August 2016

A quiet month, with just one section member contributing four images.  I was able to take deep sky images over two evenings however, increasing the total to ten.

Ian Papworth took images of three planetary nebulae and a globular cluster.  First is M76, the Little Dumbbell planetary nebula in the constellation of Perseus.  Next is M27, the Dumbbell in Vulpecula, which is 2.5 magnitudes brighter and about 4 times bigger in angular size, so much easier for visual observers to detect.

M76
M27

 

 

Ian’s third image is NGC 7662, the Blue Snowball planetary nebula in Andromeda.  A favourite with visual observers, the slightly blue disc may be seen through a small telescope.

NGC 7662

Last is M92;  this less well known globular cluster in Hercules is a fine object but with M13 nearby it is sometimes overlooked.

M92

 

I was able to observe on two nights late in August and took six images with a 305 mm SCT and DSI II camera.  Three were of objects in the constellation of Delphinus;   planetary nebulae NGC 6905 and globular clusters NGC 7006 and NGC 6934.

NGC 6905

NGC 6905 is also known as the Blue Flash, and has a central white dwarf star with a temperature of 150,000 degrees Kelvin.

NGC 7006

NGC 7006 is a distant globular, some estimates place it at over 180,000 light years from the Earth.

NGC 6934

NGC 6934 is about three times closer to us than NGC 7006.

NGC 6886

Planetary nebula NGC 6886 looks quite star – like in this image, so much so that I’ve added an arrow to locate it in the star field.  It is about 10,000 light years away, and the slightly oval brighter inner part captured here is only 2 arc seconds across.  NGC 6886 is in Sagitta.

 

 

 

The remaining two images are NGC 6712,  a globular cluster in the constellation of Scutum, and Palomar 9, a much fainter globular in Sagittarius.  Palomar 9 is the cluster of faint stars below and slightly to the right of the bright star.

NGC 6712
Palomar 9

The Palomar globular clusters were discovered on the first Palomar Observatory Sky Survey photographic plates, in the 1950’s.  They are either distant, in the outer galactic halo, or like Palomar 9, nearby average globulars heavily obscured by interstellar dust and gas.

 

 

Dave Finnigan