Old friends I never met before
It’s a great night that begins with Pal 2 in Auriga and ends with Pal 8 in Sagittarius, and includes six new sightings along the way. February dark moon is the only time I can do that from my Southern Hemisphere site. This year was the first time I’d ever tried this unusual latitudinal pairing, and what’s more, five nights in a row. Add to it the juxtaposition of NGC 288 and M22 and this dark site visit goes into the Book of Improbable Pairings. I would have never considered this sequence before, but on this site visit I had just received a brand-new Matthias Wirth/Intes MN86 Mak-Newt from Markus Ludes in Germany and I wanted to pedal-to-the-metal with this beauty and see what it could do. And . . . in that paradisal dream of all stargazers, the sky was 8+/8+ for nine straight nights, shirtsleeves all the way. Mozzies courtesy of a frog pond 10 meters away, mozzie repellant courtesy of the local drug store.
Markus Ludes and his master fabricator/optician Matthias Wirth have come to the rescue of Intes at a tough time in its history. It lost its US distributor and its homeland Russian builds are now available only though German and British dealers. Intes has gone through management changes and varying product badge names over the years, but all the while the opticians upheld their reputation for the finest Maksutov optics one can buy at retail. Alas, their mechanical acumen hasn’t always been as refined as their optical figures. Of the six I’ve owned, two were damaged in shipping for the same reason: the meniscus retention system was inadequate—pathetic is the better word for it given the trail of glass shards Intes meniscus retainers have left in their wake. In one case a thin sheet metal retainer clip on an MK67 sheared off completely, leaving the corrector/secondary assembly to wobble its way up and down the tube. Luckily nothing shattered and a good clean-up put the scope back to rights. In my MK66 the retainer was three round metal washers that had been ground flat on one side to fit into the tube. As an optics retention design it was blockheaded at best. The designers apparently never thought of what could happen if the screws holding the washers came loose. Mine did, on an OTA shipped to me in a textbook-perfect packing job. One loose screw and a washer rotated just enough to let the meniscus slide out from under the other two. There are few sounds more apocalyptic than picking up a beautifully packed box and hearing the telltale crinkle & grit of a meniscus wobbling its way up and down the tube, mangling both itself and the baffle tubes at every jolt. I managed to salvage both scopes and restore their optics to their pinpoint star images (Intes is Intes, let edge chips go hang), but the cosmetics were so awful that I couldn’t bring myself to sell them. I gave one to a beginner just getting started and kept the other as a loaner for friends temporarily without.
So before buying an APM re-tube of optics bought from Intes, I asked Markus Ludes how the optics were mounted. “We’re not so stupid as Intes,” came Markus’s tart reply, and he attached six pictures of his OTA craftsmanship to prove it. When the OTA arrived at the local South African post office, it took three of the staff to bring it out from the back room and put it in my pickup. They marveled that this was the biggest box they had ever handled. “Do you actually look through these things,” one asked, “Don’t your arms get tired?”
How do you tell a non-astronomer about the glories of perfect fit & finish? That a 1/10th wave optical figure produces pinpoints so tiny that even at the highest power I had available (212x or 26.5 per inch) I could not detect a diffraction ring. Pinpoint stayed pinpoint no matter what eyepiece was in there. All Airy, no ring. The star point is unmistakably sharper than my Santel seven-inch f/10 and Intes 715 Maks figured to 1/6th wave. The APM OTA is as comely as the meniscus rings: purposeful, durable, svelte, beautiful. (That’s not to say my wife is willing to let me install it as an industrial art sculpture in the living room.)
My dark site is D - A - R - K. Arid semi-desert and 4800 ft. altitude. It resembles New Mexico and Arizona high desert table land, and for the same geological reasons: ancient seabed whose only travails across their millions of years have been wind and rain. As luck would have it, I arrived the day after a large storm had turned the skies to crystal and the dirt roads to goo. I slithered as much as steered the last 13 km. Weltevreden Farm is a 60,000 acre sheep ranch so remote there are no human-made light visible anywhere. The nearest town that merits the name is 67 km away. The name “Weltevreden” means “well satisfied” in Afrikaans. I’ll take this over harps & halos any day.
First light was the GC
NGC 2808, a summer test object for seeing and transparency. It is a massive, dense globular 31,300 ly away in Carina/Volans. At
Mv = 6.2 It has only 23 red giants between mag 14 and 15 (corrected for 0.2 mag reddening) and its central luminosity density
muV is mag 15.08. The term “central luminosity density” has a technical definition for professionals, but the practical meaning for we visual types is that
muV approximates the average visual magnitude of stars across the central core. If you think you’re seeing a GC’s core stars, look up
muV in the Harris Catalog. Up north the only Some other globulars with NGC 2808’s specs are M80 (NGC 6093) = 32,600 ly,
Mv = 7.33,
muV = 15.11; NGC 6293 = 31,000 ly,
Mv 8.2,
muV = 15.72; NGC 6388 = 32,300 ly,
Mv = 6.3,
muV = 14.49; and M56 (N6779) = 30,600 ly,
Mv = 8.3,
muV = 18.01. You might give these a whirl to see if they accurately portray your own seeing conditions for the night. In my 7-inch scopes N2808 has never really resolved; granularity was the best a good night could do. One look in the Wirth-Intes Mak-Newt and POW! To quote the famous Arthur C. Clark line, “My God, it’s full of stars!” At that, I was all but ready to light incense and candles in front of Goebenstrasse 35, Saarbrücken, Germany. If I go to heaven, can it please be NGC 2808?
