NGC 3877 – Galaxy In Ursa Major: April 2020 Observer’s Challenge Report

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York 

April 2020

Report #135

NGC 3877 Galaxy in Ursa Major  

“Sharing Observations and Bringing Amateur Astronomers Together”

 

 

James R. Dire:  Observer from Illinois 

NGC 3877 is an 11th magnitude spiral galaxy in the constellation Ursa Major. To find the galaxy start at the star Megrez, the star where the handle of the Big Dipper connects to the cup.  Follow an arcing line from Megrez through Phecda (bottom star in cup below Megrez) curving south to the third magnitude star El Kaphrah.  The three stars are close to equally spaced with El Kaphrah a tad dimmer than Megrez.  NGC 3877 is a mere 17 arc minutes directly south of El Kaphrah, making it one of the easiest 11th magnitude galaxies to find star hopping.

NGC3788 is a nearly edge on spiral galaxy 5.4 arc minutes long and 1.2 arc minutes wide. The galaxy is classified Sc, which means is has a very small core surrounded by whirling spiral arms. William Herschel discovered NGC 3877 in the year 1788 using his 18.7-inch Newtonian.

Through an 8-inch telescope the galaxy looks cigar shaped with a bright stellar-looking core. No detail can be seen in the spiral arms. 

I imaged NGC 3877 with an 8-inch f/8 Ritchey–Chrétien Cassegrain (with a Televue 0.8x focal reducer/field flattener yielding f/6.4) using an SBIG ST-2000XCM CCD camera.  The exposure was 180 minutes.

To image this galaxy with a reflector is tricky because if you don’t get the star El Kaphrah out of the field, the required exposure to pick up the galaxy would cause the star to drown out the image.  In my image the bright star near the top of the image is 8th magnitude SAO43884.  El Kaphrah is outside of the field of view straight above (north) of the galaxy.  During my three-hour exposure, ghost reflections of El Kaphrah appeared on the image as well as two bright diffraction spikes from my secondary mirror spider.  I removed those from the final image.

About 5 arc minutes to the northwest of the core (upper right) lies a magnitude 9.9 star with four diffraction spikes. Just below this star is a magnitude 16.7 star that is very red in color.  Just at the edge of the lower right diffraction spike is an even very fainted red star shining at magnitude 17.7.  This is one of the faintest stars in the image

The image picks up the tightly wound spiral arms of the galaxy. In between the arms are several dark dust lanes.  The three stars that appear on the outskirts of the galaxy are Milky Way foreground stars.

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Mario Motta:  Observer from Massachusetts

Taken last night (March 27-28) through 32-inch telescope.  Five min subs, total 60 minutes integration time. 

Camera is my new ZWO ASI6200.   Processed in PixInsight.   

NGC3877

 

Roger Ivester:  Observer from North Carolina 

Telescope:  10-inch f/4.5 reflector:  Date: February 22, 2020  

NGC 3877.  Dim slash with very low surface brightness, oriented NE-SW with a subtle brightening in the central region along the highly elongated core.  The galaxy arms show some mottling and uneven texture.  

Pencil sketch:  5 x 8 blank note card with the colors inverted:  

image001

 

 

 

Glenn Chaple:  Observer from Massachusetts 

The best star-hops are those that require no hopping at all. Such is the case with this month’s Observer’s Challenge, the near edge-on spiral galaxy NGC 3877. Center the magnitude 3.7 star Chi (χ) Ursae Majoris in the field of your scope’s finder and then peer into the eyepiece. If your eye is properly dark-adapted, you should see an oval haze just ¼ degree to the south.

In March of 1998, a supernova appeared in NGC 3877, quickly reaching 12th magnitude. It was visible in my 4-inch f/4 rich-field reflector (Edmund Scientific’s Astroscan), as was the galaxy itself. To see NGC 3877 with such a small aperture demands dark-sky conditions. In Vol. 2 of The Night Sky Observer’s Guide, authors George Kepple and Glen Sanner note that an 8 to 10-inch scope will reveal the galaxy’s central condensation, while scopes with twice the aperture should bring out the mottled appearance of its outer regions.

NGC 3877 was discovered by William Herschel on the night of February 5, 1788. Along with M109, it belongs to the Ursa Major Galaxy Cluster. Its distance is variously recorded as 42 to 50 million light years. If at the latter distance, NGC 3877 would span some 80,000 light-years.

Finder charts for NGC 3877 below. Bright star in right-hand chart (from AAVSO Variable Star Plotter) is Chi (χ) UMa. Numbers refer to magnitudes of field stars. North is up in this 25′ by 30′ field.

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NGC 3877 and supernova 1998S, March 25, 1998. Magnification 74× FOV 20. North is to the right.  Sketch by Glenn Chaple (ATMoB)

 

Uwe Glahn:  Observer from Germany 

Objekt: NGC 3877

Teleskop: 27-inch  f/4.2 Newtonian 

Vergrößerung: 293x – 488x

Filter: /

Bedingungen: fst 6m5+

Seeing: III

Ort: Sudelfeld

Inverted Pencil Sketch: 

NGC3877_ug

 

 

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