LtE in CMO #279

From Johan WARELL


. . . . . . . .Date: Tue, 09 Sept 2003 23:08:32 -0400

Subject: Mars September 9


Dear all,


An image of Mars from last night, unfortunately in rather poor seeing (again). A drawing will arrive as soon as it is scanned.


Cloud activity is low, with equatorial ev and mo clouds over Syrtis and Solis Lacus. NPH is very thin and blends into limb hazes at this longitude.


The frequency filtered blue image does not represent the natural extents and opacities of clouds and hazes. At a later date I will send versions of the unfiltered blue channel for all dates I have image data.


Best wishes,


. . . . . . . .Date: Tue, 16 Sept 2003 14:57:04 -0400

Subject: Mars Sept. 9, 10, 11, 12, 13, 15


Dear all,


A new batch of Mars observations from the past week. It has been interesting to follow the gradual rapid shrinking of Novissima Thyle during this period. I can no longer detect it visually in my moderate seeing skies and 25 cm aperture.


The drawings and webcam images will follow in two separate e-mails.


Best wishes,


. . . . . . . .Date: Sat, 20 Sept 2003 13:31:47 -0400

Subject: RESEND Mars Sept. 10, 11, 12, 13, 15 (webcam)


Dear Masami,


I am resending my webcam images here as it seems you did not receive them.


Best wishes,




. . . . . . . .Date: Sun, 21 Sept 2003 16:32:53 -0400

Subject: Mars Sept 17, 18


Dear friends,


Two more sets of webcam Mars images. A drawing from Sept 18 and an image from last night Sept 21 will also follow in due course.


All the best,


. . . . . . . .Date: Sun, 21 Sept 2003 20:22:25 -0400

Subject: Mars Sept 21


Hi again,


Last night's best image, from Kitt Peak at 2100m but with only slightly better seeing than downtown.


Yes Richard, you're right in that especially the blue images show spurious linear streaks. They are definitely not real. This effect is evident on some dates, some not. I do not currently know what causes this, but I have noticed it from the first night I began imaging. It is reminiscent of the fringing effect seen in red and near IR flatfields and spectra occurring with ordinary silicon chips due to interference in the chip structure. But this is mainly evident in the blue. Will look further into this as time allows.


Anyone has any ideas?


Best wishes,


Johan WARELL (Lunar and Planetary Laboratory, Tucson, Arizona, USA)

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