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Eyepiece help please


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If you will be getting both , then get the UHC first . It is more universal and will give a huge boost for the more famous nebulae like M8 , M17 , M42 , M16 etc . 

 

The  get the OIII for use with some supernova remnants , wolf -rayet excitation nebulae , large planetary nebulae etc . 

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3 hours ago, Voyager 3 said:

If you will be getting both , then get the UHC first . It is more universal and will give a huge boost for the more famous nebulae like M8 , M17 , M42 , M16 etc . 

 

The  get the OIII for use with some supernova remnants , wolf -rayet excitation nebulae , large planetary nebulae etc . 

The O-III is worth having for the Veil Nebula complex alone. There really is so much to see there :icon_biggrin:

A UHC will show it but an O-III is has much more impact.

Edited by John
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10 minutes ago, John said:

The O-III is worth having for the Veil Nebula complex alone. There really is so much to see there :icon_biggrin:

A UHC will show it but an O-III is has much more impact.

100% agree.

Get a good OIII first IMHO.

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1 hour ago, jetstream said:

100% agree.

Get a good OIII first IMHO.

I wouldn't recommend O-III filters as a "first" nebula filter purchase, because they don't work as well on the large hydrogen gas clouds like M42/43, M8, M17, M20, M16, etc. as a narrowband filter.

They do, however, work a bit better on planetary nebulae, some supernova remnants (though I think a narrowband works better on M1), and Wolf-Rayet excitation nebulae.

Ultimately, I think astronomers should have a set of at least 2 nebula filters--one good narrowband, and one good O-III.

But, since the narrowband does pass the O-III lines and is usable on more different nebulae, I'd start with that one first.

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I understand your points Don and an agree -with a caveat- and that is sky conditions. Under truly dark skies the UHC is reached for first many times- actually I just flick the filterslide back and forth to compare.

Under less than dark skies the additional "contrast" provided by the OIII is a big asset.

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52 minutes ago, Jiggy 67 said:

……..It’s neck and neck!!  Nothing to split between the UHC and 0III !!…….🤣😀

Then getting both the filter at the same time is the best solution to please all of us . :evil: 

 

Just kidding , buy either of them first , keeping in mind that you will be buying the other eventually . If you really get into this hobby and have a good dark site , a H-beta filter will be a good tertiary filter . 

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3 hours ago, John said:

The O-III is worth having for the Veil Nebula complex alone. There really is so much to see there :icon_biggrin:

A UHC will show it but an O-III is has much more impact.

A good rich field refractor , a dark site , an OIII filter can keep anyone busy for a lifetime . The Veil nebula bubble helps too . 😀

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I've been down this route as well:

Current EP's

APM 5, 13 and 20 mm XWA

-> 20 mm XWA on back order since February, good to use if you have less contrast available due to < 21 SQM at your viewing site. 

APM 30 mm UFF and 2x 24 mm UFF

Astronomik OIII filter

Now BV's currently sourcing Max Bright II, hard to get like all astro equipment.

For BV use planning to use 24 mm UFF 

Will add for BV use

17.5 mm Morpheus

12.5 mm Takahashi Abbe.

I'd hold off not he 17 mm APM XWA as maybe to much overlap with the 17.5 mm Morpheus for BV use.  

Edited by Deadlake
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1 hour ago, Deadlake said:

For BV use planning to use 24 mm UFF 

I picked up my used copy from someone who couldn't get on with a pair of them in his BV.  I don't know if it was due to an IPD issue, a nose space issue between them, or something else entirely like weight or ability to merge images.  Just temper your expectations for the 24mm UFF pair in a BV.

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On 01/09/2021 at 22:51, Louis D said:

Not so much aperture as large exit pupil.  Yes, that will mean lower magnification with smaller aperture scopes, but that can be a good thing for large objects like the Veil nebula.

If I had started with my Lumicon UHC, I probably would have written off all nebula filters as "Meh".  Some improvement, but not a dramatic improvement in the view.  The OIII is a "Wow" filter with what it can bring out.  Invisible nebula like the Veil stand out as etched on the sky.  Remove it, and the Veil disappears.

Is the OIII filter right for all emission nebula?  Certainly not.  However, more often than not, it offers a very noticeable improvement in the view.

if you go dark you can still see the veil without a filter. but better with it👍

Edited by faulksy
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On 01/09/2021 at 18:27, Voyager 3 said:

You will be using a Paracorr II / paracorr for the best correction to use with 100° stuff . It adds 1.15× to the FL/ Focal ratio . 

