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Thalestris24

Filters with EAA?

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I usually use an IDAS P2 filter for my EAA imaging, be it mono or OSC.

My problem with narrow band, both for EAA and regular imaging, is that it is SO SLOW, which seems o defeat the object, to some extent.

Edited by AKB

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1 minute ago, AKB said:

I usually use an IDAS P2 filter for my EAA imaging, be it mono or OCS.

My problem with narrow band, both for EAA and regular imaging, is that it is SO SLOW, which seems o defeat the object, to some extent.

Hi

Yeah, I was thinking about the uhc which is 'broad' narrowband or maybe a baader 610nm longpass red with a uv/ir cut? I have the latter but not tried it yet. Also thought a uhc might be ok with a colour camera. I've been mulling over getting a colour camera for eaa eg a 183, but have terrible lp here so colour might not be such a good idea unless I can filter most of the lp….

Louise

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8 minutes ago, AKB said:

I don't have so much of an issue with LP, but before getting the IDAS, I did use a Baader UHC just to help out a bit.

I have also used an IR-pass filter (685 nm cut-off) ...

https://www.firstlightoptics.com/uv-ir-filters/baader-ir-pass-filter.html

...but not enough to speak eloquently  about its virtues.

I've used IR pass as well. Certainly beats the lp but only suitable for a few targets and also maybe too slow for eaa. How was the uhc - did it increase nebula contrast?

Thanks

Louise

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2 hours ago, Thalestris24 said:

How was the uhc - did it increase nebula contrast?

Yes, I believe that it did, although I seem not to have posted comparative shots (I must have them somewhere.)

I did post results from an EAA session with UHC here:

 

Edited by AKB

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20 minutes ago, AKB said:

Yes, I believe that it did, although I seem not to have posted comparative shots (I must have them somewhere.)

I did post results from an EAA session with UHC here:

 

Looks pretty good! I wonder how one would cope with red zone lp… I suppose I'll have to get one at some point and try it.

Thanks

Louise

Edit: Suddenly remembered I bought a 1.25" Astronomik uhc some years ago. Just have to find it...

Edited by Thalestris24

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It depends on the target? A while since I did my (old fashioned!) EAA
with my Watec B&W Camera. I have used standard narrow HA & OIII
to advantage and stacked/combined images as in "classical" imaging. ?

Since then, I have become accustomed to using both Baader LP filters
and increasingly a Baader UHC (35nm HA plus OIII filter!) But more for
Wide-Field imaging with (std. colour) DSLR. The Baader UHC was great
for removing the *Orange* light pollution while preserving nebulosity!
The filter has pretty much 100% transmission in HA and OIII and quite
a bit more besides (to focus on!) in the "wings" of these passbands... ?

The main advantage here was that the Baader UHC was effective at
removing local Orange street lighting. But, of course, this has now
been replaced by the new (wretched) broad-band white light LED's. ?

I suspect too that reflection nebulae and many galaxies, rely more
on light emission in the Yellow region. Older galaxies have a lot of
G, K, M spectra class stars etc.  Light from these would be reduced
by the "orange notch" of the UHC and is probably quite similar to
the (seemingly quite) yellowish cast of modern WL street lighting. 

I guess ALL ANY of us can so is try things out in practice? I  bought
a Baader IR (685nm) for Lunar imaging. Over the last couple of yrs., 
I have mostly been HA Solar imaging, but the Sun is now at a Solar
"minimum". Perhaps I WILL have to get into Lunar Imaging more? ?

Edited by Macavity
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Thanks! I'm probably being overoptimistic to think I might even glimpse an emission nebula in my Bortle 9 skies... Still, (if I can find it) I'll have a go with my Astronomik uhc and/or Baader 610nm.

Louise

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On 18/12/2018 at 09:20, Thalestris24 said:

Anyone had any experience of using LP/UHC/Narrowband filters?

Louise

Hi Louise,

I would recommend that you try a narrowband Ha filter for EAA viewing of emission Nebulae.  The Orion 7nm is a good bargain and performs very well.  The filter blocks all light outside that narrow band centered around the wavelength of 656.28nm, so it’s the best LP filter available, but only works on emission Nebulae.  The speed should not be significantly affected for emitted Ha light because the transmission at that wavelength should be greater than 90%.  Even with the great skies we have here in Hawaii, the filter helps on those nights with a bright moon.  It’s best to use the NB Ha filter with a mono camera, but I have gotten some good results with a OSC camera as well.  With the Bayer mask on a color camera, only the red lens will pass the Ha light, but most cameras will do some interpolation for the other three.  Resolution is reduced, but not as much as one would think.  Here is a link to one of my albums of NB Ha captures using a Lodestar 2X mono.

