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If you are looking for the more professional side of me, you may take a look at my Publications (see below) or head directly to my work homepage: Dr. Birte Kristina Friesel @ Universität Osnabrück
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Contact
You can reach me by E-Mail (derf@finalrewind.org) and on IRC (derf0 @ OFTC, hackint). My PGP key for E-Mail encryption is 64FE6EC0 55560F9E F13A3044 19E6E524 EBB177BA. I occasionally post stuff on the Fediverse (@derf@social.skyshaper.org).
The remainder of this page duplicates a curated sub-set of projects and the latest blog entries.
Projects
> dbris 'Eichlinghofen H-Bahn, Dortmund' 'Dortmund Hbf' 19.01. 16:51 (00:21) 17:12 . Bus S Bus 440 → Oespel S-Bahnhof, Dortmund 16:51 (+1) ab Eichlinghofen H-Bahn, Dortmund 16:56 (+1) an Oespel S-Bahnhof, Dortmund Fußweg 46m (≈ 3 min.) S 1 → Dortmund Hbf . 17:01 (+5) ab Dortmund-Oespel 2 17:12 (+2) an Dortmund Hbf 7
> hafas 'Eichlinghofen H-Bahn, Dortmund' 'Dortmund Hbf' 00:15 Schw-B HB5 (0:03) S 1 Schw-B HB5 → Universität S-Bahnhof, Dortmund 21:51 ab Eichlinghofen H-Bahn, Dortmund 21:55 an Universität S-Bahnhof, Dortmund Walk 37m (approx. 3 minutes) S 1 → Dortmund Hbf 21:58 ab Dortmund Universität: 2 22:06 an Dortmund Hbf: 4
> efa Essen Martinstr Düsseldorf Hbf 14:34 ab Essen Martinstr.: Bstg. 1 Straßenbahn 108 Essen Altenessen Bf Schleife 14:38 an Essen Hauptbahnhof: Bstg. 1 14:47 ab Essen Hauptbahnhof: 2 R-Bahn RE11 (RRX) Düsseldorf Hbf 15:24 an Düsseldorf Hbf: 10
> dbris-m 'Bochum Hbf' 06:39 ( +7) ICE 843 Berlin Hbf 5 06:39 ( +7) ICE 853 Berlin Hbf 5 06:51 (+19) S 1 Essen Hbf 7 06:37 ( +1) ICE 527 München Hbf 3 Zug fährt abweichend mit nur einem Zugteil. Die Wagen 31 - 39 entfallen.
> hafas-m 'Hamburg Dammtor' 13:49 ( +1) RE 7 Flensburg 3 13:49 ( +1) RE 7 Kiel Hbf 3 13:49 S 5 Buxtehude 2 13:50 ( +4) Bus 5 Nedderfeld, Hamburg 13:50 U 1 Ohlstedt, Hamburg
> efa-m -s VVO Dresden Hbf 13:40 ( -2) 5 66 Lockwitz 13:41 3 3 . Wilder Mann 13:44 4 3 . Coschütz 13:44 6 66 Freital-Deuben 13:46 ( +4) 6 360 Kurort Altenberg Bahnhof 13:46 5 360 Dresden Ammonstraße / Budapester Straße 13:48 ( +1) 1 7 * Weixdorf 13:51 1 10 . Tolkewitz 13:52 Gl.10 RE3 Hof Hbf
News
Tatry day 3: Through the Northern Foothills and Sarnia Skała
This is a post about our 2026 vacation in the Tatras (Tatry), see Hiking vacation in the Tatra Mountains for an overview.
There was pleasant weather with a rain and thunderstorm warning, so we decided to play it safe and stick to the (relatively) low northern foothills of the Western Tatra. On the one hand, we would be surrounded by higher peaks and vegetation in there, and on the other hand, we would be able to leave the national park (relatively) quickly in case of inclement weather. The last thing you want to do during a thunderstorm is climb a peak and be a human lightning rod, after all – plus, the stones in the Tatra mountains can be pretty slippery when wet, which is a good recipe for getting hurt (Western Tatras) or dying (High Tatras).
Today's trip would lead us across three ridges / peaks and three valleys, with a total elevation gain of about 1,000m spread across three ≈300m climbs.
