Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

CMOS sensors for EAA

  • Please log in to reply
132 replies to this topic

#26 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 11:17 AM

 

 

Wasn't it determined that the reduced 'amp glow' 'hack' was a desirable feature for EAA? Was our conclusion about that somehow wrong?

Sorry don't understand your comment. Yes, of course it is desirable. Not sure where I said it was not.

It is not a hack per se but rather required modifying the control logic of the SoC. Not that complicated to do and no unique or patentable IP here.

Another very important point to note is that you can only apply this trick to the 224 because the SoC supports powering down certain blocks during exposure. The camera manufacturer can do nothing about Amp Glow if the SoC does not support it. Also this feature is available to all camera manufacturers who use the SoC. It is just control logic.

I hope this helps answer your question.

Well it was sort of by exclusion, since such was not included in the list you had previously. Anyway, from memory, people were told to send their cameras back to get the 'amp glow reduction' feature added, which implies a hardware element.

I would also think that the overall qc procedures and selection of electronic components could make a difference in robustness of a particular camera. Engineering a decent optical window and cooling would also be important.

 

Yes, this is hardware based. I thought I said that above. But note this is not a feature designed by the camera manufacturer. It needs to be supported by the SoC in the first place. Better mechanicals / design also helps. This is very simple control logic.

 

Absolutely, I agree with you that better mechanicals (optical window, QC, cooling) make a big difference. That is exactly what I said in my first post.



#27 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 11:25 AM

Again, let me re emphasize... I am not saying you cannot differentiate (See my first post in this thread), but by its very nature a full System on Chip (SoC) by Sony is designed to minimize performance variations across cameras and devices that use that sensor. The ultimate goal being for device & camera makers to be able to focus on end market features rather than spending R&D on integrating the core sensor.

 

I have in front of me full schematics of these SoCs (under NDA) and believe me they take care of almost everything.

 

Camera manufacturers of course will fight commoditization and claim they can still differentiate... it is just that the vectors of differentiation now need to be different to CCDs which was my point.


Edited by Astrojedi, 30 August 2017 - 11:33 AM.


#28 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 12:00 PM


 

For the above argument to be true (ie. no significant performance difference between cameras with the same CMOS sensor) then it would also have to be true that all the items above listed below the sensor must have no impact on camera performance.  I'm sorry but I just can't believe that is the case.  In light of the small percentage of the physical package made up by the sensor I firmly believe there is a lot of opportunity for a camera manufacturer to inject their own IP to produce a camera with performance different than their competitors.  In terms of how this applies to Mallincam, I don't see how it is possible for anybody here to know with certainty one way or another that there is none of Rock's IP inside the digital cameras he sells.  Arguing for or against is moot, so let's stop talking about it.  The only information that is relevant are actual observations by users.

 

Regards,

 

Jim T.

 

 

Also note this thread is about CMOS cameras from all manufacturers and not specific to MC. Please don't bring MC into this as I really don't want to talk about MC. 

 

As a skeptical and informed consumer if I am paying a premium for a camera (or any product for that matter) I would like to know what I am getting for my money. This is not specific to any camera manufacturer. I would critically evaluate any camera (or any product I buy) in the same way.


Edited by Astrojedi, 30 August 2017 - 12:02 PM.


#29 Relativist

Relativist

    Cosmos

  • *****
  • topic starter
  • Posts: 8151
  • Joined: 11 Oct 2003
  • Loc: OC, CA, USA

Posted 30 August 2017 - 01:07 PM

Curtis,

Yes, those CMOS SoC (system on chip) image sensor systems are all digital and (almost) 100% self-contained.
Hehe, actually 99%.

Smart guys such as Dr. Qiu (the QHY fame) had figured out few tricks to squeeze out a bit more, some undocumented SoC features and some pure electronic tricks (to push beyond spec.)
These are dark secrets or real IPs, but not hard to learn.
Others who play in the astro-camera field soon follow suit. Security cam mfrs usually don't care about these niche features.

