In the scalar Helmholtz equation the variables are separated in 11 physically interesting coordinate systems [ 55 ], however for the vector field containing 3 scalar functions, the complete separation of variables is possible only in 6 systems: Cartesian, 3 cylindrical, conical and spherical ones ([ 55 ], Ch.13). Therefore, the formal solution suggested in 1927 by F. Moeglich [ 368 ] for the spheroidal coordinates was practically usefulness until the work of Sh. ...

... Exposure Time Calculator (ETC) . ... ESO - Public Surveys . ... the recommended values to use for DIT, . ... Detector on-chip integration (DIT): seconds. to your chosen value - a separate page gives recommended values to use for DIT - for modes 1 and 2 below you may wish to start with the maximum recommended values as these will minimize the effect of read noise (a total object exposure of Y secs with DIT=X secs will produce Y/X lots of read noise) and give you a lower limit on the time needed. ...

. Distance Conversion Calculator . by Matt Oltersdorf 2000 04 02 2225 UTC . Type the known value into the appropriate units field, click the . calculate button and the program will show all values for . related unit properties. Kilometers . Meters . mm . Inches . Feet . Yards . Miles . Astronomical Units (A.U.) . Light Year (LY) . Parsec (pc) . Kilometers . Miles .

... At the simplest level of modelization, these phenomena are described by reaction-diffusion equations. The theory of this type of equation is far away from being fully understood but one can give however several results providing in some cases existence of solutions and their qualitative behaviour. ... Reaction-diffusion equations. ... Theory of uniformly elliptic equations: existence, regularity, Schauder theory, Agmon-Douglis-Nirenberg theory, Harnack estimates, boundary Harnack principle. ...

... My mother had a 'star named for me' with the International Star Registry (henceforth ISR) as a gift for this Christmas. ... On the back of the chart, a sticker described the precise location and visual magnitude of the star, taken from the Hubble Guide Star Catalog. The first thing I noticed, was the chart was Epoch 1950. ... The coordinates were also exactly those on the ISR sticker, so I now knew that even though the ISR chart was epoch 1950, the coordinates on the sticker were epoch 1983. ...

Pulkovo Photographic Plate Database . To find a certain plate, type its number, choose instrument and click button FIND Instrument: Normal Astrograph 26-inch refractor Plate number: . To find plates with a certain sky area: choose instrument, type coordinates (R.A. and Dec.) of the center of this area, type radius of this area, type (optionally) names of required objects, and click button FIND . ...

... 237S (SIMBAD/NED BibCode) ================================================================================ Keywords: Sun: UV radiation - atmospheric effects - Sun: atmosphere - lines: identification Description: An ultraviolet atlas of the solar spectrum with a spectral resolution of 15mA in the region 1948-2000A is presented. ... The wavelength atlas with a list of about 550 lines has been synthesized from data at center of the Sun ({mu}=1) and at {mu}=0.89, smoothed out over an area of 30 arcsec. ...

Johann Kepler - a Legislator of the Sky. The laws of the planets movements put by Johann Kepler destroyed the thousand year old dogmas about the circles and spheres and opened the way to scientific understanding of celestial occurrences. ... The best object for observation was Mars - its orbit unlike the Earth's one has a noticeable eccentricity, the rotation period in comparison with Jupiter and Saturn is not too long and observation conditions are better than for Mercury and Venus. ...

... Regional planning meeting for the Balkan and Black Sea | ... Proposals for a web site of the Regional Network - Information on regional and global activities - Proceedings of this Meeting - Space Weather Alerts for the public - Form for submitting research and observational proposals - Database of scientific data publicly available - Greece provides solar telescope data - Romania provides data on active regions studied with helioseismis holography - Armenia provides access to...