Log, Jul 27, 2001

84 visitors. The temperature started out about 70 degrees, falling to the low 50's by dawn. What would turn out to be a rewarding, but most unusual night at FDO started with high expectations. The air was dry, and clear skies were promised for the entire night. By 7:30 PM Les Coleman, Steve Brandt and Doug Stewart had met at the dome and begun preparations for the night, joined shortly thereafter by Joe Hartley and Art Guarino. The skies were about 95% clear as twilight began and crowds began to arrive for the evening's first viewing.

First up was the moon, slightly past first quarter. Always a fine sight in even the smallest scopes, the 16" revealed intricate detail along the terminator, with many craters large enough to hold the whole state of Rhode Island. For plenty of young and old alike this was their first view of the moon in a large telescope, and all were impressed, to say the least. The line extended out of the dome and nearly to the gate, where Les and Art conducted impromptu talks about numerous topics. Les showed the moon (and Mars) to folks in his 4.1" Astroscan, while they waited to get into the dome, and these views provided an instructive contrast to what they would soon see in the big scope.

As just about everyone finished viewing the moon, a call went up from the crowd to go to Mars. As Joe obliged, and started to move the scope, a round of applause rang out in the dome - this is what most people REALLY wanted to see! Doug and Steve had brought images from the Mars Global Surveyor, showing folks the progress of the great dust storm that now completely encircles the red planet. Les explained to the visitors that this would almost completely obliterate our views of any surface detail, but the crowd remained undaunted. We were able to view the northern and southern ice caps (about 80% of the visitors could see these), but there was nothing else but pale orange haze. Still, most visitors were happy to get their first good look at Mars, which has now receded (at about 5 miles per second) 50 million miles from Earth (it was 42 million at closest approach last month).

After showing Mars to all in attendance we decided to swing the scope over to Comet Linear, which had recently crossed into Vulpecula. It was still visible easily in binoculars, probably about mag. 6 or 6.2, but is fading noticeably with each passing day. Just as Joe prepared to slew the scope he noted that the power to the 16" scope had failed! "What now?" the staff thought, as we've been plagued by a number of electrical gremlins in recent weeks. A quick inspection revealed that the AC adapter that drives the scope had apparently failed - for no obvious reason. But the indefatigable Joe (who serves as our technical director for good reason) was not about to throw in the viewing towel for the night! He removed the adapter and took the DC power from the converter used to power the CCD camera. It's lower in voltage, but it worked. Meanwhile, as Les examined the failed unit with a voltmeter, it inexplicably sprang back to life - ah the mystery of electronics! We continued our viewing for a time using the other unit (adequate) but realized we'd need to do a proper realignment if we wanted decent pointing accuracy. So back onto the scope went the now resuscitated original pack, and we proceeded through the rest of the night without incident - not at all sure what had caused the original failure. It may have been something as simple as a loosened connection at one end of the power pack. Perhaps a fussy thermistor. Time will tell.

Our targets for the rest of the evening ranged from the relatively nearby Comet Linear (44 million miles distant) to numerous galaxies, lying millions of light years away. To aid in comparing things the notes below are grouped by object type, rather than in viewing sequence.

Planets: We observed Neptune, Uranus, and Saturn - in that order. Neptune is now easily found in binoculars jus 15' SW of Upsilon Capricorni. At mag. 7.8 and 2.3" in diameter, its quite bluish disk was just discernible in one visitor's 80mm short tube refractor. In the 16" at 340X the disk is still quite small, but just south of the planet we were able to see Neptune's only large moon Triton. Uranus, just east of the star 44 Cap., was seen by several folks with the naked eye - the first time Doug could recall doing this. A tribute to FDO's dark sky! We could spot just two of Uranus' moons tonight - Titania and Oberon. Ariel and Umbriel were too close to the planet's mag. 5.7 glare. Later in the night as Saturn rose we got a nice view of the rings (now even more open to our line of sight than last year) and five of its moons. One visitor, Keith from Providence, came late and stayed all night to see Saturn - this was his first view of it in anything larger than a 60mm refractor - so you can imagine his pleasure! During moments of steadiness we could even spot the elusive crepe ring.

Late in the evening we had a visitor arrive from the Boston area, Lew Gramer. Lew is a very active meteor observer, and he drove the two hours down to FDO's dark location to enjoy several smaller showers that are near their peak at this time, notably the Alpha Capricornids and the Delta Aquarids. Lew works closely with N.A.M.N., the North American Meteor Network, a group of dedicated observers around the country who share their observations and keep the rest of the astro community up to date on upcoming showers. After moonset at 12:32 AM, Lew got down to some serious observing, joined by Joe, Les and some of our other visitors. Many WOWS! and OOHHS were heard reverberating throughout Ninigret Park as some fairly intense mini-peaks were enjoyed by all!

Globular Clusters - these always popular objects get plenty of scope time each clear night. Tonight we observed globulars ranging from the remote and dim NGC7006 in Delphinus (no resolution, just a puff ball) all the way up to the giant showpieces M13 and M2. In between came NCG 6934 in Delphinus (rather good actually, though small), M30 in Capricornus (a very nice globular, with a regal crown of stars radiating from its upper half), and M72, also in Capricornus (dim, unimpressive, but fairly well resolved). We had some spectacular views of M13 and M2 at 340X - just breathtaking, and not to be missed! Nearby M13 we noted the dim galaxy NGC6207, visible in the same low power field as the majestic globular. Several times during the night we also observed the fine M15 in Pegasus, with its bright and extremely concentrated core.

