Saturday, March 9, 2013

Orion Nebula revisited

Orion Nebula 11second Exp with 500mm f/4.5 lens  iso 8000 
   A few weeks ago I posted a photo of the Orion Nebula, a wispy area of light and clouds of where star formation is taking place. The photo in my January post was taken from my yard where a number of factors such as city skyglow, nearby bright Moon, 15 mph wind and building clouds worked against me.  A month ago I headed to the dark skies Lake Hudson State Recreation Area in  Lenawee County to try to obtain some better photos.  That effort was thwarted as the cloudless sky when I left my house gradually become completely overcast during my 90 minute drive to the site.
   Another month, another waning crescent Moon not rising until pre-dawn hours, leaving the evening sky a inky black backdrop, ideal for astrophotography.  Last night I made it back to Lake Hudson and took some more photos. 

27 second exp @ iso 8000 thru Celstron C-8 2000mm fl @ f/10
   A question I'm often asked about my telescope is 'How far can you see with it?'  Distance is not really the proper measurement of a telescope's effectiveness.  More important are light gathering ability which is calculated by dividing the square of the diameter of the scope's objective lens (or mirror) by the square of the diameter of your eye's dilated pupil.  The equation for my scope looks like this 200mm^2 / 7mm^2 = 846.  Meaning my scope gathers 846x more light than my eye does.
Also resolution gain through the telescope is equal to the objective diameter divided by your pupil diameter, in this case being 200/7= roughly 29x.   Below is an object visible to the naked eye from a dark sky that is over 2,000,000 light years.
The Andromeda Galaxy
  The fuzzy bright spot on the left edge of the photo is a satellite galaxy that orbits the Andromeda Galaxy. Photos taken by real astrophotographers reveal the Andromeda Galaxy spans more than 2 degrees of arc(for reference the full Moon spans 1/2 degree of arc).

  The final photographic target for the night is the Pleiades star cluster, which is an area of recent (on an astronomical scale) star formation.
  Faint clouds of dust  around the brighter stars can be seen in the photo.  That is debris that will eventually fall into the stars or coalesce around the stars to form planets.  The stars in the Pleiades Cluster are around 10 million years old.  It sure is taking a long time for their god to separate their light from darkness.

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