Blooming is a dynamic of astronomical CCD chips where information spills from one pixel to the next and cascades down the columns of the array.  When a pixel reaches it's full well capacity - the level of complete saturation - the image gives blooms.  Sometimes the blooms aren't too bad, like in this raw, 5 minute red channel shot taken of the Rosette:

Prior to further processing, the blooms have to be fixed by using either the Clone tool in Photoshop or by using a "de-blooming" plug-in that will somewhat automate the process.   

Though you might not think that the blooms are a big deal, "non-anti-blooming" (NABG) cameras do have their negatives.  First, longer exposures and bright stars can cause severe blooms, such as in this shot of M42, also a 5 minute, RAW, red channel exposure:

These blooms are much harder to clean.  But not only that, any information beneath the blooms are lost permanently.

Second, because blooming is likely to occur, you are somewhat limited on the length of exposures you can make.  Even though your skies might allow for 30 minute shots, the camera will prevent you from anything longer than 15 minutes if the composition contains bright stars and objects.  In fact, some objects, like the Pleiades cannot be shot at all with these cameras.  That's because these objects have such a tremendous dynamic range between brightness levels.  In order to get faint details, you'd have to over-exposure the image, which causes severe blooms...and lost information.  

"Anti-blooming" does exist as an option in many of the cameras, which all but eliminates blooms from even the brightest of objects, but they do this at the cost of sensitivity and saturation levels. NABG cameras (without anti-blooming technology) hold twice as many photons per pixel and are more sensitive than their ABG brethren.  Practically speaking, this equates to 30% less exposure time for NABG cameras than ABG cameras, which is why people buy cameras without the anti-blooming technology...maximum signal is important to them.

My complaint regarding non-antiblooming cameras (NABG) is that even though exposure requirements are 30% less than that of an ABG camera, that time is more than made up for in processing the blooms!  

We can look at this by studying the approach you are likely to take with both camera types.  Let's say we are going to take a black and white (grayscale) of the aforementioned Rosette Nebula.  With the NABG camera, we'd probably plan out three, 10 minute exposures (30 minutes of total exposure time).  Any more than this and we'd lose information to blooming.   If we were doing the same image with an ABG camera, we'd need approximately 40 minutes of total image time to get the same level of signal as with the NABG image; however, because we can take longer exposures, we can take the image with either two, 20 minute shots, or even a single, 40 minute shot.  

So, you'd need an extra 10 minutes with the ABG camera to give the same amount of detail as with the NABG camera.  However, shorter exposures require extra processing time in fixing the blooms, not to mention the extra time required with simply stacking more images. The other aspect of this process that requires more time is that you normally have to wait a minute between individual exposures so that the guide star can settle down and you can begin the new exposure.  Of course, this isn't a problem if you are guiding with a separate guider. SBIG cameras often have two chips, one for imaging and a smaller one for guiding.  So, when the shutter is closed between exposures, the guidestar is temporarily lost.  The software allows you to establish some amount of time to reacquire the guidestar prior to beginning the next image.  Though the time isn't much (about 10 seconds), it still contributes to the extra time.

In summary, NABG cameras allow for maximum signal gain of very faint objects in the least amount of time.  While ABG cameras are slower, they make up for this time in processing.  Plus, I find ABG cameras to be much more fun to use, without the worries of information loss due to blooms.   

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