Use Venus to Find Neptune

venus-neptune_bino   Saturday morning, 12 April, as the planet Venus rises it will be less than 1 degree from the outer planet Neptune as this graphic shows. The contrast in apparent magnitude (brightness) is quite noticeable as Venus shines with a -4.2 while Neptune ‘shines’ at 7.94. Neptune’s dimness means that it is beyond the range that we are able to see without optical assistance.

   For those keeping count, the difference between each number used in apparent magnitude is 2.512. A difference of 5 is equal to a difference in apparent magnitude of 100. The difference between Venus and Neptune is approximately 12 or 2.512 x 2.512 x 2.512 x 2.512 x 2.512 x 2.512 x 2.512 x 2.512 x 2.512 x 2.512 x 2.512 x 2.512, meaning that Venus is about 63,130 times brighter than Neptune. So even if you cannot see Neptune unless you are looking through binoculars or a telescope eyepiece I think that just knowing that looking at Venus means you are looking toward the outermost of the planets (not counting dwarf planets!) in our solar system.

Click on graphic to see it full size.

Click on graphic to see it full size.

   Venus and Neptune rising together.

   
   
   
   
   
   
   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

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