What is the best broadband filter in 2023 for OSC cameras ?

[Northernlight]

Hi all, I have a osc camera and I’m looking for recommendations for the best broadband filter for osc cameras in 2023. Im only interested in broadband targets such as galaxies & comets and maybe some reflection nebula.

only interested in broadband filter recommendations, not interested in narrowband filters recommendations as I already have the optolong ultimate.

 Many thanks in advance,

Rich.

 

[Astroscot2]

Rich, how bad is your LP?

[Northernlight]

Bortle 6-7

Edited July 16, 2023 by Northernlight

[Adam J]

48 minutes ago, Northernlight said:

Hi all, I have a osc camera and I’m looking for recommendations for the best broadband filter for osc cameras in 2023. Im only interested in broadband targets such as galaxies & comets and maybe some reflection nebula.

only interested in broadband filter recommendations, not interested in narrowband filters recommendations as I already have the optolong ultimate.

 Many thanks in advance,

Rich.

 

I would still say a UV/IR cut even in 6-7.

Adam

[Northernlight]

I do have a uv/ir cut filter which I can try, but I see a lot of people going for the likes of the Optolong L-Pro and wondered how much of a difference it would make over a standard uv/ir cut filter.

Edited July 16, 2023 by Northernlight

[ONIKKINEN]

L-Pro vs UV/IR would probably depend on the target. For the Pleiades an L-Pro probably has an edge because most of the nebulosity is blue which the L-Pro passes. However the background dusty nebulosity is more broadband than just blue so you get less of that so its not without compromise.

For galaxies, at least in theory, a UV/IR filter is the best since it blocks the least amount of light.

Another thing to consider is the type of light pollution you have. If you have LED lights then there is no cure other than traveling since those are very broad spectrum and no filter can block that without also blocking all the galaxy light.

Stick with the UV/IR for now. Bortle 6 is not too bad yet and you can go for any target you like, provided you get a long enough integration.

Edited July 17, 2023 by ONIKKINEN

[tomato]

I would go with the UV/IR cut filter from your location for imaging galaxies and let your processing software deal with any LP gradients.

[bomberbaz]

Astronomik filters, the L range (1-3), I use an L2 filter, I know @AstroNebulee uses an L3. 

FWIW I am very happy with my L2, there are no star halos and it provides a clean image.

However I don't have the L3 to run comparisons and if astronebulee comes along, he will hopefully share his thoughts on the L3!

[AstroNebulee]

55 minutes ago, bomberbaz said:

Astronomik filters, the L range (1-3), I use an L2 filter, I know @AstroNebulee uses an L3. 

FWIW I am very happy with my L2, there are no star halos and it provides a clean image.

However I don't have the L3 to run comparisons and if astronebulee comes along, he will hopefully share his thoughts on the L3!

I use a zwo asi294mc pro and as Steve says I use the Astronomik L3 filter and it has revolutionised my astrophotography images.

Due to my Skywatcher 72ed producing quite bloated stars and large blue halos this filter works so well for me. It tightens up the stars often showing groups that would of otherwise been merged together. I was advised that the L3 was best for my scope and I'd agree.

I'm in bortle 3 skies and the L3 filter has outperformed the svbony and zwo uv/ir filters that I tried first. 

Lee 

Edited July 17, 2023 by AstroNebulee

[TiffsAndAstro]

On 17/07/2023 at 20:27, tomato said:

I would go with the UV/IR cut filter from your location for imaging galaxies and let your processing software deal with any LP gradients.

Sorry for asking, but why a UV/ir cut filter ? Why not just a light pollution filter? Thinking of getting a osc and unsure which filter I should get

[TiffsAndAstro]

On 17/07/2023 at 21:40, AstroNebulee said:

I use a zwo asi294mc pro and as Steve says I use the Astronomik L3 filter and it has revolutionised my astrophotography images.

Due to my Skywatcher 72ed producing quite bloated stars and large blue halos this filter works so well for me. It tightens up the stars often showing groups that would of otherwise been merged together. I was advised that the L3 was best for my scope and I'd agree.

I'm in bortle 3 skies and the L3 filter has outperformed the svbony and zwo uv/ir filters that I tried first. 

Lee 

I'm about to get a zwo 585mc (and 72ed)  and am clueless about what filter to get. Would Astronomik L3 filter screw in so I wouldn't need a drawer (seen videos saying back focus is tight)

[tomato]

36 minutes ago, TiffsAndAstro said:

Sorry for asking, but why a UV/ir cut filter ? Why not just a light pollution filter? Thinking of getting a osc and unsure which filter I should get

Galaxies, or at least a lot of them, are faint objects so you need as many photons from the source as possible hitting your sensor, and a UV/IR filter will let more light through. It's only my opinion, but I find modern software light pollution removal tools (I use the one in Astro Pixel Processor) do a fantastic job on removing even severe LP gradients.

[TiffsAndAstro]

42 minutes ago, tomato said:

Galaxies, or at least a lot of them, are faint objects so you need as many photons from the source as possible hitting your sensor, and a UV/IR filter will let more light through. It's only my opinion, but I find modern software light pollution removal tools (I use the one in Astro Pixel Processor) do a fantastic job on removing even severe LP gradients.

Cheers for this. Software does seem ok at removing it.

Why ir cut though? Wouldn't I want ir with a osc ? 

[ONIKKINEN]

1 hour ago, TiffsAndAstro said:

Cheers for this. Software does seem ok at removing it.

Why ir cut though? Wouldn't I want ir with a osc ? 

Passing IR makes proper colour calibration impossible, because more than the visible spectrum was passed. It will also dilute colours in general, because at around 800nm wavelength and above the bayer matrix of most cameras turns fully transparent, meaning the data is monochromatic and all colour information at this wavelength and beyond is lost.

There is also the issue of optics. If using a refracting telescope, then passing IR will make stars enormous blobs due to chromatic aberration, because the lenses are not designed to operate on infrared wavelengths. Even with a reflecting telescope there can be issues, such as internal reflections within a coma corrector that cause stars to balloon in size, especially redder stars that are brighter in IR. I have experimented with imaging sans UV/IR cut filter with my newtonian but there were other issues too, such as the flocking of my tube being insufficient at reducing infrared reflections, and the mirror coatings being slightly transparent which caused stray light to pass through the back of the mirror (flats were impossible - complete waste of time).

So i think to be safe you really should use the UV/IR cut filter.

[TiffsAndAstro]

3 minutes ago, ONIKKINEN said:

Passing IR makes proper colour calibration impossible, because more than the visible spectrum was passed. It will also dilute colours in general, because at around 800nm wavelength and above the bayer matrix of most cameras turns fully transparent, meaning the data is monochromatic and all colour information at this wavelength and beyond is lost.

There is also the issue of optics. If using a refracting telescope, then passing IR will make stars enormous blobs due to chromatic aberration, because the lenses are not designed to operate on infrared wavelengths. Even with a reflecting telescope there can be issues, such as internal reflections within a coma corrector that cause stars to balloon in size, especially redder stars that are brighter in IR. I have experimented with imaging sans UV/IR cut filter with my newtonian but there were other issues too, such as the flocking of my tube being insufficient at reducing infrared reflections, and the mirror coatings being slightly transparent which caused stray light to pass through the back of the mirror (flats were impossible - complete waste of time).

So i think to be safe you really should use the UV/IR cut filter.

wow some fantastic info here i had no idea about ty. one of the reasons i'd like to ditch my dslr and go over to a osc camera is to capture some Ha but this makes it sound like i would need a mono camera and multiple filters which i don't want to do for a long time. 

should just stick to my dslr if im going to filter out ir spectrum?

[ONIKKINEN]

18 minutes ago, TiffsAndAstro said:

wow some fantastic info here i had no idea about ty. one of the reasons i'd like to ditch my dslr and go over to a osc camera is to capture some Ha but this makes it sound like i would need a mono camera and multiple filters which i don't want to do for a long time. 

should just stick to my dslr if im going to filter out ir spectrum?

OSC dedicated astronomy cameras will still be significantly better in every aspect, so definitely worth it. For example Canon DSLRs have a red light blocking filter that passes only around 1/4th of Ha compared to dedicated astronomy cameras (or modded DSLRs). So you would be getting Ha at 4x speed compared to DSLRs. Mono with an Ha filter will be around 4 times faster than OSC, because every pixel will be capturing Ha as opposed to every 4th pixel of an OSC camera. So mono + Ha filter will be around 16x the speed of a DSLR and OSC will be around 4x the speed of a DSLR (ignoring other camera specs, in reality the difference is actually a bit larger because DSLRs are more noisy).

UV/IR cut filters for astronomy purposes fully pass Ha so you lose none of it when using one, so its not the same kind of filter found on DSLRs. In short: definitely worth it to upgrade from a DSLR.

Edited April 1 by ONIKKINEN
small typo

[900SL]

Cooled OSC has significant improvements over a DSLR. Improved Ha signal for starters, much less thermal noise, and ability to match calibration frames to temperature and gain. 

L2 filter is good for an APO unless you have poor colour correction. The L3 is the most aggressive. Check whether the camera has a UV/IR filter built into the sensor cover glass, some do, some don't.

I have an L Pro and never use it. It cuts out sections of the spectrum including broadband signal. I just use the L2 on OSC broadband targets, and take care not to overexpose 

[TiffsAndAstro]

9 minutes ago, ONIKKINEN said:

OSC dedicated astronomy cameras will still be significantly better in every aspect, so definitely worth it. For example Canon DSLRs have a red light blocking filter that passes only around 1/4th of Ha compared to dedicated astronomy cameras (or modded DSLRs). So you would be getting Ha at 4x speed compared to OSC. Mono with an Ha filter will be around 4 times faster than OSC, because every pixel will be capturing Ha as opposed to every 4th pixel of an OSC camera. So mono + Ha filter will be around 16x the speed of a DSLR and OSC will be around 4x the speed of a DSLR (ignoring other camera specs, in reality the difference is actually a bit larger because DSLRs are more noisy).

