Double Star M40 and Galaxies NGC 4284 and NGC 4290

Observers Challenge report:  MAY 2014 OBSERVERS CHALLENGE – NGC- 4284 – 4290

10-inch reflector from my moderately light polluted backyard with a 5.2 NELM. It was an especially good night with excellent transparency and seeing. 

M40, a pair of 10th magnitude stars, also known as Winnecke 4 is very easy with a wide separation of about 50 seconds of arc. The pair is oriented mostly east-west and both appear as whitish-yellow in color.

Two faint galaxies are located very close to M40.  All three objects (M40, NGC 4284 and NGC 4290) are located within a 1/2º field-of-view.  

I first observed this galaxy pair on March 31, 1994 with visual notes, and many times afterwards, however, it would be February 2000, before I would make my first pencil sketch.  

Just to the west of double star, M40, lies faint galaxy NGC 4290 @ mag. (12.6 and sfc. br. 14.1) elongated NNE-WSW.  A very subtle brightness could be seen in the central region. 

In the “Messier Album” by Mallas and Kreimer:   Expert visual observer “the late” John Mallas, could not see NGC 4290, using a 4-inch f/15 Unitron Refractor.  

Very close and to the west of NGC 4290 is very faint galaxy NGC 4284 mag. (sfc. 14.7) 

Averted vision was required with the 10-inch to see NGC 4284…appearing as a faint, mostly round blur.   Roger Ivester

10-inch f/4.5 Newtonian reflector and 8-inch Schmidt-Cassegrain test comparison:   

During a previous observation from the same location and in a side-by-side comparison with the 10-inch reflector, NGC 4284 could be seen, but only with averted vision.  

However, this galaxy (NGC 4284) was not visible in an 8-inch Schmidt-Cassegrain telescope.

The following sketch was made using a 10-inch reflector @ 142x, pencil and a blank 5 x 8 notecard with the colors inverted using a scanner. 

Sketch:  Very faint galaxy, NGC 4284 is on the western edge and makes a triangle with two faint stars.  Brighter galaxy, NGC 4290 is just to the east from NGC 4284.   Roger Ivester

Spurious M40 and NGC 4290 and 4284 -negative

The following image by Jeff Schilling from Kingwood, Texas (2020)   

8-inch Newtonian reflector.  Orientation of the following image.  Double star M40 is the east, and NGC 4284 is toward the west. I took around 30 subs at 60 seconds each on each R,G,B filter back in February.  Camera: ZWO ASI 1600 mm    


Observing notes and technical information as following by Sue French:  

Our next object is M40, a double star near Delta (d) Ursae Majoris or Megrez.  Oddly, M40 was once considered a non-existent Messier object.  In his 1784 catalogue, Charles Messier described his 40th object as: “Two stars very close to one another and very small, placed at the root of the great Bear’s tail.”  Precessing Messier’s coordinates to equinox 2000 takes us right to such a star pair.  Messier noted this double while searching for a “nebulous star” reported by Johannes Hevelius.  Messier assumed that Hevelius mistook these two stars for a nebula, but the latter was actually referring to a different pair of stars – also without nebulosity.

 To locate M40, start at Megrez and hop 1.1º northeast to 5.5-magnitude 70 Ursae Majoris.  Continue that line for ¼º to arrive at M40.  My 4.1-inch scope at 28´ reveals an east-west pair of 10th-magnitude stars, with the western one slightly brighter.  Through my 10-inch scope, I see the primary as yellow-orange and its companion as yellow-white.  Two galaxies share the field at 118´.  NGC 4290 is a small northeast-southwest oval, and NGC 4284 is a tiny faint spot forming a 1½’ triangle with two 13th-magnitude stars.  The galaxies are about 140 and 190 million light-years away.  Although the distances to its stars are poorly known, M40 is probably an optical (unrelated) pair.

 Independently discovered in 1863 by the German astronomer Friedrich August Theodor Winnecke, M40 carries the double star designation Winnecke 4.  Winnecke is also the original discoverer of eight NGC objects, and ten comets bear his name.  Periodic Comet 7P/Pons-Winnecke is the parent comet supplying the debris for the June Boötids, a highly unpredictable meteor shower with peak rates ranging from 0 to 100 meteors per hour.    Sue French 


Explore posts in the same categories: Work File Only - Observer's Challenge Reports

%d bloggers like this: