Skip to Navigation | Skip to Content

Previous image Up to Astr111 Index Next image ASTR 110 Photography Projects, Fall 2015

Spiral Galaxy IC 365 & Spiral Galaxy NGC 891
Alex Hinga & Nick Genzink

Helix Nebula Orion Nebula
IC 365 - Alex Hinga

NGC 891- Nick Genzink

These are photos of spiral galaxies IC 365 and NGC 891. Galaxies are large groups of stars that are held together by gravity and orbit around a common center. Spiral galaxies get their name because of their shape. They are characterized as white disks with a yellowish bulge in the center and spiral arms that are usually blue in color. Star forming regions are located within the spiral arms. These regions usually appear red or pink in color. Spiral galaxies are unique because unlike eliptical and irregular galaxies, they are the only type of galaxy with constant star formation.

IC 365 is a spiral galaxy that was discovered in 1894 by the French astronomer Stephane Javelle. Generally spiral galaxies contain a lot of blue light because of the heat given off during star production. However, this image appears mostly in yellow and red wavelengths. Even though there is no blue light, this photo may be a more accurate representation as to how the galaxy would appear to the human eye. The blue wavelength can be especially difficult to pick up. Because of its size, distance, and the quality of our telescope, the wavelength is almost impossible to detect in this image. However, an interesting feature was detected in this picture. The orange smudge appearing in the upper left corner is actually another galaxy. The galaxy is too small to have been given a formal name. However it has been cateloged under the name 2MASX J04083779+6950160. Not much is known about this galaxy but it was an unexpected find in this image.

<Description of NGC 891 missing>

Both IC 365 and NGC 891 are spiral galaxies. In both of these your are able to see the central bulge. The central bulge also appears yellow in both images. This is to be expected because in spiral galaxies, the central bulge is an area where no star formation occurs. The yellow color indicates a cooler temperature which is to be expected because no star formation is occuring. Some aspects of the spiral arms, where star formation occurs is also visible in both images.

While these images both depict spiral galaxies, there are many differences in their appearance. One major difference is the angle at which the image was taken. An over head view of IC 365 is visible where as a side view of NGC 891 is visible.This means that in the image of NGC 891 you are able to see how the galaxy is relatively flat, except for the central bulge. The size of the objects are also different because NCG 891 is larger, closer, and brighter than IC 365. In the image of NGC 891 a lot of blue light is visible but that same light is not visible in the image of IC 365. Because of this, it appears as though NGC 891 is hotter than IC 365. However, it is difficult to be sure of the exact temperature of either galaxy because the blue filter did not pick up very much light in the image for IC 365. Another difference is that the spiral arms appear to be more tight in galaxy NGC 891. In galaxy NGC 891, you are also able to see some areas of star formation within the spiral arms. These areas are the redish specks within the blue of the spiral arms. No areas of star formation are visible in the image of IC 365.

References:

Bennet, J., Donahue, M., Scneider, N., & Voit, M. (2015). The Cosmic Perspective Fundamentals (Second ed.). N.p.: Pearson. (Original work published 2010)

Seligmen, C. (2014, February 21). IC Objects: IC 350-399. In CSeligmen. Retrieved November 19, 2015, from http://cseligman.com/text/atlas/ic3a.htm#ic365

2MASX J04083779+6950160. (n.d.). In Sinbad. Retrieved November 19, 2015, from http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%40281134&Name=2MASX%20J04083779%2b6950160&submit=submit

Object IC 365 NGC 891
Right Ascension (J2000) 04:07:46  
Declination (J2000) 69:48:43  
Filters used B (Blue), C (Clear), R (Red), V (Green)  
Exposure time per filter B and C (300s x 2); V and R (150s)  
Image dimension 377x243 pixels; 8.17x5.27 arcminutes  
Date/time observed September 28, 2015, 12:05 UT  

 

Secondary

Secondary content.

Sidebar

Side content.