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Old March 21st 18, 12:30 AM posted to sci.astro.research
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Default Solar Flare Imaging for Amateurs

On Tuesday, March 20, 2018 at 12:03:46 PM UTC, Steve Willner wrote:
In article ,
writes:
Amateur solar flare imaging is on my list of
things to do.


If you are talking about white light imaging, aren't such flares
rare?


Incredibly rare. At high altitude observatories in the very clearest
mountain air it is sometimes possible to catch a large H-alpha solar
flare when the sun is hidden behind a mountain. They look pinkish.

Baader planetariums catalogue of solar gear in the late 1990's had
an example photo taken of a big flare with no filters as a sliver
of the photosphere was just coming into view. Obviously this is
quite a dangerous thing to do.

I'd expect glare from atmospheric narrow angle scattering of the
photosphere to prevent you from seeing anything useful at anything
less than 3000m (except during a total solar eclipse). The OP may
be best off eclipse chasing.

The problem becomes how to size
and control a sun cover disk in the telescope.


As the moderator wrote, you don't want to botch this! Two sensible
options are full-aperture filters and eyepiece projection. Using any
kind of focal-plane blocker is risky. If you have to ask for advice,
you shouldn't be doing it.


The cheapest option that will work reliably is a full aperture
energy rejection filter over the objective and a precision narrowband
filter in the convergent beam. A 2A (0.2nm) bandwidth is good enough
to see limb prominences. You might want to consider H-alpha
imaging. That's safer (if your filter is sound), and I believe
H-alpha flares are more common than white light flares.

It is much safer but making your own H-alpha telescope is a challenge
since you cannot afford to take any chances with your eyesight.
Something like this Coronado scope will allow the OP to see solar
prominences with minimal risk.

https://www.bhphotovideo.com/c/produ...Personal.html#!
(other brands are available)

I built my own prominence scope using an early prototype filter
from Coronado.

There must be lots of internet resources on "solar imaging." I
expect you can get better answers in sci.astro.amateur if that group
is still active.


It is still there but it is hardly active these days - overrun with
cranks

Regards,
Martin Brown
(posted via Google groups as my newsreader if playing up)