Scopestuff Anteres .5x Focal Reducer

E2Pilot — Sun, 05 Feb 2006 18:07:00 GMT

Thought I would post the results of a test I did for ScopeStuff this week comparing their new Anteres .5 Focal reducer to my ATIK focal reducer. Both of these reducers are the 1.25" nose piece types that screw directly onto your 1.25" eyepiece or the nose of your camera. Both offer .4 to .6 reductions.

The point of my test was to compare them against each other and in my case, to see how they worked with the DSI cameras and more specifically, the larger CCD chip on the DSI-Pro II.

Setup:
For this test, I used each reducer on the same target thru my LX90 with my DSI-Pro II. The DSI had my ATIK filter wheel on it and the Meade IR filter was selected. Because of the high sky glow in this area, I also used my IDAS LPS filter on the front of each reducer while imaging.

Imaging Process:
For each set of images, I ensured that one star (my reference) was located in the same spot on the chip (since I had to remove the camera to change reducers). I also setup guiding via another DSI to limit drift, wind effects, etc. Each set of image consisted of 40 exposure of 30 seconds each of NGC2903 and the surrounding area.
Post Processing:
From each set, I selected the best 20 images and stacked them in Envisage. I then imported them into PhotoShop where level adjustments were performed to try to balance each image. I also applied a false flat to each (made from the original images) to try to reduce some of the evident vignetting. No other adjustments were made including any changes to the stars, contrast, etc. I did make some annotations on the images and save as JPEG (no compression).

Test Images:

Test Results:

FOV – The ATIK has a slightly wider FOV then the Anteres. I measured this at a little less then 5% but both are in the same ball park
Vingetting – the Anteres was much better here. Stars near the outer 20% or so of the ATIK show definite flaring. Some of these stars were outside the FOV of the Anteres, but other could be compared directly those were better then in the ATIK image.
Contrast – The Antares appears to have better contrast then the ATIK. While this is a little more subjective in nature, the vignetting with the ATIK contributed directly to this and shows as a much brighter core and dark corners. The Antares was a much flatter field allowing for greater contrast at the center of the image.

Final Opinions:
I have used the ATIK reducer for a couple of years and have not had any issues with it. However, this has always been with cameras having smaller chips then the new DSI-Pro II. This increase in size made quite a difference in the capabilities of this reducer. The Antares, on the other hand, handled the larger chip much better with greater contrast and far less vignetting. While they are both quality reducers and even considering the slightly larger FOV of the ATIK, I would have to give this test to the new Antares overall. It appears to work very well with the new cameras and is very capable at a good price.

Eyepiece, Barlow, Reducer Reviews

Scopestuff Anteres .5x Focal Reducer