Jump to content

SkySurveyBanner.jpg.21855908fce40597655603b6c9af720d.jpg

Color filter + CLS filter?


Recommended Posts

Hello! Just got the svbony 7 filter set. I noticed that you can insert filter in sequence. Is it a good idea to always add the CLS filter?

Let's say together with the moon filter.

If so, does it matter if it comes first or last from the telescopes mirrors side?

Thanks 🙏

 

 

 

Edited by kdahl
Link to comment
Share on other sites

  • kdahl changed the title to Color filter + CLS filter?

CLS... city light supression. Basically it is another name for a LPR... light pollution reduction. I don't think it matters which way they go, but to save time, add the CLS first, then add the others as/if needed.

I do have a colour filter set, but I tend to use my Baader neodymium, contrast booster or variable polarising filters more when viewing the planets.

Edited by Philip R
Link to comment
Share on other sites

There's no CLS filter in the Svbony 7 filter set.  There's a CPL, or circular polarizer.  Is that what you meant?

It doesn't matter what order you stack them in.

The Moon filter is actually a Moon & Skyglow (M&SG) filter.  It's a generic neodymium filter.  When combined with a light yellow filter such as a #8, you will get an approximation of the Baader Contrast Booster.  The #12 in the set will cut out practically all blue light, while the #8 will cut mostly violet let, leaving most blue light.

If you have bought a separate CLS filter, it is basically a wider band-pass version of a UHC filter to combat light pollution and to slightly enhance the visibility of nebula.  I'm not aware of any useful color filter combinations with the CLS filter.

spacer.png

  • Like 1
Link to comment
Share on other sites

Here's a composite of images I took through my spectrograph of various filter combinations to give you some idea of what's possible with filter stacking:

1919071613_MoonSkyGlowVariations2.thumb.jpg.816633a4576fef6cd84da22cb90b014f.jpg

Figure that a Yellow #8 is going to be similar to the Yellow #12A which is currently unavailable new.

  • Like 1
Link to comment
Share on other sites

4 hours ago, Louis D said:

There's no CLS filter in the Svbony 7 filter set.  There's a CPL, or circular polarizer.  Is that what you meant?

It doesn't matter what order you stack them in.

The Moon filter is actually a Moon & Skyglow (M&SG) filter.  It's a generic neodymium filter.  When combined with a light yellow filter such as a #8, you will get an approximation of the Baader Contrast Booster.  The #12 in the set will cut out practically all blue light, while the #8 will cut mostly violet let, leaving most blue light.

If you have bought a separate CLS filter, it is basically a wider band-pass version of a UHC filter to combat light pollution and to slightly enhance the visibility of nebula.  I'm not aware of any useful color filter combinations with the CLS filter.

spacer.png

You are absolutely correct sir. It says CPL on it. What is the big difference? I can really only find compares between UHD and CLS. Thanks!

Link to comment
Share on other sites

1 hour ago, kdahl said:

You are absolutely correct sir. It says CPL on it. What is the big difference? I can really only find compares between UHD and CLS. Thanks!

Svbony has this blurb on that linked ad for the CPL filter:

CPL filter is mainly used for elimination of polarized; and enhances the contrast of the moon and planets in photographic images

Visually, I can't think of any use for a CPL filter in astronomy.  A variable polarizing filter is handy to vary the brightness of objects.  This can be useful for the moon, Jupiter, Mars, and Venus.  However, these filters are actually two linear polarizers back-to-back with a swivel attachment between them.

A CPL or circular polarizer is used in photography to cut through polarized reflections such as from a glass or water surface to image what lies beyond.  The circular part returns the light to being non-polarized after passing through the linear polarizer part, thus they can only be used in one orientation, linear polarizer facing the object.  This circular step is needed because polarized light really messes with light sensors inside the camera that are sensitive to polarized light.

Svbony should have just included a tradition neutral density moon filter instead.  These cut the brightness of objects by a fixed amount (generally 13% transmission or 87% attenuation) without changing the color balance.

