The Dutch Observatory

July 8, 2019 on 9:47 am | In Sun | Comments Off

Today I made some comparative images using the ZWO ASI174MM and ASI120MM-S cameras.  The main difference between the two cameras is the chip size and the pixel size.  I made images of two different targets, AR2744 and the filaments near the Western limb in different configurations using my SolarMax 40 Ha scope, while processed the same in Photoshop.  The first two show closeups of the targets using the ASI174MM in combination with a 3x barlow.  The next two show the ASI120MM-S in direct focus.  All the previous images did not show signs of Newton rings.

The following images were stacked using a separate dark frame each for the two sets in AS2.  The next two images show the ASI120MM-S with a 2x barlow cell of a Meade series 140 barlow screwed directly onto the nose piece of the camera giving approx. 1.6 magnification.  I notice faint very tight Newton rings especially in the dark area to the right of the Sun.  This has been processed out in Photoshop.  The last set is taken with the ASI120MM-S with a 2x Celestron barlow and shows heavy banding.  It should be noted that all images with the ASI120MM-S were taken with a tilter installed at maximum tilt.  The ASI174MM was not tilted.