Re: (IAAC) OBJECT: M13 Hercules Cluster (Globular) INST: 18" F/4.2 Newt.

More fantastic CCD images!  I really loved the shot of M81.
I've never noticed the little propellor in M13's core or the other two dark lanes
that you mentioned and will make it a point to do so the next time I view this
Dave Mitsky
Todd Gross wrote:
> Observer:  Todd Gross
> Your skill:  Intermediate
> Date and UT of observation: 2/7/99 10:00GMT
> Location & latitude: 22 mi. West of Boston, Ma. 42.3N
> Site classification: Suburban
> Limiting magnitude (visual): 4.5(estimated) zenith
> Seeing (1 to 10 - worst-best): about 3
> Moon up (phase?): Yes, Gibbous
> Weather: Mostly Clear
> Instrument: 18" Stabilite Newt f/4.2 1925mm fl
> Magnifications: 214X, binoviewer
> Filters used: none
> Object: M13
> Constellation: Hercules
> Object data: Globular Cluster
> Size(s):
> Position:
> Magnitude: 5.8
> Personal 'Rating' (at this aperture and sky condition): A+
> After developing a CCD photograph (http://www.weatherman.com/edf.htm)
> of M13, I wanted to try again with the 18" scope to see how much of
> the detail I could ascertain visually. A more overall description of M13
> can be found with my previous 16" scope in the NETASTROCATALOG.
> I am happy to report that quite a bit of the detail in the CCD photo
> is there at the eyepiece too. The magnificent cluster breaks to individuals
> down to the center of the core with detail seen. The outer arms (strings
> of stars) branching out from M13 are not symettrical. There are two
> particular strings that come out, and flatten out on the NE side that always
> give me a frame of reference. Within the core is a noticeable sideways
> "Y" dark lane on that NE side. Being that each leg of the Y is about the same
> length, it is nick-named the "propeller". Also easily discernible is the
> "little propeller", or a small group of stars just below the core (assuming
> NE is "up") The bright group of stars near the center of the cluster is
> clearly
> shaped as a small "X". The bottom right hand part of the X is dimmest.
> I also searched for more dark lanes visible in the ccd photo. One was found
> on the right hand (north) side coming off the core, as a straight-line
> gap following along a straight line of stars. Another thin dark lane in the
> vicinity of the "Y" was not discerned, probably because of poor seeing.
> thanks!
> -Todd
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