The pixel size comparison of two ASI cameras – Sunspot AR2665

In this short article, we compare two very popular cameras, ASI174 and ASI290. Particularly, we were testing the effect of the pixel size of each ASI camera. ASI174 has 5.86µm and ASI209 only 2.9µm of the pixel size. Why is pixel size so important? Camera with smaller pixel size adjusted at telescope with short focal length gives smother details on the image.
The test comparison was done by imaging the largest sunspot of the year 2017, AR2665 sunspot, at our ZWO observatory on the beginning of the July. Images were taken through 350-mm telescope at focal length 3556-mm. Image taken with ASI174 got scale 0.28 arcsec/px, and ASI290 got image scale 0.17 arcsec/px, respectively.
Despite that image taken with ASI290 has smaller field of view, only 5×3 arcmin, but gives more details, as seen on the image below. As a result of the test, we suggest that if you have moderate observing conditions, use camera with smaller pixel size and telescope with short focal length, then you could expect to get more details on the image.

Here is some tehnical details for both compared images and you can also download both raw videos (5 GB). Please, send us your processed images for gallery on info@zwoptical.com.

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Camera= ZWO ASI290MM
Filter= Euro EMC photographic Solar Filter ND3.8 + Continuum
Frames captured= 3000
FPS (avg.)= 81
Shutter= 5.836ms
Gain= 0 (0%)
Frames stacked= 50
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Camera= ZWO ASI174MM
Filter= Euro EMC photographic Solar Filter ND3.8 + Continuum
Frames captured= 3000
FPS (avg.)= 204
Shutter= 3.821ms
Gain= 0 (0%)
Frames stacked= 50
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