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Equipment Discussions >> Electronically Assisted Astronomy

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Dennis_S253
Pooh-Bah


Reged: 11/22/11

Loc: West Central Florida
Samsung SCB-2000 specs for CCD Calc? new
      #5639295 - 01/23/13 05:34 PM

I was trying to plug some numbers for the SCB-2000 into Ron Wodaski's CCD calculater program. I'm not sure if I'm doing this right though. For Pixel Size I put 12.4 x 17, and Array Size I put 678 x 494. When I did this it came up the chip size was 8.4mm x 8.4mm. Which I guess would be 1/3" chip like the SCB-2000 has. Am I doing this right?

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mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Samsung SCB-2000 specs for CCD Calc? new [Re: Dennis_S253]
      #5639386 - 01/23/13 06:30 PM

Dennis,

I believe the correct numbers for the 1/3" sensor used in the SDC-435/SCB2000 cameras should be ...

6.35 x 7.4
768 x 494

The 1/3" chip is about 6mm diagonally.


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Dennis_S253
Pooh-Bah


Reged: 11/22/11

Loc: West Central Florida
Re: Samsung SCB-2000 specs for CCD Calc? new [Re: mclewis1]
      #5639616 - 01/23/13 09:55 PM

Thanks Mark, I found another calc program also, so I'll try both and see what happens. It just seems wierd, I plug the numbers in and even with a .5 reducer I wouldn't even be able to get a full moon. My scope is a 6", 1000mm FL F/7. Does that sound right?

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mclewis1
Thread Killer
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Samsung SCB-2000 specs for CCD Calc? new [Re: Dennis_S253]
      #5639687 - 01/23/13 10:35 PM

Dennis,

Actually it does sound right.

With my AT80ED (which is a 560mm fl scope) I can just fit a full solar/lunar disk on the slightly larger sensor in a Mallincam (which is a 1/2" or 8mm diagonal sensor). So a 1000mm scope with a .5x reducer (500mm effective) and a 1/3" sensor probably won't fit the entire solar/lunar disk ... but it should be quite close.

A couple of things to watch when trying to figure out actual fov's ...

1) the sensors have a total number of pixels and an effective number ... for example the Sony sensors are built with 811 x 508 pixel arrays (which is what some documentation states) but are actually (or effectively) 768 x 494 arrays.
2) USB frame grabbers impose another restriction to or change the actual fov displayed on a PC. They capture and display at other resolutions compared to the effective layout of the sensor. 720 x 480 or 640 x 480 are popular resolutions. Some frame grabbers/capture software are interpolating between the two (the actual or effective resolution of the sensor and the capture or display resolution) which seems to change the actual fov a bit as well.


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Dennis_S253
Pooh-Bah


Reged: 11/22/11

Loc: West Central Florida
Re: Samsung SCB-2000 specs for CCD Calc? new [Re: mclewis1]
      #5639884 - 01/24/13 12:58 AM

Wow, cool...thx for the info. So, it seems I need to look for a scope that has a lower FL. Or a better camera than the SCB-2000. It's getting to late, I need some rest. Thx.

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nytecam
Postmaster


Reged: 08/20/05

Loc: London UK
Re: Samsung SCB-2000 specs for CCD Calc? new [Re: Dennis_S253]
      #5640061 - 01/24/13 06:14 AM

Quote:

Wow, cool...thx for the info. So, it seems I need to look for a scope that has a lower FL. Or a better camera than the SCB-2000. It's getting to late, I need some rest. Thx.


As a simple rule-of-thumb the diameter of the moon [and sun] on the imaging chip is ~1% of the effective focal length of the telescope. So to get the whole moon ~5mm diameter onto an SCB-2000 chip [noted above]with some clearance around then the scope EFL = ~500mm. Of course part of the moon will appear much more detailed with a longer focal length say 1000mm - 2000mm maybe via a Barlow lens. Good luck

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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Samsung SCB-2000 specs for CCD Calc? new [Re: Dennis_S253]
      #5640356 - 01/24/13 10:29 AM

Quote:

Wow, cool...thx for the info. So, it seems I need to look for a scope that has a lower FL. Or a better camera than the SCB-2000. It's getting to late, I need some rest. Thx.




Your options list is missing the easiest one , get a different focal reducer.
A .33 FR instead of your .5 would do the trick without having to buy a new scope or a "better camera" .
The part with the better camera is especially tricky because while you may buy better or more expensive cams, they may or may not have a larger CCD size, so you could find yourself in the same situation with the new cam if the CCD is a similar size .


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barbarosa
scholastic sledgehammer


Reged: 04/11/10

Loc: "lamorinda", CA
Re: Samsung SCB-2000 specs for CCD Calc? [Re: Dennis_S253]
      #5640584 - 01/24/13 12:37 PM

Quote:

... a scope that has a lower FL. Or a better camera than the SCB-2000.




Another optionm, is to use a f/6.3 on the scope and a .5x on the cam. I had an f/6.3 reducer for visual use, and wanted a wider FOV for last the transit and eclipse last year. Adding a .5x reducer on the c-mount adapter gave me almost .5 degree. Inserting a filter between the c-mount adapter and the .5x reducer increased the FOV just enough to capture the moon or sun with my C5 and SCB-2000.


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