Milky Way Galaxy Schematic

Consolidated DSO Catalogues - R.N. Clark's Appendix E, Herschel 400, Messier and Caldwell with Cross-referencing to NGC, Catalogue of Principal Galaxies (PGC), Arp's Peculiar Galaxies, Barnard's Dark Clouds, and Lynds's Dark Clouds (N=823) with a 3D Rendering of the Milky Way Galaxy and Virgo Supercluster

K. Fisher Rev. 1/19/2008

Go to: Catalogue Bibliography 3D World (Self-loading Cortona VRML) 3d World Help and Content Make voluntary donation
Go to: 3D Constellations 150pc 3D Milky Way Galaxy Arms 8kpc 3D Milky Way Globulars and Warp 60kpc 3D Milky Way System 150kpc 3D Local Galaxy Group (3.26Mlyr) 3D 10Mpc Coma Cluster (32.6Mlyr) 3D 40Mpc Virgo Supercluster at z=0.01 (130Mlyr) Great Sky Surveys to z=0.2 (2.4Glyr) Quaser Surveys to z<3.0 (11.47Glyr) Hubble Deep Fields to z=5.5 (12.6Glyr) Gamma Ray Bursts to z=6.3 (12.86Glyr) Cosmic Microwave Radiation Background at z=17.5 (13.4Glyr)
Go to: Tracers of Orion Arm structure 3D Solar System Orientation in Milky Way

Shapley's 1919 Globular Cluster Diagram
Figure 1 - Shapley's 1919 2D Globular Cluster Diagram
from Shapley's Twelfth paper
Globular Clusters 3D
Figure 2 - Globular clusters in 3D - 32kpc view

3D Rendering - Globular Clusters (Self-loading Cortona VRML)
Virgo and UMa Clusters in 2D to 40Mpc as seen during the spring
Figure 3 - Virgo and UMa Clusters in 2D
Virgo and UMa Clusters in 3D
Figure 4 - Virgo and UMa clusters in 3D - 40Mpc view

3d Rendering - Virgo and UMa Superclusters to 40Mpc (self-loading Cortona VRML)

May 2007- Jan. 2008: Due to enhanced security in Microsoft Internet Explorer 7.0, the 3D Cortona ActiveX plug-in will not activate all features implemented by the 3D renderings provided here. Security settings in Internet Explorer 7.0 will need to modified to fully use the Cortona Active X control. Normally, the Cortona viewer runs fine under MS IE7.0. However, the original version of this site was written under MS IE5.0 and an earlier version of Cortona Viewer. Subsequent MS IE7.0 security modifications blocked some of the earlier functions relied upon in these 3D VRML renderings, unless they are explicited allowed by the user under MS IE7.0. The ParallelGraphics Cortona viewer is a widely distributed, major commercial VRML 3D plug-in and, in this author's experience, can be implicitly trusted. trusted. Always are always use the links marked "Self-loading Cortona VRML".

Modifications to MS IE7.0 Internet Security Settings to allow the Cortona Viewer to fully implement the 3D renderings: Under MS IE7.0, under Tools | Internet Options | Settings | Security | Internet | Custom Level, set:

The major VRML 3D rendering feature implemented is these modifications is object identification rollover. When the cursor rolls over a object shown in the 3D renderings, its NGC catalogue or other id name, its galatic latitude and longitude, and its distance in kiloparsecs, is shown on the status bar.

If you are previewing this site for the first time to view 3D content, use the links to the 3D renderings marked "self-loading Cortona VRML." If you are viewing this website from a public access point, such as a public library or school, that blocks ActiveX plug-ins for Microsoft Internet Explorer, you will be unable to view all 3D content on this site. The 3D renderings on this site require user approval of use of the Cortona virtual reality modeling language (VRML) plug-in. There is subtantial non-3D content on this site. Read more about obtaining and installing the freeware ParallelGraphics Cortona VRML Player...

Alternatively, you can right-click here, to download a local copy mirror of this site and then run the VRML worlds from your local harddrive. Direct VRML links are included on the assumption that future versions of MS-Internet Explorer and Cortona will resolve the incompability.

Cross-reference Tables for Consolidated Catalogues - R.N. Clark, Herschel400, Messier and Caldwell Catalogues sorted by:

A V magnitude of "99" means that no reliable magnitude catalogue entry could be found, or, in the case of dark clouds, that an emissive magnitude is not applicable.

