Ha solar imaging with OSC cameras

[Dave S]

This should be a simple one for all you narrow band boffs.

I'm currently in the process of acquiring a gpcam2 colour camera.

It occurs to me that with the increased sensitivity to IR over an unmodded DSLR I would have thought that as the sun is a lot brighter than an emission nebula then despite the reduction in light transmission due to the Bayer matrix i would have thought that solar prominences would be possible to capture using a Ha filter in conjunction with the baader solar film I use.

Anyone had any experience of this.

Dave...

[Zakalwe]

Not in a million years.

The bandpass on a H-a filter is an order of magnitude (or two) too wide to capture chromosphere details. If all it took to record the prominences was a bit of solar film and a H-a filter then why would anyone be spending thousands on an Etalon? Its nothing to do with the amount of light coming through and everything to do with the type of light. A proper solarscope uses a special filter called an Etalon, allied with energy-rejection and blocking filters to eliminate all other frequencies except for the light emitted in the hydrogen-alpha wavelength.

You can use a colour camera with a proper solarscope, but it's less than an ideal solution. The camera will only record information in the red pixels (1 in every 4) so you lose resolution there. Plus the green and blue pixels do nothing other than introduce noise into the image.

[Dave S]

Ta. Thought it wouldn't be that simple. Another thought occurs. Solar film probably blocks as much of the nasty retina destroying IR as it can.

Dave...

 

[michael.h.f.wilkinson]

Just to put things into perspective: a really narrow-band H-alpha filter for DSO work may have a bandwidth of 3nm. My Solar Spectrum etalon is rated at 0.3 Å, or 100 times narrower.

[Zakalwe]

44 minutes ago, michael.h.f.wilkinson said:

Just to put things into perspective: a really narrow-band H-alpha filter for DSO work may have a bandwidth of 3nm. My Solar Spectrum etalon is rated at 0.3 Å, or 100 times narrower.

Two orders of magnitude difference.

[michael.h.f.wilkinson]

13 hours ago, Zakalwe said:

Two orders of magnitude difference.

And three orders when you compare it to the more affordable 35nm bandwidth DSO H-alpha filters