 

So I take the FL as 1878 . 

Here is your spread with 30mm ( UFF )-13mm-9mm-4.75mm( really a 4.75mm approximately and not a 5mm ) . The 30mm can be substituted by the 20mm XWA  , if your site is light polluted . 

62× - 144× - 208× - 395×  . 

As you can see this is a good set until you reach the 9mm . It's a really big jump from 9mm to 4.75mm . 

A 6mm Ethos fits right in at 313× , but the 7mm APM XWA will also be a good step up at 268× . 

Now it looks like 

62× - 144× - 208× - 268× - 395× . 

Basically you may still need to fill the gap between 7mm and 4.7mm but it is down the list . A coma corrector like the paracorr II must be your first purchase . This assumes you already have good collimation tools . 

 

Wow this eyepiece thing is complex!

so I've decided to ditch the 30mm UFF - too large an exit pupil in light polluted skies - so want something in the 20-24 region I think as my lowest - to start with.  So there's the 24mm APM UFF - I assume this would be great without a parracor, or the 24mm Panopticon,or the 22T4 Nagler or the 20mm APM XWA - which I would assume both require a parracor at f4.6?  Although the Nagler is stated as for f5 and above.  Any views on which one to go for?  I really want the wider FOVs in a manual dob if possible.

I was then thinking of a 6mm, 9mm and 13mm to complete an initial set (4.7mm at 340x too much magnification?)  Which of those am I likely to use most?  For varied use - planets, nebulae and DSO?  As I think I will get 1 Ethos and 2 APM 100 XWA.

 

If I need a parracor I will probably only be able to go for 2 eyepieces initially with the rest at xmas - so the 20mm and which other would give me best bang for buck?  Or if I go for three and no parracor, would you go 6,9,20 or 9,13,20 for example?

Thanks again for all your great advice!

Nic

Edited by Astro_Nic
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The 20mm APM XWA would probably work well for you except that it isn't in stock anywhere.

The 22mm NT4 won't correct for coma.  Al is simply stating it is well corrected in an f/5 scope for things such as astigmatism and chromatic aberrations near the edge.  The APM XWA won't be too much different.

The 24mm APM UFF and 24mm Panoptic wouldn't come close to your goal of (nearly) maximizing true field of view.

The 13mm would probably get used the most since it provides a nice (high) mid-power.

Instead of a Paracorr II, you could start with a GSO coma corrector (Revelation, Omegon, TPO, Astro Tech, Apertura, etc.) and a 25mm M48 spacer ring between the optical element and the eyepiece holder if your budget is tight.  It will correct 90%+ of the coma in that configuration for eyepieces that focus within 5mm of their shoulder.

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  • 2 weeks later...

OK thanks for all your help.  I think I am going to go with the following to start with:

9mm APM XWA

13mm APM XWA

22mm Nagler T4

Paracorr II

Astronomix OIII

Polarising moon filter - suggestions?

Red torch

 

How does that sound?  Now need to read up on collimation....am clueless! lol

Thanks

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I have use and one of these...

1_25filter.jpg.7ec846496e5cb1023cb990df9a7099a4.jpg    5addf27ccac70_variablemoonfilter.jpg.e490ce031fc7badb2a139b6d8384c995.jpg

via a well known auction site.

note: I would not recommend you use the eyepiece holder with heavy
e/p's. Just unscrew it and attach to your chosen e/p. There are four parts
in total, including one locking screw (not shown).

 

And I have and use one of these...

59981841-27DF-483D-A217-AB1143AFE32F.jpeg.f1b039e0fb956116c9d774279986ace8.jpeg.2cc4203ca7f4cf252c15a88d6973ebdc.jpeg

for my 2" eyepiece.

Edited by Philip R
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Thanks, I'll check out the filters.

 

My other main concern was whether to go with the 20mm APM XWA 100 degree or the 22mm Nagler T4 - Most people seem to rave about their 22 NT4 so went with that, but I know the APM has a good following too.

 

The other issue is whether I need a higher FL eyepiece than 20/22 such as a 30mm APM UFF - some have suggested that the 22 NT4 won't have a large enough FOV at the 83x magnification.  I am concerned with a larger exit pupil giving a brighter background in my Bortle 5ish sky so thought the 22 would be a good compromise. A 30mm would give 59x mag.

 

Thanks again.

 

Nic

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I have both the 30mm APM (61x) and the 22mm Nagler (83x).  The 22 gets 90% of the eyepiece time.