What does matter:
- lower thermally generated noise (some mistakenly call it amp-glow), even in long exposure
- push max exposure time beyond what is documented in SoC's datasheet

Others are trivial ones but often overlooked by "video" camera/security cam mfgs:
- not even bother to investigate into any form of long exposure (security cam industry does not like smeared images/fuzzy faces)
- do not switch SoC out of movie/video mode into (multiples of) one-shot image-taking mode
- do not understand some image sensors have HCG mode and (clueless thus not) willing to take advantage of it

Clear Skies!

ccs_hello


So this is as suspected, the point is that the implementation matters greatly. I recall searching for any camera and noted that there were car backup cameras that used the 224, but that the implementation was not conducive to EAA use.

I think we can safely say that the SoC nature of CMOS certainly levels the playing field for all manufacturers that intend on building an astronomy capable camera as Hiten has pointed out. The rest is really up to us and besides some rudimentary camera design tasks the difference for many is what the software can do.

One of the reasons I started this thread was to determine if an EAA centric DIY camera project based on the IMX 385 is worth pursuing. So far from what has been said here it makes a lot of sense to me to consider developing something like a Rasberry PI camera module based on the IMX 385.
  • 42itous1 likes this

#30 jimthompson

jimthompson

    Apollo

  • *****
  • Posts: 1087
  • Joined: 06 Oct 2009
  • Loc: Ottawa, Canada

Posted 30 August 2017 - 01:25 PM

 

Also note this thread is about CMOS cameras from all manufacturers and not specific to MC. Please don't bring MC into this as I really don't want to talk about MC. 

 

As a skeptical and informed consumer if I am paying a premium for a camera (or any product for that matter) I would like to know what I am getting for my money. This is not specific to any camera manufacturer. I would critically evaluate any camera (or any product I buy) in the same way.

 

It is agreed then that we shall not talk specifically about MC products any more in the context of this thread.  I am happy with that.  I only appear to defend them because few others will, and without equal representation you get a biased group as a result.  For this agreement to hold there can be no more statements about how it is hard to justify the additional expense for one camera supplier over another since they both use the same CMOS sensor and therefore must fundamentally supply the same camera.  Based on the discussion above it would seem implementation is everything.  No more speculation, only actual test results please.

 

Regards,

 

Jim T.


  • will w likes this

#31 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 01:38 PM

Jim,

 

Just FYI... I am not speculating here or on any other threads. This is my area of expertise and I am happy to debate the physics and fundamentals with anyone who wants to do it in a scientific way.

 

The statements made above are true for MC or any other camera manufacturer who uses CMOS.

 

Also there seems to be a lot of mis-characterization of my statements and strawman arguments that are made. No one is saying that a camera manufacturer should not be able to charge a premium based on the differentiation of their products. But I would like to understand what that is and the camera manufacturer should be able to explain it especially if they want to charge a premium. There is not a single feature of the camera that I can point to which justifies that premium.

 

Also it is quite straightforward for a subject matter expert to find out whether there is unique IP in a product. This is not as mysterious as you make it sound.

 

Your statement above is basically telling everyone that take it on faith that MC cameras have a differentiation worth paying that premium for.

 

And lastly, the is the second time you have done this in this thread... stop telling others what they can and cannot discuss on these forums.


Edited by Astrojedi, 30 August 2017 - 01:40 PM.


#32 jimthompson

jimthompson

    Apollo

  • *****
  • Posts: 1087
  • Joined: 06 Oct 2009
  • Loc: Ottawa, Canada

Posted 30 August 2017 - 02:01 PM

I have been trying Hiten to keep my posts worded in a general sense, not specifically addressed to you, but have evidently failed to do so in your eyes.  I can not help that you take what I say as an attack on yourself personally, that is not my intention.  Maybe you could read again my posts, as you have told us to do of yours, and try to understand them from the perspective of somebody not trying to attack you, just somebody looking for a balance in the discussion.