We enterd the national park around 10:00 via Kuźnice, as usual, and followed Droga Brata Alberta as on the first day. However, shortly before Kalatówki, we took Ścieżka nad Reglami (Pfad über den Riegeln) and headed due west up Biała Czubka (DE). It offered us a nice view of the cable car up Kasprowy Wierch and Długi Giewont, whose southern side we had passed two days before.
We descended into Dolina Sucha Giewoncka only to climb back up the next ridge, where we found a short path up Sarnia Skała (DE). It was pretty packed, but looked promising, so we made a detour there and, after waiting in line for a while to let other hikers leave the rocky outcrop that is Sarnia Skała, made it there. It's definitely worth a visit – Sarnia Skała was full, but not overly so, and we had good views not just towards Zakopane and Długi Giewont, but also a considerable part of the Western Tatras that we had traversed on the days before.
We returned to Ścieżka nad Reglami and kept following it down into Dolina Strążyska, which held a hut selling ice cream, hot and cold drinks, and other refreshments. We used this opportunity for a break before we embarked on the third and final 300-and-something m climb of the day, this time up Przełęcz w Grzybowcu. The trail and the surrounding mouuntainside were, once again, pretty steep.
Once atop the saddle, we could have headed south towards Kondracka Przełęcz – it would have been just 300 more metres of evelation with mostly low incline. However, on the one hand, we had already been there, and on the other hand, the clouds that had been forming throughout the day started dispensing rain just as we reached the saddle. We also heard thunder in the distance, so we thought it best to head down into the next valley and then leave the Tatras.
As anticipated, the rocks had grown slippery, but not overly so. Combined with a low angle of descent and the fact that we were right at the edge of the rainclouds, the path remained about as safe as it had been. We did not have to get out our umbrellas, and soon enough, the sun peeked through the clouds again. Had we been a few more km to the southeast, we probably would have had a different experience.
Once in Wielka Polana Małołącka, we left Ścieżka nad Reglami and headed north through Dolina Małej Łąki, thus exiting the national park. This segment was still nice to walk though, but of course less spectacular than the ridge-and-valley sequence we had going on before.
We left the national park around 17:30, walked along its northern edge for about 2 km, and then headed into Zakopane for dinner. More photos can be found at lib.finalrewind.org/Sarnia Skała 2026.
Tatry day 2: At the Foot of the High Tatras
This is a post about our 2026 vacation in the Tatras (Tatry), see Hiking vacation in the Tatra Mountains for an overview.
We had another day with good hiking weather in front of us – not as sunny as before, but still warm and dry. So, we decided to head out a bit further to the east, albeit with a slightly tamer route: a stroll through Hala Gąsienicowa (Gąsienic-Alm) and its mountain lakes, where the highest point would be Mały Kościelec (Kleiner Kirchberg) at just 1,866m of elevation. This would bring us right to the edge of the High Tatras (Hohe Tatra) and their rather harsh mountainside – on the day before, we had only traversed the considerably calmer Western Tatras (Westtatra).
Again, we started at around 10:00, entering the Tatra national park in Kuźnice as on the day before. This time, we headed east, traversing the Boczań and Skupniów Upłaz ridges (which we had already seen from afar when making our descent on the day before) as well as the Królowy Grzbiet ridge. This time, the steepest ascent was right at the start of the trip: 500m across 3 km, so still far less demanding than on the day before.
We reached Hala Gąsienicowa (Gąsienic-Alm) at 13:30. It is located in the upper parts of Dolina Suchej Wody (Trockenbachtal / Valley of Dry Water), sloped along a respectable 1,400 to 1,700m of elevation. We also got rather close to Schronisko PTTK „Murowaniec” na Hali Gąsienicowej (Murowaniec-Hütte), which would have offered toilets, food, drink, and shelter. We had no need for any of those and therefore passed it by without a visit.
After a short break, we started a round trip through Dolina Gąsienicowa (Gąsienica-Tal, possibly also known as Seealmtal) that would eventually lead us back to the trail through which we had entered it, passing several streams and mountain lakes as well as one (relatively small) side ridge of the High Tatras in the process. The vegetation already grew lower and sparser, indicating that, even though we were on a meadow, we were definitely in the mountains and nearing the tree line. And, since we were in a meadow, this section of the trip was relatively even – so we could walk rather fast and have more time for breaks whenever the scenere seemed suitable.
