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The Warthog

Eyepieces - the very least you need.

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Hi, Thanks for posting, gives me some information to get down to four/five good eyepieces as the Mak 127 I've just purchased came with nine eyepieces 2mm to 20mm plus 2x Barlow.

Cheers,

Len

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Very interesting. Before I acquired more expensive eyepieces I found that the relatively inexpensive 15mm Kellner and the Barlow from a Celestron AstroMaster Kit worked very well in my 102mm Mak with its f 12.7 and 1300mm f/l. 

The Kellner was plastic barreled but had a huge field stop with a nice AFOV, far more than the 15mm Omni Plossl that I supplemented it with later. I got the Omni on sale for less than half price. 

15mm Celestron Kellner

Celestron%20Kellner%201_zpscb3vzjp9.jpg

Kellner and Omni Plossl 15mm

1.25%2015mm_zpsouybwjli.jpg

AstroMaster Barlow

Celestron%20AstroMaster%20Barlow_zpsya2y

With the Barlow I could turn the 87x magnification into 173x, a very useful mag for lunar and planetary observing with decent FOV and eye relief. I had a 32mm Celestron Plossl for the low magnification. I also had a 13mm Plossl and slightly later a 12mm Omni Plossl. None of them were particularly expensive. All in all it gave me a decent range of around 41x to around 216x magnification. 

These were perfectly good to great views of Saturn and the Moon.

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Mak the Night, Don't tell everyone, they'll all wan't one?

A strange fact but true, some of the cheapest and dare I say it, poorest  eyepieces for some folk will work extremely  well when  suited to a particular telescope having the right focal ratio.

I have some Plossl's that range from £10  and their image quality ( last time I looked, sometime back, due to this seasons weather so far ) is very good, in fact so good, I'm having to check some TeleVue Plossl's to believe my own eyes ( I believe the hype that TeleVue may be the best )  but I still have some issues with their Plossl range ( my last test, the TV came second best, yet I will test again under darker and more strict conditions )  and the yet  because cheapness and quality does not often go hand-in-hand, at the end of the day, its what satisfies the end user. But if it works and matches the scope to your liking, that's a result.

You have acquired some eyepiece that work to your liking and saved you possibly  a small  fortune in the process, that has to be a self pat on the back. It really does not have to be expensive to enjoy this hobby.

Edited by Charic

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Mak the Night, Don't tell everyone, they'll all wan't one?

A strange fact but true, some of the cheapest and dare I say it, poorest  eyepieces for some folk will work extremely  well when  suited to a particular telescope having the right focal ratio.

I have some Plossl's that range from £10  and their image quality ( last time I looked, sometime back, due to this seasons weather so far ) is very good, in fact so good, I'm having to check some TeleVue Plossl's to believe my own eyes ( I believe the hype that TeleVue may be the best )  but I still have some issues with their Plossl range ( my last test, the TV came second best, yet I will test again under darker and more strict conditions )  and the yet  because cheapness and quality does not often go hand-in-hand, at the end of the day, its what satisfies the end user. But if it works and matches the scope to your liking, that's a result.

You have acquired some eyepiece that work to your liking and saved you possibly  a small  fortune in the process, that has to be a self pat on the back. It really does not have to be expensive to enjoy this hobby.

That Celestron Kellner is pretty well made, although the plastic barrel lets it down I think. I believe it's difficult to apply paint blackening to plastic. The subjective lens is large (as you can see in the jpeg) and the field stop rivals a 32mm Plossl, or seems to. I got such good views of the Moon and Jupiter with it it inspired me to shell out on wide angle EP's. 

TeleVue Plossls are very well made, but I actually find the Celestron Omni Plossl 15mm easier to use than the TV 15mm with its 12-13mm eye relief compared to the TV's 10mm. 