 

I am not asking people to take MC products on faith.  It is ironic you would write such a statement when you are asking us to take what you say on faith because of your background.  I think I made it pretty clear that the only truth is in real testing of hardware.  Adding speculation and comments based more on feelings does nothing to answer the original question:  is this a good camera or not?  If you want us to be skeptical of what we read on camera retailer websites, you have to accept that we will also be skeptical of what you or other group members post here on the group as well.

 

Regards,

 

Jim T.


  • will w likes this

#33 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 02:17 PM

Jim, there is no speculation on this thread on MC cameras so not sure why you felt the need to make that comment. You have taken this thread completely off-topic.

 

Also I have never asked anyone to take what I say on faith. That is the beauty of science. You can independently validate it.

 

Lets start a new thread and why don't you tell me about a feature that MC CMOS cameras have that other manufacturers don't that justifies the premium? And lets subject that to scientific inquiry.

 

I want to know what this secret sauce or magic dust is that it is impossible for a reasonably intelligent person to understand. Unless you are asking me to buy MC cameras on faith.


Edited by Astrojedi, 30 August 2017 - 02:38 PM.


#34 jimthompson

jimthompson

    Apollo

  • *****
  • Posts: 1087
  • Joined: 06 Oct 2009
  • Loc: Ottawa, Canada

Posted 30 August 2017 - 03:13 PM

Hiten,

 

A few quotes from this thread alone (in reverse order) that ask us to believe what you have said is true:

 

"Just FYI... I am not speculating here or on any other threads. This is my area of expertise and I am happy to debate the physics and fundamentals with anyone who wants to do it in a scientific way."

 

"I have in front of me full schematics of these SoCs (under NDA) and believe me they take care of almost everything."  <--- I like this one the most

 

"I and our engineering teams work with these sensor SoCs all the time. This is my field of work."

 

With regards to your challenge, please recall the statement I made in the now locked DS2.3+ thread which stated that I have not found a commercial supplier for a generic version of the DS2.3+ with IMX302 sensor.  This makes it rather difficult to do a back to back test.  All I am able to do is test and report on the MC version in the context of all the other cameras I have used in the past.  I don't have the resources to invest in numerous versions of cameras using the same sensor, so I'm afraid those test results won't be coming from me unless somebody wants to lend me their camera (eg. IMX224 based cameras).  The only way I was able to do the ICX825 camera comparison was through the generous loaning of cameras from Joe S. and Rock.

 

Do the MC versions of Touptek cameras have a "secret sauce"?...I don't know, but neither do you regardless of your background.  In the meantime new customers will just have to make their choices based on the information that is available like product reviews or user testimonials.

 

Regards,

 

Jim T.


  • will w likes this

#35 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 03:33 PM

Hiten,

 

A few quotes from this thread alone (in reverse order) that ask us to believe what you have said is true:

 

"Just FYI... I am not speculating here or on any other threads. This is my area of expertise and I am happy to debate the physics and fundamentals with anyone who wants to do it in a scientific way."

 

"I have in front of me full schematics of these SoCs (under NDA) and believe me they take care of almost everything."  <--- I like this one the most

 

"I and our engineering teams work with these sensor SoCs all the time. This is my field of work."

 

With regards to your challenge, please recall the statement I made in the now locked DS2.3+ thread which stated that I have not found a commercial supplier for a generic version of the DS2.3+ with IMX302 sensor.  This makes it rather difficult to do a back to back test.  All I am able to do is test and report on the MC version in the context of all the other cameras I have used in the past.  I don't have the resources to invest in numerous versions of cameras using the same sensor, so I'm afraid those test results won't be coming from me unless somebody wants to lend me their camera (eg. IMX224 based cameras).  The only way I was able to do the ICX825 camera comparison was through the generous loaning of cameras from Joe S. and Rock.

 

Do the MC versions of Touptek cameras have a "secret sauce"?...I don't know, but neither do you regardless of your background.  In the meantime new customers will just have to make their choices based on the information that is available like product reviews or user testimonials.

 

Regards,

 

Jim T.

