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Explore Scientifc 82 degree eyepiece range - First light report

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Explore Scientific Eyepieces – First impression

Recently I purchased a range of Explore Scientific 82 degree eyepieces. I purchased the 4.7mm, 6.7mm, 8.8mm, 11mm, 14mm and the 18mm. It has been around a month since purchase now and I have had only three or four good evenings or about 10 hours in which to try these eyepieces out. The conditions across the nights have varied with some nights of good seeing and others of good transparency but not both at once. I have not had the chance to use any of the eyepiece on the moon yet so can’t comment specifically on their performance on the moon. Until now I have yet to post any kind of report because it has simply taken me this long to get any length of time at the telescope with each eyepiece to warrant any kind of first light report.

The telescope I used was a 10” Newtonian with 1200mm focal length (F4.7) although I also used them all in a 6” 5 Newtonian as well my impressions here are from the larger scope alone. I do not own any form of coma corrector so my impressions are based on the use of the eyepiece within the telescope only.

I have never observed with any other astronomer so have only my own impressions to go on. As such the only kit I have any experience with I have had to purchase myself. I can’t therefore offer any subjective or objective opinion or comparison with other brands.

The 11mm that was delivered was part of the older range of 82 degree eyepieces. It has seen very little use because I am returning it for a replacement with the new 11mm. This eyepiece is no longer for sale so I have excluded it from this report.

So onto the eyepieces:

Explore Scientific 4.7mm 82° AFoV

Weight: 216g Eye relief: 14mm

255x 0.32° TFoV 0.99mm Exit pupil

This is the shortest focal length of this range of eyepieces. My first impression of this eyepiece is its size. It feels little more in the hand than a 32mm Plossl. It’s hard to believe this slim, tall eyepiece whose waist is barely wider than the 1.25” barrel it sports can deliver the stated 82 degrees AFOV. It has a nice rubber grip around the waist which works well in the cold to give you the confidence that you aren’t going to drop it and also doesn’t get cold like an all metal eyepiece would. The eyecups throughout the range are tight fitting with a rubber cup on the field stop end and a plastic cap on the eyeglass end which fits tightly to the rolled down rubber eye guard. The design is such that when you remove the eye glass cup it automatically pulls up the eye guard for you. The weight, in my opinion, is light but the eyepiece feels well-built despite this. The eye glass end offers a nice portal to look through at 16mm diameter.

In use the eyepiece delivers well. I found the eye relief quite tight however. The eyeglass is recessed only about 3mm from the top face of the eyepiece so you feel in danger of brushing your eye lashes on the glass although I have yet to do this. I can’t see the entire field with the eye guard rolled up. With the eye guard up the field is cropped by around 10% and a gentle push into the rubber reveals all. Strategic placement of the eyecup in the groove of your eye socket allows good positioning of the head and the entire field to be revealed however I found myself naturally rolling the guard down for extended viewing. I found the eyepiece very resistant to optical defects like kidney beaning/blackout with severe misplacement of the head required to introduce any such issues. The eyepiece in my scope delivers approximately a 1mm exit pupil which for me is the lowest I like to go before I see floaters and the quality of the image degrades to the point I find it unpleasing. My sole use of this eyepiece has been planetary with both Jupiter and Saturn being observed. The backgrounds are absolutely jet black across the entire field at this magnification.

Jupiter, in moments of good seeing, showed exceptional clarity and detail unlike anything I have seen to date. I observed very clearly the great red spot, many cloud bands including spectacular detail within the bands themselves (eddies and seagulls). I also caught a moon in transit. The moon’s shadow cast a clear, well defined black spot against the colour of the face with no seepage of colour from the planet’s disc into the shadow. Saturn offered up good detail on the rings with the Cassini Division visible from centre to field stop, I also observed the shadow of the ring on the disc and colour bands on the disc.

Perhaps unsurprisingly this eyepiece required some patience at this magnification waiting for moments of good seeing. In between good seeing the view differs drastically with Jupiter turning into a hazy blob with only two to four bands present and not much else.

