AlexK

Yes, the EP is a must, and it must be focused at infinity, as the whole point is to keep the laser beam collimated (otherwise it will fade very quick and will be useless for pointing). But if you plan an adapter for a particular telescope, you can try to reach the focusing lens inside of the GLP and try adjusting its focus to match your telescope objective (it need to produce an expanding cone matching your objective focal range). Just watch the beam, it must exit your telescope collimated. Or you can dedicate some cheap EP for that (still both need to be focused at infinity in the telescope).

Sure thing you can! Just keep it safe (for passing aircrafts and yourself, as the back reflection from the eyepiece eye lens may blind you). A red dot finder (RDF) will work as well, actually. And is in fact a preferable way, but it has some issues indeed.

Sadly, you forgot to mention your telescope and mount models. Knowing what you have to deal with would attract more folks with the same or similar instrument willing to share their experience with it (you can add it to your forum signature to save the time in the future). But in general, if you don't want to learn for too long and just need the result get a cheap green laser pointer (GLP), set you scope to point to the pole (0/90 on both setting circles or command it to go-to there), and just shine your GLP into the installed low power eyepiece. Match the end of the green beam exiting from your telescope with the Polaris (I hope you know how to find it in the sky naked eye? Big Dipper, Little Dipper...). Then work with the optical pole finder for more accurate PA. There are not too many bright stars around Polaris in the FOV of a typical pole finder to worry about. For those no familiar with the starry sky at all, I know a person using his Android tablet with my star chart app in mirrored mode and 180 degrees FOV set on the screen. He is placing the tablet on the table using Polaris to orient it North-South and referencing bright stars from it as if he is in the center of the chart and seeing the sky's reflection in it. He is already quite proficient in Northern constellations! Some other charting apps may have a similar feature as well.

Unearthly view indeed! Great job! I wish we could see it naked eye like that I'm in the SFBA too (Albany). At first I thought that's the Mt. Diablo from the N-E side. But then figured these are much smaller peaks looking that bold due to the HDR effect. Where is it really? Just curious.

That's a convincing experiment indeed. Perhaps, you've got some special PLA by an accident? I recall some PLA Plus circulating around. Also that's only one year of exposure so far. I'm printing since early 2014. One of my first prints was a white PLA conical capsule (just a 3mm-thick-walled, no infill, conical tubing with two springy-fit caps on each end) for the fire-starter kit storage, snug-fitting the hollow handle of my Cold Steel Bushmen knife, which is just sitting in its sheath in the GHB (Get Home Bag) most of the time (so almost zero exposure to anything drastic). A couple of years ago (so that's ~4 years passed) I needed to use that kit, removed the capsule (strong push from the narrow end) and immediately noticed that capsule's ends around both caps have many tiny cracks, they fell apart into several dozens of small rectangular pieces as soon as I've tried to remove caps. I.o.w. just the stress from tight fit caps destroyed PLA layers in perpendicular direction. Nothing like that with early 6 years-old ABS constructions under a similar stress, nor with 4 years old PETG things... And that's just one example out of almost a dozen, the most sad one being the wide/macro lens keychain holder for my smartphone crumbling on the latch pivot bad enough to lose the lens somewhere in Australia bushes. So, I would advise inspecting your marvelous white binos in 3 years to be safe EDIT: Another hypothesis (reading Gina above) would be to see if the hygroscopic properties of PLA may play a role in humid GB climate But I'm in front of the Golden Gate (San Francisco) as well, and the thick fog is passing through the eucalyptus forest at the base of my dwellings highscrapper almost every morning (the GHB is watertight though)...

