Event Date: April 30th
Time: 7:58(.55) PM
Brief
After several months of catching up with us in orbit, Venus is not quite there yet. However, it has come close enough to us that we see the most angular surface area. As I have mentioned a couple times over the last couple of weeks, this lit-area facing us is known as greatest brilliancy. Remember that this is not the same as Venus being its best apparent magnitude for this part of the cycle, although we are very close to that as well. To our eyes, it looks as bright as it will for the remainder of the spring. Using the area of a circle and factoring in percent illuminated, we have an angular area this evening seen at Sunset, of 306.1. This number will slowly shrink for the next few days, and then more rapidly. For every time Venus drops in percentage illuminated, that overrides its slower rate of increase for angular size.
Image one shows a reminder of Venus' altitude at Sunset, while image two shows a 1/4º field of the planet's waning crescent phase--only 27% illuminated with an angular diameter of 38 arc-seconds.
Time: 7:58(.55) PM
Brief
After several months of catching up with us in orbit, Venus is not quite there yet. However, it has come close enough to us that we see the most angular surface area. As I have mentioned a couple times over the last couple of weeks, this lit-area facing us is known as greatest brilliancy. Remember that this is not the same as Venus being its best apparent magnitude for this part of the cycle, although we are very close to that as well. To our eyes, it looks as bright as it will for the remainder of the spring. Using the area of a circle and factoring in percent illuminated, we have an angular area this evening seen at Sunset, of 306.1. This number will slowly shrink for the next few days, and then more rapidly. For every time Venus drops in percentage illuminated, that overrides its slower rate of increase for angular size.
Image one shows a reminder of Venus' altitude at Sunset, while image two shows a 1/4º field of the planet's waning crescent phase--only 27% illuminated with an angular diameter of 38 arc-seconds.
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| click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp. |
Detailed
Although still impressive, with Venus being as bright as it is, evening twilight duration increasing is means that we have to wait slightly longer each evening o see Venus with the unaided eye. By the time that we do, it appears a little lower to the horizon than it did the day before. This will become much more obvious over the next few weeks, and especially when Venus goes retrograde and seemingly "dives" towards the Sun and its glare. With that said, this is likely the last best week to view Venus at both (a) its most luminous and (b) high enough up to see long into the evening for a long time. As Venus continues to increase in northern declination, we have nearly 15 hours of it above the horizon, whether day or night! The declination peek for Venus happens later this week, and I will show the positioning of it in more depth, at that time.
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