Celestron X-Cel LX 18mm v. Meade Series 5000 HD-60 LE 18mm

[Relpet]

Recently I bought s/h an Orion Optics UK 12" f4 Dobsonian.  The seller threw in a Meade 5000 HD-60 4.5mm EP.  Last night I managed to get up the hill 200 yards over the road, (OTA on a padded sack truck, mount on a wheelbarrow), 360 degrees no obstructions just terrible light pollution from Crawley/Gatwick.  Tried a few familiar EPs on Jupiter then slid in the Meade.  What a breathtaking moment.  Even with the atmospheric dispersion and light pollution this was my finest view of the planet.  Under better seeing conditions I could have gazed all night.

Saturn is a heck of a long way off at present but even then I could see features in the planet's atmosphere and the Cassini division.  Please come a little closer, Saturn.

Then to Mars.  It was a bit of a race between getting the planet at a decent height before the moon overtook it but, again, under better conditions it would have been an absolute showstopper.  As it was I was quite thrilled to see my clearest view of Mars - ever.

I do most of my observing in SW France but for family reasons am here until September/October.  Most of my quality stuff is in France.  I do have a Speers WALER 17mm which won't focus in the Dob but will in the small Mak I have here.  So I would like to buy the Meade 18mm for the Dob but there is a school of thought that says the Celestron X-Cel LX is much the same quality and construction.  As there is close to £20 difference in retail price I would appreciate, as ever, the opinions of more experienced observers before making a purchase.  Many thanks.

[Ricochet]

I think @Louis D has the HD-60 line and does not rate the 18mm very highly. I think if you're looking for something in that sort of focal length the ES68/82 lines are probably better bets even though they will cost more. 

[johninderby]

I’ve found the 18mm X-Cel LX to be an excellent eyepice and compares well with the shorter focal lengths performance wise. Never tried the Meade 18mm so can’t compare the the Celestron is fine.

[Louis D]

The 4.5mm, 6.5mm, and 9mm Meade HD-60s show pretty much the same views as my 5.2mm Pentax XL, 7mm Pentax XW, and 9mm Morpheus and Vixen LV.  They are sharp center to edge at f/6.  I can't speak for how they would perform at f/4, though it sounds like the 4.5mm is just fine.  The 12mm Meade is sharp in the center but falls off in sharpness a bit toward the edge.  The 18mm is also sharp in the center, but so is a Plossl or Konig.  It really falls off at the edge thanks to astigmatism and possibly field curvature.  The 25mm requires so much in focus, it probably wouldn't work for you.  It is just a little bit better than the 18mm, but not by much.

What to get at that focal length depends on how much eye relief you need and how much field you desire.  I have the 17mm Astro Tech AF70 which is sharper farther out than the Meade and has a 70 degree field.  It's easy to take in the view with eyeglasses.  The 17mm Nagler T4 is sharp to the edge if you focus out the field curvature, but it is difficult to take in more than 70 degrees with eyeglasses.  The 17mm ES-92 is superb center to edge and is easy to take in the entire 92 degrees with eyeglasses.  However, it is massively heavy and long.  The 19mm Russell Konig is very sharp in the center but falls off in sharpness by 50% of the way to the edge.  It is very tight with eyeglasses to take in more than about 55 degrees with it.

Now for eyepieces I don't own and have never personally looked through:

If you don't need long eye relief, an 18mm ES-82 would probably work well at f/4.  You could also try to hunt down the discontinued Meade 18mm UWA in a 1.25" barrel.

There's also the 18mm BST Starguider which might or might not perform better than the Meade HD-60.

Many folks have been raving over the 17.5mm Baader Morpheus.  It's supposed to be much better corrected than the 14mm version which I can attest has field curvature and edge astigmatism.  The 9mm is excellent, though.

A good bet at that focal length would be the 18mm APM Ultra Flat Field.  It's gotten really good reviews and I really like my 30mm APM UFF.

Edit: I just remembered the TV 18.2mm DeLite, 17.3mm Delos, and 17.5mm Nikon SW eyepieces.  All are considered very good as well.

[Ricochet]

2 hours ago, Louis D said:

There's also the 18mm BST Starguider which might or might not perform better than the Meade HD-60.

I don't know if it is better or worse than the hd-60/x-cel lx but at f6 the 18mm Starguider has FC which would only be worse at f4. 

2 hours ago, Louis D said:

A good bet at that focal length would be the 18mm APM Ultra Flat Field.  It's gotten really good reviews and I really like my 30mm APM UFF.

This is probably a great shout, and there's a second hand one sitting on eBay waiting for offers. 

EBay 18mm UF

Edit: in fact it looks like they have two to sell. 

[Relpet]

7 hours ago, Louis D said:

  The 17mm Nagler T4 is sharp to the edge if you focus out the field curvature, but it is difficult to take in more than 70 degrees with eyeglasses. 

A good bet at that focal length would be the 18mm APM Ultra Flat Field.  It's gotten really good reviews and I really like my 30mm APM UFF.

Thanks Louis.  A good read.  I have the Nagler in France, I'm really looking for a few things to get me through the next six weeks or so.  I have a 12mm Starguider here but was looking for something a bit better and the APM job looks just the business.  A later post shows there are a couple on ebay here which I'm looking at now.  I think your post is a real mine of information for other members.  Thanks again.

