T CrB Light Curves

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Hi Newbie here. I generated this 500 day T CrB Light Curve graph and wondered if someone could explain the different colored “frequencies” are. I assume the number in brackets is the number of data points. In particular, what is the upside down black triangle “faint” plot ? TY.

Sorry I could not just attach the plot. Here are the data points :
All (335128) : Open Circle (7421) Vis, Black Triangle (1124) Faint, Black Star（108995) B, Green box (106791) V, Red Diamond 15420) R, Purple Hex（10657) I, Oval（1116) U, Pink Diamond（1）J, Green Diamond (1) H, White Asterisk in Green square (14332) CV, White Asterisk in Purple square（348）CR, White Asterisk in Purple circle (15767) TB, and White Square in circle (35379)

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Hi @pamanners

The different symbols represent different bandpasses of light. They are produced by placing filters in the optical chain.

First, there are visual observations which are non-standard because everyone’s eyes are a little different, but they are remarkably close:

  • Vis - Visual observations taken by eye with or without additional optics (binocular, telescope).
  • Faint (downward triangle) - Visual observations where the object is “fainter than” the reported measurement value.

Then there are observations which have standardized filters

  • UBVRI - Observations taken with Johnsons U, B, V; or Cousins R, I filters and reduced against standard stars in the corresponding reference system.
  • CV - Observations taken with a “clear” filter reduced against Johnson’s V reference frame.
  • CR - Observations taken with a “clear” filter reduced against Cousin’s R reference frame.
  • ugrizy - Observations taken with a Sloan ugriz and reduced against standard stars in the corresponding reference system.
  • JH - Mauna Kea Observatory Near-infrared J or H bands and reduced against standard stars in the corresponding reference system.

There are also a few non-standard filters:

  • TG, TR, TB - Are tri-color Green, Red, or Blue respectively. These are typically produced using color cameras. Compared to the bandpasses mentioned above, TG, TR, and TB are not standardized. For example, Green in some front-side illuminated CMOS cameras is fairly similar to the bandpass of Johnson V, but it will admit around 50% more light, mostly on the blue and red ends of Johnson V. In the case of newer deep photosite back-side-illuminated CMOS sensors, Green can end up being more like Johnson V + Cousins R + Cousins I. TG, TR, and TB data are typically reduced against Johnson V, Cousins R, and Johnson B respectively, but reported as TG, TR, and TB due to their significant differences from the reference standard.

Kind regards,
Brian

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Thank you VERY much Brian. Excellent summary and explanation, and understood well thank you.

I will be keeping my own running data watch, with screen shots, to monitor T CrB’s changes and hopefully “big show” !

Best regards,
Paul