Is it worth getting another visual filter?

[RobertI]

Just an update to this rather old thread for posterity. I ended up purchasing a Hb filter but only recently got round to trying it out. Using my 4” apo and a 32mm plossl, I had a go at the California nebula in Perseus. I was not really expecting to see anything but was really surprised to pick it up straight away - it was large and dim, but immediate and unmistakeable. I also tried with a UHC, OIII and no filter, but the nebula was completely invisible. Back to the Hb and it popped into view again. It was worth the purchase just to see the California neb to be honest, as I’d never managed it before. Looking forward to trying the elusive Horsehead over the winter, possibly with the C8. There appear to be a few other more obscure “Hb friendly” nebulae which I’ll also have a go at some time.

[Don Pensack]

Pure H-ß objects:

1. IC 434 w/B33(HORSEHEAD NEBULA)
2. NGC 1499 (CALIFORNIA NEBULA, naked eye and RFT)
3. M43 (part of the Great Orion Nebula)
4. IC 5146 (COCOON NEBULA in Cygnus)
5. M20 (TRIFID NEBULA, main section)
6. NGC 2327 (diffuse nebula in Monoceros)
7. IC 405 (the FLAMING STAR NEBULA in Auriga)
8. IC 417 (diffuse Nebula in Auriga)
9. IC 1283 (diffuse Nebula in Sagittarius)
10. IC 1318 GAMMA CYGNI NEBULA (diffuse nebula in Cygnus)
11. IC 2177: SEAGULL NEBULA (Diffuse Nebula, Monoceros)
12. IC 5076 (diffuse nebula, Cygnus)
13. PK64+5.1 "CAMPBELL'S HYDROGEN STAR" Cygnus (PNG 64.7+5.0)
14. Sh2-157a (small round nebula inside larger Sh2-157, Cassiopeia)
15. Sh2-235 (diffuse nebula in Auriga).
16. Sh2-276 "BARNARD'S LOOP" (diffuse nebula in Orion, naked eye)
17. IC 2162 (diffuse nebula in northern Orion)
18 Sh2-254 (diffuse nebula in northern Orion near IC 2162)
19. Sh2-256-7 (diffuse nebula in northern Orion near IC 2162)
20. vdB93 (Gum-1) (diffuse nebula in Monoceros near IC 2177)
21. Lambda Orionis nebular complex (very large, naked-eye)
22. Sh2-273 "Cone" Nebula portion south of cluster NGC 2264

[John]

I owned an H-Beta filter for a few years (an Astronomik) but with the exception of the Horsehead Nebula, I struggled to see much with it, despite the list that Don gives above and including use with my 12 inch dobsonian.

The Horsehead was very, very indistinct even with the 12 inches of aperture. I saw it on 3 occasions over a period of around 5 years - nights when I had the darkest and most transparent skies that I get here.

I don't own the filter now. I am glad that I owned one for a while though, if only because the Horsehead is such an iconic target.

Maybe I'm an "outlier" in this experience though 🤔

Edited August 29, 2023 by John

[RobertI]

1 hour ago, Don Pensack said:

Pure H-ß objects:

1. IC 434 w/B33(HORSEHEAD NEBULA)
2. NGC 1499 (CALIFORNIA NEBULA, naked eye and RFT)
3. M43 (part of the Great Orion Nebula)
4. IC 5146 (COCOON NEBULA in Cygnus)
5. M20 (TRIFID NEBULA, main section)
6. NGC 2327 (diffuse nebula in Monoceros)
7. IC 405 (the FLAMING STAR NEBULA in Auriga)
8. IC 417 (diffuse Nebula in Auriga)
9. IC 1283 (diffuse Nebula in Sagittarius)
10. IC 1318 GAMMA CYGNI NEBULA (diffuse nebula in Cygnus)
11. IC 2177: SEAGULL NEBULA (Diffuse Nebula, Monoceros)
12. IC 5076 (diffuse nebula, Cygnus)
13. PK64+5.1 "CAMPBELL'S HYDROGEN STAR" Cygnus (PNG 64.7+5.0)
14. Sh2-157a (small round nebula inside larger Sh2-157, Cassiopeia)
15. Sh2-235 (diffuse nebula in Auriga).
16. Sh2-276 "BARNARD'S LOOP" (diffuse nebula in Orion, naked eye)
17. IC 2162 (diffuse nebula in northern Orion)
18 Sh2-254 (diffuse nebula in northern Orion near IC 2162)
19. Sh2-256-7 (diffuse nebula in northern Orion near IC 2162)
20. vdB93 (Gum-1) (diffuse nebula in Monoceros near IC 2177)
21. Lambda Orionis nebular complex (very large, naked-eye)
22. Sh2-273 "Cone" Nebula portion south of cluster NGC 2264

Thanks Don, great list I’ll give some of these a go.