First off, we followed an unnamed stream uphill, passing Mokra Jama (Feuchtes Loch) as well as a crossroads (and, later, a chairlift) that offered a direct path onto the eastmost part of the main ridge of the High Tatras. However, we stayed in the valley, following the stream towards Litworowy Staw Gąsienicowy and then Zielony Staw Gąsienicowy. Here, we took another break until about 15:00, and were also slightly delayed due to a phone call – yes, you do have pretty good mobile and 5G reception in this valley.
Before we could climb Mały Kościelec, we had to pass between three more (smaller) lakes: Wyżni Czerwony Stawek, Niżni Czerwony Stawek, and Kurtkowiec. To our (but not its) surprise, we saw a deer, which caused significant delay to us and a bunch of other hikers. The deer did not care about the many camera lenses pointed at it, and simply went about its business.
Next, we made the ascent towards Mały Kościelec, arriving on its peak / ridge at about 16:00. The ground changed to medium-sized boulders, some of which were thankfully laid out in a reasonably even path. We had a nice view back onto the lakes, up towards Kościelec (Kirchberg, which we did not climb), and also saw a hint of snow and ice in the distance. There wasn't much left, though, and especially not on the peaks.
Once atop Mały Kościelec, we could look back at yesterday's destination, Kasprowy Wierch. The ridge itself was rather small, and offered a prime view of Czarny Staw Gąsienicowy (Schwarzer Gąsienicowa-See).
The descent towards the lake was rated SAC T3, indicating challenging mountain hiking. Indeed, we had to pass not just nicely laid-out stones, but also quite a lot of steep, loose rubble that looked more like the remnants of a stone avalanche than a hiking trail. We nearly missed the bend towards a better trail segment and wondered whether we should follow the rubble for a bit longer. In any case, once at Czarny Staw Gąsienicowy (around 17:00), we could take another break and enjoy its clear, cold water. Unknown to us, we also had a prime view of the ridge that is home to Orla Perć (Adlerpfad / Eagle's Path), which we would pass by a few days later.
The return to Hala Gąsienicowa and Królowy Grzbiet, which we reached by 18:00, was uneventful. Proper trees returned, indicating that we were slowly descending.
However, we did not return to Zakopane via Skupniów Upłaz and Boczań, taking Siodłowa Perć into Dolina Jaworzynka instead. The descent was steep, but pretty scenic, and the valley also offered a last view towards the harsher side of Skupniów Upłaz.
We returned to Zakopane by 19:30, just in time for lunch, having traversed 18 km with a total ascent of 1,050m. Again, we made plenty of breaks and took a total of 9 hours the trip.
Since we had sufficient time to spare, we decided to head towards the centre of Zakopane, and found a very nice swiss restaurant: Mała Szwajcaria (“little switzerland”) at Hr. Władysława Zamoyskiego 11. It offered a cozy setting, excellent Swiss food (at non-swiss prices, too), good Czech beer, and a tasty dessert on top. We chose Bernese Rösti as main dish, and made a mental note to return on a later day for some Fondue.
More photos can be found at lib.finalrewind.org/Mały Kościelec 2026.
This is a post about our 2026 vacation in the Tatras (Tatry), see Hiking vacation in the Tatra Mountains for an overview.
For our first full day in the Tatras, we decided to hike along the main ridge of the Western Tatras: from Kopa Kondracka / Kondratova kopa (DE / EN) to Kasprowy Wierch (Kaspars Kogel). In order to do so, we had to climb from 960m to 2,000m, and then back down along a different route. And all of that with a weather forecast of nearly 30°C – so we made sure to bring plenty of water and minerals with us, and were looking forward to comfortable 20-something °C on the ridge.
We headed out at around 10:00, entering TPN at 10:30-ish via Kuźnice (DE). It's the largest and closest entrance in the vicinity of Zakopane, served by several bus lines, and also houses the lower station of the cable car to Kasprowy Wierch. As such, the paths were quite full, but the crowds slowly dispersed as we made our way towards Kondracka Przełęcz (Kondratovo sedlo / Kondrat saddle).
