LtE in CMO #260

From Thomas A DOBBINS


. . . . . . . . . Sent: Sunday, May 12, 2002 3:30 AM

From: "Tom & Karen Dobbins" <>

To: "Masatsugu MINAMI" <>

Subject: Martian Flares News


Dear Masatsugu:

Please see:


A more detailed communication will follow shortly.

Kind regards,


. . . . . . . . .Date: Sat, 18 May 2002 17:59:05 -0400

From: "Tom & Karen Dobbins" <>

Reply-To: "Tom & Karen Dobbins" <>

To: <>

Subject: Saturn anomaly


Dear Masatsugu:

Attached please find an incomplete draft of an article about a phenomenon that may prove to be almost as interesting as the flares on Mars -- the "bicolored aspect" of Saturn's A ring. You will find a puzzling remark in red ("Valeri please carry this ball") in the text that is addressed to the Russian astrophysicist Valeri Dikarev, currently working at the Max Plank Institute. He is a specialist in ring dynamics and I am hoping that he can suggest a mechanism for this strange phenomenon. Just as the observations last year of Martian flares vindicated visual observers like Saheki, the images obtained during this apparition of Saturn would seem to vindicate Walter Haas.


Have Japanese observers witnessed this phenomenon?

I welcome the comments of you and your colleagues on this material.

Kind regards,


CMO Note: We should wait for the article to be published, but DOBBINS recommends an extensive observation of the Saturnian A ring when it is wide opened to check the possible bicoloured asymmetry. DOBBINS recalls the story which began when J C BARTLETT in 1942 found Ring A to be differently coloured on different sides: One side of Ring A was of clearly bluish while the other was ruddy (S&T 1945 April). This was detected in integral light, but seven years later W HAAS similarly detected the anomaly through Wr 47.


DOBBINS cites a highly processed ccd image of Saturn by M Di SCIULLO on 20 January 2002 which clearly shows the blue-red unbalance of A ring, as well as the images by M DAVIS on 8 October and 20 December 2001 showing the anomaly. So DOBBINS urges the ccd imagers to re-examine their Saturn images hitherto secured.


DOBBINS’ original Caption: Maurizio di Sciullo’s tricolor composites of monochrome images taken on January 20, 2002 through a cyan-magenta-yellow filter set with a Starlight Xpress MX-516 CCD camera and a 10-inch Newtonian reflector working at f/75. In the image at top, the saturation of hues has been exaggerated to increase the visibility of the bicolored aspect of Ring A. In the properly adjusted image at bottom, the anomalous colors persist but are so subtle that they would probably have escaped notice by visual observers unaided by color filters.


This anomaly does not appear in B ring, implying the difference of the matters and sizes composing the rings. Professionals have long been aware of Ring A's quadrupole azimuthal brightness asymmetry and so they are now interested in DOBBINS' unearthing.




. . . . . . . . .Dear Masatsugu:

Thank you. I look forward to the reactions of Sato and Horikawa.


Meanwhile, today I examined the fine collection of Saturn images in Earl Slipher's 1964 book A Photographic Study of the Brighter Planets. To my surprise and delight, I noticed that a pair of images taken on 12 November, 1943 show a very pronounced reversal in the brightness of the eastern and western ansa* in red (top) and blue (bottom) light. The "bicolored aspect" had been captured on film by that great Mars observer only one year after Bartlett's original sighting!

(20 May 2002 email)


*ansa (pl. ansae) is from the Latin for "handles"; the extremities of the major axis of the ellipse seen by Earthbound observers.

Tom DOBBINS (Coshocton OH, USA)

 Back to the LtE Home Page

 Jump to the LtE Archives


Back to the CMO Home Page