Descriptive information was drawn from The Sky Atlas 2000.0, 2nd
Edition by R. A. Strong and R. W. Sinnott with descriptions by W. Tirion
and R. W. Sinnott (2000, Sky Publishing Corp. and Cambridge University
Press), and Burnham's Celestial Handbook by Robert Burnham, Jr.
(1978, Dover Publications, Inc.).
North is up and east to the left in all photos. Every effort has been
made to display all photos at the same magnification unless otherwise
stated.
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NGC 5272
2009-05-09
White balance = 6000K (Cloudy)
Noise reduction = Off
Prime focus (32.5×)
Created from my forty-six best 20 s, ISO 1600 photos.
I removed a darkframe
and flatfield, enhanced the contrast for each. I averaged the
modified photos in five groups of eight plus one group of six
and enhanced the contrast again. I averaged the combinations
and enhanced the contrast. Finally, I rotated to north-up,
cropped and scaled the image to 33.3%.
Big, bright and attractive, M3 is, justifiably, popular with
amateurs. M3 is about 48,000 l.y. distant and 16´ across
implying it is 220 l.y. in diameter.
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M3 is popular with me too as is evidenced by the photos below in
2005, 2006 and 2009, from left to right respectively.
These photos are fun because they show
how my photography has evolved: the changes between the
first and second demonstrate an improvement in my skill; between
the second and third demonstrate an improvement in my equipment.
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Created by combining four 20 s, f/2.9, ISO 400 photos,
25.0 mm eyepiece (50.0×)
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Created by combining fifty-seven 20 s, f/2.9, ISO 400 photos.
25.0 mm eyepiece (50.0×)
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Created by combining forty-six 20 s, ISO 1600 photos.
Prime focus (32.5×)
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NGC 5904
2009-05-23
White balance = 6000K (Cloudy)
Noise reduction = Off
Prime focus (32.5×)
This is a combination of my sixty best photos.
I removed a darkframe and flatfield, enhanced the contrast for each.
I averaged the modified photos in six groups of ten
and enhanced the contrast again.
I averaged the combinations and enhanced the contrast.
Finally, I cropped and scaled the image to 33.3%.
An easy object with this equipment. Note that the apparent
distribution of stars is skewed to the southeast (lower
left). I've had a fondness for M5 ever since I saw that
Burnham mentions reading Isaac Asimov's Nightfall
shortly after first viewing this object. Although Asimov
probably didn't have M5 in mind when writing his story,
this cluster and that story were linked in Burnham's mind
and, in mentioning this, forever linked in mine.
M5 is about 24,000 l.y. distant and 21´ across
implying a diameter of 150 l.y.
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NGC 6093
25.0 mm eyepiece (50.0×)
Created by averaging five 30 s, f/2.8, ISO 400 photos,
then removing a flat-field and enhancing the contrast.
Like M4, M80 is near the brightest star in
Scorpius,
Antares,
about 4° north-east. Both M4
and M80 are globular clusters and can be spotted with binoculars
using
Antares
as a signpost, but the similarities end there.
M80 appears as one of the smallest, most condensed globulars
while M4 is one of the largest most diffuse.
This is another favorite of mine because, many years ago, I
independently found it one summer evening. Although my next trip
to the library provided its identification, M80 gave me a taste
of the excitement earlier astronomers must have felt.
M80 is 36,000 l.y. distant and 8´ across implying
it is about 80 l.y. in diameter.
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NGC 6121
2009-07-01
White balance = 6000K (Cloudy)
Noise reduction = Off
prime focus with reducer/corrector (54.2×)
Created from the twelve best 20 s - ISO 800 photos. I removed a
dark frame and flat field from each photo and enhanced the contrast.
The modified photos were then averaged in three groups of four
and enhanced the contrast.
I averaged the combined images, removed
a background, enhanced the contrast, adjust the color balance to
make truer whites and applied a 7×7
Gaussian blur. Finally I rotated to north-up, cropped and reduced
the image.
Compared to other globular clusters, M4 appears to have a very
low concentration of stars, but that means it is very well
resolved even with small telescopes. The reason it appears so
large and diffuse is that M4 is close, approximately 10,000 l.y.
distant. With dark skies and binoculars, M4 is quite obvious
about 1° west of
Antares,
the brightest star in Scorpius and little M80
should be in the field of view too.
M4 is 34´ in diameter implying a diameter of about 100 l.y.
NGC 6205; Hercules Cluster
2009-08-02
White balance = 6000K (Cloudy)
Noise reduction = Off
prime focus with reducer/corrector (54.2×)
Created from the forty-three best 30 s, ISO 800
photos. I removed a dark frame
and flat field from each photo, then enhanced the contrast.
I averaged these together in five groups of seven and one group of
eight and enhanced the contrast again.
I then average the six groups and enhanced
the contrast one last time. Finally I rotated the image to
north-up, cropped it and reduced the scale by a factor of three.
larger images
in a new window.
Remarkable in any sized instrument, including binoculars, and
visible by eye from a dark site. Many stars are resolved
so M13 becomes more breathtaking in larger instruments.
M13 is about 26,000 l.y. distant and 20´ across
implying it is about 150 l.y. in diameter.
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NGC 6218
2009-05-23
White balance = 6000K (Cloudy)
Noise reduction = Off
prime focus (32.5×)
This is a combination of my fifty-four best 20 s,
ISO 1600 photos.
I removed a darkframe and flatfield, enhanced the contrast for each.
I averaged the modified photos in seven groups of nine
and enhanced the contrast again.
I averaged the combinations and enhanced the contrast.
Finally, I cropped and scaled the image to 33.3%.
M12 and its nearby fraternal twin,
M10,
reside in a rich area
of the sky. Of particular note is the near-by "high-velocity"
Barnards Star.
M12 is slightly more sparse and slightly
closer than some other globular clusters, so its many stars
are easily resolved.
It is about 16,000 l.y. distant and 16´ across
implying it is about 74 l.y. in diameter.
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NGC 6218
2009-06-30
White balance = 6000K (Cloudy)
Noise reduction = Off
prime focus (32.5×)
This is a combination of my eighteen best 20 s,
ISO 1600 photos.
I removed a darkframe and flatfield, enhanced the contrast for each.
I averaged the modified photos in three groups of six
and enhanced the contrast again.
I averaged the combinations and enhanced the contrast.
Finally, I cropped and scaled the image to 33.3%.
Like its nearby fraternal twin
M12, M10 clearly
has a more "grainy" appearance than some of its siblings.
Being somewhat sparse with many resolved stars, M10 is a wonderful
sight in a small telescope at a dark site.
As mentioned in the description of
M12,
this is in a rich area of the sky and worth examining by
eye, binoculars or telescope.
Although it appears smaller in smaller telescopes, M10 is
about 20´ across. At a distance of 14,300 l.y.,
this implies a diameter of 83 l.y.
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NGC 6341
White balance = 6000K (Cloudy)
Noise reduction = Off
Prime focus (32.5×)
Created from the thirty-five best 20 s, ISO 1600 photos.
I removed a dark frame
and flat field, enhanced the contrast of each photo. I averaged
the modified photos in groups of five and enhanced the contrast.
I averaged the combinations and enhanced the constrast. Finally
I rotated to north-up and cropped the image.
An attractive, concentrated globular cluster but fated to be
overshadowed by nearby M13.
M92 is about 28,000 l.y. distant and 14´ across
implying it is about 110 l.y. in diameter.
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NGC 6656
White balance = 6000K (Cloudy)
Noise reduction = Off
prime focus using a reducer-corrector lens (54.2×)
Created from the fifty-one best 30 s - ISO 800 photos.
I removed a dark frame and flat field from each photo and enhanced
the contrast. The modified photos were then averaged seven groups
of seven, the contrast was enhanced and a residual background removed.
I averaged the combined images, enhanced the contrast and modified
the white balance.
Finally, cropped and reduced the image by a factor of five.
Click the photo to display a
larger image
in a new window.
M22 is a moderately concentrated, bright globular cluster
containing about 70,000 stars. It's total size is huge,
33´ across, about the size of the full Moon, but only the
central portion is easily visible in small telescopes. The
large apparent size is because M22 is one of the nearest
globular clusters: only about 7,800 l.y. distant. This
implies M22 is about 75 l.y. in diameter. It lies in
the general direction of our galaxy's center so it's another
jewel in this very rich part of the sky.