UV/IR cut filters for astronomy purposes fully pass Ha so you lose none of it when using one, so its not the same kind of filter found on DSLRs. In short: definitely worth it to upgrade from a DSLR.

Wow fantastic explanation Ty so much. I'll stick with latest plan of osc and sw 72ed then

Have you seen videos of people using smaller pixel (planetary cams I assume)  for DSO imaging?

[TiffsAndAstro]

3 minutes ago, 900SL said:

Cooled OSC has significant improvements over a DSLR. Improved Ha signal for starters, much less thermal noise, and ability to match calibration frames to temperature and gain. 

L2 filter is good for an APO unless you have poor colour correction. The L3 is the most aggressive. Check whether the camera has a UV/IR filter built into the sensor cover glass, some do, some don't.

I have an L Pro and never use it. It cuts out sections of the spectrum including broadband signal. I just use the L2 on OSC broadband targets, and take care not to overexpose 

Sounds good to me Ty. A cooled osc is way beyond my budget. I'm looking at zwo 585mc on flo website about £400.

I have seen a couple of videos of some £500 Blue cooled versions on AliExpress but I'm not keen.

[Elp]

My 183s are my workhorses at 2.4um pixel size are also at the smaller size. You'll have to use a pixel sampling calculator to find out what's best for your optical setup, off the top of my head a lot of cameras have around or just below 4um size pixels, the issue you'll have is undersampling and oversampling, as well as speed of photon registration per pixel. I don't tend to heed much attention to the numbers and theory but hands on experience has shown when imaging at say 300mm FL and the FOV it provides the cameras seem to have a better pixel response than imaging at 1000mm and the FOV, the reasoning is because at the shorter FL, signal is concentrated on fewer pixels so you get visually a brighter image, at the longer focal length that signal is spread out across the sensor so given the same amount of imaging time it will be dimmer in comparison but a higher resolution image. This is essentially why larger pixels tend to be more favourable for DSO as more photons hitting each individual pixel will theoretically generate more signal response so brighter perceived signal but people choose so the sampling is correct.

In this day and age you can't really go wrong with astro camera choice. The 585 will make for a good decent starter camera as I had the 485 and used it for both planetary and dso. The only issue with it was it's a 16:9 wide-screen aspect ratio so you might find you miss out on height if you've ever used other sensors. The small pixels will help if you decide to use it for planetary imaging.

Edited April 1 by Elp

[TiffsAndAstro]

3 minutes ago, Elp said:

My 183s are my workhorses at 2.4um pixel size are also at the smaller size. You'll have to use a pixel sampling calculator to find out what's best for your optical setup, off the top of my head a lot of cameras have around or just below 4um size pixels, the issue you'll have is undersampling and oversampling, as well as speed of photon registration per pixel. I don't tend to heed much attention to the numbers and theory but hands on experience has shown when imaging at say 300mm FL and the FOV it provides the cameras seem to have a better pixel response than imaging at 1000mm and the FOV, the reasoning is because at the shorter FL, signal is concentrated on fewer pixels so you get visually a brighter image, at the longer focal length that signal is spread out across the sensor so given the same amount of imaging time it will be dimmer in comparison but a higher resolution image. This is essentially why larger pixels tend to be more favourable for DSO as more photons hitting each individual pixel will theoretically generate more signal response so brighter perceived signal but people choose so the sampling is correct.

In this day and age you can't really go wrong with astro camera choice. The 585 will make for a good decent starter camera as I had the 485 and used it for both planetary and dso. The only issue with it was it's a 16:9 wide-screen aspect ratio so you might find you miss out on height if you've ever used other sensors.

My only xp is with 600d which is 3:2 and makes me want to be able to rotate for framing. A square sensor maybe the need to rotate is diminished a little.

Looks like I'll lose 10 megapixels though.

[Elp]

MP don't really matter, the most benefit you'll see is cleaner images. I had a 600D and never used it again after the astro cams. You will miss the FOV though and need a 294 or larger to get an equivalent, though I would not recommend a 294mc to a beginner due to calibration issues you'll get with it. The 533 is also nice though similar issue as with the 385/485/585, you'll miss the width on it but it does frame targets reasonably well.

[TiffsAndAstro]

3 minutes ago, Elp said:

MP don't really matter, the most benefit you'll see is cleaner images. I had a 600D and never used it again after the astro cams. You will miss the FOV though and need a 294 or larger to get an equivalent, though I would not recommend a 294mc to a beginner due to calibration issues you'll get with it. The 533 is also nice though similar issue as with the 385/485/585, you'll miss the width on it but it does frame targets reasonably well.

Currently my best lens for ap is a 200mm and with my 1.6 canon crop is effectively 320.

I'm struggling to compute a roughly equivalent crop factor for the zwo859mc. Will plug info into stellarium hopefully for a comparison 

[Elp]

Use astronomy.tools

[Elp]

And cross ref with Telescopius on targets