I noticed, particularly on Jupiter being the brighter of the two objects, that false colour is present from about 60% out from the centre with a brown fringe forming on the trailing edge. At about 75% out a light blue hue appears on the leading edge ever so slightly which deteriorates to the field stop. Focus was maintained to about the final 5%. The primary cloud bands and 2 minor ones only were visible at field stop. This may have been compounded by a change in seeing conditions as I was not specifically testing for this at the time.

My conclusion is this is a punchy little eyepiece that performs well for its price. I was of two minds whether or not to purchase this one given I expected to use it quite little but since owning it I have used it a lot more than I thought I would. It always goes in first on a planet to assess the quality of the sky rather than opting for a lower magnification and working up to it. The tight eye relief may need to be worked with as I don’t want to leave any eyelash marks on the eye glass. The false colour, although evident, is not overly distracting and I expected some aberrations at the field stop at this price point.

Explore Scientific 6.7mm 82° AFoV

Weight: 229g Eye relief: 14mm

179x 0.46° TFoV 1.42mm Exit pupil

This eyepiece physically is almost identical to the 4.7mm. It has the same incredibly slim form and exceptional build quality of its baby brother, is almost the same weight and is only a fraction taller. The eyeglass is equally recessed at 3mm but offers a slightly larger portal at 19mm.

In use I found this eyepiece more comfortable than the smaller 4.7mm. The eye relief is rated the same as the 4.7mm but in practice it feels more forgiving. I can only view the entire field with the eye guard rolled down. The eyepiece is much more tolerant of poor seeing conditions and offers pleasing views on both Jupiter and Saturn alike. The backgrounds appear as inky black as the smaller eyepiece. The level of detail viewed with the 4.7mm is almost evident as well at this magnification and may even be as visible to a more discerning observer than I. The planet discs are significantly brighter and no floaters are evident whatsoever in the 1.42mm exit pupil offered up. This is a very pleasing eyepiece for planets at this magnification and I have spent about as much time with this on planets as the 4.7mm.

On Jupiter the same false colour is evident in this eyepiece and it appears again at 60% as a browning on the trailing edge of the planet disc. At about 80% out a blue hint appears on the leading edge of the disc and this is evident to the field stop. Given the increase in brightness the false colour is more evident here than at the higher magnification. The eyepiece holds focus well to the final 5% with good detail still evident right on the field stop.

I also used this eyepiece to view some galaxies; of particular note were M81, M82 and M65. The contrast at this magnification provided me with some detail in M81 and M82 that I have never observed prior, seeing dust lanes and spiral structure. The satin black backgrounds really helped to pick out additional detail. It was like looking at a galaxy on the edge of an abyss. In M65, while looking for the current supernova, I was able to discern a number of extremely low magnitude stars - around Mag+13. Given I view from an urban location I am impressed that I was able to see stars of this magnitude with direct vision.

My conclusion is that this is a much more tolerant eyepiece for planets than the 4.7mm but offers less detail for it. It is more comfortable to use than the shorter focal length but still tight on eye relief. I found it offered some latitude for usage on deep sky objects that I had not attempted before with previous eyepieces and found this to be both pleasant and revealing. I am yet to assess the performance on the moon but I expect it will perform very well here. The false colour on planets is quite evident in the final 15% of the field but at this magnification you have to be waiting a while for it to drift that far and in practice you are likely to keep a planet within this field for the majority of your viewing. If you are on a budget and are choosing between this and the 4.7mm I would recommend this one as it has more versatility and it slightly more comfortable to use.

Explore Scientific 8.8mm 82° AFoV

Weight: 257g Eye relief: 14mm

136x 0.60° TFoV 1.86mm Exit pupil

This eyepiece is fatter than the smaller pair and shorter. Side by side it appears the shorter stocky cousin; in the hand it feels a like nice lump of metal, glass and rubber. You know it’s going to be a good one before you even put it in and does it deliver. It has the same rated 14mm eye relief as the shorter focal lengths but I am comfortably able to see the entire field in this eye piece with the rubber eye guard rolled up. I therefore question the specifications provided by Explore Scientific. The eye glass portal is measured at 18mm and recessed about 6mm, approximately twice that of the previous eyepieces.

