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first go at imaging saturn

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20 years 6 months ago #1753 by dave_lillis
first go at imaging saturn was created by dave_lillis
Hi ALL,
I had my first go at serious planetary imaghing on Tuesday night (dec30th).
I got shots of saturn and jupiter using my 12" LX200 (F10) +flipmiorror + toucam pro. Jupiter was only ~5 degrees above horizon while saturn was within 1 hr of the meridan, what a dramatic differance it made. I didn't use an equatorial wedge, just used normal altaz mode.

I also had a look at the trapezium with the webcam and it was only then I realised that my collimation was slightly out (not noticable at the eyepiece). I was just about to correct it wheh the clouds rooled in, Murphys law. Next time I'll check it out on a star before I take anyshots.

I didnt use the barlow lens, but should have in hindsight, I generated a 70 frame avi file and used registaxs 2 to allign/stack and process. I also used photoshop to process (20 mins).
I wasn't going to spend to much time given that the collimation was out.



Look at the differance the atmosphere has on jupiter, It was so bad that I had to grayscale it.



This shot of the trapezium shows the mis-collimation.

Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)

Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor

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20 years 6 months ago #1754 by michaeloconnell
Replied by michaeloconnell on topic Re: first go at imaging saturn
Hi Dave,
Nice images there. I like the one of the Trapezium. Shows it up very clearly. Interesting how the collimination became more apparent via the webcam. Must try it some night myself.

I was also wondering what sort of magnification does the webcam create. When u see the image on the screen, what sort of magnification would u need in your scope to create something similar.
I tried to quantify the variables involved and came up with the following list:
--- Apparent size of image on screen - this is dependent of size of monitor, screen resolution etc
--- Distance from eye to monitor - typically about 0.5m
--- Apparent seperation between stars in image - can be measured from software such as Starry Night or actually measured by astronomers using various techniques such as CCD cameras etc
For my monitor, I have the following settings: 19" @ 1400 x 1050.
If I get a ruler and measure the distance on the monitor betwen the brightest star in the trapezium and the star to the left of it, I get a distance of approx 5mm.
I can now calculate the angular seperation of these stars in the image as viewed from 0.5m away. I get an angular seperation of 0.573 degrees.
(Circumference of circle with 0.5m radius = 2*500*pi = 3141.59 5/3141.59 = 0.00159145. Multiply this by 360 degrees to get the result)
The real seperation between these stars is 13.3 arcsecs = 0.2217 arcmins = 0.003694 degrees. www.laughton.com/paul/rfo/trap/trap.html
This implies a magnification of 472x....... 1 / ( 0.573 x 0.003694)
For a 12" f/10 as Dave has, this would require a 6.4mm eyepiece to produce a view of the trapezium of similar size.
Does all this make sense and actually give a correct answer? If there's any incorrect assumptions or calcs, I'd be grateful if you'd indicate them as it's a while since I did all these sort of maths!!
Thanks,
Michael

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20 years 6 months ago #1758 by dave_lillis
Replied by dave_lillis on topic Re: first go at imaging saturn
Hi Michael,
That sound just about right to me, funny how the 3 pics i put in here didnt come up, you can copy/paste the addresses shown in your browser to get them on screen.

Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)

Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor

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20 years 6 months ago #1761 by jhonan
Replied by jhonan on topic Re: first go at imaging saturn
Hi Dave,

I think you need to close the [img size=320] tag by putting [/img] at the end;



like this:

(no spaces)

You should be able to go back and edit your post and put in the missing [/img] tags. Use 'preview' to make sure it looks right before submitting it.

Regards,
John.

Everyone in Ireland buys Meade, and they all buy them from Lidl.

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20 years 6 months ago #1767 by dave_lillis
Replied by dave_lillis on topic Re: first go at imaging saturn
Hi John,
Thanks for that,
the modification worked

Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)

Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor

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20 years 5 months ago #1868 by michaeloconnell
Replied by michaeloconnell on topic Re: first go at imaging saturn
Tried imaging Saturn just now. Took an avi of 1500 frames @ 5fps. Did a quick process in Registax and the result is below. No idea why there's no colour. Will check out tomorrow when I'm AWAKE what caused that...must have done something silly :?


Michael

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