FIRST REPORT ON EKTAR FILMS

In this final lecture on Ektar, we will discuss gas
hypersensitization, and applications for comet photography, and the
final conclusion on these films.

Hypering Ektar films.

Many astrophotographers may wish to shorten the time required at
the guide scope further by gas hypersensitizing thier film.  Ektar
films respond very well to hypering, using the standard mixture of
92% nitrogen, and 8% hydrogen.  We used a Lumicon Model 300 hyper
kit, however with similar setups you can use the following numbers
as starting points.  It should be noted however that with the Ektar
1000 emulsion, a slightly bluish cast will be introduced into the
background color by the hypering process.

Suggested Gas Hypersensitizing Times for Ektar Films:
Ektar 25.........16 hours, 50 deg C, 1psi, 8x
Ektar 125........12 hours, 50 deg C, 1psi, 6x
Ektar 1000.......10 hours, 50 deg C, 1psi, 2x

Exposure times for Ektar films:

For hypered Ektar 25, 10mins @ f/1.4, 20mins at f/2, 40 mins at
f/2.8, and 80 mins at f/4.

For hypered Ektar 125, 8mins at f/1.4, 16mins at f/2, 32mins at
f/2.8, and 64 mins at f/4.

For Unhypered Ektar 1000, 3mins at f/1.4, 6mins at f/2, 12mins at
f/2.8, 24 mins at f/4.

For Hypered Ektar 1000, 1.5 mins at f/1.4, 3 mins at f/2, 6 mins
at f/2.8, and 12 mins at f/4.

A Comet Film.

As recently as a few weeks back, we did extensive testing of the
Ektar 1000 on a few comets.  Comets Austin, and Cernis-Kiuchi-
Nakamura were photographed with this emulsion unhypered with two
instruments, a 14 inch f/5 newtonian, and a 6 inch f/3.6 schmidt
newtonian.  This film is FAST in short exposures, in fact on both
comets a sky blue color was recorded beautifuly, especially in
Comet CKN.  In a ten minute exposure for example, I shot CKN with
the 14 inch and recorded details right down to sky fog limit.  The
comets rapid motion did not allow exposures from exceeding this
duration or the image would be a blurred streak on the film.  

Comet Austin revealed a broad fan tail with the Meade 622 schmidt
newtonian.  The relatively fine grain of this emulsion also
revealed fine structure in the tail edges in the form of curving
rays.  This is the color film I am recomending for this comet.  I
hope that I can relay this information to you in time for you to
use it on Austin as well as future comets.

Conclusion.

There is an Ektar film for many different aspects of
astrophotography.  One can choose the 25 speed for high resolution
telephoto and schmidt shots or contrasty planetary work.  The 125
speed Ektar has low contrast, but an extended latitude of exposure
making it suitable for detailed lunar and deep sky photography of
bright objects.  And finally, the Ektar 1000 is a new vista for the
astrophotographer with galaxies, open clusters and reflection
nebulae in mind.  Each film is very different, but all have
applications for the amateur astrophotographer.