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Re: [vsx-dis] MISAO

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  • Arne Henden
    Obviously, I m a little confused here. For example, #52 may have few data points, but it has nearly 2 magnitudes variation, and the images are pretty clear as
    Message 1 of 13 , Sep 2, 2006
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      Obviously, I'm a little confused here. For example, #52 may have few
      data points,
      but it has nearly 2 magnitudes variation, and the images are pretty clear as to
      which star is variable and by how much. They are even from the same observer.
      Are you saying this is not a variable? Or are you saying that you
      want a minimum
      amount of information, such as a complete light curve and period
      analysis, before
      any star is considered variable? It certainly meets your amplitude > 2-3 sigma
      criteria. So what do you mean by very questionable? I'm not debating with you,
      just trying to understand your concern. 64 is similar, and is linked
      to V1174 Sco.
      I didn't look further into your list.
      Arne

      On 9/2/06, martin_piers_nicholson <martin_piers_nicholson@...> wrote:
      > As a way to greatly speed the process.
      >
      > Ask the experts to generate a list of the MISAO variables not
      > currently linked to a GCVS entry.
      >
      > Better still do this concentrating on those south of -30.
      >
      > You will find most, if not all, of these are very questionable.
      >
      >
      > MISAO 50-100 but not in GCVS
      >
      > Very questionable
      > 52
      > 56
      > 59
      > 64
      >
    • martin_piers_nicholson
      Take Misao 98 as an example. BAD NEWS Only 2 data points, March and June 1999. However to my eye quite a few other stars in the field look different as well.
      Message 2 of 13 , Sep 2, 2006
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        Take Misao 98 as an example.

        BAD NEWS
        Only 2 data points, March and June 1999.

        However to my eye quite a few other stars in the field look
        different as well.

        GCVS didn't include it although it appears in the same issue of IBVS
        as many MISAO stars that were accepted.


        GOOD NEWS
        They differ by a quoted 1.1 magnitudes and the photos clearly show
        the indicated star has changed in brightness.



        What I would like is clear guidance on what constitutes proof of
        sufficient quality and quantity to qualify for inclusion in VSX. If
        I were to invest time in going through the material it would have to
        be on the basis of having this framework in place first. (Refer to
        forthcoming email on priorities in this context)
      • kawai.sasami
        ... You have evidently not read up on or learnt about or taken note of the pixy system and its subsequent revised form the pixy2 system. If you had you would
        Message 3 of 13 , Sep 3, 2006
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          --- In vsx-dis@yahoogroups.com, "martin_piers_nicholson"
          <martin_piers_nicholson@...> wrote:
          >
          > Take Misao 98 as an example.
          >
          > BAD NEWS
          > Only 2 data points, March and June 1999.
          >
          > However to my eye quite a few other stars in the field look
          > different as well.

          You have evidently not read up on or learnt about or taken note of the
          pixy system and its subsequent revised form the pixy2 system.

          If you had you would know that differences between brightnesses
          between discordant images are allowed for, correction can be applied
          given the reasonable assumption that the vast majority of the field
          stars are constant. Once this form of calibration has been applied
          any remaining difference in magnitude found for any particular star
          has a likelihood of being variability, the large the amplitude, the
          higher the likelihood.

          As most images were unfiltered highish amplitude red LPVs were
          predominantly detected in the MISAO system.

          Incidentally, I am not part of and never was part of MISAO and I shall
          note that separately.

          > GCVS didn't include it although it appears in the same issue of IBVS
          > as many MISAO stars that were accepted.
          >
          >
          > GOOD NEWS
          > They differ by a quoted 1.1 magnitudes and the photos clearly show
          > the indicated star has changed in brightness.

          they were measured, reduced, to show this. Not guessed by eyeball.
          Granted the photometric calibration is against USNO A2.0 red mags, so
          the magnitudes are purely MISAOing, but that's the way it was.

          The original intent was to find incidental asteroids in spare images.
          PIXY and any presumable precursor thus had to match any and all
          images to the USNO A2.0 catalogue to find new objects that shouldn't
          be in the field. Some level of magnitude estimate is also useful for
          such endeavours, and A2.0 at the time, and still now to some extent,
          is the only readily available bulk system allowing stars to fainter
          mags than most amateur imaging. ie Seiichi has a copy. Although I
          vaguely remember PIXY2 could fetch other data off of the net later on.

          All form memory, all stuff I learnt by bothering to read the MISAO
          website in the past.

          John
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