ODK Halos and Ghosting

Frequently we are asked to look at customers images, some of which show ghosting or halos around stars. Their query is that they think the telescope’s lens corrector system is creating these abnormalities. so, we asked Harrie Rutten, one of the World’s leading designers of optical systems to take a look at an ODK optical design. One point to consider here is that all the ODK series of ‘scopes utilise exactly the same corrector system, they are all based on same primary/secondary speeds and result in an f6.8 focal ratio. so what ever relates to one, relates to all.

Here is Harrie’s email which arrived today and analyses in great detail the ghosting in an ODK telescope: …


I did full ghost analyses of the ODK 16. I have to give you very BIG compliments. This is one of the best ghost free designs I have seen ever. I calculated hundreds! Incredible good. The brightness of the ghost is more than 20 magnitudes fainter as the source! This is professional quality! If you have any questions about the analyses, please ask! Attached the report. Very Best Regards and many congratulations with this beautiful design which you reached without ghosting analyses… incredible!

If anyone wishes to see all the number crunching and results from his analysis, please email and we will send them out to you. There just isn’t room here for all the PDF files.