[RobertI]

51 minutes ago, John said:

I owned an H-Beta filter for a few years (an Astronomik) but with the exception of the Horsehead Nebula, I struggled to see much with it, despite the list that Don gives above and including use with my 12 inch dobsonian.

The Horsehead was very, very indistinct even with the 12 inches of aperture. I saw it on 3 occasions over a period of around 5 years - nights when I had the darkest and most transparent skies that I get here.

I don't own the filter now. I am glad that I owned one for a while though, if only because the Horsehead is such an iconic target.

Maybe I'm an "outlier" in this experience though 🤔

I’ll let you know how I get on John! I’m not really expecting to have much luck with the Horsehead tbh. 

[bomberbaz]

With John here in the main, the filter has limited use. I have the identical list to what Don posted but I have either struggled or not needed the Hb filer with them.

EDIT; The key to nearly all HB targets is very dark skies, moving on.

This is my opinion and not fact btw. Where no comment, I have not yet got around to trying with an HB. I used a 14" F5 dob and eyepiece giving a 5mm exit pupil:

1. IC 434 w/B33(HORSEHEAD NEBULA)   Absolutly needed
2. NGC 1499 (CALIFORNIA NEBULA, naked eye and RFT) UHC also works, not a huge difference between the 2
3. M43 (part of the Great Orion Nebula)  Need to try this again so no comment
4. IC 5146 (COCOON NEBULA in Cygnus) difficult, I wasn't sure if I saw.
5. M20 (TRIFID NEBULA, main section) 
6. NGC 2327 (diffuse nebula in Monoceros) 
7. IC 405 (the FLAMING STAR NEBULA in Auriga) UHC works fine for me
8. IC 417 (diffuse Nebula in Auriga) 
9. IC 1283 (diffuse Nebula in Sagittarius) 
10. IC 1318 GAMMA CYGNI NEBULA (diffuse nebula in Cygnus)
11. IC 2177: SEAGULL NEBULA (Diffuse Nebula, Monoceros) 
12. IC 5076 (diffuse nebula, Cygnus)
13. PK64+5.1 "CAMPBELL'S HYDROGEN STAR" Cygnus (PNG 64.7+5.0)  Superb with the HB, jumps right out at you. Very difficult without a filter. Not tried a UHC though, suspect it will do well on it.
14. Sh2-157a (small round nebula inside larger Sh2-157, Cassiopeia)
15. Sh2-235 (diffuse nebula in Auriga).
16. Sh2-276 "BARNARD'S LOOP" (diffuse nebula in Orion, naked eye)
17. IC 2162 (diffuse nebula in northern Orion)
18 Sh2-254 (diffuse nebula in northern Orion near IC 2162)
19. Sh2-256-7 (diffuse nebula in northern Orion near IC 2162)
20. vdB93 (Gum-1) (diffuse nebula in Monoceros near IC 2177)
21. Lambda Orionis nebular complex (very large, naked-eye)
22. Sh2-273 "Cone" Nebula portion south of cluster NGC 2264

The objects that respond are limited and the objects that only respond to HB are even more limited. 

You will get a better response using equipment which gives a large exit pupil at 5mm or close too that, these are very tight band pass filters and you need to let a lot of light hit your retina. I think a slow (F6 or slower) will struggle on nearly all of those objects but I would be interested to hear how you get on. 

Dispite all my perceived limitation of the HB filter, I won't get rid of it.

Steve

Edited August 29, 2023 by bomberbaz

[RobertI]

32 minutes ago, bomberbaz said:

With John here in the main, the filter has limited use. I have the identical list to what Don posted but I have either struggled or not needed the Hb filer with them.

EDIT; The key to nearly all HB targets is very dark skies, moving on.

This is my opinion and not fact btw. Where no comment, I have not yet got around to trying with an HB. I used a 14" F5 dob and eyepiece giving a 5mm exit pupil:

1. IC 434 w/B33(HORSEHEAD NEBULA)   Absolutly needed
2. NGC 1499 (CALIFORNIA NEBULA, naked eye and RFT) UHC also works, not a huge difference between the 2
3. M43 (part of the Great Orion Nebula)  Need to try this again so no comment
4. IC 5146 (COCOON NEBULA in Cygnus) difficult, I wasn't sure if I saw.
5. M20 (TRIFID NEBULA, main section) 
6. NGC 2327 (diffuse nebula in Monoceros) 
7. IC 405 (the FLAMING STAR NEBULA in Auriga) UHC works fine for me
8. IC 417 (diffuse Nebula in Auriga) 
9. IC 1283 (diffuse Nebula in Sagittarius) 
10. IC 1318 GAMMA CYGNI NEBULA (diffuse nebula in Cygnus)
11. IC 2177: SEAGULL NEBULA (Diffuse Nebula, Monoceros) 
12. IC 5076 (diffuse nebula, Cygnus)
13. PK64+5.1 "CAMPBELL'S HYDROGEN STAR" Cygnus (PNG 64.7+5.0)  Superb with the HB, jumps right out at you. Very difficult without a filter. Not tried a UHC though, suspect it will do well on it.
14. Sh2-157a (small round nebula inside larger Sh2-157, Cassiopeia)
15. Sh2-235 (diffuse nebula in Auriga).
16. Sh2-276 "BARNARD'S LOOP" (diffuse nebula in Orion, naked eye)
17. IC 2162 (diffuse nebula in northern Orion)
18 Sh2-254 (diffuse nebula in northern Orion near IC 2162)
19. Sh2-256-7 (diffuse nebula in northern Orion near IC 2162)
20. vdB93 (Gum-1) (diffuse nebula in Monoceros near IC 2177)
21. Lambda Orionis nebular complex (very large, naked-eye)
22. Sh2-273 "Cone" Nebula portion south of cluster NGC 2264

The objects that respond are limited and the objects that only respond to HB are even more limited. 

You will get a better response using equipment which gives a large exit pupil at 5mm or close too that, these are very tight band pass filters and you need to let a lot of light hit your retina. I think a slow (F6 or slower) will struggle on nearly all of those objects but I would be interested to hear how you get on. 

Dispite all my perceived limitation of the HB filter, I won't get rid of it.

Steve

Interesting additional comments on these object Steve. I can only comment on the California neb so far using my 102ED and a 32mm Plossl giving an exit pupil of 4.6mm - the nebula was clearly visible but dim with the Hb, but when I tried with an OIII or UHC or no filter I couldn’t see it at all. I’ll definitely try some of these others as I am curious now, but I suspect I started with the best nebula of the bunch. 

[bomberbaz]

10 minutes ago, RobertI said:

Interesting additional comments on these object Steve. I can only comment on the California neb so far using my 102ED and a 32mm Plossl giving an exit pupil of 4.6mm - the nebula was clearly visible but dim with the Hb, but when I tried with an OIII or UHC or no filter I couldn’t see it at all. I’ll definitely try some of these others as I am curious now, but I suspect I started with the best nebula of the bunch. 

try campbells H star Rob, it's an interesting object although as it is a planetary nebula, it is concentrated so bound to be brighter. Would be interested how it responds to higher power, say around x120/180 ish in your apo.

I do think your c8 with a focal reducer is your best bet. 

Edited August 29, 2023 by bomberbaz

[John]

I did find observing Messier 42 interesting with the H-Beta filter. It seemed to enhance the contrast of some of the features surrounding the central region of the nebula although at the expense of the extension visible in the outer tendrils. In particular the "cliff" (image below) near the dark "fish's mouth" feature became noticeably more obvious:

 

Edited August 30, 2023 by John

[RobertI]

8 hours ago, John said:

I did find observing Messier 42 interesting with the H-Beta filter. It seemed to enhance the contrast of some of the features surrounding the central region of the nebula although at the expense of the extension visible in the outer tendrils. In particular the "cliff" (image below) near the dark "fish's mouth" feature became noticeably more obvious:

 

Interesting John, I have switched between OIII, UHC and no filter on M42 and it is equally interesting to see the difference - switching in the Hb should be really interesting. The filter wheel is great for this, makes switching easy and the difference views immediately obvious. 

[bomberbaz]

8 hours ago, John said:

I did find observing Messier 42 interesting with the H-Beta filter. It seemed to enhance the contrast of some of the features surrounding the central region of the nebula although at the expense of the extension visible in the outer tendrils. In particular the "cliff" (image below) near the dark "fish's mouth" feature became noticeably more obvious:

 

Yes I really must try varying my nebula observing methods a little to get a little more out of my sessions. The Orion nebula responds well to HB, OIII & UHC at high power. I would wager a decent sketcher would be able to bring all those elements together really well.

[bomberbaz]

12 hours ago, RobertI said:

I ended up purchasing a Hb filter but only recently got round to trying it out. Using my 4” apo and a 32mm plossl, I had a go at the California nebula in Perseus. 

Rob, what brand of HB filter did you get and do you have a 40mm plossl? The 40mm should give you a stronger response.

Also I notice you have the heritage 130, now an interesting comparison there would be that shooting off against the 4" apo with the HB filter. 

[RobertI]

5 minutes ago, bomberbaz said:

Rob, what brand of HB filter did you get and do you have a 40mm plossl? The 40mm should give you a stronger response.

Also I notice you have the heritage 130, now an interesting comparison there would be that shooting off against the 4" apo with the HB filter. 

It’s an Astronomik Hb, same as my other filters. Yes I do have 40mm Plossl which came with my C8 purchased 25 years ago - it’s still rolling around my eyepiece tray somewhere, never really used, so it will be good to find a use for it! I shall definitely give is a go, good suggestion, although I hope my pupil can expand large enough (5.7mm so should be ok I think). As for the Heritage 130, another good idea, I was thinking about that, it has worked really well with the OIII in the past so will give a go. 👍

[bomberbaz]

1 hour ago, RobertI said:

It’s an Astronomik Hb, same as my other filters. Yes I do have 40mm Plossl which came with my C8 purchased 25 years ago - it’s still rolling around my eyepiece tray somewhere, never really used, so it will be good to find a use for it! I shall definitely give is a go, good suggestion, although I hope my pupil can expand large enough (5.7mm so should be ok I think). As for the Heritage 130, another good idea, I was thinking about that, it has worked really well with the OIII in the past so will give a go. 👍

Great filter and seems you adopt the same approach as me, get the best.

My largest exit pupil from eyepiece is 5.6mm, I won't go any higher than that.  Your heritage should be ok with a 25mm plossl or similar.

I did some comparisons a year or so back using eyepiece sizes up and down from a 5mm exit pupil, even small differences make a fairly significant change in surface area. Smaller didn't help, larger was better but 5mm seemed to be a safe bet to recommend as optimum size exit pupil.

A good dso to test this out on with your scopes, assuming you see it at all is the crescent. Let us know how you get on won't you.

Steve

[Louis D]

If you have a long eye relief, low power eyepiece, try the blinking technique with the filter between your eye and the eyepiece.  This is how I've been comparing filters for false color reduction on achromats.  It's easier to see subtle differences between filters when you rapidly move them in and out of the exit pupil.  You can even try stacking filters this way to see if one is more dominant than another.  For instance, an HB or OIII should look the same with a UHC stacked ahead of it since the UHC should typically be passing both HB and OIII.

[Don Pensack]

45 minutes ago, Louis D said:

If you have a long eye relief, low power eyepiece, try the blinking technique with the filter between your eye and the eyepiece.  This is how I've been comparing filters for false color reduction on achromats.  It's easier to see subtle differences between filters when you rapidly move them in and out of the exit pupil.  You can even try stacking filters this way to see if one is more dominant than another.  For instance, an HB or OIII should look the same with a UHC stacked ahead of it since the UHC should typically be passing both HB and OIII.

I've used the blinking technique on planetary nebulae that are so small they are little different than star images at low powers.

The nebula stays visible when almost all the stars disappear or get seriously darkened.

But for fainter objects, the difficult with this technique is that the filter is essentially a mirror and reflects back so much ambient light the objects become invisible.

[RobertI]

3 hours ago, Louis D said:

If you have a long eye relief, low power eyepiece, try the blinking technique with the filter between your eye and the eyepiece.  This is how I've been comparing filters for false color reduction on achromats.  It's easier to see subtle differences between filters when you rapidly move them in and out of the exit pupil.  You can even try stacking filters this way to see if one is more dominant than another.  For instance, an HB or OIII should look the same with a UHC stacked ahead of it since the UHC should typically be passing both HB and OIII.

 

2 hours ago, Don Pensack said:

I've used the blinking technique on planetary nebulae that are so small they are little different than star images at low powers.

The nebula stays visible when almost all the stars disappear or get seriously darkened.

But for fainter objects, the difficult with this technique is that the filter is essentially a mirror and reflects back so much ambient light the objects become invisible.

Thanks for the thoughts Louis and Don. My filters live in a manual filter wheel at the moment, so I can flick between them quickly, although obviously I can’t stack! 

[Louis D]

2 hours ago, Don Pensack said:

But for fainter objects, the difficult with this technique is that the filter is essentially a mirror and reflects back so much ambient light the objects become invisible.

You are correct.  I was thinking about that when I wrote that.  However, I still found it effective to confirm comet ZTF using that off-spec Zhumell OIII filter.  It was the only part of the sky that didn't dim.  When attached to the eyepiece, it wasn't as effective because the blinking response wasn't activated in my brain.  I could sort of detect it by sweeping past its position in that case.  It's similar to how I can't see a camouflaged animal until it moves, then it's obvious.

[RobertI]

If folk are interested I have created a Sky Safari observing list with Don’s Hb targets (except three I couldn’t find), hope it’s of use….

H Beta targets.skylist

[bomberbaz]

15 hours ago, RobertI said:

If folk are interested I have created a Sky Safari observing list with Don’s Hb targets (except three I couldn’t find), hope it’s of use….

H Beta targets.skylist 2.82 kB · 4 downloads

No campbell's H star rob? 

ignore me, I have seen it

 

Edited August 31, 2023 by bomberbaz

[RobertI]

4 hours ago, bomberbaz said:

No campbell's H star rob? 

ignore me, I have seen it

 

I’ve just seen that there’s already an H-Beta SkySafari list in the Member’s observing list thread! Oh well….