Link to comment
Share on other sites

On 10/01/2023 at 22:51, Louis D said:

Svbony has this blurb on that linked ad for the CPL filter:

CPL filter is mainly used for elimination of polarized; and enhances the contrast of the moon and planets in photographic images

Visually, I can't think of any use for a CPL filter in astronomy.  A variable polarizing filter is handy to vary the brightness of objects.  This can be useful for the moon, Jupiter, Mars, and Venus.  However, these filters are actually two linear polarizers back-to-back with a swivel attachment between them.

A CPL or circular polarizer is used in photography to cut through polarized reflections such as from a glass or water surface to image what lies beyond.  The circular part returns the light to being non-polarized after passing through the linear polarizer part, thus they can only be used in one orientation, linear polarizer facing the object.  This circular step is needed because polarized light really messes with light sensors inside the camera that are sensitive to polarized light.

Svbony should have just included a tradition neutral density moon filter instead.  These cut the brightness of objects by a fixed amount (generally 13% transmission or 87% attenuation) without changing the color balance.

Thanks, hopefully the rest of the filter will aid me in normal viewing. Do you think I should invest in a CLS filter. I think that broader band works good, I am in 5 bartle zone.

Link to comment
Share on other sites

Tonight I compared my new Svbony UHC to my vintage Lumicon UHC on the Orion nebula.  The difference was very slight.  Both helped to bring out nebulosity in my Bortle 6/7 skies.

My new Lumicon OIII performed about the same as my vintage Lumicon OIII except that it didn't leak any red, so stars were simply green, not green/red, which was less distracting.

Either Lumicon OIII worked better than my Zhumell OIII, but not vastly so.  Stacking them darkened the background even more.  Any of the OIII filters brought out more nebulosity extent than either UHC from the background sky.

In short, the Svbony is a great tool to have in your astro toolbox for a great price.  The Lumicon OIII is also a best buy at its current closeout price with the moving sale discount code from Farpoint.

Edited by Louis D
Link to comment
Share on other sites

  • 2 weeks later...
On 09/01/2023 at 18:18, kdahl said:

Hello! Just got the svbony 7 filter set. I noticed that you can insert filter in sequence. Is it a good idea to always add the CLS filter?

Let's say together with the moon filter.

If so, does it matter if it comes first or last from the telescopes mirrors side?

Thanks 🙏

 

 

 

I've just got the SvBony  7 filter set. My other filters (Celesteron) have both male & female threads allowing for stacking. With this set are we supposed to remove the locking rings to stack them?

Rob

Link to comment
Share on other sites

No stacking is possible unless you pair it in front of a thicker filter with front female threads.  Don't remove the retaining ring unless you do it indoors over a cushioned surface in case the filter material drops out.  There's no guarantee that the revealed female threads are even 1.25" filter compatible.  If they are, and the stacked filter has long enough male threads to securely hold the filter material in place, you might get away with a fixed stack that night.  I would be hesitant to swap the stacked filter in the field in the dark for fear of losing the back filter material.

As a workaround, try attaching one to the filter threads of the eyepiece and hold the other between your eye and the eyepiece to quickly try different stacks to see which might be worth pursuing via other brands for one of the two filters.

Another option would be to put one filter on the front of the diagonal and one on the eyepiece if not using a Newtonian telescope.

On the plus side, they're lower profile, so they may fit in some filter wheels better.

They are also cheap relative to GSO made filters which do have front and rear threads.  These Svbony filters are also way cheaper than Baader, Lumicon, and Brandon color filters.

Edited by Louis D
Link to comment
Share on other sites


I think it is a good idea to always add the CLS filter. It is important that the CLS filter comes first from the telescope's mirror side, as it will help to reduce the amount of light pollution reaching the telescope. This will help to reduce the amount of light pollution that is picked up by the other filters, allowing for a more detailed view of the night sky.

Link to comment
Share on other sites

Adding the CLS filter all the time could be very detrimental for planetary viewing where light pollution doesn't matter much at all, but the cut out wavelengths (green through orange) could have conveyed a lot of detail.

Link to comment
Share on other sites

Many thanks for the information.

I did look at the amazon listing for the Svbony set and amongst the Q&As I found the following ".....you can't screw into each other(!) , because this Svbony ...filter set is a unilateral thread". That's me told then.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.