5 ms·
The tiniest yet real telescope I've built
- Nition 10mo agoI always love the moment in blog posts like this, where the writer with their esoteric knowledge of the project will say something like "I almost considered reflaboring the exahenge, but of course it would be a ridiculous prospect for a project of this type". And then always, inevitably, there is the followup edit; "I reflabored the exahenge." Too rarely in life are things made better than practical consideration would dictate, just because of dedication to the craft.
- chantepierre 10mo agoYour comment brings me back to my first mirror making adventure, I was absolutely overwhelmed by the jargon and acronyms used by the mirror making community... a few years later I internalized it and use it as if it was common knowledge. I should put little explanations or details in my posts.
- awesome_dude 10mo agoA friend of mine once told me - learning a new field is all about learning the language of that field
- eru 10mo agoThat's a big part of it, but far from everything.
- awesome_dude 10mo agoI'm not really sure - I deliberately stopped there because the concepts related to that field are a part of the language learnings.
- eru 10mo agoIf you are a really big fan of something, you'll get familiar with the lingo, but that doesn't mean you can play StarCraft well or weld or shred your guitar. That's actually part of why FizzBuzz was so notorious: there were (apparently) plenty of people who could talk the talk about programming and software engineering, but couldn't do FizzBuzz.
- awesome_dude 10mo agoYou're right, people write code all day long and have no idea what pattern it is that they've just applied. Having said that, they cannot communicate that that's what they want done, nor can they receive instructions to do something that way. They really are hand in hand.
- eru 10mo ago> You're right, people write code all day long and have no idea what pattern it is that they've just applied. Thanks for agreeing with me, I guess. I was actually making the opposite point: People who can talk about creating software, but who can't actually create any software.
- awesome_dude 10mo agoYes... and I was pointing out that people who think that they can write software... cannot talk about it, making them...? You're completely missing the point that doing and talking are necessary in a world where developers aren't the only ones working on a project. What use is someone that can write a priority queue, but not be able to be asked to write one, or to tell anyone to write one? The same as someone who can ask for those things, but cannot do it themselves... right?
- jiggawatts 10mo agoWhat they hear: "Exorcise the lattice hoard to siphon the new incarnation." What we said: "Purge the web cache to download the new version."
- lukan 10mo agoThat metaphor would here be pretty accurate, though.
- BobaFloutist 10mo agoI think that's probably not an accident.
- macintux 10mo agoA friend of mine asked me why we have such precise terminology in IT; I asked her why English has so many different words for "chair".
- Nition 10mo agoThere was enough there for me to get the basic idea, which is fine I think. Can't really expect every niche post to have all the details necessary for a general audience and it's fun to get a glimpse into these worlds anyway. Thanks for sharing the post!
- aa-jv 10mo agoI just love the fluent use of terms, and the whole ontology of the subject itself just seems so appealing to me. For a moment, I felt like others feel when listening to me and my colleagues discuss kernel build issues or other software challenges - befuddled, bemused, enchanted. I guess, if/when I retire to that remote mountain hideaway, I might just get into this hobby. The idea of grinding my own mirrors to look at dew on the spiderwebs of the neighborhood is just so appealing.
- dekhn 10mo agoHistory is made by people who reflabor the exahenge. I build microscopes instead of telescopes (as a hobby). I can't tell you how many times I've taken a mostly working system and stripped it down to make some important change that affects most of the design to get only a tiny incremental improvement. Sometimes that improvement makes all the difference (for example, being smart when 3d printing a piece that carries something heavy so it doesn't deflect) and sometimes it's just an itch I need to scratch. Eventually, I learned to make two: a microscope that gets built and used, and then a microscope that is a prototype. Then I'm not tempted to take the daily driver and pull the engine.
- taneq 10mo agoWell yes, but are you wiggling the giblet or are you flensing the grobbulus? Because the latter requires specialised equipment and a flensing trampoline, whereas the former requires a 1mm Allen key and possibly a hard whack on a nearby surface while nobody’s looking.
- cadr 10mo agoOoh! Tell us about microscope making as a hobby!
