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Old 01-12-2021, 04:07 PM
Ryan101 (Ryan)
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Pentax xw5mm or Morpheus 6.5mm

Hey,
I have a 12 inch dobsonian and am looking to upgrade to a good high power eyepiece.

All I have for now is a 2x barlowed 17mm Hyperion or the 10mm plossl 2x barlowed that came with the scope.
I'm not looking at a televue.
I am however looking at the Pentax xw 5mm or the Baader morpheus 6.5mm.

The Pentax would be nice but is more expensive. The Morpheus would be nice but at 6.5mm is close to my 2x barlowed 17mm Hyperion. The Morpheus barlowed would be 3.25mm but is 460 odd power just too unrealistic.

I do have access to a dark sky from time to time though.
Any help would be greatly appreciated. Either one is a lot of cash for me so I don't want to mess this up.
If anyone has a second hand one of these up for grabs, please let me know.
Cheers.
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Old 01-12-2021, 05:24 PM
astro744
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How often do you use observe at 300x with the 10mm/2x Barlow and what targets do you prefer? The 230x of the 6.5mm would be used more often I would think but 300x is certainly attainable for say planets with a 12” mirror giving 1mm exit pupil so a relatively bright image. Seeing and quality of optics (surface accuracy and collimation) will be the determining factors.

What about something in the 12-13mm range which you could then Barlow to get 6-6.5mm? Or replace the 10mm Plossl with a 10mm Pentax which you could Barlow to get the 5mm you desire.

If your only issue with Tele Vue is cost then consider used. There is a 13mm T6 Nagler in the classifieds at present or at least was last time I checked. This one would be fantastic in your telescope for large globular clusters and nebulae as well as planets both Barlowed and non-Barlowed. (Quality of Barlow will impact on quality of view).

There is also a used 4.7mm/82 Meade for sale in the classifieds. Not sure if you’re considering this one. I don’t like recommending eyepieces I haven’t used and I haven’t used either Pentax 10 XW or the Meade 4.7/82. I have used the Nagler 13/T6 and it would perform very well at f5 with the only aberration seen being primary mirror coma which you could remove with a Paracorr. (The coma would be tony and for most non-objectionable at f5). The would be no astigmatism from the Nagler. I’m sure others can vouch for the other eyepieces if the Tele Vue is still too pricey used.

Last edited by astro744; 01-12-2021 at 05:48 PM. Reason: Added last para.
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Old 01-12-2021, 06:07 PM
Ryan101 (Ryan)
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The televues are too pricey but second hand for a good price would be fine.

The problem is that I don't understand what would best suit an F5 Newtonian in their range.

I looked at the Parracor and yep they're extra pricey, but at my low level of experience I don't think I would notice much difference with or without one.
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Old 01-12-2021, 06:09 PM
Ryan101 (Ryan)
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Oh yeah, at the moment I'm really enjoying hunting down planetary nebula and splitting doubles. Of course Jupiter but who doesn't enjoy Jupiter.
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Old 02-12-2021, 03:23 AM
astro744
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Skip the Paracorr until you can appreciate the difference one makes and even then at f5 you will likely observe just as often without one. It’s very much a personal decision. The biggest improvement is seen with a well corrected eyepiece for the f5 light cone. Tele Vue offers a variety of well corrected eyepieces to suit your needs offering different apparent fields and eye relief.

See https://www.televue.com/engine/TV3b_page.asp?id=154

and check out each link including the individual eyepiece links (from their home page). Plenty to read and learn with no obligation to buy.

Mainly what you are paying for in well corrected eyepieces is the improvement in the outer view towards to edge and the larger apparent field that you get but there are many other factors that contribute to a good eyepiece and a good view. If starting off on your observing journey you’ll be looking at targets in the middle of the field and won’t be too concerned with the outer edges (70% onwards). Nonetheless many eyepieces perform noticeably better than others even on axis but if you cannot get a good view in the centre then something is seriously wrong with the eyepiece if all other factors have been eliminated. By good I mean a clean view and not mushy. There are varying factors of good all the way up to exquisite.

At high power and if you have tracking and if looking at a small target then the centre is all you need to be concerned about. If no tracking then it’s nice to have a well corrected large apparent field so that you don’t have to nudge the telescope as often.

Eyepieces are very personal and what one person will enjoy and recommend based on their observing experience, equipment and eyes will not necessarily be the same for another person, their equipment and their eyes. If possible go to a star party and look through as many eyepieces as possible in similar telescopes to your own to get a feel for what works well and what you like.

