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Comet Filters

John

By John
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John

John

Posted
Posted (edited)

More specifically the Baader C2 Swan-Band:

Baader C2 Swan-Band Filter (15nm) OIII Parallel | First Light Optics

Has anyone used one of these for visual observing ?

Do they make a difference ?

From the information provided on the FLO website, it seems as if certain comet types may benefit more than others or possibly the benefits will be greater at certain points in a comets life cycle.

Thanks 🙂

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Littleguy80

Littleguy80

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I didn’t know Baader made a SWAN filter. I’ve only heard of the Lumicon version. The reports with the Lumicon are mixed and it’s very expensive. It sounds like for the right comet it can make a noticeable improvement but for others it will make little difference. This seems much more reasonably priced so I’m really tempted to give one a try. I really enjoy comets so quite excited to try one. Thanks for sharing :)

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Louis D

Louis D

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My Zhumell OIII filter is actually right shifted enough that it picks up the Swan bands better than the OIII bands.  I used it to help pick out C/2022 E3 (ZTF) in Bortle 7 skies.  It was all but impossible to pick out without it.  Of course, not every comet is as green as ZTF, so it may have been a special case.

You can see below how right shifted the Zhumell is relative to old and new Lumicon OIII filters.  If they are all this way (no guarantee), a used one might make for a good poor-man's comet filter.

427986663_LineFilters2.thumb.jpg.3746ae9b2ddbc18371f0e2e88df14d40.jpg

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Louis D

Louis D

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It also depends on how bright your skies are already.  If you're under Bortle 7 and up skies with lots of humidity as I am, about the best you can hope for is to be able to identify the coma amongst the murk by using a comet filter to suppress some of the background sky glow.

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  • 2 weeks later...
josefk

josefk

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I'm looking forward to your feedback on that @Littleguy80. Though on one hand i'm quite keen - anything that improves the view (or the chance of actual detection) of an ephemeral target like a comet where you may only get a few attempts at it has got to be good - on the other hand i'm in two minds considering how often (or not it would get used)...

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Littleguy80

Littleguy80

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43 minutes ago, josefk said:

I'm looking forward to your feedback on that @Littleguy80. Though on one hand i'm quite keen - anything that improves the view (or the chance of actual detection) of an ephemeral target like a comet where you may only get a few attempts at it has got to be good - on the other hand i'm in two minds considering how often (or not it would get used)...

It’s always a tricky one when it’s something a bit more specialised. At the same time, I don’t use my HB filter much but without it I wouldn’t have seen the California Nebula or Horse Head. 

The Lumicon SWAN filter was a lot more expensive which always put me off.  This was priced affordably enough for me to go for it. 

I’ve observed 26 comets since 2017 so I feel like they’re frequent enough to justify it. Plus I may have been able to pick up some fainter ones with this filter. 

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Louis D

Louis D

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8 minutes ago, Littleguy80 said:

Plus I may have been able to pick up some fainter ones with this filter. 

Again, using the blinking technique with stray ambient light blocked by a hood, and using a long eye relief eyepiece to fit the filter between your eye and the eyepiece, makes confirmation of faint comets (or bright comets in murky skies) easier.  The comet coma will be the only thing not dimming with the filter.  Interestingly enough, I find the comet disappears as I keep staring through the filter at it and have to blink it again to get it back.

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  • 2 months later...
John

John

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8 minutes ago, globular said:

@Littleguy80 How are you finding the Baader SWAN filter? 

I saw your post tonight regarding Comet C/2023 H2 Lemmon. You said you were using your Tak FC100DF and APM 30mm UFF - so an exit pupil of 4mm or so?  Is a large exit pupil key in activating the SWAN?  

I was just thinking the same when I read Neil's report. 

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Littleguy80

Littleguy80

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7 hours ago, globular said:

@Littleguy80 How are you finding the Baader SWAN filter? 

I saw your post tonight regarding Comet C/2023 H2 Lemmon. You said you were using your Tak FC100DF and APM 30mm UFF - so an exit pupil of 4mm or so?  Is a large exit pupil key in activating the SWAN?  

I’ve been pleased with it so far. There have been 3 comets that I’ve tried it on now. My approach to using it has been to treat it like a narrowband filter as it’s very similar to an OIII filter. The impression of the comets through the filter matches that. The filter takes a comet you can see without the filter and increases the contrast. Darker background so the comet stands out a bit more. I haven’t really felt like I could see a lot more of the comet with the filter. Whether this would change with a brighter comet or under darker skies, I can’t yet say. As with an OIII, you get green stars.  
There have been a couple of comets that I’ve failed to see without the filter and still couldn’t see with the filter. I’ll keep trying with this but so far it hasn’t made a difference with bringing dim comets into the visually detectable range. 
Overall, I’m pleased with it. The increased contrast makes for a nicer view. 

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globular

globular

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Thanks Neil.

4 hours ago, Littleguy80 said:

The increased contrast makes for a nicer view. 

 It sounds like it's doing it's job. I think I'll ask Santa for one 🎅

I get the impression from some other posters, about filters in general not specifically a swan filter, that there is an unreasonable expectation that filters should work miracles. Your description of it making a slight but noticeable difference to contrast, allowing you to see a bit more of it a bit more easily, is what I'd expect. 

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John

John

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1 hour ago, globular said:

Thanks Neil.

 It sounds like it's doing it's job. I think I'll ask Santa for one 🎅

I get the impression from some other posters, about filters in general not specifically a swan filter, that there is an unreasonable expectation that filters should work miracles. Your description of it making a slight but noticeable difference to contrast, allowing you to see a bit more of it a bit more easily, is what I'd expect. 

That's fair point.

The one that gets closest to being a "magic bullet" is a good O-III filter used on a receptive target such as the Veil Nebula. That can be quite a transformative experience 🙂

Edited by John
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Louis D

Louis D

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6 hours ago, Littleguy80 said:

There have been a couple of comets that I’ve failed to see without the filter and still couldn’t see with the filter. I’ll keep trying with this but so far it hasn’t made a difference with bringing dim comets into the visually detectable range. 

Messing around with my accidental comet filter (right shifted Zhumell OIII filter), it works best when trying to pick out the comet nucleus within a light polluted sky using the filter blinking technique.  This is the case for me with solar hugging comets that set just after the sun.  I have a large city directly west of me, mucking up the views in that direction.  When the comet is in a darker part of the sky, the difference is more subtle with the filter.  It allows me to confirm the extent of the coma more clearly.  Without it, the coma edge just indistinctly fades into the sky glow.

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