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 Post subject: FOV Calculator
PostPosted: Mon May 06, 2013 5:41 pm 
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Most planetarium software comes with a method of calculating the Field Of View but nothing comes more basic than this, The Sky at night field of view calculator.

Using the drop down menu enter the details of your camera and telescope. Then from the object menu select your object that you intend to see or image and it will...well :roll: ..calculate the field of the view. At best these calculator set expectations of what you can expect to see when finding and imaging objects.

Worth keeping in your favourites I think :!:

http://www.skyatnightmagazine.com/field-view-calculator

It even has the Philips SPC900NC in the menu :shock:

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Celestron 11" Telescope
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I choose to image with an 11" SCT Celestron in this decade and do the other things, not because they are easy, but because they are hard......


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 Post subject: Re: FOV Calculator
PostPosted: Mon May 06, 2013 6:17 pm 
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Cheers Carl

I have used this before and the guys at OpticStar use it to show you what to expect for the Scope / Eyepiece combination.

Someone has added the Microsoft HD WebCam as well.

Bill


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 Post subject: Re: FOV Calculator
PostPosted: Mon May 06, 2013 9:09 pm 
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Its been around for a while, I normally go directly to http://www.12dstring.me.uk/fov.htm

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Skywatcher Explorer 200P & EQ5


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 Post subject: Re: FOV Calculator
PostPosted: Tue May 07, 2013 11:41 am 
thats great Carl.
After having a bit of a play with it - at a cursory glance, by selecting M101 as the object, it appears that i can achieve a larger output sized image using my 72mm APO coupled with my MS HD webcam as i can using my C6 & the modded 450D.
That cant be right surely? Unless its a theoretical view & in practice it would be almost impossible to achieve the results on their website...
Cheers
Andy


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 Post subject: Re: FOV Calculator
PostPosted: Wed May 08, 2013 8:32 pm 
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It is all based on theoretical but one thought I had is that the life camera is 1280 x 720 and the Canon EOS is 4572 x 2848. Similar to how resolution on a PC/Laptop screen works, when you reduce the size down the icons and text get bigger.

In this instance the image gets bigger

_________________
Celestron 11" Telescope
Eq6 Pro Mount
Eq5 Mount
EQ Mod
QHY5 Guide camera
Cannon 1000D SLR Camera

I choose to image with an 11" SCT Celestron in this decade and do the other things, not because they are easy, but because they are hard......


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 Post subject: Re: FOV Calculator
PostPosted: Thu May 09, 2013 7:17 am 
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Amartin wrote:
at a cursory glance, by selecting M101 as the object, it appears that i can achieve a larger output sized image using my 72mm APO coupled with my MS HD webcam as i can using my C6 & the modded 450D

But the LifeCam HD can't do long exposures, so it's not suitable for deep-sky objects.

However, if you compare your C6/Canon with an SPC880-LX webcam on the back of that short refractor, then the field-of-view would be a little larger with your DSLR system, and the image resolution nearly four times greater.
But in practice, I doubt that you could achieve the predicted 0.72 arc-sec per pixel resolution - it's likely to be limited by the seeing, tracking and other aberrations?
And the more compact VGA images from the webcam will be forty times faster to process than the 12 megapixel DSLR images! ;)


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 Post subject: Re: FOV Calculator
PostPosted: Thu May 09, 2013 12:38 pm 
Yeah i thought it didnt stack up.
My days of VGA webcam imaging are long gone (planetary imaging non-withstanding!) fortunately; the webcams are OK but not a patch on a Canon.
As for the processing i'd rather have the highest quality image possible to play with than a lower res & faster processing time - any modern PC/laptop/Mac will handle the larger file sizes from the Canons to process without bringing the system to its knees; but its horses for courses isnt it.
Make what youve got work to its full potential - Nobody can squeeze stuff out of so little kit like Ross can, so if you dont have a modern(ish) PC etc, use what you have to its best.


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