WA5IYX Solar Images
My first views of sunspot activity came in early 1957 with a 30-power 40-mm
refractor. It was many years later before I became aware that this had been
part of the peak period of historic Solar Cycle 19!
By the 1960's I was using a 3" f/10 Newtonian reflector for observations.
These quickly turned into drawing projection plots of a 5" diameter disk.
(Some of these continued on well into Cycle 21.) A sample (Feb 1968) of
one of these appeared in my article on the VHF propagation effects of Cycle
20 in the December 1974 issue of ham radio magazine.
In the early 1970's I had made attempts to photograph the
solar image projected from the reflector. Not unexpectedly, the
results using simple cameras (e.g., Instamatic) with a fixed-focus and shutter
speed were dismal. I soon attempted to modify an even cheaper camera with
a form of closeup lens. The focus was still at a fixed distance, and
the framing of the image could be haphazard at best.
The obvious solution to this had been known since the mid 70's - an SLR
(single lens reflex) camera. I finally obtained one of these (Pentax
K-1000, 50-mm f/2 lens) in March 1980. The solar image results made a
quantum jump, but the problem of getting a circular image from a camera
that was set off-axis was insurmountable.
By late that year a
Criterion RV-6 (6" f/8 Newtonian) and a
aluminized mylar filter
Solar Skreen, tm) were obtained. What followed
was a lot of experimentation with various eyepieces and image modes
(projection and afocal) to see what gave the best results.
After some professional photograph processing "incidents" a second
Pentax body was added so that both Tri-X and Plus-X film could be used to
produce some redundancy factor (with any overlapping reels being submitted
at different times).
The professional photo shops were never able to render prints of these
images that showed all of the details that were evident on the negatives.
In 1983-85 I did extensive enlarging work at home on selected frames.
(Some of the folk attending past CSVHF Conferences have seen them.)
Even though film images were being taken (creating a large stockpile of undeveloped)
well into the 1990's, time and other constraints precluded my going on with the
protracted "home-photolab" routine.
After a VCR was purchased in 1987 the idea came of transferring those images
to video tape. The lack of a video camera and the image polarity reversal
were the obvious immediate obstacles there! A b&w CCTV camera was obtained
in Apr 1994. It was first used with the telescope and VCR to tape the partial
solar eclipse the next month - but it could not resolve sunspot details on
the disk. In Aug an 8-mm RCA camcorder was added - but my first attempts at
using this on the RV-6 for solar images proved disappointing.
Since then I had found out how to use the 8-mm on the RV-6 for night-time
astronomical objects. This was successfully done with the sun during the
February 1998 partial solar eclipse. What was astounding was just how much
sunspot detail could be seen as well - more than most of those literally
thousands of film exposures had ever given me!
Due to the optical and camcorder system interactions I have
been unable to render a full-disk image as any substantial dark area in the
field causes the center to be "overexposed". I know that more-sophisticated
(aka, costly) camcorders are able to "get around" that problem.
The idea of some sort of frame-grabber immediately came to mind. After
seeing the price range on most of those I recalled the ads that I'd heard
about a device known as Snappy. Checking
out the WWW on it revealed that it had an even more-desirous feature - the
ability to convert photographic negatives into positive images.
This then is the present state of affairs. It will take some experimenting
to get all of its features optimized, but here are some quickly-made samples.
35-mm film: Dec 9, 1981 - what a solar flux of 305
35-mm film: Mar 12, 1989 - huge region that was
responsible for massive aurorae
8-mm video: Mar 25, 1998 - (a rather large 100-k JPEG)
Page last updated October 1, 1999