15mm4_zpsugsblqjc.jpg

These are all 15mm except the end Celestron Plossl, which is 17mm. The Celestron 15mm and 17mm Plossls are nearly identical. Although when directly compared the 15mm gives a slightly bigger image as would be expected. The TeleVue at the extreme left gives the biggest and sharpest image yet has the smallest eye relief. The size of the Kellner's subjective lens is readily apparent. Its eye relief seems the same as the 15mm Omni. The Kellner has the biggest AFOV. Weird or what?

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I've got an odd selection - but that's because i got mine from a mix of places, either being given for free, bought new or second hand. Currently with my F/5 6" i've got a 6mm WO, 9mm unbranded that has a 66˚ field of view, a 17mm celestron plossl (worthless really), a seben 8-24mm zoom (surprisingly good), a 30mm vixen and a x2 barlow unbranded. Honestly, all are great barr the 17mm celestron plossl, it's just such bad quality compared to the others and has awful contrast when viewing. I did buy it second hand off ebay, however. The 6mm WO and 9mm I use for lunar and planetary which are fantastic and give good detail and contrast when barlow'd. The other 8-24mm and 30mm are the low power EP's I use for wide-field. I find the 30mm vixen great and it's really good for the price. The Seben 8-24mm zoom is fantastic until you get close to 8mm or 24mm, with this one i found it's best to stay between 10-20 which gives good contrast and nice stars. I almost always start with this one in the scope, and it's probably the one i use most often.

I'm not awfully bothered with great eyepieces, more interested in learning imaging so I suppose great quality, expensive eyepieces would be a waste for me. These ones are a lot better than the stock EP's that come with the scope but not as good as the higher-end, i think they sit nicely in the middle - except the 17mm plossl. i'm not sure why i haven't sold or thrown it out the window.

Edited by abodee2

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I've got an odd selection - but that's because i got mine from a mix of places, either being given for free, bought new or second hand. Currently with my F/5 6" i've got a 6mm WO, 9mm unbranded that has a 66˚ field of view, a 17mm celestron plossl (worthless really), a seben 8-24mm zoom (surprisingly good), a 30mm vixen and a x2 barlow unbranded. Honestly, all are great barr the 17mm celestron plossl, it's just such bad quality compared to the others and has awful contrast when viewing. I did buy it second hand off ebay, however. The 6mm WO and 9mm I use for lunar and planetary which are fantastic and give good detail and contrast when barlow'd. The other 8-24mm and 30mm are the low power EP's I use for wide-field. I find the 30mm vixen great and it's really good for the price. The Seben 8-24mm zoom is fantastic until you get close to 8mm or 24mm, with this one i found it's best to stay between 10-20 which gives good contrast and nice stars. I almost always start with this one in the scope, and it's probably the one i use most often.

I'm not awfully bothered with great eyepieces, more interested in learning imaging so I suppose great quality, expensive eyepieces would be a waste for me. These ones are a lot better than the stock EP's that come with the scope but not as good as the higher-end, i think they sit nicely in the middle - except the 17mm plossl. i'm not sure why i haven't sold or thrown it out the window.

It's a shame about your 17mm Plossl, maybe it is defective. The best EP's in the Celestron Eyeopener Kit were the 17mm and 32mm Plossls IMO. The 13mm wasn't bad but the 6 & 8mm were virtually unusable.

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Just ordered my first scope and I've been looking at possible EPs that I might buy once I've had a chance to get to grips with the basics. Does anyone have any experience of using the Celestron Omni series EPs? I've ordered an Astromaster 130EQ and, as far as I'm aware, the Omni EPs are the same fit and, more importantly, well within my budget. I'm only thinking about getting a couple of EPs plus a Barlow at some stage, but the range of brands and designs is mind-boggling!

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Hi.......for about £15 the Revelation Astro GSO 12mm  (search GSO) from Astroboot will, in my opinion,  better the Celestron supplied 10mm EP you have. The 20mm you have will be ok for now until you want to experience wider fields of view and longer eye relief.

I have some Revelation Astro's and their sharp and bright for my eyes. 

