Popular Astronomy

August 2014

During August, Steve Norrie sent in three images.  Steve made his observations from Fife, Scotland, using a Skywatcher EDR80 refractor and a Canon 1100D DSLR, modified for atronomical use.  The first, the Pelican Nebula, is shown below left:

This emission nebula also known as IC5070 can be found in the constellation of Cygnus, near to first magnitude star Deneb.  It is separated from the North America Nebula, NGC7000  (Steve's second image, right)  by a dark lane of dust. 

The North America Nebula is also an emission nebula;  both appear reddish due to the ultra violet radiation of hot stars ionising clouds of hydrogen gas, forming what is known as a H II region. (H I is neutral atomic hydrogen, H2 is molecular hydrogen)

H II regions emit light of wavelength 656.3 nanometers in the red part of the electromagnetic spectrum.                                                 



Steve's final image is of the Ring Nebula M57 in Lyra, a  planetary nebula situated south of Vega and between Beta and Gamma Lyrae, so quite easy to find.  It is about 1.5 x 1.0 arcminutes in angular size, so needs a small telescope and a magnification of around 100x to see it properly.


 Eddie Carpenter observed and drew Comet Jaques (C 2014 E2) from Porthcurno in Cornwall on 23rd August.  He used 13 x 70 binoculars, and reported that no nucleus was visible.


The Section Director imaged three Planetary Nebulae during the month. Below left is NGC6781, a PN in the constellation of Aquila,;  it is 108 arcseconds in diameter so bigger than M57 (86 x 62 arcsecs) but much fainter at magnitude 12 (M57 is mag 8.8).  Below right is the Cat's Eye Nebula, NGC6543, in the constellation of Draco.  At 6 srcseconds this object is very small, but at magniude 8.0 more easily seen, looking starlike in small telescopes.                                                                                                                                                                                                                                                                            

                                                                                                                                                                                                                                                                                                                                                                                                     The third image is of PN NGC7008, also known as the Foetus, and it is in the constellation of Cygnus.  This PN is 86 arcseconds in diameter, and is magnitude 10.7.  The central star is magnitude 14. 



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