Moonsighting for Jumada-al-Oola 1436

1436 AH
MUH	SFR	RBA	RBT	JMO	JMT	RJB	SHB	RMD	SHW	ZQD	ZHJ

Our very experienced observer Jim Stamm saw the old Moon Crescent through 8� SC telescope on Wednesday; February 18, 2015 at 06:47 am (Local time) in Tucson (Windy Point), Arizona (USA) [Longitude = 110.71 W; Latitude = 32.36 N; Elevation = 2003 meters; Time Zone = -7.0 hours. Age of new moon was 11 hrs 41 min. Moon lag time was 28 min. Relative Altitude was 5.6�.

Crescent first observed through 8� SC telescope at 06:45 am; Moon Altitude was 0.9�. Final observation with telescope was at 06:47 am; Moon Altitude was 1.3�. This was a most interesting and rewarding observation. It became a priority for Mt. Lemmon because the first sighting of a crescent under 7� was made under similar conditions from the same place, and this elongation was close to 6�, significantly less than the 6.5� elongation observed previously.

Planning was meticulous, with a couple of dry runs at the desk the day before. The sky looked great the next morning, and the temperature on the mountain was warmer than expected. Aligning the scope took a little longer than usual, but all of the following steps went off without a hitch. The only element that did not cooperate was the limiting magnitude. I was charting 10th magnitude stars, but I was only seeing 8th magnitude. That prepared me for a negative observation. However, I was pointed really close to the horizon - still in the �red zone,� so 10th magnitude was overly optimistic. Only one or two of my confirmation stars showed up in the field of view. That was OK, because I was already locked on the correct location - even two minutes earlier than planned. Only the focus remained a little less than assured.

When the time came (06:40 a.m. local) to engage the clock drive set on lunar motion, I still hadn�t seen anything except a lot of those �false crescents�. The physiology of the eye is diabolical, creating arced images just the size of the expected crescent. Fortunately they were whiter than real crescents are, and they were of the wrong orientation.

Then at 06:45, after getting above the �red zone�, some of the �false� crescents began showing up in the right orientation, and at the right spot in the field of view. They were not as bright, and much shorter in arc-length, and more importantly, they lasted long enough to see them vibrate when I tapped the telescope tube. This still wasn�t long enough for me to confirm that I had seen the crescent, but they were multiple, periodically appearing for the next two minutes. Taken together I was confident that my sightings were real. I had observed a crescent with an elongation of 6.1� from the sun .... EXCEPT .... the dust specks on the lens of the eyepiece showed that the crescent had moved about an arc-minute or so during those two minutes. The movement was up, away from the sun.

The drive was set on �Lunar�, so the scope should have approximated the moon�s movement toward the sun. That drive movement is constant, while the actual apparent velocity of the moon is variable, so I will need to determine if that factor can explain the movement in the field of view. Also, refraction is a significant factor near the horizon, so I�ll need to determine if that could account for an arc-minute or so. Generally, the effects of refraction should be the opposite of what I observed. If anyone can help me out by suggesting other factors, I�d appreciate it.

Overall, the impression of this observation was that this first sighting was similar to the last sighting of some previous old moon crescents, where I would follow them up, tapping the scope for as long as possible, sometimes even observing after sunrise. If I can resolve the conundrum of the apparent aberrant movement of the old moon crescent, and then observe tomorrow�s new moon around noon, I may be able to observe �opposing� moons in less than 30 hours.

New Crescent Moon for Jumada-al-Oola 1436

The Astronomical New Moon (conjunction) is on Febraury 18, 2015 (Wednesday) at 23:47 UT. On Feb. 18, there is no possibility of sighting anywhere. On Febraury 19, 2015 (Thursday) the moon can be easily seen in North America, Central America, and part of South America; this moon may be seen with difficuly in Europe. On Febraury 20, 2015 (Friday), the moon can be easily seen in the whole world (See visibility curves).

The earliest reported sighting of the new crescent was on Febraury 19, 2015 from Clermont Ferrand, France by naked eye.

No sighting reports were received on February 18, just as predicted by visibility curves.