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Everything posted by AlexK

  1. That's indeed an ideal trade situation. So just go grab it first, then post some images here, we'll assemble the Grand Consilium for that specimen in no time
  2. Second to that. Totally sane price for that 10" used (~$750 brand new, but on backorder everywhere, so will be at $1000 soon no doubt). Just make sure it's not damaged internally or externally and has at least some stock accessories. If you can't visit seller in person to inspect it with the flashlight ask for clear images of anything they consider being a defect. And at least the primary's image in white light focused on its retainers (must be spotless even if dusty). Then you can try negotiating if you want.
  3. Congrats, Michael! A decent light-gathering upgrade! The stiffness could be normal for it actually. This is not a Dobson scheme with feather-touch push/pull action you might be used to. It's a GoTo attempt on a particle boards fork. You supposed to drive it with buttons, not by your bare hands. The manual pointing operation is more like just an afterthought in such a design, so it's not like on a Dob and not like on a real Alt/Az fork mount. So to avoid any confusion I would try simply following the instruction manual step by step for automatic pointing (GoTo) first. That would also help troubleshooting the tracking issue, as most likely you have missed the proper mount alignment steps or lost it manipulating it manually in an unexpected way. Don't worry about your mechanical skills, it's still under warranty and on tech support, right? In fact, I would avoid any screwdriver tinkering with it for now, as that could void the former and make more expensive or lengthy the latter. Get to the support first (ditch it, and get a normal classic Dobson next <--- a joke, OK?). Disclaimer: All of the above is my personal opinion exclusively and leveraging my freedom of individual expression, you have rights to ignore acting on it in any way or interpret it in any way you see fit. (am I an ideal citizen now? )
  4. Yeah, that Zeiss Coude is a true modern marvel of the optomechanics of 70-es. But by now, its mechanical base aging renders it less beneficial for the intended scientific tasks. E.g. the detectors miniaturization revolution outweighs the need of professional maintenance (expensive and time consuming). So it's being replaced at observatories to cheaper to own modern solutions with even more capabilities. Good for amateurs willing to take the job of restoring that technical wonder! It was especially awesome for imaging, photometry, spectroscopy, Sun observing (manual sketching, heavy H-alpha stacks). Anyone not aware of the Coude scheme: its focal plane is routed to the Polar axis by two flat mirrors, so the view is permanently and precisely fixed to the ground, thus your eye (or any other large and super heavy opto/mechanical and/or electronic instruments of the 70es or older) stays immobile and focused down to sub-microns while you move the other end of the optical axis around the sky: Though at our youth observatory it was idling for years in a row due to mechanical issues started to pop up here and there due to the lack of scheduled professional mechanical maintenance. I believe by now it's just sitting in the storage partially disassembled.
  5. Re Dobson cooling. It should not be too much of an issue on the Islands as the temperature swipes are not that drastic there. I see it's like 20C to 10C (day/night) in the summer. So with the cooler fan it should be like 20 min. If that's still seems like a serious problem for your flow you don't have to wait, mod your OTA with the surface layer blow fan(s) and/or front duct ring. Folks swear that running it when observing is fixing the problem nearly instantly. Re atmospheric conditions and the large aperture. That's true, smallish aperture will show a smallish planetary disk kind of more neatly and for kinda longer. But what's the goal? Enjoy the neatness or see tough details? With my 12" I saw fine details in individual Jupiter belts clouds, as well as streams around the GRS! Yes for a second or two in like 30 minutes of manually guiding it uninterrupted at 640x, but that was truly striking, spacecraft flyby like experience, enough to forget about refractors and GEMs forever! Re GoTo. Better skip that doubtful feature on a furniture-particle-board fork mount which is typical for commercial 12" GoTo reflectors. It's never 100% reliable and a chore to use immediately and to service it over time. Needless to say it's rendering all benefits of the Dobsonian design to zero. So I believe it's just a dead(ly) weight . Yes, it still has certain appeal for a knowledgeable (or warned) newbie because of the tracking possibility though. Especially having in mind that the real Dobsonian mount (which is a breeze to guide manually) is a really rare find nowadays anyway as every China engineer has "innovative" "improvements" ideas of their own (including that GoTo gimmick). But still, for less or comparable money you can have an direct-focus-imaging-capable tracking added eventually with the EQ Platform (DIY, custom order, or even OTS). Wooden GoTo mount can't help even with the piggyback imaging. The trivial star hopping is way more reliable at pointing than that GoTo as soon as you get a properly designed for that flow digital star chart on a handheld device and practice with it a bit. And to give you a perspective: the manual telescopes pointing revolution, giving you a nearly effortless 100% reliable pointing possibility is just around the corner (I might be even not the first announcing it).
