Visual Astronomy from a Professional Astronomer

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Visual Astronomy from a Professional Astronomers
Perspective

• Ron Buta
• University of Alabama

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Prior to 1985, much professional observing had a
strong visual component
- photoelectric photometry - photography
Photometers and cameras often had widefield
offset guider eyepieces with crosshairs for
visually centering a target on the detector ,
focussing, and finding guide stars if needed.
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Photoelectric photometry the technique of using
a photomultiplier to measure the apparent
brightnesses of celestial objects. Multi-aperture
photometry the technique of measuring apparent
brightnesses of galaxies in a series of circular
diaphragms of increasing diameter, to allow the
fitting of growth curves to extrapolate total
magnitudes and color indices.
Photoelectric photometry of galaxies required
considerable visual observing expertise. Galaxies
had to be visually centered on crosshairs, then
peaked up in a small aperture. This was
especially challenging for low surface brightness
or very faint galaxies.
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McDonald Observatory - West Texas
36-inch dome 82-inch dome
36-inch telescope
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30 McD
82 McD
107 McD
40 SSO
24 SSO
30 MSO
SSOSiding Spring Observatory, Australia MSOMount
Stromlo Observatory, Australia
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1970s-1980s Galaxy
Photometry 1. To measure galaxy brightnesses
effectively, especially low surface brightness
galaxies or 14th magnitude and fainter average
galaxies, dark time was essential. Any light
pollution (moon or otherwise) made measuring such
galaxies using visual centering difficult to
impossible, and reduced signal-to-noise ratio. 2.
On a dark photometric night, anything one
measured was seen under the best possible sky
conditions. 3. Partly cloudy nights or parts of
nights sometimes allowed plain visual observing.
The sky was not photometric at these times but
was still very dark and could be used for basic
curiosity observing.
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DDO dwarf project 1978-1981 with G. and A. de
Vaucouleurs - low surface brightness late-type
galaxies - proper photometry - 100 measured
(by me), half actually seen visually - dark
adaptation very important!
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Typical checklist for standard star photometry of
galaxies
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Growth curve fitting to get total magnitudes and
color indices NGC 1
me(V) 20.88 mag/arcsec2
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DDO 165 (A130467), a visually detectable example
DDO 72A - a small edge-on near the invisible
DDO 72. My first galaxy.
me(V)23.71 mag/arcsec2
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A good observing run (36McD)
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Gallery of visual drawings with large
telescopes - naturally interesting because of the
exceptional light-gathering powers involved and
darkness of observing sites - nothing short of
amazing at what one could see (at least at the
time!)
Of what value is such observing? - fascination
with the heavens is ceaseless and need not depend
only on the collection of scientific data - a way
of connecting with the great observers of the
past (e.g., Herschels, Lord Rosse, W. Lassell,
etc.)
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Birr Castle Leviathan
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Birr Castle sketch of M51 in museum
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. A hasty sketch is made in order to record the
distinctive features as accurately as possible.
One beautiful object having been observed, the
telescope is moved back to the meridian to be
ready for the next vision of delight.
Robert Stawell Ball, Birr Castle Observer
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Scientific Transactions of the Rpyal Dublin
Society, 1880
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DDO 76
DDO 226
DDO 125
DDO 24
DDO 10
DDO 14
Six visually detected and one non-visually
detected DDO dwarfs
36 McD
NGC 3664 DDO 95
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NGC 2070 CTIO 36-inch visual September 1981
NGC 2070 ESO VLT BVR composite early 2000
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Orion Nebula
KPNO outreach image (Steinbergs)
McDonald 30-inch visual March 1979
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NGC 4631 30-inch McD visual
NGC 4631 KPNO outreach DiTulio
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M33 B-band 3 Televue
M33 36-McD visual
Resolved supergiants in M33
IC 139-40 stars cloud 36-McD NGC 604
82-McD
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NGC 2403 KPNO outreach
NGC 2403 30-McD visual
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NGC 4449 KPNO outreach
NGC 4449 36-McD visual
Irregular galaxy
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Center of the cluster Abell 262 showing double
galaxy NGC 704
Visual 36-inch McD 360x
NGC/IC project R. Erdmann
