Re: [ATM] Advice on Solar scopes/observation

[Dominic-Luc Webb <dlwebb@canit.se>]

On Mon, 19 Jun 2006, Mike Lockwood wrote:
>
> Last week, I wrote:
> > A closed, insulated tube is good.

> With the mention of the Baader solar film, that ...

How I have dealt with solar imaging (not direct visual) is to use a
very strong aperture stop, like between 1 and 4 pinholes and high
magnification. I got the intensity down to the point where this
arrangment could be used with slower films, so I would imagine CCD
plus your choice of filters would work. Sadly, the optics I used was
very poor quality, so what pics I have do great injustice to the
strategy I have chosen.

I am not sure when to choose the filter vs aperture stop strategy, but
the latter should preserve the entire spectrum. One warning on the
pinhole strategy is that the holes need to be very clean, or you can
get very bad light scatter off the edges. I tested a few different
sizes and positions, and this makes a big difference. My system was
a Maksutov and 4 pinholes were situated about 2/3 of the way out from
the center. I do not remember the size of the holes that worked best,
but 2.5 or 3 mm were tried and worked OK.

Dominic

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