Archive for October 29, 2018

NGC 147 and NGC 185 – Galaxies in Cassiopeia – November 2018 Observer’s Challenge Report #117

October 29, 2018

 NOVEMBER 2018 OBSERVERS CHALLENGE – NGC-147  

Calculating the surface brightness magnitudes:  

Information from Observing handbook and Catalog of Deep-Sky Objects” by Christian B. Luginbulh and Brian A. Skiff :  

“The surface brightness magnitudes (sfc. br.), also from the * RC2, represent the brightness (in V or B, depending on the color of the integrated magnitude ) of a square arc minute patch averaged over the galaxy within the dimensions given for each.  Since this value is an average, the central parts of the galaxy will typically have higher surface brightness and the outer parts lower.”

For complete information concerning (sfc. br.) refer to pages 10-11 Observing Handbook and Catalog of Deep-Sky Objects.”   Luginbuhl and Skiff. 

* RC2 =  “….nearly all data on galaxies are from the Second Reference Catalogue of Bright Galaxies (RC2) by de Vaucouleurs, de Vaucouleurs and Corwin, and the Southern Galaxy Catalog (SGC) by Corwin, de Vancouleurs, and de Vancouleurs.” 

Images provided by Mario Motta from Massachusetts using a 32-inch reflector. 

Photographic information:  NGC  147 was a total of 70 minutes, taken August 10, 2015 with my 32 inch, SBIG STL camera 1001E.  NGC 185 was taken August 15, 2015 total of 50 minutes (must have had a bad frame and dropped, I almost always do at least 60 minutes)   Mario Motta

NGC 147:  Visual magnitude 9.5,   (sfc. br.) 14.5  

2169290_2_NGC147

NGC 185:  Visual magnitude 9.2,   (sfc. br.) magnitude 14.3 

2169290_3_NGC185

Observing notes and pencil sketches by Sue French from New York:

254/1494mm Newtonian

43×: By sweeping westward from Omicron Cassiopeiae, NGC 185 is immediately visible ensconced in a isosceles triangle of three 8th- to 10th-magnitude stars, the brightest one golden.

68×: The sketch was done at this magnification, where NGC 185 and NGC 147 just fit together in the 72 arcminute field of view.  NGC 185 has a small core that grows gently brighter toward the center. NGC 147 is more slender than its companion and very faint.  There’s a dim star superimposed on NGC 147, barely west of the galaxy’s center. Both galaxies lean roughly northeast by east, with plump NGC 185 have a slightly greater position angle. Most of the stars visible near the galaxies were sketched, but far too many showed in the richly populated Milky Way for me sketch all the field stars.   Sue French 

Pencil sketch with inverted colors:  SF 

image001

image002

 

Observing notes and pencil sketches by Roger Ivester

NGC 147, with a 10-inch reflector is very difficult at 57x, and best observed at magnifications of 114x and 160x from my 5.0 NELM backyard.  The galaxy is very faint and difficult, due to the extremely low surface brightness.  Elongated NE-SW, without concentration, with a faint star located almost in the halo to the north.  On nights of fair transparency, I’ve been unable to see this galaxy.  A dark sky is essential to successfully observe this object.  

The first time I observed this galaxy was in on October 12th 1993.  My note at that time:  10-inch reflector @ 57x, faint, and difficult with very low surface brightness.  At 95x, still dim, but noted an elongation of NE-SW, low surface brightness, and mostly featureless.  When first observing both NGC 147 and NGC 185 almost twenty five years ago, I used the photo’s in Burnham’s Celestial Handbook to verify my find.   

NGC 185, using a 10-inch reflector at 114x, shows this galaxy as large, mostly round and on nights of excellent transparency, a subtle center brightness.  Far easier and brighter than NGC 147.   Roger Ivester  

 

Pencil sketches:  

NGC 147
Rogers NGC-0147 Inverted
NGC 185
Rogers NGC-0185 Inverted