Don

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29 minutes ago, HiloDon said:

Hi Louise,

I would recommend that you try a narrowband Ha filter for EAA viewing of emission Nebulae.  The Orion 7nm is a good bargain and performs very well.  The filter blocks all light outside that narrow band centered around the wavelength of 656.28nm, so it’s the best LP filter available, but only works on emission Nebulae.  The speed should not be significantly affected for emitted Ha light because the transmission at that wavelength should be greater than 90%.  Even with the great skies we have here in Hawaii, the filter helps on those nights with a bright moon.  It’s best to use the NB Ha filter with a mono camera, but I have gotten some good results with a OSC camera as well.  With the Bayer mask on a color camera, only the red lens will pass the Ha light, but most cameras will do some interpolation for the other three.  Resolution is reduced, but not as much as one would think.  Here is a link to one of my albums of NB Ha captures using a Lodestar 2X mono.

Don

Hi

Thanks. I have several Ha filters and mono cameras - I just wondered if anyone had managed to do eaa (in urban skies) using them. I've set up a camera with a uhc filter to try wideband narrowband eaa. I may try reducing the width of the far red with an additional filter. Just waing for the fog and clouds to go away...

Happy holidays!

Louise

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Hi Louise, 

A bit late on this one, I have used an Ha filter with a few scopes for EAA, the best results I have had are with small fast fracs. The 60mm achro finder/guider at native F3.75 produced really good results:

http://m.ipernity.com/#/doc/robivory/39820544/in/album/862148

The 72mm Semi-apo frac reduced to F3.75 was also really good:

1E6C3915-A0DC-489D-A1AE-518C07EDB641.png.08a073eff250f60ec9c077aebb882831.png3006DBF4-6AF2-4923-AA7D-4F7FDD25038F.png.5e9d52ca9d82764cc6f880825bbf3a98.png

The brightest nebulae obviously produce the nicest results in short EEA exposures. The larger scopes did not seem to perform so well, possibly because I could not make them as fast, and possibly because I was trying more challenging objects. 

I like the ultra simple simple setup of the finder/guider + lodestar +Ha. ?

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2 hours ago, RobertI said:

Hi Louise, 

A bit late on this one, I have used an Ha filter with a few scopes for EAA, the best results I have had are with small fast fracs. The 60mm achro finder/guider at native F3.75 produced really good results:

http://m.ipernity.com/#/doc/robivory/39820544/in/album/862148

The 72mm Semi-apo frac reduced to F3.75 was also really good:

1E6C3915-A0DC-489D-A1AE-518C07EDB641.png.08a073eff250f60ec9c077aebb882831.png3006DBF4-6AF2-4923-AA7D-4F7FDD25038F.png.5e9d52ca9d82764cc6f880825bbf3a98.png

The brightest nebulae obviously produce the nicest results in short EEA exposures. The larger scopes did not seem to perform so well, possibly because I could not make them as fast, and possibly because I was trying more challenging objects. 

I like the ultra simple simple setup of the finder/guider + lodestar +Ha. ?

Hi Robert

Those are encouraging! I'm still waiting for some clear skies to try out  uhc filter, possibly combined with an idas d1. My f6 frac is in need of a reducer.  Also still waiting to try the f4 Takumar. At the moment, there are no clear skies forecast before Jan 2nd, at least :(

Happy New Year!

Louise

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49 minutes ago, Thalestris24 said:

Hi Robert

Those are encouraging! I'm still waiting for some clear skies to try out  uhc filter, possibly combined with an idas d1. My f6 frac is in need of a reducer.  Also still waiting to try the f4 Takumar. At the moment, there are no clear skies forecast before Jan 2nd, at least :(

Happy New Year!

Louise

Ah well, at least the moon should be gone by then! ?

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10 minutes ago, RobertI said:

Ah well, at least the moon should be gone by then! ?

It will probably be bright again by the time I might get any clear skies :(

 

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