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Topic: Surface brightness

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	Surface Brightness
		The concept of surface brightness is crucial for urban and suburban observing, and indeed, for deep-sky observing of all kinds.
		The surface brightness of an object does not decrease with distance; like the total light output, it is an inherent property of the object, not dependent on the observer.
		I have derived the peak surface brightness of these objects from his data for the brightness of the central arcminute.
	mysite.verizon.net /vze55p46/id18.html (1590 words)

	Surface brightness - Wikipedia, the free encyclopedia
		Surface brightness is a concept used in astronomy when describing extended astronomical objects such as galaxies and nebulae.
		Surface brightnesses are usually quoted in magnitudes per square arcsecond.
		Because the magnitude is logarithmic, calculating surface brightness cannot be done by simple division of magnitude by area.
	en.wikipedia.org /wiki/Surface_brightness (243 words)

	Optical Techniques (Site not responding. Last check: 2007-09-15)
		Figure 6 gives the zodiacal surface brightness at 1, 2, 3, 4, and 5 AU from the Sun (upper to lower curves, respectively) as a function of wavelength.
		The surface brightness of exozodiacal light (extended emission) with a given optical depth at a chosen angular distance from a primary star will be proportional to the stellar apparent brightness.
		Exozodiacal optical surface brightness will not be easily distinguished from background and instrumental sources of scattered light without detecting a radial "edge" or azimuthal asymmetry in the exozodiacal cloud.
	astrobiology.arc.nasa.gov /workshops/zodiac/backman/V_optical.html (548 words)

	Surface BrightnessBy Paul Markov,
		Surface brightness cannot be used alone to evaluate an object's visibility, rather it complements the more widely available magnitude data.
		Galaxies observed by amateurs have an average surface brightness of about 13.5, which means that each square arc-minute of an average galaxy is as bright as a magnitude 13.5 star.
		Its magnitude is a "bright" 9.4, however because it measures 12 x 12 arc-minutes, its surface brightness is a feeble 14.2.
	www.astrobuysell.com /paul/sb.htm (976 words)

	Saturn's Moon Titan
		Brightness variations across the surface and bright clouds near the south pole are easily seen.
		Surface features are best seen near the center of the disc, where the spacecraft is looking directly downwards; the contrast becomes progressively lower and surface features become fuzzier towards the outside, where the spacecraft is peering through haze, a circumstance that washes out surface features.
		This image was taken at a distance of 339,000 kilometers (210,600 miles) and shows brightness variations on the surface of Titan and a bright field of clouds near the south pole.
	www.solarviews.com /eng/titan.htm (3083 words)

	handprint : colormaking attributes
		Since all physical light sources must have a surface area (or angular size), luminance is a truly "viewer centric" definition of light — the photometric unit that most closely approximates the perceived brightness of a light or the lightness of a surface as viewed by a camera or human eye.
		Brightness perceptions are powerfully affected by the level of luminance adaptation and the luminance of the surrounding area.
		At night a flashlight appears "bright", and "brighter" than a candle, because the contrast is with a dark surround a dark adaptation; under a noon sun, both the candle and flashlight are invisible, because they produce a negligible luminance increase in relation to the average surface luminance and the eye's light adaptation.
	www.handprint.com /HP/WCL/color3.html (17377 words)

	Low Surface Brightness Galaxy Gallery (Site not responding. Last check: 2007-09-15)
		LSB disk galaxies have similar structure as high surface brightness galaxies; that is, the light distribution falls of exponentially.
		The central surface brightness of this galaxy is 24.28
		The high surface brightness knot in one of its spiral arms actually has the same color, luminosity and H-alpha equivalent width as the entire Large Magellanic Cloud.
	zebu.uoregon.edu /sb2.html (506 words)

	Clarkvision.com Surface Brightness of Deep-Sky Objects
		The basic concept to deriving surface brightness is to measure at least one standard star (ideally multiple stars as a function of airmass and deriving the extinction corrections needed).
		Subtracting the sky reveals the nebula and allows surface brightness to be measured to very low levels, to approximately 22 magnitudes/ sq.
		A surface brightness profile for the nebula NGC 1973-6-7 in the sword of Orion shows a blue nebula that, while faint, is not as faint as the outer loop of M42.
	clarkvision.com /astro/surface-brightness-profiles/introduction.html (681 words)