Nebulae - around the middle of the evening a bank of pesky high clouds began to cover up the southern half of the sky, making our viewing prospects rather poor. This happened at the same time the power failed to the scope - so things were not looking good! However, the skies cleared again just before moonset, and our spirits all soared accordingly! Back into view came Sagittarius, with its showpiece nebulae M17, M8 and M20 - all discussed in detail in recent logs. These objects were now dipping toward the SW horizon, but the Oxygen III filter still uncovered most of their glory!

Double stars - not many of these were observed this night, as too many deep sky objects beckoned. We did examine Zeta Herc. (not resolved) along with Delta Herc. and Mu Herc. - both wide and easy pairs. The most noteworthy double, however, was the fairly close pair HD 200724, just along side of Comet Linear. The two stars, mag. 8.5 and 10.1 are separated by 4.9" - a nice sight against the hazy glow of the comet's core.

Planetary Nebulae (PN, for short) - Very few objects in the heavens (other than the planets and many stars themselves) show any color at all. Most are either white or gray. However, many PN radiate strongly in the green or blue area of the visible spectrum, and their color can be quite stunning - especially in larger scopes that have the light grasp to intensify these colors (One of the reasons we have trouble seeing color in space is that the human eye is very insensitive to color at low levels.) The past two weeks we have enjoyed the fine PN NGC6572 in Ophiuchus - one of the bluest of them all. Very bright and intensely colored in the 16". Doug noted that in his 8" SCT this color, although noticeable, is not nearly as pronounced, as that scope has just 1/4 the light grasp of the 16". We looked for, but did not find, the large and faint PN PK 47-4.1. It is located in a very rich Milky Way star field, making the exact position difficult to pin down quickly. We decided to try again on a night when we have more time to examine the area and to employ our Oxy-III and other nebular filters. Some other smaller, but bright PN were also enjoyed. NGC6891 in Aquila is about 10" across with a bright circular central region surrounded by a fainter hazy outer shell. It looked very good at high powers, even appearing well detailed at 603X! Three other PN were observed, NGC6879, NGC6803 and 6804 - all small, round and not especially interesting.

The most rewarding sight for the night was the large and fairly dim PN NGC246 in Cetus. (See the photo on page 651 of Burnham's, Vol. 1) Doug and Joe had been spot checking galaxies in Cetus on SkyMap Pro when we decided to put this PN in the scope. At first (no filter) it was almost invisible - but just recognizable enough that Joe remembered it from last fall's observing. He inserted the Oxy-III filter and the nebula snapped into vivid view! A large ghost of a thing, much brighter on the left (western) half and edge, fading as you move east. Still, using averted vision and relaxing one's eye, the whole circle steadily filled with eerie light, showing even more detail than in the photograph! This one will be revisited many times on dark nights ahead! Doug doubted that he would be able to see much of anything in his 8" SCT, but will give it a try at home for comparison purposes.

Another favorite showpiece at FDO is NGC7009, the famous "Saturn Nebula" in Aquarius, Large, bright, and very blue in the 16", this night we saw the "rings" - two faint extensions of gas on either side of the main nebula - more clearly than anyone could recall. Very crisp at 340X, and one we will revisit many times!

Galaxies - regular visitors to FDO know that we don't spend a lot of time on galaxies, at least not when the general public is on hand. This is because even in a 16" scope most of them just don't look like very much to the inexperienced eye. But give us a moonless sky, a darkened dome, and a little time, and galaxy hunting becomes very popular, especially with the "old hands". (Joe's favorite objects!)

The late crowd and a 12:32 moonset meant that the galaxies had to wait for a while - and had to compete with Lew Gramer's meteor show out on the lawn! But we managed to "bag" a fair number of the faint fuzzies. NGC7332 and 7339 in Pegasus, mags 11 and 12, were an easy sight in the same 25mm eyepiece - both clearly spiral shaped. Fornax and Sculptor were rising in the SE, and experienced observers know that these constellations provide great galaxy hunting - if only they weren't all so far south! Despite the low position so early in the year, Joe and Doug revisited two old friends, NGC247 in Cetus and NGC253 in Sculptor. Both are huge in area, and therefor have fairly low surface brightnesses, especially NGC247. However, NGC253 is the fourth brightest galaxy visible from our latitude, at magnitude 7.2. It's huge 25' x 7' size, though, means that the contrast against the sky is not great - very much like M33 in Triangulum. But on a dark night and with the galaxy near the meridian it does reveal amazing detail in the 16" scope. Can't wait for the fall! We wrapped up our galaxy viewing in Cetus with the string of bright targets: NGC584, NGC596, NGC600 and 615. All fairly bright, and not difficult.

As dawn's early light approached Lew Gramer asked if we might check out a favorite galaxy cluster of his: Pegasus 1. This grouping is anchored by NGC7619, and within one field of view (40 mm Konig) lie no fewer than 10 galaxies! None are bright, several are very faint, but on a dark night we should be able to see at least 8 of them in the 16" - only 5 could be seen this night in the building twilight - more fun lies ahead!

Finally, it was just getting too light to do any serious observing, so Joe and Doug (and visitor Keith - thanks for the help, Keith!) began to close things up for the night. As they left the park at 4:40 AM, Saturn, Venus and Jupiter sparkled in the eastern sky - a harbinger of many fine nights to come at FDO!

-Les Coleman

Leslie Coleman
Leslie Coleman
Entry Date:
Jul 27, 2001
Published Under:
Leslie Coleman's Log
Subscribe to Leslie Coleman's Log RSS Feed