AlexK

For UK high latitudes you have to follow certain designs. The one above will be hard to reproduce as the gravity vector have to be split between two directions, thus direct driving you are considering might be inefficient without additional measures (like gearing sectors, fine coating of mating driving surfaces, expensive bearings, or that classic tangential threaded rod). I would instead leverage the 3-points of contact designs with the South single point pivot bearing raised high for the ultimate platform stability and sliding horizontally sectors, which will allow the direct driving by the horizontally rested motor shaft. However, with the modern electronics advancements the cost of a nonlinear motor controller with BT/WiFi connection to the head unit (for that hand controller) is around $5 for the most capable microcontroller allowing even the voice control e.g. the ESP32). So no need to compromise or over-complicate the mechanical side, especially for a large heavy instrument which inertia might be devastating if the platform slips by an accident. I've been personally poking the idea of leveraging a linear actuator for my platform which provides the zero-slipping guarantee. OTOH, the cost of 3D printing is also so negligible lately that I would rather design a fully 3D printed, fully teeth-geared system with replaceable parts for any latitude mounted as needed when traveling (e.g. I have 3 primary observing locations in California, approx 6 degrees of latitude apart max. So, having just two inserts I can cover the entire California if I don't like tilting the platform for that much (which might be dictated only by certain flaws of the construction not taking care of wide enough CoG position variations, which is easy to address during your custom-tailored design phase). As you have already mentioned this (subject of the OP) platform is a commercial endeavor targeting the production costs slashing. A DIY platform for your specific telescope (or range of telescopes) could be made to perform MUCH better exactly due to the simplicity of a single latitude design.

Just got that first smartphone camera prism in the mail. It is erecting (correct, not mirrored image). Otherwise it's producing nice images with tolerable vignetting at short edges of the camera frame. Some masking might be crucial though, as I had a position with kinda "split screen" which might confuse the algorithm showing stars on the shot from a different direction. Also the integrated clip is overlapping the screen too much on my Galaxy s8. (The image is rotated to show where the bottom of the frame with the mirrored ghost image is; the black stripe is the roof of the prism, not a terrestrial obstacle)

Nice find Mark! Yeah, at least the rear sector is also fully movable along the meridian for sure. See two rows of holes in the bottom plate? They are for the ball bearings caret shifting, probably per degree of the target latitude. So it can be reassembled for a different latitude using that mechanism first, then adjusting the tilt everywhere. The front one need to be only tilted to match the new virtual vertex position of the cone defined by the second radius. I can also see a clever declination adjustment system with the end stop trigger as well. Do you have a direct link? Or that's a prototype?

To verify if your laser collimator is collimated well enough simply rotate it in the focuser. To avoid false positives make sure you hold it approximately at one wall (usually the one dictated by the gravity) and tight to the rim of the focuser to define the orthogonality. If it shifts less than 3mm around the donut target - that's OK. However the final check must be done with the star-test. The acceptable collimation accuracy depends on your targets. E.g. for planets you want an ideally concentric airy disk at least within 1/2 of your planetary eyepiece FOV. I'm second to the Barlowed Laser collimator advice. It removes a lot of uncertainties and deficiencies of cheap stock laser collimators. For the starter you can try the simplified Barlowed laser method: simply stick your laser into the Barlow, and observe the shadow of the donut right on the laser's screen, as you would do with the dot. That's exactly what I'm doing for almost a decade checking the collimation of my z12.

Yeah! Nice device for that time. I have re-flashed mine almost the next day with the Cyanogen Mod Android. Just until recently it was serving as the living room music player "head", but lately everything has been "hijacked" by the Google Home ecosystem. The OtterBox defender is also roomy enough to undercut its back and allow the HTC accepting a double-capacity battery.

I see you've got i7? That one on my blogpost is a 10 years old phone (HTC-H2 iirc) in the OtterBox defender case. It's actually much lighter and smaller than my current telescope phones Galaxy N4, and N7 (also in the OtterBox) an I bet than the i7 as well . For the phone power, just reboot and enter the "Airplane mode" immediately. You will be amazed (at least on Android) how long a 3-4 AmpHours battery can go on the red on black AMOLED screen. I do have an elaborate power-bank-counterweight piece of gear on my Dob, but rarely have its magnetic cable connected to the phone.