The catalogue can be exported to a Microsoft Excel spreadsheet by opening the top table labeled "J2000 coordinates." Copy the internet url of the table from your browser's address bar. Use the File Open dialogue in MS-Excel and paste the url into the file name box. Excel will open and convert the internet table into a form that you can sort and filter within Excel.

Consolidated Catalogues - Cartes du Ciel external catalogues

Spending as much time as possible at the eyepiece makes for a good amateur astronomer. It is in this spirit that the above cross-reference catalogues were generated, i.e. - to reduce object look-up times. It is in this spirit, the following supplemental planetarium catalogue files for the freeware Cartes du Ciel planetarium software are offered. The author's intention is that the planetarium program catalogue will provide a comprehensive but narrowed list of deep sky objects accessible by the amateur, such that on any one night, a reasonable set of celestial objects of each type will always be visible. The 3D renderings provided below are intended to supplement but not supplant enjoyment of the night sky.

Right-click and "Save Target as" -

The user can locate objects of the same type or in the same structural association (e.g. the Perseus Arm) using the lookup lists, locate the object in their telescope assisted by the Cartes du Ciel planetarium software or other package, and then supplement that enjoyment with the 2D and provided below. The structural assignments and 2D and 3D renderings provide sufficient information to prepare observing tours by location, e.g. - "Open Clusters of the Perseus Arm."

Introduction - Why this consolidated catalogue? How it was developed. Read more ...:

Astronomical distances

Inherent uncertainty

Distances to celestial objects outside the solar system are inherently uncertain. Perhaps other than a stars within 100 parsecs of the Sun whose triaxial position was determined by the European Space Agency Hipparcos satellite, most astronomical positions are known with certainty to a tolerance between 5%-30% of their actual positions. The level of certainty depends on the method used to fix their position. While astronomical journals and catalogues were searched in order to assign a supportable distance to the objects in the consolidated catalogue, the reader should view such distances as general low-precision estimates. Read more about astronomical distances at Ned Wright's Cosmology Tutorial . . . (external content).

Distance-then vs. Distance-now

The vast distances at which astronomical objects are found is intimately linked with time by the limitation of the speed of light.

As examples, take Betelgeuse (alpha Orion) at an approximate distance of 465 light-years; Sirius (alpha Canis Major) at an approximately distance of 8.5 light-years, and NGC884, an open cluster that is part of the Perseus Double Cluster, at a distance of 7,600 light-years. When we see these stars and cluster at night, their light is reaching us from different time frames.

When we look up at night, we see stars whose light tells us of events are arriving from millions of different time frames. Think of it in terms of an analogy to lightning bolts on the Earth. When sitting inside during a lightning storm, one sees the flash of the bolt against window curtains and then a few seconds later hears thunder arriving. The further the lightning bolt, the longer it takes for the sound of the lightning to reach us. Even when sitting indoors, it is possible to build a mental map of the distance to the lightning bolts just from amount of time it takes for the sound of the bolt to reach us. The same holds true for the stars, except that the "lightning bolt" from the star can take years, thousands-of-years or even millions-of-years to reach us.

This experience is counter-intutitive to our daily life. We are used to seeing light arrive in a few billionths of a second from nearby objects - like a car across the street or the person sitting next to you. Everything in daily life is in the same time frame.

When the positions of astronomical objects are expressed based on the light currently arriving from different timeframes of when the light left those objects, such positions and object distances are expressed as distance-then. This is common form of astronomical position and distance seen in star categories.

For many nearby objects within the Milky Way, like Betelgeuse, Sirius, or NGC884, their position and distance can also be expressed as distance-now. Distance-now is the projected position and distance of an object in our present time frame on Earth. Take open cluster NGC884. In general, we know what direction it is traveling in the night sky and how fast is moves per year. By projecting where it will be in 7,600 years, its position can also be expressed as "distance-now" or where it is at the current time.

Many objects in the night sky, like very distant galaxies, have a known distance-now but there is no way to determine their present triaxial positions. We know their distance-then positions, based on the sometimes billions of years that it has taken for their light to reach us. We may also know generally whether they are moving towards or away from us. But such objects move so slowly that we do not know in which specific direction, in terms of the points on the compass, that these far galaxies are moving. Because of this lack of knowledge, modern astronomy cannot define a triaxial position in the "distance-now" timeframe for many galaxies.