The first five kilometers to Schronisko PTTK Hala Kondratowa (Kondrat meadow hut) were pretty relaxed, with broad paths and just 400m of elevation gain in total. We could already glean some views along the local valleys, forests, and nearby mountains, but apart from that, there's not much to say.
Schronisko PTTK Hala Kondratowa offered toilets (with a pretty long queue), ice cream, and some more nutritious food as well. In our case, we simply rested for a bit before continuing towards the next stretch at 12:30: the much steeper and narrower ascent from Polana Kondratowa (Kondrat meadow) to our first real intermediate goal: Kondracka Przełęcz. We were far from the only ones making the ascent, which was hardly surprising given that we were right in the middle of Polish summer holidays. Still, at this point, we were no longer surrounded by crowds – just a bunch of fellow hikers. We slowly made our way up, gaining another 400m of elevation over just 1.5-or-so km of trail.
We reached the saddle at 13:45, and took another photo, food, and hydration break. The views were already very nice, despite this not even being the main ridge of the Western Tatras. We could examine the valley through which we had made our ascent, the footills west of Zakopane, and – way in the distance – the observatory atop Kasprowy Wierch. We also had a good view of the nearby Wielki Giewont (1,894 m) (Großer Giewont / Great Giewont), which was so crowded that we decided not to take a detour onto its peak.
We continued towards Kopa Kondracka at 14:30 or so, and reached it (and the Polish–Slovak border) around 15:30. This time, we had 300m of ascent over about 1.5km of trail, so it was slightly easier going. The low highland vegetation slowly gave way to nothing, and the views kept getting better.
Atop Kopa Kondracka, it was time for our obligatory “cats sitting on border stones and making stupid faces” photo shoot (and a selfie with the camera placed on the border stone) – and of course, time to examine the Slovak side of the Tatras, which we had not seen before. We could also already see the ridge line (and border stones) that we would pass in order to get to Kasprowy Wierch (second picture below)
From this point on, we spent the next hours hopping between Poland and Slovakia, enjoying the afternoon sun in our back and the views into the valleys on either side of the ridge line. Occasionally, we would wind up below the ridge, essentially walking through a meadow sloped at a 45° angle.
The trail had one climbing element with hand-holds, and one without that was not actually meant to be hiked across – I just ended up there because I didn't see the marks on that side of the rocky outcrop. Nevertheless, it was fun, and we also got to see a goat that was decidedly better at hopping across the rocks than we were.
We reached Kasprowy Wierch at 18:00, briefly looked down into the valley that we would be traversing on the following day, and then started the descent back to Kuźnice. We chose the direct route that zig-zagged along Sucha Czuba (DE) and also frequently crossed paths with the cable car Kuźnice – Kasprowy Wierch. Initially, we meandered across (more or less loose) rocks with little vegetation around us, but eventually, we got back the forested areas of the Western Tatras.
We got back to Zakopane Bystry at about 20:00, and ventured into town for dinner. In total, this trip with its 20 km of horizontal and 1,380m of vertical travel and lots of photo breaks took us about 10 hours. More photos at lib.finalrewind.org/Kopa Kondracka 2026.
Tatry day 0: Nosal (nose)
This is the first of a series of posts about our 2026 vacation in the Tatras (Tatry), see Hiking vacation in the Tatra Mountains for an overview.
On arrival day, we got to our holiday home at around 17:30, with pleasant weather and still about three hours of evening sun left. So, since we had spent most of the day sitting in trains, we took the opportunity for a quick first hike: to the top of Nosal (loosely translates as “nose” / “Nase”, situated at 1,300m of evelation) and back. It was just 1.5km to the peak of Nosal, so we expected that we would be back after about an hour, depending on how many photo breaks we took. This assumption would turn out to be pretty optimistic: those 1.5km feature a 750m segment with 250m of ascent, which is definitely not something that we could just shrug off at our typical walking speed of 5 to 6 km/h.
