40 mm wide field eyepiece

[Deadlake]

1 hour ago, John said:

The higher magnification will show DSO's better if you have some LP to contend with. Thats why I don't use my Nagler 31 very often compared with my Ethos 21.

The scope will handle a lot higher than 156x of course !

 

The APM 30 mm exit pupil is 5 mm whereas the 20 mm is 3.3 mm...

 Is your Ethos 21 you most used EP at this range? 

Edited February 15, 2021 by Deadlake

[jetstream]

@Deadlake one vg one for filter use and one vg one for general galaxy work. For the latter the 17.3mm Delos is superb, knocking the 17E off the stump for this work.

In your scope a 30mm widefield gets the nod for filter use and something like the mentioned Delos for widefield galaxy use. Of course this is up to personal taste.

[Deadlake]

7 minutes ago, jetstream said:

@Deadlake one vg one for filter use and one vg one for general galaxy work. For the latter the 17.3mm Delos is superb, knocking the 17E off the stump for this work.

In your scope a 30mm widefield gets the nod for filter use and something like the mentioned Delos for widefield galaxy use. Of course this is up to personal taste.

30 mm and 20 mm have similar fields of view from the simulation, however the 20 mm will have higher contrast.

Will the a filter ( UHC or OIII) work better in the 30 mm for some reason???

 

[jetstream]

11 minutes ago, Deadlake said:

Will the a filter ( UHC or OIII) work better in the 30 mm for some reason???

It might be best for you to try some different ones out before buying, to see what works for you.

[Deadlake]

17 minutes ago, jetstream said:

It might be best for you to try some different ones out before buying, to see what works for you.

In the pandemic thats hard...

 

Looking at the Delos 17.3 vs the APM 13mm 100 o same field of view, however I suspect again the APM would win on the contrast...

To complicate matters the APM 30 mm exit pupil is 5 mm whereas the 20 mm is 3.3 mm... 

What the best trade off exit pupil or contrast?

 

Edited February 15, 2021 by Deadlake

[jetstream]

12 minutes ago, Deadlake said:

20 mm is 3.3 mm... 

This is a bit low for OIII use IMHO. The 17.3 mm Delos rapidly became a favourite eyepiece, very bright huge contrast and then there is the Docter UWA...

All these eyepieces need good dark skies for differences to become apparent IMHO.

[Deadlake]

2 minutes ago, jetstream said:

This is a bit low for OIII use IMHO. The 17.3 mm Delos rapidly became a favourite eyepiece, very bright huge contrast and then there is the Docter UWA...

All these eyepieces need good dark skies for differences to become apparent IMHO.

Delos 17.3 mm exit pupil 2.88 whereas APM 13mm is 2.17 mm.  

[jetstream]

19 minutes ago, Deadlake said:

What the best trade off exit pupil or contrast?

Unfiltered this parameter is harder to know, it depends on the skies and observer. The 20mm Lunt is a super eyepiece that shows a tiny bit of astig at the edge with the PCII. This does not bother me one bit.

One known: I would for sure, have one widefield just over 4mm exit pupil for the OIII, nesr 5 if your skies are dark.

[Deadlake]

3 minutes ago, jetstream said:

Unfiltered this parameter is harder to know, it depends on the skies and observer. The 20mm Lunt is a super eyepiece that shows a tiny bit of astig at the edge with the PCII. This does not bother me one bit.

One known: I would for sure, have one widefield just over 4mm exit pupil for the OIII, nesr 5 if your skies are dark.

20 mm Lunt is the same as 20 mm APM, both 100 o?

[jetstream]

1 minute ago, Deadlake said:

Delos 17.3 mm exit pupil 2.88 whereas APM 13mm is 2.17 mm.  

The difference in transmission becomes apparent even though I don't have the 13mm APM. Depends what you want- I love the 14mm Nikon HW eventhough its not the highest trans eyepiece out there- its vg though. All this is going to boil down to how you like the look through the eyepiece IMHO.

Last night the unfiltered view of the Rosette was amazing using the 17mm HW, had I used the 17.3mm Delos the look would be constrained.

One thing for sure- you need an EP for the OIII...

[jetstream]

Just now, Deadlake said:

20 mm Lunt is the same as 20 mm APM, both 100 o?

Yes, same eyepiece.

