Solar Flare Imaging for Amateurs

[e***@gmail.com]

Amateur solar flare imaging is on my list of
things to do. The problem becomes how to size
and control a sun cover disk in the telescope.
This is the "blanking" disk in the telescope.

My solution is to cover the sun with an x by y
rectangular card. A control screw will move the
card edge toward and away from the target peak
point on the sun. One point of the sun's corona
exposed.

Although this causes a rather limited view of
flares, it fully allows flares to be imaged.

My telescope is having its Magnesium Oxide
film removed and replaced. The project is a
ball of mine. It will be a manual control.

[John Heath]

Post by e***@gmail.com
Amateur solar flare imaging is on my list of
things to do. The problem becomes how to size
and control a sun cover disk in the telescope.
This is the "blanking" disk in the telescope.
=20
My solution is to cover the sun with an x by y
rectangular card. A control screw will move the
card edge toward and away from the target peak=20
point on the sun. One point of the sun's corona
exposed.
=20
Although this causes a rather limited view of
flares, it fully allows flares to be imaged.
=20
My telescope is having its Magnesium Oxide
film removed and replaced. The project is a
ball of mine. It will be a manual control.

I was thinking home brew pin hole camera. But in this case the pin
hole is to bring the amount of light within the dynamic range of a
computer security cam that has zoom , right left up down pan
abilities. Now you can look at the sun all day from the comfort of
your computer desk. Even take a snap shot now and then if you see
something interesting.

[[Mod. note --
A big concern in the design of any solar telescope is that if you
focus all (or even a substantial fraction) of the sunlight incident
on a reasonable aperature into a small focal plane, you get *very*
intense light and heat. It's essential to reject this safely & reliably.
And any mechanical or software failure in the blocking mechanism could
expose your detector (whether some sort of camera, or a human eye) to
dangerous light levels. People have suffered permanent eye damage when
a solar filter cracked or came loose from a solar-telescope entrance
aperature.

In contrast, a pinhole camera should be safe enough *if* the pinhole
is mechanically robust (i.e., you can be certain it won't fall out of
position).
-- jt]]

[Steve Willner]

Post by e***@gmail.com
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?

Post by e***@gmail.com
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.

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.

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.

[|***@nezumi.demon.co.uk]

Post by Steve Willner

Post by e***@gmail.com
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.

Post by Steve Willner

Post by e***@gmail.com
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/product/324412-REG/Coronado_PST_PST_H_Alpha_Personal.html#!
(other brands are available)

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

Post by Steve Willner
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)

[e***@gmail.com]

Thanks for the reference to the Coronado telescope..

My first steps are to get images. I will begin with
white light and design/buy a remote mounting system. I want
to put a color monitor by my TV set and take video or still images.

The Coronado telescope referenced is obviously the best way
to start imaging a prominence.

I will never be looking thru an eyepiece so cooking the
camera is my only variable.

Scientifically there is little I can add using my images.
Testing sunlight for the existence of correlated light
is possible with a simple interference optics table. But
that is a job for a real scientist. Designing the sensor
to image, in 2D, correlated light is something I can help with
if anybody needs my help to do this. I am a mechanical kind of guy.

I am an artist, btw. I consider a color filtration of
sunlight to be a real artistic creation. I would design
a scheme of filtration using a set of N filters.