Doubles in the Crown

by Tom Campbell


June 18, 2003

ObserverTom Campbell
LocationIola, Kansas (Long: 95°24'W Lat: 37°55'N)
EquipmentDiscovery DHQ 8" dobsonian
Eyepieces1.25" Plössls - 25mm (49x), 15mm (81x), 10mm (122x), 6mm (203x), 4mm (305x)
Time10:30pm - 11:30am CDT (03:30-04:30 UT)
TransparencySomewhat Hazy (5/10)
SeeingMostly Stable (7/10)
WeatherTemperatures in the upper 60s. There was little or no breeze.

Observing Summary
CORONA BOREALISZeta, Struve 1932, Struve 1935, Struve 1973

In spite of the cloudless sky, the air was humid and hazy. Nevertheless, it was a nice night, so I went ahead and set up my telescope, hoping to bag a few more Herschels. When twilight ended, I turned my telescope to M13 to gauge the sky conditions. I couldn't see nearly as many stars as I usually could, so I knew that it would be a difficult night. I immediately decided to fall back to Plan B, which was a list of doubles from the "Spirit of 33" for the constellations of Serpens and Corona Borealis.

Serpens and most of Ophiuchus was hidden from view by a large tree, but Corona Borealis could be seen high overhead. Parts of the constellation were in "Dobson's hole," but I felt the need to observe *something*, so I gave it a try.

Struve 1932Corona BorealisDouble Star10:30pm CDT
RA: 15h 18m 18sDec: +26° 50'Mag: 7.4, 7.5

This double was pretty tight. In order to get a decent split, I had to kick the magnification up to 305x, although at 203x, I could tell that it was a double star. Both components were about the same magnitude and appeared white.

Struve 1935Corona BorealisDouble Star10:45pm CDT
RA: 15h 20m 13sDec: +30° 42'Mag: 9.2, 9.4

These stars were fairly dim, and of similar magnitude. The pair was fairly wide and easily split at 81x. Color was difficult to determine at these magnitudes, but both appeared slightly blue-white.

ZetaCorona BorealisDouble Star11:05pm CDT
Struve 1965RA: 15h 39m 22sDec: +36° 38'Mag: 4.6, 5.6

This pair was fairly bright and fairly wide. 81x split the double nicely. The brighter star appeared white and the slightly fainter companion had a slightly yellow tint.

Struve 1973Corona BorealisDouble Star11:15pm CDT
RA: 15h 46m 24sDec: +36° 27'Mag: 7.6, 8.8

This pair was wide, but somewhat faint. It could easily be split at 49x. The brighter star was white or yellow-white, and the somewhat fainter companion appeared blue. The colors in this double were subtle.

Despite the haze and humidity, the temperature stayed well above the dewpoint, so that wasn't a factor tonight. Believe it or not, I was actually hoping for a bit of dew, so I could test out my new homemade dew zapper. Oh well, I'm sure I'll get the chance soon enough. The poor sky conditions and the difficulty I faced in aiming my telescope throughout Dobson's hole finally got the best of me, however, and I decided to call it a night.