21 replies to this topic

[nsubin]

Hello! 

 

My current rig is:
WO Flt 132
WO Flat 8 flattener and reducer
AM5n mount
ZWOASI2600MC Air
ZWO EAF

 

Pixinsight

RC Astro Suite

 

I live in the Far West Texas in a Bortle 1 zone. 

 

My question is would a filter like an Optolong L-enhance improve my images (espcially nebulae)?

 

I love the hobby and am only 6 months into a real rig (started with an Evscope, then a Seestar S50 and now this. I would appreciate any feedback.

 

Thanks

 

Neil

Edited by nsubin, 28 April 2025 - 02:55 PM.

[soojooko]

From a Bortle 1 location, you don't really need to use anything. I use an L-Enhance from a B4 location and the difference is marginal.

[Jim Waters]

Welcome to Cloudy Nights.

[Smalone]

In general for B1 skies you need a UV/IR for galaxies and stars clusters, also some galaxies, the addition of HA filter will add red that the UV/IR blocks. Nebula's I us the UV/IR to get stars and HA/Oiii and Oiii/Sii for the nebula. The UV/IR will blocks most light transition that is Ha, Oiii and Sii. Someone mentioned this to me and I have tested the filter when I went to a B1 site, and yes there is a difference. The L-enhanced will help but take some time and look at the light transmission of filters. I ended up with 2 sets, the  Antlia ALP-T Dualband 5nm Filter Set - Ha/OIII & SII/HB, processing with this set is a bit of a pain. Most other sets don’t have Hb data but have another Oiii transmission from the second filter. The other is Askar Colour Magic 2" Duo-Narrowband 6nm D Package which I prefer over the Antila. Both work great no large halos around stars but processing with the Antila is harder for me.

[Spaceman 56]

I live in the Far West Texas in a Bortle 1 zone. 

 

My question is would a filter like an Optolong L-enhance improve my images (espcially nebulae)?

 

Neil

Hello Neil.

 

from where you live, with your nice dark B1 skies, you can image without filters.   

 

Trust me on this.  

[Zambiadarkskies]

as a fellow Bortle 1 imager here is my take: 

 

- The most beautiful targets to me are dim and dusky dark and reflection nebulae, areas with IFN etc.  Stuff that really cries out for no filter (when I say no filter I mean with an IR/UV cut of course). 

- These beautiful targets are not everywhere! 

- The moon comes out in B1 skies the same like anywhere else 

- Emission nebula are pretty much all over the place at the right times of the year and they too are beautiful targets 

- Which are accentuated by interference filters.  And with all such filters, the narrower the better 

- These filters add contrast and SNR, reducing background noise and reducing the number and size of stars which can at times dominate a nebula image

 

So a tight dualband Ha/Oiii ( I would not worry about Sii/Oiii for a good while yet. If ever) gives you options and will improve certain images.    It is not "needed" but then exactly what is...? 

 

If you have been at it for 6 months then you have probably come across some of the targets and circumstances that I describe, where a filter will give options.  Remember that a ton of people are coming at this from the PoV of occasional dark sky trips where of course you are going to go after targets that benefit the most from such skies - those being of course the ones most suited to no filter use.   If you actually live there it is a different story. 

 

Don't bother with the Enhance.  Get the tightest you can.  Think about this:  People don't get worked up about mono imagers swapping out their LRGB filters for SHO filters under dark skies, but for some reason OSC narrowband under dark skies just triggers people.  It is a mystery to me. I use a L-Ultimate quite often (a 3nm filter so as tight as it gets for OSC really).  It gives some people fits of conniption but I do okay with it on certain targets.  Okay, I exaggerate about the conniption  

 

Sample below using an L-ultimate.  Plenty more on my Astrobin. 

 

[Spaceman 56]

Great image above from Zambia.

 

I like shooting Galaxies in OSC. also from Bortle 1.

 

 

No Filters used on this recent test shot of NGC-1365.   

Edited by Spaceman 56, 29 April 2025 - 01:50 AM.

[Zambiadarkskies]

The original question posed by Neil was "My question is would a filter like an Optolong L-enhance improve my images (especially nebulae)?"  

 

Here is a demonstration that illustrates my above answer.  Now forget about color preferences, one can make colours whatever one wants.  If star colour is an issue you can shoot RGB stars (which I often do).  This is to try and illustrate where I said (in the context of emission nebula) " ...Which are accentuated by interference filters.  And with all such filters, the narrower the better.  These filters add contrast and SNR, reducing background noise and reducing the number and size of stars which can at times dominate a nebula image"  

 

These are single subs.  The narrowband is 300s and the BB is 120s.  The NB was two nights ago, the BB was last night.  Processing as similar as possible, which comprised debayer, BXT correct only, BXT stars and nebulosity, remove stars, stretch starless just using an unlinked STF to histogram transformation (to accentuate the Oiii component in both images).  Stars stretched using GHS and then re-combined in Ps.  

