Customer reviews
it works, but...
Review by JanH on 05.06.2015 18:50:44( 3 / 5 )
This extension ring gives additional optical length of 23 to about 30mm. Title says 31mm, but threads are a little bit loose so full extension is recommended only for smaller loads.
External diameter is 53mm so it doesn't fit INSIDE 2" focuser (with about 50.8 clear aperture...). I hoped to use it between RRC1 corrector and OAG to reach the focus and maintain distance from focal plane at the same time.
The only 2" extension ring I know that can be suspended into 2" focuser is http://www.astroshop.eu/extension-tubes/ts-optics-2-extension-tube-with-filter-thread-at-both-ends-15mm-optical-path/p,43682 and other lengths from same line respectively.
With Newtonian telescopes It's necessary to get coma corrector as deep as possible or to move primary mirror forward in order to reach focus with camera mounted via ordinary T2 adapter.
Can be broken into 3 parts: male-to-male M48 thread (23mm long with 2.8mm thick collar which is 4.6mm away from one end); M48 female ring 14.8mm long (uninterrupted); 5.3mm thick tightening ring (female M48).
Yes, I wound recommend this product but only for certain applications. An option might be T2 variable extension ring when smaller aperture is OK - fits into the focuser.
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