[Deadlake]

8 minutes ago, jetstream said:

The difference in transmission becomes apparent even though I don't have the 13mm APM. Depends what you want- I love the 14mm Nikon HW eventhough its not the highest trans eyepiece out there- its vg though. All this is going to boil down to how you like the look through the eyepiece IMHO.

Last night the unfiltered view of the Rosette was amazing using the 17mm HW, had I used the 17.3mm Delos the look would be constrained.

One thing for sure- you need an EP for the OIII...

And to get one before prices go up 😃. I thought the 20 mm was a go before looking at exit pupils. Looks like to could justify both, contrasty view in 20 mm where's as for filtered view the 30 mm due to the large exit pupil. Still half the price of an Ethos 21 mm for both APM's and the reviews on CN is good for both from Ethos and Nagler owners. Main plus is views are close but the weight is less especially for Dob owners who don't like counterweights for their EP's... 😀 

Edited February 15, 2021 by Deadlake

[jetstream]

Just now, Deadlake said:

And to get one before prices go up 😃. I thought the 20 mm was a go before looking at exit pupils. Looks like to could justify both, contrasty view in 20 mm where's as for filtered view the 30 mm due to the large exit pupil. Still half the price of an Ethos 21 mm for both APM's and the reviews on CN is good for both. 

I have spent thousand of dollars maximizing my views through trial and error. Forget the 25mmES 100 if you were looking as well as the monster 6 pound 30mm ES 100...

The 30mm UFF is very highly regarded but at f7.5 I need a lower mag EP for the OIII. IMHO buy eyepieces that are known to sell well in the used market then you can play a bit- easier money wise.

If you had the 30mm UFF, 20mm APM and the 13mm APM you would not be lacking by any ones standards IMHO. From there you can fine tune.

[Deadlake]

Just now, jetstream said:

I have spent thousand of dollars maximizing my views through trial and error. Forget the 25mmES 100 if you were looking as well as the monster 6 pound 30mm ES 100...

The 30mm UFF is very highly regarded but at f7.5 I need a lower mag EP for the OIII. IMHO buy eyepieces that are known to sell well in the used market then you can play a bit- easier money wise.

If you had the 30mm UFF, 20mm APM and the 13mm APM you would not be lacking by any ones standards IMHO. From there you can fine tune.

My thoughts are go from the good value products and then replace those you use the most. I read threads on CN where people have gone fully Televue only to find they use just a a few EP's all the time. After this I will retire my Vixen SLV's. If I order now maybe some time in March the order will turn up.

[jetstream]

9 minutes ago, Deadlake said:

My thoughts are go from the good value products and then replace those you use the most. I read threads on CN where people have gone fully Televue only to find they use just a a few EP's all the time. After this I will retire my Vixen SLV's. If I order now maybe some time in March the order will turn up.

Youre not going to see much difference between the 21E and the 20 APM IMHO, edge astig being one difference, and yeah I have them both. If I drop the 20 APM I'll cry, if I drop the 21E I'll jump up and down ,cry and throw a fit over the money I just lost 😀

[Deadlake]

1 minute ago, jetstream said:

Youre not going to see much difference between the 21E and the 20 APM IMHO, edge astig being one difference, and yeah I have them both. If I drop the 20 APM I'll cry, if I drop the 21E I'll jump up and down ,cry and throw a fit over the money I just lost 😀

You also need to be quick, I'd imagine the 21E can do some damage on whatever its landing on. 😀 

[scarp15]

Both a 20mm and a 30mm will become equally purposeful for filtered observing. The 30mm in opening up the exit pupil for large emission nebulae characterised by low surface brightness. The 20mm for a more dynamic observation of brighter emission nebulae. 21+mag SQM registered skies will enhance 30mm, larger exit pupil / filtered observations. An example, in my 8" F6; 21mm equates to 3.5mm exit pupil, 31mm; 5.2mm. It takes considerable time to arrive at a eyepiece selection that is applicable for all of your observing criteria. Buying and selling used helps, get the best you can first time if possible, it may then still be with you and valued in years to come.

[Deadlake]

13 minutes ago, scarp15 said:

Both a 20mm and a 30mm will become equally purposeful for filtered observing. The 30mm in opening up the exit pupil for large emission nebulae characterised by low surface brightness. The 20mm for a more dynamic observation of brighter emission nebulae. 21+mag SQM registered skies will enhance 30mm, larger exit pupil / filtered observations. An example, in my 8" F6; 21mm equates to 3.5mm exit pupil, 31mm; 5.2mm. It takes considerable time to arrive at a eyepiece selection that is applicable for all of your observing criteria. Buying and selling used helps, get the best you can first time if possible, it may then still be with you and valued in years to come.

