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John

New Range of Tele Vue Filters

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4 minutes ago, John said:

I would not have thought that the switch to a 25mm TV plossl to a 24mm Panoptic would have made much / any difference to how the O-III performed ?

While the AFoV is larger with the Panoptic, the overall performance, light transmission etc is pretty much thye same with the 25mm TV plossl I think. With regards to light transmission the plossl is probably a touch better than the Panoptic (TV plossls are some of the best there is for light transmission).

Exit pupil does make a difference to the performance of narrowband and line filters but the focal length of the eyepiece determines that, not the AFoV.

The Veil is a large target (a bit over 3 degrees for the whole complex, each of the brightest arcs are approx 1.3 degrees in extent) so a wide true field is required.

 

 

I am pretty sure I had a set of Deloi at the time so it is possible I overdid it with magnification as the 17.3mm is the lowest power, I also had the 31mm Nagler at the time, could this have been the problem?

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1 minute ago, Pig said:

That’s interesting ..... maybe I over egged the magnification.

Yes, certainly with the large faint objects, keeping the exit pupil up at 4 or 5mm will help maintain the brightness through the filter. Brighter ones like M42 or M57 will cope with higher power, but the Veil is very faint.

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Just now, Pig said:

I am pretty sure I had a set of Deloi at the time so it is possible I overdid it with magnification as the 17.3mm is the lowest power, I also had the 31mm Nagler at the time, could this have been the problem?

I would certainly have gone for the Nag over the Delos in this instance

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With my 12" dob and the 21mm Ethos + Lumicon O-III filter from my back garden, David Knisely's impression with a 10 inch scope under darker skies is pretty much the impact that the O-III has, if anything from my garden the unfiltered view is fainter and the filtered one, more contrasty.

OIIIfilterVeilSlide800x600.jpg.33a0ebf855923c169a077e3010163f4f.jpg

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7 minutes ago, John said:

I would not have thought that the switch to a 25mm TV plossl to a 24mm Panoptic would have made much / any difference to how the O-III performed ?

While the AFoV is larger with the Panoptic, the overall performance, light transmission etc is pretty much thye same with the 25mm TV plossl I think. With regards to light transmission the plossl is probably a touch better than the Panoptic (TV plossls are some of the best there is for light transmission).

Exit pupil does make a difference to the performance of narrowband and line filters but the focal length of the eyepiece determines that, not the AFoV.

The Veil is a large target (a bit over 3 degrees for the whole complex, each of the brightest arcs are approx 1.3 degrees in extent) so a wide true field is required.

 

 

I would agree with this John, surprised there was so much difference. The exit pupil is similar, fov only a little larger in the Panoptic and the Plossls have a good reputation for light transmission. Strange one.

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Ok I will try again..... will a 1.25 format be ok ?

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You do require dark skies, dark adaption, a good quality filter and as mentioned, except for planetary nebula, the applicable exit pupil at low power. I have observed the California nebula with a H-beta and 76mm refractor - nothing is improbable in dark skies.

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3 minutes ago, Stu said:

I would agree with this John, surprised there was so much difference. The exit pupil is similar, fov only a little larger in the Panoptic and the Plossls have a good reputation for light transmission. Strange one.

Thanks for comments John & Stu, will do another comparison check next clear night. 

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20 minutes ago, Pig said:

Ok I will try again..... will a 1.25 format be ok ?

Do you have a 32mm plossl? With a 24mm 68 degree you are at 3.2mm exit pupil, vs 4.3mm in a 32mm plossl. This is one of those cases where, although the 32mm doesn’t gain you much in true field of view, it does help with filtered views due to the larger exit pupil. Of course something like a 2” 42mm Vixen would give you 5.6mm which is even better but try the plossl first.

Larger exit pupils can count against you under light polluted skies, giving poorer contrast, but with narrowband filters and preferable darker skies, a larger exit pupil really helps pull out the fainter nebulae.

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14 minutes ago, jock1958 said:

Thanks for comments John & Stu, will do another comparison check next clear night. 

Let us know how you get on Jock. Which scope do you have and which objects did you try? It may have been that the relatively small fov increase just allowed you to see the edges of the object and gave you the contrast to see it?