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Just ordered my first scope and I've been looking at possible EPs that I might buy once I've had a chance to get to grips with the basics. Does anyone have any experience of using the Celestron Omni series EPs? I've ordered an Astromaster 130EQ and, as far as I'm aware, the Omni EPs are the same fit and, more importantly, well within my budget. I'm only thinking about getting a couple of EPs plus a Barlow at some stage, but the range of brands and designs is mind-boggling!

I have the Omni 12.5mm and 15mm Plossls, plus the Omni 2x Barlow, they are very nicely made Plossl EP's with a generous eye relief on the 15mm. Eyepieces are usually 1.25" or 2" in barrel diameter. I'm pretty sure your AstroMaster has the 1.25" eyepiece focuser. There is even an AstroMaster Kit available, although the Omni EP's bought separately would be better.

AstroMaster%20Modified_zpsbcdd7urw.jpg

Above you can see the AstroMaster kit case where I have replaced the original contents with my two Omni EP's, a 17mm Celestron Plossl and a 20mm Celestron erecting eyepiece. You will very probably be given the same erecting eyepiece with your AstroMaster scope. It's predominantly for terrestrial use and has a plastic body. It can be useful though if the upside-down world of Newtonian telescopes is disorienting at first and I used to use an erector on my Newtonian sometimes to help me acquire targets.

Your AstroMaster has a focal length of 650mm, which means that if you place a 10mm eyepiece into the focuser you will get a 65x magnification. If you divide the focal length of the telescope by the focal length of the eyepiece it gives the magnification. The 20mm erector will give you 32.5x magnification. For sweeping star fields around 30x is OK, but for lunar or planetary observing you will want at least 65x and preferably twice that. You should see the rings of Saturn at 65x for example. 

You can double (or more) the magnification by using a Barlow lens which is placed into the focuser and the eyepiece then placed into the Barlow. 

Celestron%20Shorty%20Comparison_zpshppuf

Above, Omni and standard Celestron Barlow lenses. I think the Omni Barlow is well worth the money (although I did get a deal on mine lol).

The problem with Plossl eyepieces of much less than 13mm focal length is that you may have the magnification that you need but you will have a smaller field stop and field of view, which many find uncomfortable.

Which is why the only 10mm EP I use much is a Celestron Luminos wide angle. They can be around £100 though.

CelestronLuminos1box%20-%20Copy_zpsr4c2l

And 3/4 of a pound in weight! lol

As you increase the magnification the target will move in the field of view more quickly due to the Earth's rotation (Right Ascension), so a wider eyepiece field of view is easier to view the object in frame.

The 12.5mm Omni should give you a 52x magnification with the AstroMaster, which you could potentially double with a Barlow lens. The 15mm would only give you about 43x but again, you could double that with a 2x Barlow. You can even triple it with a 3x Barlow. 

I have a 130mm scope with a 900mm focal length and I would often use a 15mm EP placed into a 3x Barlow for planetary viewing with it.

I'd also look at the Omni 32mm Plossl as a low power sweep/search EP. I have a  Celestron 32mm which is more or less the same as the Omni (not as pretty lol), although I prefer my TeleVue 32mm these days, the Celestron is nice though. The large field stop/apparent field of view of these larger Plossls is very aesthetically pleasing for viewing star fields and objects like open clusters. 

Celestron%2032mm%20Plossl_zpswpe7hww0.jp

I hope this was some help.

http://www.celestron.com/browse-shop/astronomy/telescopes/astromaster-130eq-telescope

Edited by Mak the Night
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Thanks for the info. Talking of Barlows, what are the disadvantages of using the higher-powered types; if I used a x3 instead of a x5, would I lose sharpness and definition on certain objects?

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Thanks for the info. Talking of Barlows, what are the disadvantages of using the higher-powered types; if I used a x3 instead of a x5, would I lose sharpness and definition on certain objects?

You would run into the magnification limits put on us by viewing conditions / scope type.

