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APM XWA Advice

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#1 GiantPlaidMonk

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Posted 26 September 2021 - 08:57 PM

Hello all,

 

Understanding of course that everything in the world is out of stock, but I'm intrigued by the 100* range. I have a pretty decent set of eyepieces, but always on the lookout for upgrades :) 

 

If / when APM XWAs make it back to market, which of the 20mm, 13mm or 7mm would you get for a 10" f5 dob? Haven't invested in a coma corrector yet, but these untrained eyes have been pretty pleased with the views so far.

 

And kind of related - do the 20 and 13 barlow well?

 

Thanks and clear skies!



#2 SeattleScott

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Posted 26 September 2021 - 10:57 PM

Probably want coma corrector first. Otherwise there really isn’t a huge point in hyperwides.

Yes, you can ignore the comatic outer 20%. But if you aren’t going to be able to use the outer 20%, why not save money and weight and stick with 82 AFOV? At F5 without coma corrector, 82 AFOV is pushing it for me.

Scott
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#3 YeloSub

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Posted 27 September 2021 - 12:27 PM

Everyone has a different sensitivity to coma, whether based on eyesight, experience, or just preferences. Try without and you may be fine. Maybe borrow a cc and see if it makes a difference for you.

I have all the APM XWA except the 3.6mm. Love them. I mainly care about using the cc with the 20mm.

Use astronomy.tools to check out how eypeices work with your scope. Really useful tool.

Attached is a screenshot of the XWA and your 10"

Hope that helps.

Jakee979aeac435fa8fe9abcd3ea44492815.jpg
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#4 Starman1

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Posted 27 September 2021 - 02:09 PM

Hello all,

 

Understanding of course that everything in the world is out of stock, but I'm intrigued by the 100* range. I have a pretty decent set of eyepieces, but always on the lookout for upgrades smile.gif

 

If / when APM XWAs make it back to market, which of the 20mm, 13mm or 7mm would you get for a 10" f5 dob? Haven't invested in a coma corrector yet, but these untrained eyes have been pretty pleased with the views so far.

 

And kind of related - do the 20 and 13 barlow well?

 

Thanks and clear skies!

APM 13mm will be back in stock shortly, so only the 20mm is scarce and delayed from the factory.

The 20mm Stellarvue Optimus is the same eyepiece if you didn't want to wait for the 20mm.

 

But, let's look at the 10" dob. 1270mm focal length at f/5.

Let's look at a reasonable range of eyepieces yielding 50-250x (all usable) in 50x increments.

That is 25mm, 12-13mm, 8-9mm, 6-7mm, 5mm

In the APM XWA series, that would be 13mm, 9mm, 7mm, 4.7/4.8mm.  You could use the 20mm, but I'd look for something in the 24-26mm range for a low power instead.


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#5 cst4

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Posted 27 September 2021 - 02:43 PM

Looking at the collection in your signature, I recommend going for the 7mm XWA to replace that XCel LX.  I really like that particular XCel piece, but I love the long drift time an XWA can give at higher mags.  It's of course 3 or 4 times the size though... 


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#6 SeattleScott

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Posted 27 September 2021 - 03:45 PM

You asked if they barlow well. The 20mm is 2” so it would require a 2” barlow, and you would want to make sure to get one with enough clear aperture, say 35mm or so. Consider that these are big, heavy eyepieces. Consider that a 2” barlow is rather big and heavy. Consider that you can’t really make good use of the entire FOV without a coma corrector, which is also somewhat big and heavy. So now you have this big, heavy stack soaring out the side of your scope, requiring attention to balance. For most people, the decision about barlowing hyperwides comes down to logistics rather than performance. The performance might be fine, but they don’t want to deal with that tall, heavy stack.

I would also question getting the 20mm, especially if not using a coma Corrector or Goto/Push To. If you are using a low power finder eyepiece to locate targets, you want to be able to utilize nearly the entire FOV. Once you locate a target, you can switch to medium power, and the edge doesn’t have to be great. Just the center 70% or so. But for locating stuff you want to be able to use the whole view.