	The Apparent Brightness of Deep Sky Objects (Site not responding. Last check: 2007-09-15)
		Although its published magnitude indicates that this object is bright, it is in fact one of the more difficult deep sky objects, comparable to the Owl Nebula, requiring the best of observing conditions and perhaps a nebula filter to render it visible.
		The surface brightness of an object is therefore directly related to two factors, (1) its size, or more correctly, its area, and (2) its total available light.
		If two objects were equally bright (same visual magnitude) but one was twice as large, the larger would appear four times fainter since the same amount of light is spread over an area four times larger.
	www.starastronomy.org /Library/loso4.html (1496 words)

	Aperture versus Light Pollution
		The reason lies in the distinction between an object's integrated brightness -- the sum of all the light that comes from it -- and its surface brightness, or brightness per unit surface area.
		The galaxy M33 is one of the brightest of all the Messier objects as measured by integrated brightness; however, that light is spread out over an area considerably larger than the full Moon, making it one of the faintest of all the Messier objects as measured by surface brightness.
		Small aperture places a lower limit on the integrated brightness of the targets that can be observed, while skyglow places a lower limit on the surface brightness.
	mysite.verizon.net /vze55p46/id1.html (758 words)

	3 Surface photometry and profile extraction (Site not responding. Last check: 2007-09-15)
		The main results of the present study are the surface brightness (SB) profiles as well as a set of isophotal and integral parameters, derived from these profiles.
		Surface gbrightness (SB), (B-R) colour index, minor-to-major axis ratio (b/a) and major axisposition angle (PA, 0 on positive x-axis increasing to positive y-axis) is shown versus the equivalent radius.
		The colour index profile was calculated by means of combining the B and Rsurface brightness profiles, which were obtained with one particular set of fitting ellipses applied both to the B and R frames.
	aanda.u-strasbg.fr:2002 /articles/aas/full/2000/06/ds1814/node3.html (808 words)

	Clarkvision.com Surface Brightness of M45 (Site not responding. Last check: 2007-09-15)
		The Surface Brightness distribution of an object determines its contrast and visibility as well as the exposure times needed by a camera to record it on film or an electronic sensor.
		You can see from the spot measurements that the nebula has peak brightnesses of magnitude 20 / square arc-second in the blue and is fainter in the red.
		Surface brightness magnitudes on this page are estimated to be +/- 0.2 magnitude when brighter than magnitude 20.
	www.clarkvision.com /astro/surface-brightness-profiles/m45 (290 words)

	Predicting Moonlight Brightness for Night Landscape Photography
		The brightness of moonlight illumination is quantified and a method presented for calculating exposure times required for use of moonlight as a photographic light source.
		Under conditions favorable for maximum brightness, assuming a=0 degrees, k=0.11, z=0 degrees, and with the earth at perihelion and moon at perigee, and neglecting the presence of eclipse and retro-reflective backscatter, a peak value of I=0.0426 foot-candles is calculated.
		where B is the focal plane image brightness, E is the subject surface brightness (candles per square foot), r is the lens focal ratio (focal length divided by aperture), and D is the in-line density of the optical path.
	members.trainorders.com /cimascrambler/web_page/Moonlight_Brightness5a.htm (3675 words)

	DLP - Wikipedia, the free encyclopedia
		In a projector with a single DMD chip, colors are produced by placing a color wheel between the lamp and the DMD where it is reflected out through the optics.
		The color wheel is usually divided into four sectors: the primary colors : red, green, and blue, and an additional clear section to boost brightness.
		The most similar competing system to DLP is known as LCoS ( Liquid Crystal on Silicon), which creates images using a stationary mirror mounted on the surface of a chip, and uses a liquid crystal matrix to control how much light is reflected.
	en.wikipedia.org /wiki/DLP (817 words)

