Event Date: June 7th
Time: 9:00 PM
Brief
Despite the Sun setting about as late as it will all year, and civil twilight nearly at its maximum length for the year, Mercury is separated enough from the Sun to be visible to the eye alone for a very short while. At magnitude -1.0 and starting to dim a little faster each day, these next 7-10 days are the most ideal for trying to find Mercury quickly. Here is Mercury with orbit and celestial guidelines to show its positioning.
Time: 9:00 PM
Brief
Despite the Sun setting about as late as it will all year, and civil twilight nearly at its maximum length for the year, Mercury is separated enough from the Sun to be visible to the eye alone for a very short while. At magnitude -1.0 and starting to dim a little faster each day, these next 7-10 days are the most ideal for trying to find Mercury quickly. Here is Mercury with orbit and celestial guidelines to show its positioning.
Detailed
Notice that Mercury sets not far from the northwest azimuth mark (315º). Right now, it is far enough north on both the celestial dome--and of the Sun for a small amount of time--to spend enough time above the horizon after Sunset. At a little over 25º thanks to a good ecliptic latitude, Mercury reaches its best declination tomorrow evening, just slightly more so than now. The elusive planet sets 67 minutes after the Sun this evening, although still a little over three weeks until greatest elongation. By then, it will be nearly at aphelion and already dimmer than magnitude 0. As mentioned, definitely try to see it over these next few days with the eye alone why still bright enough. The maximum Sunset gap, which I will mention more about in a couple of weeks when it happens, will still be a good time to see it, although we will have better success with binoculars by then.
This second image shows Mercury as a waning gibbous.
Notice that Mercury sets not far from the northwest azimuth mark (315º). Right now, it is far enough north on both the celestial dome--and of the Sun for a small amount of time--to spend enough time above the horizon after Sunset. At a little over 25º thanks to a good ecliptic latitude, Mercury reaches its best declination tomorrow evening, just slightly more so than now. The elusive planet sets 67 minutes after the Sun this evening, although still a little over three weeks until greatest elongation. By then, it will be nearly at aphelion and already dimmer than magnitude 0. As mentioned, definitely try to see it over these next few days with the eye alone why still bright enough. The maximum Sunset gap, which I will mention more about in a couple of weeks when it happens, will still be a good time to see it, although we will have better success with binoculars by then.
This second image shows Mercury as a waning gibbous.
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It is 85% illuminated and an angular size of 5.5 arc-seconds. As a result of being low in the sky towards atmospheric pollution and that small, I will use a field of about 11 arc-minutes (approximately 1/6º). This is a magnification of about 280x, which is ideal in a telescope of 6" or larger. Since Mercury's features--or lack thereof--cannot be seen from Earth, it is okay to use a telescope of low resolution, as opposed to one such as 8 or 10".
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