Posts Made By: Thomas Dey

The perigee full Supermoon is tonight. I wanted to do SOMETHING related to observational astronomy and involving la luna. So I went out on the deck with a book and an observing chair, rising moon shining over my shoulder... and read some of it: "A Torch Kept Lit" ~Great Lives of the Twentieth Century~ [Eulogies by] William F. Buckley, Jr. edited by James Rosen. The font is ~10 pt. Times New Roman. On the plus side, Yes, I read the eulogy of Tom Hume (1928-2003) on pp. 250-253. On the minus side, I will have to wait 'till Y2034 to read the eulogy of Nan Kempner. Speaking of eulogies... Tom Dey (1947-<2034?) ~RIP~

I'll bet many are curious about those Edmund Astroscans that came out 1976 and was produced thru Y2013. The 4+ inch f/4.2, "red ball" telescope . I just got one used here to examine it and try to understand the mistique and assess its build and performance. Right out of the blocks, a little sobriety here: It is Definitely a kid's "toy" Christmas scope both cost and target market; A cute, durable RFT. New cost was around $250 for the entire package; used now floats around $100, which is about what it's worth. The literature that comes with it is profuse! Noteworthy is the clamed parboilc PM 1/8 wave and SM (folding flat) 1/8 wave. The SM is mounted on a flat window; no indication regarding the optical quality of the window, though. I looked in from the front and the eyepiece side... YIKES! The fixed, factory alignment is WAY off! So bad that even bothering to quantify it would be pointless... so ~sigh~ there. Then I notice what (deja vu) I had seen with other cheap RFTs: The long, skinny focuser tube and undersized SM vignette so much that the whole PM cannot be seen from the image side. Is this a mistake? I don't think so. It assures that, even if the optics are grossly misaligned, the vignetted sampling of the PM will at least still see the full (albeit constricted) operational ~f/6 AKA "aligned well enough?" This of course manifests as the 3-inch entrance pupil displaced laterally on the (now oversized) PM. In my case, it is displaced so badly that it indeed clips over the edge of the PM. But note also, that the imagery may indeed be sharpened by (intentionally?) clipping the PM like this). One would then suspect that maybe the scope was properly aligned when it came from the factory; I doubt it. This thing is so glued together that said kid could kick it down the stairs and it would maintain. EVERYTHING is glued in. Well, you would think that after this examination... I would have at least taken it out so see how it works. Not yet, it's been snowing. But I intend to do that and report back. I expect it will perform "sorta OK" at the very low 25x delivered by the provided eyepiece. And THAT would be worth $100. So here I get a bit sneaky... If they are all like this... what if I were to replace the PM with a really good one, mount a good, properly-sized SM on a stalk/spider, elim the questionable window, and of course critically align PM/SM/focuser... and install a great eyep (Delos 17.3?). The imagery would be astounding! I would actually do that, except there seems to be no way to dismember this thing witoud demolishing it! Tom Dey

Yikes... they are indeed out there. Some person once tried to sell me a too good to be true tractor on Equipment Trader for a mere $7000. I offered to buy immediately, but researched the address etc. and he instructed me to wire $$$ to Italy because he was "going on vacation" but would leave the tractor in the driveway, in Pennsylvania... yep. BTW, I always use PayPal "Goods and Services" and happily pay the fee. I only use "Friends and Family" for ... friends and family! Menbers' history here is of course an excellent indicator of legitimacy! Tom

I plan/intend to get the 36-inch operational in the observatory by this coming solstice. Got the mirror coated with enhanced aluminum last spring at Evaporated Metal Films (EMF) in Ithaca, NY. I went out to the storage shed to check on it, still looks great. Just added a couple gun safe heaters (16 W total), two GIANT indictor silica gel desiccators, a viewing window, and a thermometer. Will have similar protection at the telescope (in the dome) as well. Determined to get 1st light early this season!

