May 22, 1997

John Rogers forwarded images by Isao Miyazaki and the following message:

I observed Jupiter this morning. Unfortunately seeing condition was poor. I could not detect a STrZ white spot in visual, however it was barely detectable at p.end of the Red Spot on a TriColor image which was taken at 18:18-18:19(UT).

*TriColor Image

40cm Newtonian, LynxxPC

Joe Harrington forwards the following message From Tim Dowling, who, based on his thesis model states.

Subject: Re: GRS spot merger

I'm in Croissey-Sur-Seine in Paris.

The GRS news is wonderful.

The timescale for merging of two great spots is: partial merger 6 days; total merger (centers join last) 12-18 days. It happens very fast. Pass it on.


From Pedro Sada


We observed Jupiter this morning with the McMath-Pierce 1.5m Solar Telescope (NSO/NOAO). We had good seeing (about 1") until about 13:30 UT when turbulence started to develop after sunrise. We observed the GRS rotate into view almost to the CM and could see a bright spot north-east of it which we interpreted as the White Tropical Oval commencing to circulate anticyclonically around the GRS. We calculated a position angle of about 28 degrees (+-5) northward of the E-W central latitude at about 13:00 UT. See FAXed rough sketch. The sketch shows the position of the White Tropical Oval with respect to the GRS. Other features are shown for reference, including the White Oval to the south-east.

We took video of Jupiter with our guide camera through an OG-570 nm orange filter to enhance contrast. We expect to digitize selected portions of it for later analysis. We also took high-resolution spectra of the GRS region using CELESTE (GSFC cryogenic echelle spectrograph) at 811.5 cm-1 detecting C2H6 emission. Our setup was optimized for stellar work so we are unable to rotate the slit to match sky image rotation. We plan to perform further visible and IR observations at other wavelengths.

Pedro Sada
Don Jennings

Our Atmospheres Discipline Node of the Planetary Data System has a MAC/HB scanning capability. We can scan FAXed sketches and place them at the web site.
From Pedro Sada at the McMath-Pierce 1.5 m Solar Telescope


This morning we observed Jupiter again from the McMath-Pierce 1.5m Solar Telescope (NSO/NOAO). The white spot that we reported yesterday, which we assumed to be the Tropical White Oval being deflected northward by the GRS, was still visible. However, it was not as bright and conspicuous as the previous night. The spot also appeared more elongated and the brightest section had circulated around the GRS to a position angle estimated as 45 degrees (+-6), exactly north-east of the GRS, at 9:15 UT on May 22.

Video was obtained of the GRS CM crossing for later digitizing and analysis. No IR spectra were taken due to cirrus clouds.

Pedro Sada
Don Jennings