Gotcha. Still, I can see benefits of independent components control vs all eggs in one box. An advice for the app: Make it WebView+CSS+JS driven. That way you could port the UI/API to almost anything (even to the ESP32 and make it nearly headless) and would allow users to customize it to their liking (in CSS, or you can help them with that). E.g. the "Night mode" UI switcher can be implemented in 15 minutes. Following!

Re SLS: I have figured that's an ordered print. Just teasing you with the possibilities opening when you have a fast prototypes materializer at hand 🧙‍♂️ I'm often so pleased with mine that skipping the "final" print ordering. Re the "snubnose": Considering observed swinging forces I'm experiencing on my smartphone holder near the focuser of my z12 for like a decade already, I would hesitate trusting the friction-only holder not only for the camera position stability but for its safety 😅 For the design, I'm leveraging the "3-poins of grip" principle with great results to avoid any play or the need of fastening screws.

The lens speed would be indeed beneficial to some good extent, however the CSSE plate solving is leveraging true stacking of video, so if there is not enough light it might decide to double the stacking times (more frames, more deconvolution time, which is still just additional several seconds in a worst case) and then either command you to proceed with pushing on success or report a failure but in the latter case you have saved on the Push time. The stacking base increase equals to improving the lens' speed proportionally, thus the latter is not that crucial.

That's not much work, just time to research camera API implementation and the way to hijack its calls when necessary. I believe that best Android smartphones for the CSSE tasks flawless support are Samsung models listed compatible with the Samsung Gear VR technology. They have the best positional sensors (usually both accelerometers and gyroscopes) installed to support seamless virtual reality performance. That's because from the user's point of view the performance of the pointing with the CSSE software depends most heavily on the accuracy of the Push phase. Other phases can have a lag of a couple of seconds due to the busy CPU/RAM/ROM but if you have to repeat the Push after the second field scan you lose that time twice. As an added benefit compatible phones have faster hardware for 3D rendering. I'm still using the old Samsung Galaxy S8 smartphone in the GearVR headset when commuting for hours in the tour bus. The virtual 100+" computer screen in front of me feels being bolted to the concrete wall and I'm jumping in front of it on potholes of California freeways Exceptionally good sensors! Camera seems to be least important. As soon as it's clean and has no severe distortions should work.

Looks cool indeed! Minor mistakes are easy to fix in the plastic post-printed with a heat gun, or/and addressed if necessary in the v2. That's the beauty of the home printer: repeat until 100% satisfied (I would remove that brass insert along with the nylon screw as soon as you confirm the best fit position and lean the one-side-full-edge-latch design). But why you have resorted to the half-way-only printed case? Isn't that an obvious mechanical design defect?

The prism casing shape looks weird on photos indeed, so it could hide a roof prism. By the way, I had an idea once to investigate if it's possible to force the Android camera into the mirrored mode by default to fool the app on that . I.e. using root tweaks, or tweaking the camera API library (I'm Android software engineer).

Aww! Great find indeed! Flimsy, but unequal sized prisms are so rare that I'd get one anyway and retrofit into a custom 3DP design. (Got two. There is another smaller magnetic model as well) It might even have a non-straight flip angle making it even better than Celestron mirror (unless the vignetting is bad).

So, Imaging is a priority? Heh! Well. First see my comment above. But perhaps, you have a specific idea what you want to image? (That might reduce the cost requirements). If not sure, you might check this writeup first: https://optcorp.com/blogs/astronomy/best-astrophotography-telescopes-for-beginners?gclid=Cj0KCQiAhZT9BRDmARIsAN2E-J1WFBwpItB6J5JsQRP8t5TQlN0_n1kUpYmx2hKgzamlDtfAGvkBHDUaAgq5EALw_wcB

