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Atik 414EX a possible near live imaging camera for EAA

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#101 ccs_hello

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Posted 24 May 2015 - 05:11 PM

Technical content, feel free to ignore...

 

I'll suggest, especially for EAA deep-space dim objects use cases, ....

 

1. make sure it has a very good "Live" processing software with features beneficial for astro use

 

2. look for the detail spec on its A/D converter resolution, if possible, get its AFE's (A/D converter and other components) part number

    e.g., AD9949A is an AFE (analog front-end) that has a 12-bit A/D converter in it (this model is popular in high end analog video cam as well as low end "image head")

    e.g., the same firm's AD9824 is a 14-bit AFE typically used in a DSLR or a mid-range astro "image head"

    e.g., same firm (analog devices) ADDI7013 is an AFE that has 16-bit AD converter (of course it's for an even higher end) <-- more costlier part

 

    Please note some mfgs use these terms which are not good way to describe the real spec:

    - 8 bit output (sensor has 12-bit A/D)  <-- fuzzy uncertain spec, many CMOS image sensors can operate in 8, 10, 12 bit A/D mode, depend on setting  

    - 16-bit data format (no mentioning on A/D converter's actual spec.) <-- it is possible to fit 12-bit digital data in a 16-bit data word

 

3. If the AFE part number is known, one can always look up its capability on analog signal gain (some model can be set very, very high)

    <-- the built-in internal gain-stages (in the form of CDS gain, pre-amp gain, and VGA amp gain) are usually much cleaner than the ad-hoc bolt-on LNA

 

    Some AFE parts have very high analog signal gain capability prior to its A/D converter

 

4.  Why I mentioned (2) and (3)?  It is about the topic on how to get the CCD signal extracted in a digital form while keep the "Noise" components at bay.

     If the astroCCD image head mfgs know how to squeeze out the best possible CCD analog output signal (and contain the N part of distraction at the same time),

     select the most optimal AFE part (more A/D converter bits and higher possible gain-stages), and

     let the gain-stage GAIN setting be user configurable,

     then it can be a winning formula.

 

P.S. In many scenarios, A/D converter resolution is not the bottleneck, the CCD analog signal's own S/N (too much noise) is the problem.

        Theoratically, a 16-bit resolution can represent (6.02N + 1.76 db <-- N=16) 98.08 dB while most of CCD cannot be easily squeeze out such a high quality signal source in the first place.

 

Clear Skies!

 

ccs_hello


Edited by ccs_hello, 24 May 2015 - 05:13 PM.


#102 ccs_hello

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Posted 24 May 2015 - 05:31 PM

Summary in three sentences:

 

1. somehow get CCD to output the cleanest possible analog signal (better source S/N)  <-- multiple tricks exist in astroCCD field

2. use a quality AFE that best match the CCD's analog output  (clean analog gain stage, high quality/high resolution A/D conversion) <-- to convert and extract CCD analog signal into digital data in finest details

3. use premium software algorithms (take advantage of image science) to process CCD image sensor's raw data (now in digital form) such that astro objects' features can be extracted and pleasantly viewable by human visual

 

Find who is credible in field 1, 2, and 3.

Whenever possible, do not use "draft" mode for fast data acquisition and processing.  "Getting a new image out one second faster"  <-- is it really that important for that 1 sec difference?

 

 

Clear Skies!

 

ccs_hello


Edited by ccs_hello, 24 May 2015 - 05:32 PM.


#103 ccs_hello

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Posted 24 May 2015 - 06:45 PM

I got an inquiry about "why 14-bit or 16-bit A/D helps?  Why not just amplify signals in the first place?"

 

My answer is to  use AFE's analog gain block to amplify signal to a level sufficiently to be precision measured.

 

Use a simple example, some one gives you a short pole (*small signal) and ask you to measure its length, the ruler you have only has the centimeter scale (no finer than that.)

 

The classic way is to use the litho tool (similar to a signature dup machine or reverse of engraving tool) to scale out the pole to be 10x longer  Then measure the "magnified pole".

( <-- imagine the noise component is the error introduced during the magnification process.)

 

Alternatively, you can take advantage of the modern technology to use a micrometer ruler with 1/10mm precision to measure the original stick.

It may turn out to be the winner.

 

I am not pushing for just one method only but the combined solution.

that is, use analog gain block (internal to AFE) to magnify the signal enough, but not too much to let noise overwhelm the good signal,

then use the fine measuring capability to "fish" the faint signal out.

 

The point is the firms like Analog Devices, Burr Brown, Rockwell/Harris/RCA. many others have been in this science-oriented business forever. 

DSLR mfgs such as Nikon, Pentax, astroCCD imagers firms are all using these.

That should shine some credibility into it.

 

Hope this answers.

Clear Skies!

 

ccs_hello


Edited by ccs_hello, 24 May 2015 - 07:05 PM.


#104 Relativist

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Posted 24 May 2015 - 08:38 PM

So do you have any concrete information on either camera?

It sounds like your saying I can imply usage for EAA from the commonly used analog IC chips, and that doing more isn't worth it?