- dekhn 10mo ago
- chantepierre 10mo agoHello, author here ! Other interesting builds or projects going on in the french amateur telescope maker community : - Sunscan, by the STAROS team : a fully integrated open-source solar imaging kit : https://www.sunscan.net/fr - Eric Royer's binocular 24" dobson : http://www.astrosurf.com/topic/124758-bino600/ - The Slim400 by Laurent Bourrasseau : https://www.cloudynights.com/forums/topic/920950-the-slim400/ - Astrowl, an electronically enhanced astronomy kit : http://www.astrosurf.com/topic/151807-projet-astrowl-de-visuel-assist%C3%A9/ - The smallest, an open-source 6" portable dobson : http://www.astrosurf.com/topic/176898-un-dobson-150-f5-facile-%C3%A0-imprimer-et-assez-compact/ - A dedicated astrophotography power supply : https://github.com/Antiath/Open-Power-Box-XXL Of course there are many others but those are the one on the top of my head now
- 9Mfhf34U 10mo agoDo you have an RSS feed just for the astronomy posts on your blog?
- chantepierre 10mo agoNo, but that should be quite straightforward to add with Astro, I will check that. Edit : it seems that I now do have one : https://lucassifoni.info/blog/tag/astronomy/rss.xml I am not an RSS user myself, I tested it with an online reader and it should be working.
- 9Mfhf34U 10mo agoCool, thank you very much. I just tried it, the links don't seem to be working. I get sent to https://lucassifoni.info/miniscope-tiny-telescope.mdx https://lucassifoni.info/miniscope-tiny-telescope.mdx for example
- fransje26 10mo agoThank you for the links and the write-up! I'll share them with a friend who loves astronomy and who loves to organize star-gazing events that he livens up with his Unistellar telescope.
- isolli 10mo agoVery nice! But you won't beat this ;) > Optical Engineer Rik ter Horst shows us how he makes very small telescopes (at home) which are intended for use in micro-satellites. https://www.youtube.com/watch?v=HxwhCmO90UQ https://www.youtube.com/watch?v=HxwhCmO90UQ
- danhau 10mo agoCame here to link this, but you beat me to it :)
- jcims 10mo agoYou both beat me. :D
- chantepierre 10mo agoRik's monolithic Cassegrains are the perfect example of the blend of amateur and high-end professionnal work in astronomical optics, thanks for linking it ! His amateur work is incredible, like this 16" CDK : https://www.cloudynights.com/forums/topic/558284-a-400-mm-f125-telescope-with-integrated-adc/ https://www.cloudynights.com/forums/topic/558284-a-400-mm-f1...
- jiggawatts 10mo agoDayyum, those shots are incredible! I've seen worse pictures from professional telescopes.
- tejtm 10mo agoThis coming year ... if the crik don't rise (as it does with some regularity). Some of you may be able to take a picture of yourself with one of Ril ter Horst lenses as it will be launched in a 2U cubesat named OreSat1 by Oregon's Portland State University undergrads. https://www.oresat.org/home https://www.oresat.org/home pictures would be captured by hand held groundstations https://www.oresat.org/technologies/ground-stations https://www.oresat.org/technologies/ground-stations
- amelius 10mo ago
- ggm 10mo agoWhen did buying a mirror on Ali overtake grinding your own? I guess when Ali became Edmund scientific ie mirror grinding hasn't been a thing since I was in shorts (the 70s)
- chantepierre 10mo agoWe buy pre-dug mirrors on Ali to refigure them, or dig and figure our own all the time. See Ali as a supplier of prepolished blanks :) . The l/6 I mentioned in the post are l/6 spheres, so they also need figuring.
- mapt 10mo agoMirror grinding is still a thing. Just not a thing that young people generally do. Distribution got easier and real estate got more scarce. Those of us who have garages, have filled them up. In my understanding it's gotten considerably easier over the years with better availability of diamond and CBN abrasives, and with more electronic control of the grinding hardware. Slumping glass and bonding a thin sheet to ceramic foam reduced the costs and weight a great deal as well. Mastering these techniques make it easy to start a small business rather than to do a one-off in your garage, though. As a sidenote: The Celestron RASA astrographs are so effective and so inexpensive of a wide-field instrument that it's a lot harder to justify the DIY activity that existed in the 2000's.
- chantepierre 10mo agoThere is quite a vibrant community of young people grinding mirrors, it just has displaced to Discord. The "Observational astronomy" discord server has a lot of late-teenagers and young adults grinding. Our french Astro-FR server has people in their thirties grinding. But as you pointed out, garages are sparse and people seem to take shortcuts : finding bad pre-polished mirrors as blanks, slumping glass sheets to shape and continuing with fine grinding...