My thought exactly. It is a nice project indeed, but the 3D printed design capabilities aren't unfolded their true potential here. It's just a way to avoid building a jig or tediously shaving and lining sectors surfaces for the otherwise totally standard platform design. To answer your question, this particular platform type is not compatible with the rack-and-pinion (actually long rack sector-and-) driving natively, because its sectors are sliding and rocking on the bearing surface as the HA changing (they are not following the ideal circle). It will be hard to implement a cog following them. However, you can add such a mechanism on a separate "row" of the virtual cone instead, e.g. right behind the sectors assembly. The sectors row will take all the scope weight load, while the actual driving will be done behind them. Moreover, you can use a trivial 1/4"x20 metal rod and have a venerable worm drive for that 3D printed cog sector with an enormous gear ratio and miniscule torque required, so even a 5V DC motor on PWM controller will do the tracking just fine, just add some lithium grease to delay wearing (when worn out, just print that little rack part again). You will lose the slewing feature that way (which is fun to have indeed), but you will get the rock-solid slipping guard, while adding a simple 3D printed rocking mechanism to disengage the worm (e.g. with a side or front pedal) would allow to move the platform manually for resetting (even $1000+ platforms doing just that or even less). The PA slewing idea is good, but I would instead just incorporate a cheap laser pointer module to hit the Polaris directly before the scope (or even its rocking top board) is on the platform yet. The sub-degree PA can be skipped in favor of the convenient speed control, as instead of the Arduino and the dedicated display screen (another unnecessary complication scaring many folks not skillful in electronics), which is hard to operate at your footsteps, I'd use an ESP8266 or ESP32 chip and have all controls on the smartphone (no need to learn smartphone coding, as these controllers can host a Web server and providing a dedicated standalone WiFi AP, so you can control your platform from a simple web page in the phone web-browser, E.g. see my recent Ultimate Blinker project). Even more than that, with the 3D printer at hands you can experiment with removing ALL metal bearings from your construction, e.g. from making it on friction bearings exclusively all the way to making the FULL conical-needle-bearing-with-slide-stopper for the entire front and rear sectors... The sky is the limit! PS: Such a platform is indeed a good thing for the automatic imaging of planets, however for the visual enjoyment I would rather invest the creative energy into your telescope mount fluidity. I'm personally having no single problem or issue pointing (Telrad and lately the QuInsight) and tracking (all the way to my maximum of 810x) with my 12" 16 years old classic Dobson. It's rock stable and smooth moving in all directions thanks to the 100% classical Dobsonian scheme (well, with a slight deviation of spring loaded altitude axis) and the trivial sliding magnetic counterweight (that explains why I'm still on the fence with my 3D printed platform, even though the dedicated Baltic Birch ply piece is waiting in my man's cave corner already ).

One more option would be to convert that stock 8" Dob into a simple truss, that would for sure help to travel with it (car or even a plane), but it would most likely gain some weight instead and become a hassle to assemble and collimate each time. There are some other options to offset that, but they will depend on the DIY mechanical capabilities / ATM appeal of the OP. E.g. my own plan is to build a single strut "ball scope" out of some decent 8" 1:4 mirror set (I'm on a lookout for one already).

The car back's size is not a legit excuse! When my whole family is going camping, my 12" is traveling on the roof rack of my Subaru Forester in the dedicated cradle:

The ideal solution for you (the OP) is: https://optcorp.com/products/vaonis-stellina-smart-telescope Seriously though, I'd recommend learning how to move your 8" around effortlessly (I bet it was already very well covered above, as a 8" is actually a very small and lightweight Dob; in my opinion, even a 12" full steel OTA is a single-handed carry still, but I understand people have different body builds). Otherwise, I doubt you can have better views than your 8" with anything less in aperture DSOs or planets doesn't matter, unless you would seriously consider moving to the above linked EAA path.

Drastic temperature changes are indeed a bummer. I had a trivial 1.25" adaptor, converting my tele-lens to 70x300 frac, exposed to -10C for ~30 min and then could not use it, as eyepieces simply can't fit. Threaded adaptors will suffer even more as the thread pitch will change, and possibly unevenly. However, it looks like if parts are mated that's less of an immediate problem, though that might depend on the actual topology of the part, e.g. a dense uniform infill might cause weird shell deformations. I can imagine a design with flanges being pulled far enough to break the threaded shell off. One of the solutions would be to avoid any infill and print enough top (or bottom) surfaces where it's threaded. By the way, that's the proper way of printing solids. The 100% infill I saw mentioned above might be (depending on the "AI" of your slicer) printing very slow and possibly with unpleasant artifacts. So just divide your part's height by the layer thickness and set that many tops in the slicer instead. I'm often using that to print only some top or/and bottom portion of the part solid, and the rest with some infill (in fact 20% is the highest infill I ever use as anything more seem to have no value for the rigidity or anything), usually, that's ether a slim geometry or a thread/bayonet I want to reinforce a bit. Oh, and regarding the PLA in the car: I had a sophisticated GPS holder built of PLA and some screws installed high above the driver side vent. On one winter trip through Yosemite (to a remote uber-dark "B0" observing site in Nevada) with the heater cranked well up, I've reached some road fork and glanced the map again... but the GPS was gone! I've immediately pulled to the shoulder as I was afraid it might end up under pedals, jumped out and down but couldn't find anything on the floor. Then found the holder and GPS hanging under the vent with all four holder consoles graciously bent down 180 degrees. I.o.w. it's not really melted, but softened enough to give up under a rather minimal load.