#105 ccs_hello

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Posted 24 May 2015 - 09:08 PM

Curtis,

 

All I can find is Atik 414 EX uses 16bit ADC and read noise is 5e.

I don't know from it provided software if it is possible to user-set its AFE's analog gain.  <-- Many astroCCD imager vendors choose to provide their gears at their most optimal S/N setting.  Such factory default setting will not be the high-gain setting.

 

Regarding the company ATIK itself, many know in earlier days, the origin was Artemis CCD family of products as good wells from knowledgeable professionals.

Later they sold the product family to ATIK.   They certainly are the pros and know how to get the best out of a CCD sensor.

 

Clear Skies!

 

ccs_hello



#106 Relativist

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Posted 25 May 2015 - 12:31 PM

The question is not if S/N is optimized, the question is if the S/N is optimized for imaging or for live viewing. For live (EAA type) viewing one could accept a lower S/N if it meant having a decent view vs. a dim or no view near real time.

It sounds like unless there is custom software/firmware that allows for manipulation of the gain setting them both cameras are equivalent in this way. In addition there is no way to know how much of any difference it will make.

Edited by Relativist, 25 May 2015 - 12:31 PM.


#107 ccs_hello

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Posted 25 May 2015 - 02:45 PM

Curtis,

 

Probably asking Atik directly (or check the manual) to see if analog gain is user adjustable (set thru MENU).

They use AFE and the AFE chip has config registers to change the gain setting.

It is where or not the astroCCD imager mfgs such as ATIK is willing to expose this to the end user.

 

AFAIK, the gain setting range is quite broad (so long as you can adjust it), such that the extra gain to get extreme gain is unnecessary (i.e., becomes too noisy.)

 

Clear Skies!

 

ccs_hello



#108 ccs_hello

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Posted 25 May 2015 - 02:49 PM

Also a good news for these astroCCD imagers are:

the data output sent to the PC is all in raw digital form, unprocessed.

 

Thus it is very easy to use the same image quality evaluation criteria to compare different models from various mfgs.

There is no thing to conceal.  It an imagers has a higher read noise under the same test conditions as others, it should be a good indication.

 

Of course, the magic on those should be the PC "Live" processing software. 

This should be under serious consideration.

 

Clear Skies!

 

ccs_hello



#109 Dom543

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Posted 25 May 2015 - 03:26 PM

I asked and Kyle replied that AstroLive should be working with all ATIK cameras. He used it with some ATIK's but haven't had a chance to test the 414ex.

 

The situation is almost identical for the SX825. Paul says that LodestarLive should work with all SX cameras. When loading the software, one should add some command line options that specify the parameters of the sensor. But Paul doesn't have an SX825 and hence hasn't tested it.

 

Clear Skies!

--Dom


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#110 Relativist

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Posted 25 May 2015 - 03:43 PM

Thanks Dom, that's useful information thanks. I sure wish someone would do a shootout of those cameras for EAA use.



#111 Dom543

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Posted 25 May 2015 - 04:10 PM

Curtis,

They should be pretty close. Both SX and ATIK are experienced astro camera makers with long track records. They know how to bring out the best from a given sensor.

Interestingly, Kyle warned me that I might be disappointed, when switching to the ATIK414ex from the Lodestar x2. Higher resolution yes but at the expense of substantially longer integrations. Makes sense, you don't get anything of value for free. The issue is not of urgent importance for me as I don't have the loose $1600 itching in by pocket...

 

Clear Skies!

--Dom



#112 Alex Parker

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Posted 25 May 2015 - 04:47 PM

Curtis,

They should be pretty close. Both SX and ATIK are experienced astro camera makers with long track records. They know how to bring out the best from a given sensor.

Interestingly, Kyle warned me that I might be disappointed, when switching to the ATIK414ex from the Lodestar x2. Higher resolution yes but at the expense of substantially longer integrations. Makes sense, you don't get anything of value for free. The issue is not of urgent importance for me as I don't have the loose $1600 itching in by pocket...

 

Clear Skies!

--Dom

 

I've been toying with the idea of an SX 674 an an upgrade from the Lodestar.  It has a chip with a very similar QE curve to the Lodestar, so should offer good sensitivity.  It has 4.5 micron pixels, so IF 2x2 on-chip binning was available it could I imagine function much like a larger Lodestar.  Or, for brighter objects, present both a larger sensor and finer pixel pitch.  If I get close to talking myself into spending the $$$ I will of course report back here what happenes...



#113 Don Rudny

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Posted 25 May 2015 - 07:17 PM

 

Curtis,

They should be pretty close. Both SX and ATIK are experienced astro camera makers with long track records. They know how to bring out the best from a given sensor.

Interestingly, Kyle warned me that I might be disappointed, when switching to the ATIK414ex from the Lodestar x2. Higher resolution yes but at the expense of substantially longer integrations. Makes sense, you don't get anything of value for free. The issue is not of urgent importance for me as I don't have the loose $1600 itching in by pocket...

 

Clear Skies!

