2001 Mars Observation Reports -- #09--

OAA MARS SECTION

Mars Observations
in the Second Half of May 2001
from 16 May 2001 (162Ls) to 31 May 2001 (170Ls)
based on the article published in CMO #245 (10 June 2001)


by Masatsugu MINAMI, Director of the OAA Mars Section



O

N 16 May (162Ls), the angular diameter read 16.8 arcsecs, but on 31 May (170Ls) it increased to 19.1 arcsecs. We enjoyed rather good weather at the mainland of Japan, while Okinawa has been in the height of the rainy season. The central latitude went down from 1.4S to 0.0S on 28 May (169Ls), but went back to 0.5S on 31 May. The central latitude will go up to 7.4N in mid-July. The phase angle went down from 22 to 12.

 

We acknowledge receipt of the observations as follows:

 

AKUTSU, Tomio (Ak) Karasuyama, Tochigi, Japan

4 Sets of CCD Images (29 May 2001)

f/70, 32cm spec equipped with a Teleris 2

 

BIVER, Nicolas (NBv) Versailles, France

1 Colour Drawing (28 May 2001)

330,510x 26cm speculum

CAVE, Thomas R (TCv) Long Beach, CA, USA

2 Drawings (20, 29 May 2001)

280, 430, 380, 550x 33cm speculum

 

FALSARELLA, Nelson (NFl) Sao Jose do Rio Preto - SP, Brasil

12 Drawings (7, 8, 11, 15, 19, 20, 22, 26, 29, 30, 31 May 2001)

325x 20cm speculum

8 CCD Images (22, 30 May 2001)

20cm speculum + AVA ASTROVID 400

 

GRAFTON, Edward A (EGf) Houston, TX, USA

2 Sets of CCD Images (19, 29 May 2001)

f/60, 35cm Celestron SC with an ST6

 

HIGA, Yasunobu (Hg) Naha, Okinawa, Japan

22 Video Images (16, 21, 23, 24, 25 May 2001)

25cm f/6.7 spec with Sony VX-1000

 

ISHADOH, Hiroshi (Id) Naha, Okinawa, Japan

11 Drawings (16, 23, 24, 25 May 2001)

220, 340, 400, 530x 31cm speculum

 

KUMAMORI, Teruaki (Km) Sakai, Osaka, Japan

22 CCD Colour Image (16~19, 25, 27, 28, 31 May 2001)

20cm f/12 Dall Kirkham

equipped with a Mintoron MTV-6368N or Sony PC-5

 

MINAMI, Masatsugu (Mn) Fukui, Japan

42 Drawings (16, 17, 19, 20, 25 May 2001)

400, 480x 20cm refractor*

 

MORITA, Yukio (Mo) Hatsuka-ichi, Hiroshima, Japan

43 Sets of CCD Images (16~20, 24, 25, 27, 28 May 2001)

f/50, 25cm spec equipped with an ST-5C

MURAKAMI, Masami (Mk) Fujisawa, Kanagawa, Japan

13 Drawings (17, 19, 25, 31 May 2001)

400, 320, 425x 20cm speculum

 

NAKAJIMA, Takashi (Nj) Fukui, Japan

6 Drawings (19, 25 May 2001)

400x 20cm refractor*

 

NARITA, Hiroshi (Nr) Kawasaki, Kanagawa, Japan

11 Drawings (18, 20, 21, 25, 28, 29 May 2001)

400x 20cm refractor

 

NIKOLAI, Andr (ANk) Weil der Stadt, Deutschland

1 Set of CCD Images (24 May 2001)

10cm Zeiss refractor

 

PARKER, Donald C (DPk) Miami, FL, USA

10 Sets of CCD Images (17, 18, 20, 30 May 2001)

f/44, 41cm Meade SCT equipped with a Lynxx PC

 

PEACH, Damian A (DPc) King's Lynn, Norfolk, UK

1 Set of Drawings (22 May 2001)

405x 31cm Meade SCT

 

TAN, Wei-Leong (WTn) Singapore

2 Sets of CCD Images (19, 20 May 2001)

f/16, 28cm SC equipped with an ST-7E

 

TEICHERT, Grard (GTc) Hattstatt, France

4 Drawings (20, 21, 22, 24 May 2001)

330, 310x 28cm Schmidt-Cassegrain

 

TSUNEMACHI, Hitomi (Ts) Yokohama, Kanagawa, Japan

10 Drawings (19, 25 May 2001)

360x 12.5cm Fluorite refractor

 

* Fukui City observatory

W

e hitherto regarded any period as important this season when Hellas faced to us in relation with the behaviour of the south polar hood (sph), and this was the last opportunity to observe Hellas together with the sph because the sph was at the last stage. Despite the rainy season, HIGA (Hg) at Okinawa did not miss the chance, and MORITA (Mo) at Hiroshima produced a lot of important images on 9 days. The following is a rough tentative sketch of the observations supplemented by other observations during this serious period, and a further detailed analysis shall be given if we have any more time (maybe if season-offed).

