HERSCHEL (LS): "Herschel 400" Objects (19921130)
FILE: herschel.ls
CONTENTS: Positions for the "Herschel 400" observing list
DATASET: This file comes in the basic dataset supplied with HyperSky. version 19921130 Availability on HyperSky CD-ROM: Vol. 1 (1993)
DESCRIPTION: The "Herschel 400" are a selected subset of 2,477 deepsky objects compiled by William Herschel and later included in the larger New General Catalog by J.L.E. Dreyer. Herschel's catalog is significant because it was the very first systematic survey of the heavens using a large telescope. The survey was begun by William Herschel in the late 1700s, and finished by his son John Herschel, who took his father's telescope to South Africa to study the southern skies. The resulting catalog contained 5,097 objects, 4,630 of which were discovered by William or John Herschel. It was published as "The General Catalog of Nebulae" by John Herschel in 1864.
The "Herschel 400" observing list represents a subset of William Herschel's objects which can be seen in 6-inch or larger telescopes. The list is intended to provide a challenging observing project for amateurs with modest equipment who must also contend with modern light-pollution problems. The list is directed primarily at amateurs who already have a fair degree of deepsky experience. New amateurs should perhaps first attempt to observe the shorter Messier list of about 100 relatively bright objects.
The HyperSky position-list names objects using both the original Herschel classification scheme, and the more widely recognized NGC (New General Catalog) number. Herschel's classification scheme placed each object into one of 8 lists, each list representing a particular sub-catagory. These sub-catagories are:
Class 1 : Bright nebulae
Class 2 : Faint nebulae
Class 3 : Very faint nebulae
Class 4 : Planetary nebulae
Class 5 : Very large nebulae
Class 6 : Very compressed and rich clusters of stars
Class 7 : Compressed clusters of small and large stars
Class 8 : Coarsely scattered clusters of stars
Thus, for example, Herschel object designation H-224-2 refers to object number 224 in Herschel's class 2 list of faint nebulae.
The "Herschel 400" list was developed by members of the Ancient City Astronomy Club of St. Augustine, Florida. An available manual provides descriptions and logs for observing and recording observations of list objects, and a certificate will be awarded to amateurs observing the entire list. For more information, write to: Brenda Branchett, "Observatory House", 515 Glen Haven Dr., Deltona Florida 32738, U.S.A.
The HyperSky position-list follows the organization of the above manual by breaking the list into 4 seasonal sections for fall, winter, spring and summer. The spring list of 186 objects is the largest of the four, encompassing as it does the many galaxies in the vicinity of the Virgo galaxy cluster. The HyperSky list is generally based on the above-mentioned manual, but includes a number of position corrections found by cross-reference checks against other sources.
Remember that this is only a position-list; it does NOT actually display an object at the position you select. The object you select will appear at the position only if you have also loaded a HyperSky datafile that contains it. This is not a problem if you load all files provided with the basic HyperSky set; then only a few diffuse nebulae will not appear at their marked positions.