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John,

You misunderstood my post. A output of 3" or more is required to avoid vignetting. When I tested on a SCT, the baffled draw tube where the mirror rides on is simply too small and too long in some case thus creating vignetting. But when I tried on on a Ritchey-Chretien optical tube (VRC 10), it has a 3"+ output at the rear where no vignetting were present. We tested the same on a TeleVueis and results were spectacular to say the least.

Hope this clear the misunderstanding.

Regards,
Rock Mallin

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So output does mean output... Thanks for clearing that up Rock.
I used 3" focuser (output) for this same reason... the wide light cone of my f3.3 would cause vignetting with a 2" focuser.

GregW

Edited by greg (10/09/12 01:17 AM)

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John,You misunderstood my post. A output of 3" or more is required to avoid vignetting. When I tested on a SCT, the baffled draw tube where the mirror rides on is simply too small and too long in some case thus creating vignetting. But when I tried on on a Ritchey-Chretien optical tube (VRC 10), it has a 3"+ output at the rear where no vignetting were present. We tested the same on a TeleVueis and results were spectacular to say the least.
Hope this clear the misunderstanding. Regards,
Rock Mallin

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So output does mean output... Thanks for clearing that up Rock.I used 3" focuser (output) for this same reason... the wide light cone of my f3.3 would cause vignetting with a 2" focuser.GregW

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Ummm...So we need an expensive Ritchey-Chretien (VRC 10), TeleVue or equal with a 3" aperture focuser to avoid vignetting via the x0.5 FR

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Hi,

The ccd sensor used is a Sony ICX413AQS scientific grade class 0 only. Nothing else is used. Standard ICX413AQ is fine but does not have the sensitivity and low noise of the ICX413AQS. These sensors are very difficult to obtained.

Rock M.

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John,You misunderstood my post. A output of 3" or more is required to avoid vignetting. When I tested on a SCT, the baffled draw tube where the mirror rides on is simply too small and too long in some case thus creating vignetting. But when I tried on on a Ritchey-Chretien optical tube (VRC 10), it has a 3"+ output at the rear where no vignetting were present. We tested the same on a TeleVueis and results were spectacular to say the least.
Hope this clear the misunderstanding. Regards,
Rock Mallin

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So output does mean output... Thanks for clearing that up Rock.I used 3" focuser (output) for this same reason... the wide light cone of my f3.3 would cause vignetting with a 2" focuser.GregW

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Ummm...So we need an expensive Ritchey-Chretien (VRC 10), TeleVue or equal with a 3" aperture focuser to avoid vignetting via the x0.5 FR

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Hi,

That depends of you telescope choice. Make sure if you use large sensors that your scope will be compatible to it. many SCT have a small and long mirror draw tube and cause vignetting to camera when used with a focal reducer. Just makes sense here. If you go too wide (field of view) some undesirable effect may result thus choosing the right telescope for the job is necessary. Good planning good judgement is key before spending all kind of money on stuff that may not be compatible to your telescope.

Low cost telescope = money saved. But will have to spend again to get it right with many new cameras on the market today. Its all up to you and about your budget.

At least we come forward saying "you need at least 3" of rear optical output".

Rock M.

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Any more updates, reports or news about the Universe?

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Agreed - it's a month since the last report

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Any more updates, reports or news about the Universe?

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I've started using a script that combines the Universe software with Deep Sky Stacker Live. Really enhances the video like aspects of the camera. I'm very pleased with the results.

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