 

If you look at the nebulosity detail alone, then to my eyes the use case is clear.  Now I am not saying the L-Ultimate is the answer to everything, I am actually shooting Carina now in broadband and not using the filter.  But the effect of a narrowband filter is undeniable.  But the caveat of course is getting comfortable with imaging and processing is probably a good thing to do before starting to play with filters.  But  hopefully I have answered the question asked.    

 

120s with IR/UV cut 

 

300s with L-Ultimate

Edited by Zambiadarkskies, 29 April 2025 - 05:44 AM.

[imtl]

Great image above from Zambia.

 

I like shooting Galaxies in OSC. also from Bortle 1.

 

NGC-1365- DR and ACRH2 HQ Closer 2025 V2.jpg

 

No Filters used on this recent test shot of NGC-1365.   

Although a nice picture, the OP was asking about filters for nebulae. For galaxies no one should use filters no matter what bortle scale they image from. So not relevant here.

[imtl]

To the OP, you will benefit from a tight narrow-band filter for OSC when imaging emission nebulae. There are quite a few options these days.

[Helyis]

Although a nice picture, the OP was asking about filters for nebulae. For galaxies no one should use filters no matter what bortle scale they image from. So not relevant here.

That's not totally true, many galaxies will have Hii regions in them, and adding Ha and even Oiii data can enhance them, a nice addition to the image (I know you know that).

So while no one should only image a galaxie using narrowband, adding narrowband data to good (L)RGB data can be a plus. Albeit, not for begginers, as the post processing can be a nightmare

Overall, I 100% agree with ZambiaDarkSkies

Edited by Helyis, 29 April 2025 - 07:24 AM.

[imtl]

That's not totally true, many galaxies will have Hii regions in them, and adding Ha and even Oiii data can enhance them, a nice addition to the image (I know you know that).

So while no one should only image a galaxie using narrowband, adding narrowband data to good (L)RGB data can be a plus. Albeit, not for begginers, as the post processing can be a nightmare

Overall, I 100% agree with ZambiaDarkSkies

That is, of course, totally correct but as you mentioned, hardly recommended for beginners.

So I will make my post clearer. To capture broadband info, don't use filters no matter what bortle scale you image from. In specific cases, adding narrowband info to the broadband could enhance the image quite a bit.

Edited by imtl, 29 April 2025 - 07:28 AM.

[ntph]

Eyal’s last paragraph should be pinned in big bold font. Or get some AI to spot these questions and post the same. 

[nsubin]

Thanks all so much for the feedback. One more quesion, are there scripts in PI that would help offset the processing challanges mentioned when using the filter?

[nsubin]

 

still working on my processing and integration times (need to have more patience)

thanks again!

[Spaceman 56]

 the OP was asking about filters for nebulae.

Ok. Here is a nebula shot taken without filters from B1.

 

 

Low quality 500kb version.

[Spaceman 56]

Here is another Nebula shot taken without filters. 

 

Low Quality version.

 

 

this ones not as good, but its an old shot. 

 

 

[imtl]

Ok. Here is a nebula shot taken without filters from B1.

Helix no filters LQ v2.jpg

Low quality 500kb version.

Great. And if you had put a narrowband filter you would have gotten better contrasted data to work with which potentially gives you more detailed image. If you know how to process it.

No one is saying you can't image without filters, the point is that proper filters will give you better data to work with.

Edited by imtl, 30 April 2025 - 06:13 PM.

[Zambiadarkskies]

Ok. Here is a nebula shot taken without filters from B1.

 

Helix no filters LQ v2.jpg

 

Low quality 500kb version.

Here is one with an 80mm aperture....  With (dare I say) a filter.  80mm.  Vs 250mm

 

[Zambiadarkskies]

Another one.  You cannot do this with no filters.  Like it or not.  

 

[Zambiadarkskies]

The OP asked about the advantages of filters....  There are some.     

[Spaceman 56]

Hey Zambia, I think we have proved the point.

 

You can image from Bortle 1 with Filters if you want to.  

 

You can also image from Bortle 1 without filters if you want to.   

 

Generally speaking I find Filter images look too extreme, regarding colour, (and often contrast) but they can be done well, and you have often done so.   

 

For myself I prefer OSC images without Filters. I think they look better, but that is just my opinion.