- buescher 10mo agoIf you just want a serviceable telescope, you haven't been able to really save any money by grinding a mirror for decades, unless you're a madman like Dobson who scrounged blanks in the form of things like porthole windows. But that's not why people do it. I haven't built a non-trivial telescope but it is not too unusual for amateur telescope makers to figure mirrors to precision that you can't easily buy, i.e. not for amateur prices. Where he talks about Ali mirrors being l/6 or better? That's really good for randomly buying something unspecified cheap on Ali. l/6 is lambda/6 which means the surface error of the mirror is less than 1/6 a wavelength of light. Utility optics are typically l/4. Really fine stuff is l/10 or l/20.
- upvotenow 10mo ago[flagged]
- 2b3a51 10mo agoRoughly similar in size to the ones Newton made for the Royal Society as demonstration instruments. https://en.wikipedia.org/wiki/Newton%27s_reflector https://en.wikipedia.org/wiki/Newton%27s_reflector Very nice and I might look for one of these mirror kits.
- LtdJorge 10mo agoVery cool blog, not just post
- chantepierre 10mo agoThanks, it's heartwarming. It's my current longest living attempt at a blog
- seanrrr 10mo agoVery cool project! I always wanted a telescope as a kid but kind of forgot about that desire as an adult. Didn’t know you could build your own like this.
- chantepierre 10mo agoIf you want to commit to a build, this one is thought to be user-friendly and a great first instrument : https://www.printables.com/model/1325533-smallest-telescope-kit-for-150750 https://www.printables.com/model/1325533-smallest-telescope-...
- seanrrr 10mo agoThank you! Will check it out!
- clusterhacks 10mo agoWatch your local craigslist or facebook marketplace. With a little patience, you will probably find a good 8" or 10" dobsonian at a great price. I picked up a lovely 8" dob for less than $200. Most of the generic 8" F/6 dobsonians seem pretty decent. Or check your local library. It may have a smaller Starblast table-top dobsonian you can check out - I did that when traveling once. Whatever you do, do NOT buy a small cheap refractor on some flimsy mount. They are mostly awful.
- bluGill 10mo agoThere are a lot of DIY telescopes out there. I suggest you spend several days reading about what others have done (and why). Start with an easy build to prove you can - people who get something small done are much more likely to finish a larger telescope, so start small as a practice run.
- ramblin_ray 10mo agoNice!! I printed a very similar (but larger) telescope back in 2018 with similar results... I didn't research my mirrors well and ended up with bad ones. Plus, it wasn't very stable at that size. I'd imagine a smaller version would be much more stable... Thanks for sharing!! https://yesteryearforever.xyz/ABSDBS https://yesteryearforever.xyz/ABSDBS
- chantepierre 10mo agoThis is the first time I've seen a build of the ABSDBS in the wild, thanks for sharing ! Sadly an 8" f/4 mirror has a very narrow range of acceptable optical quality :/. It's too bad you ended up with a bad one. Maybe refiguring it would be a great followup project though
- jimnotgym 10mo agoWhat I got from this is: If you want a working telescope for $small, buy a second hand one. If you want to mess around with mirrors for hours on end then build one!
- chantepierre 10mo agoAbsolutely, second hand is the most direct path to getting a telescope.
- tgtweak 10mo agoSo what are these tiny portable ones? I always assumed they were digitally augmented or virtual even - is there a minimum size for it to be a "real" telescope?
- chantepierre 10mo agoThis one is a bit of a joke with my telescope making friends, but ticks all the boxes of what I consider a real telescope. You can actually buy 76mm entry-level telescopes, but they often have an unstable mount and bad optics. Starting at 150mm, you already have a lot of punch under dark skies. Visual use, live digitally enhanced, or astrophotography are 3 different hobbies.
- err4nt 10mo agoSo cool! Thanks for sharing. It reminds me of one of those very old cameras with the bellows or accordion. I wish I could look through it myself to see what you see with it!
- chantepierre 10mo agoThis article gives great impressions of what you can see with your eyes through various sizes of telescopes : https://www.deepskywatch.com/Articles/what-can-i-see-through-telescope.html https://www.deepskywatch.com/Articles/what-can-i-see-through...
- groos 10mo agoExcellent. I might have a go at this myself. Was there a particular AliExpress seller that you got the mirror from?
- chantepierre 10mo agoHi, I could send you the link but as outlined in the post, this specific mirror was very out of tolerance..
- groos 10mo agoI looked but AliExpress makes it impossible to locate even specific sellers, like BohrOptics, who I found to have consistently good quality (bought a beam splitter and fused silica ball lenses from them).