Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Hydrogen Alpha filters for NV

  • Please log in to reply
28 replies to this topic

#1 GOLGO13

GOLGO13

    Skylab

  • *****
  • topic starter
  • Posts: 4277
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 17 September 2019 - 10:46 AM

So I have the really nice 5nm Astrodon HA filter I've been using in my orange sky. Is there any benefit to having another HA filter in a larger nm like 12 or 7 etc? And in what situations would you use one over the other?

 

I've got things covered on the IR pass filter side of things, but I only have the one filter on the HA side.

 

Thanks



#2 Mazerski

Mazerski

    Vostok 1

  • ****-
  • Posts: 198
  • Joined: 13 Nov 2013

Posted 17 September 2019 - 11:28 AM

I don’t have the 5 but DO have the 6, 7 and 12. I had the 7 first - I use all 3 as it just depends on hand-held vs. scope and in each case, Mod3 vs. PVS7. Of course the sky condition matters — my area is SW of Baltimore and NE of Washington DC. LP central.

 

Orange sky - does that mean severe LP?

Not suggesting you buy anything - just saying with multiple devices and various scopes, I use all 3 Ha filters.



#3 GOLGO13

GOLGO13

    Skylab

  • *****
  • topic starter
  • Posts: 4277
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 17 September 2019 - 11:51 AM

Orange is pretty strong light pollution, but not quite as bad as being near a big big city. No milky way really without NV. So not very dark. I used to live 12 miles from St. Louis and that was worse for sure. But where I am now is still pretty light polluted.



#4 Mazerski

Mazerski

    Vostok 1

  • ****-
  • Posts: 198
  • Joined: 13 Nov 2013

Posted 17 September 2019 - 12:01 PM

Surely one of the others that use NV also have the same sky condition as you and can offer solid advice. I think my are is a white zone. Summer nights - at times I can only see maybe 8-10 stars (more stars visible in winter). Its terrible.



#5 GOLGO13

GOLGO13

    Skylab

  • *****
  • topic starter
  • Posts: 4277
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 17 September 2019 - 01:40 PM

Which one do you like to use for the North American Nebula?


  • RVA_Chris likes this

#6 slavicek

slavicek

    Mariner 2

  • *****
  • Posts: 241
  • Joined: 01 Aug 2017
  • Loc: Massachusetts

Posted 17 September 2019 - 02:11 PM

I have 3.5, 5, 7 and 12nm filters. So far, the 5nm filter is giving me best results regardless of the light polution of the sky. And also regardless what nebula I am looking at. It probably gives the best balance between how narrow the bandwidth is and how much you starve the NV of photons. So I would say: You are good with what you have.



#7 The Ardent

The Ardent

    Aurora

  • *****
  • Moderators
  • Posts: 4507
  • Joined: 24 Oct 2008
  • Loc: Virginia

Posted 17 September 2019 - 02:15 PM

Any is better than none.

#8 Mazerski

Mazerski

    Vostok 1

  • ****-
  • Posts: 198
  • Joined: 13 Nov 2013

Posted 17 September 2019 - 02:28 PM

Since the NA Nebula is so big, to see it you need the hand held method **... with PVS7 I use the 12nm and with the Mod 3 the 6 or 7nm... it also depends on how high in sky any object is due to the crappy east coast skies. The higher up the better the views.

 

** the f2.8, 8” Boren-Simon scope I use — the NA Nebula is so big that you cannot tell what you are looking at in scope. This is also true for the California, Heart & Soul, Bernie’s Loop in Orion, the nebulosity complex at the other star in Cygnus (near Crescent Nebula) and other nebulous patches - many are just huge and show well at 1x thru 7x in hand held mode.


Edited by Mazerski, 17 September 2019 - 02:30 PM.

  • GOLGO13 likes this

#9 GeezerGazer

GeezerGazer

    Viking 1

  • *****
  • Posts: 969
  • Joined: 06 Jan 2005
  • Loc: Modesto, CA

Posted 17 September 2019 - 07:39 PM

Recommended reading about NV filters including H-a: 

https://www.cloudyni...s-used-with-nv/



#10 GOLGO13

GOLGO13

    Skylab

  • *****
  • topic starter
  • Posts: 4277
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 17 September 2019 - 09:04 PM

Thanks GeezerGazer...looks like there was some debate on this in the past, but it seemed like most people settled on 5nm eventually. A few using 6 or 7.

 

But Eddgie points out in one post that the 12nm works well at 1x in a dark sky where the other ones cut off the field a bit too much for certain objects. 

