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A Dream Night in the Observatory: The Moon

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“When you love something,
You have the capacity to
Bore everyone about ‘why’
-it doesn’t matter why”
-John Irving

I always enjoy getting to the observatory ahead of time. I like observing in the evening to early morning and, I like getting up early to observe as long as I have some significant observing time before dawn. On this morning I awoke before the alarm had a chance to disturb me. I made it up early. If I get up on time I am just fine, but to get up early is a real treat. Extra time to observe! The coffee tasted good this morning, my favorite, Choc Full a’ Nuts. I stepped outside the kitchen door and it was a beautiful, clear night. The temperature was in the low 70’s and felt nice. As I drove up Observatory Hill I could see the brilliant waning gibbous phase Moon dominating the landscape and the sky above. Silvery light filled the pastures. Dark hay bales were silhouetted against the ghostly hue. I parked to the north of the observatory. Anything I needed would be directly behind me in the backseat. I grabbed my light jacket and a couple of moon books, Rukl’s Atlas of the Moon and the Times Atlas of the Moon. My observatory has a roll-off roof. The four chains, hooked to the roof to hold it in place, are easily unfastened and I am able to push the roof back with a long pole.

With the roof open, I take a quiet look up at the two big TMB refractors, 8” and 10” F/9 apos. My love for apochromatic refractors began, like many, with Astro-Physics. My first Astro-Physics apo was a 6” F/12 Superplanetary. For someone who thought refractors were pretty nice, particularly after using an 8” F/13 doublet (R.E. Brandt lens) for a few years, an apochromatic triplet seemed like perfection. I have been in love with them ever since and, as time has passed, I have collected and used as many as possible! I have an AP 9” F/15 apo Roland built for me in a folded OTA. It is a wonderful telescope and I have had superb views with it. But, the fact is, the scope has been limited by poor seeing because of its location. It is housed in an observatory over my kitchen, surrounded by numerous heating/AC units, buildings, even an asphalt parking lot! Seeing is far better, or at least good-excellent seeing is far more likely to occur, at the farm.

I aimed the TMB 8” F/9 at the Moon. I am thrilled with the performance of this telescope. It is my only apo above 6” aperture that is in a straight-through OTA. Both my AP 9” F/15 and TMB 10” F/9 have a folded OTA. I focus in with a wide field eyepiece that shows the entire Moon, floating in space, bright – but beautiful! I try a few filters to dim the glare. The view is impressive. I switch to the Baader Binoviewer with 2x Barcon and Zeiss diagonal. I use the Barcon to increase the length of the light path which I need because the extension is in place. I would take it off and not use the Barcon but I know I will be imaging before long with the 8”using a 3X Barlow and I’ll need the extension. I will be observing visually with the TMB 10”. I put two TMB 16mm SM eyepieces into the binoviewer (239x) and the view is astonishing! I can see sunset on Clavius, the Straight Wall and that magnificent trio, Ptolemaeus, Alphonsus, and Arachel. Looks like Triesnecker and its intricate rille system is right on the terminator. For several minutes I just sit back and observe. The views are spectacular and crisp. The seeing is good, very good, 8/10, with extended periods of 9/10. I am ecstatic!

I then set up the laptop and Philips Toucam Pro. I use K3 tools to capture an AVI then, Registax for stacking and enhancing multiple images (with usually just a touch of Photoshop). I use a 3x Barlow and will often remove the diagonal to image straight through (although not always). Using the 3x Barlow with the extension on the telescope, I usually image for 180 seconds so I’ll have time to look with the 10” while imaging through the 8”. I also am not imaging non-stop so I can just sit and observe with the 10” as well. And, that’s what I like to discuss, observing the Moon visually with my TMB 10” F/9 apochromatic refractor.

Starting with 10mm TMB SM’s (228x) the lunar surface looks very nice, but I can see that, on this night, seeing looks like it will allow significantly higher magnification. Trying to describe the view of the Moon with a 10” apo collimated perfectly, and of the highest optical quality, on a night of superb seeing may be impossible. In fact, I think it is impossible. I will do my best but I don’t think I am experienced enough, certainly I am no expert. I am comfortably seated, seatbelt fastened and at the controls of my own spaceship hovering over the surface of the Moon viewing incredible detail closing in, then, backing off a little, finally going in for a close-up. There is, of course, some turbulence, I can’t say I have ever observed with no turbulence at all, but, tonight the turbulence seems slow and rolling and detail is preserved. As someone who has spent time at the eyepiece drawing detail on the Moon, I can see that the fine detail present is not only astonishing but could not be drawn, not by me. I truly feel I have been granted some special wish.

The Straight Wall and Rima Birt immediately catch my eye. Using the slow motion controls on the AP 1200 QMD mount I center them. Rupes Recta, the Straight Wall, is a large fault. The setting sun has the scarp glowing brightly. I can see the disconnect in the northern half easily. Craterlets abound in staggering numbers, especially as you move from Rupes Recta east around Thebit . Birt, of course, is filled with shadow and Rima Birt is spectacular. The dome(s) at its N end are nicely seen, their low swelling just set off by the late, setting sun, I pull out my Times Atlas. I am astonished. The tiniest craterlets flick in, then out, of view. Not only is the view so spectacular because of the incredible amount of detail, but also because of the crispness of the image. The view is beautiful and in focus right up to the edge of the FOV. How could I ever have any desire to see any more detail than this I wonder? I just sit and look. There is tremendous detail, detail as good, or better than I remember ever hoping to see. The long shadows merge into the terminator with the floor of Purbach still visible and its beautifully shining walls surrounded by the deep, pitch black of Lunar night.

When I am observing the Moon on a night like this my mind wanders back to great observers primarily from the 19th and early 20th century; Beer with his small Fraunhoffer refractor, Lohrmann, and Krieger. James Nasmyth started a ghost story by walking around at night with his white telescope tube. Elger used an 8 “ reflector and once wrote in his logbook that his fingers were so cold while observing the Moon that he could hardly hold his pen. Goodacre produced a magnificent 70 inch map which was reproduced on a smaller scale in Hutchinson’s Splendour of the Heavens. No lunar map is as beautiful as Schmidt’s while Fauth’s map contains incredible detail. But, I am not limited to the 19th C. as observers from the 20th C., Alika Herring, Kenneth Abineri, and Harold Hill come to mind as well. I remember seeing a drawing of Posidinius by Herring that truly inspired me. Because of Herring, Posidonius is special to me and I have drawn Posidonius a number of times with many different telescopes.

As I continue to wander of the surface of the Moon I come upon Alphonsus. The detail I am seeing reminds me of the image of Alphonsus from Ranger 9 taken a few minutes from impact. The bright central peak was once thought (no longer) to be the site of mysterious red glows. Here, I must admit, I think about red glows, obscurations and lunar change. Certainly no one can predict an impact that might be visible, or a landslide of material down a crater wall. Could a lava tube collapse and a new rille form? Lunar domes are most certainly volcanic. Of course all active volcanism ended long ago, but I think about it. In this way I may be more like my 19th C. counterparts. I do study the Modern Moon (a great lunar book by Chuck Wood). But, I can’t put away all those wonderful old observations, thoughts and writings about TLPs, obscurations and red glows. I wouldn’t want to. As I observe the fine detail continues to demand my attention. Why do I love to observe finer and finer detail? Why does it matter if I can see that tiny little craterlet or rille? I love it and, as Irving said, “It doesn’t matter why”. The only way to see detail any better than this is with a significantly larger scope and similar seeing or, to fly there yourself!

Rimae Alphonsus is visible and craterlets are sprinkled across the floor. Other delicate rilles pop in and out of view. Dark patches, within which are tiny craterlets, surely are the result of volcanic out venting. I’m still looking out for red glows as I pass on to Ptolemaeus, a great crater, the floor of which is lava filled, and, has amazing saucer-shaped depressions. Are they lava filled craters? Some type of sink structure? I don’t know but cannot recall similar features elsewhere on the Moon. Tiny craterlets are again sprinkled across the floor. I pull out my Times Atlas and compare. The seeing is 9/10 and I am having the time of my life! Based on the number of craterlets inside the most prominent saucer shaped depression, Ammonius, I am seeing at or near the threshold of the Times Atlas of the Moon!