Scott

Edited by SeattleScott, 27 September 2021 - 03:54 PM.

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#7 GiantPlaidMonk

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Posted 27 September 2021 - 08:54 PM

APM 13mm will be back in stock shortly, so only the 20mm is scarce and delayed from the factory.

The 20mm Stellarvue Optimus is the same eyepiece if you didn't want to wait for the 20mm.

 

But, let's look at the 10" dob. 1270mm focal length at f/5.

Let's look at a reasonable range of eyepieces yielding 50-250x (all usable) in 50x increments.

That is 25mm, 12-13mm, 8-9mm, 6-7mm, 5mm

In the APM XWA series, that would be 13mm, 9mm, 7mm, 4.7/4.8mm.  You could use the 20mm, but I'd look for something in the 24-26mm range for a low power instead.

Very useful input, thanks Don! I do have a 30mm UFF clone for low-power, but was impressed with the more contrasty views I was getting through the 20mm ES68, and was wondering about an upgrade. But as you have said elsewhere in the forum, maybe I should consider investing in eyepieces yielding in and around an exit pupil of 2. Very happy with the 9mm Morpheus (I have an Orion 10" dob, so 1200mm FL, thus an exit pupil of 1.9), so maybe I should zero in on upgrading the 7mm (exit pupil 1.48), giving me a better spread of wide-field for planets in the 5mm-9mm range. 


Edited by GiantPlaidMonk, 27 September 2021 - 08:56 PM.

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#8 GiantPlaidMonk

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Posted 27 September 2021 - 08:55 PM

Looking at the collection in your signature, I recommend going for the 7mm XWA to replace that XCel LX.  I really like that particular XCel piece, but I love the long drift time an XWA can give at higher mags.  It's of course 3 or 4 times the size though... 

Given the feedback so far, I'm thinking you're right! Thx for the reply.



#9 GiantPlaidMonk

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Posted 27 September 2021 - 08:57 PM

You asked if they barlow well. The 20mm is 2” so it would require a 2” barlow, and you would want to make sure to get one with enough clear aperture, say 35mm or so. Consider that these are big, heavy eyepieces. Consider that a 2” barlow is rather big and heavy. Consider that you can’t really make good use of the entire FOV without a coma corrector, which is also somewhat big and heavy. So now you have this big, heavy stack soaring out the side of your scope, requiring attention to balance. For most people, the decision about barlowing hyperwides comes down to logistics rather than performance. The performance might be fine, but they don’t want to deal with that tall, heavy stack.

I would also question getting the 20mm, especially if not using a coma Corrector or Goto/Push To. If you are using a low power finder eyepiece to locate targets, you want to be able to utilize nearly the entire FOV. Once you locate a target, you can switch to medium power, and the edge doesn’t have to be great. Just the center 70% or so. But for locating stuff you want to be able to use the whole view.

Scott

Good points here - never having seen a 100* EP up close, I'm probably underestimating its bulk. Thanks for the advice!



#10 YeloSub

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Posted 27 September 2021 - 10:09 PM

The 100° offering are a large bunch, but the APM versions are particularly light for their class, which is one reason they have become so popular.
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#11 SeattleScott

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Posted 27 September 2021 - 10:25 PM

This is true. They are light as hyperwides go. Still big, still heavy, but not as bad as ES or some others.

The OP might want to check out the Holy Mackerel thread.

Scott
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#12 Miranda2525

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Posted 28 September 2021 - 10:34 AM

Everyone has a different sensitivity to coma, whether based on eyesight, experience, or just preferences. Try without and you may be fine. Maybe borrow a cc and see if it makes a difference for you.

I have all the APM XWA except the 3.6mm. Love them. I mainly care about using the cc with the 20mm.

Use astronomy.tools to check out how eypeices work with your scope. Really useful tool.

Attached is a screenshot of the XWA and your 10"

Hope that helps.

