Johann Gottfried Koehler's Original Deepsky Catalog

Johann Gottfried Koehler's Catalog of Nebulous Objects was published by Johann Elert Bode in 1779, in the "Astronomisches Jahrbuch" for 1782.

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    Observation of the comet of the year 1779

    and discovery of some new nebulous stars, by Inspector Köhler, communicated by Mr. Bode

    .. [other stuff omitted]
    Already on December 17 of last year [1778], Mr. Inspector Köhler sent me a list of various nebulous stars recorded by him since 1772, and in his latest writing of August 1 of this year [1779] he added some newer ones. Most of the he has recorded with a 6-feet Dollond-ian tube, for this purpose magnifying 30 times, determined their situation with respect to mostly telescopic stars by visual judgement only; but these indications are sufficient to find these nebulous stars in the sky. Most of those indicated in this list already occur in my complete list of nebulous stars, which can be found in the volume of the "Ephemeriden" for 1779, 2nd part p. 69 and succeeding. Of those which I have not found, there will follow a drawing and position in the following volume [for 1783], because the plates are already taken for the present one [for 1782]. Their position is given as follows: [M59, M60] On the occasion of tracking the comet of this year [1779], on April 11 and 13, Mr. Köhler has discovered another two very small [faint] nebulae barely visible in the 3-ft Dollond telescope northwest in a triangle with Rho and the 34th star of Virgo, situated closely the one above the other, and on May 5, again three other somewhat nebulous stars in the area of the northern shoulder of Virgo, at quite a distance of each other.

    When the position of these and the previously discovered nebulous stars will be determined more acurately in longitude and latitude, I will be able to deliver a supplement in running numbers to my complete list, for which recently contributions have been promised from Italy also, via Prof. Bernoulli.
    [M92] On this occasion, I also want to announce that on December 27, 1777 I [Bode] have discovered a new nebula in Hercules, not known to me, southwest below the star s in his foot, which shows up in a mostly round figure with a pale glimmer of light. Its longitude is about 11 deg [Sgr] [251 d] and its latitude 66d north.Together with two small [faint] stars, which don't occur at Flamstead, it appears in the reversing telescope as shown in fig k (in the following volume).
    [M64] Also, on April 4 of this year [1779], when I [Bode] located the comet in the evening north above Vindemiatrix in the Virgin [Virgo], I have found a small nebulous star, about 1 deg to the northeast near the 35th star of Berenice's Hair [Coma Berenices], the longitude of which is about 1 deg [Lib] [181d] and the latitude is 26d north.

    For his observations, Mr. Köhler makes use of a 10-feet Dollond telescope; a 7 to 8 shoes [feet] Newtonian telescope from Hearne and the big Löser-ian Gregorian Telescope, of which comprehensive information and an image is in Hofrat Kästner's edition of the Optik of Mr. Smith; He gives the following remarks about it: Through the 10-shoe [feet] Dollond I have normally found near Saturn only 3, rarely 4 satellites, but responsible for this is without doubt the low altitude of Saturn over the horizon. The Dollond magnifies 150 times, if I use an eyepiece of 19 lines, and herewith has all necessary light and sharpness. The Löser telescope magnifies 300 times, has still more light than the Dollond, but a bit less sharpness, but I read small letters at a far greater distance than with the Dollond. The Newtonian big telescope doesn't reach even the Dollond, because the mirror has suffered very much from the hands of its previous owner.

    [M3] From the Astronomisches Jahrbuch for 1785:

    Observation of a nebulous patch at Bootes, by Mr. Inspector Koehler.

    From a letter of the same of Jun. 17, 1782

    Some days ago I have discovered a nebulous star not included in your catalog (*) near the 3rd and 9th star of Bootes, with that stars if makes an almost equilateral triangle. It has the following position with respect to these and neighboring stars. (**) See Fig. V., Tab. III. With my star micrometer I found on the 15th [of June, 1782] at midnight the following distances: 
    The Nebula from the 3rd of Bootes  2d 54' 20"
The same from the 9th   -   -      3  18  30
The same from a in the drawing     2  27  28
The same from c   --      --       0  29   5
c from the 3rd of Bootes           2  45  27
c from b of the drawing            0  55   0
b from the Nebula        -    -    0  55   8
a from the 9th of Bootes  -   -    1  22  40
a from the 3rd    --     -    -    3  20   0
3rd from 9th       --     -   -    2  51  32
d Bootes from the 9th     -   -    3  56  48
    After a chartlet, which I based upon the Right Ascension and Declination reduced to January 1, 1780 (from Flamsteed's catalog), of the 3rd and 9th star, it follows: 
                Mag            RA            Dec [N]

    
c.        7.           202d 37' 48"    29d 16'  0"
Nebula   rath.vivid    203   4   0     29  24  45
e         9.           203   9  30     29  23  30
b (***)  7.8.          203  31   0     28  43  32
the 3rd  6.7.          204   6  48     26  48  44
a         6.           205  53  20     29  45   0
the 9th  5.6.          206  37  41     28  34  28
d         5.           210   4  36     26   8   5
    Of this nebula, which Mr. Messier has first noted on May 3, 1764, mentioning has occurred already in the previous volume [Jahrbuch for 1784], page 182, and why this one doesn't occur in my first catalog of nebulae. Now, the previous observations of Mr. Koehler show me, that in the VII-th volume of the Paris 10-year ephemerides there occurs a typing error in the declination of the same [nebula] and instead of 26d 32' -- 29d 32' should be read. (****) Therefore, this nebula is listed just three degrees to far south in my sky charts. I will deliver the supplement promised in the previous volume to the catalog of nebulae mentioned; there have been promised contributions by Mr. Mechain for this. In my new complete catalog of fixed stars, the number of nebulous stars, star clusters and nebulae visible in our latitudes goes to One Hundred.

    (*) S. Berl. Ephemerides f. 1779 [Bode's catalog]
    (**) In the Fig. I have been able only to introduce the stars closest neighbored to the nebula, therefore, among others the star a is missing.
    (***) Is a star observed by Mr. Darquier. S. Jahrbuch for 1784, p. 192.
    (****) In the Connoissance des Tems pour l'année 1783, there is correctly 29d &c. declination.

    References

    Translated from German by H. Frommert

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    Last Modification: September 12, 2006