alt.hn

6/26/2026 at 7:29:17 AM

Wallace the 6 inch f/2.8 telescope, building it, and hiking with it

 https://lucassifoni.info/blog/hiking-with-wallace/

by chantepierre

6/29/2026 at 8:18:36 PM

Very cool project and video documentation, really inspiring! As someone who is mechanically inclined and has a decent amount of tools/3D printer, is there any DIY telescope that you would recommend to build as a first foray into the field?

I've never done much with optics, and after reading through a few of your posts, it looks both incredibly challenging and very rewarding.

by zonkerdonker

6/29/2026 at 8:28:23 PM

To me, there are two models that stand out from the crowd :

- The Hadley, a 4"1/2 f/9 dobsonian telescope, which is a smaller aperture but easy to build and to find optics for, and very mature : https://www.printables.com/model/224383-astronomical-telesco...

- The "open smallest telescope" from a friend, which I show here, a foldable 6inch f5 dobsonian : https://lucassifoni.info/blog/2025-best-6-inch-f5-150-750-po... and can be found on Printables : https://www.printables.com/model/1325533-ost-open-smallest-t...

Both are very cool projects, the smallest shows more for deep sky but costs a bit more in optics, and the Hadley has a very mature community.

by chantepierre

6/30/2026 at 7:11:42 PM

I will check them out! Thanks for sharing

by zonkerdonker

6/29/2026 at 9:38:28 PM

How into this will you get? If you just want to make your own a small telescope is easiest (see the other reply). As things get large expenses go up. Commercial lens are cheap for smaller telescopes, but as you get to large that becomes the cost and so making your own is the only way you can afford it. If you want a large telescope you should again start making a small one, but this time making your own lens - even though it isn't cost effective to make your own lens (vs buy), the experience means you have a chance to make a larger one (and finish, most people who set out to make one large telescope never finish, those set out to make a small and then a large are more likely to finish both).

If you just want to see the stars, goodwill often has telescopes cheap. A refactor can see more than your eye. (or even the binoculars you likely already have!). And the bigger reflectors are seen once in a while.

by bluGill

6/29/2026 at 10:40:05 PM

I built a Hadley 114 over the course of 3 weekends and I highly enjoyed it. Amazon has a convenient 2 piece mirror kit you can buy. The rest of the parts (springs, screws, rods) can be acquired anywhere and the stand can be as complex or as simple as you want.

by GloriousKoji

6/29/2026 at 11:15:50 PM

Just go down the rabbit hole like I have over the past year...

Find thick glass on Facebook, build a cutting jig, build a kiln to fuse it, etc. I'm still planning to build an 18".

by giantg2

6/30/2026 at 7:14:48 AM

Very nice, are you documenting this somewhere ?

by chantepierre

7/1/2026 at 4:10:03 PM

No, it's nothing new. There are other projects that have documented these types of things better than I could.

by giantg2

6/29/2026 at 9:31:46 PM

Love this. Thanks for sharing. My friend and I pulled an old Dobsonian telescope of my Dad's from the garage when we were teenagers. We spent hours and hours out with it under the stars, and on cloudy nights I would read a book about telescope construction. Back then, cabinet makers were building the most impressive wood frames. Interesting to see how the technology has changed.

by mybbor

6/29/2026 at 9:37:53 PM

> cabinet makers were building the most impressive wood frames

You say impressive, but my mind reads that as heavy even if they looked amazing

by dylan604

6/29/2026 at 10:09:36 PM

Yeah! I meant impressive more in the “big sturdy woodwork” sense, not lightweight. They had to hold a heavy mirror and still move smoothly enough to aim by hand. The Dobsonian design, plus Teflon on Formica bearings, made big aperture amateur telescopes way more accessible to hobbyists. From what I gathered it was definitely a “bigger is better” kind of thing, and weight seemed pretty secondary.

by mybbor

6/30/2026 at 7:14:31 AM

We still do it ! But the designs have evolved, see : https://www.youtube.com/watch?v=SWhxCwHVPms

I'm planning this kind of build for my 16". It's still a dob, still uses teflon against formica and a wood structure, but the ability to move it easily indeed became a desirable feature.

by chantepierre

6/29/2026 at 8:26:50 PM

Quite an impressive build. How hard is it to collimate the telescope? Does it hold the collimation?

by rom16384

6/29/2026 at 8:31:35 PM

Hi ! It is quite easy, with 2 tilt screws at the secondary cage, and the primary cell floats on three heavy duty springs. I can shake it and nothing moves, this is my first criteria. I collimate with a cheshire tool but always finish on a star at medium power (since this telescope realistically does not reach high power, since it would need 2mm eyepieces which are the opposite of wide field views). I use it with Explore Scientific 17mm 92 degree, and a 13mm APM XWA 100 degree eyepieces, and do star collimation with a 6.7mm eyepiece.