Good Dobson is very natural to move by your bare hands including while tracking. It relies on your skills, while slow motion levers of a GEM relies on the quality of its mechanics build (which is at that price is not stellar). You can always improve your Dobsonian operation skills to perfection, but not so much (if at all) your cheap GEM "levers" I had all kinds of scopes and mounts but after 40+ years settled on a 12" 1:5 fully manual absolutely classic Dobsonian. Automatic tracking is possible with any Dobsonian by adding a Poncet Equatorial Platform (DIY or purchased). Effortless pointing with a Dobsonian for a beginner has an ultimate year-2020-born solution from Celestron called Celestron Starsense Explorer, which is utilizing your smartphone mounted on the telescope or its mount. Though, at this point you have to buy their telescope to use it. See this thread: So if you are concerned about finding objects in the sky and don't have time to gradually master other pointing techniques consider https://optcorp.com/collections/starsense-explorer/products/celestron-starsense-explorer-dx-130az-smartphone-reflector . In your rural sky you can instead master great indirect pointing techniques with Telrad, which are rivaling even the expensive and uber heavy-weight motorized GoTo-mounted telescopes accuracy. I have explained the one I'm using for over a decade in my blog here: https://www.dobmod.com/2020/04/tpm-telrad-pattern-matching.html Eventually that tech will become portable to other telescopes. The point of manual pointing is to stay in touch with the sky instead of fiddling half of the night with GoTo electronics and complex mechanics. I think, the decision should be based on your long-term goals. If you plan to gradually master your visual astronomy skills over the years - get a large aperture Dobsonian, as it's the most rewarding. If you want to just point at some easy targets in the sky on occasion and don't have time to learn much - get some GoTo mounted telescope you can still lift assembled (yes, solely by its weight consideration). That Celestron Starsense explorer might be much lighter, but you need a compatible smartphone. But if a serious imaging is in your distant plans and you are an eager learner (and spending some dozens of thousands of GBP on that goal pursuing eventually is not an issue) - get a good (at least £1000) refractor or a CAT on a motorized GEM to start figuring it out right away.

Welcome to the forum, Webby! From my experience, any scope with the GEM (German equatorial mount) on a tripod is much bulkier and heavier than a Dob of the same aperture (even if with a longer focal range). Also, I believe that for a beginner a GEM mounted newtonian is not a good choice as it requires a lot more fiddling with the mount than a Dob or Alt/Az mount. In particular because the eyepiece is fixed on the side, so to make it convenient to use you will have to rotate the OTA nearly for every object, as you are not used to the efficient observations planning yet. A 8" Dob was a solid all around advice, actually, as 20cm is way more capable aperture compared to 15cm. In addition, there is no way a 8" Newtonian could be considered mounted on a flimsy particle board semi-fork, which some 130/150 Newts manufacturers are calling "Tabletop Dobson", they are not even close to the real Dobsonian smoothness and rock-solid stability. So, most any 8" Dob should be a "real dobsonian" by design. The only advantage of the GEM mount is easier guiding (tracking celestial objects), which is essential for the astrophotography. However that particular mount is not motorized, and in fact I have a doubt it is possible to image with that particular SW150p GEM through that 150mm scope. Surely, except for planets video and piggybacking a DSLR with its own lens on the OTA or on the counterweight.

Perhaps, 7+ years is a good enough time of service for a simple DIY design ? I'm personally usually have such stuff 3D printed as soon as needed just overnight since exactly the 2013th Nowadays, with the prices on good printers well below $200, there is no excuse for an amateur astronomer with the DIY passion to ignore that severely money-, time-, and effort-saving tech

