43 replies to this topic

[Naja keravnos]

Hi, I recently bought my first telescope, an Apertura AD8 (this forum was a huge help in deciding, thank you to everyone!). Anyway, while this is supposed to be a fantastic scope, basically all the reviews I read were a bit disappointed with it's high-power eyepiece, a 9mm Plossl. They recomend replacing it with a Goldline or a Paradigm or something else because of it's short eye relief. I have two questions about this:

 

1) Is what makes the eyepiece disappointing just it's short and uncomfortable eye relief, or is the quality also low?

2) Is the eyepiece so bad that it will spend most of it's time sitting in the rack, or is it good enough for the beginning and replacing it is more of an upgrade? I'm on a tighter budget, so I want to know if to view with higher power I have to buy an additional eyepiece, or if I can be content with this one for the time being.      

 

Please note that I really have no experience and am basing this on what I heard; I apologize if this eyepiece is actually good and I just sound like an obnoxious critic. 

 

Thank you for your help!

Edited by Naja keravnos, 24 January 2021 - 12:19 PM.

[wrvond]

Since it's part of the package, try it out for yourself and decide whether you like it or not. Use your own judgement. It's very easy to get hyper critical of equipment on the forums.

[Taosmath]

Plossl's are usually decent eyepieces if they are made properly.  They are reasonably sharp but the eye relief they offer decreases significantly as the eyepiece focal length reduces. If I remember correctly the eye relief is about 0.57* the focal length.  So a 9mm plossl has an eyepieces of about 5mm.

 

Many people find this uncomfortably short.  You may not.

 

Just try it.  If you can handle the eye relief then the plossl should be absolutely fine for your scope and you can probably use it happily until the bug comes a long to upgrade.

 

Try it, use it and I hope you have fun!

 

Oh and +1 on wrvond's comment above about people on equipment sites getting hypercritical

Edited by Taosmath, 24 January 2021 - 11:01 AM.

[Jim Davis]

I have never used that eyepiece, but it is similar to other plossls. I think the issue here is 2 things. A 9mm plossl has short eye relief. Also, plossls are not wide field eyepieces. Since you scope is manually tracked, it will make it difficult to keep the object in the small field of view.

[DouglasPaul]

Have you used it? Some of the higher power eyepieces that came with telescopes I have bought are not usable, others are. If you can use it, do so. Give it some time, if you decide it just doesn't work for you then by all means find a affordable upgrade.

[Tangerman]

I got the AD10 package a bit more than a year ago and found the 9mm eyepiece that came with it to give nice, crisp images. It's certainly not as comfortable to use, but I do use mine on occasion. Neither eyepiece that comes with the package is bad in my opinion, and I recommend using them before deciding on other eyepieces to get. There's plenty to see with just those two. 

[ngc7319_20]

If I read the scope specs correctly, this comes with a 30mm 2" wide field, and a 9mm 1.25" Plossl.  I don't know many serious observers that would get by with just those two eyepieces.  I think sooner or later you will want to expand the eyepiece range.  Maybe something like an 12mm and 18mm (Paradigms?) and a 2x Barlow.   You might save some $$ by buying second hand.

 

I don't have the 9mm you mention, but is does say "fully multi-coated" which sounds good.  And blackened lens edges.  The 6mm eye relief is very short -- whether it works for you I can't say.   Whether there is good quality control -- I don't know.  It might be fine.

 

https://www.highpoin...e-125inch-a-pl9

Edited by ngc7319_20, 24 January 2021 - 11:38 AM.

[JamesDuffey]

I agree with wrvond, use the 9mm eyepiece provided with your scope and decide if it is adequate for you. It is probably good. You will probably get many enjoyable hours of observing from it. 40 years ago, these were premium eyepieces. The short eye relief is a personal thing and usually more objectionable to those who have observed with a long eye relief eyepiece than to someone who has not done much observing. So try it, you may get along with it fine. 

