Solar H-alpha imaging – ZWO ASI178MM-cooled (update)

Since the last attempt at solar H-alpha imaging with the Daystar Quark and ZWO ASI178MM-cooled, I have been looking for the opportunity again to image the sun. I had previously encountered Newton rings, suggesting that the camera was not aligned properly with the Daystar Quark. So there were a few things I wanted to try. Sunday 7/2/16 gave me the perfect opportunity, as the skies cleared long enough for me to do some imaging. And the sun had many features to image as well.

Previous setup: Direct coupling of the ZWO ASI178MM-cooled to the Daystar Quark via the FLO Quark-T2 adapter.

Direct coupling of imager to Daystar Quark via T2 adapters
Direct coupling of imager to Daystar Quark via T2 adapters (8mm T2 extension + FLO T2-Quark adapter)


  1. Newton rings were noted in the images, as the direct coupling resulted in the camera being too close to the Daystar Quark and the collimation was slightly off.
  2. Magnification was too high for the seeing from my backyard, so I had to image in 2×2 binning.
  3. High magnification also resulted in a narrower field of view.


  1. I used the Baader 1.25″ nosepiece and Baader T2-1.25″ holder from my Baader Prism to mount the camera. This seems to have kept the imager far enough from the Quark, and also solved the collimation issue (so I don’t need to buy a T2 tilt adapter).

    ZWO ASI178MM-cooled with Baader 1.25" nosepiece mounted to Baader T2-1.25" adjustable eyepiece holder mounted on the Daystar Quark (with Revelation 0.5x FR on end of 1.25" nosepiece)
    ZWO ASI178MM-cooled with Baader 1.25″ nosepiece mounted to Baader T2-1.25″ adjustable eyepiece holder mounted on the Daystar Quark (with Revelation 0.5x FR on end of 1.25″ nosepiece)
  2. I mounted my Revelation 1.25″ 0.5x on the end of the nosepiece to increase the field of view. Now I can image without needing to bin the pixels.
    Revelation 0.5x focal reducer mounted on 1.25" nosepiece of imager
    Revelation 0.5x focal reducer mounted on 1.25″ nosepiece of imager

    As you can see from the images below which were processed with Registax 6, there are no longer any Newton rings. In fact I have not used any flat frames either, as I did not see any dust spots to remove.

    Sunspot AR2494
    Sunspot AR2494
    Another shot of sunspot AR2494
    Another shot of sunspot AR2494
    Area of activity on the sun
    Filaments (dark) and Plage (bright patches) on the sun
    Prominences from 7/2/16
    Prominences from 7/2/16

    What I’ve found out on Sunday:

a) The Revelation 0.5x FR works well for Daystar Quark and the ZWO ASI178MM-cooled. No need to purchase the Baader Solar Telecompressor. The distance with the FR at the end of the nosepiece will give me about 0.5x focal reduction.

b) The collimation issue, Newton rings and dust spots from the filter are resolved by moving the imager further away from the Daystar Quark and mounting with the Baader adapters above.

c) The ZWO ASI178MM-cooled works very well as a solar h-alpha imager.

d) Registax 6 works well with the .avi files which the imager outputs, whereas AutoStakkert!2 will not recognise the .avi files (which need to be converted using PIPP). So I now do stacking in Registax 6 as well as the wavelets to bring out the details. This should reduce my processing time for future solar imaging.

Now I just need to learn to colorize the images using the tools I have available i.e. StarTools and Capture One Pro 8.