Magyar menüt kérek. Show menu in Hungarian

Tag: programozás

Some of my projects

(I write in English for convenience)

  • OpenBabel.Erdély, a Romanian-Hungarian Dictionary, useful for Hungarians living in Romania. It incorporates general usage words, institution names and expressions specific to public life, locality names and toponyms in general. I recommend the web gui Details on this page. OBE is also available as integrated into an editor, the obe-wordpad.I consider maintaining this dictionary a duty towards my community.

  • DSO browser - has a database of more than 200k deep sky objects, able to show their realtime apparent position on the sky from the location of the observer, and estimates imageability based on altitude, overall brightness, surface brightness, distance from the Sun and from the Moon etc. uses the obe frontend, so it can be invoked from it using the :dso search argument, like NGC 7000 :dso, but the night mode /dso is the interface I recommend. I use the DSO integrated into csillagtura's wordpress to aid me with writing articles. It also has an object marking utility, which I will expose later.

  • Aladin to Photo Planner - it builds on the Aladin Lite API and visualization and on DSO to help plan astrophotos, including mosaics.

  • Polaris - for polar alignment
    In amateur astronomy a short but very important task is to correctly polar align the telescope's mount. My Polaris "app" is a visual aid to do just that.

  • StarHeal - in astrophotography
    A program to handle dense star fields on astrophotographs, sometimes I call it starheal but doesn't really have a name.

  • the putzolo
    A userscript to tweek facebook's interface.

  • my personal web browser: around a WebView, I built the subset of a web browser I need for a less annoying experience on my phone: it has both java-level and javascript-level adblocking built in, and gets rid, at least on the pages I visit, of the annoying gdpr and other popups.

  • the Soapbox project - guiding my telescope
    I put together a little piece of hardware, based on an Arduino, to give commands to the mount, through the ST4 port it exposes - even if no such port is exposed, like in the case of my old EQ3 mount. The whole device resides in a soapbox, hence the name. It receives commands from the desktop, which runs another piece of the puzzle, an app that tracks stuff on the live view displayed in the recording software. As an extra, the soapbox also drives the motorized focuser, be that through buttons, a joystick or an encoder, of which the last one is my favorite so far. The encoder itself has its own Arduino, can be used as a standalone device, or as an extension to the Soapbox, hooked up in a daisy chain, to receive serial commands from the PC.

  • the filterwheel automation -- related to the soapbox project above, I motorized an otherwise manual filter wheel.

See my github -- though I don't really update it.

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)



Photoplanner: Close Neighbors

So I’ve been thinking about this: what if I want target proposals for objects that have a nearby neighbor. Like the Double Cluster, or  M81 and M82, or M35 and NGC 2158. So I came up with a generic filter in the photo planner that narrows the search results based on whether a particular result has a neighbor. The search switch is conjunction, and the unit is degrees, defaulting to 1 degree. Some searches (like an unpolite naked :conjunction) may still result in a server error (low memory), so the switch works on already specific queries.


Galaxies that have an obvious nearby friend:

type:galaxy minlum:11 conjunction:1

Open clusters and/or globular clusters that are near each other:

type:ogc :conjunction

Open or globular clusters or planetary nebulae with at least one planetary nebula in the pair. The curious cases of M46 and NGC 2818:

type:pnogc conjunction:0.7 conjunctiontype:pn minsize:0.005

The results are some pretty nice vistas.



My photo planner

a print from my planner

A few month back I ran into problems trying to identify certain deep sky objects that showed up on my pictures. Stellarium – although I like it – is good at searching for known objects, and not by coordinate search, and I cannot script it the way I want. is also a very useful tool, but it does not have all the objects I grew able to image. I built my own deep sky database, a strong search tool, but that one is a search tool only with no visual sky, although I linked it to Aladin Lite. Aladin and Simbad – I like them, but they lack an easy coordinate search – and I really mean easy when I say so. Obviously, Aladin and Simbad are mainly for professionals, I guess. Stellarium has a photo planning feature, but – even though it can show Aladin’s sky, still no button by default -, it doesn’t fit my hands. So I felt like everything I need is out there somewhere, but the dots are just not connected.