  6. I spent several years observing hands on with the professional high end 150mm Zeiss Coude refractor and with the high end Russian long refractor AVR-3 (also 150mm). Both stationary installed on their stock high-end motorized equatorial piers under the sliding roof of the local youth astronomy club's observatory. I can tell you without a single doubt: views with my current very-average-optics 12" Dob are very long way better in every regard on planets and DSOs (weather permitting)...
  7. Unless that would also involve our Sun turning into the Black Hole (what an astronomer's paradise is that! See a BH and die!), I will be still enjoying my ODA (Observer's Digital Assistant, a.k.a. dedicated astronomy smartphone) which objects database equals in ink and paper (required to print them all) to several tons of paper charts. Because I have a briefcase-size-folding 150 Watt solar panel (works well enough even in the overcast to charge a phone). That's the last resort after I have exhausted my 500 watt/hours power brick, 4 x 3-8 Amp/Hours pocket 5V power banks, and the ODA spare battery (yes it's still has a replaceable battery as that was the ODA selection goal!), not to mention two smaller solar panels for hiking and EDC, my in-car dynamo, and the small 1 Kwh gas generator (Oh, no! That one is out as it will power my fridge with cold beer)... Nope, I'm still good without the planisphere during the apocalypse (a.k.a. TEOTWAWKI)
  8. Cheers back NGC 1502! That's right. The Astroscan is the observing ergonomics high end of all times! And definitely a keeper! I got it from a fellow colleague amateur astronomer for free specifically for my son some years ago. Because this marvel is not for sale! Only for giving! But I considering it mine too as I play with it more than him Care for it well! Yours is even more unique! And it looks like manufacturers are not rushing a new model into production anytime soon for some weird reason By the way, you can find several mods and outfits I've done to/with my Astroscan on my blog. I have collimated the secondary and primary by shimming as well myself. It gives amazing views with the 9mm WO 101 AFOV! To stay on the subject: I do love planispheres. When I was a kid (8-18 y/o) I had a 2 meters in diameter, 7 colors printed press, laminated, DIY cardboard pieces backed, classic planisphere in Russian mounted by my father on the concrete anchor in the wall of my room. For the horizon overlay I've made a huge wire ring hanging down from that same screw (in later years back then I have added the overlay wire following my local urban horizon line carefully modeled over the course of several observing nights bending it between matching stars). I've made hourly marks from two old broken wall clocks (brass digits) on separate plaques glued to the wall around the chart's disk, azimuth points were made from red copper wire rings on the main aluminum wire... Needless to say that after literally living between stars for so long in my childhood I now know constellations' stars very well. If you point to any star in the sky, I can immediately tell its name/greek letter/flamsteed number, even if it's barely visible between trees. Or I always immediately noticing any "extra" stars (being that a planet, comet, an artificial airborne/space light source). Or, when I see any movie, or a piece of art (e.g. in computer games) depicting some starry sky, I can immediately tell if that's "our sky" or some alien/fantasy one because constellations stars are so obvious and familiar... But I would never even consider a planisphere as an observer's tool. Learning, demoing, studying - OK, but at the eyepiece I strongly prefer a handheld eyepiece view chart. EDIT: Simple orienting? Nah. Good digital chart has several much more effective basic orienting methods starting from mirroring the 180 degrees view projection, which makes the screen working as a "star compass" with constellations down on the table matching directions to real constellations in the sky. all the way to the StarSense Explorer software, actually "seeing" where the phone is pointing between stars and telling you where to move the telescope...
  9. How so? You have to use a bright enough flashlight to see its large white low contrast blinding beauty On a side note, it's easy enough to remember all these ~100 black (or blue what have you) dots and skip that redundant step for good while planning. A good star chart will show you what's up and what's not anyway.
