Filter Blemish

[OneCosmos (Chris)]

Hi,


I have recently acquired a full set of Chroma 50mm unmounted filters to use with my ASI6200.


All looks good except for the luminance filter which has, what I think is a significant blemish.


A question for the mono imagers but perhaps anyone imaging is how deleterious do you think it will be to the RAW data? Should I just bite the bullet and buy a replacement?


Thanks.

[Startrek (Martin)]

3 reasons why I’d replace the luminance filter -

1. Luminance provides all your detail

2. Your ZWO6200 is a super sensitive , low noise high performance camera and deserves a filter in tip top condition

3. Chroma says it all

Cheers
Martin

[OneCosmos (Chris)]

Originally Posted by Startrek

3 reasons why I’d replace the luminance filter -

1. Luminance provides all your detail

2. Your ZWO6200 is a super sensitive , low noise high performance camera and deserves a filter in tip top condition

3. Chroma says it all

Cheers
Martin

Thanks - I am going to replace it.

[OneCosmos (Chris)]

Whilst it is a significant blemish and I have now ordered a brand new Chroma luminance filter I did get a chance last night to take a quick sub using the filter and tbh it is amazing that I can't actually see any issues the blemish caused.

I had a litany of problems last night as it is the first time I've set up an imaging rig in 7 years. I had dust off half-remembered polar alignment routines, working with NINA I've never used - took me a while to even see how to get autofocus working and to cap it all PHD2 just kept closing of its own accord so I couldn't guide at all. To cap it all, my new counterweight hasn't arrived yet s the scope is horribly unbalanced in RA.

What I've attached though is not an image per se, just a screen snip of a single luminance frame of 30 seconds. There is very slight trail but in essence I can't see any deleterious manifestation of the blemish.


The first image is cropped but I've also included the uncropped one.

Taken with the ASI6200 full frame camera on the Avalon M-Uno with the blemished 50mm unmounted Chroma Luminance filter.


For good measure I also included the same through the Chroma 3nm h-alpha filter. Tbh the h-alpha one doesn't look quite focused, but I was also having problems with my dew straps which are connected to the Eagle but controlled via the ECCO. What I hadn't realised is you have to calibrate the temp sensors first and I didn't. I reckon the h-alpha image may be through some amount of dew.

[PRejto (Peter)]

Maybe take a flat through the L filter.

Can you tell what the blemish is? Is it "just" the coating on the filter?

Curious now...

Peter