Special Observing ReportSCAC Bonny Doon Star Party: 5/11/02
A late wake up Saturday afternoon, and leisurely hour of coffee and bagels at a Boulder Creek cafe soon led to a harried two hours documenting our (theAstronomer - "T" and I) trip to the Fremont Peak Observer Association (FPOA) Observatory. With events passably captured by 3:00pm, T and I immediately setoff for points south to the Orion B&T store and warehouse in Watsonville. Have cash... will spend.
For you see, astro.geekjoy's latest member, "Vicki" (a Vixen Optical HD102 achromatic refractor) needed a ride for the SCAC Saturday evening star party. And T and I were going to pick up a new SkyView Deluxe mount. The hope was to setup Vicki and give the scope a first light opportunity under the fine skies of the Santa Cruz Astronomy Club's (SCAC) Bonny Doon Observing Site.
By 7:00 that same evening, T and I had our act together well enough to make the twelve mile drive up from Boulder Creek to the observing site. We arrived just after sunset and soon had Vicki and the Pup on their respective mounts. Venus and Jupiter were already visible even as respective eyepieces were dropped into diagonals. All spread out above the western horizon, the classical planets would be the first order of the evening...
All first lights pose difficulties. On this particular evening Vicki encountered two. For SCAC club member Ralf and I immediately identified problems with fastener threads on the scope's tube rings. The normal fasteners were worn and the alternatives were too shallow to properly accept the thumbwheel fasteners from the mount head. A little ingenuity soon had the OTA securely mounted - with a little assist from a young associate who found some "shimming" material - twigs.
The second problem followed from the type of inch and a quarter adapter found on the focuser. This particular adapter was a wee bit too long for the combination of diagonal and 35mm eyepiece to achieve focus. However, it was soon found that other eyepieces - 25mm Ultrascopics and smaller did fine.
Although Vicki has been here since T's arrival Wednesday, I had yet to look through the scope. Meanwhile fellow SCAC and AstroTalk member Dan would soon arrive with his superb FS102 Takahashi apochromat. And thus Vicki was about to be weighed in the balance. Would the 1000mm focal length, 102mm achromat prove to be the fine instrument needed to kick off Astro.Geekjoy's first fundraiser? Or would I end up spending the next several months carefully respacing doublets, and aligning objectives in order to achieve barely passable views of Moon, planets and double stars? Would Vicki's performance be more akin to that of the ST80 Pup or, like Dan's Takahashi, rise toward the level of 150mm MCT Argo?
These were some of the questions that would be answered this very evening - should sky prove supportive.
From that very first view of Venus, T and I knew that Vicki's focused images were delightfully low on chromatic aberration. This was one nicely set up collection of crown and flint glass! Sweeping the scope further east, Jupiter was quickly acquired. At some 200X, all the various belts and zones normally seen through 150mm Argo under decent seeing were possible. Would the image of the "Banded One" pass muster with that provided by Dan's nearby and now fully operational "deathscope"?
That first view through Dan's Tak caused me some consternation - until I realized that he had selected his "star party magnification" of 120X. There was no way to make a fruitful comparison between Vicki and Taki with such a disparity in magnifications. So, Dan dropped in a barlow lens and ran the magnification up to something that more closely approximated Vicki's 200X. In so doing the gap closed considerably, but it also remained clear that Taki's florite-elemented 1/6+ wave optics gave a crisper presentation of the belts along with enhanced contrast and more natural color. So in this one area - observing the amateur's planet - Vicki was good, but Taki was excellent.
During the course of the evening, there was only one other area of observation on which the superb optics of the apochromat displayed a clear advantage over the achromat. This was seen while observing globular cluster M13 later in the evening. There was something tighter and more contrasty about the way the Tak showed the many 12th magnitude stars just inside the upper limit of direct perception. While star-chaining was possible with the Tak, Vicki made the effect less obvious.