Because the distance-now three dimensional positions for many far galaxies is unknown, the distances stated in the 2D figures and 3D renderings that follow are always distance-then positions - its position when the light left the source object - as normally occurs in all charts and catalogues used by astronomy hobbyists.

But readers should be aware that they are seeing only a snapshot of the universe as it appeared particular times in the past. Everything in the night sky has moved since the light that we now see has reached us.

The Powers of Ten metaphor for astronomical scale

The Powers of Ten analogy, first pioneered in the 1950s by Kees Boeke and in the 1960s by Office of Charles & Ray Eames, provides a coherent framework for presenting the relative size of the universe. Gott (2005). In the Powers of Ten analogy, the universe is presented in units of one-centimeter times the number 10 raised to the nth power. The solar system is in the range of 10 to the 15th power, the Milky Way Galaxy is in the range of 10 to the 21th power; and the Virgo supercluster in the range of 10 to the 24th power. The baseline unit to present the following 2D and 3D renderings is 1,000 parsecs, or the kiloparsec. One parsec is the physical distance represented by a star that subtends 1 arcsecond of angular distance when photographed by two observers separated by 1 astronomical unit - or the distance between the Earth and Sun. This angular distance, or parallax, is usually measured by taking two photographs of a star separated by six months in time. One parsec is equal to approximately 3.26 light-years; one kiloparsec 3,260 parsecs. Where appropriate, in addition to the kiloparsec radius of 2D or 3D rendering, the corresponding size of a 2D or 3D rendering in the Powers of Ten analogy is also stated.

About the 2D and 3D Renderings of Consolidated Clark-Herschel400-Messier-Caldwell Catalogue

Understanding what the plane of the Milky Way Galaxy looks like at various times of the year

A beginning point for understanding the Milky Way Galaxy is to understand what parts of the galaxy are seen throughout the year as the Earth completes one orbit of Sol. This understanding requires gaining an appreciation of the tilt of the Earth's orbit (the plane of the ecliptic of the Solar System) with respect to the galactic plane at the equinoxes and the solstices. The tilt of the ecliptic plane with respect to the galactic plane is extreme - about 62 1/2 degrees.

A result of the high inclination of the Earth's orbital plane to the galactic plane is the Earth's view varies widely throughout the year. At the vernal or spring equinox, the Earth is at its highest northern point relative to the galatic plane. The Milky Way's galactic plane is nearly coincident with the observer's horizon. Figure 9. An observer at 40 degrees North latitude looks "up" and "out" the top of the Milky Way's plane through the relatively star-free region of the Coma Bernices. Three months later at the summer solstice, the Earth has moved counterclockwise one-quarter of its orbit and the observer at 40 degrees North latitude looks "sideways" towards the Milky Way's galactic core and the rich star and gas regions of the Sagittarius Arm and the constellation Sagittarius, e.g. - the Lagoon Nebula, Messier 8. At midnight on the summer solstice, the plane of the Milky Way appears to run north and south relative to the observer's horizon. Figure 10. At the autumnal equinox, the 40 North latitude observer now looks "down" and "out" the Milky Way's plane towards the south galactic pole. Figure 11. At midnight on the winter solstice, the observer is again looking "sideways," through rich star fields and gas nebula in the galactic plane to the next galactic arm out - the Perseus Arm. The Orion Nebula, M42, is located in this direction, as is the "unwinding" anti-spinward direction of our local Orion Arm. Figure 12.

The following are 360 degree altitude-azimuth charts of the night sky at 12 midnight and 9pm at the equinoxes and the solstices, generated using Cartes du Ciel:

