6 replies to this topic

[Zeeb]

Our local public recreational complex has a Celestron Origin on order (as well as a CPC 925) for a planned public astronomy program.   Due to an oversight, no nebula filter was specified for the Origin.  The Celestron filter is pricey but it appears optimized for the F2.2 system (per Celestron).  Does anyone know of a less expensive option that will do a good job on the most popular emission nebula, will not be too thick for the Origin holder and will not require manual focus?   Use will be under typical suburban skies.  Thanks.

[CraigR]

The Origin Nebula Filter at $219 (HPS and Agena) is actually the best price you're going to find for a fast, 1.25" dual narrowband filter. The Optolong L-eXtreme is a possibility but it's $259-$269 and you'd want to verify it's designed for an f/2 focal ratio.

 

This is one of the challenges (among many) with the Origin — you pay $4K and don't get everything you need in order to use it for its intended purpose.

[Zeeb]

Thank you, Craig.  Do you know if the Origin Nebula Filter would be useful for visual use also?  Does it have threads for a 1 1/4" eyepiece?

[bradhaak]

Not so much. You could use it visually, but there are differences between visual and astrophotography filters that make them less than ideal for the other.

 

I like the Antlia Quadband Anti-Light Pollution Filter. It's not as extreme as some of the dual band filters, and produces similar results as the Origin filter, but without the terrible halos. It usually runs about $200 USD.

[CraigR]

Not so much. You could use it visually, but there are differences between visual and astrophotography filters that make them less than ideal for the other.

 

I like the Antlia Quadband Anti-Light Pollution Filter. It's not as extreme as some of the dual band filters, and produces similar results as the Origin filter, but without the terrible halos. It usually runs about $200 USD.

I was under the impression that the halos around bright stars on the Origin were the result of the RASA design and not of the filter. Are there filters that somehow make them worse? That's terrifying. :-)

 

 

Thank you, Craig.  Do you know if the Origin Nebula Filter would be useful for visual use also?  Does it have threads for a 1 1/4" eyepiece?

Because astrophotography filters are optimized for long exposure photography, they aren't idea for human vision. Vision requires brighter images, so they typically have a wider bandpass.

 

You can look up the Origin filter, but I assume it's threaded. In fact I think I saw something that described it as being 6mm thick — the main body being 4mm and the threads being 2mm.

 

Caveat Emptor: I'm going a lot by what I read — I don't have direct experience with any of this. :-)

[bradhaak]

I was under the impression that the halos around bright stars on the Origin were the result of the RASA design and not of the filter. Are there filters that somehow make them worse? That's terrifying. :-)

 

 

The halos are present and an artifact of very fast scopes (from my reading). But, I do believe that the RASA design is especially prone to them.

 

However, the halos themselves are evidently caused by the reflective coatings on the filters themselves. And it turns out that Celestron's dual-band filter is one of the worst offenders. The 'clear' glass filter that comes with the Origin also has very bad reflections. So Origin users, myself included, have spent a lot of time and money trying different filters to determine the best alternatives. There are a number of threads in this forum discussing their relative merits. Unfortunately, some of them have very narrow apertures that don't let enough light through for the Origin to autofocus. The one I suggested does a decent job of both. It appears to produce similar results to Celestron's filter, it allows autofocusing, and it does a good job of controlling the halos.

 

Note that I said it controls the halos, not that it completely eliminates them. I don't believe this is possible. But they can be controlled to the point of being a non-issue.

Edited by bradhaak, 13 June 2025 - 04:58 PM.

[Goldypoker]

Not so much. You could use it visually, but there are differences between visual and astrophotography filters that make them less than ideal for the other.

I like the Antlia Quadband Anti-Light Pollution Filter. It's not as extreme as some of the dual band filters, and produces similar results as the Origin filter, but without the terrible halos. It usually runs about $200 USD.

Hey Brad,

When using the Antila Quadband filter (or, for that matter, any non Celestron filters)…do you switch the Origin into “filter mode”? If not, do you adjust the exposure time above the standard 10 seconds, or make any changes to the gain?