In use this eyepiece offered up incredible views on every deep sky object I pointed it at. The backgrounds are abyssal black and the clusters are exceptionally well resolved. M13 being a prime target I observed fantastic detail at the centre with a great many stars being individually viewed in the mass. This clarity is visible right across the field with stars being pin sharp right up to the final 5% or closer to the field stop. The central core of M13 was in focus to the final 5%. The eyepiece also performs very well on galaxies offering up good contrast and detail on all targets viewed. The Orion nebula is framed very well at this magnification spreading out across the field whilst also showing clearly the trapezium of stars at its core. The level of detail discerned in the clouds themselves both with and without a UHC filter was exceptional and left me slack jawed for nearly a fully hour when I first put the eyepiece in. I felt like a child opening a present at Christmas, elated. The best I have ever seen to date, a true wow moment. It would be worth buying this eyepiece for this target alone in my opinion. I did not use this eyepiece or any longer than it on the planets and as such can’t report on the false colour observed at higher magnifications in the shorter eyepieces. I expect this eyepiece will also perform well on the moon.

In conclusion this is a near perfect all round eyepiece. It’s very comfortable to use, light, well-built and presents fantastic views on all deep sky objects I observed. In particular this eyepiece offers a magnification in my scope that is perfect for observing globular clusters. This may well be tied as my favourite of the bunch.

Explore Scientific 14mm 82° AFoV

Weight: 261g Eye relief: 15mm

86x 0.96° TFoV 2.96mm Exit pupil

This eyepiece is physically similar next to the 8.8mm. A little shorter and a little fatter is all, very similar in weight and feel. Still incredibly light and giving you that feeling that it shouldn’t be possible for an eyepiece this small to offer up ultra wide field views. The eye glass is more recessed than the previously reviewed eyepieces at around 7mm or slightly more and offering a pleasing portal of 20mm. Due to the depth the eye glass is recessed I could actually not comfortably view the entire field with the eye guard rolled up but with it down and your eye right on the shoulder of the eyeglass portal you are in no danger of brushing the eye glass with your lashes.

Of all the eyepieces this one has seen the lion’s share of my usage spending over four and a half hours in the telescope without a change during one observing session. For me this eyepiece in this scope is a DSO Killer. It offered up fantastic contrast on galaxies with jet back backgrounds continuing at even at this relatively low magnification. I was able to discern objects I have never managed before with a detail that was unexpected and managed to bag many targets in the messier catalogue I had previously been unable to observe. I expected to start to see the signs of coma coming into view in this eyepiece but saw very little evidence of it, some perhaps. Stars remained focus to the final 5% as with the previous eyepieces. My untrained eyes are still leaning their craft and so I found this eyepiece absolutely immersive and error free. I spent literally hours going from target to target, taking in sight after sight and never once feeling anything but a sheer sense of amazement and thanking my good fortune for purchasing this wonderful eyepiece. I would say the step between the 8.8mm and the 14mm is noticeable and I am very much looking forward to seeing what the 11mm offers. It is perhaps serendipitous that because of this ‘gap’ in the eyepieces (although I do have the older 11mm it has remained essentially unused) that the 14mm saw such extended use in that particular observing session and was able to really have its legs well and truly stretched. I feel I tested this eyepiece to exhaustion on deep sky objects including open clusters, globular clusters, nebula and galaxies and it did not once disappoint. For me it has a slight edge on the 8.8mm as an overall deep sky object eyepiece however the 8.8mm does beat it quite strongly on globular clusters and the Orion nebula.

My conclusion is that if you own this scope or one with this focal length and you want a wide field deep sky eye piece, get this one. It’s fantastic, immersive and a true killer eyepiece.

