Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Electronically Assisted Astronomy

Pages: 1 | 2 | (show all)
ccs_hello
Postmaster
*****

Reged: 07/03/04

Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: mmalik]
      #5733586 - 03/15/13 07:58 AM

EMCCD is an extreme high gain device on the source end, thus noise control is ultimate important. The TI device was produced a decade ago and TI is not a main stream CCD sensor producer thus some drawbacks are expected.
On the other hand, use what you can get (so long as not overly expensive) is the name of the game.

RE: Canon marketing claim on its sensor's sensitivity...
No technology disclosure was made thus I suggest treat it as a grain of salt.

My personal view: unless there is something new, (e.g., prepare to file patent thus cannot disclose), new sensor chip is just using the larger pixel area to fish for more photons. In that case, the new Canon sensor, just like other astroimaging devices you mentioned (both are using the regular commercial SONY CCDs), are still subject to absolute QE < 1 limitation. I.e., no way to overcome the law of physics.

Clear Skies!

ccs_hello


Post Extras: Print Post   Remind Me!   Notify Moderator  
nytecam
Postmaster


Reged: 08/20/05

Loc: London UK
Re: CCD vs. CMOS Video (DSO Astronomy) [Re: ccs_hello]
      #5735557 - 03/16/13 05:51 AM

Quote:

My personal view:.....new sensor chip is just using the larger pixel area to fish for more photons. In that case, the new Canon sensor, just like other astroimaging devices you mentioned (both are using the regular commercial SONY CCDs), are still subject to absolute QE < 1 limitation. I.e., no way to overcome the law of physics. Clear Skies! ccs_hello


Well said - so all the "magic circuitry" and other gismos can't create more real electrons than original photons arriving on the sensor because no sensor is 100% efficent [QE=100%] in converting photons to electrons but some folk believe in magic

Post Extras: Print Post   Remind Me!   Notify Moderator  
mmalik
Postmaster
*****

Reged: 01/13/12

Loc: USA
Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: ccs_hello]
      #5739130 - 03/17/13 05:04 PM

Quote:

My personal view: unless there is something new, (e.g., prepare to file patent thus cannot disclose), new sensor chip is just using the larger pixel area to fish for more photons. In that case, the new Canon sensor, just like other astroimaging devices you mentioned (both are using the regular commercial SONY CCDs), are still subject to absolute QE < 1 limitation. I.e., no way to overcome the law of physics.





Technology is evolving and science is evolving; who is to say our understanding of quantum efficiency (which is just a calculated ratio...an estimated percentage of photons hitting a devices photoreactive surface) is going to stand the test of time. We are far from even understanding nature of photon itself (wave-particle duality); our standard model... of particle physics is far from being complete, part of it being theoretical and part experimental.


I really don’t know whether Canon's new chip has any value to video astronomy; it is just a good step forward in otherwise stagnant industry. Chips, their designs (large/small pixels alike), their efficiencies, how we measure those efficiencies “today”, etc. are an ever changing dynamics. We are far from scratching the surface of any laws of physics, let alone invoking them with our limited understanding. Regards


Post Extras: Print Post   Remind Me!   Notify Moderator  
TonyBegg
member


Reged: 08/13/12

Loc: Santa Fe, NM, USA
Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: mmalik]
      #5782188 - 04/06/13 04:57 PM

My understanding is that early work on lucky imaging at Cambridge University in the UK used EMCCD or E-cubed something CCDs and was definitely not doing just planetary imaging (with big telescopes). I believe the finder scopes on the AAT when it opened in 1974 used modified vidicon vacuum tube TV cameras and showed quite a lot of stars (this was before CCDs). I asked one of the high end astro CCD camera makers ($20,000+ cameras) at last year's PATS whether they intended to use EMCCD and the guy said that Scientific CMOS was better. Here we have a non-cooled CMOS with amazing performance. I would like to see some sort of heads-up device that mixes real time color images of DSOs with the visual experience (something of a registration challenge I fear). Video astronomy seems to me to be stuck and I welcome perhaps a new approach here from Canon.

Post Extras: Print Post   Remind Me!   Notify Moderator  
scout72
Pooh-Bah
*****

Reged: 05/12/08

Loc: SF Bay Area
Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: mmalik]
      #6089620 - 09/19/13 09:54 AM

Sample video from new Canon CMOS

Pretty cool...I have a Canon EOS C100 for non-astro film project, there is a firmware update coming in November to allow expanded ISO to 80,000....I will have to see if 1/3second at iso80k is enough for bright DSO and not TOO noisy.


