herschel in 1787, usually known as the "ET" or Owl Cluster, is easy to find because you just need to aim your instrument to the naked eye star φ Cassiopeiae (visual magnitude 5). The cluster, that looks like an elongated nebulosity through a binocular, is detected immediately to the northwest of that star. In some sense, this cluster reminds me a short tail of a comet. Some stars can be glimpsed when using averted vision.


Stock 2. Trumpler classification III,1,m. Situated about 5° south-southeast of the 3.4 magnitude star ε Cassiopeiae (Segin), it is an interesting open cluster, big, and elongated in the same orientation that the double cluster of Perseus (W-E). It is a swarm of stars with similar brightness that is easily discerned through a binocular. Stock 2 lies within a triangle formed by three stars (visual magnitudes between 6.5 and 7) that are brighter than the cluster members.

NGC 7635, The Bubble Nebula

OBSERVING REPORT

NGC 7635 - THE BUBBLE NEBULA in Cassiopeia

Date: August 15, 2012
Time: 07:51 UT   LOCAL TIME (UT-7hs.)
Telescope: 24" (61cm.) f/4
Observer: Leo Cavagnaro


Click on the image to enlarge
Finder chart 

How to find it,
About 1° 10' to the south-southwest of the star 4 Cassiopeiae (visual magnitude 5).
 

Stars in chart up to visual magnitude 6.0





NGC 7635 (Bubble Nebula).
This nebula is formed by gas being compressed by a strong stellar wind from “Wolf-Rayet” massive star BD+602522. NGC 7635, discovered by Friedrich Wilhelm Herschel in 1787, lies not too far from the well-known cluster, for the northern stargazers, Messier 52 (about 35 arc minutes to the southwest), in the constellation Cassiopeia. A pattern of five stars (linked with gray lines in the DSS image to the right), with visual magnitudes between 8.7 (the brighter one) and 10 (the fainter one), helps to identify the nebula in the field of view of the telescope. The nebula surrounds one of the stars of the pattern, the 8.7 visual magnitude BD +602522 that lies to the side within the nebulosity. I have indicated the star with the white arrow in the lower DSS image.

At 59x through a 24-inch telescope and an OIII filter, the nebula looks smooth in brightness. The outer parts look fainter than the central region near the star. 
At higher magnification (122x) and using a nebular filter (OIII), the structure of NGC 6735 is very interesting, showing bright nebulosity surrounding the star with a small region even brighter immediately to the west of the star BD +602522. Fainter nebulosity is visible, elongated northwest-southeast.


Close-up view of NGC 7635 and its brighter region. 
North is up.


The Crescent Nebula

OBSERVING REPORT

NGC 6888 - THE CRESCENT NEBULA in Cygnus

Date: August 15, 2012
Time: -
Telescope: 24" (61cm.) f/4
Observer: Leo Cavagnaro


Click on the image to enlarge
Finder Chart

How to find it,

About 2°45to the southwest of the 2.2 visual magnitude star Sadr (γ Cygni).

Stars in map up to visual magnitude 6.



NGC 6888 is an easy object to see through a 24" telescope working at low magnification (60x) and an OIII filter. NGC 6888 is associated with WR 136 (HD 192163), considered to be a member of the Cygnus OB1 association. The observations of 62 galactic WR stars in the northern sky show that about half are associated with nebular emission (Miller and Chu 1993), some of which are ring nebulae. Johnson and Hogg (1965) were the first to propose that these ring nebulae were formed by stellar wind interaction with the local interstellar medium.

At the mentioned magnification, this nebula looks clearly elongated with an oval shape and the rim showing higher brightness. The small area indicated by the arrow in the DSS image (left) is the brightest part of this object. The northeast rim looks brighter and narrower than the opposite one, which looks wider and fainter. The inner part of this object is less prominent in nebulosity, appearing fainter.