Explore Scientific 18mm 82° AFoV

Weight: 377g Eye relief: 13mm

67x 1.23° TFoV 3.81mm Exit pupil

This is the first 2” eyepiece in the range so far. As 2” eyepieces go it’s tiny. The eyepiece itself is barely wider than the 2” barrel is occupies. The eye relief here is stated as 13mm and that is something of note. It feels tight when you use it, more so than any of the other eyepieces bar the 4.7mm. The eye glass itself is smaller than previous eyepieces at 16.5mm and is recessed about 5mm. The top face of the eyepiece is 44mm across inside the roll up eye guard so you always have the eye guard rolled up to block stray light. The guard sits against your cheek and does its job well without being intrusive or uncomfortable.

In practice this eyepiece is a little odd. The eye relief is tight but comfortable. Of all the eyepieces used so far this one has seen the least usage. It is perhaps due to the change in barrel size I’m not sure but I found the 14mm up to the job for most deep sky objects and didn’t feel the need to really go for this one often which may mean I am doing it a disservice. I pointed it at the double cluster noticed coma is moderately evident. Much less evident than the Meade 24mm UWA I have but I am not reporting that eyepiece’s use here. I feel that this eyepiece would provide the same experience I have had in the 1200mm focal length scope in a 1500mm focal length scope, so a 12” F4.9 reflector and perhaps a 14” F4.5 reflector as well although I would expect more coma in the 14”. In terms of galaxies I found that I needed more magnification in my scope than this eyepiece offered so found it subordinate to the 14mm. In my 6” F5 scope however this eyepiece really comes into its own as an exceptional wide field eyepiece. I feel in my scopes this eyepiece will see limited usage but if and when I upgrade to reflectors with larger apertures and longer focal lengths it will begin to show it’s real form. I feel in my 10” reflector it sits slightly outside of a sweet spot between extreme wide field views and tighter individual galaxy viewing.

In conclusion I find this eyepiece a little tight on eye relief but comfortable nonetheless. I have found myself not using it much and feel I need to spend more time with this eyepiece in the telescope to properly ascertain its true value and find its real place in my collection. Calculations indicate this would perform as well as the 14mm in slightly longer focal length telescopes and will likely reveal itself as a hidden gem when I upgrade to a 14” later in the year.

Overall Conclusion

I am nothing but impressed with this range of eyepieces to date. My poor skill and lack of experience in testing eyepieces is obviously evident in this report but I hope I have gone some way to shedding some light on these exceptional eyepieces and their true visual performance.

If you got this far, thanks for reading my first ever review. I hope it wasn't too boring!

And for all the fans here is the money shot with the ubiquitous can of baked beans:

post-19910-0-19610300-1365714194_thumb.j

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thanks for the report on these eyepieces ,which seem to be in vogue now. the 14mm sounds like a good bit of glass then.

were they bought from the u.s ? be interesting to know what the prices come in at with taxes ect .

they do look quite slim for 82* e/p's dont they .

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A very good overview for people who might be looking to get a few of these.

andrew

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Many thanks for the detailed write up. I've been looking at these eyepieces and you make them a very tempting option.

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I forgot to mention in my last post. Perhaps some of the 'colour' you comment on jupiter could be in part from the planet being now past it's best and in more unstable atmosphere?

andrew

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I had considered that too but it was a repeatable exercise evident in more than one eyepiece with changes in seeing so I put it down to the glass. I may have overstated it but wanted to be as honest and open as possible and not just write a 'puff piece'. Personally it doesnt bother me and I didnt even notice it at first. Only when I started looking critically at them to provide some kind of feedback for our community did I start to pick up on these things.

Certainly it doesn't bother me one bit. I'm sure it's obvious that I'm happy with the purchases. Moving from BSTs and Plossls to these is a really good step up in performance. They also perform quite alot better than a couple of the comparable Celestron Luminos range I had recently but returned.

I'd like to have a chance to run them side by side some TeleVue Naglers, which I consider the benchmark for 82 degree. Also would be good to see how they perform against UWANs and Nirvanas. Maybe I'll venture out and actually meet another astronomer one day. I intend to go to SGL next year so at least there I should have an opportunity to get other's feedback and compare to other similar eyepieces :)

Some have commented on the (praised by me) 14mm showing signs of field curvature. I haven't had the opportunity to look for this critically since the comment was made. I also haven't had any opportunity to look at the moon with them so I'll do a much more condensed follow up on this thread at some point.

