Thursday, July 16, 2009

Jupiter and Neptune

Between 2:00 and 4:00 a.m. EST early July 5 I took a series of photos of this close planetary alignment. Jupiter was about a half a degree from Neptune and approaching a third of a degree four nights later. I was currently in Wellfeet, MA, on a very windy beach lot, so getting a steady image was difficult. Although both planets were visible in my 35mm Panoptic, I was unable to frame both planets shooting through my attached Canon Digital Rebel. I should have taken an even lower powered photo without an eyepiece simply to orient the separate photos into the correct arrangement, but I had to do it the hard way, and I might be incorrect. The star, Mu Capricorni, is definitely brighter than Neputune, and so easy to establish visual separation. I drew a triangle of the two planets and star from on online map of that night and placed that over my screen, reducing the view size until they matched the sketch and then distanced them the correct amount and angle from Jupiter. The orientation of the moons should be about right since I lined up frame of the Neptune photo parallel to Jupiter's, since I had not turned my camera. In other words this was a painstaking reconstruction, but I am not sue how accurate. The relative magnitudes are exaggerated; I overlayed a shorter exposure of Jupter to eliminate overexposure and show cloud bands, and the moons appear more bloated than in reality, but this was the closest I could get the image to match what I remember seeing.


Blogger jim said...

Incredible picture. What you need to do with Neptune though is to set the transparency of the layer to about 50% or so to make it grayer and subsequently dimmer. Neptune is about 5x further from the sun as Jupiter so it receives about 1/25 the sunlight of Jupiter, and so its surface brightness would be that much less assuming equal albedos.

9:28 PM  

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