I found this link reviewing the ES 4.7 vs Pentax 5mm that you may find interesting. See https://stargazerslounge.com/topic/2...pentax-5mm-xw/

Not sure if the Meade 4.7 UWA is identical to the ES 4.7/82. 4.7mm would give you 320x which will be pushing it a lot on most nights as would 5mm at 300x. However given good seeing 300x is very doable in a good 12” telescope. I think your other option of 6.5mm may be more useful more often. I’ve not used the Morpheus so cannot comment on its performance.

It will come down to how much you want to spend and on what focal length you want to spend that on first. 13/9/7/5 or 13/10/8/6 or combination thereof would all be useful focal lengths with your telescope at the mid to high power end.

At the low power end it is just as interesting and for your telescope 31mm and 22mm in 82 deg is an option but this is where it starts getting expensive and that’s not even including 100 deg options. My first 2” low power eyepiece was a Celestron 32mm Erfle (many pronounce this as awful). It wasn’t awful until I used a 31mm Nagler and up until then it was perfectly adequate for many years, (only outer field is awful or poor in comparison). I still have it and occasionally use it but of course the Nagler wins on all accounts except weight which can be an issue especially with a Paracorr and I have sliding counterweights on my Newtonian for just that purpose.

Hope this was useful. Whatever you choose, enjoy!

Note you don’t have to spend a lot on eyepieces (or telescopes) to enjoy this hobby certainly not early in your journey and maybe not ever. Take your time and enjoy it!

Last edited by astro744; 02-12-2021 at 04:51 AM. Reason: Added last para and rephrased earlier sentence on Erfle.
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Old 02-12-2021, 08:34 AM
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I have Pentax XW7 and several Morpheus including the 6.5mm.

The Pentax is optically quite perfect but the eye relief is not as good as the Morpheus and I think the XW has a slightly narrower FOV. Eye position is a bit sensitive in the Pentax and not at all in the Morpheus.

Both are top notch eyepieces but if I had to chose one I would take the Morpheus. Part of a good view is the ability to comfortably hold a view without image blackouts, kidney beaning etc. The Morpheus does that so you get a more enjoyable overall view. The Pentax though is a wonderful eyepiece.

5mm might be not so useful though. That is getting pretty high in magnification.9mm may be better and have a nice 2X barlow for those occasional nights of good seeing where the 5mm would give a good view.
Even a 9mm is around 155X magnification.

I prefer my APM 9mm XWA (100 degree eyepiece) to any other eyepiece I have. A fraction of the cost of a Televue Ethos with 90%+ of the performance.

Greg.

Last edited by gregbradley; 04-12-2021 at 08:25 AM.
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Old 02-12-2021, 09:23 AM
Tropo-Bob (Bob)
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I support the idea of a medium power, used with a barlow.

I have a 12.5mm Morpheus and it barlows very well, even with a cheap shortie.
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Old 02-12-2021, 12:50 PM
Ryan101 (Ryan)
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Thanks for all the help.
I thought I had it narrowed down then you throw this barlowed medium power stuff at me haha.
I guess I'm leaning toward the 6.5 Morpheus at the moment but am wondering, is the Pentax at 300 power such a rare occasion to be able to use?

I've looked at the 4.7mm Meade in the classifieds at it seems they may be slightly inferior to the Pentax. I'm thinking that I might not be able to tell the difference too much just yet but I don't plan on making this kind of purchase again so I need to think about that.
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Old 02-12-2021, 02:31 PM
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AG Hybrid (Adrian)
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Pentax XW 5 mm has 20mm of eye relief with a AFOV of 70 degrees. The Baader Morpheus 6.5 is stated at 18.5mm with an AFOV or 76 degrees.

On those nights you can use the Pentax 5mm. You'll be glad you have it. You don't want to planetary observe with a barlow. Adding lenses and air to glass surfaces cause light scatter. Light scatter causes loss in contrast, and loss of contrast causes loss of detail.

I created a chart that calculates the functionality of my eyepieces. Every eyepiece will always be useful somewhere. One of my scopes is a 12' dob like yours but you don't always need to be looking through the 12' to appreciate a Pentax eyepiece.
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Old 02-12-2021, 02:57 PM
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OzEclipse (Joe Cali)
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Morpheus/XW5

I have a Pentax XW5. Beautiful (perfect) eyepiece as others have said. Also as others have stated, eye position and distance sensitive.

The link is to a detailed review by William Paolini about the Morpheus line. he has written the book, choosing and using eyepieces, part of the Patrick Moore, Practical Astronomy Series.

https://theskysearchers.com/app.php/...t-light-review

I have a Baader Hyperion 5mm and the Meade Series 4000 4.7mm. They are both very good value for money midrange eyepieces but it really depends on your budget. They are very reasonable performers for their price but naturally no competition to a Pentax XW5 which costs hundreds of dollars more. I have not looked through a Baader Morpheus so can't comment.