Thanks for reading it though. I didn't realise it was going to go on so long when I started writing it last night! Turned into a bit of an essay rather than a first light report!

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Great write up! As well as being helpful for prospective buyers of ES 82 eyepieces, I always like to read about 'wow' moments :)

I've read a number of threads about 82 degree eyepieces recently so I'm tempted to try one too.

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Thats a great report Graham - thanks very much for compiling and posting it :smiley:

It's interesting that each eyepiece in the range has it's own characteristics and you have captured those well. Your "test bed" F/4.7 newtonian is quite a tough one for eyepieces so good to see used for a review. Tests of eyepieces with F/10 SCT's and the like are nice but don't always provide much info on the eyepieces as most do pretty well in slow scopes.

When used in fast newtonians, good wide and ultra-wide eyepieces will show coma (scope generated) rather than astigmatism (eyepiece generated) but sometimes it's difficult to tell which you are seeing and sometimes it can be a blend of both !.

I've noticed the recessed eye lens approach that ES use with my 20m / 100. It's slightly annoying as it does reduce the usable eye relief which means I need to roll the eye cup down to see the full FoV. On the plus side I guess it might keep the eye lens a little cleaner.

You are quite right when you comment that it takes ages in this country to get enough time at the scope to be able to write anything meaningful when trying out equipment. It must have felt good to get some photons through these at last :smiley:

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Thanks John :)

Absolutely, I had a very fortunate night last weekend I think it was in which I bagged a lot of targets over a 5 hour session. I did spend the majority of that time with the 14mm which is testament to it's quality I would say. I suspect it's going to take a few months for me to get a full appreciation for them all but my first impressions are very reassuring. Considering what I paid they could be the best purchases I have made to date.

I am very keen to view the moon in them. I love observing the moon because it is a stark contrast to everything else up there. It really offers up a fantastic array of detail and many varied and wonderful natural formations which are billions of years old. My hope is that these eyepieces enhance that feeling of flying over the lunar surface which I already felt from the BST Starguiders with the 60 degree AFOV. I'll look for some specific parts of the lunar surface to test these eyepieces out. You had made some earlier suggestions to me which I have noted and am patiently waiting to observe :)

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One thing to look out for with the Moon is to see whether it changes shape in the outer parts of the field of view. I've found this quite common with ultra wide field eyepieces. It's called pin cushion distortion I think and one effect is that a round object becomes slightly egg shaped as it moves towards the field stop. It seems to be a trade off that eyepiece designers accept in return for a very wide field of view.

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that is certainly on my list of things to look for. It'll obviously only be evident in the 18mm and perhaps the 14mm which should both show the whole disc. in the higher magnficiations I'm going to look for false colour on crater rims, resolution of hard to spot objects (although this is as much a test of the mirrors than it is the eye piece, only really valid using a comparable eyepiece in the same scope) and then tracking them to the field stop to check for focus drop out.

I do have an 18mm BST so I could perhaps do some tests side by side with the 18mm ES82. I'm not sure how valid a comparison that is as you would expect the ES to perform much better but it still may give some level of comparison at least. Do you think that's worthwhile or would provide some value?

It should be more obvious to spot when things go out of focus on the moon than star point and planets as planets are effected much more by seeing and star points could be effected by a number of things at field stop which I am quite unexperienced at telling apart from one another.

It's all good fun though, I just hope it helps people in some way. :)

Edited by Stargazing00

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I think directly comparing eyepieces of similar specifications, if not price, is always worthwhile. Thats often when you notice characteristics that you otherwise may have overlooked. Keep all the other factors the same (ie: same objects, same session, same scope) and sometimes it's surprising what the results are.

What you will find though is that you will know much more about the eyepieces after a few months of using them. It's over time that their little quirks become clearer and you discover how you really feel about them. And all eyepieces have quirks, even the £500+ ones !

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I also have a 5mm BST which is close to the 4.7mm ES. No harm really in running them side by side and seeing the differences I guess.

