Year: 1888

page_text: Date of Application, 29th Mar., 1888
Complete Specification Left, 29th Jan., 1889
Complete Specification Accepted, 2nd Mar., 1889
We Dr. HEINRICH LUDWIG HUGO SCHRÖDER of 5 The Terrace Clapham Common
in the County of Surrey Optician and JOHN STUART of The Hollies Clapham Common
in the County of Surrey Optician do hereby declare the nature of this invention to be
as follows:-
This Invention has for its object the production of a telescope whereby great
differences of magnifying power can be obtained without unduly increasing the length
of the telescope whilst the focal adjustment apparent field and aplanatism are main-
tained throughout the whole range of magnifying power. This is effected by means
of a combination of lenses arranged to admit of altering the positions of the erecting
lense and of the eye-piece lenses so that an immediate alteration of magnifying power
may be obtained with the aforesaid advantages.
The object glass of the telescope may be of the usual achromatized form the rays
passing first through a field or collecting lens from which they converge towards a
lens preferably achromatized. This lens erects the image and also can be traversed
to increase or diminish the magnifying power of the telescope. The erected image
thus produced is magnified by an eye piece containing two lenses which should be of
nearly equal foci the first being a plano-convex lens with its flat side towards the
image and the other a plano-convex lens (preferably achromatized) with its flat side
towards the eye.
For altering the magnifying power two simultaneous movements are required:
Firstly the distance between the field or collecting lens and the erecting lens has to
be altered which may be done by a constantly progressive movement and Secondly
the distance between the eye lenses and the said erecting lens has to be varied for
following and focussing the image produced which may be done by a movement which
is not constantly progressive. These two movements can be obtained by an outer
tube capable of being rotated and having a groove or guide with a regular incline
for the first named movement between the field lens and the erecting lens and also

page_text: a groove or guide with a curve suited for the peculiar movement required between
the erecting lens and the eye lenses. These two grooves contain projections such as
sliding blocks or rollers which are connected by pins to the settings of the lenses to
be moved as aforesaid.
We have described the Telescope as being suited for ordinary ranges for which
Telescopes are used but it may be provided with separate adjustments for the eye
piece or the object glass or for both for use for very short distances if so desired.
Dated this 29th day of March 1888.

page_text: Improvements in Telescopes.
We Dr. HEINRICH LUDWIG HUGO SCHRÖDER of 5 The Terrace Clapham Common
in the County of Surrey Optician and JOHN STUART of The Hollies Clapham Common
in the County of Surrey Optician do hereby declare the nature of this Invention
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
This Invention has for its object the production of a telescope whereby great.
differences of magnifying power can be obtained without unduly increasing the
length of the telescope whilst the focal adjustment apparent field and aplanatism
are maintained throughout the whole range of magnifying power. This is effected
by means of a combination of lenses arranged to admit of altering the positions of
the erecting lens and of the eye-piece lenses so that an immediate alteration of
magnifying power may be obtained with the aforesaid advantages.
We will more particularly describe the invention with reference to the accom-
panying drawings in which Figure 1 is a longitudinal section of a telescope
constructed according to or provided with our invention. Figure 2 is an external
view shewing the slotted or grooved guide tube by which the adjustments are
effected and Figure 3 is a development of the same shewing the form of the grooves
or guides.
Q
The object glass of the telescope may be of the usual achromatized form the rays
passing first through a field or collecting lens A from which they converge towards
a lens B which should be achromatized. This lens erects the image and also can be
traversed to increase or diminish the magnifying power of the telescope. The erected
image thus produced is magnified by an eye piece C containing two lenses preferably
of nearly equal focal length the first being a plano-convex lens with its flat side
towards the image and the other a plano-convex lens (preferably achromatized) with
its flat side towards the eye.
For altering the magnifying power two simultaneous movements are required;
Firstly, the distance between the field or collecting lens A and the erecting lens B
has to be altered which may be done by a constantly progressive movement and
Secondly the distance between the eye lenses C and the said erecting lens B has to
be varied for following and focussing the image produced, which may be done by a
movement which is not constantly progressive. These two movements can be
obtained by an outer tube D capable of being rotated and having a groove or guide d
with a regular incline for the first named movement between the field lens A and the
erecting lens B and also a groove or guide d' with a curve suited for the peculiar
movement required between the erecting lens B and the eye lenses C. These two
grooves contain projections such as sliding blocks or rollers which are connected by
pins to the settings of the lenses to be moved as aforesaid. In the Drawing a block
and a roller are shewn and they are marked respectively b and c the block marked b
being secured by the pins 6' to the setting of the lens B and the roller marked c being
secured by the centre pin to the setting of the lens C.

page_text: We have described the telescope as being suited for ordinary ranges for which
telescopes are used but it may be provided with separate adjustments for the eye
piece or the object glass or for both for use for short distances if so desired. It will
be understood that we do not limit ourselves to the precise details which we have
shown provided that the arrangement be such that the relative adjustment of the
distance between the lenses is obtained substantially as herein before described.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In or for a telescope a combination of field or collecting lens and erecting and
focussing lenses and means for simultaneously adjusting the relative distances between
them by one operation substantially as hereinbefore described.
2. In or for telescopes a tube capable of being rotated and having a groove or
guide with a regular incline for operating to adjust the distance between the field
lens and the erecting lens and a groove or guide for operating to impart the move-
ment required to simultaneously give the variable adjustment between the erecting
lens and the eye lens substantially as heroinbefore described and illustrated in the
accompanying drawings.
3. The arrangement and combination of parts constituting the telescope substantially
as hereinbefore described and illustrated in the accompanying drawings.
DIL
COLL 1
ST1000
J. H. JOHNSON & Co.,
Agents.