The Observing Notes
  Descriptive notes on these observations should be interpreted in terms of the
seeing and transparency conditions under which they were made.  Best conditions
are sought, but few observations were made under ideal viewing conditions.
Therefore, descriptions do not correspond to all details that can be seen with
the equipment used. All notes are made at the telescope, without use of
observing guides. Acquisitions are verified using the Observing Handbook and
Catalogue of Deep Sky Objects
(Cambridge 1998), the Burnham Handbook, or
the Webb Society Observer's Guides.

In making these observations, I have used three or more of the following points:

  • Relative difficulty (given magnification and seeing)
  • Effect of averted vision (AV) and direct vision (DV), (including "on-off" blinking effects)
  • Relative size for object type
  • Shape, elongation and directional alignment
  • Brightness and density (of nucleus, core and halo)
  • Stellaring of nucleus (galaxies) or visibility of central star (planetary nebulae)
  • Ability to resolve into stellar points (globular and open clusters)
  • Number of stars (open clusters)
  • Effect of different eyepieces and filters on appearance
   
Star Charts
  Prior to January 2004, all objects were acquired with the star hopping method, using the following charts:

SA:  Star Atlas 2000.0, Wil Tirion, Second Edition, Field Version (white stars on black)
SP:  Skalnate Pleso Atlas of the Heavens - II, Deluxe Edition,
       Antonin Becvar (Epoch 1950.0)
U:    Uranometrica 2000.0 Deep Sky Atlas, Tirion, Rappaport, Remaklus,
       Second English Edition

After January 2004, most object acquisitions made with the new Celestron 280mm SCT (CGE-1100) are device-aided, verified using the Uranometria Star Atlas.

   
Observing Conditions
  Seeing (atmospheric stability) and transparency (atmospheric clarity or clearness)
are rated subjectively on 1-10 scales that are based on the guidelines provided by
the American Association of Amateur Astronomers. I use 1-10 scales because
their meaning is easier to intuit than 1-5 or 1-7 scales, and they provide more
shades of difference.

Seeing is primarily influenced by atmospheric turbulence.  The following scale
is used to rate conditions:

1   Chaotic: lowest power stellar images unsteady
2-3   Severely disturbed: low power planetary/nebulae images unsteady
4-5   Poor: medium powers unsteady
6-7   Good: only high powers unsteady
8-9   Excellent: only highest powers soft
10   Superb: all powers steady

Transparency is influenced by cloud cover, relative humidity, and light conditions
which illuminate airborne particulates, including light pollution, moonglow, and
residual sunlight. The following scale is used to rate conditions:

1   Mostly Cloudy
2-3   Hazy; 1 or 2 Little Dipper stars visible
4   3-4 LD stars; Milky Way not visible
5   4 LD stars; Bright parts of MW visible (Scutum starcloud)
6   5 LD stars; Milky Way visible with averted vision
7   6-7 LD stars; Milky Way visible
8-9   Excellent: 7 LD stars; M-31 visible
10   Superb: M-33 and/or M-81 visible
   
 
Observing Sites
Primary: Littleton, Colorado:  Suburban site west of Denver with 50% tree blockage; dark Southern sky. At best transparency conditions (5) Scutum star cloud can be seen with naked eye, but not M-31.
  Deer Trail, Colorado: Ed Kline Dark Sky Site of the Denver Astronomical Society. Clear horizon in all directions. Light domes from Denver, 40 miles to the W; Colorado Springs 100 miles to the SW; Limon, Colorado 20 miles to the SE. Best transparency: 9
Others: DNM, Colorado -- Dinosaur National Monument, NW Colorado
Fox Park, Wyoming -- in Medicine Bow National Forest (Best transparency: 10)
Karchner Cavern State Park, AZ -- Campground 9 miles S of Benson, Arizona
Lake City, Colorado -- 2 miles W of Lake San Cristobel
 

Object Types

OCl -- Open (Galactic) Start Cluster
GC -- Globular Cluster
PN -- Planetary Nebula
DfN -- Diffuse Nebula
C/N -- Cluster with Nebulosity
Gal -- External Galaxy (Hubble Classification, for shape only:)

E - Elliptical (0 - 8: round to elliptical shape)
S - Spiral
SB - Barred Spiral
I or Irr - Irregular
a - "Early" Type (bright nucleus; arms less developed)
b - Intermediate Type (lesser nucleus; arms more developed)
c - "Late" Type (weak nucleus; arms very conspicuous)
p  or Pec - Peculiar

Images - NED/IPAC
  Unless otherwise noted, images in the Herschel 400 Observing List are positive-image
thumbnails created from negative images in the NASA/IPAC Extragalactic Database.
Comparison of the long-exposure photographs with descriptions help to illustrate the large
differences between visual observations and photographs.

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2006, Darrell M. Dodge