Wikipedia:Featured picture candidates/Sirius A and B

Sirius A and B

Reason

Middle resolution, sharp, and has enormous EV for the brightest star in the night sky, and its dull little brother and/or sister.

Articles this image appears in

=

Artifact (observational), List of nearest bright stars

Creator

HST (again! ;))

• Support as nominator --—
  ♦ (talk) 20:56, 21 November 2008 (UTC)[reply
  ]
• Oppose Conveys almost zero useful information. May as well be an overexposed car headlight. The overexposure and artifacts from the imaging totally ruin it, a single image is unable to capture the difference in brightness obviously, but overexposing one to this degree doesn't help either. It would be better for size comparison purposes as a composite of two correctly exposed images. Mfield (talk) 21:02, 21 November 2008 (UTC)[reply]

  Urgh - the entire reason I added that was because I knew people would make comments like yours - if not for the over-exposing, then you couldn't see Sirius B and then the EV would be fractured. —

  ♦ (talk) 21:04, 21 November 2008 (UTC)[reply

  ]

I respectfully disagree. A composite of two correctly exposed images would better display the relative sizes without all the artifacting from the massive overexposure. And an 8-bit output method is completely incapable of displaying the difference in brightness anyway, so any attempt to to this is flawed, we cannot deduce anything remotely exact about brightnesses of the two stars from this image except to say that one is a LOT brighter than the other. A bit of text with a large number factor on it would achieve the same, and be exact, hence I do not see this as having that high enc from the point of view of "illustrating the article content particularly well" criteria. Mfield (talk) 21:19, 21 November 2008 (UTC)[reply]

There is no such thing as sizes when it comes to images of stars. They are all unresolved. Any perceived width is due to the point spread function of the optics and the atmosphere. Therefore a composite would be misleading. Your statement about an 8-bit method being "completely incapable" of conveying the difference is also incorrect. By using the PSF, you could infer the brightness of SiriusA based on the area of pixels that are of a particular within-photodetector-sensitivity value. de Bivort 22:48, 21 November 2008 (UTC)[reply]

Is it possible to deduce the relative brightnesses of these two stars from this image alone? If so, I stand corrected. As it is, I don't believe you can without additional information that the viewer does not possess, thus this image does not add a huge amount of information to a WP reader - the accompanying text would do a better job of quantifying that. That was my point. An 8 bit image cannot display the brightness difference in a way that is meaningful to the eye, it requires knowledge of the optical system, the sensor used to capture the photons, the post processing of the consequent image, all followed by some mathematics. That's not using an image to illustrate content, not without using it to illustrate the Point spread function article at any rate.. Mfield (talk) 23:03, 21 November 2008 (UTC)[reply]

• Oppose. This is one particular representation of these two stars that is, like other possible representions, fairly arbitrary. It's an essentially artifactual image, in which the quality of the artifacts produced by the image system is meant to indicate the actual differences between the stars and/or their appearance from Earth. But the visual effect is two stars of different sizes; as the discussion above points out, the actual sizes of the stars are not what is recorded by the image. On top of that, it's not an attractive image, by FP standards, and it's not really all that sharp; there's very little extra detail apparent at full resolution compared to thumbnail size. If it was more attractive and more detailed, it would be possibly appropriate for FP as an illustration of observational artifact (one of its current uses where it does have a fair amount of meaningful detail).--ragesoss (talk) 20:31, 22 November 2008 (UTC)[reply]

• Oppose: You can't tell what it is, also, plenty of stars have binary/companion stars orbiting around them, what makes this poor quality picture any special? – Jerry^teps 10:21, 24 November 2008 (UTC)[reply]

Not promoted . --John254 22:55, 26 November 2008 (UTC)[reply]