Between views of Jupiter and that of the "Great Cluster" in Hercules, Dan and I turned up a number of other studies... Mostly double stars. Neither of the scopes could successfully resolve 1.3 arc second Iota Leonis. Such a close and disparate double would have placed the faint companion right on the primary's frontier. Interestingly, we looked up a second double of similar seperation, 1.3 arc second Gamma Virginis (Porrima). It was here that Vicki showed a clear advantage over the Tak. This was seen as an hourglass split of the two third magnitude components, whereas the Tak was only able to show a slight pinch in the waist between them. Dan and I speculated on why Vicki would have given a visibly superior resolve. We concluded that the airy disks of the two bright stars were actually smaller because luminosity had transfered out of the airy disk to the first diffraction ring of the 1/4 wave optics of the achromat. While the APO displayed larger airy disks (as evinced by the lesser luminosity of the diffraction rings).
Dan and I also dropped by 2.1 arc second Xi UMA and more northern Nu - a very difficult disparate. Xi showed nice wide separation at the roughly 300x magnification just used to attempt Porrima resolution. Meanwhile, Nu's 10th magnitude companion was more steadily held in the Tak but still remained visible in the Vixen. Nu by the way, is a pair that hangs right on the limits of Argo's resolution under the half magnitude less transparent skies seen from Backyard Boulder Creek. This truly argues the value of an unobstructed vision of the sky and all its' denizens.
Both scopes were turned on Epsilon Lyrae at different times throughout the evening. At 120X, Vicki's view was that of four tightly glowing balls of luminosity, well distinguished in gap of separation. Gorgeous. The real test was 6th magnitude Pi Aquilae, and here Vicki did not let us down. Again, two perfect little balls of light, well distinguished some 1.4 arc seconds in seperation.
However there were certain "failures" with a couple doubles during the course of the evening. Seeing conditions, though good, did not support resolutions of the difficult Antares and Delta Cygnii disparates. Confidence remains high however, that a future night of better seeing will make both companions plain.
"While the boys were busy trying to prove who had the best scope on the block, I struck up a conversation with SCAC member Ralf. His charming germanic accent and obvious love for astronomy made for great companionship. Conversation turned toward Comet Ikeya/Zhang, which Ralf had not seen yet. But that didn't last for long! Ralf fetched an excellent pair of binoculars from his truck, and we sat side by side in the fragrant grass looking up toward Hercules and Ursae Majoris. He was a bit unsure that he could find it, because the majority of his celestial navigation had been done with a "goto" telescope. It's funny how sometimes people can bond quickly and form a line of communication between each other, because within moments, I had Ralf navigating toward bright Ikeya/Zhang like a pro. As we laughed and talked with one another, I assured him the same methods would work quite wonderfully with deep sky objects. Since Jeff and Dan were still absorbed in their comparison studies, Ralf and I swiped the "Pup" and away we went. Within moments he found the M44... then the M67... the M81/82... the M65/66. Who needs "GoTo"? All it takes is a little effort for a lot of fun!"
As the sky drew darker, double star observing gave way to that of galaxies. Dan and I turned the four inchers on the M81/82 pairing. And both scopes gave fine, high contrast views. The real test was M81's neighboring irregular dwarf - NGC3077. This particular 10th magnitude galaxy often proves difficult to the 80mm Pup achromat and probably offers the greatest insight into differences of even a few additional millimeters of aperture. For you see, both four inchers revealed this faint, face-on irregular obvious to the eye, while the Pup placed more serious demands on the skill of the observer just to detect it.
About this time, the Virgo galaxy field culminated to the south. I turned both the Pup and Vicki on what is arguably the most difficult of the Messier galaxies to detect with any sense of definition - M98 west of 6 Coma Berenices. While the Pup, under these fine 6.0- ZULM conditions could just detect the edge-on as such under moderate aversion, the four incher made presentation direct to the eye. There is truly a world of difference between a three inch and a four inch scope when it comes to small galaxies and faint nebulae.