I use the XW5 more often with my 6" f6.9 (210x). I am still waiting for the night when the atmosphere is stable enough to use it in my 18" f5.5. I am not holding my breath. I have only owned the XW5 for 7 months and the 18" for 4 years. I have maybe a dozen nights over 4 years when I've been able to use a 7mm in the 18", 360X. As such, I'd expect that a 5mm in a 12"f5 (300x) would be infrequent in use but when the air is stable enough, you REALLY want to have that sort of magnification and not with a barlow.
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Old 02-12-2021, 03:40 PM
Ryan101 (Ryan)
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Once agai, thanks for all the help.
You've given me good insightful article to sift through.
I guess my last question would be, can any tell me what sort of eyepiece suits different telescopes better? It's great to get recommendations but I've searched everywhere and can't find any info on what type (not brand) of eyepieces work best for certain setups.
ie: plossl work best for fast Newtonian as apposed to multi layer wide angle or the like.
Or is this too broad a question maybe.
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Old 02-12-2021, 04:10 PM
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mura_gadi (Steve)
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You can also get barlows that have the lens unscrew to give you a x1.5 screw on barlow cap for EP's, and the x2 with the tube extender.

Using the x1.5mag would allow you a 9mm/6mm combo from the same eyepiece, which may be more useful. The ER from the x1.5 barlow will not be reduced by as much either.

I haven't tried any morpheus ep's, but the 9mm with a x1.5 barlow might prove a good ep for clear nights or superb nights. You still can go with the x2 barlow should conditions ever allow it.
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Old 02-12-2021, 04:22 PM
astro744
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Quote:
Originally Posted by Ryan101 View Post
Once agai, thanks for all the help.
You've given me good insightful article to sift through.
I guess my last question would be, can any tell me what sort of eyepiece suits different telescopes better? It's great to get recommendations but I've searched everywhere and can't find any info on what type (not brand) of eyepieces work best for certain setups.
ie: plossl work best for fast Newtonian as apposed to multi layer wide angle or the like.
Or is this too broad a question maybe.
I have always thought that Tele Vue eyepieces work well in any type of telescope and am yet to find a telescope design they do not perform in. I have used in refractors (f3.75, f5.4, f6, f7.5), reflectors (f4.5, f4.7, f5.5, f6.4, f7, f8), SCT, (f10) and Mak (f11) varying in apertures from 40mm to 406mm.

I can see you can buy a Morpheus for $390 and Pentax XW for $569. I'm sure from other user reports they are fine eyepieces. However you could get both used 13mm Nagler for $400 and Meade 4.7mm UWA for $180 (combined total just over the cost of the Pentax). You could always sell one or both of you dont like them.

The 13mm T6 Nagler is a small form factor 1.25" eyepiece that will fit any current telescope and in your telescope will give you 115x and 0.7 deg field which fits the full lunar disk in nicely with room to spare. M42 will also fit very nicely in this field. Barlow it for 230x on planets or planetary nebulae. (Get a Tele Vue 2x for a quality view or a 2.5x Powermate at a later stage for an effective 5.2mm eyepiece giving 288x). These sometimes come up used too.

The Meade 4.7mm is a bit on the short focal length but suitable on excellent nights. I have the ES 4.7mm/82, Nagler Type 1, 4.8mm and Nagler Type 6, 5mm. If the Meade 5000 series 4.7mm UWA is anything like the ES 4.7/82 then you will not be disappointed. I bought my ES used just to compare with the two Naglers. It's a close third in the 60-80mm refractors I've tried it in.

Is there a reason you want either 5mm Pentax XW or 6.5mm Morpheus? Why not a 7mm Pentax XW to give a more useful power more often.

I know too many options probably isn't helping.

Last edited by astro744; 02-12-2021 at 05:40 PM. Reason: Typo and grammar.
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Old 02-12-2021, 04:56 PM
Ryan101 (Ryan)
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I'm looking at those 2 because everything points to them being good. I can Barlow down the Hyperion 17mm to 8.5 already so I was looking for something with a bit more power than that.
As I've said it is a lot of cash for me so it needs to be something I'll be happy with for years to come especially once I have a bit more experience.
I have a Saxon 2 inch 2x ed Barlow. Is this one I can break down to 1.5x
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Old 02-12-2021, 05:52 PM
astro744
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If unsure hold your money and join an Astro society and Covid permitting go to as many star parties as you can. Only way to get to see lots of eyepieces and telescopes. Itís your money so donít feel pressured into spending on anything youíre not sure on. Once youíve looked through a few different eyepieces youíll have a better idea of what you like.
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