Archive for January 2020

NGC 1931 – Bright Nebula and Cluster in Auriga: February 2020 Observer’s Challenge Report

January 23, 2020

 

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

February 2020

Report #133

NGC 1931 Bright Nebula and Cluster in Auriga 

Sharing Observations and Bringing Amateur Astronomers Together

Introduction

   The purpose of the Observer’s Challenge is to encourage the pursuit of visual observing. It’s open to everyone who’s interested, and if you’re able to contribute notes, and/or drawings, we’ll be happy to include them in our monthly summary. Visual astronomy depends on what’s seen through the eyepiece. Not only does it satisfy an innate curiosity, but it allows the visual observer to discover the beauty and the wonderment of the night sky. Before photography, all observations depended on what astronomers saw in the eyepiece, and how they recorded their observations. This was done through notes and drawings, and that’s the tradition we’re stressing in the Observer’s Challenge. And for folks with an interest in astrophotography, your digital images and notes are just as welcome. The hope is that you’ll read through these reports and become inspired to take more time at the eyepiece, study each object, and look for those subtle details that you might never have noticed before.

NGC 1931 

NGC 1931 is a small emission and reflection nebula with an involved cluster. The brightest part of the nebula has a trapezium system at its heart. Somewhat at odds with their name, trapezium systems can consist of more than four stars, and they don’t have to be arrayed in a trapezoidal shape. The term was initially coined to mean “a multiple star system whose pairwise separations are of the same order.” Some later researchers include groups whose stars may not be gravitationally bound. NGC 1931 is roughly 7500 light-years away from us.

William Herschel discovered this NGC 1931 in 1793. His journal entry reads, “Very bright, irregularly round, about 4 or 5′ diameter. Seems to have one or two stars in the middle or an irregular nucleus. The chevelure diminishes very gradually

 

February Observer’s Challenge Final:  Click on the Following link: 

February 2020 OBSERVERS CHALLENGE _ NGC 1931

February:  NGC 1931 – Bright  Nebula and Cluster – Auriga; Mag. V= 10.1;  Size 6′ 

RA:  05h  31m   Dec.  +34º  14′ 

 

The embedded Stars in NGC 1931:  by Sue French   

     Don’t be surprised about not seeing the stars in NGC 1931.  Folks get very mixed results.  Go to http://www.deepsky-archive.com/ and type NGC 1931 in the Designation box, then look at everyone’s sketches.  

     Here’s a long-ago Amastro post from Brian Skiff that gives the magnitudes of the trapezium system embedded in the brightest part of the nebula.  I see one of these stars, or a blend of them, in the 105mm scope.  The 10-inch at 213× gives me six stars in the brightest part of the nebulosity plus several mag 11-13½ stars scattered to the south.  I’ve pasted an image below Brian’s data and labeled the stars on it.  The image is in infrared so that the nebulosity doesn’t blot out the stars. Below the Aladin image is a WEBDA chart showing which stars I saw in the main group through the 10-inch..

     While cleaning up some star-lists, I collected data for stars in the nebulous open cluster NGC 1931 in Auriga.  The group contains a faint trapezium system, ADS 4112, that might be of interest to ‘amastro’ folks. The specs for the group are shown below.  The V magnitudes for the stars come from modern photoelectric or CCD studies.  The separations derive from positions in the 2MASS catalogue, which should be better than the 100-year-old visual micrometry, but which in any case match the old data to within a few tenths of an arcsecond. The brighter trio is straightforward in a small telescope; in 1989 I was able to make out the fourth ‘E’ component very faintly in my 6-inch refractor at 200x.  The very faint, close ‘D’ companion to star ‘B’ doubtless requires a very large aperture.  The data quoted for it is from S. W. Burnham’s work; the magnitude is possibly too bright.  The 2MASS coordinates are listed at the bottom.  Star ‘D’ does not appear in any astrometric catalogue.  The spectral types for the three brightest stars, by the way, are B0V, B0.5V, and B1V.  Thus the object should contain some emission, although there must be a substantial reflection component, since filters do not provide much contrast enhancement.   

