This discussion revolves around a user's creation of a custom telescope mount, sparking conversations about open-source hardware and software, CAD design, manufacturing, astrophotography practices, and the trade-offs between open-source and commercial solutions.
The Beauty and Practicality of Open Source in Astronomy
There's a strong appreciation for the open-source nature of the project, especially in the context of specialized hobbies like amateur astronomy. Users highlight the accessibility and collaborative spirit fostered by open-source.
- "This post reminds me of the beauty of open source. Well done build and a great project summary!"
- "It's amazing how much can be done, but anything that I think will take an hour, lasts 6. Many times into the night." (waerhert, reflecting on FreeCAD usage)
- "It’s a wonderful hobby and I think the latest in 3D printing and PCB manufacturing does mean we’re going to be able to solve a lot of these problems soon." (HorizonXP)
The Cost Barrier and DIY Solutions for Telescope Mounts
A recurring theme is the high cost of commercially available harmonic drive mounts for telescopes, driving interest in DIY solutions.
- "I have experienced the pain of getting ekos/kstars/indi tools to work well on my personal scope." (ddahlen, alluding to the complexity and potential frustration of existing solutions)
- "I considered buying a big harmonic drive mount for my scope, but the cost is really prohibitive." (ddahlen)
- "Just ordered a wave 150i myself. Can’t wait to not having to waste time balancing my scope anymore." (Aaargh20318, referencing a commercial harmonic drive mount)
- "My current mount weighs 40lbs, the counter weight is 17lbs, and the tripod legs are 20lbs. So that's over 75lbs of weight and size of gear to move around every time it goes on a road trip. This design looks like it was a fraction of that." (dylan604, comparing to their existing equipment)
- "I've got a Juwei-17 (Onstep harmonic drive with performance similar to the ZWO AM5N, but at nearly half the price) paired with the ZWO TC4 carbon fibre tripod. ... Alltogether, the setup weighs about 8 kg (18 lbs) since I don't have to use counterweights." (sn0opy, offering a comparison to a more affordable commercial harmonic drive mount)
- "The reason is that Trump is tariffing the hell out of the main Chinese telescope accessories manufacturer, ZWO. So if you can provide a non-Chinese alternative...." (bhouston, suggesting commercial potential for DIY solutions due to geopolitical factors)
Challenges and Triumphs with FreeCAD
Several users discuss their experiences with FreeCAD, acknowledging its power and potential while also lamenting its user experience and occasional instability. The discussion highlights the learning curve and the power of persistent effort.
- "I've been using freeCAD for about 3 years now. Looking at what he was able to make with it blows my mind. I love freeCAD, but I don't think I've ever been so continuously frustrated by a piece of software" (fusslo)
- "Three years should be more than enough time to have learned how to perform a few simple extrusions and pockets. What we're looking at here is essentially a pipe with a cap. Free cad gets really complicated the moment you want to do surface modeling." (imtringued)
- "For real, I've been using FreeCAD for small hobby stuff for 7 years and still often find extremely frustrating UX issues in features new to me, stuff that wouldn't pass QA... This gatekeeping attitude is really off-putting, the project needs a UX expert and a good community manager..." (Klaster_1)
- "Though very grateful for projects like FreeCAD, I did encounter a fair bit of frustration while designing this. Especially random crashes, which only got worse as the project got more complex. As far as usage goes, it's mostly a matter of knowing how to do things in FreeCAD. I haven't encountered anything I could not achieve in FreeCAD." (waerhert)
- "I came to FreeCad with some years background in Inventor, NX and SolidWorks. The jump from any of these to FreeCAD is not very big; you're doing a lot of the same things. But, most of the problems FreeCad has are solved in those, so you can sort of do anything in them and be none the wiser. In FreeCAD, you need to think a little bit more on how it's going to do things." (alnwlsn)
- "I'm not going to agree to any of the "free" (you sign away all rights to the things you made free) tiers. Not that anyone would ever use my things but it's out of principle. FreeCAD has issues but is good enough for most people." (consp)
- "It feels like there is no limit to what can be done. After going through the growing pains of designing stuff that was just poor and difficult to print I’m now confident enough to send it to be printed by jlcpcb or pcbway." (davidhyde, relating their FreeCAD experience to successful manufacturing)
The Value Proposition of Commercial CAD Software (and the "Free" Tier Debate)
Contrastingly, some users advocate for commercial CAD software, particularly Autodesk Fusion 360's free tier for hobbyists, citing efficiency and polish, while others strongly caution against such "free" options due to potential licensing or intellectual property concerns.
- "That said, I recommend Autodesk Fusion free tier for anyone who just wants to get quality work done quickly. Some will refuse to use it on principle and that’s fine for them, but it really is quality software free for hobbyist use with trivial restrictions." (Aurornis)
- "Getting downvoted, presumably for suggesting a non-OSS software to get a job done. However I’d recommend anyone who just wants to get work done at least consider the options at their disposal. Not every software decision needs to be made on principle." (Aurornis)
- "Those who have bought into "free" closed source software simply haven't been burned hot enough by it yet. It might take a while, but you'll learn your lesson one of these days." (nancyminusone)
- "Honestly it’s useful enough that I’d pay the several hundred dollars per year if I had to. It’s that much better. The money spent would be well worth it (for me) for all the time saved over using FreeCAD. I’ve used multiple professional CAD packages and I’m just not interested in going back." (Aurornis)
- "I’m not complaining. Anyone who wants to use a certain software based on principle is free to do so. I’m sharing recommendations from my own experience and that of my peers. If the goal is to focus on the project you’re trying to do instead of fighting with software then people should be aware of their options." (Aurornis)
- "Do you have a source for this? Or are you speculating? ... Great that it works for you. I have limited time for hobbies and I can’t justify making choices based on principle to avoid hypotheticals that even you admit aren’t going to happen." (Aurornis, responding to concerns about signing away rights)
CNC Machining and Manufacturing Services
The ability to easily order custom CNC-milled parts is a point of fascination and a practical enabler for DIY projects.