Field sizes are 36.4mm and 31.1mm respectively.  In my scope, 1.14° and 0.98° respectively.

That makes the 30mm 17% wider in true field.  I use it when the wider field and lower magnification are needed, which isn't often.

Normally, I prefer the darker background of the 22mm, and that is in a site with a 21.4+ sky (~mag.6.9NELM).

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I find a similar thing with my Nagler 31mm and Ethos 21mm - the Ethos 21 gets a lot more use with my 12 inch F/5.3 dobsonian. If my skies were ultra-dark then the Nagler 31 would probably get more use though.

 

 

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  • 4 weeks later...
On 17/09/2021 at 09:26, Astro_Nic said:

Thanks, I'll check out the filters.

 

My other main concern was whether to go with the 20mm APM XWA 100 degree or the 22mm Nagler T4 - Most people seem to rave about their 22 NT4 so went with that, but I know the APM has a good following too.

 

The other issue is whether I need a higher FL eyepiece than 20/22 such as a 30mm APM UFF - some have suggested that the 22 NT4 won't have a large enough FOV at the 83x magnification.  I am concerned with a larger exit pupil giving a brighter background in my Bortle 5ish sky so thought the 22 would be a good compromise. A 30mm would give 59x mag.

 

Thanks again.

 

Nic

I just went through the same thing, but not an entire eyepiece lineup change. I owned the 22mm Nagler T4 and now I own a 20mm APM XWA 100°. I also own a coma corrector. Field curvature was still seen in the telescope and the coma corrector, so I sold the 22mm T4 and I am more than happy with the 20mm APM XWA over the 22mm T4 Nagler. When removing the 20mm APM XWA, the only thing I see is pure coma. There is no FC at all in that EP.

I would take the 20mm APM XWA over the 22mm T4 Nagler without hesitating.

The eye relief on the 20mm XWA is good enough if you want to use glasses. I tried that and it works. My glasses rest against the folded rubber eye guard. It's super immersive and perfect in the coma corrector.

Edited by TheLookingGlass
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4 hours ago, TheLookingGlass said:

The eye relief on the 20mm XWA is good enough if you want to use glasses. I tried that and it works. My glasses rest against the folded rubber eye guard. It's super immersive and perfect in the coma corrector.

Since the eye lens is about the same diameter for both (~30mm), I wouldn't doubt you would be able to see at least as much of the field in the XWA as in the NT4 (~82°) while wearing eyeglasses.  However, can you actually see the entire 100° of the XWA with eyeglasses?  I can just take in the 92° field of my ES92s by resting my glasses against the folded eye guard of each, and they each have a 43mm diameter eye lens!  I tried an Ethos at a star party while wearing eyeglasses and could only see the inner 70° or so with ease, and it also had a ~30mm diameter eye lens.

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16 hours ago, Louis D said:

Since the eye lens is about the same diameter for both (~30mm), I wouldn't doubt you would be able to see at least as much of the field in the XWA as in the NT4 (~82°) while wearing eyeglasses.  However, can you actually see the entire 100° of the XWA with eyeglasses?  I can just take in the 92° field of my ES92s by resting my glasses against the folded eye guard of each, and they each have a 43mm diameter eye lens!  I tried an Ethos at a star party while wearing eyeglasses and could only see the inner 70° or so with ease, and it also had a ~30mm diameter eye lens.

I just tried a 20mm, and the eye relief was too tight to see the entire field with glasses on.

The 22mm Nagler is no problem in that regard.

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5 hours ago, vagk said:

What about Explore Scientific 20mm 100° ?

Has it so much difference from Ethos and APM ?

21mm Ethos - $853.00

20mm ES-100 - $799.99

20mm APM XWA- $329

There's no reason to not spend the extra $53 and buy the Ethos over the ES-100.  However, the APM is less than half the cost of either of the other two.

The APM is lighter than either of the other two (678g vs 968g for the ES-100 and 1021g for the Ethos).  Most reviews on CN comparing the three put the Ethos well out front in correction and contrast in fast scopes with the APM not far behind, suffering only in the outer 10% to 15% of the field and having some slight stray light control issues.  The ES rates similarly to slightly behind the APM.  The 20mm APM is generally regarded as the weakest of the XWA line of eyepieces, and yet gives up nothing to the ES.  There is literally nothing to recommend the ES over the APM unless it were to be availability for immediate purchase.

Edited by Louis D
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