Speaking of sky conditions, Dan and I turned the four inchers on M44 to determine how difficult the 12.7 test star would be. At around 110X in magnification in each scope, the eye could hold the star direct about 50% of the time through the Tak, while the achromat only achieved this fleetingly. Assuming seeing stability of 8/10 at that time, the calculated limiting magnitude on this occasion was 5.8 - a fine sky indeed!
By 11:00PDST, Dan - Takky in tow - had departed (due to an early Sunday morning engagement). Meanwhile, T, SCAC/AstroTalk member Mark, and I turned up the M84/86 "Galaxy Field of Dreams" in our various scopes. Views were taken through the 80mm Pup, 4 inch Vicki and Mark's fine 12.5 inch dob. Guess who's scope turned up the most galaxies? The count? Five for the Pup, seven for Vicki and ten for the dob - with eagle-eyed T seeing a possible 11th. This is one remarkable field of galaxies. The two main Messiers - near twins, triangulating with a faint NGC edge-on (4388) with an even fainter face on (4387) in the triangles midst. Add to this a bright pair of face on NGC's (4435 & 4438) with 45 arc minutes to the east and a sprinkling of even fainter galaxies around the perimeter to the west.
Now there was in fact one other peculiarity about this particular night out under the stars. For you see, I had never before gone out to an observing site by sunset and observed continuously until the spread of "rosy-fingered dawn" made continued observation impossible. For you see, unlike the last three evenings of observing, a variety of circumstances had conspired to make such an "all-night stand" possible. For one it was clear. For another, it was steady. And most importantly - it was warm! Perhaps the finest and most comfortable night of deepsky experienced since things began to turn sour last autumn.
There were, of course, other factors. T's visit. Mark's night-long presence. Dan's optophilia. A new observing friend - Andrew - with his LX 50 200mm SCT. Old observing friends Ralf with his 10x50mm binoculars and Leon with Coulter 250 dob. The right night. The right equipment. The right company...
Now I hope I haven't given you the impression that this observing report is drawing to a close, but to be honest, I am going to have to knock off. But first a few bullets before running out the door to compare Jupe through Argo and Vicki:
M104: Sense of lane to me and others through Vicki. Obvious to T.
Comet IK: Both Dan and I turned this large bright "Herculean" comet up as M92 and despaired at its lack of resolution!
Omega Centauri: Best resolution seen yet. This time through Mark's supercollimated 12.5 inch dob and solid 5/10 low sky seeing stability.
Planetary NGC4361 in Corvus: Easily found. Vicky even showed the 13th magnitude central star on moderate aversion.
Ring Nebula: 13.1 star on mild to moderate aversion at roughly 120x with detectable ansae thinning.
Eagle Nebula: T showed Mark and I how to locate the "Pillars of Creation" above the "saucepan" of the nebula's associated open cluster. (T could in fact make the pillars out for brief interludes.)
And the superb view of obvious filamentary detail seen of the Eastern and Western Veil Nebulae as displayed through Mark's dob equipped with Ultrablock filter. What an incredible walk!
During the course of this one particular evening, we dropped in on the five classical planets, fifteen double stars, ten nebulae, fifteen globular clusters, twenty-four galaxies, and nine open clusters. (But whose counting...) None required reference to charts to find - guess you can teach some old astronomers, old tricks!
"But no tricks here... Only treats. Half the joy of observing with other veterans is the "Challenge". Pick a number and find the fuzzy. First one there gets choice of scope! Silliness? You bet... After such a fantasy night, it was good to just relax and let our hair down a bit. I kept hoping that Mark would wander away and leave that 12.5 unattended, because I have certainly missed "standing up on the job with the dob"! Bright random meteors flashed across the dawn as we challenged each other to different targets, laughing and hustling between scopes to see which could get there first. "Musical Scopes"! What a concept. But as for those "old astronomers"?
There ain't nothing like a new day..." ~T
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