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Ultrastar Mono x2 Binning

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I decided to do an unscientific test to compare the difference in sensitivity between x2 binned and unbinned 825 captures. This is from a few days back. The images were taken through a light layer of clouds with the moon out and no LP filter from a red/white LP zone so only treat this as a relative comparison. Once the clouds clear I will share better captures.

With x2 binning the 825 mono sensor presents 13 micron pixels which increases the sensitivity of the sensor significantly and provides excellent sampling at f5 and f6. I found that sub exposures of 10s were sufficient for even the faintest objects at F5 on my C8 but typically did not need more than 5s sub exposures for most objects.

Based on a purely subjective visual assessment I found the 825 mono with x2 bin to be slightly more sensitive than the Lodestar X2M. But will do a head to head soon.

All captures using C8@F5 on my Evolution mount.  Used AT for stacking as Starlight Live does not yet support binning.

First up: Abell 539 unbinned vs. binned (note the x2 binned is half the total exposure time)


Some more captures at F5 using x2 binning. Unfortunately most of these stacks have clouds passing through. Especially evident in the NGC520 image.




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Thanks for sharing your results. So in theory the Ultrastar 2x binned is slightly more sensitive than the Lodestar X2 but twice the resolution even at 2x binning? Looking forward to seeing the 'head to head'. :)

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Thanks Rob, laudropb.


With x2 binning the resolution of the 825 is very similar to the X2 (the images above are the actual resolution. No re-sizing).

In my view the advantage of binning with the 825 is that it gives me 2 cameras in one. Without binning I get a larger FOV and finer pixels for wide-field imaging of larger DSOs at shorter focal lengths. And with x2 binning I get the sensitivity I enjoyed with the X2 for hunting down small faint galaxies and DSOs.


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Hiten - my post on a similar theme from last Aug 15 binning 2x2 - 8x8 via SX s/w ;-)



Thanks Nytecam. I did read that post. Very informative. I wanted to try out x2 binning and do some head to head comparisons on various objects to continue the discussion. I think the fact that 825 mono with x2 binning is by far one the most sensitive sensors out there at that resolution is still underappreciated.

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Hiten,  I know you told me that your color 825 camera when 2x binned didn't provide good b&w results.  Was that because the image quality was poor, or the sensitivity was so low that it required long exposures.  If the reason was longer than desired exposure times was the image atleast acceptable?


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I was comparing to the mono sensor. Resolution and sensitivity both suffer due to the RGB matrix. Hard to quantify but the image was not very good. Again that is subjective. Some folks may find it acceptable.

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Not just reduced sensitivity, sharpness, contrast - the apparent fidelity of the OSC image suffers in comparison to the mono camera. This due to the Bayer Matrix and the fact that de-mosaicing has to interpolate between pixels when the image is de-bayered.


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