2001 Mars Observation Reports -- #07--

OAA MARS SECTION

Mars Observations

in the Second Half of April 2001
from 16 April 2001 (146Ls) to 30 April 2001 (154Ls)
based on the article published in CMO #243 (10 May 2001
)

 


by Masatsugu MINAMI, Director of the OAA Mars Section



T

HE CMO shall be published twice a month for a while. This is the first of the series of the fortnight reports of this 2001 season.

  At the end of April, the angular diameter of the planet Mars exceeded the largest apparent diameter in the case of the planet in 2003. The planet this season stays so low in the southern sky that the seeing does seldom improve, while several minor markings can now be caught to the extent that it has been easier to identify the location of the clouds or haze including the south polar hood (sph). We consider that the modern observation of Mars is not concerned with the details of the markings but with the chase of the meteorological phenomena based on the sequential observations of different surfaces for days, and hence the large apparent diameter is welcome. For the moment, we are encountering the very exciting period up until the moment the south polar cap (spc) pops out. Any good ccd observation or visual observation without another sequence of trials don't make much sense. Any observation should be composed under a systematic prospect.

  We have hitherto written this report to stimulate the observers standing by to set out to observe, while we are now in a position to renew the style of presentation since the disk diameter is now over 15 arcsecs and the cloud phenomena will be main until 180Ls or so.

 

On 16 Apr (146Ls), the angular diameter was 12.1", but rapidly increased upto 14.1" on 30 Apr (154Ls). The central latitude was 1S to 2S, so that the northern and the southern hemisphere are equally seen. The phase angle went down from 34 to 30, and so the polarization of the Sun beam is still large for the white morning mist.

 

The members who contributed this time are as follows:

AKUTSU, Tomio (Ak) Karasuyama, Tochigi, Japan

5 Sets of CCD Images (16, 26 April 2001)

f/70 32cm spec equipped with a Teleris 2

 

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

2 Drawings (21?, 24 April 2001)

280, 430, 380, 525x 33cm speculum

 

HERNANDEZ, Carlos E (CHr) Miami, FL, USA

1 Drawing (24 April 2001)

220x 20cm Schmidt-Cassegrain

 

HIGA, Yasunobu (Hg) Naha, Okinawa, Japan

13 Video Images (18, 19, 22 April 2001)

25cm f/6.7 spec equipped with Sony VX-1000

 

HIKI, Toshiaki (Hk) Minowa, Nagano, Japan

3 Drawings (27 April 2001) 430x 22cm speculum

 

ISHADOH, Hiroshi (Id) Naha, Okinawa, Japan

8 Drawings (17, 18, 19, 22 April 2001)

400, 530, 320x 31cm speculum

 

MELILLO, Frank J (FMl) Holtsville, NY, USA

4 Sets of CCD Images (20, 29 April 2001)

20cm SCT equipped with a Starlight Xpress

 

MINAMI, Masatsugu (Mn) Fukui, Japan

49 Drawings (16, 17, 20, 22, 25, 26, 27, 30 April 2001)

400x 20cm refractor*

 

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

12 Sets of CCD Images (19, 21, 22, 25, 30 April 2001)

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

 

MURAKAMI, Masami (Mk) Fujisawa, Kanagawa, Japan

13 Drawings (22, 26, 27, 30 April 2001)

400, 425x 20cm speculum

 

NAKAJIMA, Takashi (Nj) Fukui, Japan

7 Drawings (27, 28 April 2001) 400x 20cm refractor*

 

 

NARITA, Hiroshi (Nr) Kawasaki, Kanagawa, Japan

5 Drawings (16, 17, 20, 23, 27 April 2001)

400x 20cm refractor

 

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

6 Sets of CCD Images (24, 26 April 2001)

f/49 41cm Meade SC equipped with a Lynxx PC

 

SCHMUDE, Richard W, Jr (RSc) GA, USA

5 Drawings (1, 7, 14, 29 April 2001)

230, 310x 10cm refractor

 

TSUNEMACHI, Hitomi (Ts) Yokohama, Kanagawa, Japan

9 Drawings (22, 27 April 2001)

360x 12.5cm Fluorite refractor

 

WASIUTA, Myron E (MWs) VA, USA

13 Drawings (16, 17, 19 April 2001)

360x 32cm speculum/ 420x 16cm refractor

1 Set of CCD Images (23 April 2000)

16cm refractor equipped with a Lynxx PC

 

 

* Fukui City Observatory

  We here pick out the following:

 

  1 Observations until 22 April:


  On 6 May, the rainy season set in at the Okinawa district (11 days earlier than an average year), but even before that the weather was poor: So HIGA (Hg) and ISHADOH (Id) were forced to quit observing from 23 April. To them however the surfaces having Hellas faced. Id noted on 17 Apr (147Ls) at LCM=253W that the southern part of Hellas was whitish bright while the evening part of the sph looked dull. Hg's Video images on 18 Apr (148Ls) at LCM=236W, 246W shows a faint dark band between Hellas and the preceding sph. Hellas in the former image looks slightly off white but becomes whiter and brighter in the latter. The darkish boundary is stable because it is still seen on 19 Apr(148Ls) at LCM=234W,244W (Hg observed from 7h GMT to 20.5h GMT). Id also saw this partition on 18 Apr at LCM=251W, and 19 Apr at LCM=254W, 264W. On Mo's R image on 19 Apr (148W) at LCM=252W, Hellas is bright, and so its part is a frosty deposit. MORITA (Mo)'s images on 21, 22 Apr (150Ls) show also a brighter (maybe frosted) part in Eridania-Ausonia.

