Starlog January 25th, 2018, 11:15 p.m. local time
On Thursday night, a few hours after I photographed the Orion Nebula, I searched for the asteroid and dwarf planet known as Ceres. Ceres was nearing its current close distance to Earth, so this was an ideal time to find it.
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I had to wait until the location was high in the East, almost approaching Zenith, due to my blocked Eastern view. Specifically, I wanted to ensure that I could identify the front of Leo the Lion, to act as my lower guide, with the stars Castor and Pollux in Gemini framing the top. Though the top of Leo is not very bright, Regulus is, so once I found Regulus, it was easy to star hop to the tip of Leo.
The “tip” star of Leo, as shown above as the last star in Leo connected by the blue lines, is called Algenubi, magnitude 2.95. Looking very carefully, I then found Alterf, a 4.3 mag star, and after that a 4.45 mag double star, as shown by the orange lines. I now knew approximately where Ceres should be.
(It’s worth recalling here that the higher the magnitude number, the fainter the star. The Sun is about -27 magnitude and Pluto around 9, for comparative reference.)
Enter my binoculars, as I had already taken my telescope in for the night because I wasn’t sure if I would still be awake by this time. Consulting with Stellarium, I knew Ceres’s magnitude that night was 6.89, well within my binoculars’ view. Near and above Ceres were a 6.00 mag pulsating variable star (top left, below) and a 5.4 mag star (top right, below), forming an isosceles triangle with the dwarf planet. No other objects in this immediate area were close to Ceres’s 6.89, so identifying this triangle would logically reveal Ceres. And it did turn out to be so, as Stellarium showed:
This was another “first” in that I had never seen an asteroid before. If this were the early 19th century, I’d be saying I had seen one of our 11 or 12 planets in the Solar System. But being 2018, I will settle for witnessing the largest object in the asteroid belt.
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