Jakee979aeac435fa8fe9abcd3ea44492815.jpg

Can't see what's going on with this attachment at all. It's far too small, lol.


Edited by Miranda2525, 28 September 2021 - 05:12 PM.


#13 Miranda2525

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Posted 28 September 2021 - 10:39 AM

The 100° offering are a large bunch, but the APM versions are particularly light for their class, which is one reason they have become so popular.

Yes, but add a coma corrector, and the stack adds up. 

 

20mm APM 100 is 1.5 Lbs. Add the coma corrector, (which is needed for the very best views), and you're looking at around 2.25 Lbs !!! Even without the CC, 1.5 lbs isn't attractive to some.


Edited by Miranda2525, 28 September 2021 - 05:09 PM.

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#14 GiantPlaidMonk

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Posted 28 September 2021 - 12:15 PM

Everyone has a different sensitivity to coma, whether based on eyesight, experience, or just preferences. Try without and you may be fine. Maybe borrow a cc and see if it makes a difference for you.

I have all the APM XWA except the 3.6mm. Love them. I mainly care about using the cc with the 20mm.

Use astronomy.tools to check out how eypeices work with your scope. Really useful tool.

Attached is a screenshot of the XWA and your 10"

Hope that helps.

Jakee979aeac435fa8fe9abcd3ea44492815.jpg

 

 

The 100° offering are a large bunch, but the APM versions are particularly light for their class, which is one reason they have become so popular.

 

Thanks for the notes! I understand the APM XWA range differs a bit in stated eye relief. Is it that noticeable in practice? I take off my glasses to observe, but am a bit spoiled from my current set which doesn't go below 15mm ER (the ES 68). Have you ever had trouble with eye placement on the 13mm or 7mm? Do you use them in a comparable large dob as well?



#15 Voyager 3

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Posted 28 September 2021 - 12:18 PM

Can't see what's going on with this attachment at all. It's fart too small, lol.

I know it's a typo but this made my day . L M A O 😂


Edited by Voyager 3, 28 September 2021 - 12:19 PM.

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#16 YeloSub

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Posted 28 September 2021 - 12:19 PM

I don't wear glasses (contacts) and have no issues with eye relief in any of them. Yes tighter than some of your ES68s which I have used as well. Others like the ES68s or Morpheus are definitely more comfortable to use eye relief wise. But I have no issue with the XWAs. Compared to the ES82s I have used, especially at the shorter focal lenghts are comparable to the XWA. Specifically I like the XWA better for the 7 and 9mm range.
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#17 Miranda2525

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Posted 28 September 2021 - 05:10 PM

I know it's a typo but this made my day . L M A O

OMG, I just noticed this, HAHAHAHA !!!! lol.gif

 

Miranda2525, on 28 Sept 2021 - 11:34 AM, said:

Can't see what's going on with this attachment at all. It's fart too small, lol.

 


Edited by Miranda2525, 28 September 2021 - 05:12 PM.

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#18 havasman

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Posted 28 September 2021 - 05:40 PM

And kind of related - do the 20 and 13 barlow well?

I don't like the idea of Barlowing 2" eyepieces. And the APM HDC's are, for me, 2" eyepieces. It just makes too tall a stack and is too fiddly for me. The APM HDC's are really good. I've owned or own 20, 13, 9 & 7mm's along with ES100 20, 14 & 9 and Ethos 21, 13, 10, 6, 4.7 & 3.7 Ethos. The APM's and Ethos are the best. ES100's are heavy and less crisp for me in my scopes; their exit was long ago. The APM's are lightest and handle well. I sold the 13E and 6E and replaced them with 13 & 7mm APM's and sold the APM HDC 20 and replaced it with the 21E. I recommend the APM's a great bargains in today's market and very high performance units.

 

All those ep's are/were used very successfully in f4.49 to f4.7 Dobs (all 100% with Paracorr 2) and in f5.4 refractor.