Barlow lenses are not "magic bullets" - the constraints on what is useful magnification still apply I'm afraid :smiley:

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Thanks for the info. Talking of Barlows, what are the disadvantages of using the higher-powered types; if I used a x3 instead of a x5, would I lose sharpness and definition on certain objects?

TeleVue explain Barlows better than I could: http://www.televue.com/engine/TV3b_page.asp?id=52&Tab=_back

Like John says above, there are constraints with Barlows depending on atmospheric conditions and telescope specifications. With your 5.1" aperture AstroMaster you should get a decent maximum resolution at around 300x. With good optics you could get around 60x magnification for each inch of aperture on your scope (this only applies to scopes 6" or under). So as long as you don't exceed that rough rule of thumb with any combination of eyepiece/Barlow or other amplifier you should get a relatively sharp image. Conditions are important though and so is the angle of the target object. Objects low in the sky, particularly in the plane of the ecliptic, like the Moon and planets are viewed through many more kilometres of sky than objects nearer the Zenith. Thermal heat rising can also be a factor in distorting views of lower objects particularly. Due to the nature of the atmosphere it's well nigh impossible to get much more than 300x anyway and unless you actually live in low Earth orbit anything above 350x is unrealistic. In fact, I believe that although you may be able to exceed 350x with a big enough aperture you can't actually see any more detail, just a larger image.

My 10mm Luminos in a Barlow would give me 260x on my 102mm/4" Mak, with its 241x resolution limit, and Saturn looks impressive but a bit grainy with it (I live in the green belt so have little light pollution) so if I use the Luminos I tend to thread a Barlow element straight into the eyepiece magnifying by only 1.6x instead of 2x. 

LuminosPlusBarlowElement_zpspklz2xvr.jpg

Although I tend to prefer to use a TeleVue Powermate 2.5x combined with a 16mm T5 Nagler for those sort of magnifications these days. 

I have experimented with the Luminos with a 3x Barlow on my Newtonian although the result was a tad heavy!

rocketgrenade1_zpsoq2n1v5f.jpg

It gave me 270x magnification, although as I hadn't set up the clockdrive even with an 82° AFOV any target moved quickly out of frame.

The quality of Barlows varies considerably, I prefer the TeleVue ones but they can be expensive. My Powermate (not strictly a true Barlow) cost more than my Newtonian scope including mount, tripod and motor drive. The Celestron Omni Barlows are good, I'm not sure if they do a 3x Omni Barlow. With an AstroMaster 130 a 3x Barlow would be a great help to improve magnifications with longer focal length EP's.

I can't recommend the TeleVue 3x enough if you are worried about quality of viewing. It really is superb.

http://www.telescopehouse.com/cgi-bin/sh000001.pl?REFPAGE=http%3a%2f%2fwww%2etelescopehouse%2ecom%2findex%2ehtml&WD=televue%20barlow&PN=TeleVue_3x_Barlow_1_25__%2ehtml%23aBLW_2d3125#aBLW_2d3125

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Interesting; I was wondering whether it would be worth getting a higher-powered Barlow for use with a 5 inch scope. That TeleVue looks just the ticket, though might have to do a bit of saving first (or stick it on me birthday list...)

Thanks very much for the info :-)

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Interesting; I was wondering whether it would be worth getting a higher-powered Barlow for use with a 5 inch scope. That TeleVue looks just the ticket, though might have to do a bit of saving first (or stick it on me birthday list...)

Thanks very much for the info :-)

You're welcome. There are probably really good 3x Barlows other than the TeleVue, but the quality both in build and optical is hard to beat IMO. The TV 3x Barlow was the first TeleVue EP I ever bought. It was worth the money.

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I, too, endorse the TeleVue Barlow in either 2X or 3X format. There are others available that have the ability to seemingly vanish in your optical-pathway. By this I mean that the Barlow doesn't dim or blur the image, which a lesser quality Barlow does in various degrees. This explains why I say the best Barlow's are invisible. I rarely plug TeleVue products as they may be too expensive for many people, and I don't wish to come across as being 'elitist.' But when buying a Barlow, I think it's important to steer people towards the only - or last - Barlow they'll ever need to purchase. Even if this means saving up or hunting for returnable cans & bottles to have enough to afford such.