 

Totally lost as to the point you are making. I was demonstrating my source of information and my background. You don't even have that and neither can you articulate a single feature that is unique to MC yet you keep defending MC cameras. The irony of you claiming bias is not lost on me.

 

Also this thread has nothing to do with MC cameras. You are the one who started talking about MC cameras and making insinuating statements. It is me who is wondering where are the mods.

 

Can we please stop talking about MC and get back on topic.



#36 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 03:50 PM

 

Curtis,

Yes, those CMOS SoC (system on chip) image sensor systems are all digital and (almost) 100% self-contained.
Hehe, actually 99%.

Smart guys such as Dr. Qiu (the QHY fame) had figured out few tricks to squeeze out a bit more, some undocumented SoC features and some pure electronic tricks (to push beyond spec.)
These are dark secrets or real IPs, but not hard to learn.
Others who play in the astro-camera field soon follow suit. Security cam mfrs usually don't care about these niche features.

What does matter:
- lower thermally generated noise (some mistakenly call it amp-glow), even in long exposure
- push max exposure time beyond what is documented in SoC's datasheet

Others are trivial ones but often overlooked by "video" camera/security cam mfgs:
- not even bother to investigate into any form of long exposure (security cam industry does not like smeared images/fuzzy faces)
- do not switch SoC out of movie/video mode into (multiples of) one-shot image-taking mode
- do not understand some image sensors have HCG mode and (clueless thus not) willing to take advantage of it

Clear Skies!

ccs_hello


So this is as suspected, the point is that the implementation matters greatly. I recall searching for any camera and noted that there were car backup cameras that used the 224, but that the implementation was not conducive to EAA use.

I think we can safely say that the SoC nature of CMOS certainly levels the playing field for all manufacturers that intend on building an astronomy capable camera as Hiten has pointed out. The rest is really up to us and besides some rudimentary camera design tasks the difference for many is what the software can do.

One of the reasons I started this thread was to determine if an EAA centric DIY camera project based on the IMX 385 is worth pursuing. So far from what has been said here it makes a lot of sense to me to consider developing something like a Rasberry PI camera module based on the IMX 385.

 

Yes, implementation does matter, always have and always will. But SoCs have really reduced the development burden on the camera maker. I think a DIY camera module is definitely viable. Have you given any more thought to the platform e.g. Linux or Android etc.? It will require some low level programming since the drivers are typically provided by the camera manufacturer.

 

I am interested in dabbling with a Unistellar type DIY kit with more of an eyepiece form factor. The projection hardware is a little expensive though.



#37 A. Viegas

A. Viegas

    Mercury-Atlas

  • *****
  • Posts: 2988
  • Joined: 05 Mar 2012
  • Loc: New York City/ CT

Posted 30 August 2017 - 04:02 PM

There are new CMOS sensors coming very soon to the EAA /AP market. I think we are all very lucky to have this new technology for our hobby. Regardless of branding the real winners we the consumers because we get far better overall performance for a fraction of the cost. CMOS trumps analog video and traditional CCD in price to performance. More importantly there is much more focus and energy now in the development of low light sensors which are perfect for EAA!!! Stay tuned!


Al
  • will w and jimthompson like this

#38 JPKellysr

JPKellysr

    Messenger

  • *****
  • Posts: 443
  • Joined: 26 Feb 2015
  • Loc: Genoa, Nevada, USA

Posted 30 August 2017 - 04:18 PM

Here is a website with information on new astronomy CMOS sensors:

 

http://www.astrocmos.com/



#39 Relativist

Relativist

    Cosmos

  • *****
  • topic starter
  • Posts: 8151
  • Joined: 11 Oct 2003
  • Loc: OC, CA, USA

Posted 30 August 2017 - 04:23 PM

1. There in no prohibition here about talking about any particular camera vendor. I do not see the discussion as off topic since those are merely specific examples of the general topic here in this thread (CMOS cameras).Therefore no moderation is required unless people start getting rude and I expect all of us to be adult enough not to do that.