 

And it sounded like focal ratio plays a small role also.

 

I'm thinking a 12nm maybe worthwhile to have along with the 5nm. Not sure what brands are best for this.



#11 jdbastro

jdbastro

    Viking 1

  • *****
  • Posts: 762
  • Joined: 18 Aug 2007
  • Loc: F'd up Sanctuary State

Posted 18 September 2019 - 12:29 AM

The Astronomik 12nm H-a filter is excellent.  I have several of them.


  • chemisted likes this

#12 Jeff Morgan

Jeff Morgan

    Voyager 1

  • *****
  • Posts: 10986
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 18 September 2019 - 01:14 AM

I have the 7nm and 12nm and like them both very much.

 

A very narrow band pass can put you in situations where the intensifier is starved for photons. This situation is recognized by an excessively dark view, grainy view, or scintillation. You'll especially notice this when you are using multiple optics with different effective focal ratios.

 

Backing off to a more "permissive" filter can often brighten the view, at the cost of somewhat less nebulosity.

 

OTOH, many h-alpha regions have associated star clusters, which are largely snuffed by tight filters. A looser filter gives you more stars for a more balanced appearance.

 

Very nice to have a choice, even if one filter is only lightly used.


  • chemisted and AllanDystrup like this

#13 bobhen

bobhen

    Gemini

  • *****
  • Posts: 3282
  • Joined: 25 Jun 2005

Posted 18 September 2019 - 08:36 AM

I live 8 miles from Philadelphia in absolutely horrendous light pollution. The only location worse would be observing from the center of a large city.

 

I have used the 7 and 6 and like the 6 better. Never used a 12 because it just wouldn’t be strong enough. I have used 610 and 685 Pass filters and just use the 685 now. The views last night were killer using my 4” refractor at F3.5 with both of these filters.

 

With my light pollution, I have to select to observer either nebula or non-nebula objects. No mild filter will allow me to observe both nebulas and star clusters at the same time and deliver an acceptable view of either.

 

I keep telling myself the 6 is plenty good enough (and it really is great) mostly because I don’t want to spend the money for a 5.

 

Bob



#14 Mazerski

Mazerski

    Vostok 1

  • ****-
  • Posts: 198
  • Joined: 13 Nov 2013

Posted 18 September 2019 - 10:02 AM

Last night was unusually clear in MD and due to my time (before moon glow) I used hand held and I keep proving this to be true for my sky conditions

 

== the 642IR provides the best all around view — the MW was fantastic and can see nebulosity for M16, 17, 20 and 8 (and other blotches) using the Mod 3 and PVS7.

 

== with 12nm Ha and PVS7 (White) could see the 3 sections of the Veil as well as nebulous patches in and around Cassiopeia

 

== with 6nm and Mod 3 the Veil is brighter than in the PVS7 (I think this is expected due to tubes)

 

== for me, the 610 let’s too much light in and the 685 (which I like and use) blocks most nebulosity.

 

If clear tonight like last night, I’ll have the 8” f/2.8 scope out with 5 filters in filter wheel to scroll thru with Mod3 and PVS7.



#15 bobhen

bobhen

    Gemini

  • *****
  • Posts: 3282
  • Joined: 25 Jun 2005

Posted 18 September 2019 - 11:24 AM

Last night was unusually clear in MD and due to my time (before moon glow) I used hand held and I keep proving this to be true for my sky conditions

 

== the 642IR provides the best all around view — the MW was fantastic and can see nebulosity for M16, 17, 20 and 8 (and other blotches) using the Mod 3 and PVS7.

 

== with 12nm Ha and PVS7 (White) could see the 3 sections of the Veil as well as nebulous patches in and around Cassiopeia

 

== with 6nm and Mod 3 the Veil is brighter than in the PVS7 (I think this is expected due to tubes)

 

== for me, the 610 let’s too much light in and the 685 (which I like and use) blocks most nebulosity.

 

If clear tonight like last night, I’ll have the 8” f/2.8 scope out with 5 filters in filter wheel to scroll thru with Mod3 and PVS7.

 

Yes last night was a good one up here in Pa as well. And we might get a few more this week.

 

I used the 6 Ha and 685 Pass filters with the 4” refractor working at around F3.5 The scope was riding on a Universal Astronomics alt/az mount: no chair no eyepieces, so a pretty basic and easy set up.

 

These were all observed before moonrise. And many would not be possible or washed out versions of themselves without NV from my location.