Looking around I see by the change in the position of the Moon I have been observing for a long time. I decide to take a break. There is some coffee in the thermos that tastes good, very good. I spend some time checking on the images with the 8”. Looking at the AVI’s I have a good feeling about them. It appears I should get a few nice images after the processing. It takes 45 minutes to one hour to take the AVI, process it with Registax, and end up with a final image.

Walking outside of the observatory there is no sign of dawn. I finish up the coffee, stretch and decide I’m wasting time. The seeing is just too good to be anywhere except at the eyepiece. I set up the 8” for another AVI then move over to the 10”. I’m using the 6mm TMB Super Monocentrics and, at 381X, I remind myself that the seeing is not always this good. HA! It is only rarely this good! For fun I slip in the 5mm TMB’s (457X) and the image holds. Backing off in magnification I move a bit west and come across Davy, and what looks like machine gun fire impacts (to quote Chuck Wood), Catena Davy. I wonder, if I were sitting at the eyepiece when the impact occurred, what would the view have been like? Would the bright impacts have hurt my eyes? If you could have looked at it directly I’m certain the view would have been spectacular.

I’m day dreaming again. That’s a big part of it. Sitting at the eyepiece of a beautiful refractor, excellent seeing, wandering over the lunar surface, dreaming. But, I don’t think only about the distant past. I know that I will soon be passing over Montes Apenninius to Hadley Rille (Rima Hadley), site of the Aollo 15 landing. But, first, I decide to explore Triesnecker and its intricate rille system. Triesnecker itself is filled with shadow. Because of the low sun, the rilles seem even more prominent than normal. I don’t quite understand everything about the formation of all these beautiful lunar features. That’s why I do not only think of the past. I also try to understand what planetary geologists or, as I prefer to think of them, selenologists, think. I know that some rilles, like Hadley Rille, represent the remains of rivers of lava, perhaps collapsed lava tubes. My family saw a lava tube on a trip to Hawaii once. My claustrophobia will not allow me the treat of actually visiting one, at least not inside one that is intact! Looking at the crisscrossing spider web of delicate rilles around Triesnecker I’m not sure of their exact origin. I think they are cracks in the surface of the lava filled terrain. I’ll look it up, but tonight (or should I say this morning) I just enjoy the view. The rilles are right on the terminator, merging into the night. I pause for a while, changing eyepieces, moving in for a high magnification view before moving on.

The sky is now beginning to brighten significantly in the east. I hurry on to the Apollo 15 landing site and Hadley Rille. Hadley Rille winds along just southwest of Mons Hadley. It looks like, even with all the shadows present, the exact landing site is visible. July 30, 1971, when Apollo 15 touched down, seems long ago now. But, I have no trouble recalling the excitement that I, as a teenager and young man, felt during the entire “Race to the Moon” from Ranger and Surveyor, Mercury, Gemini and, of course, Apollo. It seems an extraordinary feat to have landed that spider- legged spacecraft in that exact location, but the entire manned space adventure, from earth orbital flight to landing upon the surface of the Moon, then, safely returning home, was filled with extraordinary feats by all involved. It’s sad that it was just a race to the Moon and not the start of a larger adventure. But I am glad that I was there to experience the excitement.

Although the sun is still below the horizon all but the brightest stars are now invisible as the sky lightens up. I take a few moments to observe sunset on the Alpine Valley now nearly completely in shadow and then, Plato. I am able to clearly make out several craterlets on the floor of Plato and as this observing session comes to a close, I’m beginning to tire and, I don’t try to see more. Slipping in the 10mm TMB eyepieces (228x) I scan the terminator one last time. I’ve captured a number of AVIs of the lunar surface with my TMB 8” F/9. But, no matter how good the images with the 8”,this night, a dream night of observing, will be remembered most for the outstanding views of the lunar surface I had through the eyepiece of my TMB 10” F/9 apo.


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