2. Finally we're getting somewhere where I think we can all agree, which is an IMX 385 based EAA DIY project. What I was thinking specifically is we build a board much like the following link for the Rasberry Pi platform. We would want the board done in such a way to allow for direct sensor cooling and mounting to a case. Otherwise whatever people code into Python would be available. This would allow for either a wrap around driver (like ASCOM) or for a more straightforward implementation, like saving files for display by Astrotoaster.

https://www.adafruit.com/product/3100

3. Note that the camera in the link above can be modified to remove the lense so it can be at prime focus. I'm considering testing it at f/2 for EAA.

#40 alphatripleplus

alphatripleplus

    ISS

  • *****
  • Moderators
  • Posts: 67669
  • Joined: 09 Mar 2012
  • Loc: New Jersey

Posted 30 August 2017 - 04:44 PM

I agree with Curtis. Indeed, I would remind everyone that that the CN Terms of Service ask us to "play nice", "be polite", "be tolerant", among other things. Perhaps everyone should read through their posts and consider whether they have met that standard. Disagreements are fine, but please exercise restraint and respect when responding to other posts that you don't agree with.

 

End of sermon.



#41 JPKellysr

JPKellysr

    Messenger

  • *****
  • Posts: 443
  • Joined: 26 Feb 2015
  • Loc: Genoa, Nevada, USA

Posted 30 August 2017 - 04:44 PM

Here is a great example of added value:

 

What new from QHYCCD…

QHY168C is a color cooled APS-C camera with SONY sensor. We can not count on SONY to make mono version so… QHY make next step and professionally “debayered” colour sensor to get clear mono!

On attached photo all boards has debayered sensors – only middle one is colour.

Great news. We are waiting for first tests.

Mono version should be available soon in the same price as colour version – $1499.

 

http://www.astrocmos...camera-as-mono/



#42 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 04:55 PM

Here is a great example of added value:

 

What new from QHYCCD…

QHY168C is a color cooled APS-C camera with SONY sensor. We can not count on SONY to make mono version so… QHY make next step and professionally “debayered” colour sensor to get clear mono!

On attached photo all boards has debayered sensors – only middle one is colour.

Great news. We are waiting for first tests.

Mono version should be available soon in the same price as colour version – $1499.

 

http://www.astrocmos...camera-as-mono/

Will be really interesting if QHY gets it right. Debayering the sensor also potentially destroys the microlenses which impacts QE. I am hoping QHY has figured out a way around this.



#43 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 05:17 PM

Curtis,

 

There are multiple steps to achieve what you want with IMX385. Starting from a Sensor SoC is doable and offers the most flexibility but will require quite a bit of work. IMX385 boards may be available on Alibaba but I have not checked yet.

 

If not, you will have to figure out how to interface the SoC to the Pi. Since the SoC supports LVDS or MIPI D-PHY interfaces you will need a LVDS or D-PHY driver board which can then talk to the Raspberry PI. Will need you to write low level drivers to drive the PHY (physical layer) and the link and higher layers. Soldering skills will come in very handy.

 

ASCOM only exists on windows. A custom driver on linux probably makes more sense.If you want to use the camera from windows a higher level protocol makes more sense.

 

Hiten



#44 JPKellysr

JPKellysr

    Messenger

  • *****
  • Posts: 443
  • Joined: 26 Feb 2015
  • Loc: Genoa, Nevada, USA

Posted 30 August 2017 - 08:26 PM

 

Here is a great example of added value:

 

What new from QHYCCD…

QHY168C is a color cooled APS-C camera with SONY sensor. We can not count on SONY to make mono version so… QHY make next step and professionally “debayered” colour sensor to get clear mono!

On attached photo all boards has debayered sensors – only middle one is colour.

Great news. We are waiting for first tests.

Mono version should be available soon in the same price as colour version – $1499.

 

http://www.astrocmos...camera-as-mono/

Will be really interesting if QHY gets it right. Debayering the sensor also potentially destroys the microlenses which impacts QE. I am hoping QHY has figured out a way around this.

 

Even if 25% of the lenses are impaired it will be more sensitive than the color version.