(in blue - my marks for the reference) A. I have no problems with that. Properly designed and printed ABS parts can support the weight of a car! I saw plenty of projects for my Subaru Forester, like making adaptors to foreign suspention. B. Stretching is the same. You just need to adjust your design for the possible stretch/flex distance at the projected load. Quite contrary, that's the important property of plastic parts which you can harness to minimize the number of metal parts (often fasteners) in your design. 1. Slim parts have their place in certain designs as soon as they are not for any serious load bearing. E.g. dust covers. But in fact you will be surprised how strong a 4x0.1mm layers plate printed in CF-nylon! I have printed a "credit card" sized piece with cut-out micro tools in trivial PETG, and had a hard time tearing out these tools (with dedicated tearing ponts holding them in the card's shape) by hands, had to resort to the wire cutter. 2. Never print anything in PLA except temporary pilot designs, temporary fixers (like shims), and toys. It melts in the Sun in summer and in the well heated car in winter, even from trivial friction, and also became brittle after a couple of years of exposure to elements, especially if handled a lot (from biodegradation of the material). Just from my personal experience.

In fact, all you really need is a patch not much larger than your Dob's footprint. Just pour a 3-4m tall pier, follow any tree house plans to build the wider floor around it at the top, add a folding attic ladder, and finally that plastic dome on the top. Just make sure it's on the North from the green hose To stay on topic: The most simple telescope setup I ever had is the "ball scope". My travel mount for it (I have ES Astroscan) is a trivial 18mm plywood ring. There are lightweight designs of them in decent sizes as well. E.g.: Pierre Lemay 8" (on an elaborate tracking platform here):

I believe that FDM is an order of magnitude more precise process compared to the mass-production inject-molding (IM) used in the typical production of "cheap plastic telescope focusers". Also, you have much more control over its design, so you can overbuild parts on purpose if concerned, which is a no-no for the mass production shaving each cent they are investing into the product cutting corners everywhere. For example, there is a well known fact that IM forms (molds) are aging (deteriorating) really fast, so some later batches of mass-prod. plastic parts might be on the very edge of mechanical tolerances creating horrible experience for unfortunate late batches buyers. I saw one Astroscan telescope tube (two parts IM form required to manufacture it) with one half visually smaller on the UTA end than the other due to that. It's a miracle they've managed to get the secondary collimating with the front glass at an angle. With the FDM process it depends on your new spool of plastic only. So if the pilot print doesn't mate, just adjust for that and reprint. That's only cents over the "budget", while new IM forms might be hundreds of thousands.

Yes, it's printable and even works and looks just fine. But there are unavoidable FDM deposition errors which making the thread's precision not only uneven but also "polarized". In a nutshell, that means zillions of hot spots on the plastic threads' surface which will be eventually removed by the use with mating metal thread(s), but may leave weakened spots and damaged layers (delaminating as threads geometry obviously weakening layers adhesion periodically) with unpredictable reaction to the stress in the plastic part which will grow with use (and time if done in the biodegrading PLA). Add to that the stress from metal thermal expansion/contraction and you will see why I would never use it for an EP filter holder, for example, as it's used too often and may be exposed to elements. But a more permanent adapter should be OK for several years. Then just print it again.

Good find indeed. I'm tinkering with this ESP32 bundle lately (M5StickC) : https://www.amazon.com/gp/product/B07ZGHX3SC They have many modules already, 3D print designs for them, and a very nice online IDE for "visual programming".

Are you restricted to paper pocket atlas options only? As smartphones are pretty much pocketable, and star charts on them are light years ahead of any paper creations ever made...