Post Extras: Print Post   Remind Me!   Notify Moderator  
jambi99
sage


Reged: 08/14/10

Loc: Québec, Canada
Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: nytecam]
      #6090442 - 09/19/13 06:11 PM

What's even more funny is that in the security world, analog camera are supposed to be a "poor man solution". I don't understand why it should be that different for astro video application. Analog camera will be always cheaper to produce. That, even if you are using the highest component grade available.

Edited by jambi99 (09/19/13 06:12 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: scout72]
      #6090544 - 09/19/13 07:32 PM

Quote:

Sample video from new Canon CMOS

Pretty cool...I have a Canon EOS C100 for non-astro film project, there is a firmware update coming in November to allow expanded ISO to 80,000....I will have to see if 1/3second at iso80k is enough for bright DSO and not TOO noisy.



I'd be interested in the result of your test as well.
I measured some video astronomy cameras (not mine) ISO and they were in the ISO 25k to 100k range deoending on camera model.
None of them shows any DSO in 1/3 sec . For M42 they need at least 1-2sec (Again depending on camera).


Post Extras: Print Post   Remind Me!   Notify Moderator  
ccs_hello
Postmaster
*****

Reged: 07/03/04

Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: scout72]
      #6090651 - 09/19/13 09:16 PM

Just wish to note that
Canon C100 has the "super 35" format sensor and the actual imaging area is 24.6 x 13.8mm (28.2mm diagonal) where pixel picth is 6.4 µm. The senor has 3840x2160 RGBG configuration, using 2x2 quad pixel to deBayer to form one color pixel representation.

The Canon (to be produced) big image sensor has 19um pitch pixel with the actual imaging area 36.48 x 20.52mm (diag: 41.86mm.)
The senor has 1920x1080 RGBG configuration, using every single pixel to deBayer to build a color pixel representation.

Both are 16:9 aspect ratio sensors.

Clear Skies!

ccs_hello


Post Extras: Print Post   Remind Me!   Notify Moderator  
ccs_hello
Postmaster
*****

Reged: 07/03/04

Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: jambi99]
      #6090655 - 09/19/13 09:19 PM

Quote:

What's even more funny is that in the security world, analog camera are supposed to be a "poor man solution". I don't understand why it should be that different for astro video application. Analog camera will be always cheaper to produce. That, even if you are using the highest component grade available.




Production volume dictates R&D investment and final pricing. Security videocam industry is quite large, actually.

Clear Skies!

ccs_hello


Post Extras: Print Post   Remind Me!   Notify Moderator  
scout72
Pooh-Bah
*****

Reged: 05/12/08

Loc: SF Bay Area
Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: ccs_hello]
      #6091026 - 09/20/13 02:27 AM

Quote:

Just wish to note that




Duly noted! I know it is not even going to come close- 19um pixel pitch is wild...


Post Extras: Print Post   Remind Me!   Notify Moderator  
scout72
Pooh-Bah
*****

Reged: 05/12/08

Loc: SF Bay Area
Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: scout72]
      #6091041 - 09/20/13 02:47 AM

Okay- well- it is a super full and high moon right now but went ahead and pointed my c100 at M31- 200mm f2.8 at iso20,000- here is the result: http://www.youtube.com/watch?v=MKH3v-9seoU

Post Extras: Print Post   Remind Me!   Notify Moderator  
Dwight J
scholastic sledgehammer
*****

Reged: 05/14/09

Loc: Lethbridge, Alberta, Canada
Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: scout72]
      #6091046 - 09/20/13 02:58 AM

Too bad about the moon. I'd like to see that on a moonless night. Even so, it shows the nucleus and the orientation of the disk.

Post Extras: Print Post   Remind Me!   Notify Moderator  
ccs_hello
Postmaster
*****

Reged: 07/03/04

Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: scout72]
      #6091242 - 09/20/13 08:36 AM

Quote:

http://www.youtube.com/watch?v=MKH3v-9seoU



Brian,

What is the shutter time on that movie?

Clear Skies!

ccs_hello


Post Extras: Print Post   Remind Me!   Notify Moderator  
scout72
Pooh-Bah
*****

Reged: 05/12/08

Loc: SF Bay Area
Re: CCD vs. CMOS Video (DSO Astronomy) new [Re: ccs_hello]
      #6091531 - 09/20/13 11:11 AM

Quote:

What is the shutter time on that movie?




1/3 second - slow shutter mode on the c100
this was done with a custom Cinema profile in camera to pull dark areas
This is AVCHD file loaded to youtube directly from camera/ no processing and shows what I saw on the camera's screen


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
2 registered and 6 anonymous users are browsing this forum.

Moderator:  David Pavlich, JayinUT, Mr Greybush 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 4250

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics