UV IR L Pro?

[Simon Pepper]

Hi all,

Hopefully a real quick one here. Am I going to see any improvements in my image quality if I shoot with a UV IR cut filter such as the Optolong L Pro from a bortle 4/5 or should I not bother? As light pollution is not too bad wondering what others think? This is on a OSC and for broadband targets. 

 

Thanks

Edited May 26, 2021 by Simon Pepper
Updated

[david_taurus83]

Bortle 4 is quite dark so if you don't have to deal with streetlights directly or nearby skyglow, I'd only use a normal IR/UV cut clear filter. If you use a light pollution filter you will need to expose for longer. With my 6D, clip in L Pro filter and Samyang 135 at f4 I can take a 2 or 3 minute exposure without over doing it. Pointing straight up with no moon about, I can do 5 minutes. The majority of the exposure is taken up by LP which is removed later in software. If I was to use the L Pro at a dark site though I would have to expose for significantly longer to get the histogram off the left side. Not enough exposure and it's difficult to get a less noisy background. 

[Simon Pepper]

1 hour ago, david_taurus83 said:

Bortle 4 is quite dark so if you don't have to deal with streetlights directly or nearby skyglow, I'd only use a normal IR/UV cut clear filter. If you use a light pollution filter you will need to expose for longer. With my 6D, clip in L Pro filter and Samyang 135 at f4 I can take a 2 or 3 minute exposure without over doing it. Pointing straight up with no moon about, I can do 5 minutes. The majority of the exposure is taken up by LP which is removed later in software. If I was to use the L Pro at a dark site though I would have to expose for significantly longer to get the histogram off the left side. Not enough exposure and it's difficult to get a less noisy background. 

Hi David 

when you say normal uv ir can you provide any links to some recommendations?

thanks

[The Lazy Astronomer]

11 minutes ago, Simon Pepper said:

Hi David 

when you say normal uv ir can you provide any links to some recommendations?

thanks

A selection of 'normal' UV/IR cut filters can be found here: https://www.firstlightoptics.com/uv-ir-filters.html

With OSC, you'd really only want to use one if you're finding you get bloated stars from unfocused uv/ir. Otherwise I don't think you'd see any difference to be honest. 

[Simon Pepper]

5 minutes ago, The Lazy Astronomer said:

A selection of 'normal' UV/IR cut filters can be found here: https://www.firstlightoptics.com/uv-ir-filters.html

With OSC, you'd really only want to use one if you're finding you get bloated stars from unfocused uv/ir. Otherwise I don't think you'd see any difference to be honest. 

There were two reason why I was considering it... Firstly using the l extreme filter I have awful halos around the brighter bigger stars and I have been googling ways to fix in post. One user over on CN says they use a UV IR cut to expose a few minute long subs so they have a luminance picture of essentially just the stars then using pixel math in PI and a few other tweaks merge them together. Secondly for broadband targets as mentioned to provide more contrast, but was unsure if that was worth it being in bortle 4.  Thanks 

[david_taurus83]

Most pictures I've seen with the L-Extreme show halos on bright stars. What camera will you be using? 

[Simon Pepper]

10 hours ago, david_taurus83 said:

Most pictures I've seen with the L-Extreme show halos on bright stars. What camera will you be using? 

Redcat asi294 mc pro. I am thinking of trying this uv ir filter trick but obviously don’t want to spend money on something that may not work. I think I will just have to bite the bullet and try it...

[david_taurus83]

Will a 1.25" filter cover the sensor if you use the adapter to fit inside the 11mm spacer? Cheap ZWO IR/UV filter is only about £25 or so.

[The Lazy Astronomer]

I use 1.25" filters with an asi294mm (same sensor size) @ F5.5 and they work fine. Some vignetting, but easily corrected with flats. Just need to get the filter as close to the sensor as possible.