LtE in CMO #279

From Thomas A DOBBINS

. . . . . . . .Date: Tue, 09 Sept 2003 15:51:25 -0400

Subject: Mars image


Dear Masatsugu and Masami:


Attached please find an image of Mars taken at 4:25 U.T. on September 7, 2003. CM=308 degrees. This is my first attempt to use the ToUcam that has produced excellent results in the hands of so many observers, notably Eric Ng and Tan Wei-Leong.


The image is a composite of the best 900 frames from a sequence of 1800 (selected, aligned, and stacked automatically using Registax software) obtained in good seeing (7+/10 ALPO-Pickering scale) using my C-14 at f/28 with a Barlow lens. A 2-degree wedge prism was interposed between the Barlow lens and the webcam in order to correct atmospheric dispersion, which was very pronounced at the planet's rather low elevation of 34 degrees.


Simple wavelet processing performed in Registax was employed to produce an image intended to mimic the planet's visual appearance through the same telescope rather than to extract the maximum possible amount of detail. I think that this will be my customary approach in the future, as I am quite pleased with the result.


Kind regards,


. . . . . . . .Date: Thu, 18 Sept 2003 00:58:45 -0400

Subject: Corrected Mars images 16 September


Attached please find Mars images for 16 September at 03:50 UT


355mm SCT (C-14) at f/28 with Phillips ToUcam. Seeing 8/10; Transparency 5/6.


First image with Minus-IR filter shows extensive haze and cloud on morning limb; second image taken without Minus-IR filter to emphasize surface features.


Kind regards,


. . . . . . . .Date: Sun, 21 Sept 2003 10:46:03 -0400

Subject: Mars Image 21 September 3:38 UT CM=169


C-14 at f/28 with 2-degree wedge prism and IR blocking filter. Seeing = 5~6/10. Transparency 5/6.

Discrete orographic cloud over Arsia Mons. Extensive hazes over Phaethontis on evening limb and Elysium on morning limb.


. . . . . . . .Date: Sun, 21 Sept 2003 14:11:50 -0400



Dear Mr. Murakami:


I have noticed my image already promptly posted on the CMO web site. The images displayed are slightly darker than the jpg-files appear on my monitor for some curious reason. I have adjusted the image sent very recently in an attempt to compensate for this effect. If you wish, you may replace the previous version with the one attached. Sorry to trouble you. In future I will take the effect into consideration in advance and not trouble you in this way again.


Kind regards,


Tom DOBBINS (Howard, OH, USA)

 Back to the LtE Home Page

 Jump to the LtE Archives


Back to the CMO Home Page