Geminids 2013

Geminids appear every year in mid-December, peaking around December 14th, when Earth passes through a stream of debris from comet 3200 Phaethon. Typically more than 100 meteors per hour stream out of the radiant in the constellation Gemini.

This year’s peak of the Geminid meteor shower was unfavourable because of nearly full Moon, that reduced the number of visible meteors. On the day of the maximum activity, between Moonset and dawn, there was a brief window of good visibility. During two hours of observing meteors, I caught about 25 of them on camera. Here is a selection of the brightest.

Geminid, 14. December, 03:34 UT
Nikon D3000, Tokina 11-16mm@11mm, f/2.8, ISO 1600, 53s
Geminid in the middle of the zodiacal light, 14. December, 03:58 UT
Nikon D3000, Tokina 11-16mm@11mm, f/2.8, ISO 1600, 79s
Geminid, 14. December, 04:34 UT
Nikon D3000, Tokina 11-16mm@11mm, f/2.8, ISO 1600, 68s
Geminid, 14. December, 04:58 UT
Nikon D3000, Tokina 11-16mm@11mm, f/2.8, ISO 1600, 33s
Probably not Geminid, maybe Dec. Leonis Minorid, 14. December, 05:10 UT
Nikon D3000, Tokina 11-16mm@11mm, f/2.8, ISO 1600, 24s

Na meji nevidnega

On Saturday 28. new Slovenian science fiction convention was held in Ljubljana for the first time. I was pleasantly surprised over the participation, as there was, most of the time, present at least 100 people.

Convention hall.

Different science fiction, board game, roleplaying related societies presented their activities. There were a sections dedicated to playing Magic the Gathering, Warhammer and painting Warhammer figures. Of course, event like this needs cosplaying performance. Award for the best costume was won by the Witch King (LotR – Lord of the Nazgul), followed by Morgana (LoL champion) costume with moving wings. As befits sci-fi event we even saw Princess Leila slave costume.

Witch King versus Demon Huntress, playing Warhammer.
Magic section.

During the convention, there were lectures with various topics. Artistic society presented the process of making their Witch King costume. From ideas and design to their actual implementation. There was a discussion about problems of translating personal names in books and maintaining their relevance to the content.

LARP-ing equipment.

Thanks to the organizers for promoting events of that kind.
More pictures in gallery.

Sunspots on 23 September 2013

Object: Sunspot AR1846
Date: 23 September 2013 11:35 UT
Equipment: Basler acA640-100gm, GSO 200/1200 + 2x barlow
Capture and processing : FireCapture, AutoStakkert2, RegiStax6
Object: Sunspot AR1846
Date: 23 September 2013 11:50 UT
Equipment: Basler acA640-100gm, GSO 200/1200
Capture and processing : FireCapture, AutoStakkert2, RegiStax6
Object: Sunspot AR1849
Date: 23 September 2013 12:10 UT
Equipment: Basler acA640-100gm, GSO 200/1200 + 2x barlow
Capture and processing : FireCapture, AutoStakkert2, RegiStax6

Programmable ATtiny IR remote

My Nikon DSLR camera does not have any internal programmable mode for continuous shooting (intervalometer) or socket in which wired remote shutter could be plugged in. The only way you can make exposures longer than 30 second is using IR remote. If you want to take only a few pictures, this is not a problem. But when you want to make a time lapse few hours long or photograph a meteor shower for whole night, this is no longer convenient. Especially when you want exposures to have the same length and the same interval between them, this can be very challenging.

That is why I took one of those cheap IR remotes and upgraded it using small ATtiny85 microcontroller. Its task is to simulate button presses depending on the settings of the DIP switch. The element in use consists of five switches. The first one (1) is used for selecting the operation mode. When switched ON continuous mode is selected and long exposure mode when it is turned OFF. Other four switches (5-2) determine the length of exposure or interval. You can change the settings during exposition, but they are not taken into account until the next exposition.

Front panel with ATtiny, DIP switch, MOS N-FET and power plug

Long exposure options – DIP switch 1 is set to OFF:

  • DIP switch 2 ⇒ 10 min
  • DIP switch 3 ⇒ 5 min
  • DIP switch 4 ⇒ 2 min
  • DIP switch 5 ⇒ 1 min

Total maximum time for a long exposure, when all switches are turned ON, is 18 minutes.

Continuous shooting (intervalometer) mode options – DIP switch 1 is set to ON:

  • DIP switch 2 ⇒ 120 s
  • DIP switch 3 ⇒ 60 s
  • DIP switch 4 ⇒ 30 s
  • DIP switch 5 ⇒ 10 s

Total maximum interval between two exposures in continuous shooting mode, when all switches are turned ON, is 240 seconds.

Back panel with voltage regulator and original IR remote

Button presses are simulated using MOS N-FET 2N7000 transistor (see the bottom image for wiring diagram). When pin 1 goes to HIGH the transistor opens and concludes an electric circuit that provides power to IR remote circuit.

Wiring diagram

The similar thing can be build without the whole IR remote circuit using only IR LED diode and microcontroller as output wave generator.

Nova Delphini 2013

Nova Delphini 2013 shining at estimated magnitude of +6.7, 29. August 2013 at 20:30UT. The image shows constellations of Sagitta and Delphini which are near the nova indicated by the cross.
Equipment: Nikon D3000, Nikorr 18-55 @ 55mm, f/5.6, ISO1600, 8s

Bright new nova or “new star” was discovered on 14. August in the constellation of the Delphinus. At the time of the discovery it was shinning at the magnitude of the +6.8 and brightened to magnitude +4.4 in few days after it was first seen in the sky. This easily puts it in the reach of the binoculars and for the observers under sufficiently dark sky it is observable by naked eyes.

Perseids 2013

This year’s maximum of the Perseids meteor shower was very favourable for observing. With no moon and clear weather we were able to photograph and visually observe meteors for several consecutive days. Here are some pictures of the best and brightest meteors caught.

Perseid, 12 August 2013, 23:42 UT
Perseid, 12 August 2013, 22:51 UT
Perseid, 12 August 2013, 22:07 UT
Perseid, 12 August 2013, 20:04 UT
Perseid, 6 August 2013, 23:18 UT