The tiniest yet real telescope I've built

(lucassifoni.info)

266 points | by chantepierre 2 days ago ago

24 comments

  • chantepierre 2 days ago ago

    Hello, 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
    • hrldcpr 2 days ago ago

      clickable links in case it's helpful for anyone:

      - 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-visu...

      - The smallest, an open-source 6" portable dobson : http://www.astrosurf.com/topic/176898-un-dobson-150-f5-facil...

      - A dedicated astrophotography power supply : https://github.com/Antiath/Open-Power-Box-XXL

    • 9Mfhf34U 2 days ago ago

      Do you have an RSS feed just for the astronomy posts on your blog?

      • chantepierre 2 days ago ago

        No, 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.
    • fransje26 2 days ago ago

      Thank 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.

    • waerhert 2 days ago ago

      Very cool, thanks for sharing! Any ideas of adding 2 gimbal motors to this for GOTO? MS6010v3 or something lighter would seem like a good fit.

    • aidenn0 2 days ago ago

      You wrote up "of course I refigured it" as if refiguring mirrors is something any reader would know how to do. I (and I suspect most of HN) does not; have you (or others) written on this topic?

      • chantepierre 2 days ago ago

        Sure ! Here are a few links :

        https://stellafane.org/stellafane-main/tm/index.html

        How to make a telescope, by Jean Texerau, which was the absolute bible of this field : https://rexresearch1.com/AstronomyTelescopesLibrary/HowMakeT...

        Here is a talk (in french, but maybe the auto-subtitling would work?) I recorded that overviews the whole process (2h30 though, and lacks info on the Bath) : https://www.youtube.com/watch?v=Wt7lBLS0ueg

        Here is Gordon Waite's youtube channel which actually shows a lot of the moves : https://www.youtube.com/@GordonWaite/videos

        Best resource on the Bath (french, but should translate well) : https://gap47.astrosurf.com/index.php/technique/optique-inst...

        • clusterhacks 2 days ago ago

          Wow, thanks for the link to Texerau. I had no idea a pdf was floating around and have wanted this book for some time. You video looks interesting, especially the part around Ronchi and Focault testing. I have 'Understanding Focault' but have to admit that reading it doesn't give me confidence.

          One question I always think about is how much time and effort a "one-time" mirror maker should plan on making to exceed the quality of a generic 8" or 10" F/5-F/7 available from the Chinese mirror makers.

          Zambuto seems to imply that whatever magic happens for his mirrors might be in very long, machine driven polishing to smooth out the final surface imperfections that cause scatter. With his retirement and with few mirror makers in the US, it seems like options for buying "high end" mirrors in the 6"- 10" size are very limited. I have been debating an 8" F/7 and would love to just purchase a relatively high quality mirror, but most of the mirror makers seem more taken with significantly larger mirrors.

        • aidenn0 2 days ago ago

          Merci!

      • groos 2 days ago ago

        I'm sure he didn't explain it because almost nobody knows what it is (or even how to interpret the interferograms he showed) and learning to figure optics takes years and entire books are written on the subject.

  • Nition 2 days ago ago

    I 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.

  • isolli 2 days ago ago

    Very 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

  • 2b3a51 2 days ago ago

    Roughly similar in size to the ones Newton made for the Royal Society as demonstration instruments.

    https://en.wikipedia.org/wiki/Newton%27s_reflector

    Very nice and I might look for one of these mirror kits.

  • ramblin_ray 2 days ago ago

    Nice!! 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

  • ggm 2 days ago ago

    When 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)

  • err4nt 2 days ago ago

    So 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!

  • tgtweak 2 days ago ago

    So 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?

  • seanrrr 2 days ago ago

    Very 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.

  • jimnotgym 2 days ago ago

    What 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!

  • LtdJorge 2 days ago ago

    Very cool blog, not just post

  • groos 2 days ago ago

    Excellent. I might have a go at this myself. Was there a particular AliExpress seller that you got the mirror from?

  • upvotenow 2 days ago ago

    [flagged]