I'm in the hobby since 1979. The aperture does matters still. Even though the physics is gradually changing and even being revolutionized, it's not that drastic You just being confused by the psychological transformation of your hobby attitude. I'm enjoying it even naked eye as nearly every starry region I see is linked with amazing observations memories. But certain treats are physically unreachable without some optics. And the rule of thumb still stands: 80mm refractor, 150mm reflector - is the way to go beyond learning basics. I'm personally wouldn't go any less than 12" without feeling I'm sacrificing the views. In addition, AP-ers have lowered the plank in unprepared minds a lot lately, thanks to the computational power at their disposal. They are creating really inspiring masterpieces with just 60mm lenses every day around the world. But the eye is a very different instrument.

The effect of a dense forest location is simple: it allows your eyes to dark adapt deeper with no artificial lights in direct view. The light dome above you is still uber bright. So instead of sacrificing the horizon seeking for such a location I would instead look for a high rise location to poke above the megapolis smog and to leave all lights well down below (I'm doing exactly that on the roof of my 15 story condo complex when desperate to see something before the usual New Moon weekend trip to the really dark location). In fact, if you've got a 8-12" aperture, you can learn "intensive darkness adaptation preservation techniques" and stay at home with nearly the same result as observing from at least a green LPZ (colored Light Pollution Zone on these charts).

Good job! I'm sure you'll find the way to alternate/outfit that dry bag to secure the OTA. For the base - it takes some practice to carry it conveniently by the handle. But I would make a bag for it as well, even if just to protect it from elements while carrying outside. Consider a cloth/PVC-fiber bag with two side handles, so your friend could help you carry it conveniently. On a side note, I'd recommend to remove that eyepieces holder on the front of the base. It's just a snag-point. Keep eyepieces in your pockets, that will keep them warm and prevent fogging in the cold. Regarding the roof access, you might also try other buildings around where you friends/relatives might live. I bet it's not a big problem in Kharkiv, there should be plenty of concrete-slab 10-story buildings built in 80es-90es (flat roof) around, just make new friends

If you describe just one, I bet I could narrow it down to the filament issue By the way, is there a dedicated general 3D printing thread on the forum? So we could avoid hijacking this one chit-chatting around the subject?

Looks nice indeed. Reminds my very old project (I have my 3D Printer from 2012) for mounting a 2" NB filter on the Nikkor DSLR lens. So if you plan to replace it often, check threads periodically. I think, for such a trivial adapter it would be easier to just re-print it again when it starts showing signs of wear (vs designing a threads-less cassette mechanism). And that's another benefit of the 3D printer at hand: nonstop improvement possibility.

Exactly. The actual problem is not the printer but the filament. Even from the same vendor the same filament type may print different between batches. Add to that the hygroscopic nature of almost every filament, which means it may print different after a day of sitting open on the spool rollers. I would recommend simply learning your particular printer quirks (Ender-3 is a good modern enough choice for tinkering at home no doubt) and test-printing each new filament you get. With experience you will know at once how to adjust your model or slicer to fix any issues (or use them to your advantage). I'm personally never expecting my prints sub-millimeter perfect, thus keeping a toolset of precision woodworking chisels, Dremel bits, and the fine soldering work heat gun at hand.

This concept is known as GAG: "Grab and Go". For some that's a small refractor, for others (me) it's a 12" classic Dobsonian thanks to my Dolly (short range GAG) and Cradle (long range GAG).

Too short nights. After 40 years non-stop in the hobby, my equipment and the DSO visual observing flow are perfected so much that I'm observing from dusk till dawn with no single annoyance, pure joy, and just want more. Clouds? I' have settled in California on purpose Can't recall single time driving out and not setting up for some awesome views (also because I have 4 well established remote locations in different directions around the home to choose from after observing the weather pattern for a week before the usual New Moon's go). Correction: except for the late trend of raging California fires of course. We had Smoked Sun Eclipses on some days when all automatic street lights remained on well after the noon, and my remote locations was not excepted.

Please, report your findings when available! Who knows? The ideal approach, I think, would be to make that disk custom-tailored to the particular telescope. Following the BrendanC idea (the post he has linked above) the ideal sighting collimator can be made on a transparency film from the contoured image of the internal edges/reflections view shot through the piphole when perfectly aligned by other methods. If workable it might speed up a travel truss collimation task (for example) tremendously. That's what delaying my DIY air-travel 8" prestressed truss project, as I see the every night collimation as a serious challenge of owning such an instrument.