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NGC 5189 24-SSO visual
ngcic.org image (PSS)
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NGC 2903 30-McD visual
NGC 2903 KPNO outreach
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NGC 4490 KPNO outreach
NGC 4490 36-McD visual
NGC 4490 LdR
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NGC 3627 M66 30-inch McD visual
NGC 3627 M66 outreach website
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M51 KPNO outreach website
M51 30-inch McD visual
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NGC 2440 36-McD visual
NGC 2440 Wiley
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NGC 5994-6 36-McD visual
NGC 5994-6 Keel
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NGC 1566 40-SSO visual
NGC 1566 de V Atlas
NGC 1566 is an awesome sight. No written
description is adequate to convey the scene when
the galaxy is viewed through an eyepiece at the
focus of a telescope rather than on an electronic
screen. A. Sandage, The Carnegie Atlas of
Galaxies.
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M100 30-McD visual
M100 KPNO outreach Kings
M100 107 McD central ring
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M82 B-band CCD
M82 36-McD visual
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NGC 1300 30-McD visual
NGC 1300 Biess
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M87 36-McD visual, showing optical jet and two
background galaxies
M87 Block
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NGC 3893 36-McD visual
NGC 3893 Uminski
NGC 3893 LdR 1857
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NGC 3372 - S. Quirk
NGC 3372 6-MSO visual
(hands very cold)
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M97 36-McD visual
M97 outreach website (White)
Birr Castle (LdR)
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IC 3949 in Coma Cluster 36 McD
IC 1258-9 36 McD visual. Double-double galaxy,
the epsilon Lyrae of galaxies
NGC 4889 and surroundings 36McD
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Corona Borealis Cluster (Steve Gottlieb webpage)
Corona Borealis Cluster Abell 2065 36 McD visual
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NGC 3242 82 McD visual
NGC 3242 KPNO outreach Block
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M1 36 McD visual
M1 internet image
M1 LdR (R. J. Mitchell)
LdR, P.T. 1844
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NGC 4889 36 McD visual with close double NGC 4898
NGC 4889 de V Atlas image
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NGC 4565 Hugo (KPNO outreach)
NGC 4565 36 McD visual
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M101 S. Hunter 1861 (LdR)
M101 30 McD
M101 Block
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NGC 3646 36 McD visual
NGC 3646 de V Atlas B-band
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NGC 4900 36 McD visual
NGC 4900 de V Atlas B-band
NGC 4900 LdR
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NGC 4725 30 McD, visual
NGC 4725 de V Atlas
NGC 4725 LdR 1858
The centre itself is like an extended nebula
with Nucl. enveloped in an irr ring or rings
somewhat like an anchor
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NGC 4676 107 McD visual
NGC 4676 KPNO outreach
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NGC 4151 30 McD visual
NGC 4151 KPNO outreach
NGC 4151 LdR sketch, showing the ansae
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NGC 5248 30McD NGC 4710 36McD NGC 1365
30McD NGC 4656-7 30McD NGC 7814 36McD
NGC 3953 36McD NGC 3081 30McD NGC 520
30McD NGC 3808 107McD NGC 3718 30McD
NGC 5371 36McD NGC 3631 36McD NGC 1068
36McD NGC 6300 40SSO NGC 3310 36McD
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NGC 2537 36McD NGC 3395-6 36McD NGC 772 30McD
NGC 628 30McD NGC 5394-5 36McD
NGC 4676 107McD NGC 4303 30McD
NGC 4536 30McD NGC 4254 30McD
NGC 908 36McD
NGC 5921 36McD NGC 4736 36McD NGC
5247 36McD
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NGC 1535 36 McD
NGC 6302 40 SSO
NGC 6781 36 McD
NGC 7662 36 McD
NGC 650-1 36 McD
NGC 6337 40 SSO
Six planetary nebulae
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NGC 2371-2 36 McD
NGC 2392 36 McD
NGC 1501 36 McD
NGC 2022 24 SSO
NGC 6894 36 McD
M57 30 McD
NGC 7026 36 McD
NGC 6543 36 McD
More planetary nebulae
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CTIO 4m telescope
NGC 7702, seen visually to look like this at
prime focus of CTIO 4m
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NGC 5364 - two arms one side
NGC 6744 - bar and partial inner ring
NGC 1433 - bar, ring, spots in nucleus
NGC 6300 - inner ring and bar
NGC 7531 - inner ring and one arm
Spirals seen visually at prime focus with CTIO 4m
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Published by Cambridge University Press, February
2007
Gerard de Vaucouleursborn April 25, 1918 Paris,
Francedied October 7, 1995 Austin, Texas
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M27 20-inch Obsession visual
M27 APOD
M27 P.T. 1861 (LdR)
M27 48-inch visual Lassell 1866
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M20 20-inch Dob visual
M20 Castanos
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NGC 7293 web image
NGC 7293 20-inch Dob visual