	No Title
		More precisely, the irradiance of the sensor surface is proportional to the radiance of the object surface in the direction of the lens.
		The irradiance of the object surface is the amount of light falling on the surface from a given direction.
		The brightness (amount of light reflected off of the surface) is proportional to the angle between the surface normal and the light source, scaled by:
	www.cs.rpi.edu /~stewart/comp_vision/brightness/class13 (828 words)

	8.5 Mapping (Site not responding. Last check: 2007-09-15)
		Note that in the remainder of this section a clear distinction should be made between detector pixel and image pixel, the former being one of the 9 (for C100) or 4 (for C200) elements in the detector array and the latter being a `picture element' of an image.
		Assessment of PHT22 or PHT32 maps have shown that there are systematic flat-field patterns of the C100 and the C200 arrays due to inconsistent surface brightness calibration of the individual detector pixels.
		The surface brightness values and the corresponding uncertainties are summed thereby using the exposure times as weights.
	www.iso.vilspa.esa.es /manuals/HANDBOOK/pht_hb/node68.html (1240 words)

	Low Surface Brightness Galaxies
		In recent years a considerable body of data has been collected concerning these Low Surface Brightness galaxies (LSBs), and it was realized that they are crucial for studies of galaxy formation and evolution, of cosmic chemical evolution, and of the high redshift universe (especially because of their relatively large number).
		Some properties of disc Low Surface Brightness (LSB) galaxies, (scale-length and central surface brightness of the disc as a function of its absolute magnitude, in the B band).
		Since the central surface density of a disc scales as the inverse of the square of the “spin parameter” (a measure of the specific angular momentum of its dark halo), LSB galaxies can be regarded as the extension of classical spirals towards larger angular momentum systems.
	www.obspm.fr /actual/nouvelle/may03/lsb.en.shtml (1164 words)

	Astron. Astrophys. 326, 1268-1276 (1997) (Site not responding. Last check: 2007-09-15)
		The radial surface brightness profile of the coma can provide basic information about the variation of the grain column density along the line of sight through the coma as a function of projected distance from the nucleus.
		6 presents the surface brightness gradient profile for 46P/Wirtanen computed from a composite image of nine 600 sec exposures from 1996 August 17, and the corresponding gradient plot for the two 1996 November images is shown in Fig.
		There is the additional constraint observed by Lamy (1996) that the brightness of the comet varied between R = 21.6 - 21.9 over a 1.5 hour time-span, which corresponds to roughly half the time needed to exhibit the maximum range under optimum conditions.
	aa.springer.de /papers/7326003/2301268/sc3.htm (2013 words)

	Aperture versus Light Pollution
		The reason lies in the distinction between an object's integrated brightness -- the sum of all the light that comes from it -- and its surface brightness, or brightness per unit surface area.
		The galaxy M33 is one of the brightest of all the Messier objects as measured by integrated brightness; however, that light is spread out over an area considerably larger than the full Moon, making it one of the faintest of all the Messier objects as measured by surface brightness.
		If the skyglow is bright enough to swamp the Milky Way, making it invisible to the naked eye, then it will also swamp the outer disks of most galaxies as seen through a telescope, and you will be reduced to viewing the nearly featureless cores.
	home1.gte.net /vze55p46/id1.html (758 words)

	Hydrology and Remote Sensing Laboratory : Surface Brightness Temperature Map, 90 m resolution
		Surface brightness temperature maps for the USDA-ARS Walnut Gulch watershed as part of the Monsoon 1990 experiment degraded to a spatial resolution of 90 m.
		The data are from the thermal channel (#8) of the NS001 sensor from an altitude of 2400 m on day 213 (Aug. 1, 199), day 216 (Aug. 4, 1990), and day 221 (Aug. 9, 1990).* Note the clouds on day 213.
		Monitoring of Land Surface Fluxes Using ASTER Observations, IEEE Transactions of Geoscience and Remote Sensing, vol.
	www.ars.usda.gov /Research/docs.htm?docid=8482 (95 words)

	2MASS All-Sky Data Release Explanatory Supplement: Data Processing
		The "total" aperture is derived from extrapolation of the radial surface brightness from the standard isophote, out to some scale length which covers the deduced extent of the galaxy, discussed below.
		Large apertures are used to capture the lower surface brightness galaxy flux.
		A well-behaved radial surface brightness profile provides a means for recovering the flux lost in the background noise.
	www.ipac.caltech.edu /2mass/releases/allsky/doc/sec4_5e.html (1259 words)

