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Technical Aspects of the Triad Ultra Filter

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#51 johnsoda

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Posted 28 July 2019 - 08:01 PM

Hello, do you use the triad filter also when there is not a lot of light pollution? Is the triad only for when there is a bright moon or plenty of city lights? THANK YOU VERY MUCH FOR YOUR RESPONSE.

Depends.  If I get a rare clear moonless night, I usually do broadband, although it’s also influenced by the available targets. This time of year, there are a lot of narrowband targets.  In the Spring, not so much, so I’d be likely to do broadband on galaxies. Bottom line is that narrowband, no matter how you do it, opens up a lot of nights where you’d have a hard time doing broadband. 



#52 nateman_doo

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Posted 28 July 2019 - 08:26 PM

I use it only for nebula, to cut down on light pollution.  If I was at a dark sky sight I would not use the filter.  


Edited by nateman_doo, 28 July 2019 - 08:27 PM.


#53 Tothemoonalice

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Posted 28 July 2019 - 09:11 PM

I use it only for nebula, to cut down on light pollution.  If I was at a dark sky sight I would not use the filter.  

how much light pollution should one use NB over BB? like, from if I am in SImi Valley, somewhat outside of center of light pollution, but still have light pollution, would tri band help, or no?



#54 nateman_doo

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Posted 31 July 2019 - 05:48 PM

John...Can you take a crack at the Dumbbell nebula with the filter?  I am trying to figure out why there is such a drastic difference between the subs, and my stack.  

 

iZA1R1ph.jpg

 

for example... there is no blue in there at all.  No matter what I do (short of artificially coloring it)

 

Meanwhile here is without the triad, but an Optolong Moon/skyglow filter:

T4owk2mh.jpg


Edited by nateman_doo, 31 July 2019 - 09:10 PM.

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#55 nateman_doo

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Posted 31 July 2019 - 06:02 PM

The Wizard Nebula:

KNvYDQMh.jpg


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#56 nateman_doo

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Posted 31 July 2019 - 10:25 PM

M16 moon and sky glow filter:

gYbVxG5h.jpg

 

M16 with triad:

B7mEwxdh.jpg?1


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#57 johnsoda

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Posted 01 August 2019 - 11:16 AM

John...Can you take a crack at the Dumbbell nebula with the filter? I am trying to figure out why there is such a drastic difference between the subs, and my stack.



for example... there is no blue in there at all. No matter what I do (short of artificially coloring it)

Meanwhile here is without the triad, but an Optolong Moon/skyglow filter:


Planetary nebulae are not the best objects for narrowband, including the Triad. There’s no true blue with the Triad, since none of the bands are in the blue part of the spectrum. You can do some interesting things with the Triad on M27, but if you want a good representation, you need to do broadband with little moonlight.



#58 johnsoda

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Posted 01 August 2019 - 11:20 AM

Here’s M27 with different filters.  Click on the image.  Interesting, but either RGB or OSC is the way to go. 

 

get.jpg?insecure



#59 nateman_doo

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Posted 02 August 2019 - 10:00 AM

I got an answer that is similar to yours from the manufacturer.  They said that it lacked Hbeta.  but had O3 and Ha.  Veil has plenty of O3 and Hbeta

 

anyhow I added more data to it:

kvKGNi7h.jpg


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#60 johnsoda

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Posted 11 August 2019 - 10:09 AM

Image taken with the Triad Ultra in the Imaging Challenge here


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#61 johnsoda

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Posted 06 September 2019 - 09:05 AM

Click on image for better quality image and acquisition details.

 

get.jpg?insecure


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#62 johnsoda

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Posted 19 September 2019 - 07:03 PM

Click on the small image for a better quality image and acquisition details. 

 

get.jpg?insecure

 

 

 

 

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#63 AKHalea

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Posted 20 September 2019 - 08:18 PM

  • Inability to vary exposure times for the various bands due to different signal strengths.  Obviously, you're always getting the same exposure times for all narrowbands with this filter.  This is a serious issue if you want equally "bright" exposure for the various bands.  You can stretch the channels separately, but this creates noise issues.  Frankly, this might be the only reason I might use my single narrowbands in the future on certain targets. 

