Light filter advice

[Kenboy]

Hi all 

I'm looking for a budget light filter so I can start using my set up in my back garden 

I'm using an astro-modified Canon 550d + Canon 50mm F/1.8 lens on a star tracker. I'm in Bortle Class 5 skies. 

Any advice for this? 

Thanks!

[barbulo]

Hi @Kenboy

Bearing in mind that filters limit the amount of light you are receiving, what do you want to filter out? 

If it is Light Pollution (Bortle 5 is not bad at all), you can look for UHC or CLS filters.

If you want to boost faint objects like emission nebula, you could go for dual band such as L-enhance or L-extreme.

But remember that filters will imply longer exposures.

[Starwiz]

1 hour ago, barbulo said:

But remember that filters will imply longer exposures.

The Astronomic CLS filter has a loss of about 8%, so you would need to expose for about 8% longer to collect the same amount of the target light you want to collect.  However, the main reason for longer exposures with a light pollution filter is that now you CAN expose for much longer without being swamped by the light pollution.

John

[Kenboy]

Hi guys 

thanks for your advice 

can I just check

my 550d is astro-modified (rear filter removed) 

so is this the one to go for -> Clip filter for Canon EOS APS-C £116 (https://www.firstlightoptics.com/light-pollution-reduction/astronomik-cls-filter.html) 

[Starwiz]

10 hours ago, Kenboy said:

Hi guys 

thanks for your advice 

can I just check

my 550d is astro-modified (rear filter removed) 

so is this the one to go for -> Clip filter for Canon EOS APS-C £116 (https://www.firstlightoptics.com/light-pollution-reduction/astronomik-cls-filter.html) 

I've got the Canon 1200d (also astro-modified) and the clip in filter does the job.  When I used my DSLR with the CLS filter I was doing up to 15 minute exposures in a Bortle 4.5.

It looks like this:

https://www.astroshop.eu/broadband-filters/astronomik-filters-clc-canon-eos-clip-filter-aps-c/p,16744

John

[Kenboy]

2 hours ago, Starwiz said:

I've got the Canon 1200d (also astro-modified) and the clip in filter does the job.  When I used my DSLR with the CLS filter I was doing up to 15 minute exposures in a Bortle 4.5.

It looks like this:

https://www.astroshop.eu/broadband-filters/astronomik-filters-clc-canon-eos-clip-filter-aps-c/p,16744

John

Amazing thanks! 

[Kenboy]

https://www.highpointscientific.com/astronomik-cls-canon-eos-xt-clip-filter-cls-eos-xt

On this website it says this filter is designed for use with lenses of all apertures, operating at f/3 and above

does this mean I can't use it for my canon 50mm f/1.8 lens? 

[Starwiz]

On 02/02/2022 at 10:17, Kenboy said:

https://www.highpointscientific.com/astronomik-cls-canon-eos-xt-clip-filter-cls-eos-xt

On this website it says this filter is designed for use with lenses of all apertures, operating at f/3 and above

does this mean I can't use it for my canon 50mm f/1.8 lens? 

I'm no expert on this, but logic would tell me that you should be OK if you change the aperture to 3 or above on the lens.  This would obviously let a little bit less light in, but you'll be exposing for much longer anyway.

John

[Starwiz]

This was my first image with the CLS filter in place.  It was captured in the UK six years ago.  Orion was low down in the sky and there was an orange street lamp just below where I was imaging, so it shows how good the filter is.

John