In terms of should you get the 2X or 3X? All I know is that many people who have both agree the 2X is used far more often than the 3X. So if you can't afford both, then I'd be inclined to opt for getting the 2X first. In my own case - it is true that I rarely employ the 3X, the 2X seeing far more duty. I also love my 2.5X PowerMate, but the PowerMates' are actually a different animal altogether - acting as a Barlow in increasing the magnification, but doing so by a different method than Peter Barlow's design. The PowerMates deserve their own thread to hash out their wonders IMHO.

Enjoy!

Dave

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Just been gifted a set of Celestron Plossl eyepieces and filters (including a 2x Barlow) so now I just have to wait for the skies to clear... :-)

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Just been gifted a set of Celestron Plossl eyepieces and filters (including a 2x Barlow) so now I just have to wait for the skies to clear... :-)

Yeah, it's terrible having new gear with rubbish weather. Welcome to astronomy lol! If you've got the Celestron Eyeopener Kit (the one in the big silver shiny box) it's actually pretty good as a starter kit. I believe it's been through a few incarnations over the years but I liked mine. The 13mm, 17mm and 32mm Plossls are good quality and apart from the fact that they are a different colour seem more or less identical to the Omni range. The 6mm and 8mm have the same quality but many find them difficult to use, although I thought the 8mm wasn't bad considering the limits of eye relief and field stop on such a short focal length. The Barlow is basically the same as the Omni equivalent although you can't remove the lens element like on some Celestron kit Barlows. Optically it's fine. There are seven Kodak Wratten colour filters consisting of an #80A Blue, #58A Green, #56 Light Green, #25 Red, #21 Orange, #12 Yellow and a #0.9 Moon Filter.

This PDF may be useful: http://sas-sky.org/wp-content/uploads/2011/09/SAS-The-Use-of-Astronomical-Filters1.pdf

I found the orange useful for daylight lunar viewing as it turns the blue sky dark. The Moon tends to resemble a Terry's Chocolate Orange though lol.

Like this (by courtesy of the Virtual Moon Atlas and PhotoFiltre 7):

MARE%20IMBRIUM2_zpsjsimqbon.jpg

The Eyeopener Kit looks like this new:

ccase2_zpsutunvl84.jpg

The ABS case is aluminium framed and looks 'Jason Statham' hard. 

BigandLittleDumpy_zpsjpqwrzvr.jpg

I still find the case useful, albeit modified a bit. 

Edited by Mak the Night
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Sadly I've had to give the EP set back (my dad gave it to me because he thought his scope was broken beyond repair, but he's now discovered otherwise; I don't mind, though, as it's given me all the info I need regarding which magnifications work best with my scope and it also means he and I can do some stargazing together.)

Looks like I'll be purchasing some of the Celestron Omnis and a moon filter to start me off again! :-)

Oh and I love the chocolate orange effect in that photo ;-)

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Sadly I've had to give the EP set back (my dad gave it to me because he thought his scope was broken beyond repair, but he's now discovered otherwise; I don't mind, though, as it's given me all the info I need regarding which magnifications work best with my scope and it also means he and I can do some stargazing together.)

Looks like I'll be purchasing some of the Celestron Omnis and a moon filter to start me off again! :-)

Oh and I love the chocolate orange effect in that photo ;-)

Well, you can't go wrong with the Omni Plossls, they're pretty good. I never use a Moon filter and I view the Moon a lot. I find after a while I can adapt to the brightness and if I'm lunar viewing I usually don't try to observe anything else. Where I live in the greenbelt, as light pollution isn't a real problem, a Full Moon tends to light up the whole viewing area (aka my back lawn lol) anyway often negating the need for a red-light torch. I usually lunar observe with my 102mm Mak so when I get a 9.25" SCT early next year I may need a filter with the bigger aperture. I'm also planning on acquiring binoviewers essentially for lunar and planetary observing so I've been thinking about filters in general. If I were you, I'd invest in some decent eyepieces first and look at filters later. 