Milky Way at Vernal/Spring Equinox at 12AM from 40 deg N
Figure 9 - Milky Way at Vernal/Spring Equinox at 12am from 40 deg N lat
Milky Way at Summer Solstice at 12AM from 40 deg N
Figure 10 - Milky Way at Summer Solstice at 12am from 40 deg N lat
Milky Way at Autumnal Equinox at 12AM from 40 deg N
Figure 11 - Milky Way at Autumnal Equinox at 12am from 40 deg N lat
Milky Way at Winter Solstice at 12AM from 40 deg N
Figure 12 - Milky Way at Winter Solstice at 12am from 40 deg N lat
Milky Way at Vernal/Spring Equinox at 9PM from 40 deg N
Figure 13 - Milky Way at Vernal/Spring Equinox at 9pm from 40 deg N
Milky Way at Summer Solstice at 9PM from 40 deg N
Figure 14 - Milky Way at Summer Solstice at 9pm from 40 deg N lat
Milky Way at Autumnal Equinox at 9PM from 40 deg N
Figure 15 - Milky Way at Autumnal Equinox at 9pm from 40 deg N
Milky Way at Winter Solstice at 9PM from 40 deg N
Figure 16 - Milky Way at Winter Solstice at 9pm from 40 deg N lat

The orientation of the Earth in its orbit relative to the galactic plane is best understood by taking mental snapshots of the night sky at midnight at the equinoxes and the solstices. However, most amateurs are used to seeing the night sky at 9pm local time. The Earth's daily rotation also effects the apparent orientation of the Milky Way to the observer. In the foregoing figures, the night sky as seen at midnight and 9pm local time are illustrated. Comparing Figures 9-12 and 13-16, there is an evident pattern. The sky at midnight at the spring equinox (Figure 9) looks nearly identical to the sky at 9pm on the summer solstice (Figure 14). Similar pairings are seen for the other equinoxes and solstices. Figures 10 and 15, 11 and 16, 12 and 13.

Even with these 2D representations, visualizing the Earth's orbit - the ecliptic - with respect to the Milky Way's galactic plane can be difficult. The following 3D renderings provide a supplemental visual aid. In the 3D renderings (see Figure 17), the orbit of the Earth is greatly exaggerated in size. If drawn to scale, the entire solar system would be a minisule point at the intersection of the axes. The Earth is shown at the equinoxes and solstices.

Two sticks pierce each Earth. The black stick shows the orientation of the Earth's axis and runs through the Earth's North and South poles. The second red stick piercing each Earth shows the geographic location of an observer at 40 degrees North latitude in North America. The Earth is rotated to its relative position at midnight. The direction of the tilt of the Earth's axis is fixed and remains the same regardless of its orbital position as the Earth revolves around the Sun in a counterclockwise direction. This results in some visual anomalies. On the day of the vernal or spring equinox at midnight, the Earth is tilted away from the direction of the Earth's travel in its orbit. On the day of the summer solstice at midnight, the Earth is tilted perpendicular to direction of orbit but pointed towards the Sun. On the autumnal equinox at midnight, the Earth is tilted towards the direction of orbital travel; and, at the winter solstice, perpendicular to its orbital travel, but away from the Sun.

In the 3D renderings, next to each Earth globe are floating panels that show the corresponding view of the night sky at 12AM and 9PM local time. These panels are the same as Figures 9-16, above. The user can rotate the 3D renderings in order to build a better map of the relationship of the Earth's orbit to the Milky Way's plane and structure.

A bright green line that extends from the origin of the axes in the 3D renderings represents the solar apex, or the apparent direction that the Solar System is moving. The solar apex is in the constellation Hercules (J175700.07+262829.5, G052.00+23.00 per Jaschek 1992). The solar apex was discovered by finding the average proper motion of all stars in various directions. Walkey 1946. Higher proper motions, on average, of nearby stars occur near the solar apex as illustrated in Figure 18. This indicates that this is direction that the Solar System is moving.

The solar apex in the constellation Hercules appears in Figure 10, Summer Solstice at 12AM, and in Figure 15, Autumnal Equinox at 9PM, above, and in the corresponding floating panels in the 3D renderings.

Another consequence of the Earth's orbit relative to the galactic plane is that amateurs see a limited part of the Milky Way during each major season. These effects can be seen in Figures 9-16 above and the foregoing 3D renderings.

