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chantepierre

440 karmajoined il y a 4 ans
meet.hn/city/44.4051354,1.4447979/Cahors

Socials: - https://turing-express.fr

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- https://lucassifoni.info/

Submissions

Building an Unbeatable Mechanical 3D Printed Tic-Tac-Toe Computer [video]

youtube.com
1 points·by chantepierre·il y a 11 jours·0 comments

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

lucassifoni.info
153 points·by chantepierre·il y a 15 jours·33 comments

A worm in my Erlang cluster, and adventures in microfluidics

lucassifoni.info
14 points·by chantepierre·le mois dernier·0 comments

The tiniest yet real telescope I've built

lucassifoni.info
272 points·by chantepierre·il y a 7 mois·72 comments

comments

chantepierre
·il y a 11 jours·discuss
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 !
chantepierre
·il y a 11 jours·discuss
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.
chantepierre
·il y a 11 jours·discuss
I'm sorry, I did not find what you meant by a 220 format frame. Is it a film photography type ?
chantepierre
·il y a 11 jours·discuss
Very nice, are you documenting this somewhere ?
chantepierre
·il y a 11 jours·discuss
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.
chantepierre
·il y a 11 jours·discuss
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
chantepierre
·il y a 12 jours·discuss
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
chantepierre
·il y a 12 jours·discuss
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.
chantepierre
·il y a 12 jours·discuss
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.
chantepierre
·il y a 14 jours·discuss
After this year's Paris marathon, I ran the same per-minute graphs, and they match perfectly the "overall study" graphs with more than 9 million finishes in the article. I also added graphing by age category and gender. I don't want to deduce too much but I think it showed that young men are the most "competitive" (what I mean by that is targeting a specific time) since there are the clearest "goal time" peaks in the graphs.
chantepierre
·il y a 15 jours·discuss
There is no rest. There is just (properly done) a continuous output from start to finish, or a very slight increase of output (negative splitting), but effort to maintain it feels exponential. In terms of feeling, it’s a 32km « dynamic run » where you should feel good, then the hardest 10k you can pull off just after that. If paced properly there should not be a « wall » but at all levels you pass people walking who disintegrated around 30km. Even people with sub-elite/elite bibs sometimes explode.

A half is more intense but way easier, you’re just sub threshold but for a time short enough that you cannot really not make it.
chantepierre
·il y a 16 jours·discuss
Yeah you're right, I hear it more like "this is a week long hike, not a sprint" as if a marathon included rest. In any length of racing there's no tomorrow. But I'm doing tongue-in-cheek pedanticness here and will stop that right now !
chantepierre
·il y a 16 jours·discuss
It makes me smile when runners use "X is a marathon, not a sprint" to hint at an effort that accumulates over time and an optimal use of energy.

I do it too because it's a common expression, and a marathon is of course longer than a sprint, but both have in common that properly raced, they are absolutely brutal efforts that leave you without a single additional drop at the end. The effort length and instantaneous power output changes, of course. Maybe "it's a marathon build, not the race" would be more precise at the loss of nearly all its expressive power (but with a lot more pedanticism points) :-p .

Nice project !
chantepierre
·il y a 26 jours·discuss
"German mode" is an interesting idea !
chantepierre
·le mois dernier·discuss
I routinely use "load bearing" in conversations and writing, both seriously and ironically (like a "load bearing just" or "load bearing paint").. maybe I should stop.
chantepierre
·il y a 2 mois·discuss
I felt that but find it worked way better by invoking it with `claude --effort max` only
chantepierre
·il y a 3 mois·discuss
The hydrogel textures (not maurten but naak, but close enough), for me, allow while racing to swallow a full 40g gel in half a second without feeling the sugary taste a lot, which is nice. Compared to thick syrup-like gels, it’s a way better experience in a marathon.

But I only buy for actual races, rest of the time, I do my own 1:0.8 mix with a bit of thickener, in soft flasks. Much more cost effective.
chantepierre
·il y a 4 mois·discuss
Converting an app that started per-client deploy, single-tenant, cloud-ignorant and mono-node to multi-tenant, multi-node, cloud storage and a cluster of a few nodes.

On one hand, I regret not having thought it could find a market and I now have to do this and plan a migration.

On the other, I saved a lot of time going to customers instead of building the boring side first... So I don't know what to think of it.

I find that most of the development work is now "ops" instead of user-facing features (either addition, removal, or polish) and am a bit perplex at this.
chantepierre
·il y a 4 mois·discuss
Here is a 6in f/5 travel truss dob kit by my friend :

https://www.printables.com/model/1325533-smallest-telescope-...

Wallace, my 6” f/2.8 :

https://www.printables.com/model/997327-wallace-6-f28-telesc...

And my tiny but mighty 3” f/4 : https://www.printables.com/model/1475113-76300-pocket-dobson

Wallace is built, but Gromit, a 16.5” F/3, is under progress. Working on the mirror and CAD :)
chantepierre
·il y a 7 mois·discuss
Re : running relaxed, it is said that the real marathon is the training you put in, and the race itself should feel like a celebration. I am not anywhere near elite level but felt that for a lot of races. The hardships of the training enables a state of deep calm, joy and feeling like you are flying the morning of the actual race. Nights before races are often very bad, like a last storm before everything clears and your mind is finally empty when you get into the corral. Then, with a clear mind, you proceed to run with joy despite being physically tired by the training and sleepless night.