Wednesday 14 September 2022

A possible rarity found on older diamond dust Moon display photos




The several past winters in the Czech Republic were very sub-par. Lots of work and not enough negative NAO resulted in bad conditions across the country.

Since another winter season is behind the door, I wanted to get ready a bit and started looking at older pictures to prepare me for what's ahead.

A quick look at an older diamond dust display from the beginning of 2019 left me speechless. I have found not only Moilanen, but also a possible Mikkilä arc (do we call it that?) as well. Sadly, the display was changing very rapidly and stacking proved to be non helpful. My wide lens is also at the end of its life, resulting in lots and lots of artifacts that makes discerning any low-vis arcs very hard.

Below is an unsharp-masked photo of the arc in question:


  
Apart from Moilanen and the mystery arc, there is a weak helic arc and some nice Lowitz arcs as well.
 
Let me know what you think of this. I'll leave you with a cold-feeling inducing shot of a later stage of the display.
 
 

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7 comments:

  1. Anonymous15 September 2022 at 07:02

    Tried my best at background substraction. Both arcs are nicely visible at the final image.
    https://imgur.com/a/KpSgTNr

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  2. Alec Jones16 September 2022 at 22:20

    Hi Matěj, Great catch, well done! Could you give a rough estimate of how long this arc lasted? Is there any chance you could share some of these images in the sequence so that others in the group could take a look at them? Many thanks!

    ReplyDelete
    Replies
    1. Anonymous19 September 2022 at 13:20

      Hey there Alec, the arc lasted approximately 15 minutes.
      Here are the raw (.NEF) files, you're all free to do anything with it!
      The password is: halovault2022

      https://ulozto.cz/tamhle/SMAvVGrGafHL#!ZJH5AwR2ZmAzMGt5ATRjLwEzLGZkZ0kVMzSMq25HJTEBAwN3ZD==

      The sharing site is in Czech, feel free to contact me if you're having any troubles downloading the files.

      Matěj (Blogspot still has issues with keeping me logged in, that's why I'm commenting as anonymous)

      Delete
  3. Anonymous2 January 2023 at 04:51

    Yeah, this is "Mikkilä arc" there. It is there when the Moilanen arc has taken some distance to the light source. I don't know if there are actually cases where it wouldn't be. That would call for calculating moon elevation in observations.

    In Taivaanvahti this is named Mikkilä arc. But it is yet another case of Finns naming halos after Finns, which is not a proper practise. A person name is an honour that should come from the outside. It could conceivably be Moilanen arc + something, but then Moilanen didn't discover this, so I don't know if that would be right either. In any case I don't think international naming need to follow what's in Taivaanvahti.

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    Replies
    1. Anonymous2 January 2023 at 04:51

      That was M. Riikonen commenting

      Delete
    2. Jari Luomanen29 January 2023 at 19:27

      I agree. While it is nice to know who published what first, we might be better off to let the names emerge (in time) as they may. So long as it is not a name that was not the first one to publish.

      Delete
  4. Jari Luomanen29 January 2023 at 19:26

    This comment has been removed by the author.

    ReplyDelete