DSLR + T Ring / Adaptor + Barlow + Coronado Solarmax 60

[Kenny]

Any help / advice please...

The T Ring / Adaptor for my Canon 450D arrived this morning. Rather than wait for darkness to approach, I decided to try it out with the Coronado expecting to get a full solar image in frame (unlike the NexImage where I need to mosaic it).

Good News: Easily get full solar image in frame with x2 adaptor, slightly less than full image with x3 adaptor.

Bad News: Disappointing results!

• Looking through the viewfinder is fine. I can adapt the ISO and exposure to get an image comparable to what I can see through the Televue 17.5mm eyepiece.
• However, looking at the LiveView image, or using the Canon EOS Utility with my laptop (made focusing much easier), the image of the Sun is invisible unless I significantly lengthen the exposure. But when I then take a photo using these settings the image is resulting image is massively over-exposed.
• I am getting a darker band of "vignetting" diagonally across the image. I've tried adjusting the placement of the Sun to avoid but but can't find a 'sweet spot'.
• Also, the image of the sun is very grainy with not much detail. It actually looks like it's slightly out of focus (but isn't). Is that the quality I should expect? Do I need to take fully frame video and then stack that to get back to a more detailed image? I tried stacking half a dozen stills but there was no improvement in the image quality.

A few example images below:

1/250th sec, ISO-1600 (Sun is invisible in LiveView)


1/320th sec, ISO-1600 (Sun is invisible in LiveView)


1/50th sec, ISO-1600 (Sun is visible in LiveView)

p.s. lovely prominence showing on this one