 

If you are going to invest in another eyepiece, I suggest that you look at another focal length as a better investment. There is a pretty big jump between the magnification of the 32mm fl eyepiece, 32.5x, and the magnification produced by the 9mm, 133.3x. That is a big jump and you can miss a lot in between. So, I would suggest getting a 15mm eyepiece for 80x, which gives your three magnifications spaced 50x or so apart. You have been looking at the Gold Line eyepieces, and a 15mm Gold Line eyepiece at $35 is a better observing choice than getting another 9mm eyepiece. If you want to spend a bit more, the 15mm Paradigm/Starguider is a better choice, but it costs more.

 

When building a useful set of eyepieces, it is almost always a poor choice from an observing standpoint to replace an eyepiece with one of the same focal length until you have filled in other gaps. So I would say that your 32mm Superview, a new 15mm eyepiece, and your 9mm Super Plössl will set you up for good observing sessions for cloudless nights for a long time.

 

Stand by for the zoom eyepiece enthusiasts. That is another choice. 

Edited by JamesDuffey, 24 January 2021 - 12:09 PM.

[Naja keravnos]

Thank you for the insightful advice, I really appreciate it. You've definitely given me things to think about.  

I have definitely considered waiting to try the Plossl first and see how comfortable I am with it. However, since where I live astronomical equipment isn't very accessible (and very expensive if it is), and especially because of the pandemic, it might be several months or more after the scope arrives before I can obtain more eyepieces. So just in case, I want to make sure that I'm able to enjoy the full capacity of my telescope (i.e. the planets and such) when it arrives. Sorry that I didn't mention that earlier. 

 

Thank you again, and clear skies! 

Edited by Naja keravnos, 24 January 2021 - 12:37 PM.

[argonbeam]

I have the same AD8. Comments on the 9mm below. The GSO 30 is just fine for learning the skies. Many have commented on the edge issues, but they don't bother me too much. That being said, the 35mm Panoptic I picked up is an upgrade, as it should be for the price difference (I got mine used though, saving some cash). The 9mm is fine, but with the manual scope it was hard for me at first to keep the image in view without being wobbly and blurring the image, etc. Now that I'm more an 'advanced beginner' it's not as hard. However, I found the wider FOV eyepieces are just easier to use and frame more of the open clusters, M42, etc, that I enjoy viewing, so the 9mm Plossl just doesn't get used much. It's not inherently bad though. I second buying used, as can turn around and sell if the EP doesn't work for you, minus the hassle of shipping and usually a small loss of money with shipping, fees, etc, which I consider a 'rental' fee. Eventually we can have star parties again and get to try out EPs with other enthusiasts to have the ability to try a bunch of different setups.

Edited by argonbeam, 24 January 2021 - 01:43 PM.

[FlyingV74]

A few months ago I purchased the Zhumell Z8 (same scope as the AD8). I was able to use the 9mm Plossl to view Jupiter and Saturn while they were still higher in the sky. I saw clouds bands and the red spot on Jupiter. I saw a moon transit on Jupiter. I also saw the Cassini division in Saturn’s rings. And while I don’t have any high end, wide view eye piece to compare to, I found the view with the 9mm to be fine. The environment has always been my limiting factor.

For my first eyepiece purchase, I bought a low cost 7-21mm Svbony zoom. The other night I was using it along with a low cost 2x Barlow to view the moon. It was nice being able to zoom out, find an object, and then zoom back in. I was zoomed all the way in and viewing a crater with a little mountain in the middle. I don’t know the name of the crater. I’m still working on that aspect of my viewing. I would highly recommend a zoom eyepiece.

[argonbeam]

A few months ago I purchased the Zhumell Z8 (same scope as the AD8). I was able to use the 9mm Plossl to view Jupiter and Saturn while they were still higher in the sky. I saw clouds bands and the red spot on Jupiter. I saw a moon transit on Jupiter. I also saw the Cassini division in Saturn’s rings. And while I don’t have any high end, wide view eye piece to compare to, I found the view with the 9mm to be fine. The environment has always been my limiting factor.

For my first eyepiece purchase, I bought a low cost 7-21mm Svbony zoom. The other night I was using it along with a low cost 2x Barlow to view the moon. It was nice being able to zoom out, find an object, and then zoom back in. I was zoomed all the way in and viewing a crater with a little mountain in the middle. I don’t know the name of the crater. I’m still working on that aspect of my viewing. I would highly recommend a zoom eyepiece.