  10. The above double-sided one is a way better design compared to the classic one. First of, it has much less distortions. Clean to comprehend, and even has lines teaching you the bright constellations stars finding with pointing figures. E.g. Arcturus is on the extension of the UMa "handle". Regarding planets not charted, Louis, you supposed to watch for the ecliptics line on that chart (dashed). Planets are bright stars. So if you follow the ecliptic line on the sky and stumble upon a bright star not charted on the planisphere, that's a planet (or an UFO). You can learn distinguishing outer planets by their color. While Venus and Mercury are day and night in brightness and always close to the Sun. Also, there is a common misconception that planets do not blink compared to stars, but that's referring way back into the days with no industrial pollution to speak about much.
  11. Planisphere is like a wall calendar. But if you don't know constellations, not aware of sphere to surface projections, don't know what the LAT, ST, LMT, UT, LST means, it's nearly useless in the field. But you can use it to learn all of the above. And even get an inner sense of the astronomy time building up gradually. Just hang it on the wall (see the hole in the corner) and move it like every week. Then memorize what's displayed on it, i.e. at around 10pm LMT, when passing by on your daily route. The wall in front of the toilet is a good learning place for it as well Just by the way, here is my pocket planisphere which is always with me (in the center) I watch it at midnight LMT:
  12. C'mon folks! A stepper's "back flush" current is rather miniscule and will be grounded by the driving MOSFET anyway (the controller is separated from "gentle CPU circuits" by the high power driver). I have my printer for 7 years and moving X/Y 250mm wide back an forth all the time. No issues. Never heard about anything drastic like that either. Urban legends. Disconnecting your motors you are just reducing connector's lifespan and possibly eventually crack the PCB from mechanical stress too.
  13. Hmm, like what you mean? There is an exhaustive database of ~2000 OCs in existence. What else an observer might desire above that? The "Best 100 Review"?
  14. Kinda unclear what exactly you have invented here without the full context My guess is that you have used that MSM rotator arm-head to place that orange block precisely against your forehead when at the eyepieces for better binos stability? That would work if the back of your head is resting on something fixed to the ground as well (a chair's back). If not, a very good cushioning is a must to prevent view shaking. Not just to feel it better on the skin. See the rubber eyeguards? They are not only for the side light cut off but mostly to prevent exact that problem at the high magnification when they are resting on your eye sockets bone. So, instead of a thick or long cushioning piece there I'd suggest 3D printing a simple scissors spring in the middle. It will be damping head shaking much more efficiently. Though it's main benefit is to unload these large binos weight on your face, not to improve the view stability directly. However, the latter will be surely benefited from your muscles tiring slower with that attachment. By the way, when I had a similar idea (head-mounted 2x54 monocular) I've got my head 3D scanned professionally So now I can design such "bionic" things simply subtracting that head shape from the 3D model. Try that! (just make sure your hairstyle is not getting into the way, I regret I didn't cut them shorter back then ).
  15. Lovely it is! But wondering why didn't you print the entire replica of that Altair and save some dough for a couple more NBs ? Should be totally adequate for visual e.g. in CF PLA and you can design it way slimmer than that Altair assembly.
  16. Oh my! Such a misleading user interface! What tripleped is asking for is "Rotate 180 deg" option. All I can see on that control screen are flips only. So people have to remember they need to tap "Both" or what exactly for the newtonian scheme to actually rotate it 180 deg??? It looks like the developer is thinking that the user will "match" the chart with their view, while in practice it's always in reverse: you match the view with the chart (that's the most basic navigation flow with any map!). So if the chart is not ALREADY rotated/flipped properly for the instrument a novice star-hopper is doomed as it is IMPOSSIBLE to match it with the EP view positively! That's what happening when developers aren't into the hobby themselves, because they never use their own creation for real
  17. Hey, Frank. Google for "rubylith masking film". The many years top praised brand for the exact that purpose in the US (I'm using it too), but might be available locally for you as well. I would also highly recommend the OtterBox Defender cases with the integrated screen protector (available for all top smartphone models and then some). They are not only protecting your phone in the field from elemens and kicks/drops, but also easy to open just on one side so it's convenient to slide in the precisely cut piece of the rubylith under that screen protector (transparent film). Other similar phone cases might be available for your model as well and cheaper. On a bottom-cheap you can simply use several stripes of packing tape going to the back. Just cut the film larger, as it may shift and expose a blinding content on the screen (especially care about the top and bottom of the screen where random popups are displayed (to minimize the latter I'd recommend switching the phone to the airplane mode).