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#19 vrodriguez2324

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Posted 28 September 2021 - 07:56 PM

I have an 8 inch F5 Newtonian Reflector, the complete series of the of the XWA/Stellarvue 100 degree eyepieces, and a Tele Vue Paracorr type 1.  I have tried them a few times sans Paracorr, and every time I am happy I have one to put in the optical chain. The coma corrector really cleans up the view nicely especially at the longer focal lengths. 

 

Without a coma corrector edge performance increases as the focal length decreases. The 20mm without a coma corrector has the worst edge performance of the series.

 

Something to consider is that the Paracorr also decreases the exit pupil size since it increase the F ratio from 5 to 5.75.

 

The 13mm with a Paracorr gets you closer to a 2mm exit pupil and the 7mm with a Paracorr gets you closer to a 1mm exit pupil. 

 

How much coma detracts from the view varies from one observer to the next. I like pinpoint stars going to as close to the edge as possible. I didn't know I liked it until I tried a Paracorr. 

 

Another thing to consider is what happens next. I picked up a 9mm 100 degree eyepiece and really liked the presentation. So much in fact that now I have two sets of eyepieces. 

 

1. A Super/Ultra Wide set (70-82 degrees) including XW's, Morpheus, and Naglers

2. An Ultra/Hyper Wide Set (82-110 degrees) including Meade UWA, Stellarvue, XWA, and Ethos


Edited by vrodriguez2324, 28 September 2021 - 07:56 PM.

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#20 Victor Martinez

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Posted 30 September 2021 - 02:59 AM

I had the Ethos 21, 13, 10 and 8, which together with a Paracorr II on a 16 "f5 with Ostahowski optics offered some beastly images. For irrelevant reasons I got rid of all the material. After a while I bought a second-hand pack of ES 20, 14 and 9 eyepieces that I was testing with a SkyWatcher 120 ED refractor, but there was something about them that did not quite convince me. Finally seeing the good reviews of the APM XWA, I got hold of the 20, 13 and 9. From my point of view very close to the Ethos and indisputably better than the ES.


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#21 vkhastro1

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Posted 30 September 2021 - 04:17 AM

Just completed my full set of the APM HDC 100 degree eyepieces with the purchase of the newest 7mm release.

Definitely recommended !


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#22 spaceoddity

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Posted 01 October 2021 - 07:47 PM

IMO 100 degree eyepieces can be enjoyed with or without a coma corrector, especially at F/5. If it doesn't bother you with your current eyepieces, don't even worry about it. When it does start to bother you, that's when you need one. It may be never. I don't always use one even with my 16" F/4.5 as it's one less thing I have to fiddle with, although I have a GSO CC and paracorr type 1(w/tunable top). Nobody even makes 1.25" CC for my 5" F/5 tabletop dob.

 

Anyhow, I love the APM XWA's and looking at your current eyepieces I'd say the 7 mm would be the most useful to replace the x-cel. Those higher powers is where you will appreciate the longer drift time the most and it looks like you are pretty set at the other magnifications. I've only used the 7mm once and the eye relief seemed a little tighter than the 9 and 13 to me but I don't wear glasses so not a big deal. 

 

The 9 and 13 XWA's are my favorites with my 16" dob. I can do a whole session with just those 2 eyepieces actually, love them.


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#23 GiantPlaidMonk

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Posted 03 October 2021 - 11:06 PM

Thanks for the feedback and suggestions everyone! I'm thinking when I take the plunge into 100* land, it'll be with the 7mm. Cheers!



#24 kongqk

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Posted Yesterday, 10:26 PM

Thanks for the feedback and suggestions everyone! I'm thinking when I take the plunge into 100* land, it'll be with the 7mm. Cheers!

You will love it, 7 mm is a really nice one, I also got mine recently ^)^



#25 kongqk

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Posted Yesterday, 10:28 PM

Just completed my full set of the APM HDC 100 degree eyepieces with the purchase of the newest 7mm release.

Definitely recommended !

Same here, almost complete my set, and still waiting for some of them which is in back-order. But the ones I have so far works really well. 




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