Forthcoming 2005 Mars
The Case of the 1990 Apparition
0° Introduction: The apparition of Mars this year is the next one of the so-called great apparition, and so the 2005 Mars must be similar to the case we observed in 1990 which was really the next one to the 1988 great apparition. However, there is a slight difference: The planet Mars was at opposition in 1990 on 27 November (λ=340°Ls), while this year it will be at opposition on 7 November (λ=329°Ls). This is less different than the cases of 1988 and 2003 apparitions where the oppositions were widely different since they occurred at λ=277°Ls in 1988 while at λ=250°Ls in 2003. Here in 2005, the separation deceased to 20 days, and the difference of Ls also reduced by half.
We here so, for the sake of the 2005 observations, look back on the case of the 1990 how we experienced. It is recommended for the readers to refer to the Ls values and compare them with the coming values and days in 2005.
1° General Review: The CMO treated the reports of the
observations in 1990/91 twenty times (once or twice a month) from CMO #086 (5
April 1990 issue) to #105 (25 May 1991 issue). The domestic (Japanese) observers
who contributed to the CMO was 18 in number and quite less than the total
domestic contributors, 34, in 1988, The number of observations also reduced to
2700, 20% fewer than the 1988 results. Among them however, Tohru
IWASAKI (Iw) obtained a total of 400 drawings the season, and Takashi
NAKAJIMA (Nj) produced a total of 498 drawings that was the best he had
given in those years (he was 51 of age in 1990: Nj produced further a
total number of 591 drawings later in 1999). The present writer (Mn)
obtained 888 drawings (285 at
According to the 1990/91 Report of the BAA given by Richard McKIM (RMk) (JBAA, vol 102, No 5, Oct 1992), the total number of the British Mars observers in 1990/91 was 33, and so very prevailed over us. Even then the total observers and the observations were reported to have reduced by half compared with the case of 1988.
The first observation of the present writer (Mn)
was made on 4 January at
In 1990, the ccd imagers were not crowded, and in our country (ccd none yet) the observations became active after the angular diameter exceeded 9 arcsecs in August. In August there were reported about 350 drawings and TP/colour photo sets. In mid-August, the season reached λ=280°Ls, and so the spc was the main theme. At the end of September, two Typhoons (Nos 19 & 20) hit us, but in October the weather recovered rather fine. In mid-Oct, the angular diameter δ reached 15". (As anybody remembers, the planet Saturn showed, after a cycle of thirty years after, a big white oval which was detected by ISHADOH (Id) and WAKUGAWA(Wk) in Okinawa on 1 October, and the discovery was readily communicated to MIYAZAKI (My) to take a set of TP photos in an earlier stage.)
In November (λ=326°Ls~342°Ls), 500 observations were produced by the
domestic observers. N Alcyonius, Gyndes and Propontis
I were all caught, while everybody felt it not easy to detect Iuventæ Fons compared with the
case in 1988. A detail of Nilokeras was still easy.
In December, according to Id, the weather in
2° The first Dust: Even after the so-called season of the great
dust storm (at those times we set the deadline to be around λ=200°Ls~ 250°Ls), no great dust disturbance started.
Eventually no southern great dust storm was found in 1990. The rainy season at
the Hokuriku district (including Fukui and Noto) ended on 20 July, quite
normal, but the coming summer proved to be a real hot summer, and it was
On 4 October (λ=310°Ls), Don PARKER (DPk) and Jeff BEISH (JBs) detected a dust disturbance from Chryse to Eos (IAUC #5116, see also BEISH’s LtE on 6 October: CMO #095 p0808). This dust disturbance must have been one of the dusts which originated from the northern district around the nph, as is recently the well-known topic of discussion about the MGS results. The aftermath was not clear at that time however, whether it dispersed before it faced to us or not. See a detail in RMk’s article cited below. Just note the Martian season was λ=310°Ls similar to the MGS cases.
3° Activity of the nph: At the end of October, the nph was observed
very disturbed at the area of M Acidalium. The present writer’s continual observations from 20
October to 23 October (λ=320~321°Ls) were shown in a schematic figures with
4×6 partial drawings in CMO#096 at p0816. This set of figures
was also reproduced in Mn’s article in "Sky Watcher' Handbook"
(edited by J MUIRDIN, published by Freeman,
4° Second Dust: On 2 November 1990 (λ=326°Ls) there was reported an observation of a dust near Auroræ S in Italy, T PLATT in England took clearly its ccd image on 3 November, and it was chased well in Europe. This is detailed in the aforementioned RMk’s report (whose summary was made in CMO ##112 and 124), and finally a complete narrative of RMk was given in his masterpiece: Memoirs of the BAA, vol 44 (1999) “Telescopic Martian Dust Storms; A Narrative and Catalogue” (pp112~115). If we see the diagram and the original ccd images (at the Pic du Midi) made on 6 November (λ=329°Ls), the dust was clearly seen also in the northern hemisphere, and hence it is quite possible it was also originated in the higher northern latitudes though observations were lacking.
According to the catalogue of RMk, there occurred three dust storms in 1990, and the final was also observed in Chryse during 4 December (λ=344°Ls)~16 December (λ=350°Ls). At any rate, the season from λ＝300°Ls to 350°Ls is very important.
Writing up this way has inclined the present
writer (Mn) to think that der Sturum und Drang at the end of October of the nph must have possibly
been a precursor of the Chryse-Eos dust disturbance
at the beginning of November. At that time we never dreamt such a relation, but
in view of the northern originating dusts, it is quite natural to think it is
quite possible. On the day of 2 November (λ=327°Ls) when the dust was observed in
5° Tharsis Ridges: The cloud behaviour of the Tharsis ridges as
well as Olympus Mons before the opposition is an important objective to record:
In 1990, the second peak at around λ=310°Ls of the cloud activity of Arsia Mons was
clearly caught by MIYAZAKI (My) on 13 October (λ=315°Ls) at ω=095°W, 123°W and on 18 October (λ=318°Ls) at around ω=110°W. One month later, it was quite near
opposition, but those Int, R and B shots by My were precious made on 18 November (λ=335°Ls) and 19 November. Arsia Mons now ceased to
be less active than the previous case (as well as at λ=280°Ls in 1988) and showed the activity was
minimal. Olympus Mons, without cloud, looked evident however weaker than the
case in 1988. In 2005, the region will be seen around from the end of October
at λ=315°Ls in
6° Miscellaneous: The area of Solis L appeared in 1990 to be the same as in 1988 and 1986. Such a marking as Phasis was caught easily for example on MURAKAMI (Mk)’s TP photos taken by the use of a 10cm Nikon refractor (Mk secured 20 photos in October and 25 photos in November by the same object grass).
The apparition was suited to chase the final state
of the spc, while it depended on the weather and the facing longitude of the
central meridian. At
After October 1990, (we should say after
7° Finally: we note the above description heavily
depended on a review by NAKAJIMA and MINAMI “Mars Observations in 1990/91” published in “Bulletin of the
To sum up, der Sturum und Drang at the northern hemisphere after λ＝310°Ls should be important to be watched, especially to the north of Chryse and Utopia. In these cases the ccd imagers should shoot the area every 20 minutes to grasp the delicate motions of the cloud. The B ingredient is particularly important. As to a possibility of the southern dust storm around λ＝300°Ls as in 1973, we shall review in a following article (the global dust storm in 1894 was on set possibly just before λ＝300°Ls).
In 1990, it was cloudy in