Astrophotography – solar (Sun)


I took down the RAG Solargraph that had been in place on the front wall of my house all last year and finally got around to scanning it in.

It was scanned at 1200 DPI, the highest resolution available on my printer/scanner, then rotated and flipped.  It took a while for me to realise that the flip was necessary in order to work out what I was looking at.  Seems obvious, in hindsight!  Then I created a negative image (thereby making the negtive positive) and cropped the edge beyond the south-west as it contained nothing but the shadow of the house next door.

Here is the result.  Apart from the above, the image is not doctored in any way.  Playing around with colours and sharpness didn’t seem to add anything useful, so I’ve stayed with the original settings.  You can just make out the image of my campervan, slightly west of south.  I’ve a better view to the east, but couldn’t quite catch the sunrise itself.  Silhouettes of trees and houses are vsisble along the skyline.  The white dots are street lights and ‘security’ lights that couldn’t be avoided (short of covering the camera up over night, every night).

It was an interesting experiment and the result is actually better than I expected, so I’m quite pleased with this.

Derry North

Solar disc in Calcium H 25/6/2020

Hot on the heels of my Daystar Hydrogen Alpha Quark-filtered image in my previous post, I have now taken some images using my Daystar Calcium-H filter on the same scope and with same camera.

…Well I am on a roll – why not?

I have taken images using variety of settings – still need to decide which is best – so here are two images at opposite extremes of settings on the Calcium-H Quark.


My best ever image of solar surface – yippee!

I have managed to get flat frame and dark frame to work in FireCapture – turned out to be really ease to get flat frame after all – just completely defocus the image of the solar disc with Quark still in, slightly adjust image so not at edge sun but in middle (when defocused adjust using mount hand control until reasonably bright across whole image no darkening near one edge), move exposure length slider (NOT gamma) until top histogram 1/3 from top edge, click on flat frame box and it will take flat frame. Dark frame, simply cover scope and press dark frame click box. Now flat and darks are automatically subtracted constantly – nothing else needs to be done……and Newtons rings are magically gone. Wow!

So here is my best ever image of the sun from today – notice the two dust bunnies – sorry about those!

Also (thanks Damian for the advice), I have tested my Quark H at different settings – and on my Quark best setting is (as Damian suggested) -5. No wonder I couldn’t get good photos in past when I was trying +3, following advice I’d received from another source that best setting on Quarks was 0-+3.

  • Sky Watcher Equinox 100mm OTA
  • HEQ5 Pro Mount.
  • ZWO ASI 174MM USB 3.0 Camera


Surface of sun 24/6/2020

Sky Watcher Equinox Pro 100mm OTA

  • HEQ5 Pro mount
  • ZWO ASI 174MM camera
  • Best 274 frames of 808 frames taken over 17 secs (FireCapture).
  • ASK3
  • ImPPG
  • Photoshop

Got dark frame to work on FireCapture but not flats so Newtonian rings (altering dark and white bands) still present – also some dust bunnies!


My picture turned out as below….ImPPG allowed me to move the black point to the lowest brightness pixel present – sprad out data BUT also left the impression that there are black flames on the sun’s surface(!) – or, as my daughter Hannah suggested, makes it look like the sun has blackheads (acne vugaris).

I have therefore inverted the image in Photoshop CS6 below. Which image do you prefer?