- "I'm most impressed with being able to order the CNC'ed metal parts. I'm just a novice cad designer and I'd love to learn that capability." (mrgaro)
- "It's super easy actually ! 1) Upload step file, 2) see what's possible: https://jlccnc.com/cnc-machining-quote" (4gotunameagain)
- "Xometry and pcbway are alternatives, among many others" (zokier)
- "I joined my local Maker's Space specifically for the machine shop. ... However, every time I went up there to actually try to build the piece the unit was down... Instead, I wound up using the regular metal working machines to hand make the first piece... I wish I would have known of one of these types of sites to have the piece still CNC'd instead." (dylan604)
- "It's good to be in a place where you're confident things will turn out alright when you send your designs halfway across the world to be manufactured. I've so far only had positive experiences with JLCPCB, especially with issues that turn up during their review process." (waerhert, recounting a positive interaction with JLCPCB)
Astrophotography Software, Techniques, and Equipment
The discussion touches upon the software ecosystem for astronomy, equipment choices, and practical considerations for astrophotography.
- "EKOS already has pretty good scheduling features (I've seen, not used). Along the way I did vibe-code a TUI for controlling the INDI server running on the MeLE 4C minicomputer attached to the telescope..." (waerhert, referencing EKOS/KStars/INDI)
- "Is there any open-source software that calculates where a given planet or star might be (based on your coordinates) and automatically finds the star / planet and then follows it?" (artgship)
- "Sure. Skyfield is a python library to calculate that (among others). Right on the front page is an example how to calculate the azimuth and elevation of Mars: https://rhodesmill.org/skyfield/" (krisoft, recommending Skyfield for astronomical calculations)
- "Stellarium and Kstars (which has EKOS built in) are both very good planetarium software. Both can interface with indiserver, which can talk to many astronomy devices such as mounts, filter wheels, cameras." (waerhert, answering a question about planetarium software and INDI)
- "To me solving the orbits of planets (etc) based solely on my own measurements sounds very compelling. It would be like retracing the steps Kepler etc did." (zokier, envisioning a project for quantitative astrometry)
- "I switch between the cheap Byomic 76/700 newton and my Sigma 600mm lens (Canon EF but using an adapter to fit the Olympus body)... I've since bought a dedicated astro camera (Neptune C II) which fits alright on the newtonian." (waerhert, detailing their equipment)
- "Yeah, in astro, the quality of the lens shows in much more disappointing ways that regular photography. Any softness from the lens can be part of the art in regular photography, but in astro is a lesser image." (dylan604, commenting on lens quality in astrophotography)
- "I’ve been looking into using my 3D printer and electronics know-how to build my way out of this. I was even thinking of swapping the motors for NEMA 17 steppers. Then I stumbled upon PiFinder, and I think this project is going to be the exact balance of automation and Push-to guidance that I would like." (HorizonXP, finding PiFinder as a potential solution)
- "If you hook your ZWO up to Kstars/EKOS you can use plate-solving in software to find out exactly where your scope is pointed at and then adjust accordingly." (waerhert, advising on using KStars/EKOS for plate-solving)
- "I am a bit idly curious since I plan to build a telescope sometime. Nothing as complex as this, just a manually guided dobson." (donkeybeer)
PCB Design and Manufacturing Best Practices
The process of designing and ordering Printed Circuit Boards (PCBs) also emerges as a topic of discussion, with users sharing advice on best practices.
- "I never understood how people learn how to make solid PCBs, I've made a few things but I think I must be missing some decoupling capacitors or resistors or whatever, because my microcontrollers aren't very stable. How do you all just know what stuff to put on the PCB? Do you read the datasheet for the component and add whatever is there?" (stavros)
- "basically every part will provide a minimal schematic in the datasheet or have a reference design you can copy from" (Palomides)
- "Checking the datasheet is essential, they usually show the “must-have” parts around a chip. Beyond that, good habits are adding decoupling caps close to the pins, keeping ground solid, and following the reference layout." (waerhert)
- "Beyond that, use decoupling caps for all power pins, as close to the chip as you can, and make one side of the PCB a ground plane. These 2 things should solve most of your issues." (bongodongobob)
- "On the PCB side, I used a plugin for KiCAD that automatically generates the production files and the bom.csv - It's really critical to review this when you load it into their tool because the automatic recognition/matching with components sometimes has mistakes in it." (waerhert, sharing a tip about KiCAD plugins and BOM generation)
Mount Performance and Accuracy
The accuracy and performance of the custom mount are compared to commercial alternatives.
- "So is the accuracy and stability he achieved better or worse than the commercial mount?" (donkeybeer)
- "Short answer: it's in the same ballpark as other mounts of the same size. The theoretical accuracy for RA is 0.198″ (65,536 steps and 100:1 reduction) and for DEC is 0.253″ (256*200 steps, 100:1). In practice many things will reduce this accuracy: seeing, proper polar alignment, sturdiness of the wedge and tripod all account for some loss in accuracy." (waerhert)
- "So do you think that complex mechanism ended up no better than the normal mounts? It could be execution too, I am no good at experiments and sometimes even "proven" designs end up a bit subpar, so it could be the design was alright." (donkeybeer)
- "Oh ok. I didn't know harmonic drives were standard in commercial mounts." (donkeybeer)