I have that zoom too, and agree it's good for planets and exploring what focal length seems to be best for certain objects. FOV quite narrow though. The price can't be beat however! So definitely worth acquiring to try out.

[KBHornblower]

I am really dated by the frequent adverse remarks about the narrow field of view of Plossls.  They are luxuriously wide compared with the Ramsden I started with as a kid back in the late 1950s.

 

I concur with the recommendation to use what comes with the telescope for a while before replacing it with something of the same focal length.  Get well acquainted with what you have, and you will develop the skill that will help your judgment on possible upgrades.

[BlueTrane2028]

For me, with a manually operated mount, be it Dob or equatorial, I want the most drift time possible before having to move the telescope. Therefore, field of view wins.

Plossls are 52*. Gold Lines are 66*. Right there, you gain more of the sky at a given magnification. Jump to an 82* eyepiece and it’s better yet.

Can you get an excellent view with a Plossl? Yes. I own about every focal length made in 1.25” barrel. They even see use from time to time. Are they my first choice? No.

Edited by BlueTrane2028, 24 January 2021 - 01:57 PM.

[BlueTrane2028]

I am really dated by the frequent adverse remarks about the narrow field of view of Plossls.  They are luxuriously wide compared with the Ramsden I started with as a kid back in the late 1950s.

 

I concur with the recommendation to use what comes with the telescope for a while before replacing it with something of the same focal length.  Get well acquainted with what you have, and you will develop the skill that will help your judgment on possible upgrades.

For sure. My first Astro telescope in was/is a 60mm f/15 with a .965 focuser and Ramsden and Huygens eyepieces. They were badly made even for their type and a big part of why I gave up trying to look through it, much to my parents chagrin. 
 

I pull that old scope out every now and then. With a set of 1.25" Plossls by way of a conversion diagonal, its very usable. I’d have undoubtedly spent a lot more time with it had I had those eyepieces back then.

 

Again, Plossls can provide fabulous views, they just aren’t my first choice. I usually bring them out with the small refractors when I’m feeling a sort of what could have been nostalgia. 

Edited by BlueTrane2028, 24 January 2021 - 11:51 PM.

[sevenofnine]

I still use plossl's from 32mm-12mm. mostly in my already narrow view C-90. They work fine because that scope is good for quick peeks at planets, lunar, solar and bright DSO's. I tend to match better eyepieces with my larger scopes. A wider FOV eyepiece works better in my manual tracking Dob. The eyepiece is easier to look through too due to it's larger size. There are quality issues too. The generic 32mm plossl is nowhere near as good as the ES 30/52 even though the specs are similar. So there are lots of reasons to upgrade to better eyepieces. They are fine for awhile but as your observing skills improve you will want to replace plossls with better glass.    

[vtornado]

I have a  lot of Chinese plossl's with name brands on them, like Meade, Celestron and Orion.   If well executed they are decent eyepieces.   There are dogs out there.   I'm sure there is no QA done on them.  They come off an automated line, and boxed and sold.  I have some televue plossl's and they are sharper  than the cheap counterparts, but not "oh my gosh" better.

Edited by vtornado, 24 January 2021 - 05:28 PM.

[spaceoddity]

Most of the mass market cheap plossl's are of acceptable quality and give good views. I wouldn't want to go any shorter than 9mm though as the eye relief gets extremely short and the higher power means shorter drift times in an undriven scope. If I was you I wouldn't worry about replacing the 9 for now. I'd look at something in the 6-7mm range for higher powers and a mid power eyepiece somewhere inbetween the 30 and the 9(probably 15-20mm) as your next ep purchases. No rush, the 30 and 9 will be good to get you started.

[Tony Flanders]

As far as drift time is concerned, I have no issues whatsoever using a 9-mm Plossl in an 8-inch f/6 Dob. Now if you were talking about a 5-mm eyepiece, or using the 9-mm Plossl together with a Barlow, or using it in a scope with a much longer focal length, I might feel differently.

 

Let's do some arithmetic. An 8-inch f/6 has a focal length around 1200 mm, yielding about 133X with a 9-mm eyepiece. Assuming a 50-degree apparent field of view, that gives you a true field of view around 50/133 ~= 0.38 degrees, or 23 arcminutes.

