OIII filter question

[tripleped]

I've  had  some  success  recently  observing the  Lagoon, Omega, and  Trifid  nebulae (all for the first  time)  with my 10" dob under  bortle  6 skies.  Would  an Olll filter help much under  those conditions  or  does  it really take  darker skies to get any significant  benefit  from this  type of filter? There  is  a bortle  4 site  that my local astronomy club makes  a monthly trip to but I  haven't been there yet. ( but plan to soon)  I would assume  under bortle  4  the benefit would be significant for those targets?

[jetstream]

1 hour ago, tripleped said:

I've  had  some  success  recently  observing the  Lagoon, Omega, and  Trifid  nebulae (all for the first  time)  with my 10" dob under  bortle  6 skies. 

You saw these no filter, vg- how dark is your sky described as Bortle 6? NELM or SQM any idea?

[tripleped]

Admit I’m not familiar with those.  Clear Outside says 19.23 for magnitude. I can tell you that Milky Way is obvious, not terribly bright or dense but obvious even going pretty low towards horizon.  Now I’m seeing a fraction of the overall nebulosity on these but at least it’s there, took some more dedicated observing to see it on  Trifid but definitely there.  And have never seen them under bottle 8 so to me they were “popping out”. 

[jetstream]

15 hours ago, tripleped said:

Admit I’m not familiar with those.  Clear Outside says 19.23 for magnitude. I can tell you that Milky Way is obvious, not terribly bright or dense but obvious even going pretty low towards horizon.  Now I’m seeing a fraction of the overall nebulosity on these but at least it’s there, took some more dedicated observing to see it on  Trifid but definitely there.  And have never seen them under bottle 8 so to me they were “popping out”. 

I'm thinking your darker than "Bortle 6 " suggests. OIII filters work well espc when you can see the objects unfiltered and there is no better filter for the Veil than a top OIII IMHO.

[globular]

What sort of exit pupil do you find works best with OIII filter @jetstream?  Or don't you think it matters?
I find over 2mm exit pupil is 'needed'.... and the larger the better.....
But with more light polluted skies the views get washed out with larger exit pupils.... particularly >3.5mm
The OIII does help to darken the sky (given it's cutting out all but the intended light bands)....
But I find it only seems to work "well" on the few very dark nights I get in my garden.

 

Edited September 2, 2021 by globular

[tripleped]

okay thanks jetstream.  So I think I will try to find  a filter  for  the veil before  my dark sky outing  next month.  Others have recommended  either  Astronomik or  Lumicon as  far as  OIII is concerned advising  to  "not go cheap"  With that  in mind  what  would be a rough pricepoint to look for to get  something of  respectable performance?

[Kon]

Based on @jetstream and others suggestion on this forum, i bought this one:

https://www.firstlightoptics.com/televue-filters/tele-vue-bandmate-oiii-filter.html

yes it is pricy but once you see the Veil, North America, Pacman and many more it makes up its money; Veil alone was sufficient for me to justify its price. I am at bortle 3/4 skies using an 8" Dob. Have a look at some of the observing reports I have done using OIII and which other targets have benefitted.

Several discussions on OIII if you have a search at the forums.

 

[John]

3 minutes ago, Kon said:

Based on @jetstream and others suggestion on this forum, i bought this one:

https://www.firstlightoptics.com/televue-filters/tele-vue-bandmate-oiii-filter.html

yes it is pricy but once you see the Veil, North America, Pacman and many more it makes up its money; Veil alone was sufficient for me to justify its price. I am at bortle 3/4 skies using an 8" Dob. Have a look at some of the observing reports I have done using OIII and which other targets have benefitted.

Several discussions on OIII if you have a search at the forums.

 

Yep, that's what I would get if buying from scratch again.

Important to get the Bandmate Type 2 though. The Type 1's are still out there but are not as effective. Tele Vue switched manufacturer and spec for the Type 2 and that has really paid off.

 

[globular]

I got the Astronomik one as the bandmate was not available at the time (and I was impatient).  I understand they are the same filter, both made by Astronomik, but Tele View test them themselves for compliance with the stated specifications before accepting them, so you are less likely to get a dud one.  (Not that the Astronomik ones are riddle with duds... )

[tripleped]

Ok,  thanks  to all for the advice,  thats very helpful!  

[Deadlake]

9 minutes ago, globular said:

I got the Astronomik one as the bandmate was not available at the time (and I was impatient).  I understand they are the same filter, both made by Astronomik, but Tele View test them themselves for compliance with the stated specifications before accepting them, so you are less likely to get a dud one.  (Not that the Astronomik ones are riddle with duds... )

Me too, however Tele Vue band mate blocks additional part of the red spectrum. Reading some more, some times you want this sometimes you do no. Usual answer you end up with both... 😀

[globular]

1 minute ago, Deadlake said:

Me too, however Tele Vue band mate blocks additional part of the red spectrum. Reading some more, some times you want this sometimes you do no. Usual answer you end up with both... 😀

Dusts off credit card....

[JTEC]

10 minutes ago, John said:

Yep, that's what I would get if buying from scratch again.

Important to get the Bandmate Type 2 though. The Type 1's are still out there but are not as effective. Tele Vue switched manufacturer and spec for the Type 2 and that has really paid off.

