Observing comet 21P/Giacobini-Zinner from the city center of Berlin proved to be challenging. I put up my 130 mm Newton telescope in the living room to catch a glimpse of Capella above the roof of the adjacent building around 3 am on Sept. 5. Not far from Capella, 21P/Giacobini-Zinner was barely visible, but a 10s exposure with the smartphone camera revealed the fuzzy coma of the comet. Since the comet is close to perihelion it moves swiftly across the stars within 1 hour, as seen in the 3 frames animation from my observations at 02:39, 03:04 and 03:14 local time.
It would be nice to knock out the street light or to block the city lights, but it turns out the new LED street lights are emitting with a broad spectrum across to the entire visible range.
I analyzed the spectra with a hand-build spectrometer from Astromedia to evaluate if a UHC filter might help, but unfortunately this is not the case.
The hopes are high for Christmas comet 46P/Wirtanen to be much brighter and better visible at the end of the year.
Wirtanen gets this time very close to Earth (0.071 AU, no danger of collision though) and will be extensively studied. For an overview of our professional work about comet 67P/Churyumov-Gerasimenko have a look at this ZIB feature.
Current comet light curves are compiled on the excellent COBS.SI webpage.