Good to know, backyard is 20.5 SQM, I suspect measurement is directionally.

[John]

Sorry, I've rather lost track of this thread lately

Looks like you are getting so good advice though

Edited February 15, 2021 by John

[Deadlake]

10 minutes ago, John said:

Sorry, I've rather lost track of this thread lately

Looks like you are getting so good advice though

No worries John. Modelling the EP helps a lot, I forget to check the exit pupil...  😀

Edited February 15, 2021 by Deadlake

[Louis D]

8 hours ago, Deadlake said:

Given the cost of TeleVue, which ones would you buy and which ones would you buy another brand as you don't use them enough?

My 22mm Nagler T4 is the only Tele Vue I've kept in my A-team case because there's no good alternative to it for 82+ degree field and long eye relief at the focal length.

[John]

10 hours ago, Deadlake said:

Given the cost of TeleVue, which ones would you buy and which ones would you buy another brand as you don't use them enough?

I'm sorry - I missed this question.

17mm is my most underused focal length. I replaced the Ethos 17mm with an ES 17mm / 92 because of this and I've thought about letting my 17.3mm Delos go as well but I keep finding excuses to hang onto it, usually after I've read a report from someone else saying how much they like the eyepiece

I guess a 17.5mm Morpheus would fill the gap very adequately but, as I tend to move directly from 20-something mm eyepieces to 13mm / 14mm eyepieces the poor 17mm's get overlooked so the Morpheus would get similar treatment I expect.

Other than that, I think my current Tele Vue's are "keepers". Probably .......

There are a few out there that might be a touch better in certain focal lengths but they cost even more than the Ethos's do.

 

 

[Deadlake]

4 minutes ago, John said:

I'm sorry - I missed this question.

17mm is my most underused focal length. I replaced the Ethos 17mm with an ES 17mm / 92 because of this and I've thought about letting my 17.3mm Delos go as well but I keep finding excuses to hang onto it, usually after I've read a report from someone else saying how much they like the eyepiece

I guess a 17.5mm Morpheus would fill the gap very adequately but, as I tend to move directly from 20-something mm eyepieces to 13mm / 14mm eyepieces the poor 17mm's get overlooked so the Morpheus would get similar treatment I expect.

Other than that, I think my current Tele Vue's are "keepers". Probably .......

There are a few out there that might be a touch better in certain focal lengths but they cost even more than the Ethos's do.

 

 

Really, what costs more then a Televue, E21 are now £900.

[jetstream]

11 minutes ago, Deadlake said:

Really, what costs more then a Televue, E21 are now £900.

Thats a lot... I paid just over half that-new... actually less because I bought when the CDN and USD were near par.

The Nikon HW 17/14/EIC is a super eyepiece with the most ridiculous eye cup I've seen. The Ethos eyecup fits perfectly though lol!

My line up: 20mm Lunt, 17/214 HW, Docter UWA, Delos 10mm, Delos 8mm.

Then of course theres the planetary/lunar eyepieces...

oh yeah, the widefield frac eps 42 LVW, 30 ES 83

jeez forgot these other ones...😀... etc etc Ethos,Zeiss, Leica..HR's, orthos..

Normally I take 2 or three out!

Tonight the LVW/HW and Zeiss zoom get the nod for the 120mm frac.

[Deadlake]

12 minutes ago, jetstream said:

Thats a lot... I paid just over half that-new... actually less because I bought when the CDN and USD were near par.

The Nikon HW 17/14/EIC is a super eyepiece with the most ridiculous eye cup I've seen. The Ethos eyecup fits perfectly though lol!

My line up: 20mm Lunt, 17/214 HW, Docter UWA, Delos 10mm, Delos 8mm.

Then of course theres the planetary/lunar eyepieces...

oh yeah, the widefield frac eps 42 LVW, 30 ES 83

jeez forgot these other ones...😀... etc etc Ethos,Zeiss, Leica..HR's, orthos..

Normally I take 2 or three out!

Tonight the LVW/HW and Zeiss zoom get the nod for the 120mm frac.

And a Barlow 😃🥳😁

ps: E21 are £810, just checked, well until next week.

Edited February 15, 2021 by Deadlake