Tag: programming

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 csillagtura.ro/obe. 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. csillagtura.ro/dso 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.

  • 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.


See my github.

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. Nova.astrometry.net 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.

(tovább…)

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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 astrometry.net 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 csillagtura.ro/dso. 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.

(tovább…)

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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. Astrometry.net’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 csillagtura.ro/dso. 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.

(tovább…)

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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…)

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Rosette Nebula (Caldwell 49), 2016-10-16 processing

Rosette Nebula (as processed on 2016-10-16)

Rosette Nebula (as processed on 2016-10-16)

I used the old raw material as described in this post, but this time I used the new program described here. This is the result.

From wikipedia: The Rosette Nebula (NGC 2237, 2238, 2239, and 2246) is a diffuse nebula in Monoceros. It has an overall magnitude of 6.0 and is 4900 light-years from Earth. The Rosette Nebula, over 100 light-years in diameter, has an associated star cluster and possesses many Bok globules in its dark areas. It was independently discovered in the 1880s by Lewis Swift (early 1880s) and Edward Emerson Barnard (1883) as they hunted for comets.

I also looked up the small open cluster on the lower right of the frame, it is NGC 2236. It is about 9600 light years away, ie about twenty times further than the Pleiades.

Canon 1100D mod, obi de 200mm F/2.8 la F/4, 20×150 sec, ISO 800, EQ3, Dângău Mare, Cluj, 2016-04-03

(tovább…)

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Heart and Soul revisited

Heart and Soul nebulae, processed on 2016-10-15

Heart and Soul nebulae, processed on 2016-10-15

In the camp at the Rotunda Pass, my plan was to acquire hours of light on the Heart and Soul, but the sky thought otherwise. I squeezed out about 8 fair exposures, 4 being with good and 4 with decent transparency (ie less contrast). So the instruments: Canon 1100D mod, 8×3 minutes, ISO 1600 at 200mm F/4 on the HEQ5 mount. I reprocessed the picture with the new star removal tool I developed a few days ago.

(tovább…)

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The Gamma Cygni Region revisited

 2016.10.14. gamma cygni 20160815data reprocessed z final

The gamma Cygni region, reprocessed on 2016-10-14

I wasn’t satisfied with the outcome of my star handling program so I rewrote it. The goal was to obtain an image that is as technically accurate as possible, while contains less artifacts and it is more appealing than the original.

I recorded with the Canon 1100D mod 21×150 sec, ISO 1600, with the lens Canon EF 200mm f2.8L II USM dialed to F/4, mounted on the HEQ5. The main feature is the red glow of the ionized hydrogen region around γ Cygni (the brightest star in the frame) with dramatic gaps caused by clouds of dark nebulae. The Crescent Nebula is also there. The object is also known as NGC 6888, Caldwell 27, Sharpless 105, and is a nebula blown by the Wolf-Rayet star WR 136 (HD 192163) expected to go supernova in the next 100k years.

 

(tovább…)

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How I handle the stars

Veil Nebula, about 4 hours

Veil Nebula, about 4 hours

This post is outdated, this is the new article.

A dense starfield can be the amateur astronomer’s nightmare for it can effectively hide the faint nebula behind it. The more errors add up, the less is reveiled of the target. Why? Because the stars that are supposed to be pointlike get big, lens errors blow up the stars, bad seeing blows up the stars, any amount of dew on the lens or fog spoil the stars while the nebula is still there. So I thought of something: what if I could tune the volume of the stars. Another train of thought arose from an image artifact I keep getting – a panda eye like feature, ie a dark ring around the pointlike luminous stars. These two problems amazingly have almost the same solution: throw out the stars and use the remaining context. The point being aesthetics and not science, I started to brew a software.

(tovább…)

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NGC 7000 – third approach

NGC 7000 as I processed it on 2016-09-22

NGC 7000 as I processed it on 2016-09-22

Back in December 2015 my modded camera had the first Ha-enhanced light. As I keep most raws, I dag up those in order to test whether my processing abilities have evolved. One aspect is the healing algorithm I wrote to handle the dense star fields – ie: remove all highlights and their immediate context and fill the holes from the remaining image data. Canon 1100D mod, 20×110 sec, ISO 1600, Canon 200mm f/2.8 lens dialed to f/4.5, EQ3 mount, unguided. More than fairly dark sky of a place near Dangau Mare, Cluj county, Romania.  (tovább…)

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Astrocamp at the Rotunda Pass

Astrocamp

Dark Skies 2016 Astrocamp, Rotunda Pass

Amateur astronomers from Máramarossziget/Sighetu Marmației organized the Dark Skies 2016 Astronomy Camp at the Rotunda Pass. The area is one of the last remaining dark spots in the EU, so dark that the clouds appear to be dark brown/black.

The camp being meant mainly for visual observers, had no electricity, just a generator run in the evening, during the dinner to recharge the gadgets. It is the owner’s fault we had no running water at all, an issue I would have imagined for the savanna/desert in Namibia, not the Romanian countryside with a long estabilished cabin with as much water that my jacket got wet in a clear night. So much for the level of civilisation and decency. (tovább…)

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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.).