\Brian

 ————————————————

ADS 4112 = BD+34 1074:  5 31 27  +34 14.9 (2000)

V mags      sep    pa

AB  11.5,12.3    8″.1  239

AC       13.0   10″.5  310

AE       14.0   14″.6   17

BD      (15.8)   2″.3  322

   

RA   (2000)   Dec

A   5 31 27.08  +34 14 49.6

B   5 31 26.54  +34 14 45.0

C   5 31 26.43  +34 14 56.3

E   5 31 27.50  +34 15 03.2

 

Sue French: Observer from New York

254/1494mm (10-inch f/5.8) Newtonian. Seeing: fair. Transparency: a little better than average.

43×: NGC 1931 is just a short hop westward from starfish-like M36. It presents a small hazy spot surrounding a star.

115×: The nebula spans about 3 arcminutes, and the star now appears triple. Several additional stars straggle south through west-southwest of the nebulous mass.

213×: Six stars are now buried in the nebulosity, three brightest members arranged in a little triangle.

The WEBDA cluster plot below marks the four trapezium-system stars viewed as well as two additional stars spotted within the nebula.

V-magnitudes of the trapezium stars according to WEBDA:

A=11.4, B=12.3, C=13.0, E=14.0. There is a component D in the trapezium system very close to B, but it’s thought to be magnitude 15.8 or dimmer and was not seen. The two arrowed stars were visible: the northern one shining at magnitude 14.1, and the southern one at magnitude 14.5.

After the star-plot is the sketch I made at 213× with the 10-inch scope on 17 February 2020 at 7pm EST. It was a pleasant night for February. The temperature was in the lower 20s and there was no wind. Unfortunately the seeing and transparency were both below average, and there was full snow cover on the ground. I couldn’t see the 14.5-magnitude star mentioned in the previous observation. I decided to sketch just the part of the nebula I could see and the four stars visible within it. My sketch looked pretty good to me, but a scanned image didn’t show the faintest parts, so I penciled over the original sketch to make it scan better, I hope without changing anything too much.

fullsizeoutput_1236Pencil Sketch:  Sue French:

North is up and west to the right

image002

 

 

Mario Motta: Observer from Massachusetts

Taken with my 32-inch telescope, and SBIG STL 1001E camera.  One hour of H-alpha, one hour of Sulfur S2 filters, and only 20 minutes of O3 filter as there was essentially no Oxygen signal.

Processed in PixInsight.

NGC1931

 

Roger Ivester: Observer from North Carolina 

On the night of January 28, 2020, the transparency and seeing were very good.  Using my 10-inch, f/4.5 reflector, NGC 1931 was very easy to locate and see at 57×, appearing as a star with a mostly round halo of nebulosity. 

When increasing the magnification to 267×, using a 12mm eyepiece and a 2.8× Barlow, the bright nucleus revealed a tiny trio of faint stars, with a fourth, much fainter star, toward the WSW.  This fourth star was extremely difficult, and could not be held constantly, but intermittently at best.  The nebula was elongated, with a NE-SW orientation.  

The first time I observed NGC 1931 was with poor seeing, on January 8, 1994, and could not see the trio of stars.  My second attempt to see the trio of stars was in January, 2020, but again with poor seeing and transparency, and was unable to see any of the faint stars.   

Pencil sketch, with the colors inverted:   

 

image001

 

 

 

James Dire:  Observer from Illinois 

NGC 1931 is a mixed emission and reflection nebula with an embedded star cluster found in the constellation Auriga. The nebula is an active star forming region. The complex is located about one degree west and a tad north of the star cluster M36. NGC 1931 also lies 5.75 degrees north and one degree east of the star Elnath. NGC 1931 measures roughly 3 arcminutes in size and lies 10,000 light years away. The nebula is estimated to be magnitude 10.

NGC 1931 contains myriad young, hot O and B stars whose radiation is responsible for the blue hues of the reflection nebula. Four stars in the center of the nebula form a trapezium similar to that in the Orion Nebula. Sometimes NGC 1931 is considered a mini version of the Orion Nebula. A much larger vast region of nebulosity known as IC 417 surrounds NGC 1931. The emissions from IC 417 are the characteristic red colors from H II ions.