#45 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 08:48 PM

 

 

Here is a great example of added value:

 

What new from QHYCCD…

QHY168C is a color cooled APS-C camera with SONY sensor. We can not count on SONY to make mono version so… QHY make next step and professionally “debayered” colour sensor to get clear mono!

On attached photo all boards has debayered sensors – only middle one is colour.

Great news. We are waiting for first tests.

Mono version should be available soon in the same price as colour version – $1499.

 

http://www.astrocmos...camera-as-mono/

Will be really interesting if QHY gets it right. Debayering the sensor also potentially destroys the microlenses which impacts QE. I am hoping QHY has figured out a way around this.

 

Even if 25% of the lenses are impaired it will be more sensitive than the color version.

 

How did you arrive at that conclusion? Is there a paper that you can share?



#46 JPKellysr

JPKellysr

    Messenger

  • *****
  • Posts: 443
  • Joined: 26 Feb 2015
  • Loc: Genoa, Nevada, USA

Posted 30 August 2017 - 08:57 PM

There are 3 types of sensors, red, blue, green. Assume all frequencies are of equal intensity (wrong of course). So each senor will only register about 1/3 of the light that hits it & will miss 2/3's. A monochrome sensor can register all of the impinging light (ignore QE for this.)

So 3 monochrome sensors (assuming 1/4 lost to damage) ought to be more sensitive than 4 color sensors. A real back of envelope ball park guess.



#47 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 30 August 2017 - 09:16 PM

Not a bad way to think about it but note that every pixel has a micro lens. The problem is that scraping off the Bayer filter also scrapes off the lens. Typically there is a 20-30% QE loss or sometimes more depending on the sensor. Not sure if QHY has found a solution around this or if that particular sensor lends itself better to debayering.


  • OleCuss likes this

#48 OleCuss

OleCuss

    Vanguard

  • *****
  • Posts: 2279
  • Joined: 22 Nov 2010

Posted 31 August 2017 - 04:55 AM

There are 3 types of sensors, red, blue, green. Assume all frequencies are of equal intensity (wrong of course). So each senor will only register about 1/3 of the light that hits it & will miss 2/3's. A monochrome sensor can register all of the impinging light (ignore QE for this.)

So 3 monochrome sensors (assuming 1/4 lost to damage) ought to be more sensitive than 4 color sensors. A real back of envelope ball park guess.

I'm really not at all sure it pencils out quite like that.

 

With the modern OSC sensors I think we are getting QEs more in the 40-60% range?  I see some cameras listing with a QE more like 80% but I'm not really sure I believe that.

 

Net effect is that if you are getting about a 50% QE from a OSC sensor you can't be getting only 1/3 the light you would get from a monochrome sensor.  I think that part of the reason for this is that the filters don't have abrupt cut-offs and actually allow a fairly broad spectrum of wavelengths to be collected by each pixel.

 

But I'm not the expert on this. . .



#49 Relativist

Relativist

    Cosmos

  • *****
  • topic starter
  • Posts: 8151
  • Joined: 11 Oct 2003
  • Loc: OC, CA, USA

Posted 31 August 2017 - 10:49 AM

It's not that simple, the QE number applies to the photons that hit the photocell, the photons have to make it past the Bayer filter first.
  • OleCuss likes this

#50 JPKellysr

JPKellysr

    Messenger

  • *****
  • Posts: 443
  • Joined: 26 Feb 2015
  • Loc: Genoa, Nevada, USA

Posted 31 August 2017 - 11:32 AM

I am sure the data must be there (I have even seen it somewhere). Red, green, blue, & monochromatic photosites have varying QE's & of course all wavelengths are not of equal intensity (which is why there are more green photosites.) It is a rough guess that I suspect is correct. In the CCD section there is some discussion on how much longer it takes to acquire an image with a OSC camera than a mono camera. That would be another way to approximate the relative sensitivities.

In any event, there is certainly reason to believe that they can produce an acceptable mono camera by removing the chromatic filters. It has been done before.

 

JPK




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics