Crab Nebula (M1) before Sunrise

Event Date: July 17th
Time: 5:00/5:43(.34) AM



Brief

   Yesterday, I ended the entry with a mention of a "smudge" in the first image shown there; today I will identify it.  As seen in small telescopes, the Crab Nebula doesn't look colorful, although large telescopes help give it a slightly pink-purple hue; stacked photos can reveal this also.  Overall however, just viewing the nebula, it looks grey.  The nebula is 1.1º from star Zeta Tauri mentioned yesterday while being occulted by the Moon.  The first image below uses a 2º field showing both the star and "Crab".  The time for this entry is 30 minutes earlier than yesterday, to show a darker sky for seeing the Nebula.  As mornings pass, with later Sunrises and the nebula higher before Sunrise each day, it will be further out of atmospheric pollution and look much more clear.  As seen in the first image below. It is 7.5º high at the time above.

Detailed

   This next image is a more impressive view of the Crab, showing more color.  The field of view is 1/2º, which is of magnification of about 120x, To obtain such a view, a telescope of at least 10" minimum is recommended, to gather enough light and not sacrifice contrast in the meantime; finding the happy medium helps seeing the Nebula very well, and especially when it reaches high altitudes.
   Now, how long has this nebula been viewable?  It is the remnants of a star which exploded as a supernova nearly 1,000 years ago (1054).  At 9th magnitude, it is not visible to the eye alone under even the darkest of skies.  At 11 arc-minutes, it is 1/3º the angular size of a full Moon at perigee.  Find out more about the nebula here, also numbered by Messier as the 1st in his catalog.  If you recall from my M3 entry during the spring however, that globular cluster was the first he discovered, not numbered.
According to the info about the Crab provided by the software, "he observed this nebula when he was searching for Halley's Comet in 1758, inspiring him to develop a list of celestial objects that may be mistaken for comets".  Hence, the Crab being the 1st,

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.