 

Celestial objects on the equator move through your eyepiece at a rate of 15 arcminutes per minute of time, and all other objects move slower. That means that in theory an object can stay in the field of view of the 9-mm Plossl for 23/15 ~= 1.5 minutes of time. Given that it's vary hard to position a scope so that the object drifts right through the center of the field of view, one minute is more realistic.

 

Now depending on your point of view, one minute is a very long time or a very short time. I think most people would find that when scrutinizing one particular object in a conscious way, one minute is quite long. Regardless, it takes only a couple of seconds to move a Dob. To be generous, let's say that it takes 6 seconds to position it just right and let any vibrations settle. That means that you have only 10% downtime due to moving the scope. And you probably want to take a break every minute or so just to rest your eyes anyway.

 

Personally, I find the short eye relief of a 9-mm Plossl to be more of an issue than the modest field of view. However, I do find the eye relief to be acceptable -- barely. For me, unacceptable starts around a 7-mm Plossl.

 

So if it were me, I certainly wouldn't rush out to replace the 9-mm Plossl. In the fullness of time, you're likely to end up with a whole different set of eyepieces offering both better eye relief and wider apparent field of view. Which may or may not include a 9-mm eyepiece. But rather than try to guess what eyepieces you're going to want, take it easy an buy them as the need arises.

[Jon Isaacs]

Thank you for the insightful advice, I really appreciate it. You've definitely given me things to think about.  

I have definitely considered waiting to try the Plossl first and see how comfortable I am with it. However, since where I live astronomical equipment isn't very accessible (and very expensive if it is), and especially because of the pandemic, it might be several months or more after the scope arrives before I can obtain more eyepieces. So just in case, I want to make sure that I'm able to enjoy the full capacity of my telescope (i.e. the planets and such) when it arrives. Sorry that I didn't mention that earlier. 

 

Thank you again, and clear skies! 

 

 

As others have said, a 9 mm Plossl is a good, solid eyepiece. The eye relief is definitely on the short side but it's very useable.  

 

I can see your situation from two points of view:

 

- You're getting a new scope, enjoy it, use it, figure out what you want. 

 

- You're getting a new scope, you would also like to have a set of eyepieces that allow you to use the scope closer to its full potential. 

 

It seems that with the long wait time, you are considering the second option. I think this ,makes sense.  It is partly a decision that depends on your budget as well as your general attitude.

 

Earlier, someone recommended the 12 mm and 8 mm Astro-Tech Paradigms. These are $60 , 60° eyepieces with a comfortable 13mm of eye relief.  I like these eyepieces. I have a set of them. I also have a full set of much more expensive eyepieces but the Paradigms do a nice job.

 

With the 2x Barlow, you would have:

 

30mm: 40x

12 mm 100x

8 mm: 150x

12mm Barlow 200x

8 mm Barlow 300x.

 

With the GSO type Barlow, you can unscrew the optics, thread them to the eyepiece for a 1.5x Barlow.  With the 8mm,  that would be 225x.

 

There's a gap between 40x and 100x, you could fill that with the 18 mm.

 

Jon

[Rwhit]

Hey! I also ordered the AD8 a few weeks back and have done a bunch of research into this very topic. I settled on the approach that people here are recommending: Just wait and see. There is no rush and you may find that for a beginner, the 9mm eyepiece is perfectly acceptable. I've seen a few people in my internet research journey who have used the stock eyepieces for a year or two before moving on to something else. 

 

Of course, that was my approach until I found cloudy nights classifieds...After doing a bit more digging into it I saw a Celestron zoom eyepiece pop up for 65$ on the classifieds and went for that. It covers from 8-24 mm and according to everyone's reports, has decent view quality. For that price, and for where I am experience wise, I figure that will last me for a long while. I'll likely want to upgrade to wider field of view eyepieces eventually, but couldn't beat that price for all of those options in one eyepiece. You may want to look into that. 

 

Good luck and clear skies!

[MaknMe]

I have a 9mm Nagler (type 1) and an older Meade 9mm Plossl. The Nagler has a a wider FOV and more eye relief, but there is little difference in the sharpness of the stars or planets.