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Graham, many thanks for providing such a detailed report on the ES82's, it's extremely useful to here how these are performing in a fast scope and gives me some confidence that I will enjoy these in both my F5 (newt and refractor). I'm currently weighing up the options, but will probably stick with 1.25" and get the 6.7mm, 8.8mm and 14mm at first go - though at FL's of 1000mm and 760mm, I won't get quite the same levels of magnification, but hope the Baader x2.25 barlow will be possible with the 8.8mm on very good nights.

Would be very interested in hearing how you did with delivery and import tax on this purchase and which dealer you used.

Thanks again and look forward to you hearing how you get on with lunar viewing in the near future.

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Hi Jake,

I think you'll find those eyepieces will perform very well in your scopes. I use them in a F5 750mm reflector as well and find them all useful. The 4.7mm offers similar views to the 6.7 in the 10" for instance.

I got 4 from the US (telescopes.net) and 2 from Germany (optical-systems) the prices were as stated on the sites.

The import charges in total for the american package which was $450 came in at £45 if I recall. Less than I was expecting. These took about 10 days from being sent from California to clearing customs. I drove to the ParcelForce depot to pick them up because I couldn't wait for delivery!

There were no additional charges at all buying from Germany and delivery was only 10 Euros for the 2 eyepieces. The delivered using UPS to the wrong address. I'd listed bill to home ship to work and they delivered to home. That's probably optical-systems error in fairness to UPS so be aware of that. Thankfully a neighbour took in the parcel for me and it was ready when I got home. This delivery took 3 days once it was dispatched. From order to dispatch was 3 days (the website quoted 2-5 so thats fine).

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I was out last night with the 18mm trying to give it a bit more use. I only had about 30 minutes between some clouds and I had the 6" F5 out as the ground was wet.

I had to work quickly and from memory as clouds were pushing through so I viewed only the following targets: M81, M82, M65, M66, M44, double cluster, M3, M13, M92, M53, M42 & M35

It's actually quite pleasing eyepiece in this scope. It framed the galaxy groups nicely and set them in context. The backgrounds were a little oange washed for my taste but a neodynium can filter this sickly orange glow out quite well in my experience. The globular clusters were visible but not much to look at in this low magnification in a smaller aperture. I decided to look at a couple of the richer clusters. First M53. This look really nice spread out across the centre of the field with some evidence of the nearby NGC open cluster creeping into the edge of the field. I managed to frame almost all of M44 which was nice. I did notice some coma though as you'd probably expect. Well I'm not sure it was 100% coma. The effect was such that when I was looking at the central field a great deal of the field in my periphial vision looked blurred and ever so slightly stretched however when I moved my eye to look directly at those stars they were in focus and fine. I am guessing that this is coma and the human eye can pick up on the subtle elongation much more apparently in the periphial vision than direct vision in the same way we use averted vision to view faint objects like galaxies when direct vision reveals nothing. If this was the case then the coma is apparent in rich star fields in this eyepiece from about 50% out and only in the periphial vision. In direct vision there was no visible distorion of the star shapes whatsoever right to the field stop where the star points appear in focus until they drop off the edge. the same was evident on the double cluster being a denser rich star field. In normal viewing, say on galaxies such as M81 & M82 or the Leo triplet this was not remotely visible. It appears only when looking at dense areas of stars.

In this scope I also tried a number of the other eyepiece and occasionally noticed a faint dark ring in the periphial vision near the field stop. I believe this may have been the secondary mirror obstruction but need a steer on that. I believe the secondary mirror in the Explorer 150p is of a size that allows it to be slightly visible in this way.

For further information, the 18mm in this scope produces 42x magnification, 1.97 degress true field with a 3.6mm exit pupil. the view and the abberations described here are identical to those viewed in my larger 10" F4.7 with a Meade 24mm UWA which produces 50x magnification, 1.64 degrees true field with a 5mm exit pupil.

This leads me to believe that a coma corrector is requred for use in both scopes at low magnifications. this should not be unexpected really.

