Which Camera is better?

 Now you would think that a DSLR attached to the Solar scope would provide a better overall photo. 

There is a standard baseline for telescope resolution which is called Dawes limit which calculates the resolving power of a telescope by splitting binary stars. This is not completely accurate for bright objects such as the sun. As explained, a camera which has a high frame rate can resolve smaller detail.

Nikon D750 is a 24.3m pixel sensor with a 6032 x 4032 resolution with a pixel size of 5.95um

If you use a ZWOAsi178mm camera you will find it is only a 6.4m pixel sensor with a 3096x 2080 resolution with a pixel size of 2.4um

Day Star Solar Scout is 930mm long F/15.5

Resolution = (pixel size/focal length of solar scope)  

so the calculation will be  :

Nikon D750 (5.95/930 )x   206.265 =1.31 arcseconds per pixel

ZWOASi178mm (2.4/930) x 206.265 =0.53 arcseconds per pixel

ZWIASi174mm ( 5.86 /930) x 206.265 = 1.29 arcseconds per pixel

The ZWO cameras have a high frame rate and can cut through the atmospheric distortion by capturing `lucky' breaks ins seeing. Therefore, high frame rate camera systems have greater resolving power than a static imaging camera, such as the Nikon and therefore they should be able to achieve a better resolving power than the Dawes limit.

Therefore the ZWOASi178mm Mono will resolve the best detail.

Image quality

The more magnification will show more detail as it uses more pixels on the target. The increase in focal length helps with the framing, as it magnifies the target area utilising more sensor space and therefore more pixels. As you can see above the 178 has a lot more magnification than the 174mm camera. Cropping would only reduce the resolution.

You could add a teleconverter to the camera and lens to increase the magnification but this will also increase any aberrations of the lens and this will lead to reduced sharpness and contrast. Another problem is that the more glass that is added to an camera system there will always be a loss of quality for astrophotography subjects

By stacking 

Stacking lots of photo together to produce one image is very effective in reducing noise and capturing more detail. The 178mm camera can shoot at 60fps at the highest resolution to 480fps at the lowest resolution

Colour or Mono

For Solar photography a mono camera is better. Colour cameras are less sensitive than mono cameras due to the Bayer Matrix. This means that each pixel is either  Red, Green or Blue filter over it which discards 2/3rds of the light. 

Mono cameras don't require the pixel filter and each pixel can be use all the light gathered to create the image, increasing sensitivity although the photo will be in Black & White but can be coloured later.

Just found out the the scope has been received by RV Optics they are just waiting the the Solarquest head then it will be posted out, cannot wait.