More galaxies with the Seestar S50

Regulus (Alpha Leonis) is the brightest star in the constellation Leo and the 21st brightest star.  Here is a 10-sec exposure obtained with the Seestar S50 and a cross-star filter:

Regulus.  10-sec exposure with cross-star filter.

 The cross-star filter interferes with tracking and stacking when the Seestar S50 is used in alt-azimuth mode (the physical default).  The diffraction spikes have a fixed orientation with respect to the image sensor, but the star field rotates while the telescope tracks (this is a well-known effect with alt-az telescopes, called "field rotation").  This seems to interfere with the stacking algorithm, so the software rejects subsequent exposures and won't stack beyond the initial image.  This happens mostly when there are bright stars with prominent diffraction spikes.

There is a dim galaxy in the field of view close to Regulus, so the cross-star filter was omitted in order to obtain a long exposure.  Here is an 15-min image obtained without the filter:

Regulus and dwarf galaxy Leo I. 15 min.

 The dwarf galaxy Leo I is a satellite galaxy of our Milky Way galaxy, about 1/50th the size of the Milky way.

 After successfully capturing an image of this dim galaxy, the Seestar was turned to some easier subjects:

M60 (left) and M59 (right). 15 min.

This field shows the galaxies M60  and M59 in the constellation Virgo.   There are multiple additional galaxies visible in this image.

 

M86 (left center) and M84 (right). 21 min.

M86 and M84 are galaxies in the constellation Virgo.  Multiple additional galaxies are visible, too many to specify.

 With previous Seestar images, postprocessing was done by first using the ZWO FitsView app to convert the raw FITS file to PNG format, then importing into Affinity Photo for final (or near final) processing.  This time however, the files were processed in the Seestar app using the AI Denoise feature.  The results are so good that it I will use this method going forward.  

Here are a couple files from the previous post processed with the AI Denoise feature:

NGC 3628, M66, and M65 (the Leo Triplet)

 

M87 (Virgo A)