Newton-lens photocorrector

supplied by Jiøí Drbohlav

diameter 135 mm
speed 1:4,2
focus 550 mm
tube diameter 160 mm
tube length 510 mm
The camera is fixed with bayonet to the photocorrector.
It is possible to turn the camera to the desired position.

Comparison star sizes in the centre and on the edge of the field:
Pictures of the globular cluster M13 in Hercules. On the first picture the cluster is in the centre of the field; the star image size is 3x3 pixels. On the second picture the cluster is in the edge of the field; star images have a comparable size to the previous picture. Both of the pictures have 30  seconds exposure in order to minimize errors (seeing, driver).

M13 in the center of the field M13 in the center of the field M13 on the edge of the field M13 on the edge of the field
M13 in the center - the whole field
preview - click to get the whole picture (1 MB!)
M13 in the center - cropped
real scale of the picture
M13 on the edge - the whole field
preview - click to get the whole picture (1 MB!)
M13 on the edge - cropped
real scale of the picture

Comparison star images using and without using of the photocorrector:
M13 in the edge of the field. The first picture is made with the photocorrector; the second without them. The coma-deformation of the star images is distinctly visible.

M13 with the corrector M13 without the corrector
with the corrector without the corrector

Another photos:

X+h Per NGC 6340   
Double cluster X+h Per
preview - click to get the whole picture
Cluster NGC 6940
preview - click to get the whole picture
  
All the photos are made by the camera Canon EOS 300D. The camera was set to the sensitivity of 800 ISO. The photos are not corrected.

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