Event Date: October 3rd
Time: 7:00 PM
Brief
Let's see how Mercury is doing, as it slowly emerges south of the Sun, seen here in the west-southwest. As mentioned a couple of weeks ago, Mercury will take awhile this time to reach greatest elongation, as it first reaches aphelion and loops further from us on the other side of the Sun. As it passes aphelion and starts to get closer to the Sun again, it does so when it is not far past greatest elongation, and we start to see it a bigger in angular size than we do at aphelion. Remember of course, that we start seeing the shadowed side of it and therefore, it appears to wane in phase. Therefore, as mentioned with Venus only at 71% yesterday (albeit waxing not waning), we will not see much disc illumination at all from Mercury; hence a rapid dimming shortly after greatest elongation.
Here is Mercury now, showed zoomed out and also in at a low magnification. Notice for the zoom-out, that Saturn is seen just above it, yet dimmer than Merucry (-0.3 this evening). Saturn is about +0.7, roughly twice as dim on the apparent magnitude scale.
Time: 7:00 PM
Brief
Let's see how Mercury is doing, as it slowly emerges south of the Sun, seen here in the west-southwest. As mentioned a couple of weeks ago, Mercury will take awhile this time to reach greatest elongation, as it first reaches aphelion and loops further from us on the other side of the Sun. As it passes aphelion and starts to get closer to the Sun again, it does so when it is not far past greatest elongation, and we start to see it a bigger in angular size than we do at aphelion. Remember of course, that we start seeing the shadowed side of it and therefore, it appears to wane in phase. Therefore, as mentioned with Venus only at 71% yesterday (albeit waxing not waning), we will not see much disc illumination at all from Mercury; hence a rapid dimming shortly after greatest elongation.
Here is Mercury now, showed zoomed out and also in at a low magnification. Notice for the zoom-out, that Saturn is seen just above it, yet dimmer than Merucry (-0.3 this evening). Saturn is about +0.7, roughly twice as dim on the apparent magnitude scale.
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| click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp. |
Detailed
For image one, Saturn is a little further north than Mercury in ecliptic latitude. Therefore, the two never get extremely close together and even if they did, get washed out by the Sun easily. Despite Mercury being brighter, it is far enough south of the Sun right now that a non-obstructed horizon would also make viewing difficult. Over the next few years, we we see closer pairings of Mercury and Saturn, when we see Mercury near it more similar ecliptic latitudes.
As for the second image, Mercury is too small and low in atmospheric pollution to try to magnify too much; even with a telescope that can handle 2-300x, that isn't necessary. As a reminder, Mercury is nearly featureless, resembling our Moon more than anything. Of course, our Moon is so much closer than Mercury is too us, that we can see features on our satellite easily. With Mercury, it has taken the proper type of space mission with necessary protection, to get that close to a planet so close to the Sun.
The zoom-in shows Mercury at 1º, which is about 50-55x in magnification.
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