Advantages:

 

  • Biggest is simplicity.  As I mention above, you can get very good results with one filter, no filter wheel, one set of lights, one set of flats, simple processing, and one focus point (with the caveats above).  This not only make things simple - it makes the process faster.  It also gets more people involved in astrophotography, which is a good thing for all of us.
  • Disk space.  Having multiple sets of flats and lights, one for each filter, starts to really add up.
  • Cost - this is going to make people laugh, I'm sure.  However, compared to my set of Astrodon narrowbands and filter wheel, this filter is much cheaper.  I'm sure I'll get arguments that you don't need Astrodons, but I would argue that any set of filters worth having, and possibly buying a mono camera if you don't have one, will be much more than the cost of this filter.
  • Speed in autofocus and platesolving - a surprise for me is how short my exposures can be for autofocusing and platesolving, compared to one narrowband.  I think this is because starlight comes from four different narrowbands with this filter, and stars are all you care about for autofocus and platesolving.  My autofocusing and platesolving exposures with this filter are the same binning and exposure time as I use for Lum or no filter.

If you have a good color astrocamera and want to get into narrowband work, I would seriously look at this filter.  Even if you have have narrowband filters and a mono camera, you might be interested.  I'm not sure how much use my single narrowband filters are going to get in the future.  Frankly, this filter is a lot more fun to use.


 

Hello John, 

 

Thanks for starting this thread. I have been a user of this sort of multi-narrow band filter for the last 2 years (though not the Triad). But I had the same idea for capturing images with a DSLR using a filter that uses all 4 pixels in the Bayer matrix. The filter I use, is available from Omega Optical and has a 12nm wide HA bandpass and has a 475-500nm bandpass for combined H-Beta and OIII lines. Since it blocks the Hg lamp LP line in the blue/green, but is wider otherwise, I thought it might help me capture more of the blue/green emissions. I thought this might be a good thing bacause OIII and H-Beta lines are quite weak in many emission nebulae and more of the signal in that area might help get a better color image. 

 

For me, this filter has opened up emission nebula imaging with my HA-modded DSLR (Nikon D5300). It has made imaging emission nebulae very simple and processing quite straight-forward. And I like to avoid complexity if possible! Here is an example of the image taken with this filter and my DSLR : The Pelican nebula (post#7 submitted for Goofi's August 2019 challenge). Another example is the recent capture of the Lagoon nebula (M8) : 

 

8-26 Lagoon BiColor 114Min csc STCrJ CN1.jpg

 

So, I am a happy camper. There are a few limitations of this filter (and other similar multi-band filters like Triad). One of them, as you correctly point out, is the fact that one cannot selectively change the exposure for different emission lines. Since HA is usually strong in many emission nebula, OIII tends to be much weaker and does not get sufficient exposure time when using this filter. I am thinking of mitigating that by taking additional time on the target using an OIII filter with the DSLR. Obviously, it is not as efficient as when using a mono camera, but still, I think it will help. So, that is the plan going forward. Cheers ..... Anil


Edited by AKHalea, 20 September 2019 - 08:24 PM.

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#64 johnsoda

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Posted 06 October 2019 - 10:06 AM

M31 in narrowband is kind of interesting.  Might get some more hours on this to knock the noise down a bit.

 

get.jpg?insecure

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#65 johnsoda

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Posted 06 October 2019 - 10:14 AM

Compare this with HaRGB:

 

get.jpg?insecure


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#66 johnsoda

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Posted 10 October 2019 - 08:06 PM

Added much more integration time.  In fact, it’s a new high for me for integration time on an image.   Did knock the noise down and there’s more detail. 
 

get.jpg?insecure

 

 

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#67 Creedence

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Posted 10 October 2019 - 08:22 PM

That’s an amazing result. I’m doing the same with M33 right now. I’ve got about 3 hours on it with the Triad Ultra and it does an incredible job of pulling out emission nebulae as it has with your image. It really adds an interesting dimension.

#68 johnsoda

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Posted 10 October 2019 - 08:30 PM

That’s an amazing result. I’m doing the same with M33 right now. I’ve got about 3 hours on it with the Triad Ultra and it does an incredible job of pulling out emission nebulae as it has with your image. It really adds an interesting dimension.

Yeah, normally I’d say it’s not a good filter for galaxies, but it’s interesting to use it on the galaxies with larger apparent sizes where you can get details.   It does take time, though, just as with any narrowband filter. 



#69 johnsoda

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Posted 10 October 2019 - 08:33 PM

I should point out that there was no sharpening or noise reduction applied on that image. Just standard calibration, drizzling, and stretching. 



#70 johnsoda

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Posted 15 October 2019 - 05:28 PM

Click on small image for acquisition details and better quality image. 
 

get.jpg?insecure

 

C8F779FB-F145-490C-879D-4C3EAD756371.jpeg


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#71 nateman_doo

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Posted 15 October 2019 - 06:04 PM

Ugh, that Andromeda is amazing!

 

eG7gj9wh.jpg

tnV0x7gh.jpg

 

My elephants Trunk, and Cygnus wall.  They were the same color, but I messed with the Hugh of the cygnus wall just so I didnt have to keep seeing the same color.




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