 

  1   Observations of the SPR on 25 May (167Ls):

  As was suggested the south polar cap (spc) has already been at maximum. At 167Ls a lot of observations were made in Japan where the brightness of the spc broke off seen from around longitude=250W.

  On 25 May (167Ls) we (Nj & Mn) at Fukui started from LCM=189W: The south polar region (spr) was bright, but already at LCM=199W, the brighter part was partial, and it moved to the evening side, and at LCM=248W, the spr was quite less bright in general. At LCM=267W, the spr looked duller and only light at Ausonia and its south.
  This one-sided brightness of the
spr is shown on the series of Mo's IR images at LCM=201W, 214W, 224W, and 239W in addition to the R images LCM=250W, 260W. Ausonia may be pinned down at longitude=250W.
  On the same day
Hg also obtained a series of images at LCM=204W, 213W, 223W, 233W, 242W, 252W, 262W, 272W, and 281W. At LCM=233W, the afternoon side of the spr is bright, but the morning side is dull, and at LCM=272W the bright part looks to set down.
  KUMAMORI (
Km) also on the day produced still images from a Videotape at LCM=218W, 243W, 258W: At LCM=243W the one-sided brighter part is visible, while at LCM=258W it looks to move out.
  ISHADOH (
Id) saw this polarization on 25 May at LCM=252W onward. TSUNEMACHI (Ts) pointed out that the west morning side of the spr was blurred and dull at LCM=228W.

  As to what kind of matters occupied on the afternoon and the morning side, Mo's B images will bring some hints in a final conclusion: The evening side is brighter also in B and so it is still covered by a complicated canopy while the morning side is not. It is interesting to know the ingredient of the morning side: We refrain from any conclusion at present, but it is possible for a fallout of dust to have occurred on the following side (see below).
  Dating back to 24 May (167Ls),
Mo secured images at LCM=221W, 232W, 243W, 253W: The first two give configurations similar to those on 25 May, while the one at LCM=243W looks different from the one at LCM=239W on the following day. Hg's image at LCM=233W on 25 May differs from the one at LCM=232W on 24 May, while it is similar to the one at LCM=231W on 23 May (166Ls). On 23 May Hg produced 9 images from LCM=212W to 291W every 40 minutes. Similarly at LCM=231W, the western half becomes weaker, and at LCM=270W, the preceding brighter part moves away. Thus it is expected that we may be given a hint concerning the dull part from the preceding observations from 17 to 20 May.

 

  2   Observations around Hellas:

  Hellas this time was observed from 16 May (162Ls): Roughly, Hellas was free from frost and furthermore the area to the north of Hellas appeared faded, and so the boundary of Hellas was obscured as in 1969 (this however seemed to be slightly different in 1986 where it was more whitish and clearly round). Ts noted on 19 May (164Ls) that Hellas was dull and not whitish.
  Now we are now in a position to compare the situation just above mentioned (in
1) with the spr to the south of Hellas. We have no other image than the one at LCM=260W out of Mo's images on 25 May that is comparable with the Mo images on 20 May (164Ls): Minutely the G and B images look different though roughly similar in R: The one-side evening area looks brighter on 25 May with other minor differences.
 
Mn already observed on 19 May (164Ls) that the evening side of the spr was brighter at LCM=248W and 258W, and it was the same on 20 May (164Ls) at LCM=249W and 259W: Mn regarded this as a part of the spc. On 19 May Mn also checked that after LCM=268W, another brighter part appeared from the morning limb. This corresponded directly to the spc/sph to the south of Hellas, the configuration being complicated however.
  At the following angles LCM=277W, 287W, 297W, we saw an off-white but not glittering protrusion northward from the
spr that separated also the spr bright part into two. Mo secured images on 18 May (163Ls) at LCM=283W, 292W, 302W, 311W, 324W, 329W, and on 19 May (164Ls) at LCM=283W, 293W, 303W, 313W, 324W, 333W, and those at LCM=283W and so on describe the off-white protrusion. So we can see the protrusion was already a deposit.

  Before 24 May, Mo has no image at the same angle, while on 17 May (163Ls) at LCM=291W, 301W, it is shown up. This phenomenon is interesting, and we may consider that a dust disturbance had occurred near the perimeter of the spc, and it already fell out on some portion of the spc to make it duller as well as on the southern part of Hellas to show a lighter trace of the protrusion. We will come back again to this problem later in a 2001 Note.

 

  We add that W.-L. TAN (WTn) in Singapore produced excellent images on 19 May (164Ls) at LCM=311W, and on 20 May (164Ls) at LCM=308W where the protrusion was shot. This is also clearly shown on Km's images on 17 May (163Ls) at LCM=182W, 289W, and on 18 May (163Ls)at LCM=238W, 301W. ISHADOH (Id) speculated on 23 May (166Ls) at LCM=292W that there might have been an influence of a dust cloud. We also note that Okinawa is the far west, so that Hg last observed the surface at the very angle LCM=281W on 25 May (167Ls) to be compared (Id further watched at LCM=292W on the day).

