2017, July: Sun and Moon


Sun

During July, the length of sunlight continues to be long, slightly over 15 hours in the mid-northern latitudes.  The sun’s position along the horizon at sunrise and sunset move about 7 degrees southward during the month, a small but noticeable amount.  In June, the sun appeared to move about 2 degrees along the horizon, that’s about the distance equal to two dimes held at arm’s length.  For most purposes, imperceptible.

By July’s end length of daylight shrinks by about 30 minutes.

 

Moon

NASA Photo

 

Phase Date/Time Moonrise Moonset
Full Moon 07/08/17 (11:07 p.m.) 8:02 p.m. 5:55 a.m. (07/09)
Last Quarter 07/16/17 (2:26 p.m.) 12:12 a.m. 1:03 p.m.
New Moon 07/23/17 (4:46 a.m.) 5:52 a.m. 7:43 p.m.
First Quarter 07/30/17 (10:23 a.m.) 1:26 p.m. 12:28 a.m. (07/31)
Times are Central Daylight Time for Chicago, Illinois, from US Naval Observatory calculations.
(For mjb & afb)

Important Note:  Many calendars may list July 1 as a First Quarter Moon date.  These designations can be tricky, especially when considering a view of moon phases within the context of a calendar month.  In these articles, times are determined for the Central Daylight Time Zone (CDT).  A First Quarter moon occurs on June 30 at 7:51 p.m. CDT.  In parts of the world east of North America, the date is July 1.  When the moon rises on July 1, it will appear half full, the quarter phase.  The times of “exact’ phases are determined by angles between the sun, earth and moon. Several religious calendars build their sacred dates around the phases of the moon.  Since the cycle of phases last 29.5 days and a calendar month can have 28-31 days, the lunar phases do not necessarily consistently match (e.g. having the 1st day of the month start with the new moon.)

For more information about sky watching events:

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