Sky watchers around the world were treated this month to two full moons, a supermoon and a blue moon. The American space agency NASA explains a supermoon happens when the moon’s orbit brings it closer than usual to Earth at the same time that the moon appears full from Earth. The first supermoon of 2023 was in July. The fourth and last one will be in September. The last time two supermoons appeared in the sky in the same month was in 2018, The Associated Press reports. The next time a blue supermoon is set to arrive is 2037.

本月，世界各地的天空观测者看到了两次满月、一次超级月亮和一次蓝月。 美国宇航局解释说，当月球的轨道比平常更接近地球，同时月球从地球上看起来是满月时，超级月亮就会发生。 2023 年的第一个超级月亮发生在 7 月。第四次也是最后一次将于九月举行。 据美联社报道，上一次同月出现两个超级月亮是在 2018 年。下一次蓝色超级月亮预计将于 2037 年到来。

The first supermoon arrived on the first day of August, while the blue moon was seen beginning August 30. NASA noted that when the blue moon arrived, the planet Saturn was just a few days from its closest and brightest appearance of the year from Earth. Saturn appeared as a bright “star” to the upper right of the blue moon. Italian astronomer Gianluca Masi, creator of the Virtual Telescope Project, held an online watch event as the blue supermoon was setting below the skyline of Rome. But he advised that, as long as the weather was good, world observers looking to the sky would not need any special equipment to see the moons. “Warm summer nights are the ideal time to watch the full moon rise in the eastern sky within minutes of sunset,” said retired NASA astrophysicist and moon expert Fred Espenak.

第一个超级月亮于 8 月第一天出现，而蓝月亮则从 8 月 30 日开始出现。NASA 指出，当蓝月亮出现时，距离土星今年距离地球最近、最亮的位置只有几天的时间。土星以一颗明亮的“星星”出现在蓝月亮的右上方。虚拟望远镜项目的创建者、意大利天文学家吉安卢卡·马西 (Gianluca Masi) 在蓝色超级月亮落入罗马天际线时举办了一场在线观看活动。但他建议，只要天气好，世界观测者仰望天空就不需要任何特殊设备来观看卫星。美国宇航局退休天体物理学家兼月球专家弗雷德·埃斯佩纳克（Fred Espenak）表示：“温暖的夏夜是观看日落几分钟后满月在东方天空升起的理想时机。”

Full moons happen at the exact moment when the moon is opposite the sun, NASA says. Astronomers say a supermoon can appear about 14 percent larger and a bit brighter than other moons.The Old Farmer’s Almanac notes that the August full moon is known as the sturgeon moon. This is because of a traditionally large increase in fish in the American Great Lakes area during the month of August. Although it is called a blue moon, it does not appear blue in color. Instead, the name means it is the second full moon to happen within one month or the fourth to take place in a season.

美国宇航局表示，满月发生在月亮与太阳相对的时刻。天文学家表示，超级月亮看起来比其他卫星大 14%，亮度也稍高一些。《老农年鉴》指出，八月的满月被称为“鲟鱼月”。这是因为八月份美国五大湖地区的鱼类数量传统上大幅增加。虽然它被称为蓝月亮，但它的颜色并不是蓝色的。相反，这个名字的意思是一个月内发生的第二次满月或一个季节中发生的第四次满月。

NASA says the moon takes 27.3 days to orbit Earth, but it takes 29.5 days to complete a full moon cycle. This is what makes it possible to see one full moon at the start of the month and another one right at the end. Astronomers say, however, that the moon can look blue under the right conditions. For example, this can happen as a result of smoke or dust particles in the atmosphere. While the blue supermoon brings the possibility for watching and taking beautiful pictures, its stronger gravitational pull also can influence higher tides. Weather experts advise people living in areas near shorelines to be aware of this, especially during storm activity. There are other kinds of moons that appear at different times.

NASA 表示，月球绕地球运行一周需要 27.3 天，但完成一个满月周期需要 29.5 天。这就是为什么可以在月初看到一个满月，在月底看到另一个满月。然而天文学家表示，在适当的条件下，月亮可以看起来是蓝色的。例如，这可能是由于大气中的烟雾或灰尘颗粒而发生的。虽然蓝色超级月亮带来了观看和拍摄美丽照片的可能性，但其更强的引力也会影响更高的潮汐。天气专家建议居住在海岸线附近地区的人们注意这一点，尤其是在风暴活动期间。还有其他类型的卫星出现在不同的时间。

NASA says a blood moon happens during a total lunar eclipse. This event is when Earth lines up between the moon and the sun, hiding the moon from sunlight. In addition, the term blood moon can also be used to describe a moon that appears reddish because of dust, smoke or haze particles in the sky. A harvest moon is a full, bright moon that appears “closest to the start of autumn,” NASA explains. This name dates from the time before electricity, when farmers depended on the moon's light to harvest their crops late into the night. The moon's light was especially important during fall when harvests are the largest.

美国宇航局表示，血月发生在月全食期间。这一事件是指地球在月球和太阳之间排列，使月球遮挡阳光。此外，“血月”一词也可以用来形容由于天空中的灰尘、烟雾或雾霾颗粒而显得微红的月亮。美国宇航局解释说，丰收月是一轮明亮的满月，看起来“最接近初秋”。这个名字可以追溯到电力出现之前的时代，当时农民依靠月光直到深夜收割庄稼。秋季收获最多时，月光尤其重要。