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Old 06-07-2012, 12:40 PM
Poita (Peter)
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8MP colour @ 21fps...what is global reset?

The new Pt Grey cameras look interesting, 8Megapixels in colour at 21fps is certainly an achievement, as is 150fps in mono @ 1280x1024, but what is rolling shutter with global reset?

I know what a rolling shutter is, but not sure about the second bit
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Old 06-07-2012, 01:14 PM
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Generally a global reset is a reset of all and any adjustable settings back to default settings like as received from the manufacturer when new.
Not sure in this case though.
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Old 06-07-2012, 01:40 PM
Poita (Peter)
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This is the specs page, click on specifications for details.
8.8MP, Sony IMX121 CMOS, 1/2.5", Color, Rolling Shutter with Global Reset.
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Old 06-07-2012, 04:24 PM
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Quote:
Originally Posted by Poita View Post
This is the specs page, click on specifications for details.
8.8MP, Sony IMX121 CMOS, 1/2.5", Color, Rolling Shutter with Global Reset.
Had a bit of a look at the specs but it's not real clear as to what it does so you may have to send them an email asking for a full desription of the function.
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Old 06-07-2012, 04:55 PM
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global reset iirc allows you to reset the entire sensor with one pulse, so you can work it in with a mechanical shutter or similar.
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Old 07-07-2012, 07:52 AM
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4096 x 2160 color pixels isn't that much handy. For Sun - mono wins (narroband H-alpha, or narrowband with Solar Continuum in white light). For Lunar infrared filters are usually used. For planets so many pixels aren't needed.

As for the IMX121 sensor. It has 1.55 micrometer pixels. This is very very small. At around f/6 it will be at theoretical max scope resolution. Other IMX sensors available in USB3 Flea 3 or QHY 132E and other cameras turn out quite poor, so this newer, but with even smaller pixels doesn't look "interesting".

It also has rolling shutter which isn't the best thing - if the image is unstable you will get artifacts.

In the CMOS branch really interesting for Solar System imaging are only e2v Ruby/Sapphire and CMOSIS CMV sensors. Micron and IMX are in the "entry level" branch.
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Old 13-07-2012, 09:10 AM
Poita (Peter)
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Why would you not want more pixels for planetary if they were available in a CCD size that meant you could use them?
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Old 13-07-2012, 09:30 AM
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The cool thing about some of these new very larger sensors with high frame rates is that you can use region of interest to boost the frame rates ever farther. You can get a reasonable number of pixels for planetary photography at extremely high frame rates or use the whole chip for solar photography at just plain high frame rates. The downside is the cost of the camera.
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Old 13-07-2012, 04:01 PM
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Quote:
Originally Posted by Poita View Post
Why would you not want more pixels for planetary if they were available in a CCD size that meant you could use them?
Most of them would just show black background and the AVI size would be much bigger.


Quote:
Originally Posted by frolinmod View Post
The cool thing about some of these new very larger sensors with high frame rates is that you can use region of interest to boost the frame rates ever farther. You can get a reasonable number of pixels for planetary photography at extremely high frame rates or use the whole chip for solar photography at just plain high frame rates. The downside is the cost of the camera.
You can do that, but in the case of this IMX sensor - it has relatively small diagonal full of very small (color) pixels.

Much better would be something with bigger pixels in a bigger diagonal like those: http://www.cmosis.com/products/stand...oducts/cmv4000 or http://www.e2v.com/news/e2v-launches...aging-sensors/
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Old 18-07-2012, 02:39 PM
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Why would you not want more pixels for planetary if they were available in a CCD size that meant you could use them?
You will never use this much real estate to do planetary imaging. The main reason why is that as you increase manification to fill the sensor the image will become increasingly dimmer and therefore require the need to increase gain and reduce exposure. You will not have a scope wide enough to even use 3/4 of the sensor.

For solar you would maybe use half.

Added to that is the well depth seems far too low to me.
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Old 18-07-2012, 03:07 PM
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That is basically what I meant by if the sensor was of a size (i.e. small enough) that you could use them.

Assuming some breakthrough that allowed smaller pixels to be far more sensitive than they are today, and better well depth, would there be any benefit it higher resolutions for planetary, or is the existing 640x480 effectively capturing the resolution our scopes are capable of capuring anyway?
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Old 18-07-2012, 05:44 PM
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Size of pixels and well depth are your main concerns here. I think Anthony is using a larger sensor now but nothing in the realms of this sensor. I think 640 x 480 is the best for the planets even with a 20" scope at present.
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