Re: [ap-gto] Re: [ap-ug] Saturn Last night


Jan 21, 2004

 


----------------------------

#20633 Jan 21, 2004

In a message dated 1/20/2004 9:10:47 PM Central Standard Time,

sreilly@... writes:



> I joined the ap-ug just to see these pictures. Wow!!!! How 'bout some

> details on exposures etc.?

>



The exposures for the 3 channels are Red and Green @ 0.2 seconds, Blue at 0.3

seconds. All 150 images were combined after stretching in Maxim DL to produce

the three color channels (50 for each color). The images were then screened

for sharpness and the best ones from each color were culled out, and combined

for the L channel (about 80 images). The final LRGB (with the L channel being

synthesized) was produced at 16 bit in Maxim DL with subsequent sharpenign

filter and mediam filter used to enhance the contrast. No unsharp masking was

used. The image was adjusted for best detail for Saturn. I then went back and "dug

out" the fainter Moons and used Photoshop to layer them in. If I had done it

in one shot, the main planet image would be grossly overexposed. 4 of the

Moons were readily visible in the eyepiece, but then the eye has much higher

dynamic range. There are 5 Moons visible in the image. A 6th Moon is suspected and

I may go back and try to dig it out using some more advanced stretching. Does

anyone know of a program that predicts the positions of the Moons on the night

of Jan 19th?



I see that the Jpeg images I posted on the user group files shows some ragged

edges on the bottom of the rings. These seem to be compression artifacts that

are not present in the Tiff images. I may go back and see if I can get a

better image to post later this week.



Roland Christen





[Non-text portions of this message have been removed]



----------------------------

#20637 Jan 21, 2004

Roland:



There is a JavaScript utility at the S&T site

(skyandtelescope.com/observing/objects/planets/article_1136_2.asp#)

that shows the positions of Titan, Rhea, Dione, Tethys, and Enceladus for

any date and time from December 2003 through July 2004.



Karl Perkins



-----Original Message-----

From: chris1011@... [mailto:chris1011@...]

Sent: Wednesday, January 21, 2004 10:27 AM

To: ap-gto@yahoogroups.com

Cc: ap-ug@yahoogroups.com

Subject: Re: [ap-gto] Re: [ap-ug] Saturn Last night





In a message dated 1/20/2004 9:10:47 PM Central Standard Time,

sreilly@... writes:



> I joined the ap-ug just to see these pictures. Wow!!!! How 'bout some

> details on exposures etc.?

>



The exposures for the 3 channels are Red and Green @ 0.2 seconds, Blue at

0.3

seconds. All 150 images were combined after stretching in Maxim DL to

produce

the three color channels (50 for each color). The images were then screened

for sharpness and the best ones from each color were culled out, and

combined

for the L channel (about 80 images). The final LRGB (with the L channel

being

synthesized) was produced at 16 bit in Maxim DL with subsequent sharpenign

filter and mediam filter used to enhance the contrast. No unsharp masking

was

used. The image was adjusted for best detail for Saturn. I then went back

and "dug

out" the fainter Moons and used Photoshop to layer them in. If I had done it



in one shot, the main planet image would be grossly overexposed. 4 of the

Moons were readily visible in the eyepiece, but then the eye has much higher



dynamic range. There are 5 Moons visible in the image. A 6th Moon is

suspected and

I may go back and try to dig it out using some more advanced stretching.

Does

anyone know of a program that predicts the positions of the Moons on the

night

of Jan 19th?



I see that the Jpeg images I posted on the user group files shows some

ragged

edges on the bottom of the rings. These seem to be compression artifacts

that

are not present in the Tiff images. I may go back and see if I can get a

better image to post later this week.



Roland Christen





[Non-text portions of this message have been removed]







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----------------------------

#20651 Jan 21, 2004

In a message dated 1/21/2004 1:09:20 PM Central Standard Time,

karl@... writes:



> There is a JavaScript utility at the S&T site

> (skyandtelescope.com/observing/objects/planets/article_1136_2.asp#)

> that shows the positions of Titan, Rhea, Dione, Tethys, and Enceladus for

> any date and time from December 2003 through July 2004



Thank you. Stephen Russell also pointed it out to me.



Roland Christen





[Non-text portions of this message have been removed]







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