Ecliptic Plane and Galactic Plane illustrated - Snapshot of 3D rendering
Figure 17 - Ecliptic Plane and Galactic Plane illustrated - 3D VRML Snapshot

Proper motion of nearby stars during the last 10,000 years and the solar apex - from Cartes du Ciel
Figure 18 - Proper motion of nearby stars during the last 10,000 years and the solar apex - from Cartes du Ciel

In the spring at midnight, amateurs can look "up" and "out" the "top" of the Milky Way's plane and have a relatively unimpeded view of distant galaxies. Figure 9. At the summer solstice at midnight, rich star fields that are dense with gas clouds and open clusters in the galatic plane towards the galactic core (galactic longitude 0 degrees) are visible. The "spinward" portion of our local Orion-Cygnus galactic arm is visible through 90 degrees galactic longitude. Figure 10. At the autumnal equinox, the amateur can see portions of the Perseus Arm stretching east to west along the local zenith from Cygnus (90 degrees galactic longitude) to Gemini (~180 degrees galactic longitude). Figure 11. But the observer can also see "down" and "out" the Milky Way's plane towards the south galactic pole - into a relatively star free region and towards distant galaxies in the constellation Fornax. Figure 11. At the winter solstice, the amateur again sees the rich star fields full of open clusters and nebula, like M42 in Orion, all contained in the Milky Way's galactic plane. Figure 12. Near the winter solstice, the northern observer sees from the galactic anti-center near Gemini towards galactic longitude 270 degrees in the constellation Vela. This portion of the sky, near Canis Major, also contains the "unwinding" or "antispinward" portion of our local Orion Cygnus Arm.

Close readers of the Earth and Ecliptic Plane 3D renderings may notice a facial contradiction. The ends of the right ascension axes are labelled with name of the corresponding event, e.g. - autumnal equinox, winter solstice, etc. The corresponding Earth globe and night sky panels are labelled with the right ascension event 180 degrees opposite to each Earth globe. For example, the axis labelled "RA 12 hr . . . Autumnal Equinox" is next to the Earth globe and panels marked "Vernal/Spring Equinox." This is not an error. When the Earth is at the vernal equinox, the Sun appears 180 degrees away against the background of the constellation Aries at right ascension 0 hours. The display is confusing, but accurately reflects the physical model.

3D Renderings of Nearby Stars and the Consolidated Clark-Herschel400-Messier-Caldwell Catalogue

Beyond the Limits of Amateur Telescopes and the Consolidated Catalogue - and to the Limits of the Observable Universe

The 40Mpc z=0.01 (130Mlyr; 1.234 x 10^26 cm) world of the consolidated catalogue and the Tully Nearby Galaxy Catalogue represents the practical limits of the amateur observer equipped with a consumer visual class telescope of up to 10" to 12" of aperture.

Beyond that is another world of extreme high z distances being investigated by professional astronomers. In the following renderings, the red two-polar 40 Mpc grid used in previous 40Mpc z=0.01 3D renderings is maintained at its 40Mpc size in order to give a sense of scale between the world of the amateur discussed above and the more distance realm's being investigated by the professionals.

  • Galaxies in major sky surveys past z=0.1 (40 Mpc; 130Mlyr; v=3,000kms; 1.234 x 10^26 cm ) to z=0.2 (738.6Mpc; 2.4Glyr; v=60,000kms; 2.279 x 10^27 cm)

  • A series of surveys have explored to the limit of the inherent brightness of typical galaxies as contrasted against the night sky's inherent brightness around visual magnitude 19. That distance roughly corresponds to z=0.2 or about 800 Mpc under current, generally accepted cosmological models, again for typical galaxies and Earth-based telescopes. (Other atypically bright objects, like quasars discussed below, have z values higher than 0.2, but are still visible to amateur and professional class Earth based telescopes.)

    The following links can be used to view "wedge" slices plotting the positions of galaxies that are among the major results of each survey:

    For the technically-minded, the size of the wedges were computed from the survey z value and a cosmological model of Omega-mass=0.27, Omega-energy=0.73 and H_0=0.71. The distance is the light-travel or distance-then time, converted to megaparsecs.

    At the scale of these surveys (the 2dFGRS survey contains data on over 200,000 galaxies), galaxies no longer are referred to by group membership, as seen in the 40Mpc view, but are now aggregated hierarchically in clusters of galaxy groups called superclusters. Nomenclature for these groups and superclusters change between new surveys. Fairall (1990) and Tully's 1987 Nearby Galaxy Atlas provide a nomenclature schema for nearby rich or superclusters.

    Abstract distance scalars like "z=0.2" or "203 megaparsecs" are difficult to relate to the concrete amateur experience of the 40Mpc Virgo supercluster sky. The following rendering shows the relative sizes of the Tully z=0.01 survey familiar to amateurs as compared to the first three survey wedges listed above:

    At this scale, it becomes apparent at that DSO galaxy night sky familiar to amateurs inhabits a small portion of the bottom corner of the 2001 Zwicky Slice.