Oddly, I really used to like viewing the Moon with the 15mm Kellner from the AstroMaster Kit.

Celestron%20Kellner%201_zpscb3vzjp9.jpg

You can see it has a large subjective lens and it also had a large AFOV and field stop, which I believe is often the case with Kellners. I think you can pick the AstroMaster Kit up for around 50 quid. The Barlow is good quality and has a removable element. The kit also has a Moon filter and a red and a blue Kodak Wratten filter. 

Celestron%20AstroMaster%20Barlow_zpsya2y

I'd get the Omni Plossls and a Barlow though rather than the AstroMaster Kit. 

I so want a Terry's Chocolate Orange now lol!

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The 20mm erecting eyepiece usually supplied with AstroMaster telescopes seen here to the right of the Kellner.

Celestron%20Kellner%20and%20Erector_zpsv

I'm not sure what type the erecting eyepiece is but the Kellner differs from the Plossl in design.

EyepiecesDiagram%20-%20Copy_zpscv0gvsgi.

EyepiecesDiagram_zps8mtng6u4.jpg

This probably explains its wider field of view. 

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The Kellner usually has a field of view of around 45 degrees. You can get them a bit wider but the correction goes downhill off axis quite quickly. They work best in scopes of F/10 or slower. Plossls are generally better corrected up to 50 degrees and work better in faster scopes than Kellners do.

The erecting eyepiece will have an additional lens set in the barrel to flip the image around to match the view that our eyes see. They don't work well for astronomy purposes.

The Celestron Omni plossls are OK in quality terms. About the same as the Skywatcher SP plossls. The Vixen NPL plossls are better quality I think but they cost a little more as well.

The field of view of an eyepiece is determined by the diameter of the field stop rather than by the diameter of the lenses. You can have a very wide field stop but if the optical design of the eyepiece is not well corrected off axis the outer parts of the field will not be particularly nice to look at !

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I think it was the field stop of that Kellner (if it is a true Kellner and not modified by Celestron somewhat) that intrigued me the most. It seemed so wide compared to the Plossls I had. It's objective lens does seem too far from the end of the barrel compared to the diagram to be a Kellner even though Celestron describe it as one.

Kellner%20Objective_zpspgtss6rf.jpg

I'm pretty sure the Celestron erectors are intended for terrestrial use, although I used mine for planetary viewing in a Newtonian once or twice, albeit combined with a TeleVue 3x Barlow!

Edited by Mak the Night

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Been recommended to get a Plossl 25mm eyepiece, can anyone tell me where is the best place to get one from? Or should I just order from the likes of EBay/Amazon?

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Been recommended to get a Plossl 25mm eyepiece, can anyone tell me where is the best place to get one from? Or should I just order from the likes of EBay/Amazon?

First Light Optics do the Skywatcher SP plossls at £20 for the 25mm:

http://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-sp-plossl-eyepieces.html

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I think it was the field stop of that Kellner (if it is a true Kellner and not modified by Celestron somewhat) that intrigued me the most. It seemed so wide compared to the Plossls I had. It's objective lens does seem too far from the end of the barrel compared to the diagram to be a Kellner even though Celestron describe it as one....

The field stop diameter of an eyepiece will increase as it's focal length increases so a 25mm Kellner (or similar 3 element design) will have a larger diameter field stop than, say, a 15mm Plossl. The Plossl will still have a larger apparent field of view through.

The 25mm Kellner type eyepieces supplied as stock items are often labelled "Super Wide Angle" or similar because their field stop is a little wider than the a normal Kellner would be. So you see a little larger apparent field of view even though it's not going to be that well corrected, especially in a faster focal ratio scope.

These are low cost eyepieces though (you can get them for £5 used) so thay don't do too badly considering that and they do get you started :smiley:

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