Should Optolong filters be installed in a certain orientation? 

source:Optolong popularity:498Release Time:2021-06-26

Should Optolong filters be installed in a certain orientation?  

Recently, we received the queries about Optolong filters whether they maybe installed in a certain orientation like below said:

"I bought 36mm unmounted LRGB & narrow band filters of your company. I have a question. Is there a front and back of the filter when attached to the filter wheel?"

"Should Optolong filters be installed in a certain orientation?"

"Should the male thread side be toward the camera or can it be facing toward the scope?"


We would like to answer the query here. 

The principle is that the main functional membrane faces the light source, and the accessory membrane or AR face CCD or CMOS.

Well, how to identify the AR surface? 


See below graph, you will find the shadow of AR surface with ghosting, obvious silhouette, while another surface of film not.

So "ghosting" surface faces (upper image) the CCD.



The figure on the right faces CCD. 


Hope that can help. We will update the details if any update. Contact us if you have any query!

Welcome always. 


--Optolong Team