Cassini Mission

[Neil Morrison]

 On trimming my ever rampant southern boundary Hedge yesterday in the hope  of glimpsing Saturn  for a  few fleeting  moments it bought to mind  the events of the evening of the 3rd of July 1989   attempting to time the occultation of  28 Sgr by Titan. My Log book  contains the timings made  as I jammed  myself behind my C8 hard up against my northern  boundary..

The occultation started at 22h 39m 31s and finished at 22h  44m 46s according to my records.  One of our other society members of Crawley A.S using only 7 x 50 Binoculars  made the Start at 22h 39m 32s and finish at 22h 44m 32s

With the  end of the Cassini Mission looming  it is not unreasonable to reflect  upon the  small contribution that  members of the BAA made to the  targeting of the Space Craft  in refining the position of Titan and the landing of the Huygens probe successfully.

 How much easier it would have been to  make timings of the event  today  with the advent of the  fast frame  CCD Cameras that we now have at our  disposal and the  associated electronics.  

Let us  celebrate the 28th Anniversary of the  event and  when the opportunity arises again  work in conjunction with  our professional  collogues to  further  Astronomy.

[Lars Lindhard]

I saw this occultation from my home in Denmark with a friend, and we had to move the telescope around in the garden to find at spot where we could see Saturn. The planet was very low and just over the roof of the next bulding which emitted a lot of heat and made turbulence.

We timed the occultation with my wrist watch and it began about 0h 40m and ended 0h 45m on the 4th of July Danish summer time. (GMT +2)

We did not report it to anyone, but we had a great time.

[Nick James]

Wow, is it really 28 years ago! Yes, I remember the Titan/28 Sgr occultation very well, particularly the astonishing central brightening when light from the star was refracted around the limb of Titan by its atmosphere. I didn’t have any sophisticated equipment then and the attached photo was taken with a camera mounted on the back of a small refractor.

Cassini is a mission very close to my heart. I was there for the launch and will be raising a glass when it dives into Saturn’s atmosphere on September 15.

[Richard Sargent]

I was also lucky enough to observe the Titan/28 Sgr occultation, including the remarkable central re-brightening referred to above. As Saturn was low down I didn’t think I would be able to see the event from my suburban garden with surrounding houses and trees. So I needed altitude. Did I lug my telescope up a nearby mountain? No I took it to the upstairs front bedroom! See attached picture.

I observed with a 10 inch Newtonian on a Dobsonian mount, and made an audio recording to later time the event details. I recorded the occultation start at 22h 39m 44s and the finish at 22h 44m 59s and sent the results to Andy Hollis who was collating observations for the BAA. I still have his reply letter which noted observations received from about 70 observers.

The second picture attached shows Saturn above the rooftops (brightest object near frame centre). To the right of Saturn I have highlighted 28 Sgr with a couple of lines but it is faint on the picture. After observing the event I didn’t have far to go to get to bed! Yes I’ll be following the final news of the end of Cassini. Would be nice to view Saturn at the time of Cassini’s demise but I think it happens during daylight for us.

Thanks for the reminder Neil of what was a very interesting event.

[Author]

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