 

North American Nebula: KILLER: Detailed edges + Pelican MUCH
Surrounding Nebula! A GREAT View!
More Nebulas than are in my S & T Pocket Atlas!
Y Sadr Complex: KILLER views MUCH surrounding Nebula Including the following: IC-1311, IC-1318, 6914, IC-4996, IC-5068, SH2-112, and more
Sh2-115 North of Deneb
SH2-101 Nebula just over from the Crescent. 2 stars surrounded by nebula
6888 Crescent Nebula: Bright and well-seen, even the faint part of the arc
M8: GREAT photo-like view with dark lanes were well seen and hard edged. The connecting nebula between M20 & M8 was easy!
N6559 & IC-1274, & IC-4681 nebula detached from M8: were easy & well  seen, as individual puffballs.
M20: GREAT view of nebula with “detailed” thin, dark lanes
M17: GREAT view with “photo-like details”, black square & detached nebula Nebula near: M17: Large dim associated patch
M16: Killer view with WIDE Eagle shape
Sh2-53: The large dim cloud nebula above M16 with the bright internal ball
SH2-115
M22: Smallish but still nice in the 4”
M28: Small in the 4”
6642: Very small in the 4”
6638: Very small in the 4”
M7: Great View like a smaller Pleiades
M6: Open cluster near M7
M11: Smallish in the 4”
6712: Globular cluster near M11 smallish in the 4”
Dark Nebula B111: Near M11 BEST VIEW! Easy to see:
Dark Nebula Near Galactic Center: WOW! A GREAT VIEW! of these dark nebulas superimposed over the VERY bright galactic center!
M69 Easily spotted globular cluster Smallish in the 4”
Little Star Cloud: KILLER! & FILLED with stars
Veil Nebula: All 3 sections were easy: the large arc just fit in the field and was detailed with internal streamers: GREAT VIEW!
Cocoon nebula: Found by sweeping with the 4” nice puffball
7538: Bubble Nebula in Cass.
7635: Nebula in Cass. – Obvious
SH2-157: large dimmer glow forms a triangle with the 2 above
281: Low but easy with dark indent
IC 396: Just fits in the field of the 4”

Bob


Edited by bobhen, 18 September 2019 - 12:23 PM.


#16 Mazerski

Mazerski

    Vostok 1

  • ****-
  • Posts: 198
  • Joined: 13 Nov 2013

Posted 18 September 2019 - 12:02 PM

That’s quite a list, thanks for publishing it. Some I don’t recognize but I’ll have the list handy for tonight with 8” and Nexus DSC. Unfortunately my house is now blocking the SE sky in setting up scope on patio... hand held I can walk around.



#17 slavicek

slavicek

    Mariner 2

  • *****
  • Posts: 241
  • Joined: 01 Aug 2017
  • Loc: Massachusetts

Posted 18 September 2019 - 03:49 PM

Thanks GeezerGazer...looks like there was some debate on this in the past, but it seemed like most people settled on 5nm eventually. A few using 6 or 7.

 

But Eddgie points out in one post that the 12nm works well at 1x in a dark sky where the other ones cut off the field a bit too much for certain objects. 

 

 

 

I'm thinking a 12nm maybe worthwhile to have along with the 5nm. Not sure what brands are best for this.

I use Baader, Astronomik and Chroma filters. Judging from different past posts and from my own experience, Chroma is likely the best but also the most expensive - it gets costly, especially in 2 inch dia.



#18 GOLGO13

GOLGO13

    Skylab

  • *****
  • topic starter
  • Posts: 4277
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 01 October 2019 - 10:26 AM

I decided to make my last purchase for a long time frame (have to tighten up spending for a bit). I purchased the Chroma 8nm to pair with my 5nm Astrodon. 

 

I researched historical night vision posts on here and it appears that it helps to have a bit of both less and more HA options. Depending on the object, the telescope, the focal ratio, etc. I really want to try out my 8 inch SCT on some smaller objects and brighter objects.

 

I do think a filter wheel is in my future for the 6 inch newt, but I'll just manually do it for now. It really doesn't bother me, but sure a wheel would be more convenient. 

 

Yesterday it was really humid and hot and NV seemed to suffer quite a bit because of that. 

 

I'm also interested in seeing if the 8nm will not cut off/out so much with the 1x observing. The 5nm really chops off quickly.



