NGC2903

 

 

RA: 9hrs 32min 12secs      Dec: 21º 30' 00"    Mag: 9.0   Distance: 25 million light years   Constellation: Leo

 

This spectacular obliquely oriented spiral galaxy in Leo is probably the brightest of the Leo galaxies.  It is therefore surprising that it was not discovered by Méchain or Messier, but by William Herschel 3 years after Méchain recorded M65, 66, 95 and 96, in 1784.  This galaxy is classed as a Sb spiral and has numerous HII rich regions.  This image was made on the 27th of April 2006, 2 nights after the photos of M95 and 105.  The viewing conditions were the same as 2 nights previous with very light breezes, cloudless sky but haze present causing the sky background to have an orange glow from nearby Abingdon lights.  The moon was very early first quarter and well set by 11pm. 

This image is the product of 6 separate Envisage photos taken at f6.3, each consisting of multiple 21.2 second exposures as follows, 25x, 31x, 39x, 51x, 16x and 44x, making a cumulative exposure time of just over 72 minutes.  Re-centering of the image was required after each Envisage exposure set because of my constant problem of vertical drifting of the LX90 whilst in equatorial mode.  I don't know how to fix this problem as alignment according to the Meade instructions is faultless, as is GOTO accuracy.  Prior to stacking in Maxim DL each of the 6 images was treated as follows - the galaxy and arms were carefully selected out and the skyglow was reduced by using the Curves command in Photobox in the Red and Green channels only.  This was carried out with only minimal loss in the object.  Following stacking the midtones were enhanced behind a layer mask configured more for the light background than for the stars or galaxy core.

 

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