ZWO narrowband filter.

dydan

hi~

I have ASI1600MM-C Kit,

found some abnomaly behavior in flatframe of narrowband.

attached samples is flatframe of ZWO narrowband 31mm filter.

the brightness of the central part is abnormal.

i think the cause is a metal part of filter border,

that part reflects a lot of light.

do you have the same experience as me?

Thanks

Sam@ZWO

it looks like flash of your light source

dydan

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Sam@ZWO

the actual filter area is 28mm only

so metal part should not cause this problem

it looks very strange especially the right up corner

al bates

Just maybe a black marker may take care of that metal ring

dydan

Sam wrote:
the actual filter area is 28mm only

so metal part should not cause this problem

it looks very strange especially the right up corner

AL Bates's opinion was right.

I fixed the problem by masking the border.

Thank you AL Bates

It is certain that there is a design problem of the ZWO filter.

1.jpg

2.jpg

3.jpg

dydan

Sam wrote:
the actual filter area is 28mm only

so metal part should not cause this problem

it looks very strange especially the right up corner

Before

before.PNG

After

after.PNG

I don't like to recommend ZWO filter

dydan

AL Bates wrote:
Just maybe a black marker may take care of that metal ring

Thank you AL Bates

Sam@ZWO

we just checked this problem

it is caused by the side of the glass

one way to improve is paint the side of the glass to black

astrodude

I have the same kit and the same issue.

Before I attempt to fix this would can you clarify if it is the edge of the face of the filter that needs painting black (like dydan has done with the rings he made) or is it better to coat the thin edge of the filter itself (the side not the face), or maybe both?. Also would a permanent marker be the best option if its the side that need coating.

Also, (forgive me if this is a daft question) do the filters need to be placed in the EFW a specific side down. I know that some filters have an arrow on them as to which way they should be used but the ZWO filters do not.

al bates

dydan wrote:
Sam wrote:the actual filter area is 28mm only

so metal part should not cause this problem

it looks very strange especially the right up corner

Before

before.PNG

After

after.PNG

I don't like to recommend ZWO filter

Dydan, Nice job cutting the mask rings... wish I had some.

Al Bates

Sam@ZWO

we will paint the outside to black in the future

thanks for your suggtion

moonprince

This is very important found for us, Thanks all ! we will do our best to fix this problem.

al bates

MoonPrince wrote:
This is very important found for us, Thanks all ! we will do our best to fix this problem.

That would be great, Thanks Sam & Moonprince for the rapid reply and for the quick fix.

Al Bates

marke

I am having the same problem , very frustrating has anyone tried a black marker yet ?

I dont want to have replace them.

kcobby

I use a full set o ZWO Narrowband and have never experienced the problems defined in this thread. I capture really nice Flats at ADU 16,000 +/- 500. Maybe the thread examples were over exposing exposure. Would be useful to see the histogram.

starmanmike1

dydan wrote:
Sam wrote:the actual filter area is 28mm only

so metal part should not cause this problem

it looks very strange especially the right up corner

AL Bates's opinion was right.

I fixed the problem by masking the border.

Thank you AL Bates

It is certain that there is a design problem of the ZWO filter.

1.jpg

2.jpg

3.jpg

I’m looking to create a similar ring for my 36mm filters. What are your recommendations for the inner and outer dimensions?

Thanks

Mike

starmanmike1

I’m looking to create a similar ring for my 36mm filters. Any idea what the recommended inner and outer dimensions would be?

Thanks

Mike