I wanted to have all my knowledge at my fingertips, everywhere, and finally to have a robust output, that doesn’t fail when going offline: paper. Needless to say, my thoughts converged towards a website.

So I wrote my own photo planner, based on the Aladin Lite API and my DSO search engine and Simbad’s coordinate search.



Mélyég-adatbázis a csillagtúrán

A DSO felület éjszakai üzemmódot használ

Észrevettem, miközben közreadáshoz készítettem elő a fotóimat, hogy azok máris mélyebbek, mint amilyen mélyre a legtöbb program megy.

A Stellariumnak megvannak az erős és a gyenge oldalai is. Az keresője (angolul plate solving) szintén korlátok között mozog. A Simbad adatbázis és az  Aladin böngésző asztali és web változata egyaránt gazdag kincsesbányája az asztrofotósnak, az asztali változatban a mozgó egér alatti objektumot kikeresi és mutatja például. Ezt a web változat is igazán tudhatná, de nem tudja sajnos (lennebb a javítása). A gyengéje, hogy mintha valós időben készítené elő az égboltot lefedő képeket, így elég lassú. De különben is, valami kézhezállóbbat szerettem volna.

Ezért készült a Azt hiszem, hadilábon állok a programjaim elnevezésével :P. Találtam githubon ezt az adatbázist, bő kétszázezer objektummal. A fotóimhoz jó ideig kellően mély lesz ez az adatbázis. A CSV fájlt SQL adatbázisba emeltem, az objektumok elnevezését pedig jelentősen bővítettem angol és magyar nyelven, illetve behelyeztem néhány román nevet is. Aztán megírtam egy erős keresőfelületet, amely szinte minden szempont szerint ki tudja ásni az adatbázisból a keresett objektumokat. És ami fontos: kúpkeresést is tud, egy objektum vagy egy adott koordináta környezetében. Hozzáadtam még egy virtuális égbolt funkciót: a látogató GPS-e alapján a program az objektumok látszó magasságát és óraszögét is kiszámolja.



DSO database on my Csillagtúra

A printscreen of the UI. It uses night mode.

While posting my pictures, and describing the photographed objects, I noticed they are already deeper than most of the shallow catalogs and softwares go. Stellarium has its strengths but also its weaknesses.’s plate solver also has its limits. The database behind Simbad and the Aladin viewer their website has embedded is great in many ways – on the desktop edition I can point with the mouse, and the pointer’s coordinates get resolved into an object, but no such feature in the web version (I added it, see below). A weakness is that both the web version and the desktop edition are slow to render the sky, I wonder whether they have any caching or the tiles are morphed real time. Anyway,  I wanted something more personal, integrated into my website.

So I made I think I am bad at naming my programs :P. I found this database on github, with more than 200k objects. This database should cover my deeper photographs for a long time. I converted the CSV into an SQL, and extended it with popular names for objects mainly in English, many in Hungarian and some in Romanian. I also added functionalities like search by virtually any aspect of an object, and, very important: cone search around each result, or just a cone search around some coordinates. I also added some virtual sky features: based on UTC time and the visitor’s gps coordinates retrieved from the browser, my program also calculates the objects’ alt-az coordinates.



StarHeal – how I handle the dense star fields

Left: the original. Right: the automated output: less prominent stars, no panda eyes.

The Milky Way offers some great wide angle views for the astrophotographer. But there is a catch: the dense star field. While in theory stars are point like, ie subpixel sized, in practice the seeing, some worse than ideal transparency, lens errors, bad focus, a not that parallel lens and sensor, a bit of dew – all work against the astrophotographer.

While I can’t solve all the problems, I sure can try. So I wrote a program. I found that I can mitigate some of the problems: the blown up stars, the panda eye image artifact around stars with middle range luminosity and the overall visual impact of the star field. I continued to develop the previous version of my software, so here’s what I’ve got now.

The program

I wrote the program in PHP because it is the language I mainly use. It is not the best choice, by far. But it does the job I expect it to do. All you need is a webserver, some storage space, memory and time. You may download it from here. (tovább…)


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.).