    Galaxy survey wedges to z=0.2
    Figure 40 - Galaxy survey wedges to z=0.2 - 3D screen snapshot

    The best amateur rendering of this scale of supergalactic space remains Powell's Atlas of the Universe website and his view of supercluster space to 1.0 billion light-years, 306Mpc, or about z=0.075.

  • Beyond the Galaxy Sky Surveys at z=0.2 to z > 25

  • z=0.2 to z > 25 is equal to: (738.6Mpc; 2.4Glyr; v = 60000kms; 2.279 x 10^27 cm ) to (~4.1Gpc; 13.7 Glyrs; 1.265 x 10^28 cm ).

    Milky Way Structure and Supergalactic Structure - Index with Internet Casebook Reader

    Learn about history of astronomy, the structure of the Milky Way, how astronomers discovered the structure of the Milky Way, and the structure of the supergalactic universe by reading astronomical journal articles, websites and some hard copy books. Get a sense of how astronomical scientific knowledge is incrementally discovered through the scientific process. Although most of the journal articles contain higher level math that is beyond the average amateur, many journal articles contain narrative conclusions and figures that are within the range of most amateur readers. NASA ADS Services redistributes - for single download, personal reading - astronomical journal articles - many of which are subject to copyright protection. The Reader-Bibliography is an index to landmark journal articles and books and other resources with external content links to the NASA ADS and other websites. To learn more about Milky Way structure and astronomy history, start reading here . . .

    Other 3D Milky Way or Universe renderings


    Centre de Données astronomiques de Strasbourg - Simbad: This project has made use of the SIMBAD database, operated at CDS, Strasbourg, France.

    Centre de Données astronomiques de Strasbourg - Catalogue Service: This project has made use of numerous catalogues redistributed through the CDS Astronomer's Catalogue Service, operated at CDS, Strasbourg, France. Catalogues that were utilized are listed in Bibliography and the Distance Bibliography. The use of those sources are by this reference is acknowledged and appreciated.

    NASA Astrophysics Data System/Computation Facility at the Harvard-Smithsonian Center for Astrophysics - NASA ADS Abstract Services: This project has made use of NASA's Astrophysics Data System.

    Parallelgraphics - Cortona VRML player: This project has made use of the Parallelgraphics free VRML Player (v. 4.2) in the development of its 3d renderings. << >>

    Nigel Henbest and Heather Couper: This project was inspired by the N. Henbest & H. Couper's 1994 book The Guide to the Galaxy. Cambridge Univ. Press. (

    Salt Lake Astronomical Society: At the time this site author was created, the author was a member of the Salt Lake Astronomical Society (SLAS). While SLAS neither participated in nor endorses this project, the use of SLAS's 16 inch Ealing Telescope at SLAS's Harmon's Observatory in the Stansbury Park Observatory Complex (SPOC) at Tooele, Utah remains a continuing inspiration, which is acknowledged here. Provides site tracking data.

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    Download a local copy of this site.

    It is the nature of the internet that information contained on it is temporary. This website was developed for the enjoyment of the amateur astronomical community and as an introductory educational aid for high school and college students. I encourage students and other amateurs to freely download, store and/or redistribute this website.

    A local copy of this site on a laptop my also be useful for studying Milky Way structure and galaxy superstructure at the telescope's eyepiece in the field.

    If materials in this website are incorporated into other websites or papers and if you wish to acknowledge the use of this site in websites or publications, please use a phrase such as the following: "This [website or paper] has made use of materials generated by K. Fisher."

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    This site is not an alpha version of a software product intended for future commercial distribution. These lists and 2D and 3D renderings will not be distributed commercially.

    Like many hobbies, amateur astronomy relies on the goodwill and fraternal desire of its participants to freely share without charge. This author remains committed to that standard of conduct in the amateur astronomical community. But in this instance, the many nights and weekends over a five month period needed to develop the underlying spreadsheet database, to review professional astronomy journals for the reasonably current and accurate distance information, and to develop VRML rendering scripts, ethically appeared to justify an entirely voluntary donation request.

    Revision History

    Prepared by: K. Fisher 5/2006