New 36mm Optolong SHO filters, but have a dilemma….🤔

[Stuart1971]

So having decided to get a mono QHY268m camera, I have also bought a set of 36mm Optolong unmounted SHO filters, and have an issue, which way round should they be fitted…🤔🤔

now on the Optolong website it states that the most reflective side should go towards the sky…shown here…

https://www.optolong.com/cms/document/detail/id/147.html

but ZWO have stated the complete opposite here on the RVO website…this is what they have said…

WHICH DIRECTION TO INSTALL THE FILTERS IN?

It is a tricky question as we asked various manufacturers and most of these manufacturers think that it doesn't matter, however the manufacturer of ZWO filters advises that the coated side of the filter should face the camera sensor. Well, there is nothing to loose to follow their advice, so lets do it. Now, how to find out which side is the coated? Open the case and remove the filter from its pouch and put it on top of the puch as this is most likely the most dustfree element in your surrounding. Now hold an item, i.e. a pen above the filter, close enough, but make sure that it won't touch the filter. If you see a single reflection as if it was a mirror, that's the coated side; that side should face the camera sensor. If you see a double reflection, that side should face the telescope.

so which one is correct….as the filters are the same….🤔🤔🤔

[tooth_dr]

2 hours ago, Stuart1971 said:

So having decided to get a mono QHY268m camera, I have also bought a set of 36mm Optolong unmounted SHO filters, and have an issue, which way round should they be fitted…🤔🤔

now on the Optolong website it states that the most reflective side should go towards the sky…shown here…

https://www.optolong.com/cms/document/detail/id/147.html

but ZWO have stated the complete opposite here on the RVO website…this is what they have said…

WHICH DIRECTION TO INSTALL THE FILTERS IN?

It is a tricky question as we asked various manufacturers and most of these manufacturers think that it doesn't matter, however the manufacturer of ZWO filters advises that the coated side of the filter should face the camera sensor. Well, there is nothing to loose to follow their advice, so lets do it. Now, how to find out which side is the coated? Open the case and remove the filter from its pouch and put it on top of the puch as this is most likely the most dustfree element in your surrounding. Now hold an item, i.e. a pen above the filter, close enough, but make sure that it won't touch the filter. If you see a single reflection as if it was a mirror, that's the coated side; that side should face the camera sensor. If you see a double reflection, that side should face the telescope.

so which one is correct….as the filters are the same….🤔🤔🤔

Chroma are the same.  I fitted mine as per ZWO guidelines.  However some folks say it doesn’t matter and others say it’s better the other way round. 

[Stuart1971]

1 hour ago, tooth_dr said:

Chroma are the same.  I fitted mine as per ZWO guidelines.  However some folks say it doesn’t matter and others say it’s better the other way round. 

So you fitted with the most reflective surface towards the camera sensor….now that seems wrong to me, and after testing my 2” Optolong L-extreme and L-enhance, they are the other way round, with reflective surface towards the sky…🤔🤔 or at least that’s how they came fitted in the cell…..

[Stuart1971]

Well after receiving the filters and unpacking it’s really obvious which side it the anti reflective side and which is not, as on the one side they are like a mirror, ( anti reflective side)  and the other side is coloured red / purple for the Ha, SII, and blueish for the OIII, this shows a not so good reflection, so according to Optolong the coloured side goes towards the camera sensor, and the more reflective side goes towards the sky…so will try this way round…👍🏻

[Stuart1971]

Just found this, and it seems that LRGB and narrowband filters should be fitted the opposite way round to each other….this is from ZWO…they don’t make it easy….

So with LRGB the reflective side goes towards the sensor, and with Narrowband it goes toward the sky…..

 

[tooth_dr]

I checked my Sii earlier there and it’s definitely got the double reflection towards the camera. 

[Stuart1971]

1 minute ago, tooth_dr said:

I checked my Sii earlier there and it’s definitely got the double reflection towards the camera. 

So according to the above image that is correct….I am going with that too, it seems to make more sense to me to have the strong single reflection side towards the sky…👍🏻