  18. Gotcha. QuInsight glass is indeed slightly larger than Telrad's window to accommodate the wider AFOV. That might be making it more prone to dewing. However, Telrad dewing problem is quite overrated in my opinion. Lately, I'm just carrying a microfiber cloth (coming with nearly all glasses from China) in my dedicated astro-vest clean pocket, and when I see the glass getting foggy, simply wiping it on the spot. So far so good. The collimator don't need any wiping even when foggy a bit, as the reticle is still clearly visible. Though, I saw that later models of QuInsight come with the flip-off lid over the top of the mirror, which is another easy way to prevent dewing for much longer simply flipping it back when done pointing. Also, I can see all the DIY measures used for Telrad dew prevention easily adapted for the QuInsight nearly as is. And there is a potential for more ways. E.g. I had an idea of placing the heater element on the inside of the QuInsight column and providing small air vents around the lens, so the heated air would escape it with the natural "chimney effect" draw and heat the collimator and the mirror naturally. Should convey it to Rob one day.
  19. I understand the city dwellers problem with that. The QuInsight might address that very well for you. I consider myself lucky as even at home, practically in between of the two whitest blobs on the LP map (San Francisco and Oakland) I have quite a usable sky darkness for Telrad after sitting under the head cover for ~20 min. Telrad is great at direct pointing as well, but a Zeiss lab microscope is amazing at pounding nails into wood too! :)))) By the way, I just mentioned above (when you been replying I guess) that I didn't understand you last question: "Is there a way of preventing seeing as it seems quite vulnerable to this". Let me know if I've answered it above already
  20. Hi Stu. Yes, you are 100% correct about the TPM method. It's just that simple, and that's how Telrad was initially perceived. But back then it was quite an elaborate mental procedure as paper charts could not follow the real thing orientation, so you could not use Telrad rings gaps for direct matching (see below). The complications though are created by apps developers. Last time I was checking, the SkySafri had a very dumb Telrad reticle implementation with permanently fixed sizes of the circles and its gaps orientaton. The 1:1 (photographic) reticle representation on the chart is a bit doubtful to me as well. So if you actually try comparing your chart's screen view with the view in Telrad side by side, you will see that you cannot match the two exactly (in my writeup I have outlined all possible reasons for that). Such a primitive implementation could still be leveraged. Just get used to making little mental adjustments here and there when matching patterns (the centrality over the stars pattern is the key). But the accuracy will be significantly less stellar esp. for a beginner. The TPM's point is to utilize your inborn ability to perfectly match the stuff you see with the mental model. The human mind is quite bendable with practice though :)))) Also I know folks utilizing app's (SS and several other apps allowing that) eyepieces circles to amend that problem: just create 3 fake custom eyepieces and play with their AFOV parameter until the corresponding circles on the chart are matching the outer edge (or inner, just make sure it's a consistent edge to remember which) of the Telrad pattern you see in the sky. The single time effort worth doubling your TPM accuracy permanently. But with that you usually can't use Telrad gaps for matching still. There could be a way out as well: check if your app can show any crosshairs in the circles. If you are on an Alt/Az mount you want it to show Alt/Az crosshairs, on an EQ mount you want meridians/parallels-matching crosshairs displayed. Then you have to mount your Telrad on the scope so its gaps are matching the crosshairs lines. Usable with some inconveniences, but that's also the intended Telrad use way (gaps where supposed to show where the view moves as you push/pull the telescope on the mount in one axis, same purpose as those EPs crosshairs). Lately a well forgotten feature, as the viewing convenience is more appealing to folks using it as a trivial RDF :))) Though, if you at least pay attention to these gaps when moving the OTA, they are of a tremendous help when fighting the "Dobsonian hole" (problem pointing with the Dob near the Zenith). The above method, by the way, would allow to add all wider QuInsight circles to the existing Telrad ones in a pinch (by the way, the QuInsight reticle is also independently rotatable by the side screw head). DSO Planner is not affiliated with the Rob's creation (QuInsight manufacturer) in any way, but I'm a really happy buyer! And I've been in tight contact with him directly when being ordering mine, as I needed a special manufacturing order for the glass mirror (better transparency) and a particular base box lid alterations (to incorporate my blinker circuit in it). Sure thing, I have implemented the native support for QuInsight in my app as soon as I got my hands on it and realized that's the true game changer for the TPM use cases expansion! Still highly recommend it! Umm, not sure what you mean by: "Is there a way of preventing seeing as it seems quite vulnerable to this" ?? Please, elaborate.
