LtE in CMO #285

From Damian A PEACH

. . . . . . .Date: Tue, 9 Dec 2003 23:47:19 -0000

Subject: Latest trip


Dear Friends,


Here is a small selection of photos during my recent visit to Tenerife. Superb views of Mercury were obtained from the mountains (the brightest i have ever seen Mercury appear to the naked eye.) The sunset that evening was observed from the excellent Mirador de Chio site at 2000m alt. The image of the Observatorio del Teide was taken from the top of Mt. Teide at 3555m altitude and several km away (at full zoom.)


All photo's have been reduced to 30% of actual size.


Best Wishes,


. . . . . . .Date: Tue, 23 Dec 2003 20:43:56 -0000

Subject: Saturn on December 16th.


Hi all,


Here is a Saturn image from December 16th. Seeing conditions were good to excellent. A small dark spot was captured. The full data set follows to the relevant people.


For this image:


00:21 UTC (CM1=318.4, CM3=331.6.)


11" (28cm) SCT @ f/31. ATK-1HS CCD (Luminance) and Philips ToUcam pro (RGB.)


L: ~3000 x 1/10th secs. (ATK)

RGB: ~1000 x 1/25th secs. (ToUcam.)


Altitude: 60degs.


Merry Christmas to all.


. . . . . . .Date: Wed, 24 Dec 2003 15:05:40 -0000

Subject: Re: Saturn on December 16th.


Hi Paolo,


>>But there's something strange: 3000 frames multiplied 0,1 secs gives 300 secs (5 minutes!!!), a too longer time for a "spinless" Saturn imaging!


Thanks for your mail. In fact, you are not correct in that 300secs is to long. CCD images produced by Ed Grafton and Myself using windows of 360secs using cooled CCD indicates this is fine for Saturn. In fact, Ed's images were the very first to discover the white spots at -40s on Saturn, and this was done with such an imaging window. Also, all the images i produced last apparition were done using 300secs window, and no notable blurring occurs, when spots were present on the globe.



>>Further, I don't believe you used all the frames captured, so the elapsed time should be still longer!



I used 3000 of 3600 images. Seeing was very good, so little change between each raw frame occurs.



>>But you also managed a CCD setup with the webcam (1-2 minutes?) and a 250 secs RGB color avi through it.



Changing between cameras takes about 10 secs, and about 10-15secs refocus for the RGB data. This doesnt affect the final LRGB image since the atmospheric details present in the image are resident in the L image, while the RGB is simply the colour information. Both cameras can be controlled from the same software, so this is very convenient.


Best Wishes,


Damian PEACH (UK)

ALPO/BAA Jupiter Sections; BAA Saturn Section


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