Me too.   FWIW, I’ve tried most of the contenders over the years and have settled on the Televue Bandmate OIII.  If there’s such a thing as a ‘best’ such filter, it would be my suggestion.  Just to muddy the ‘UHC’ waters a little, you might like to spare a thought for the Omega/DGM NPB filter, which, along with many other observers, I like a lot.

[jetstream]

1 hour ago, globular said:

What sort of exit pupil do you find works best with OIII filter @jetstream?  Or don't you think it matters?
I find over 2mm exit pupil is 'needed'.... and the larger the better.....
But with more light polluted skies the views get washed out with larger exit pupils.... particularly >3.5mm
The OIII does help to darken the sky (given it's cutting out all but the intended light bands)....
But I find it only seems to work "well" on the few very dark nights I get in my garden.

 

I've played around extensively with exit pupils and filters. Exit pupil definitely matters IMHO.Yes 2mm is very small for OIII's- I like 4mm-6mm . As an example I used a 30mm ES 82 @ f4.8 the other night for a 6.25mm exit pupil on the NAN for those 2 features. The 20mm APM 100 was also used at 4.2mm with good effect.

From dark skies a 4mmish exit pupil works great on the Veil - but- I find aperture matters and not for the commonly thought reason.

A large scope with a long fl needs less "help" bringing out features as the mag is already high enough. A small scope can take a bit more mag with the filters- a trade off will be found between exit pupil and the needed mag. The darker the skies only lead to greater enhancement regardless.

 

Edited September 2, 2021 by jetstream

[jetstream]

1 hour ago, globular said:

But with more light polluted skies the views get washed out with larger exit pupils.... particularly >3.5mm

The view is washed out with the OIII?

[jetstream]

1 hour ago, globular said:

(Not that the Astronomik ones are riddle with duds... )

No worries there thats for sure- Astronomiks are vg and tightened up there bandwidth a few years ago.

[jetstream]

1 hour ago, tripleped said:

With that  in mind  what  would be a rough pricepoint to look for to get  something of  respectable performance?

Being in the USA go for the new Televue OIII- its my best OIII ( I have 3), not sure what they go for, I paid a couple hundred bucks from Astrosystems and he confirmed the specs for me. That extra test was not needed however as all these new TV filters are vg. $200 for a 2", expensive but worth it IMHO.

Ive been ripped off before on filters...

[globular]

41 minutes ago, JTEC said:

Me too.   FWIW, I’ve tried most of the contenders over the years and have settled on the Televue Bandmate OIII.  If there’s such a thing as a ‘best’ such filter, it would be my suggestion.  Just to muddy the ‘UHC’ waters a little, you might like to spare a thought for the Omega/DGM NPB filter, which, along with many other observers, I like a lot.

+1 for the DGM NPB... I love it.

[globular]

15 minutes ago, jetstream said:

The view is washed out with the OIII?

No.  Just the skies generally with large exit pupils in less than ideal conditions (and my telescope).
It's really a combination of exit pupil and magnification.... as you were saying above.... but unless you have lots of scopes to choose from you don't get to change one without the other.
I will get another scope that is better at these things eventually.... once I've run out of good stuff to point this one at  

 

[jetstream]

5 minutes ago, globular said:

+1 for the DGM NPB... I love it.

Me too- it shows the Flaming Star in Auriga using the H130/24 ES 68 -a piece of cake. Dan McShane is a vg guy IMHO. Our DGM NPB is really good, very tight, good transmission.

[jetstream]

Just now, globular said:

No.  Just the skies generally with large exit pupils in less than ideal conditions (and my telescope).
It's really a combination of exit pupil and magnification.... as you were saying above.... but unless you have lots of scopes to choose from you don't get to change one without the other.
I will get another scope that is better at these things eventually.... once I've run out of good stuff to point this one at  

 

The C8 is regarded to be a fantastic all round scope, including neb observation. YKSE uses one with fantastic results.

[globular]

Just now, jetstream said:

The C8 is regarded to be a fantastic all round scope, including neb observation. YKSE uses one with fantastic results.

No arguments from me

I'm not knocking my scope.... I know people can get a little 'deluded' that they have 'the best example' of their telescope.... and I'm no different.... I think I have one of the better ones knocking around  

[Deadlake]

27 minutes ago, globular said:

No arguments from me

I'm not knocking my scope.... I know people can get a little 'deluded' that they have 'the best example' of their telescope.... and I'm no different.... I think I have one of the better ones knocking around  

Why the EDGE over a stock C8. Ability to add fans to cool down or not really an issue?

[Stu]

1 hour ago, Deadlake said:

Why the EDGE over a stock C8. Ability to add fans to cool down or not really an issue?

Didn’t see any mention of the Edge, but I found my C8 Edge excellent with widefield eyepieces. I think the Edge optics flatten the field and give better stars. Most people think they are only really of benefit for imaging, but they also perform better for observing to my eyes.

The Edge optics do block the baffle tube so if anything they cool slower than a standard SCT. The aftermarket vent fans are potentially needed because of this.

[Deadlake]

45 minutes ago, Stu said:

Didn’t see any mention of the Edge, but I found my C8 Edge excellent with widefield eyepieces. I think the Edge optics flatten the field and give better stars. Most people think they are only really of benefit for imaging, but they also perform better for observing to my eyes.

The Edge optics do block the baffle tube so if anything they cool slower than a standard SCT. The aftermarket vent fans are potentially needed because of this.

From  globulars equipment list:
8" EdgeHD Aplanatic Schmidt-Cassegrain F/10.6 | ~20.4 mag/arcsec