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M16 with C-14

 

http://www.stanmooreastro.com/images/M16hsm2015.JPG

C-14

10nm H-a filter

EMCCD exp = 200ms x 86k (out of 100k)


Stan
 

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Wonderful resolution Stan !

I was wondering if you had tries the new ASI224 camera ? It is doing wonder for Uranus and Neptune imaging. The read noise of the IMX224 sensor is only 1 e-, which is equivalent to EMCCD camera.

Best regards

Christian


Le 15/08/2015 21:28, stan_ccd@... [C14_EdgeHD] a écrit?:

http://www.stanmooreastro.com/images/M16hsm2015.JPG

C-14

10nm H-a filter

EMCCD exp = 200ms x 86k (out of 100k)


Stan
 

"wondering if you had tries the new ASI224 camera ?"


I used one last night for the 1st time.

It really looks like read noise is <1e-?and it?approaches the EMCCD/ICCD experience.

The notorious CMOS banding is still present but very muted.

It is a?very fine camera!


Stan
 

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Thanks for the feed back.

Very interesting :-)

Christian

Le 16/08/2015 16:37, stan_ccd@... [C14_EdgeHD] a écrit?:

"wondering if you had tries the new ASI224 camera ?"


I used one last night for the 1st time.

It really looks like read noise is <1e-?and it?approaches the EMCCD/ICCD experience.

The notorious CMOS banding is still present but very muted.

It is a?very fine camera!


Stan
 

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Inspiring to see what a C14 is capable of.
Rick

On Aug 15, 2015, at 2:28 19PM, stan_ccd@... [C14_EdgeHD] <C14_EdgeHD@...> wrote:
 

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Truly stunning! Congrats. - Thomas in New Mexico
 

maybe the best M16 I have seen.

-- benoit

On Sun, Aug 30, 2015 at 5:53 PM, Thomas Ashcraft ashcraft@... [C14_EdgeHD] <C14_EdgeHD@...> wrote:
?

Truly stunning!? Congrats.? -?? Thomas in New Mexico
 

Very impressive.

I visited the website

This looks like more than just a C14 and a CCD camera. It looks like the image also put an image intensifying camera in the imaging train in front of the CCD camera.


The system?relies on?very short exposures and long focal length or narrowband imaging where you can get a photo flux low enough to fit within a range where the image intensifying camera works in an individual photon counting domain. One strong benefit to this approach is that the individual exposures are short like we do for planetary imaging. Therefore, you can capture at the resolution of the telescope with minimal atmospheric blurring by selecting good frames. 5.5 hours of imaging adds up to high SNR and high resolution.


I have a few questions.

1. What focal length did you use for the image of M16?

2. How can you register individual frames with an SNR like the single frame shown for M57? The edges don't look?adequately defined.

3. How would a series of 5 second CCD?exposures (selected and?averaged for 5.5 hours) look compared with the intensified system at exposures of 200 ms. I ask because the SNR of a CCD looks as good as the intensified system when using exposures about?10 times longer than the photon counting exposure length.

4. I sense a possible product here.?Are you planning to produce systems for sale?


Andrew?
 

(sorry for the delayed response. I've been off-line for awhile)

The camera used for M16 is an "Electron Multiplied" CCD (EMCCD) in which the intensification?takes place inside the CCD, as opposed to Photon multiplication separate from the camera.? Both EMCCD and ICCD (ZeroCam) work via the same principle of boosting the real signal to overcome read-noise.

The M16 was taken with C-14 at prime FL (f/11).? Image scale = 0.42"/pix.

Frame registration is a big issue when there are no bright stars.? Benoit and I have devised some?unusual solutions that can take enormous amounts of computing time. Benoit's favored approach can take more than a day to optimally converge!? My usual method generally takes about 2-3x longer than the total exp-time but some images require Benoit's days-long methods.

Shorter sub-exps capture less seeing wander and thus result in a sharper stacked image.? Seeing wander occurs on virtually every time scale so shorter is usually better.? But bad seeing?produces?a disturbed?bloated PSF at?virtually every time scale and there is not much improvement faster than about?500-1000ms unless a de-speckling method is applied (I'm working on that).?If the detector really is "zero read-noise" then there is no S/N penalty for going too fast.

As for a "product", intensified cameras are very expensive and their operating hardware and software requirements are intimidating. Benoit and I have both acquired less expensive used lab-cameras and?written?our own?camera control software. So there?is a big hurdle to overcome.??We have received interested?inquiries from amateur astronomers?but to date?no one has followed thru.?

However, CMOS technology is improving to the point where there are some detectors with noise near 1e-, which starts to become amenable to these techniques.? sCMOS is very expensive but?there is new inexpensive Sony chip (incorporated into the new ZWO) that looks promising, except that it is small (pixels and detector) and only available as?Bayer at this time.? I may attempt marketing software to exploit that camera.

Stan

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