A harvest moon. The orange color is not due to its being a harvest moon, but is instead due to the fact that it is close to the horizon. [Image from the Wikipedia 'Full moon' page, licensed under GFDL or CC-BY-SA-3.0, via Wikimedia Commons.]
We know that Dollarhyde has an (imagined) relationship with the moon - he kills only during the full moon. In the Graham 'revelation' scene, it is indicated (by Graham) that the Jacobis were murdered on August 1st. Let us consider the year in which Manhunter is set to be 1985 (the movie was released in 1986). According to the U.S. Naval Observatory Astronomical Applications Department,[a] there was a full moon on the night of July 31st, 1985, at 9:41 p.m., so Dollarhyde must have committed the Jacobi murders after midnight that night. The next full moon in 1985 was on August 30th, at 9:27 a.m. The second set of murders, the Leeds murders, were committed on (or within one day either way of) this day in August. The next full moon after this, was on September 29th at 9 minutes after midnight (that is, at 00:09 on September 29th). This was the night Dollarhyde had Reba in his house.
The full moon in late September/very early October occurs close to the date of the autumnal equinox in any given year, and is called the harvest moon. Thus, there was a harvest moon on the night Dollarhyde was menacing Reba. The harvest moon is often mistaken for the modern day hunter's moon, which actually occurs one month later. Hunter's moon is also known as blood moon. As we will see later in the analysis, metaphorically speaking, Dollarhyde 'mistook' the harvest moon for the blood/hunter's moon.
a. U.S. Naval Observatory Astronomical Applications Department, "Dates of Moon Phases". Web. URL = http://aa.usno.navy.mil/cgi-bin/aa_phases.pl?year=1985&month=7&day=1&nump=50&format=p.