So most of the use is at 25x, to frame huge objects like NGC7000 or the largest extensions of M31

by chantepierre

6/29/2026 at 11:14:12 PM

Barlow!?

by helij

6/30/2026 at 1:11:20 AM

Well, I could, but checking collimation at 1-2D magnification for an instrument used at 0.16D provides no observable advantage once star collimation was done. My rule of thumb is to star collimate at a higher power than actually used to observe

by chantepierre

6/29/2026 at 9:00:06 PM

Beautiful, like I needed a new crossover of hobbies; btw could this fill a 220 format frame?

You also could save a lot of weight by boring out your plywood base and still be plenty rigid

by petee

6/30/2026 at 7:15:25 AM

I'm sorry, I did not find what you meant by a 220 format frame. Is it a film photography type ?

by chantepierre

6/30/2026 at 9:03:15 AM

220 is a roll film, essentially the same as 120 film, just a longer roll. It's 6cm wide, and picture format depends on the camera/lens, varying from 6x4.5 up to 6x7 (and beyond, for panoramic shots).

So for use with your telescope, it'd need to produce an image circle that'd cover at least 6cm.

by platinum95

6/30/2026 at 9:32:15 AM

Thanks for the clarification. I don't think so, my largest eyepiece has a field stop of 39mm, and I'm taking advantage of the fact that edge illumination falloff is not perceptible in visual astronomy when the f/D ratio is low.

by chantepierre

6/30/2026 at 11:57:59 AM

Very cool, any pictures of the images it produces?

by thenthenthen

6/30/2026 at 3:07:56 PM

Sadly not as I exclusively practice visual astronomy.

Here is a nebula, NGC7000, drawn by an excellent observer, which appears that way (very wide field, but a bit dimmer than their drawing) :

http://www.astrosurf.com/magnitude78/serge/images/NGC7000_10...

My advantage despite the low diameter is the ability to frame such huge objects !

by chantepierre

6/30/2026 at 7:19:09 PM

What is ‘visual astronomy’? (Sorry, absolute noob here). Wait did you mean.. ‘non-visual astronomy’? I am really confused now

by thenthenthen

7/1/2026 at 11:14:25 AM

I believe he means that he does not do astrophotography. So no photos to share

by lgcmo

6/29/2026 at 10:13:08 PM

Very cool project. Been taking my dwarflab mini on hikes instead of the 12” dob ;) , not the same at all but enjoy getting dark sky and some great astro shots.

by robotswantdata

6/30/2026 at 8:18:45 AM

I want to start looking at the sky with my kids. Would be nice to have something portable like the dwarflab mini. How would you rate it? Does it capture planets in some detail?

by hebrox

6/30/2026 at 4:24:16 PM

Not good for planets IMO as 150mm focal length and a small 30mm aperture. Binoculars or small desktop DOB is better with kids for planets. The mini is amazing for deep sky objects for the price

by robotswantdata

6/29/2026 at 9:43:11 PM

How does one get started in the telescope building hobby?

by oAlbe

6/30/2026 at 12:46:35 AM

I wanted to know as well! The resources I found, though, don't mention anything about what is the safety precautions one should take about the dust generated in the process. What masks to use and such. I understand everything should be done wet, but I wanted to know, for example, if one should wear a mask when polishing with cerium oxide even when wet. Maybe I'm being too cautions of this? I do fear what I don't understand! It's hard to make decisions without numbers. If anyone has any info on this please let me know! :)

by danilor

6/29/2026 at 11:17:29 PM

You might be lucky enough that a local museum regularly hosts a telescope making workshop. In the SF Bay Area you can go to the Chabot Space & Science Center on Fridays 7-10pm.

by hackingonempty

6/29/2026 at 6:24:31 PM

Very nice!!

What are you using for interferometry?

by hackingonempty

6/29/2026 at 8:12:58 PM

Hi, thank you !

I am using DFTFringe ( https://github.com/githubdoe/DFTFringe ) with a Bath interferometer (specifically this model which is super handy : https://www.printables.com/model/986094-multi-bath-interfero... ) and this 3-axis table which is bulky but simple to build ( https://www.printables.com/model/860316-xyz-platform-for-bat... ).

I am also trying to automate the XYZ table, capture and analysis like WavefrontPro does, I have a POC going on that bases itself on a CLI-only build of DFTFringe + outside orchestration with Elixir. My goal would be to control everything with a gamepad and automate the whole test session. Here is a video : ( https://www.youtube.com/watch?v=ii2eGb7vbk4 ). But I need to throw the code away and rewrite it.

by chantepierre