My image of NGC 1931 was taken with an 8-inch Ritchey–Chrétien telescope operating at f/6.4 with the use of a focal reducer/field flattener. The camera used was an SBIG ST-2000XCM CCD cooled to -20°C. The exposure was 100 minutes. The bright white area in the center contains the trapezium. The exposure was not long enough to bright out the red emissions of IC 417, which would have filled most of the region captured in this image.

NGC1931

 

 

NGC 1999 – Reflection Nebula With Hole: January 2020 – Observer’s Challenge Report

January 23, 2020

rogerivester

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

January 2020

Report #132

NGC 1999 Reflection Nebula in Orion

Sharing Observations and Bringing Amateur Astronomers Together

Introduction

The purpose of the Observer’s Challenge is to encourage the pursuit of visual observing. It’s open to everyone who’s interested, and if you’re able to contribute notes, and/or drawings, we’ll be happy to include them in our monthly summary. Visual astronomy depends on what’s seen through the eyepiece. Not only does it satisfy an innate curiosity, but it allows the visual observer to discover the beauty and the wonderment of the night sky. Before photography, all observations depended on what astronomers saw in the eyepiece, and how they recorded their observations. This was done through notes and drawings, and that’s the tradition we’re stressing in the Observer’s Challenge. And for folks with an interest in astrophotography, your digital…

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Building a Hot Rod in November 1964: The Beatles Came to America in February of That Year, Cassius Clay Wins the Heavy-Weight Boxing Championship Over Sonny Liston. And I was Eleven Years Old…

January 15, 2020

Date:  November 1964  

     My five older brothers built something similar or akin to what might be called a Rat Rod today.  The origin was a 1951 Studebaker…using the frame, which had been shortened by three feet, the original engine and transmission.  

       In the following photos are my brother Jimmy, who was driving, I’m in the middle with the “cool” cowboy hat, and my brother, Phillip.

     My older brothers, Richard, Jimmy, Ronny, Donnie and Phillip, worked on fabricating “The Bug” as it was called.   I was a bit too young, and mostly just enjoyed watching.  Sometimes I would assist by handing them wrenches or anything else they might need.   

     Improvements were made over the next year with the installation of a mid-50’s Chrysler Hemi engine, which had much more horsepower than the Studebaker.     

     The sad looking tires, especially the front white-walls would eventually be changed out with some better looking wheels.  Additions would also be made to the body, however, still constructed of wood panels.  With a larger budget, many improvements could have been made, but….

     My brother, Donnie, being in high school drove the school bus in the background, which was an early 1950’s model Chevrolet.  

An astronomical telescope purchase in 1963:    

     It was my brother Jimmy, who had already purchased (at the time of the photo) a 60mm f/15 equatorially mounted refractor from Sears, at a cost of $100.  This would be the equivalent of $835 in 2019.  An expensive telescope for sure.

     Two years later, I would begin using this telescope to observe deep-sky objects (galaxies, nebulae and star clusters) and a lifelong interest in astronomy would follow, even to this day.

Roger Ivester   

The Beginning of a Hot Rod

The Beginning of a Hot Rod - 2

  Now going to the future and current:     

     As time progressed, and with an improved budget, greater skills and abilities, my brother Phillip would become a race car and engine builder.  He would also go on to win an incredible 164 drag racing events.    

The following photo was made in September 2019:     

Race Car Wheeley

 

     Phillip still has two race cars, and continues to race this car, as well as his second “almost” identical car, and will race again in 2020.      

IMG_0031

 

IMG_3871

 

 

 

The Three Types of Astronomical Deep-Sky Sketches Identified and Explained

January 5, 2020

rogerivester

     Recently it occurred to me, there is not a definitive identification of the various types of deep-sky sketching techniques.  It’s my opinion, there are basically three types of sketches, but as of current, have never been identified or named.    

     I would like to recommend or propose to the amateur astronomy community, that this identification of deep-sky sketches be considered as a standard for all future discussions and for proper identification, concerning deep-sky drawings.      

     Detailed visual telescope sketching:  Observing an object through a telescope via an eyepiece. Drawing the object on paper or a sketch card “as verbatim” as possible using a pencil, or pencils of various hardness or other.   

     I’m a visual back yard observer with more than forty years of experience.  All of my sketches are made using a pencil and a 5 x 8…

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