We left at around 18:30 and headed to the nearest TPN entrance, which was no longer staffed due to the late hour. From this point on, we already got a taste of what the Tatras had to offer: the entire trail was pretty steep and it also featured a small (and easy) climbing segment early on, which we had not experienced in Krkonoše (Giant Mountains). It also already offered some nice views down onto eastern Zakopane, Rów Podtatrzański (Sub-Tatra trench / Untertatragraben) in which it is located, Pogórze Spisko-Gubałowskie (Zips-Gubałówka-Vorgebirge / Spisko-Gubałowskie highlands) on the northern side of Zakopane, and towards one of the local tourist attractions: Wielki Giewont (1,894 m) (Großer Giewont / Great Giewont).
The trail remained steep and uneven, and we also took plenty of photo breaks before reaching the peak at around 19:30. From there, we had a good outlook over the Western Tatras, and all the trails and ridge lines that we would be traversing over the next week. In the photos below, the clouds are touching the ridge line – luckily, on the days where we hiked across it, we had either clear skies or a much higher cloud cover. We could also see Kuźnice, which would be our entrance into and/or exit from the national park on several days – and the cable car, which we would end up taking on our most ambitious hike during the vacation, going all the way from Morskie Oko to Kasprowy Wierch while passing Świnica and getting a glimpse of Orla Perć along the way. But that's something for a future blog post.
We left the national park at around 20:30, which was a tad later than planned: we had not had dinner yet, and most restaurants in Zakopane (and especially the few in our vicinity) close at 21:00 or 22:00. Luckily, Karczma Przy Mlynie was both close to our home and open until 22:00, so we could enjoy some Pierogi and beer to round off the day. Plus, the sunset offered some nice photo opportunities.
More photos are available at lib.finalrewind.org/Nosal 2026.
Travel::Status::MOTIS v0.07
Travel-Status-MOTIS-0.07.tar.gz (signature)
- MOTIS: Support window parameter for departure results (patch by networkException)
- MOTIS::Trip: Remove redundancy between
->display_nameand->trip_short_name
Travel::Status::DE::DBRIS v0.15
Travel-Status-DE-DBRIS-0.15.tar.gz (signature)
- Work around latest Akamai BMP TLS fingerprinting rules
Travel::Status::MOTIS v0.06
Travel-Status-MOTIS-0.06.tar.gz (signature)
- MOTIS::Trip: really add
->trip_short_nameaccessor (0.05 only made it available as->{trip_short_name})
Travel::Status::DE::DBRIS v0.36
Travel-Status-DE-DBRIS-0.36.tar.gz (signature)
- Work around latest Akamai BMP TLS fingerprinting rules
- Update rolling stock models and train names (Lili Urban)
Travel::Status::MOTIS v0.05
Travel-Status-MOTIS-0.05.tar.gz (signature)
- MOTIS::Trip: add
->trip_short_nameaccessor (patch by Kenneth Bruen)
Travel::Routing::DE::DBRIS v0.14
Travel-Routing-DE-DBRIS-0.14.tar.gz (signature)
- dbris: handle pseudo-trains withuot occupancy
- Now also compatible with IO::Uncompress::Brotli 0.004_001, as shipped by Debian's current stable release (Trixie / 13)
Travel::Status::DE::DBRIS v0.35
Travel-Status-DE-DBRIS-0.35.tar.gz (signature)
- Adjust unbro call to be compatible with IO::Uncompress::Brotli 0.004_001, as shipped by Debian's current stable release (Trixie / Debian 13)
- Update rolling stock models and train names (provided by Lili Urban)
Travel::Routing::DE::VRR v2.25
Travel-Routing-DE-VRR-2.25.tar.gz (signature)
- efa: Support
efa <from> <to>in addition toefa <from-city> <from-stop> <to-city> <to-stop>. Some backends work much better with this mode. - efa: prepend a quick glance (date/item, duration, lines) to connections
- New backend service: NWL
Travel::Status::DE::VRR v3.21
Travel-Status-DE-VRR-3.21.tar.gz (signature)
- Update BEG backend URL
Travel::Status::DE::DBRIS v0.34
Travel-Status-DE-DBRIS-0.34.tar.gz (signature)
- Update rolling stock models and train names (patches by Lili Urban)
Travel::Status::DE::DBRIS v0.33
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- Formation: Catch invalid UIC IDs before parsing