	Ge 151a: Fundamentals of Planetary Surfaces - Tutorials
		Several things affect the brightness received by each pixel in the CCD array or each element in a vidicon image (believe it or not for some bodies this is still the best we have).
		The flux falling on the surface is the primary factor and is the same for all pixels unless the image covers such a large fraction of the planet that the solar incidence angle varies considerably from one part of the image to another.
		Defined as the ratio of the brightness of a body at g=0 to to the brightness of a perfect Lambert disk (not sphere) of the same size and distance as the body illuminated and observed perpendicularly i.e.
	www.gps.caltech.edu /classes/ge151/tutorials/tut_1.2003-05-08.shtml (1842 words)

	Low surface brightness galaxies (Site not responding. Last check: 2007-09-15)
		However, it emerges that the low surface brightness dwarf galaxy is the most ubiquitous type of galaxy in the universe.
		It is also clear that only 10% of the extragalactic contribution to the optical surface brightness of the night sky can be explained by standard galaxies.
		So, the low surface brightness is not caused by a lack of material to form stars.
	www.astro.soton.ac.uk /~crk/PH227/node41.html (325 words)

	[No title] (Site not responding. Last check: 2007-09-15)
		In this paper, the core brightness profiles are presented, while the overall morphology and the isophotal shapes are discussed in two companion papers [Jaffe et al.
		The characteristics of Type II galaxies are explained by the presence of disks component on both the 1 arcsec and the 10 arcsec scales, while Type I galaxies correspond to the classical disk-free ellipticals.
		Surface brightness values are given in units of F555W magnitude/arcsec^2 along the major and minor axes of the galaxy.
	www.journals.uchicago.edu /AAS/cdrom/volume4/volume3/aj/v108/p1598/table.doc (313 words)

	Neural Representation of the Luminance and Brightness of a Uniform Surface in the Macaque Primary Visual Cortex -- ...
		Neural Representation of the Luminance and Brightness of a Uniform Surface in the Macaque Primary Visual Cortex.
		in response to increases in surface luminance (e.g., the neuron
		Kinoshita M, and Komatsu H. The representation of the surface luminance and brightness in the macaque striate cortex (V1).
	jn.physiology.org /cgi/content/full/86/5/2559 (7005 words)

	Surface Brightness Fitting and Determination of . (Site not responding. Last check: 2007-09-15)
		This was carried out by fitting a King profile to the surface brightness taking into account blurring by the PSPC psf.
		The free parameters were the right-ascension and declination of the cluster centre, the core radius, and the normalisation.
		Examples of the fitted surface brightness profiles are shown in figure 3.2.
	www.aao.gov.au /local/www/sce/thesis/thesis/node32.html (129 words)

	UBVRI SKY SURFACE BRIGHTNESS (Site not responding. Last check: 2007-09-15)
		The RMS is estimated using the left wing of the distribution only and it is used to get the error on the final sky surface brightness.
		The contribution of the zodiacal light to the sky brightness increases with decreasing elongation from the Sun.
		Paranal sky surface brightness measured in UBVRI passbands is consistent with the values reported by Walker (1987) for CTIO during the new Moon.
	www.eso.org /observing/dfo/quality/FORS/qc/skybrightness/skybrightness_fors.html (878 words)

	A K-band central disk surface-brightness correlation with scale-length for early-type disk galaxies, and the ... (Site not responding. Last check: 2007-09-15)
		In general, galaxy types Scd or later are observed to deviate from this relation; they have fainter surface brightnesses for a given scale-length.
		Certain selection criteria biases which have troubled previous surface brightness inclination tests (for example, whether the galaxies are selected from a magnitude- or diameter-limited sample) do not operate in the μ
		Measured central disk surface brightnesses are found to be significantly (>5σ) brighter for the high-inclination disk galaxies than for the low-inclination disk galaxies.
	www.astro.ufl.edu /~graham/Preprints/incl_1.html (312 words)

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