Hallo Mark,
heut nacht hab ich mal die rote Brille aufgehabt:
Man sieht so gut wie nichts...
Auch die Sterne nicht, Schwan, Deneb war damit nicht sichtbar.
Angenehm, weil blendfrei war die Mondbetrachtung. Da wars ein
Vorteil. Aber sonst, zu dunkel.
Nun ist das ne Rotbrille fuer zehn Mark.
Fuer Teleskope gibt es spezielle Rotfilter.
Die sind teuer, aber auf eine ganz spezielle Frequenz abgestimmt.
Damit waere wohl eine bessere PL- Wahrnehmung visuell zu erreichen...
Grus Peter
Fuer Mark: Rotlichtbrille...
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jan lameer
Re: Fuer Mark: Rotlichtbrille...
Hi Peter and Mark
It is an interesting idea to use filters visually for observing aurora. Basically aurora has sharp green and red frequencies, so if you could find a filter that transmits those two frequencies of light and throws out city lights, I think you could see aurora in cities better. It should throw out sodium (natrium) orange street lights and those sorts of lights.
The fact that you don't see stars with a red filter is because A our eyes are not very sensitive for red light (only 15 % or so compared to yellow-green light) and B because many stars don't emit much red light. Betelgeuse, Arcturus and Aldebaran should be visible though.
But I think finding a really dark location is the only way to see aurora well. I've done a few observations last year in October and November from the Dutch mainland and I am afraid to say that those observations were disappointing compared to what I've seen on the island of Terschelling with perfect dark views to the north. The pics were good (still have to be published on my site) but visually it was no fun. After one or two hours it feels like being in a shopping mall: lights everywhere. And also so many fumes and human made clouds...
Nothing beats a true dark location with clean air for observing aurora. In Germany there are still many places that are darker than our Dutch darkest spot (I hope!).
greetings, JanL
It is an interesting idea to use filters visually for observing aurora. Basically aurora has sharp green and red frequencies, so if you could find a filter that transmits those two frequencies of light and throws out city lights, I think you could see aurora in cities better. It should throw out sodium (natrium) orange street lights and those sorts of lights.
The fact that you don't see stars with a red filter is because A our eyes are not very sensitive for red light (only 15 % or so compared to yellow-green light) and B because many stars don't emit much red light. Betelgeuse, Arcturus and Aldebaran should be visible though.
But I think finding a really dark location is the only way to see aurora well. I've done a few observations last year in October and November from the Dutch mainland and I am afraid to say that those observations were disappointing compared to what I've seen on the island of Terschelling with perfect dark views to the north. The pics were good (still have to be published on my site) but visually it was no fun. After one or two hours it feels like being in a shopping mall: lights everywhere. And also so many fumes and human made clouds...
Nothing beats a true dark location with clean air for observing aurora. In Germany there are still many places that are darker than our Dutch darkest spot (I hope!).
greetings, JanL
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Peter Wloch
Re: Welchen Helligkeitswert haben Auroras?
Welche Helligkeit haben eigentlich die Auroras ?
Also, auf uns in D bezogen: Die Rote vom 22.Oktober z.B.
hat wohl jeder gesehen.
Ich schaetze die mal auf scheinbare Helligkeit 2.00,
dann gibts noch die fotografische Helligkeit...
Wer weiss genaueres?
Gruss Peter
Also, auf uns in D bezogen: Die Rote vom 22.Oktober z.B.
hat wohl jeder gesehen.
Ich schaetze die mal auf scheinbare Helligkeit 2.00,
dann gibts noch die fotografische Helligkeit...
Wer weiss genaueres?
Gruss Peter
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