OIII 6nm filter - Prone to clouds and LED lights?

[souls33k3r]

Hi All,

Thought i should start a new thread and find out an answer to my question.

How prone is a 6nm OIII filter to high thin clouds? Will the clouds show on a stacked image?

Also with the introduction to the new street LED lights, how far does the scope has to be for the OIII to pick up any glare coming from it? Say the LED light is installed in the west and i'm imaging in the south / South West?

The above questions may or may not be related to the resulting image (below) but would love to have your take on it. I only see this in the OIII and not in Ha or SII stacked.

Comparison of Ha and OIII from the same night

Thanks in advance

[angryowl]

You already know my take on this, but just to add some further thoughts.

Those LED streetlights usually have a very different spectrum when compared to Mercury or Sodium. For this reason I’d think that if any stray light would find its way into your imaging train or on the inside of your dew shield, it would show up through the Ha and SII filters too. In fact when looking at some LED spectrum graphs, the Ha and SII lines would probably be more affected than OIII.

Regarding thin clouds I’ll have a look through some of my older images as I know I’ve got some OIII shot through thin cloud. Regardless of filter used, frames with even the tiniest amount of thin clouds in them are easily discernible from clean ones.  When going through your subs the other day, I’ve not seen much variation in them visually or their SNR values, they all looked very much alike.

Of course you know my setup and although my Baader F2 High Speed narrowband filter specs don’t mention it, they’re probably around the 12nm mark so no direct experience with 6nm, but I should imagine you’d still be able to easily spot an exposure that was shot through thin cloud and a clean one even with your filters and at your F ratio.

[souls33k3r]

1 hour ago, angryowl said:

You already know my take on this, but just to add some further thoughts.

Those LED streetlights usually have a very different spectrum when compared to Mercury or Sodium. For this reason I’d think that if any stray light would find its way into your imaging train or on the inside of your dew shield, it would show up through the Ha and SII filters too. In fact when looking at some LED spectrum graphs, the Ha and SII lines would probably be more affected than OIII.

Regarding thin clouds I’ll have a look through some of my older images as I know I’ve got some OIII shot through thin cloud. Regardless of filter used, frames with even the tiniest amount of thin clouds in them are easily discernible from clean ones.  When going through your subs the other day, I’ve not seen much variation in them visually or their SNR values, they all looked very much alike.

Of course you know my setup and although my Baader F2 High Speed narrowband filter specs don’t mention it, they’re probably around the 12nm mark so no direct experience with 6nm, but I should imagine you’d still be able to easily spot an exposure that was shot through thin cloud and a clean one even with your filters and at your F ratio.

Appreciate your further analysis on this matey.

I really didn't think the LED could be the cause but still worth a mention. As you know i image from the same location and have previously used the OIII filter and have never seen such grid like pattern so did wonder what else could it be.

With regards to the thin clouds, i did notice (not sure if you did too) that the OIII frames were slightly on the brighter side of things. Don't you think?

I'll see if i can somehow get the GIF of the entire frames.

[souls33k3r]

Just updated my original thread so i can draw this thread to a close.