A laser collimator (LC) collimation doesn't need a lathe at all. If you get this super cheap one on Ali: https://www.aliexpress.com/item/4000184670320.html you will also get the 2" to 1.25" adapter with it. Just clamp that adapter to something (no vises or C-clamp? Get a pile of heavy books around it). Project to the distant wall (5 meters - bare minimum), tape a piece of drafting paper under the beam. Mark the beam position. Then rotate its 1.25" body in the 2" adapter a bit and mark the spot again. Finally, find the center of the resulting circle, and then collimate with screws to hit it. Repeat if in doubt. I do the same using my stock Zhumell 2" to 1.25" eyepiece adapter. But if you have a standard ring or dot center marker on your primary and a 2x Barlow, then better yet, you can adopt the simplified barlowed laser collimation technique, which makes the precise collimation rivaling even the expensive autocollimator device a nobrainer: Use the LC as normal (get the laser return dot disappear in its bullseye target's hole by moving the primary). Now put your Barlow into the focuser and then the LC into it. Look to the primary from the front and wiggle the laser collimator until the center marker is well lit with the cone of the laser light (you should see edges of the marker well). Look at the bullseye screen of the LC and locate the shadow of the mirror marker (you may need to play with primary a bit, as the marker shadow/image is zoomed 2x+). Adjust the primary to perfectly center the shadow around the hole (pay attention to its ellipticity, as the bullseye screen is at 45 degrees. With experience you will just skip #1, so no LC collimation is ever needed as soon as the wide cone of the laser light can cover the target on the mirror entirely (you should be able to see its edges so the return beam produces a recognizable shadow on the bullseye). Another typical flaw of cheap LCs the non-circular laser dot will be even beneficial with this method as it's making the barlowed spot even larger .

Awesome project! Thank you for sharing the progress in such great details! I just had a thought to share about the possibility of unifying and simplifying it by splitting everything to multiple self-contained functional components (vs integrating everything in a single box) by utilizing a bunch of ESP32s. I.o.w. each probe and each heater would have their own controller box attached communicating with the CPU over BT or WiFi. You can think of it as of "Internet of Astronomy Things" That would in a snap reduce the need of wiring to just the common powerline (OTOH you can easily opt for probes being completely wireless, as ESP32 can do just fine on a single CR18650 or even less for weeks); remove a lot of connectors, possibly even the custom PCB, and allow to move related components closer together reducing the power consumption and heat buildup (and heat loss if you move mosfet with its sink directly into the heater module) make the system modular (thus extensible, maintainable in the field, tunable, and upgradeable); and could allow replacing the primitive Arduino CPU with a common smartphone with much more robust and easy to tune on the go software with more convenient user interface possibilities. What do you think? Doable?

This one I guess: https://www.amazon.com/MEOPTEX-1-25Inch-Collimating-Cheshire-Eyepiece/dp/B07KF191VL Looks the same as that FLO. IMO. You can find a laser collimator for that price. And don't buy their "sighting tube" ad. As a sighting tube supposed to be individual for a particular aperture.

These padded bags are actually for safe transporting. They are an overkill for the storage. Just make sure the chemicals are safe for coatings, avoid spills/leaking of those you not sure about, ventilate the space periodically, and surely give all your scopes a periodic "walk" to fresh air!

Careful with those chemicals on the shelves nearby. Certain vapors or spills might damage optics. Even plastics might emit enough to affect some coatings in a long run.

My smallish scopes (ETX-125 and Astroscan) are capped on display shelves. The 12" full steel OTA Dob is on its base in the wall closet on the 4-wheel furniture dolly, with the OTA upside down (tied to the wall). Both ends are covered with tight fit plastic trash bags. That way the residual dust is collected only on the secondary and easy to blow through the focuser. The primary is at maximal safety from falling debris and possible live crawlers. The focuser is protected by the wall of the base down below (as I have my camping/travel gear in that closet which I might move around on occasion). Also, as I have the Velcro dots mod for the primary holder cell, that prevents overcompression of the Velcro as well. Surely, the best way would be to keep the OTA horizontally to minimize the dust settling, but I don't have such an enclosed space readily available for grab and go. For over 10 years my z12 is stored like that after field trips. No issues.

Awesome tutorial. Very inspirational! Thank you Dave. Though, why you are saying that eclipsing variables are the easiest to start from? Most are actually quite constant between eclipses for days. I would start from cepheids instead exactly for the reason they never stop changing (well, when they do that makes world news ).

Just keep in mind, folks, that forced heating is inferior to the insulation in astronomy applications. Because the escaping hot air might affect the seeing locally. Usually that's only visible near the Zenith as the heat escaping the face is nearly unavoidable. But the heat escaping from lower body might ruin relatively low planetary views as well.