by Bob Czerwinski
When I arrived at Fremont Peak's Ranger Row, I wasn't certain about the prospects for a clear, dry evening. About 40-percent of the sky was covered with that dreaded high-stuff, and off to the west was an ominous band of very dark clouds. Numerous contrails were visible throughout the sky, many stretching from horizon to horizon. Temperature and humidity were initially a matched pair: 63F/63%. With all that visible moisture, I started wondering if I hadn't made a serious error in judgment, and really should have joined up with the TAC-SAC crew for a Blue Canyon evening. Well, by then it was waaaay too late, so I set up my 18" Starmaster and waited for darkness. I was soon joined by Craig & Elena Scull, who brought along their massive D&G refractor. Shortly thereafter Jamie Dillon arrived with his 11" Newt/Dob, rounding out the night's Ranger's Row crew. Peter Natscher was also in the general vicinity, and had set up his 20" Starmaster at the east end of Coulter Row. Approaching sunset, 75-percent of the sky was covered by various types of clouds, so all we could do was wait and hope. Not too long after sunset, with the clouds indeed dissipating, Ranger C.L. came over to greet the Ranger's Row gang. After chitchatting with us for a few minutes, and mentioning how nice the previous evening had been <grin>, C.L. retired to his residence for the evening.
Despite the moisture issues, which certainly affected the early-evening transparency in selected sky areas, the seeing was quite good last night. Castor was an easy split, and the E&F stars of Orion's Trapezium were easily visible all evening long. On a scale of one to five, I'd rate the seeing a 4.5, with long moments of extreme clarity.
My intent for the night was to get back to my H2500 hunt in Leo, but a substantial amount of moisture to the east made that an early-evening lesson in futility. So I just spent the first part of the evening viewing various showcase items, to include Jupiter and Saturn. Both giants were very impressive last night, with an enormous amount of detail visible throughout Jupiter's equatorial regions. Saturn's rings were as crisp and clear as I've ever seen them, with the A-Ring's dark broadening (the Encke minima?) very evident, and the gap (the Encke Division?) at the outer edge of the A-Ring popping in from time to time (323x - 7mm Nagler w/Paracorr). Despite the fine conditions, I couldn't spot Mimas, and had to settle for a seven-moon Saturn.
Not that I want to steal his thunder, but an early thrill came when Jamie showed us 4th-magnitude 40 Eridani (aka Keid or Omicron-2 Eridani). 40 Eridani has a companion star, 40 Eridani B, a white dwarf, sitting just over an arc-minute away at magnitude 9.6. Better yet, this white dwarf has a companion itself, 40 Eridani C, a red dwarf (!), sitting 9-arcsec away at magnitude 11. What a cool triple-star system! *Very* easy to see in Jamie's 'scope, too. Jamie pointed out that 40 Eridani B was the first white dwarf to be discovered, and noted the unusual nature of finding both a white dwarf and a red dwarf paired together in the same system. If you haven't seen the 40 Eridani A/B/C system, definitely check it out!
By 7:00pm the temperature had dropped to about 50F while the humidity has risen to about 85%. By 7:50pm the temperature was still holding around 48F, but the humidity had risen to 94%. Although it was difficult to see, ground fog appeared to have formed in the valley to the SE of Ranger Row, and also appeared to be rising. In ironic fashion, the overall sky transparency was definitely improving, with most areas of the sky free from cloud cover. Save for my primary, secondary and eyepiece, everything around me was extremely wet, and we were all complaining about the conditions. Taking a break from my showcase stuff, at 8:00pm Jamie and I wandered up past the observatory to see if we could spot Canopus due south. Jim Bartolini and I had attempted this viewing two weeks earlier, but without success. This time, scanning with binos, Canopus was pretty easy to spot. Nekked-eye, however, Canopus was barely discernable on the horizon, twinkling in the haze, sitting just above the lights of Gonzales, and probably within a half-degree of sinking into the western coastal range. Without the binocular siting, I probably would have missed the star.
Following our success with Canopus, Jamie and I wondered over to check on Peter Natscher, who was entertaining a group of overnighters with bino'd-views of Jupiter through his 20" Starmaster. Through Peter's 'scope, the detail on Jupiter was just outstanding, with the GRS just having rotated into view. Coulter's humidity, by the way, was noticeably lower than that of Ranger's Row.
About a half-hour after wandering back to Ranger's Row, a very light breeze started to flow and the humidity started to drop. In relatively short order, the humidity was unbelievably back into the 60% range, and all our gear started drying out. All sign of the valley ground fog completely vanished. From time to time, long, sharply-defined contrails were still visible overhead, but with the sky quite clear immediately to either side of them. The Milky Way, from the border of Gemini/Orion south through Puppis, developed that granulated sugar appearance, and by 10:30pm, the temperature/humidity was 46F/48%. How quickly things can change at the Peak!
It wasn't long before I (finally!) hit Leo ... and immediately ran into a problem: NGC 3645. According to TheSky, the Dryer description is: "Pretty bright, small, extended, brighter middle." Hopping a few fields from Sigma Leonis, I quickly located nearby "big n' bright" NGC 3640, paired with much fainter 3641. 3630 (also pretty bright, although considerably smaller than 3640) sits in the same field, so field orientation was very easy. Rotating TheSky to match my eyepiece view, I identified the location for 3645, along with nearby 3643. 3643, while very faint, was pretty easy to spot next to a 13th mag star. 3645, which TheSky lists as mag 14.2, should just have been a few arcmins away, but I couldn't find it. 3644, also in the field, was pretty faint, but I didn't have any trouble spotting it. So what's my trouble with "pretty bright" 3645? Jamie looked it up in his Uranometria 2000 (Vol 3) Deep Sky Field Guide, which puts 3645's location close to where TheSky sets it, but describes it as: "Stellar; a faint, small anonymous galaxy..." Okay, something is obviously wrong here; the two descriptions aren't even close. Personally, I think this is another misidentification problem with TheSky, with something possibly wrong in U2000, too. Still, at 251x (9mm Nagler w/Paracorr), I thought I would have been able to spot a "stellar" item. Is 3645 just extremely tiny and dim, and did I just miss this thing? Has anybody else logged NGC 3645 before?
I spent the next couple of hours in Leo, with no further identification problems (well, nothing major), calling it quits just after Moonrise. My last view of the evening was of NGC 4565, as beautiful as ever. After a bit of socializing, and just before heading back down San Juan Canyon Rd., my last check of temperature/humidity was 41F/41%.
So despite the early-evening conditions, it turned out to be a fine night at Fremont Peak.