Consolidated Catalogue - Why this catalogue?

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Why this consolidated catalogue?

This catalogue, 2-D and 3-D rendering project was born out of a desire to efficiently concentrate on smaller set of non-duplicative celestial objects during after-work amateur astronomy sessions. This goal was made more difficult by the layout of existing observational planning software and catalogues. There are many pre-existing catalogues and observation planning software that allow the amateur astronomer to load multiple catalogues related to an object type - for example galaxies - and then determine what might be visible. In the amateur commercial category, I use and recommend that all beginning amateurs buy Paul Rodham/iLanga's Astroplanner. As an example, Astroplanner allows the loading of several galaxy catalogues, but there is no way to easily manipulate duplicate designations between catalogues. Patrick Chevalley's Cartes du Ciel similarly provides object cross-referencing in a string in the software's object information dialogue - but again in a non-atomic form. The result is that beginning and intermediate amateurs are presented with several overlapping catalogues that contain duplicate entries. For example, an observer who has worked through the Messier's catalogue and the north latitude visible objects in Caldwell's list has already worked through a sizeable portion of the Herschel 400. Many professional catalogues also may contain objects that are too faint to be seen by a reasonable portion of the amateur community using amateur class telescopes. This can further reduce the amateur's observing efficiency.

A narrowed catalogue of key objects and object cross-referencing information are key to efficient amateur observing.

Guides and books - like Burnham's Celestial Handbook, Harrington's TUBA and Mullaney's Celestial Harvest: 300-Plus Showpieces of the Heavens for Telescope Viewing and Contemplation - partially fill the gap. These excellent guides - all of which I recommend that beginners purchase - also contain substantial overlap. These overlaps also can reduce observing efficiency from the ideal of one narrowed list of objects likely to be visible in amateur class telescopes and astrophotographs. This solution substitutes reviewing multiple guides for reviewing multiple catalogues.

Expert astronomer recommended object lists are another source for the ideal narrowed after-work DSO list. Prominent among such lists for deep sky objects (DSOs) are Steve Gottlieb's list of 662 DSOs incorporated into the chips of many digital setting circles such as the Skywizard, Lumicon's "Sky Vector" and Celestron's "Astromaster," Appendix E to R.N. Clark's classic book Visual Astronomy of the Night Sky, the Alan Dyer's Finest NGC List, the Royal Astronomical Society of Canada Deep Sky Challenge List, Messier's list (at the Astronomical League), Caldwell's catalogue (at SEDS), and Bill Arnet's implementation of the Herschel 400 (also available at the Astronomical League).

In reviewing those lists and several guides, including those listed above, it became apparent that a consolidated Messier, Caldwell and Herschel 400 list would cover more than 90% of objects in many DSO lists. Therefore, I decided to build a personal lifetime observing list - a subset of which is this consolidated DSO catalogue.

It was felt that the amateur observing community could benefit from an internet based cross-reference catalogue, which could be sorted by major catalogue, in order to be able to decode object id numbers between catalogues.

How this catalogue was developed

Many of the databases made available by professional astronomers at the catalogue service of the Centre de Données astronomiques de Strasbourg are deprecated versions - one edition behind a researcher's most current data. But for amateur purposes, their content is sufficient.

After a first pass of distance assignments were made and for the remaining galaxies without distances, a rough computed distance assignment was made using redshifts from the HyerLeda galaxy database and simple D = v/Ho; v=cz computation.

After these efforts, a few objects in the consolidated catalogue still had unknown distances.

In order to test the scope of DSOs contained in the consolidated catalogue, the catalogue was then compared against Mullaney's Celestial Harvest, Harrington's TUBA, for a few constellations, the narrative sections of Burnham's Celestial Harvest, and a few monthly guides in Sky and Telescope magazine.

Expansion into 2d and 3d rendering

Having triaxial position data for a substantial portion of the consolidated catalogue, 2D and 3D rendering was the next logical step. Triaxial plots and Milky Way structure is also a particular area of interest of this author. A schematic of Milky Arms was built using best-fit equal angular spiral arm model of Taylor (1993). The position of Sol with respect to the spiral arm ridge structure depends on the tracer against which curve fitting is made. Arm curves and distances fit using pulsars and HII regions will not necessarily result in the same ridgeline plot as those made fitted to molecular clouds. Arm distances per Taylor 1993 were adopted. A distance to the center of the galaxy (Rho0) of 8.5 kpc was adopted after Kerr (1986).

Using a spreadsheet program, 2D orthogonal projections were prepared.

Finally, using Virtual Reality Modeling Language (2.0), a generic Milky Way baseline VRML world was constructed and renderings of the Milky Way galaxy and supergalactic space to approximately 130 million light-years (40 Mkpc) were prepared. Tri-axial distance plots for catalogue objects were prepared. In a few instances, the most distant Milky Way globular clusters were omitted in order to better scale the 3D plot. A model of major structural components within 2 kiloparsecs of the Sun is included in the Milky Way 3D renderings, based on a journal search and the lay book A Guide to the Galaxy (1994) by Henbest and Couper.

Prepared by: K. Fisher 3/2006 fisherka@csolutions.net

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