The pics are self-explanatory. Protecting the glass and coating are paramount. Tom Dey

Two obeservation reports: One (mine) yawn ho-hum. Second (friend's) quite exciting! First mine: Was last night, so sorta timely ~After Dark~ Here, near Rochester, NY ideal location and clear. But it was 8F outside, so I just watched it with binos (Zeiss 8x20) thru the living room window and saw Aldebaran "snap off" at 11:12:13 p.m. EST 20170304. That's a scientifically useless data point... but fun nevertheless = satisfying Amateur Astronomy. I was about 30 miles south of the Ideal Grazing Trajectory. Computed that 0.020 arc-sec star should take approx 0.13 sec to wink out = too fast to notice visually, but plenty slow enough for a few frames on a cam-corder to witness. A fast-response photometer on a good scope would nail it magnificently. Second friend's observation: Carl intentionally placed himself about 700 feet south of the "ideal mean" trajectory, else risk seeing no occultation whatsoever. Result? He saw Aldebaran wink off and on NINE TIMES over a period of [about a minute?] Scope was a 5-inch refractor at 21X. Lat 43d21m00.21s Long 78d38m07.11s Ele 91m. Very cool, indeed! He didn't log the time(s) else miss watching it! For both of us, it is reminiscent of that time a pretty bright start cut right thru Saturn's Rings a couple decades ago, winking on/off/on many dozens of times. I had observed that event, mesmerized, using my 12-inch Cave Astrola from my dome here. Has anyone seen a grazing occultation blink more than nine times? I'm thinking Carl may well have set a (visual) record? Tom Dey

Does anyone out there know of a supplier for Two-Inch Truss Pole Clamps? I'm building my 36-inch DOB now, and these 1.5-inch, that I have, seem too darned wimpy. Just ordered the 2-inch poles, but nearly all suppliers of Clamps seem to stop at 1.5 or are out of stock and out of production on larger. The clamps are just simple enough, that I can custom-machine my own... but that always takes longer and costs more than just buy and integrate. PS, I'll probably be selling the 1.5: nice, new, Obsession cast Upper Clamps, AstroSystems Lower Clamps, and 8 ea 8-ft truss poles. Tom Dey

Hi Matthew... Ummm Yikes! Is there no counterweight at all on the other side of the Alt axis? Ideally, the smaller scope would want to go there and act as (part of a) counterweight. I actually did that long time ago with a 4x5 "Constellation Camera" vs a 6-inch Newt observing/guide scope. That arrangement is relatively light, stable and keeps the center of gravity right over the tripod/pier. Tom

I rarely look at the planets - common conceit of a Deep Sky Guy. But took the 100mm binos out on the deck this morning and took a peek at Venus, 152X. ZOUNDS, It's gibbous! Facing east and ~north is thataway~ etc., I realize it is receding, so I missed the nice, big, crescent phase. Sometimes it's nice to observe "in the blind", intentionally forget what things are supposed to look like. David Levy et al often recommend that attitude... to "discover" familiar objects afresh, just sweeping the heavens sorta at random. This also agrees with one of the most effective tricks to successful [scientific] research: Don't be TOO Structured in your experiments... you will preclude the greatest discoveries. Related: A Very Effective Trick we used at work (Aerospace Research Skunks Works-ish)... was to concertedly have at least ONE guy/gal on the Team who was decisively NOT experienced in the particular focus. Too many Expert, Experienced Cooks, hobbles creativity with blinders. Tom

Yippee! My article just appeared in the latest issue of Amateur Astronomy Magazine, issue #96! "An Easy Fix for Astigmatism." It covers ways to eliminate objectionable astigmatism from your telescope, especially big Dobsonians. Tom

DESCRIPTION: I've had these for a couple of years now, and have them nicely optimized for viewing. Here are a few pictures. They are in a shed out behind my (rural) house. Still adding some bells and whistles, but delighted with the comfort and views. Some tech specs: Mirrors are custom high-end that I out-sourced, also great figuring, testing, enhanced coatings (OWL), better flat folds throughout, encoders. And even Night Vision eyepieces both sides. USE: Bino vs Mono picks up a full mag and better combined visual resolution, NV gains another mag vs traditional eyepieces. NV + 12nm H-alpha enhances nebulae tremendously. My favorite objects are globulars, galaxies and, especially, groups and clusters of galaxies. These are VERY comfortable to use! Tom

picture 1 is the observing shed, seen from the back deck of my house.