[aeajr]

Hi, I recently bought my first telescope, an Apertura AD8 (this forum was a huge help in deciding, thank you to everyone!). Anyway, while this is supposed to be a fantastic scope, basically all the reviews I read were a bit disappointed with it's high-power eyepiece, a 9mm Plossl. They recomend replacing it with a Goldline or a Paradigm or something else because of it's short eye relief. I have two questions about this:

 

1) Is what makes the eyepiece disappointing just it's short and uncomfortable eye relief, or is the quality also low?

2) Is the eyepiece so bad that it will spend most of it's time sitting in the rack, or is it good enough for the beginning and replacing it is more of an upgrade? I'm on a tighter budget, so I want to know if to view with higher power I have to buy an additional eyepiece, or if I can be content with this one for the time being.      

 

Please note that I really have no experience and am basing this on what I heard; I apologize if this eyepiece is actually good and I just sound like an obnoxious critic. 

 

Thank you for your help!

I didn't find anything wrong with that 9 mm as compared to other Plossl eyepieces in that size range.  So don't hesitate to use it and enjoy it.  However, when time and budget allow, you will likely follow the trend toward wider AFOV eyepieces.  But, until then, use it and enjoy it. Fill in at other sizes, where you feel the need, and keep using the 9 mm till you are ready to upgrade to something else, if ever.

 

I have the AD12.  Came with the same 30 mm and 9 mm eyepieces.  I tried them and they work fine.  However, I have a full set of eyepieces so these went with my Orion XT8 when I sold it.  Both of the eyepieces are GSO.   GSO makes the scope too.  Many of the Plossls on the market are rebranded GSO Plossls. 

 

Understanding Telescope Eyepieces

https://opticsaide.c...-for-telescope/

 

 

Plossls are good eyepieces but the eye relief gets fairly short once you get below 12 mm.  I have Plossls all the way down to 6.4 mm and they are all useable and provide good images.  However, the trend is toward wider AFOV eyepieces so people will tell you to replace Kellner and Plossl eyepieces immediately.  But that doesn't make them optically bad, it just means that there are many other choices available that provide a wider field of view and more eye relief. 

 

Plossls are very good eyepieces  – Good discussion
https://www.cloudyni...s/#entry8285208

 

 

Eyepiece Designs -  This is the one I turn to when I am trying to understand or explain the differences between the various designs.  There are many different designs, Many are named
for their original designer, such as Huygens, Ramsden, Kellner, Plossl, Konig, Erfle, Branden and Nagler.
http://www.chuckhawk...ece_designs.htm

Edited by aeajr, 25 January 2021 - 11:01 AM.

[Bigal1817]

Hi, I recently bought my first telescope, an Apertura AD8 (this forum was a huge help in deciding, thank you to everyone!). Anyway, while this is supposed to be a fantastic scope, basically all the reviews I read were a bit disappointed with it's high-power eyepiece, a 9mm Plossl. They recomend replacing it with a Goldline or a Paradigm or something else because of it's short eye relief. I have two questions about this:

 

1) Is what makes the eyepiece disappointing just it's short and uncomfortable eye relief, or is the quality also low?

2) Is the eyepiece so bad that it will spend most of it's time sitting in the rack, or is it good enough for the beginning and replacing it is more of an upgrade? I'm on a tighter budget, so I want to know if to view with higher power I have to buy an additional eyepiece, or if I can be content with this one for the time being.      

 

Please note that I really have no experience and am basing this on what I heard; I apologize if this eyepiece is actually good and I just sound like an obnoxious critic. 

 

Thank you for your help!

Congrats on your AD8 purchase.  You're going to love it, I love mine.  I chose to replace the 9mm but not because it was a bad eyepiece.  The AD8 is my 2nd scope and so I have begun building my eyepiece collection.  You may choose to replace your 9mm too.  Please don't feel in any rush to do so.  The 30mm 2" and the 9mm 1.25" are all the eyepieces you will need to enjoy the night sky for a long time.  

[Crankyanken]

I can't use the 9mm due to the eye relief, but the 30mm is a very good eyepiece.  I highly suggest a 2" barlow, this will add more magnification levels to one eyepiece.  With just one eyepiece you would have 40x, 60x, 80x.