BVRIJHK Photometry: What Do the Letters Stand For?

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Discussion Overview

The discussion centers around the meaning of the letters in the term "BVRIJHK" as used in photometry, specifically within the context of the Johnson photometric system. Participants seek clarification on the definitions of the letters and the process of applying filters in photometric measurements.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that the letters refer to specific wavebands in the Johnson photometric system, ordered by increasing wavelength, with the first four being optical and the last three infrared.
  • One participant expresses uncertainty about the definition of the term "1.00" in relation to filter reflectance, questioning if it indicates the filter with the highest value.
  • Another participant suggests that the table referenced indicates relative reflectance of an object across different bands, though they note the term is not explicitly defined.

Areas of Agreement / Disagreement

Participants generally agree on the basic interpretation of the letters in "BVRIJHK" but there is uncertainty regarding the specific definitions and implications of the reflectance values associated with the filters.

Contextual Notes

There is a lack of explicit definitions for terms used in the discussion, particularly regarding the reflectance values and the process of applying filters in photometry.

tony873004
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What do the letters stand for? Blue, Violet, Red, Indego?

Does anyone have a link explaining the process? Google only seems to give articles describing results from using the technique without explaining what the technique is.
 
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tony873004 said:
What do the letters stand for? Blue, Violet, Red, Indego?

The quick and dirty answer is that those letters refer to specific wavebands in Johnson photometric systems. They run in order of increasing wavelength. The first four are optical wavebands and the last three are infrared ones. More information here:

http://www.starlink.rl.ac.uk/star/docs/sc6.htx/node10.html"


Does anyone have a link explaining the process? Google only seems to give articles describing results from using the technique without explaining what the technique is.

What process are you referring to exactly? The process of applying filters?
 
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Thanks, ST.

The quick and dirty answer and that link was all I needed :smile: . I was reading the journal on the discovery of 2003UB313. ( http://arxiv.org/abs/astro-ph/0508633 ) Based on the context I had a good idea what this was, but I had never heard of it and didn't know what bands the letters represented.

It states that the brightness is highest through the R and I filters, each with a relative reflectance of 1.00. Am I correct to assume that whatever filter gives the highest value will be considered to be 1.00?
 
tony873004 said:
Am I correct to assume that whatever filter gives the highest value will be considered to be 1.00?

That's what it looks like, though I've never seen the term explicitly defined. I think that table is just telling you how reflective the object is in the different bands (relatively speaking).
 

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