Edited by Stargazing00

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Really interesting to read that, thanks for making the effort Graham :)

I'm just venturing into BST territory so those comparisons would be interesting. I have the 12mm, first light last night was pleasantly surprising vs my old workhorse 8mm and 30mm NPLs. I was going to put some first light observations up but I can't compete with this!

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Excellent - I have the 6.7mm & 14mm on order and this review has just heightened the anticipation! Can't wait

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Great report Graham, thanks for that :cool: it's interesting to hear that they don't disgrace themselves in much faster scopes than mine :D

If you like the 8.8 and 14, the 11 should not disappoint either... it must be my most used out of the bunch, probably because at about 185x in the C8 it's about as high as the sky will let me go most nights :(

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Hi there Graham.

You are bang on with your assessment of the 4.7 and the 6.7 eps.

In my AD12 F4.9 dob and my AR102 'fractor these two eps shine!

Of course the 4.7 gets less focuser time but when conditions allow

and you slide this puppy in you'll find (IMO) views that take ones

breathe away. You haven't focused on the moon yet?

Well your in for one heck of a treat. I'm not a moon guy but when it's

there ....well...you just have to view it for ALL its worth and these two

EPs dont disappoint.

I think the 18mm will grow on you over time. I had to make an effort

to make sure my investment wasn't going to waste. The 18mm fills

a niche when trying to find that perfect view in the conditions that are

present at that moment.

I'm looking to pick up the 11mm or the 14mm for use in my PST.

The 4.7 and the 6.7 are simply amazing in this scope and Im hoping that

the 14mm will round out what I need to put in its case.

Very good review Graham...you put into words that I couldn't express if

I tried.

Kindest Regards

Bob

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Graham,

Thanks for this review! I note that Explore Scientific now has revised eye relief specifications at http://www.explorescientific.com/eyepieces/82_degree_series1.html as follows:

4.7mm 13.6mm

6.7mm 15.7mm

8.8mm 15.6mm

11mm 15.6mm

14mm 15.6mm

18mm 13mm

I find the 8.8mm and 11mm usable with spectacles (but I am very short sighted) while the 6.7mm is marginal. All have the eye lens sunk into the body and in practice the 4.7mm and 14mm have tight eye relief. With glasses, the view in the 4.7mm is vignetted and really usable only for focusing for a partner. I could not get on with the 14mm and have replaced it with the 16mm 68º which has a slightly smaller true field, but I find it to be a delightful eyepiece.

I have not seen lateral colour in any of the 82º eyepieces and other aberrations also seem to be very well controlled.

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Excellent review Graham. I have the 11mm and it is a great eyepiece (IMO). I bought it as an upgrade from my Revelation plossl set adn was bowled over with the jump in quality, primarily contrast is much improved. Lately I have notice that this is pretty much the only eyepiece I use, consequently I now have the 6.7 and 8.8 on order from the states. To say I am looking forward to the views is an under statement. I also have my eyes on either the 24 or 30 later in the year, at which point i suspect my Revelation plossl's will be redundant.

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I was out last night with the 18mm trying to give it a bit more use. I only had about 30 minutes between some clouds and I had the 6" F5 out as the ground was wet.

I had to work quickly and from memory as clouds were pushing through so I viewed only the following targets: M81, M82, M65, M66, M44, double cluster, M3, M13, M92, M53, M42 & M35

It's actually quite pleasing eyepiece in this scope. It framed the galaxy groups nicely and set them in context. The backgrounds were a little oange washed for my taste but a neodynium can filter this sickly orange glow out quite well in my experience. The globular clusters were visible but not much to look at in this low magnification in a smaller aperture. I decided to look at a couple of the richer clusters. First M53. This look really nice spread out across the centre of the field with some evidence of the nearby NGC open cluster creeping into the edge of the field. I managed to frame almost all of M44 which was nice. I did notice some coma though as you'd probably expect. Well I'm not sure it was 100% coma. The effect was such that when I was looking at the central field a great deal of the field in my periphial vision looked blurred and ever so slightly stretched however when I moved my eye to look directly at those stars they were in focus and fine. I am guessing that this is coma and the human eye can pick up on the subtle elongation much more apparently in the periphial vision than direct vision in the same way we use averted vision to view faint objects like galaxies when direct vision reveals nothing. If this was the case then the coma is apparent in rich star fields in this eyepiece from about 50% out and only in the periphial vision. In direct vision there was no visible distorion of the star shapes whatsoever right to the field stop where the star points appear in focus until they drop off the edge. the same was evident on the double cluster being a denser rich star field. In normal viewing, say on galaxies such as M81 & M82 or the Leo triplet this was not remotely visible. It appears only when looking at dense areas of stars.

