PIER-1 ZWO 294mm Pro

Hi Steve,

Based on my knowledge, software and hardware binning generally are the same for CMOS sensors. The binning happens after the readout.  For reference:

https://www.photometrics.com/learn/imaging-topics/binning-2#:~:text=CMOS%20Binning&text=In%20CMOS%20the%20binning%20occurs,for%20that%20resulting%20super%E2%80%91pixel.

https://www.altairastro.help/info-instructions/cmos/how-does-binning-work-with-cmos-cameras/

One exception is 294MM (some newer cell phone sensors as well), which uses different ADC (12bit vs. 14bit) for 1x1 and 2x2 binning. 

I would prefer to keep the original 2x2 binning (definitely not 3x3 binning I believe that is using the 12bit ADC) if the guiding is capable of doing that. I don't mind oversampling, but the resolution is important for printing larger sizes.

Thanks

Steve,

It sounds like the default 2x2 binning gives the best performance. Let's leave it at that. 1x1 would (I think) be oversampled.

I have been waiting for almost 6 months to change the camera on Pier-1 while ZWO released a new range, to date we have nothing new. So as I have a 294MM Pro on the shelf shall we do that on my next trip. Please let me know your thoughts?

I also want to discuss the merits of leaving it at standard binning then you can software bin instead of hardware bin

Have any of you explored CMOS software binning yet ?

Steve

Good evening Steve and Pier1 syndicate members,

A small contribution to the debate:

A. 294MM versus 1600MM: I think this would be an upgrade as the Full well and QE are much in favour of the 294MM. Also at 14bits we will have more depth than at 12bits. The sensor are roughly the same size with a bit more width for the 294.

B. Regarding binning, and given the focal length of Pier1, I'd say that for the 294MM a bin1x1 would be great at a seeing of 1-2" FWHM or better. If the seeing is lower, then 2x2 is still be better option. Regarding the current camera, 2x2 is still the better option, I think.

Cheers

Manuel

The native binning of 294MM is 2x2, which yields 4.64 um pixel size and 12MP resolution.

The 1x1 binning of 294mm uses a 12bit ADC, yields 2.3 um pixel size and 47MP resolution.

I think there is no doubt Bin1 is not suitable for this Pier. I would only use Bin1 for ultra-widefield. The argument is between Bin2 and Bin4 (Bin3 has the same ADC from Bin1 so not an option either).

I would prefer Bin2 as software binning in post to Bin4 will provide the same results. I rather have the flexibility.

The native binning of 294MM is 2x2, which yields 4.64 um pixel size and 12MP resolution.

The 1x1 binning of 294mm uses a 12bit ADC, yields 2.3 um pixel size and 47MP resolution.

 

I think there is no doubt Bin1 is not suitable for this Pier. I would only use Bin1 for ultra-widefield. The argument is between Bin2 and Bin4 (Bin3 has the same ADC from Bin1 so not an option either).

I would prefer Bin2 as software binning in post to Bin4 will provide the same results. I rather have the flexibility.

 

This is my take on it also if I am honest 

it’s a great mount so I think we should see how it performs with the 294 at native 2x2binning. As it’s a far better camera in every aspect :)

cheers

steve

Steve 

Hi everyone,

I just analyzed the bin1x1 data captured on Pier 1 (ngc 7000 test). I am using APP.

Results from PI/SNRViews are:

Summary:

========

SNR = 44.48 db, K Bin1_Luminance (integrated under scale 1)

SNR = 45.32 db, K Bin1scale_Luminance (integrated with scale=0.5 in Tab 6 --> simulates bin2x2)

... So, the results are positive from my perspective.

Cheers

Manuel

Hi everyone,

I just analyzed the bin1x1 data captured on Pier 1 (ngc 7000 test). I am using APP.

Results from PI/SNRViews are:

 

Summary:

========

SNR = 44.48 db, K Bin1_Luminance (integrated under scale 1)

SNR = 45.32 db, K Bin1scale_Luminance (integrated with scale=0.5 in Tab 6 --> simulates bin2x2)

... So, the results are positive from my perspective.

 

Cheers

Manuel

Hi Manuel, for software 2x2, it might be better to use integer resampling. You can integrate first and then resample

In response to #5314

Thanks for your comment @kalemwo1994 ... and for further picking my curiosity about software binning. As a result I run a couple of tests to evaluate their effects on SNR.

Software used:

1. Integration: APP
2. Analysis and Resampling: PI

Methods and Results:

First I integrated the frames as they are (bin1) in APP. The SNR is 39.76 db. If I then IntegerResample (Resample factor = 2) this image, the SNR becomes 44.48 db. The overall best SNR however is the result of a Resample at 50% of this, i.e. 46.80 db.

I then loaded all raw frames into PI and performed an IntegerResample (RSf=2) on each of them (tedious) before integrating them with APP. The SNR is now 45.55 db. (The average SNR of the raw frames is 24.42 ± 0.38, the average SNR of the IntegerResampled frames is 30.29 ± 0.30.)

When I integrate the frames in APP and use a 0.5 scaling during integration, I get an SNR of 45.32 db.

Conclusion:

The best overall SNR comes from Resampling (not IntegerResample) the raw bin1 integrated image in PI with a ratio of 50%.

Using a 50% scaling during APP integration yields a result very close to integrating individually IntergerResampled (RSf=2) frames. In both cases, it is better than to IntegerResample the bin1 integrated image by about 1 db and a bit more than 1 db worse than a 50% Resample of the bin1 integrated image.

So overall, using the Resample method in PI yields a Amplitude ratio improvement of 30% over IntegerResample and an improvement of 18% versus scaling during APP integration.

What remains to be evaluated, is the effect of these differences on image processing following channel integration.

Cheers

Manuel