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Just now, Stu said:

Do you have a 32mm plossl? With a 24mm 68 degree you are at 3.2mm exit pupil, vs 4.3mm in a 32mm plossl. This is one of those cases where, although the 32mm doesn’t gain you much in true field of view, it does help with filtered views due to the larger exit pupil. Of course something like a 2” 42mm Vixen would give you 5.6mm which is even better but try the plossl first.

Larger exit pupils can count against you under light polluted skies, giving poorer contrast, but with narrowband filters and preferable darker skies, a larger exit pupil really helps pull out the fainter nebulae.

Stu the nearest I have is a 27mm Panoptic and an Aero 40mm, does it matter if the filter is connected to the diagonal or eyepiece ?

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2 minutes ago, Pig said:

Stu the nearest I have is a 27mm Panoptic and an Aero 40mm, does it matter if the filter is connected to the diagonal or eyepiece ?

Well if you can get hold of a decent 2” OIII I would give the 40mm a go.

I have Lumicons, but I think Astronomik are best currently available on the market. Could try picking up a used one.

Are you at SGLSP this year? Could always borrow one of mine to try?

It doesn’t matter whether it goes on the diagonal or the eyepiece barrel, it will work in both.

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4 minutes ago, Stu said:

Are you at SGLSP this year? Could always borrow one of mine to try?

It doesn’t matter whether it goes on the diagonal or the eyepiece barrel, it will work in both.

Thanks, I will be at SGLSP so I will take you up on the offer 😀

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2 minutes ago, Pig said:

Thanks, I will be at SGLSP so I will take you up on the offer 😀

:) :) 👍 👍

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7 minutes ago, Stu said:

Let us know how you get on Jock. Which scope do you have and which objects did you try? It may have been that the relatively small fov increase just allowed you to see the edges of the object and gave you the contrast to see it?

Stu I was using my Tak 100dl with the O III filter and 24mm Panoptic tried them on the Veil & m27.

Didnt realise how large a target  the Veil is, and M27 was like a fluffy cotton wool bud. 

You may well be right as far as the increase in fov and contrast goes, will do a direct comparison between the 25mm plossl & 24mm panoptic next clear night.

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I actually went down the path of Astonomik's largely on the back of what John had to say about his Olll at the time and got an Olll, also Lumicon always seemed hard for me to get out here which put me off. I do have the one Lumicon filter which they called their Deep Sky Filter I believe, though I understand it was aimed at LP for the most part. I have found it helps on galaxies with my 12 and 18 inch, just a little but any help is nice

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20 hours ago, Stu said:

Well if you can get hold of a decent 2” OIII I would give the 40mm a go.

I have Lumicons, but I think Astronomik are best currently available on the market. Could try picking up a used one.

Are you at SGLSP this year? Could always borrow one of mine to try?

It doesn’t matter whether it goes on the diagonal or the eyepiece barrel, it will work in both.

Hey Stu... I just purchased the 2” Astronomik 😀 more retail therapy whilst its ⛅️ 

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16 minutes ago, Pig said:

Hey Stu... I just purchased the 2” Astronomik 😀 more retail therapy whilst its ⛅️ 

Crikey, you don’t mess around :) 👍

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17 hours ago, Sagitta said:

Those look interesting. Found them here; https://www.astroshop.eu/telescope-accessories/filters/nebulae-filters/15_15_30/m,Tele-Vue-Optics.

I'm using an old Lumicon OIII now, and an Astronomik UHC, might go for that newer OIII now.

 

What the heck?  $350 in Europe where they're made and only $200 in the US (w/free shipping) where they're imported into?  Even if I subtract out VAT, it's still $294 plus shipping!  Somebody is taking a nice cut somewhere along the line to boost the price 50%.

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38 minutes ago, Louis D said:

What the heck?  $350 in Europe where they're made and only $200 in the US (w/free shipping) where they're imported into?  Even if I subtract out VAT, it's still $294 plus shipping!  Somebody is taking a nice cut somewhere along the line to boost the price 50%.

I think some of the cost will be due to TV doing additional tests to the Astronomik ones. Made in Germany and tested by Astronomik, shipped to the US and retested by TeleVue and then shipped back to Europe again.

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