Are these coloured filters useful for AP?

[Quetzalcoatl72]

I got these in a neat eyepiece carrying case by Celestron, but I never really used them, just the moon filter a couple of times. There's no special name on them just the colour of the filter and a number. They're official Celestron so I assume they are of some quality but are they worth using for astrophotography in any way? was thinking of just selling them.

[vlaiv]

Before interference filters - people used absorption filters. Even now, bayer matrix on color sensor is made up out of absorption filters rather than interference ones.

If you have mono camera - you can use red, green and blue filters or even some other combination to capture color. You only need to calibrate your data properly.

Only drawback is lower quantum efficiency of these filters. Interference filters often pass 95-98% (some claim even 99%) of their respective band, while these filters - pass less - some even below 60%.

You can find their curves online. For example #80A (light blue) has following transmission curve:

#58A green:

#25 Red has this one:

And so on ...

While interference filters have steep cut offs in their transmission curves - don't think that sloped curves are somehow inferior. In fact - they often help with color reproduction if properly calibrated.

 

[Quetzalcoatl72]

1 minute ago, vlaiv said:

Before interference filters - people used absorption filters. Even now, bayer matrix on color sensor is made up out of absorption filters rather than interference ones.

If you have mono camera - you can use red, green and blue filters or even some other combination to capture color. You only need to calibrate your data properly.

Only drawback is lower quantum efficiency of these filters. Interference filters often pass 95-98% (some claim even 99%) of their respective band, while these filters - pass less - some even below 60%.

You can find their curves online. For example #80A (light blue) has following transmission curve:

While interference filters have steep cut offs in their transmission curves - don't think that sloped curves are somehow inferior. In fact - they often help with color reproduction if properly calibrated.

 

Interesting, so the numbers do have a meaning. I'm not sure I'll use a filter wheel, my location is just not worth it I don't think. All my cameras are MC, cuiv the lazy geek on youtube uses a 533mc with filterwheel, not exactly sure what he's doing there but he lives in a white zone!

[Alan64]

Several years ago, I got the cream-of-the-crop in coloured filters: Lumicons, made in Japan, save the 80A Blue which was delivered about two or more years later, and made in the U.S....

Reputedly, the two yellow filters are good for suppressing false-colour with short, "fast" achromats.

In all these years, I've rarely, if ever, used a single one.  The darker and darkest filters are used with telescopes of much larger apertures.

[AstroMuni]

9 hours ago, Quetzalcoatl72 said:

the lazy geek on youtube uses a 533mc with filterwheel, not exactly sure what he's doing there but he lives in a white zone!

Besides colour filters there are also filters available for light pollution, IR, Ha, Oiii etc. So probably he/she uses those