The Henry Coe parking lot was packed with cars and telescopes when I arrived shortly after sunset Saturday night. Spring has arrived in force after several months of poor observing condtions, and many observers came out to take advantage of warm termperatures, a clear Saturday night near a new moon, and a possible Messier Marathon.
High cirrus clouds had plagued skies during most of the day, and cloud bands obscured horizon views to the west at sunset, a poor start for the Marathon. On the other hand, winds were low, temperatures were high, and much of the sky was reasonably clear and dark to the north and east, (by far the best viewing direction from this near town location). I decided to forego the Marathon and search for Herschel 400 objects instead in the darkest region of the sky.
Last year, poor observing conditions through most of the spring left huge gaps in the objects I had observed in Ursa Major, Canes Venataci, Coma Berenices, and Virgo. I spent most of the night observing objects at the boundaries between Ursa Major, Canes, and Coma (all pre-marked with yellow post it notes on the charts of the HB Astroatlas). Between 7:30 and 1:30 am I logged and made crude sketches of 31 new objects using a 7 inch Starmaster Oak classic, mostly H400 galaxies and whatever else looked interesting nearby on the charts. For breaks now and then, I also toured 20 or 30 old favorites from the Messier list, making a nice combination of differnet kinds of objects for the night.
The H400 list is full of buried treasures. Perhaps 10 -20% of the objects are as spectacular as the best of the Messier objects, but are hardly ever observed. As a result, every night with the H400 list usually uncovers something special. Last night, the standout view was the area around NGC 4631 in Canes. This huge, bright, elongated galaxy extends as a mottled gash of light from E to W over 20% or more a low power eyepiece view. Like the Milky Way and Andromeda galaxies, NGC4631 has several companion Galaxies that add to the beauty of the view. The most obvious of these is NGC 4656/57, itself an irregular interacting galaxy pair. At low power the NGC 4656/57duo shows up as a slightly bent band of light highly elongated from NE to SW and visible in the same eyepiece view as NGC 4631. Together, these galaxies make a low power view everybit as striking as the well known M65,66 pair in Leo, or M81 and M82 in Ursa major.
And higher power shows even more. Just off the N side of the middle of 4631 lies a pretty pinpoint star. A bit further to the S and W, lies NGC 4627, a mag 12.4 dwarf companion galaxy not included on the H400 list. I could just make this out as a faint circular puff of light with averted vistion last night at Coe. Both NGC 4656/57and NGC 4627 are physically interacting with NGC 4631. The two giant galaxy systems are located within 100,000 light years according to Tim Ferris’ Galaxies book, and are closer than the distance between the Milky Way and the Magellanic clouds. Burnham’s has a picture of the individual galaxies, but no text devoted to the system. The Night Sky Observer’s Guide has a low power plate that includes both 4631, its tiny companion 4656/57, and the 4656/57 duo. This set of objects has something in it for telescopes of almost any size. It’s a a great example of the buried treasures waiting in the sky beyond the Messier list.
I have been on the East Coast for much of the last week and was still so time-shifted that I began to get tired about 12:30 am. I spent another hour or more looking at old favorites and a handful of new objects in less favorable reasons of the sky. As the Swan, Eagle, and summer milky way cleared the Easter horizon, it felt like summer had arrived in the Bay Area. Temperatures were sill in the 60s when I packed up and left about 2 am, and a large crowd of obsesrvers was still going strong on both Messier objects and other observing projects.
Nice night, and a nice beginning to the spring and summer observing season.