Observing Report – 6/02/2001

Frank N. Bash Visitors Center (Star Party)

Frank N. Bash Visitor Center [credit: The University of Texas at Austin/McDonald Observatory]

Observing session at the McDonald Observatory.


Telescope:  Sky Designs 24″ Dob f/4
Location:  McDonald Observatory, Ft. Davis, Texas, USA
Time:  11 pm – 1 am
Seeing:  8
Sky Transparency:  5
Limiting Magnitude:  ~ 3.5
Lunar Phase:  Waxing Gibbous


Just a few days from a Full Moon, I got the unique opportunity to use a 24″ Dob at the McDonald Observatory’s Visitor Center after the public had left.  This was possible because I went to McDonald with the University of Texas’ Astronomy Student’s Association.  The sky clouded over around 1 a.m. leaving us with little of the galactic center high enough to observe, but we did get the chance to view some nice late Spring/early Summer objects.


  • M 13 – On the previous night I had a chance to view Omega Centauri for the first time through an 8″ Dob.  While the view was pleasant, it wasn’t exactly breathtaking.  The same can be said of M13 through the 24″.  Although the cluster was resolved with no background glow, not many stars were visible.  I would attribute this to the light pollution being put out by the Moon.  In the future I hope to have another crack at this cluster under better seeing conditions.
  • M 57 – Well, now I can see why planetary nebulae are so interesting in a large Dob.  The Ring Nebula usually looks rather uniformly dim and gray through my small apo scope, but with the 24″ Dob it was bright and greenish [even under a nearly Full Moon].  The ring was much brighter than the center, and the central star was easily seen.
  • Mars – With the collimation a bit off, I could still see excellent surface detail through a not so clean eyepiece.  The polar cap was visible as were dark features across the orangish sphere; in fact, the view looked like a miniature HST picture. Very impressive!
  • Beta Cygni – aka Albireo.  Wow!  It’s always difficult to make out strongly the color of the bluish component of this fine double with a small scope but the 24″ Dob showed it unmistakingly.  Both the yellow primary and blue secondary were outrageously bright and the best I’ve seen to date.
  • Zeta Ursae Majoris – Mizar and Alcor are easily recognizable as the close “double” star in the handle of the Big Dipper [you actually see three stars through a telescope].  I’m used to seeing this multiple star system as small, bright points of light in my Takahashi refractors – not so in the big Dob!  All three stars look like small white high-beams pointed directly at you.  I was absolutely floored by the view and am now determined to get the largest Dob I can handle.

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