#19 Mark Strollo

Mark Strollo

    Explorer 1

  • *****
  • Posts: 73
  • Joined: 20 Mar 2006
  • Loc: Waterford, CT

Posted 10 October 2019 - 12:36 PM

I'm also about to purchase the 2" Chroma 8nm since I'm headed to the southwest for a week of observing.  Anybody have them in stock?



#20 GOLGO13

GOLGO13

    Skylab

  • *****
  • topic starter
  • Posts: 4277
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 10 October 2019 - 01:48 PM

I got it from optcorp.com. not sure if they do or not

#21 slavicek

slavicek

    Mariner 2

  • *****
  • Posts: 241
  • Joined: 01 Aug 2017
  • Loc: Massachusetts

Posted 10 October 2019 - 11:39 PM

I decided to make my last purchase for a long time frame (have to tighten up spending for a bit). I purchased the Chroma 8nm to pair with my 5nm Astrodon. 

 

I researched historical night vision posts on here and it appears that it helps to have a bit of both less and more HA options. Depending on the object, the telescope, the focal ratio, etc. I really want to try out my 8 inch SCT on some smaller objects and brighter objects.

 

 

 

I'm also interested in seeing if the 8nm will not cut off/out so much with the 1x observing. The 5nm really chops off quickly.

Also, I chose the filter bandwidth based on how bad the sky pollution is at the place where I observe. Narrower filter for polluted sky is the basic rule of thumb.

Good luck with "not spending any more money" - I've tried that too...



#22 GOLGO13

GOLGO13

    Skylab

  • *****
  • topic starter
  • Posts: 4277
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 11 October 2019 - 06:05 AM

Hah...yeah. ive already thrown the not getting more stuff out the window. However, I sold some items. I'm guessing a lot of people who get into night vision make some drastic changes with their equipment. I may try the 6nm astronomik...the chroma 5nm seems a bit too much money. I think I will also get a 12nm to have some options.

#23 Mike Lockwood

Mike Lockwood

    Vendor, Lockwood Custom Optics

  • *****
  • Vendors
  • Posts: 1582
  • Joined: 01 Oct 2007
  • Loc: Usually in my optical shop

Posted 11 October 2019 - 11:31 AM

See the link in my thread for my comparison of the 7nm Baader and 6nm Astronomik - the Baader performed very well and costs less.



#24 GOLGO13

GOLGO13

    Skylab

  • *****
  • topic starter
  • Posts: 4277
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 11 October 2019 - 11:42 AM

I think since I have the 8nm Chroma I'll try the 6nm Astronomik...then maybe later try the 5nm chroma. The baader 7 maybe too close to my chroma.

 

I can say the difference between the 8nm chroma and the 5nm astrondon was significant in my mod 3. So I'm not exactly sure why. It doesn't appear anything is wrong with the filter or the mod 3. Based on reading a ton of cloudynight posts on HA filters, I think it's not cut and dry and I suspect tube specs or amount of light pollution could be potential reasons. 

 

I ordered the 12nm and 6nm Astronomik and will do some comparisons. The 12 I got just to have some options and for dark sky situations. I'm the type who likes to have options when it comes to filters and eyepieces etc.

 

I wanted to try the 5nm Chroma, but it's just too expensive to take a gamble on. Maybe sometime in the future. Would like to try it out first since the astrodon that should be similar didn't do well with my equipment.



#25 Gavster

Gavster

    Viking 1

  • -----
  • Posts: 666
  • Joined: 07 Mar 2014

Posted 11 October 2019 - 12:39 PM

I think since I have the 8nm Chroma I'll try the 6nm Astronomik...then maybe later try the 5nm chroma. The baader 7 maybe too close to my chroma.

 

I can say the difference between the 8nm chroma and the 5nm astrondon was significant in my mod 3. So I'm not exactly sure why. It doesn't appear anything is wrong with the filter or the mod 3. Based on reading a ton of cloudynight posts on HA filters, I think it's not cut and dry and I suspect tube specs or amount of light pollution could be potential reasons. 

 

I ordered the 12nm and 6nm Astronomik and will do some comparisons. The 12 I got just to have some options and for dark sky situations. I'm the type who likes to have options when it comes to filters and eyepieces etc.

 

I wanted to try the 5nm Chroma, but it's just too expensive to take a gamble on. Maybe sometime in the future. Would like to try it out first since the astrodon that should be similar didn't do well with my equipment.

This thread has my side by side comparison of the chroma 5nm vs the astrodon 5nm

https://www.cloudyni...ronomik-6nm-ha/




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics