We bought this home in part for its larger backyard and better views of the sky. Nominally, we are still under Bortle 7-8 conditions with the Milky Way not apparent naked eye. However, the high wall around the yard does block a lot of neighborhood lighting.
Messier 47 First View (18 March)
I participate in the Cloudy Nights discussion board. Thanks to Voyageur responding to the topic "Underwhelmed" in the Beginner's forum, I found Messier 47 in Puppis, 18 March 2022 at 2047 CDT. I viewed it until 2120 using different oculars with my ES 102-mm f/6.47 refractor - 32mm and 14mm with and without a 2X Barlow. The 14mm (82 degrees) alone was best. I counted 40, then 50 stars.
%20c2.jpeg)
Initially, I was not sure if the target was M47 or M46. They are physically close. However, after I came in, I read Wikipedia and the two are distinctly different in view. I did sweep the area several times but did not find Messier 46 that night. I did find it later.
Messier 80 First View (20 March)
I found M80 where I expected it, below beta Scorpii (Graffias, a complex system that I see as a binary), and Antares, about halfway and somewhat inward to the body of the Scorpion. It stood out as a classic globular cluster, a "puffball" with a somewhat brighter center but not to be resolved into individual stars with the small aperture and low magnification (D=102mm; 32mm and 14 mm; 20.625 and 47.14 X). Nonetheless, it was a find and I attribute my success to beginner's luck. Also on the same morning, I first found the small open cluster NGC 6231 near zeta Scorpii. A week later, the mornings were warmer and I sketched the view.
%20c2.jpeg)
The allegedly easier Messier 4 does not appear easily in my sweeps near Antares. Reviewing my logs I located it on 14 July 2015, 11 and 13 June 2020, and 31 July 2021. I found it again on 26 March.
I revisit familiar objects such as the open clusters Messier 44 (“Beehive”), Messier 7 (“Ptolemy”) and Messier 22, in addition to double stars such as Castor (actually six; only two are available for small telescopes), and mu Scorpii, among many others. I am happy to find again targets that I previously logged such as M6 (“Butterfly”) and Messier 28.
Dubhe alpha Ursa Majoris (23 March)
With 32 mm and 14 mm (20.6 X and 47.1 X) oculars I checked Dubhe one of the Pointers in the Big Dipper for a companion star because of the ambiguity in my references. Wikipedia says that it is a spectroscopic binary. Sue French (Celestial Sampler) says that it is "easily split" with the companion 380 arc-seconds away.
At 20.6X using a 50-degree Tele Vue Ploessl eyepiece the active field of view is 2.42 degrees or 145 arc-minutes and I did see another star in the FOV. That was also true with the 82-degree Meade 14-mm eyepiece (yielding 1.74 degrees = 104.5 arc-min). I thought that this was far too wide to be a gravitationally bound binary, but was only another star in the field.
%20c2.jpeg)
However, I had it all along. I just did not have an intuitive grasp of the measurements. I know that 380 arc-sec is 6'20" but I did not relate that to Mizar-Alcor which is an easy standard. Mizar and Alcor (“Horse and Rider”) are the center stars of the Handle of the Big Dipper. In a small telescope, they resolve easily to a three-star system with a binary companion close to Mizar. After using the 14-mm Meade (82-degree) and the 7-mm Nagler Series 1 (50 degree) and drawing those views, I put in a 40mm (SvBony Ploessl) which was a mere 16.5X and the companion was there. I checked Burnham’s Celestial Handbook and he provides an orbit and a separation of 12000 light years.
Messier 46 First View (25 March)
I finally found Messier 46 at 2212 hours. After a half hour of sweeping the area where I expected to find it near Messier 47, I came inside and re-read the instructions in Sue French's Celestial Sampler. I had been making the same error as Messier: I was searching ENE instead of ESE. (The cluster was temporarily lost to the archives because Messier transposed two coordinates.) With the 32-mm TeleVue Ploessl ocular for 20.625X, I counted perhaps 20 stars in the center using averted vision to see some and another 20 all around the periphery. Overall, the open cluster is not as sparkly, bright, and attractive as Messier 47. But there it is.
 |
| Messier 22 in the east top of Sagittarius is a familiar target. |
Messier 81 “Bode’s Galaxy” First View (27 March)
The sky was exceptionally clear for my location. The small, open cluster at the head of Orion, near lambda Orionis (Meissa) stood out. Knowing where it runs, I could almost see the Milky Way. Following instructions on Cloudy Nights posted by Migwan—diagonally across the Bowl of the Dipper, continue the same distance—it took about ten minutes to locate M81. It appeared as a bright-ish round patch with a bright-ish center. I viewed it until 2117. I did not find the nearby companion galaxy M82. When the sky clears later in the week, I will go out again and search.
Observational astronomy has an epistemological foundation: understanding what you are looking at better enables you to see it. One comparison for myself is junior high school woodworking: cut with a saw; take it closer with a file; finish it with sandpaper.
Recent Astronomical Research
As an editor for the History of Astronomy Division of the American Astronomical Society, I usually dragoon other people into writing for the monthly webpage. Recently, I assigned myself several articles. "Planets Have Rings" (here) appeared earlier this month. I am now writing about Agnes Mary Clerke. In July my topic will be the discovery of stellar x-ray sources.
I am awed by what we can achieve now versus what was being done 100 years ago. In Problems in Astrophysics (1903), Agnes Mary Clerke reported on the suggestion of "dark matter." So, even before quantum mechanics informed astrophysics, they were piecing together a coherent view of the cosmos. And they were doing so with instruments far inferior to today's commercial off-the-shelf technology. This photograph was captured by an amateur colleague. Expand the view and you can see a jet of light extending from the lower edge of the galaxy.
%20copy.png)
"The elliptical galaxy M87 is the home of several trillion stars, a supermassive black hole and a family of roughly 15,000 globular star clusters. For comparison, our Milky Way galaxy contains only a few hundred billion stars and about 150 globular clusters. … The jet is a black-hole-powered stream of material that is being ejected from M87’s core. As gaseous material from the center of the galaxy accretes onto the black hole, the energy released produces a stream of subatomic particles that are accelerated to velocities near the speed of light." -- https://www.nasa.gov/feature/goddard/2017/messier-87
PREVIOUSLY ON NECESSARY FACTS
Red Shift: Six Years with Astronomy
Seeing in the Dark: Your Front Row Seat to the Universe
Measuring Your Universe: Alan Hirshfeld’s Astronomy Activity Manual
See also:
Harriman’s Logical Leap Almost Makes It
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.