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Hi! Is the flow cell analyzed in one go per base (as a whole), or scanned one part of the flow cell at a time, until all bases have been identified? How many cameras are there in llumina's instruments to image the flow cell? Thanks in advance!
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As far as I understand, the MiSeq, HiSeq 2500, and HiSeq 4000 each have a single camera. The flow cell is divided into lanes, swaths (left/right/center depending on the machine), surfaces (top and bottom), and tiles. A single tile is imaged at a time, except during focusing. The camera moves up a swath, imaging each tile's top surface. It does all the swaths for the top surface, then goes back and does the bottom surface for each tile.
The NextSeq is slightly different, with six cameras/sensors working as a single module, simultaneously imaging six different tiles.
I can't speak to the NovaSeq or iSeq. -
Thanks
Thanks a lot for the good answer, it helped a lot!Comment
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I do know Hiseq 2500's have two cameras. Here's a picture of the optical deck in case anyone is interested. You can see the green and red lasers at the left and top and the two cameras at angles on the right.
Click for bigger version.
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I’m not a sequencing expert. I’m a purification scientist who uses NGS to evaluate workflows my group develops. With this perspective, we think about the sample first and the NGS workflow second. The sequencer is an exceptionally honest reporter, but it can only report on what you give it, so whether you get clean, interpretable data from an NGS workflow is largely determined before you begin.
Here are nine questions we think about, in roughly the order they matter, before...06-18-2026, 07:11 AM -
Data variability is still an issue in sequencing technologies despite the advances in reproducibility and accuracy of these platforms. But the problem does not originate in the sequencing itself, but in the previous steps, before the sample reaches the sequencer.
The first step is collection, followed by preservation and sample preparation for analysis. Most scientists overlook those steps, but not being careful might just be skewing the experiment’s results.
...06-02-2026, 10:05 AM
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