.97H . 8. THE ASTRONOMICAL JOURNAL. 1888AJ No. 181. VOL. VIII. BOSTON, 1888 SEPTEMBER 14. NO. 13* PHYSICAL OBSERVATIONS OF MARS DURING THE OPPOSITION OF 1888, AT THE LICE OBSERVATORY, By EDWARD S. HOLDEN. The opposition of 'Mars took place April 11, 1888. The cellent ephemerides of Mars which have regularly appeared Lick Observatory was transferred to the University 6f Cali- from his hand, and which have done so much to stimulate fornia on June 1. Previous to this time Mr. Keeler was and to systematize such observations as these. the only member of the astronomical staff at the Observatory, The drawings themselves are simple diagrams, as accurate and he utilized all opportunities for observation in making a as they could be made by eye estimations alone. Circum- series of measures of the satellites of Mars, which have stances did not permit of more exact determinations of the already been printed in the Astronomical Journal. positions of the various markings of the disc. No attempt It was not until July 16, however, that the work of the at pictorial representation is made. machinists and others on the dome and elevating floor was Plate II gives seven drawings of Mars made by me with sufficiently advanced to allow of regular observations. the 26-inch equatorial at Washington in 1875, 1877 and On every suitable night since that time at least one draw- 1879. The first five of these were redrawn by Monsieur ing of Mars has been made, either by myself, Mr. Schae- F. Terby, and printed in Mémoires Couronnés de VAcademie berle, or Mr. Keeler. A list of all the drawings made Royale de Belgique, tome XXXI (1880) ; but they are com- follows : paratively unknown in America, although they are interest- ing as confirming some of the discoveries of Professor E. S. H. J. M. S. J. E. K. Schiaparelli. The other two figures are printed for the h. m h. m h m July 16 9 00P.S.T. first time. 17 9 25 44 The twenty-one drawings of Plate I (1888) form a reason- 44 July 18 8 85P.S.T. 18 8 50 44 ably complete representation of the disc when the unfavor- 19 8 25 “ 19 9 00 able circumstances of the opposition are considered. All of 20 - “ 20 - 44 44 them were made when the disc of the planet was less than 23 8 45 July 23 8 45P.S.T. ;/ 2L8 13 24 8 45 44 24 8 45 44 9 , and when the zenith distance was nearly 60° ; and all 25 7 45 u 25 7 50 44 25 8 00 44 of them were made in the early evening before the large ob- 25 8 20 “ 25 8 40 44 u 44 44 jective was cooled to the temperature of the surrounding air. 26 8 10 26 9 10 26 8 40 Magnifying powers of 350 to 700 diameters have been em- 26 8 21 44 27 8 00 44 27 8 15 44 ployed according to the various conditions of vision. 29 7 28 44 29 7 52 44 29 8 20 44 The inner satellite (Phobos) was seen on July 18, when 31 7 24 “ 44 44 it was only .22 of its brilliancy at mean opposition, and Aug. 1 7 22 Aug. 1 7 52 only ¿ as bright as at the time of discovery by Professor 2 7 23 44 2 8 00 44 5 7 28 44 5 8 20 44 Hall. 5 7 40 44 It is very unfortunate that the great telescope was not 8 7 33 44 8 7 35 44 available for these observations until three months after 44 44 9 7 38 9 8 03 opposition, and that it will be necessary to wait until 1890 9 8 30 44 10 7 30 44 10 8 00 44 to form a map of the planet based upon our owm work. Still it appears to me that the drawings here given, present Plate I gives a series of these drawings arranged in the important evidence relating to the canals of M. Schiaparelli, order of longitude of the central meridian of each drawing. and to the submergence of the 4 4 continent ” Libya reported I desire to express my obligation to Mr. Marth for the ex- and confirmed by M. Perrotin in May last. © American Astronomical Society Provided by the NASA Astrophysics Data System 97H Plate I. 8 88AJ »» ;íVm £¿±- JL^nuAyjy.gtjtrnh. £^ff. ^*o, /mJLj^M, 7 V* /#rl V» * e.iM 3**+jtr v*t^ fi+mr. Sri *t~ ^ L¿¿¿~1. fÁ+~*J ¿, JL ¿tur ¿5* » ¡ w^j "b ^tn¿f , 3* *« îi. ÍmJ«^ c-.