  21. I'd like to share my own observing chair design on this wonderful forum. I think, it's well described in all the deatils on my blog long ago, though as many folks are turning into the DIY and ATM hobby during these harsh times of opportunistic price tags and long out of stock wait times it always good to have alternatives to consider, especially with the help of a fellow hobby colleague readily available for consultation in a convenient free-chit-chat format So here it is: The Six-in-One are: The tall smoothly adjustable to any height observing chair with the convenient backrest, elbow rests (full arm rests are doable in a snap), foot rests, and even the backboard slant adjustment for the perfect balance. Ground transportation cradle for the 12" 1:5 full steel OTA. It has wheels, wide sled skis, handles for 2 person carrying, free-standing on 3 points (so can be walked in vertical position, e.g. into an elevator, wall cabinet). Long 18" high table with one open-top storage bin, and 4 x 2" EPs holes (you can drill more :))) ) Car roof fully enclosed box with resting/braking points for arched roof cross-beams. It survived the attempt to pass through the not fully opened commercial garage gate once :))) (roof beams were bent, but the box protected the OTA) Car trunk transportation/storage drawer for quick loading, securing, and deployment of the telescope. Vertical cabinet storage stand for the OTA. Some folks had been suggested several more uses, notably the wind screen frame and the toilet seat :))) The transformation between "modes" is done with the help of A small electric screwdriver (Phillips screw head). Two wood screws (to attach "skis"). Two 1/4"x 20 machine screws (armrests attachment or chair module attachment). Two furniture legs with M8 thread (always attached to the "skis" but go into different "ports" in different modes). One 3/4"x20 threaded hand screw ("skis" cross-joining in the "chair" mode). Two HD bungee cords (to secure the OTA in the cradle and to secure "skis" angle in "chair" mode. Building materials are: A piece of 3/4" (18mm) redwood plywood (slightly bending bends under the load without breaking). HD wall shelves' extruded steel supports (L-shapes). - 4. Thick steel wooden fence gate handles (to procure 6 HD L-shapes) - 3. 1/4"x 20 machine screws, nuts, washers - 20. M8-like screws, nuts, washers - 8. Krieg 1 1/4" plywood screws (to produce L-shapes in plywood) - 12. Assorted wood screws for double-ply reinforcements and furniture attachment ~20. Wheels on aluminum L-shapes - 2. Furniture adjusting screw legs - 2. 1/2" x threaded rod - 1. 1/4x20 threaded steel wood inserts - 4. Outdoor chair foam seats - 2. Everything is done using very ordinary hand tools: electric hand drill, electric jigsaw, electric screwdriver, manual holes tap. The total build time I would estimate at around 20 hours.
  22. That's better than nothing, but not enough if you are after really deep views with your 12". The star charting app must support your EDA (Eyes Darkness Adaptation) natively. If it does not then it's a toy app for children amusement. The proper dark adapted app UI must be minimalistic and mostly wireframes based (less pixels lit) to limit your rods bleaching and prevent switching the perception to cones. Programmatic filters like above may render a non-supportive app hard to use at low light levels as its UI will be altered by that filter app (and many other similar offerings, including the iPhone red light mode) in a weird way, not expected by the app's UXD developer, so you most likely will have to crank the general brightness lever up to see it better, rendering that "redness" feature counterproductive for the EDA preservation. That's all only true for OLED screens. If you have an ordinary TFT screen you must use the physical red film piece (sometimes two) over the screen to reduce the screen glow where it's seemingly dark and at sharp angles where such screens leaking a lot of bright white light. On a side note, each phone screen is different at rendering its content, so on some phones the same app may be looking OK in the dark, while on another it will be just blinding or hard to use at low brightness levels (all the way to some UI elements being simply invisible). That's why a proper UXD design of an astronomy app for the visual field use must support elaborate colors adjustment! If it does not. It's a toy app made for the profit of the developer, not for the demanding end user.
  23. That's why you should not mount your GLP permanently as with that six-screws "torturing device". So any moment you can remove it and keep cozy in the inner pocket.
  24. Sounds like a good plan! Shots are not mine. Just googled them (saw them some years back). Original public content links are preserved.
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