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Tag: programming

The Spectral Composer

I’ve been photographing the Sun for more than two years now almost each and every day, in a bit of a hackish way: using all kinds of filters beyond the 540nm continuum – hydrogen alpha – near UV calcium triad. However, as I advanced, I discovered that this knowledge is simply not common in the community, and not just that, it’s also a bit hard to come by while googling around. Also, to better explain double stacking, off banding and similar stuff, articles like this one Altair Astro’s 3nm CaK Ultra filter: testing, comparison, review are maybe rare.

So I put together an interactive tool to play around with spectra, in a way amateur astronomers find it interesting. The Spectral Composer.


My Old EQ3 with a New Hand Controller

The main piece of hardware, along with its testing devices

So here’s the problem: I like redundancy and I like control, fine grained, precise control of my devices. These are obviously not the aspects that drove me to choose the EQ3 mount when purchasing it, but since it is the mount I have at hand, and no physical room nor real opportunity for something better, I decided to hack this mount.

Independently of Hernán De Angelis who looks like he did a great job, from the same starting point — so kudos –, I got my hands dirty and my screen full of code. (tovább…)


My OBS keyboard – source code

So the whole thing is made in Arduino, one Attiny85 board acting as a USB client, a HID keyboard, and another board, a Nano (ATMega 328P) on the lookout for button presses. The two communicate via serial.

And the source code is published on github here (the USB-handling attiny85) and here (and the buttons-handling nano).

Below is the very first, unoptimized implementation, barely fitting onto the flash.



Moto-focuser for my MC 102/1300

Using my home standard, with the focusing controller mounted into a white box (not to be confused with the soapbox project, which is the auto-guider, also a home standard interfacing with the ST4 on the mount), this is the last tube of mine to be motorized. While the solution leaves no room for one’s head, unless a snail… the solution should work well for planetary photo.


Fotótervező 7. rész: a hasonló a hasonlót vonzza


Let’s Do Exoplanets

A simulated planetary transit, with the associated light curve

An amateur astronomer colleague of mine, Mátyás SZŰCS, got me inspired to look into exoplanets — once again. I already had a close encounter with distant solar systems, while looking into the Kepler measurements as published on the planethunters org website, going through some 4k stars of interest, of the some 160k that Kepler observed during its first mission.

I’ve never done observations of this kind before, maybe I never will. But I wanted to see what it is I could expect. I put together a naive simulation and then looked up some professional material to check for those into such stuff.

So I went for a rather naive approach here, went for numeric simulations in… well, PHP… with a color (rgb) selective limb darkening and planets with no atmosphere. The stars are simple, spherical, no polar brightening and no flattening, as with say Vega.

The interesting thing is the sharp drop between the first and second contacts and then the steady drop till the maximum — see below.




The Chess Clock

chess clock

Showing a 5+0 setup, 5 minutes main time with zero increment

At the end of this stupid year, ravaged by GovId-19 too, not just by covid-19, I put together a chess clock. Even though the number of people I can play with physically is really limited — obviously not everyone thinks, like me, that a calculated risk is worth a decent amount of freedom, poor old BF with who does or does not deserve what exactly — I just wanted to put together the clock, cause why not. Although it is a microsoft site, I published the project on github.

One thing a friend of mine noted: the lunch box… I find it one of the greatest challenges about home made gadgets to find the right box for them, without the 3d printer black magic. I also wanted this one to be transparent.

Another thing, more of a philosophical nature: the more I play around with arduinos, the more I realize how much effort went into the whole thing to be easy like a toy, instead of the PITA it could have been, to enable one to really create on top of an abstraction layer, in contrast with such mindfucks as that of  manually calculating the value of a register to attain a baudrate on some obscure microcontroller I ran into at work, because libraries, because bootstrapping, and because it’s the business logic we are focused on, not reinventing the wheels of bit counting. Really, it’s almost 2021.



Estimating the length of planetary videos

There’s a legend among amateur astronomers that, without derotation, Jupiter supports only 90 seconds of raw video. Anything above it: derotate.

It always felt fishy to me, even before I started doing planetary photography. Due to other reasons, like capturing the moons’ movement, and the interplay of shadows, I always tried to keep the videos short.

However, the subject is evergreen wherever there are newcomers. So, now I made the math, and since we are people, not mathboys, here’s a handy little table one can play with or scroll below, the same calculator loads into this article.



My Filterwheel Automation

Quite some time has passed since I automated my manual filter wheel, so now I write the article. I built this one mainly for fun, I could afford the (overpriced) automated version.

The specifications behind the whole idea

  • automate the manual filterwheel — without modifying the wheel itself, revert the changes should I get bored or if anything goes south
  • make it fail gracefully: the DC motor can be driven by anything outputting around 5V, a manual H-bridge and a couple of AAA batteries for example. Experience: the first version with the encoder failed due to the intense sunlight — hence duct tape and a paper cover of the window were added. Failing gracefully meant disconnecting the logic and connecting the manual H-bridge. No observation wasted.
  • make it compatible with my existing gear (the soapbox and the noszogtató)



My encoder based focuser

So after I built a focuser controlled by a joystick, and considered it a usability failure, I built one based on an encoder, and modified the soapbox accordingly, maintaining backward compatibility. This encoder based hand controller has its own arduino, and connects to the soapbox, and through it to the PC to receive commands from the desktop app — but this connection is optional, it is fully functional as a standalone device. Below is the block diagram, explaining how it optionally fits into the soapbox daisy chain. Most variables are hand tuned for the DC motor + reductor gear box in use, as the source code reveals.



Jól kalibrált monitoron mindegyik számnál elkülönülő árnyalat látszik. Ha mégsem látszanak, akkor a megjelenített képek színhiányosan rajzolódnak ki. A monitort valószínűleg kalibrálni kell.

You should see distinct shades for each number. If those shades are not clearly visible, the displayed pictures will lack accuracy. Your display most likely needs to be calibrated (brightness, gamma, contrast etc.).