NGC 6715
2009-08-02
White balance = 6000K (Cloudy)
Noise reduction = Off
prime focus with reducer/corrector (54.2×)
Created from the thirty best 20 s, ISO 800
photos. I removed a dark frame
and flat field from each photo, then enhanced the contrast.
I averaged these together in six groups of five and
enhanced the contrast again.
I then average the six groups and enhanced
the contrast one last time. Finally I rotated the image to
north-up, cropped it and reduced the scale by a factor of three.
Although this little fellow appears small and unremarkable, it's
rude to say so because this globular cluster is a visitor. It
probably belongs to the newly discovered Sagittarius Dwarf
Elliptical Galaxy which is interacting with our own Milky Way.
The new data puts M54 at 87,400 l.y., much farther than the
other globulars shown. If M54 were at a similar distance
as the others, it would be one of the most spectacular objects
in the sky.
NGC 6779
2010-07-10
White balance = 6000K (Cloudy)
Noise reduction = Off
prime focus (81.3×)
Created from the fifty-seven best 15 s, ISO 1600
photos. I removed calibration frames, enhanced the contrast and averaged
the photos in groups of five or six. Next, I averaged the groups,
removed a residual background and enhanced the contrast again.
Finally I cropped the photo and reduced its size by a factor of 4.5.
M56 is well resolved but faint so it loses some of its punch.
It gains it back again by being in a rich section of the sky.
Scanning along the Milky Way searching for this globular is always
worth the time. M56 is 8´ across, but I'm capturing only the
brightest, inner 3´ or so. At an approximate distance
of 46,000 l.y., 8´ translates to 90 l.y. in diameter.
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NGC 6809
25.0 mm eyepiece (50.0x)
Created by combining seven 15 s, f/2.9, ISO 400 photos,
then removing a flat-field and enhancing the contrast.
For year, astronomers debated whether M55 was a compact open cluster
or a loose globular clusters. Better technology shifted opinion
to it being a globular cluster and very long exposure photographs
clearly show the globe shape. There just aren't enough brighter
stars in the group to make it evident in smaller telescopes.
M55 is 49,000 l.y. distant and 12´ across implying it
is 170 l.y. in diameter.
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NGC 6838
25.0 mm eyepiece (50.0x)
Created by combining six 30 s, f/2.9, ISO 400 photos,
then removing a flat-field and enhancing the contrast.
Like M55, the exact classification of M71,
loose globular or compact open cluster, was uncertain until
recently. Also like M55, it has been
determined that M71 is a globular cluster. Being faint and
not very compact in a rich field of stars makes M71 a challenge
but it can be rewarding. M71 is 13,000 l.y. distant and
7´ across implying it is 30 l.y. in diameter.
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NGC 7078
2008-09-27 03:41 - 04:10 UTC
25.0 mm eyepiece & + barlow (80.2×)
Created by averaging twenty-one 60 s, f/2.8, ISO 400 photos
in groups of four (and one group of five), removing a flat-field
and enhancing the contrast. The groups were then averaged, the
contrast enhanced again and an unsharp mask (3.0, 0.5, 0) applied.
The brightness and compactness of M15 makes it one of the
most popular globular clusters in the north. M15 is 50,000 l.y.
distant and 18´ across implying a diameter of
250 l.y. It contains a very small planetary nebula but
because of resolution limits and chromatic abberation, there
is no chance of detecting it in this photo.
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NGC 7089
White balance = 6000K (Cloudy)
Noise reduction = Off
prime focus (81.3×)
Created from the fifty-three best 15 s - ISO 1600 photos.
I removed calibration frames from each photo and enhanced their
contrasts. I averaged all photos together, strongly enhanced the
contrast and removed a residual background. The center of the cluster
was saturated so I masked and combined the image with a less enhanced
version of itself to show the structure towards the center of the
cluster. Finally, I rotated the image to north-up and cropped the
image by 4.5.
Click the photo to display a
larger image
in a new window.
A large globular cluster with many resolved stars even in a
small telescope. M2 is 15' across. At a distance of 55,000 l.y.,
this implies it is 240 l.y. in diameter.
Last modified: 2010-11-07