Event Date: August 6th
Time: 6:00 AM
Brief
At the end of yesterday's Summer Triangle entry, while talking about light refraction through our atmosphere for some stars, I mentioned Sirius, in comparison with some-what dimmer Vega. While the latter sets in the west-northwest at this hour, Sirius is about 180º apart azimuth-wise, rising in the east-southeast. The "dog star" follows Orion, which I featured back in July and now getting higher in the twilight sky. Seeing Orion (no stick-figure this time) rising reminds us that we are entering our later months of the year, since it is a winter-riser in the evening. Also, as seen in the image of both, look at Venus and Jupiter high above them. What do you notice with them and Sirius on the rise?
Time: 6:00 AM
Brief
At the end of yesterday's Summer Triangle entry, while talking about light refraction through our atmosphere for some stars, I mentioned Sirius, in comparison with some-what dimmer Vega. While the latter sets in the west-northwest at this hour, Sirius is about 180º apart azimuth-wise, rising in the east-southeast. The "dog star" follows Orion, which I featured back in July and now getting higher in the twilight sky. Seeing Orion (no stick-figure this time) rising reminds us that we are entering our later months of the year, since it is a winter-riser in the evening. Also, as seen in the image of both, look at Venus and Jupiter high above them. What do you notice with them and Sirius on the rise?
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| click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp. |
Detailed
Throughout June and July, we have seen Venus pull away from Jupiter gradually, and faster now since it is much closer to us and moves faster in prograde. The two are now separated by 18º, after being less than 5º in late June. However, look at Sirius, and remember how it is rising about four minutes earlier each morning. Therefore, along with the movement of Venus and having the Summer Triangle in the west, do we have another easy-to-see triangle in the sky?? It seems that way, as it become more defined throughout the month. In a couple of weeks, it is a fun target, which will be above the horizon while the Vega/Deneb/Altair trio still is, seen from our latitude. How many evenings can you see both?? Also, when Mars isn't having one of its closest oppositions, Jupiter is brighter than it. Sirius at magnitude -1.5, Venus being ranging -3.8 and -4.9 and Jupiter (range -1.8 to -2.9) are--on average--the three brightest targets in the sky after the Sun and Moon.
Keep watching Sirius while Venus pulls away from Jupiter. By September, we have a very attractive isosceles triangle. Can you predict the exact date of that? The "other" triangle will cover a huge amount of sky, and moreso than the standard triangle of the aforementioned dimmer stars.
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