^ji-A+iLu^, > — i ^i«4.A . a-4 •/ MULS^ j>*i'/uT-. ^ ■ v<k^ S ; V>«j Lyjíh. I 4ä;«Ä,^^. 74¿í-PxA £¿j?. 'M~lmx~rníjtn-ti*. c.j.H. ■Mza ,iai , •¿trPs t f Í.M. \*xjr à* Mj, * °+tj'. 1~Ws, ^.+xr. XtH’j'.jf. ■ y« +*/*. —«'»-SV',v tía J-«*»« K*^ A/W> « i 7*Äw 4. f w“^'í'‘rj ^ = í«r , .^. -‘ ; i*ÍA -, . 4; i ff/f44* V*Uj LjiJ. ¿: !ut ( T r 5. e; Y“*—¿ ;*u¿. ->: W Uj LrL à*. _ j 'kll- !"*■ 0*1»u,turf* , fwpxi. cm. r^r-nr. **x \ L. je*:/*, *¿jtr. JLX. JLrtXjJjUymr JTJX. m * ‘VT-^y+tv x -si*’ r \. jxr* - T7»*' I .j0j * •i ÄI {¿uútjuS ^?v ^r4*' .■ —rr^J ítuc ■ * s- *. 04* i** i r^- M~ct^ J fi,4 c~ L. ¡Mr. l r*~ í ; M« u¿L*3, u ih 4^.4 h*Üy ot >at . !• ~WP l. i Plate. II. : 1*77 etlU^cj x*t iokio'. SrSX •fe /áT? í./lVW^ \ ‘jo’t y. Z?-* Jiwu2^ \^3ír J*nx7>/j ÜJS* jfit d-o^~k 4p.d Lth, e.z~3-t~aJl X« L 9 c 0° ^/ <} so~'W¿UÍ^lt^. Jlsf.ii.fc~ ir».« í, ®f Wftdi 2¿oümc4s. Bl/m'ivrim.tf tvJu. ¿X< ;?£, £ Awafi fe cfew, . "Xe. - iAT«iwn_ ly ír- « fe r.Tefl,^ ¿fer 7 .fe-/-’.; wfe^ fer — 4 © American Astronomical Society • Provided by the NASA Astrophysics Data System 98 THE ASTRONOMICAL JOURNAL. N°- 181. 97H . With regard to the canals it appears that we have not seen PARELLi in 1877 and 1878, pot to speak of later drawings. 8. any of them double, although many of the more important It is much to be regretted that the series of drawings at have been sketched as broad bands covering the spaces on the Lick Observatory begins at so late a date ; but so far as M. Schiaparelli's map which are occupied by pairs of the evidence of our work goes, it may be said that during canals and by the space separating the members of each this opposition we have seen no double canal, and do not pair. find any important changes in the 44 continent" Libya. At 1888AJ With regard to the “ continent" Libya the observations the same time no one is more sensible than myself of the here show nothing before July 16. After that date we have highly unfavorable conditions under which our work on Mars eight drawings (July 31, July 29, July 27, July 27, July 27, has been done. We have, however, seen enough of the July 26, July 25, July 25, July 26), which exhibit this working of the great telescope on Mars and on other objects marking in various aspects, all of which are in substantial to know that its powers are amply adequate under favorable agreement with each other, and each of which differs ma- conditions ; and we confidently expect the next two oppositions terially from the observations made at Nice during April, to furnish the most conclusive evidence on these highly inter- and May, as given in L'Astronomie for June 1888, page 214. esting questions. No more could have been done here during M. Perrotin says that Libya, which was plainly visible this year than was done, but the opportunities of even a two years ago, u does not exist to-day" (April and May, single favorable opposition, diligently improved, will suffice 1888). to perfect our knowledge of the topography of Mars to a The eight drawings above mentioned show it, however, in most important degree, and two such should present us with essentially the form in which it was drawn by M. Schia- a map of the planet, which may fairly be called complete. Mount Hamilton, 1888 August 17. OBSERVATIONS ON MARS, By A. HALL. [Communicated by the Superintendent of the Naval Observatory.] Observations op the Satellites. Date W.M.T. Ap W.M.T. As Bemarks Deimos. h m h 1888 Mar. 30 12 16.1 122.91 0-53 12 27.1 50.51 —0.10 Faint Apr. 4 12 41.4 118.11 1.02 12 52.4 50.21 + 0.21 Haze, very faint 6 11 19.1 304.13 0.26 11 28.4 52.81 —0.24 8 10 4.3 130.71 0.54 10 12.3 51.26 + 0.18 11 10 42.2 296.03 0.27 13 10 10.7 125.97 0.40 10 18.2 52.78 + 0.52 16 11 13.1 292.27 0.43 11 22.6 49.67 —1.15 Very faint 20 9 0.5 306.51 0.26 9 7.5 53.73 —0.89 Faint 25 9 19.4 303.31 0.55 9 27.9 52.81 + 0.02 Extremely faint May 2 8 53.2 127.65 0.11 9 1.3 51.55 —1.10 Faint 5 9 39,7 292.61 + 0.02 9 48.7 48.69 —0.84 Extremely faint Phobos.