In this scope I also tried a number of the other eyepiece and occasionally noticed a faint dark ring in the periphial vision near the field stop. I believe this may have been the secondary mirror obstruction but need a steer on that. I believe the secondary mirror in the Explorer 150p is of a size that allows it to be slightly visible in this way.

For further information, the 18mm in this scope produces 42x magnification, 1.97 degress true field with a 3.6mm exit pupil. the view and the abberations described here are identical to those viewed in my larger 10" F4.7 with a Meade 24mm UWA which produces 50x magnification, 1.64 degrees true field with a 5mm exit pupil.

This leads me to believe that a coma corrector is requred for use in both scopes at low magnifications. this should not be unexpected really.

I'm very much enjoying using this EP in an 8" Dob. For comparison, I achieve x67 magnification, 1.23o TFOV and 3.03mm exit pupil.

I don't find the ER tight, but don't wear glasses and I'm used to my small plossls.

I'm not sure I can add a useful or helpful review, as I'm unable to make any comparisons to similar EPs. However, the difference between my Panaview and the ES is quite staggering.

I thoroughly enjoy using the 32mm. Being able to frame DSOs at low power in a 2" EP is a treat and the softness towards the edges has never bothered me.

Popping in the 2" ES 18mm for me does produce the "Wow" that people often talk about (it did so in my wife too and she's not a great one for the fuzzy blobs!). I may have to wait until autumn for a really pitch black night, but the views so far have been very impressive.

Good contrast, with crisp sharp images to the edge. Galaxies have good structure (if not great detail at the minute) and the large FOV allows them to be framed in context with the background stars. With m81 centred, m82 still lurks off on the edge of the EP and in Leo, the Leo triplet are all still visible. I had a very good night recently in Coma Berenices and Virgo seeing galaxies I'd not seen before and was quite blown away when working my way down Makarian's chain with galaxy after galaxy popping into view. without waxing too lyrical, I can see why people call them the jewels in Berenice's hair! M13 is quite lovely, with a bright white core spreading into individually discernible stars. M51 with its companion have also been a fine sight with definite darker patches, if not spiral arms out towards the edges of the disk.

I'll shut up there, as I'm gibbering and I'm not sure I've added thing to Stargazer's review anyway! :grin:

Cheers

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On 4/12/2013 at 02:26, Stargazer_00 said:

Thanks John :)

Absolutely, I had a very fortunate night last weekend I think it was in which I bagged a lot of targets over a 5 hour session. I did spend the majority of that time with the 14mm which is testament to it's quality I would say. I suspect it's going to take a few months for me to get a full appreciation for them all but my first impressions are very reassuring. Considering what I paid they could be the best purchases I have made to date.

I am very keen to view the moon in them. I love observing the moon because it is a stark contrast to everything else up there. It really offers up a fantastic array of detail and many varied and wonderful natural formations which are billions of years old. My hope is that these eyepieces enhance that feeling of flying over the lunar surface which I already felt from the BST Starguiders with the 60 degree AFOV. I'll look for some specific parts of the lunar surface to test these eyepieces out. You had made some earlier suggestions to me which I have noted and am patiently waiting to observe :)

Wow. I had this 14mm in my shopping cart along with the 4.7mm 82 and the 40mm  68.  I read on CN that the 14 was the worst of the batch and that people were actually returning them, so I pulled that one from the cart. Perhaps I should go back and see what scopes were being used. Mine is 5" APO f/7.5. Hmm, sounds like an outstanding eyepiece here.

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