  From around 150Ls, the afternoon cloud over Elysium Mons (215W) is known to reduce its activity. The Elysium Mons cloud on Hg's images on 18, 19 Apr at LCM=234W is considerably bright; since the phase angle is 33, the LMT is still around 3:30 PM. Elysium itself was one-point lighter than the surroundings, maybe ground lit, from LCM=180W. TSUNEMACHI (Ts) also detected it on 22 Apr (150Ls) at LCM=206W.

 

  2 Movements inside the sph:


  The season being at 150Ls, the freezing fallout of the atmospheric CO2 has begun to decelerate, and the sph also might rush in the last stage. There is however observed a gay movement inside the sph. There was an apparent difference inside the sph on 25 April (151Ls) and on the following day.


Schematic description of the south polar region
extracted from MINAMI's drawings on 25 April (151Ls) ~ 27 April (152Ls)
(observed from the same angles every 40 minutes)
showing an apparent movement of the cloud matter inside the sph
(the brighter parts being encircled by dotted lines).

  On 25 Apr (151Ls), the present writer (Mn) started from LCM=132W (at 15:40 GMT), and noticed a conspicuous bright patch on the f side, and chased it until LCM=201W (at 20:10 GMT). At LCM=142W, this patch was near the CM to the south of M Sirenum that was very dark. At LCM=162W, it moved to the evening side. At LCM=171W, another bright area appeared from the f limb, and so the sph looked composed of two bright patches, and the second one was coming and looked downward to Eridania and Ausonia at LCM=181W. Difference occurred next day:

  On 26 Apr (152Ls), Mn started from LCM=123W, but even at LCM=143W, the bright patch observed the day before did not show up. At LCM=152W, the second bright patch came out, but even at LCM=162W the preceding part stayed dull and gray. MURAKAMI (Mk) who was observing at LCM=150W also noticed the brighter part on the f side. The part was still before the CM at LCM=171W while it was brighter than the preceding day.

On 27 Apr (152Ls) (Mn started from LCM=114W), the part remained dull at LCM=143W, though the southern limb was bright. At LCM=153W, a brighter part came out from the f limb. At LCM=172W, the contrast was evident through O56. HIKI (Hk) noticed this brighter part at LCM=176W on the day. It is difficult at present to tell what the bright part found on 25 April to the south of M Sirenum is, but it is quite evident that a movement of the cloud matter exists.

  Fortunately, Mo gave a series of ccd images at LCM=149W, 162W, 172W on 25 Apr (151Ls), and the one at LCM=149W clearly show the presence of the bright area to the south of M Sirenum. Mo's latter images are comparable with AKUTSU's images on 26 Apr (152Ls); it is apparent that the images on 26 April lack the brighter area on the evening side. The patch is visible in R though it is quite evident in B.

We waited then until 30 Apr (154Ls) but it was unfortunately clouded at 17:30 GMT ( LCM=113W) at Fukui. Mo however find a lull and obtained a set of images at LCM=133W: This seems to show again a bright area at Phaethontis-Electris while Mk felt a brighter part rather at the f side; Mk observed at LCM=103W, 113W, 123W, 132W, & 142W); the one at LCM=142W was made in twilight, but the bright part was large and the dark marking including M Sirenum was quite dark. Similar kinds of observations are needed up until 180W. (In the case of the planet in 2003, the apparent diameter will be only 6.5" at 150Ls and 10" at 180Ls.)

  At the same period, Don PARKER (DPk) produced several superb images from the different angles (earlier by about 100 degrees). On 24 Apr (151Ls) he shot at LCM=028W, 034W, 049W & 056W; and on 26 Apr (152Ls) at LCM=031W, & 036W: Both days the description of the sph is very impressive. The brighter parts of the sph is composed of two, and the shadowy Nereidum Fr separates the two. The location of the preceding one may correspond to the area of Argyre. The following one looks to expand down to the morning area, and quite thick on 24 April and rather weak on 26 April. This may be connected with the one observed at around LCM=140W in Japan on 25 and 26 April.
  WASIUTA (
MWs)'s Wr47(+Murnighan IR rejection) image on 24 Apr (150Ls) at LCM=043W shows a brighter segment at Argyre. DPk's images show a faint mist over Chryse, and a white cloud at Tempe.

 

  3 Evening Olympus Mons:


  The rise and fall of the summit cloud at Olympus Mons has a pattern (as delineated in CMO #134 p1251), and classically its activity attains its peak at 100Ls ~ 110Ls, and begins to cease from 140Ls and becomes very faint at 180Ls (while Tharsis may be active till 200 ~ 210Ls). So at present it should be weaker.
Mn's observations on 25 Apr (151Ls) were as follows: At LCM=142W, the large area of Olympus Mons (133W) including its skirts appeared ground lit bounded by a roundish faint shadowy band, but did not show any white tint even at LCM=152W. At LCM=162W, a roundish small area was outlined clearly and was evident through a Green filter but the brightness was weak. At LCM=172W it became white; its LMT being 4 o'clock (the phase angle is 31). It appears like a cotton ball through G, but never strong as before. As the disk diameter increases, the presence of Olympus Mons without cloud will be easily checked. The disparity of the activities of Olympus Mons and Tharsis Montes are interesting (#077 p0636).


  NOTEs:
 As to the morning Chryse and Tharsis, we should recall that the white cloud/mist appears in an off-white tint thicker than dust, especially when the phase angle is around 30 (cf CMO #161 p1639).
  We are happy to hear Tom CAVE (
TCv) has very recovered and watched Mars this season also: He tests his eyes and seeing by trying to detect Juvent Fons every apparition and this April he succeeded at LCM=089W. We hope he will welcome as well the 2003 apparition in good health.


  For a while, the CMO shall be published twice a month. The next issue shall review the observations made during a fortnight period from 1 May (154Ls) to 15 May 2001 (162Ls). Our CMO Internet 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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