 

  3   Miscellany from Japan:

  As to the sph/spc at other regions, the part to the south of Argyre was thick and brighter at the beginning of this period as shown on 16 May (162Ls) by Km at LCM=324W, by Mo at LCM=337W, 341W, and by Id at LCM=010W, 020W. On 17 May (163Ls), Mn checked it at LCM=348W. At the end of the period on 28 May (169Ls) at LCM=193W, and on 31 May (171Ls) at LCM=174W, Km showed that the spc/sph looked brighter in general (Mo's B image shows well the brightness on 28 May at LCM=171W). Elysium looked light in the morning for example on Mo's R and G images on 28 May (169Ls) at LCM=171W, but we should note it is not shown on B, and so the morning Elysium is ground lit. On the afternoon of 20 May (164Ls) Mn however saw a slight small white spot inside Elysium at LCM=239W. On 24 May (167Ls) at LCM=223W and 233W, Id resolved it to consist of two small white spots.

  A bit about the dark markings: MURAKAMI (Mk) separated Yaonis Fr from M Serpentis on 17 May (App Diam=17.0"), and Id caught M Cimmerium completely on 24 May (App Diam=18.2"). Mo's images on 25 May and a good image by AKUTSU (Ak) on 29 May (169Ls) at LCM=206W show similarly M Cimmerium reminiscent of the aspect in 1986. Ak's series of images on 29 May (169Ls, phase angle=13) are excellent and interesting: Tharsis was thickly evident at the evening terminator at around LCM=127W, while Olympus Mons is now weak near the terminator as shown on the image at LCM=193W.

  4   Overseas Observations:

  Already on 17 May (163Ls) DPk produced excellent images at LCM=164W and at 194W where the orographic clouds at Tharsis and Olympus Mons are caught. Since DPk's B is quite exposed and so Olympus Mons is checked, but should be said quite weaker than before.

The DPk images on 18 May(163Ls, phase angle=21) at LCM=191W also show a weak Olympus Mons near the terminator. The images on 20 May (164Ls) at LCM=167W are just very enhanced to show both Tharsis and Olympus Mons. The Tharsis cloud will remain until much later, but the summit cloud of Olympus Mon will soon cease to be active.

 

  EGf's excellent images on 19 May (164Ls) at LCM=168W show a difference of the sph in B from the spc in IR light. The latter L channel image shows a zigzagged perimeter of the spc and frost-free but light Electris-Eridania. This spc corresponds to the brighter afternoon part of the spc we watched on the day. EGf's image also proves that M Sirenum remains of the same shape as in 1986. The L image seems also to show the inside detail beneath the Tharsis cloud.
  The images on 29 May (169Ls) at LCM=055W are also superb in the sense that it shows possible details of the fine structure. The
sph is thick (in B) to the south of Argyre, and it is shown that Argyre is almost now frost free. The snow line of the spc looks around at 52~55S.

 

Tom CAVE's Juvent Fons on 29 May at 9:35 GMT (above right)

     


NEWSFLASH:

 

As announced promptly by emails, Don PARKER (DPk), Tom DOBBINS (TDb) and others were successful in detecting the Sun-glint flashes from Edom several times on 7 and 8 June at the Florida Keys (see also LtE and CMO-Web; It was reported that on 7 June, the pulsations occurred from 6:40 GMT ( LCM=330W) to 7:20 GMT ( LCM=342W), and twice on 8 June from 7:00 GMT ( LCM=326W) to 7:20 GMT ( LCM=331W), and from 7:53 GMT ( LCM=339W) to 8:24 GMT ( LCM=347W)). Even if predicted, it is usually very difficult to continue the intensive watching of any small area, and so the campaign and the work at the Florida Keys are truly worthy of praise.


 

  In Japan, now the rainy days prevails. Usually (in average year), the rainy season starts from 6 June and end on 20 July in the central Japan, and hence there is not much possibility of us catching the biggest planet when it will be closest to the Earth on 21 June (182Ls). On the other hand, in Okinawa it usually starts from 8 May (this year it started on 6 May) and ends on 23 June. We so expect the observers in Okinawa lead this period in Japan.

  The next issue shall review the observations during a fortnight period from 1 June (171Ls) to 15 June 2001 (179Ls). Our CMO Web-Site has a Gallery Page where some new Mars images are flashed before our reviewing. We hope every CCD image is emailed in a jpg file with a file name beginning with the observer's name to vzv03210@nifty.com as well as to cmo@mars.dti.ne.jp. Drawings are preferred to be sent in an A4 sized format with just one drawing on one sheet.

 


Reports will be acknowledged if air-mailed to M MINAMI at Mikuni
(ask the mail-address through
vzv03210@nifty.com ) .


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