--Dom

 

I've been toying with the idea of an SX 674 an an upgrade from the Lodestar.  It has a chip with a very similar QE curve to the Lodestar, so should offer good sensitivity.  It has 4.5 micron pixels, so IF 2x2 on-chip binning was available it could I imagine function much like a larger Lodestar.  Or, for brighter objects, present both a larger sensor and finer pixel pitch.  If I get close to talking myself into spending the $$$ I will of course report back here what happenes...

 

Hi Alex,

 

Just a few suggestions before you take the $2200 plunge.

 

Check out the icx674 sensitivity specs against the icx829.  It appears the 829 has four times the sensitivity of the 674. 3200mv v 800mv.

 

What resolution would you get with 2x2 binning?  Doesn't seem much better than the Lodestar.

 

Check out what optics are needed to get the same image scale as the Lodestar.  The larger sensor will require longer optics to get the same scale.  The result is slower or more expensive or both.  You can crop, but then it negates the res gain.

 

What software do you use?  LL is specifically designed for EAA with on the fly dark frame subtraction and stacking.  Nebulosity 3 is a great program, but geared toward imaging with post processing stacking and image enhancements.

 

No doubt the camera will produce stunning images.  At what cost besides money?  Speed and simplicity.  You lessen the NRT experience and require guiding and long multiple exposures to get decent results.  Sounds more like imaging to me.

 

These are just some thoughts that I have had in the past looking at these same cameras, searching for the Holy Grail of EAA.  



#114 ccs_hello

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Posted 25 May 2015 - 08:21 PM

Wow $2200.  That's a lot of money, close to SONY A7s territory.

 

Clear Skies!

 

ccs_hello



#115 Relativist

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Posted 25 May 2015 - 08:34 PM

An A7s can be easily had used for that price. In fact even the Atik 414 isn't that much less than a used A7s. That said they are much different cameras and chip format, so they would likely be for much different telescopes.



#116 DonBoy

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Posted 25 May 2015 - 09:38 PM

I posted in the image gallery here several live stacked images using the Atik 414EX color from last Friday and Saturday. 

 

http://www.cloudynig...15#entry6603284


Edited by DonBoy, 26 May 2015 - 06:42 PM.

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#117 Relativist

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Posted 25 May 2015 - 09:58 PM

I posted in the image gallery here several live stacked images using the Atik 414EX color from last Friday and Saturday. 

 

http://www.cloudynig...15#entry6603329

 

Very nice Don, I like all of them! This will be a good method to evaluate cameras generally for EAA use as well.



#118 DonBoy

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Posted 25 May 2015 - 11:02 PM

Thanks Curtis.  Time can be cut down quit a bit if one has a larger aperture.  A C11 @ f3.3 would give almost the same image size but exposure could be reduced by 2.3  to get a comparable exposure as the C8@f5; thus a 180sec image could be reduced to 80sec with the C11 @f3.3. 



#119 budman1961

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Posted 25 May 2015 - 11:14 PM

Don,

 

I watched both of your NSN broadcasts, and your results are nothing short of exemplary.  The Atik 414EX is a fine CCD camera, and with the AT add-in, presents good live images.

 

Thanks for all you do!

 

Andy



#120 DonBoy

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Posted 25 May 2015 - 11:22 PM

Thanks Andy, your comments are very much appreciated.



#121 Relativist

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Posted 25 May 2015 - 11:44 PM

Thanks Curtis.  Time can be cut down quit a bit if one has a larger aperture.  A C11 @ f3.3 would give almost the same image size but exposure could be reduced by 2.3  to get a comparable exposure as the C8@f5; thus a 180sec image could be reduced to 80sec with the C11 @f3.3. 

 

Good point, I was playing with the telescope display in Skysafari and it turns out that the framing of my MCX2 with my AT8IN would be just about the same if I reduced my AT12IN by 0.75x with an ICX 825 camera. That would be at f/3 with such a setup.

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#122 budman1961

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Posted 25 May 2015 - 11:54 PM

Curtis

 

I look forward to seeing some images from you soon!

 

Andy



#123 Relativist

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Posted 26 May 2015 - 12:03 AM

Thanks Andy. Wish I had an ICX 825 camera to try, but I don't have one yet. Although I have plans to try the Sony a5100 on my AT12IN once the clouds clear and my dovetail supports come in.

 

P.S. I did a similar thing with a hypothetical scope and the A7s, it will need something like 128" focal length to have similar framing. Since the A7s has the ability to be used at high ISO settings a scope like a 20" f/4 with a 1.6x barlow could work (assuming the barlow could fully illuminate the chip).

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Edited by Relativist, 26 May 2015 - 12:20 AM.


#124 PiotrM

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Posted 08 August 2015 - 08:04 AM

Check out the icx674 sensitivity specs against the icx829.  It appears the 829 has four times the sensitivity of the 674. 3200mv v 800mv.


How does QE relates to sensitivity given in mV?

#125 DonBoy

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Posted 08 August 2015 - 01:41 PM

 

How does QE relates to sensitivity given in mV?

 

This may help answer your question:

 

http://www.andor.com...ors-to-consider




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