[Relpet]

5 hours ago, Ricochet said:

This is probably a great shout, and there's a second hand one sitting on eBay waiting for offers. 

EBay 18mm UF

Edit: in fact it looks like they have two to sell. 

Thanks for the tip.  Just been reading reviews in CN.  Nothing less than ecstatic for the most part.  Just need to calm down for a moment.

[Ricochet]

1 hour ago, Relpet said:

Thanks for the tip.  Just been reading reviews in CN.  Nothing less than ecstatic for the most part.  Just need to calm down for a moment.

I just realised they're actually being sold by @pete_gamby if that helps sway your decision.

[Relpet]

I guess they were a bino pair.  Seem to be popular in the States in that way.  Still pondering:  the PayPal account has taken a lot of hits lately.

[Relpet]

On 02/08/2018 at 17:51, Ricochet said:

EBay 18mm UF

 

Thanks for the tip.  Lower offer rejected but have now gone the whole hog.  Really looking forward to seeing how this performs at f4.

[Ricochet]

44 minutes ago, Relpet said:

Thanks for the tip.  Lower offer rejected but have now gone the whole hog.  Really looking forward to seeing how this performs at f4.

Nice. Let us know what you think of it once you've had time to give it a decent test 

 

[TheLookingGlass]

The 18mm Meade HD-60, or the Celestron was loaded with field curvature in my 10" F/4.7. Both will be worse at F/4. The 18mm UF has a LOT of EOFB.

In astronomy, the 17-18mm niche is very hard to get ,(that is fairly sharp for most of the field), at short FL's. 

I tried out a friends 17.5mm Baader Morpheus in a 12" F/5. I compared it to a 17mm Baader Hyperion. 

Believe it or not, I preferred the 17mm Hyperion. Edge sharpness in the 17.5mm Morpheus was not impressive at all. The 17mm AT AF-70 / Celestron Ultima LX is also really good in short FL scopes.

I still own the 17mm Hyperion, which is the best in the entire Hyperion line.

[Louis D]

4 hours ago, TheLookingGlass said:

The 17mm AT AF-70 / Celestron Ultima LX is also really good in short FL scopes.

Funny you say that.  I have the 13mm, 17mm and 22mm AF-70s, and they get better and better in that order.  However, the 17mm has unacceptable amounts of astigmatism and chromatism in the last 20% of the field to my eye even at f/6.  I've consigned it to my B-team outreach eyepiece case.  On the other hand, the 22mm lives with my A-team eyepieces.  It has very little of either aberration in the last 10% of the field.

4 hours ago, TheLookingGlass said:

In astronomy, the 17-18mm niche is very hard to get ,(that is fairly sharp for most of the field), at short FL's. 

Agreed.  I have the 17mm Nagler T4 as well, and while it is well corrected to the edge, it has some field curvature and a very finicky exit pupil that is tiresome to hold.  It is also incredibly hard to hold the entire view with my eyeglasses.

The 17mm ES-92 solves pretty much all of the problems of the other 17s I own except that it is enormous and heavy.  It is pin sharp center to edge with no field curvature or astigmatism.  I've never noticed any EOFB.  The 17mm Nagler T4 has some, and the 12mm Nagler T4 has it all the way to the center.

[TheLookingGlass]

2 hours ago, Louis D said:

Funny you say that.  I have the 13mm, 17mm and 22mm AF-70s, and they get better and better in that order.  However, the 17mm has unacceptable amounts of astigmatism and chromatism in the last 20% of the field to my eye even at f/6.  I've consigned it to my B-team outreach eyepiece case.  On the other hand, the 22mm lives with my A-team eyepieces.  It has very little of either aberration in the last 10% of the field.

Agreed.  I have the 17mm Nagler T4 as well, and while it is well corrected to the edge, it has some field curvature and a very finicky exit pupil that is tiresome to hold.  It is also incredibly hard to hold the entire view with my eyeglasses.

The 17mm ES-92 solves pretty much all of the problems of the other 17s I own except that it is enormous and heavy.  It is pin sharp center to edge with no field curvature or astigmatism.  I've never noticed any EOFB.  The 17mm Nagler T4 has some, and the 12mm Nagler T4 has it all the way to the center.

True, but I found the 17mm was not as bad as you said it was. Plus, the 17mm Nagler is not corrected near the edges at all, until you use it with a coma corrector at F/4.7 to F/5.  Same goes for the 22mm Nagler T4. Exit pupil for me was very easy to hold, but then again, I am one who uses eyepieces with 20mm of eye relief with the eyeguards rolled down with ease.

The 22mm Ultima LX has really nice correction and super easy eye placement. I'd take it over the 22mm Nagler any day of the week at F/4.7 by itself.

I've tried the 17mm ES 92 myself. At first I didn't like it and preferred my Morpheus eyepieces, but after trying it a few more times I got used it. I still prefer the 76 degrees of the Baader Morpheus over those, the Pentax XW's and Delos eyepieces. The Morpheus are my favorite line of eyepieces.

As the old saying goes, YMMV.

Cheers!

[Louis D]

9 hours ago, TheLookingGlass said:

Plus, the 17mm Nagler is not corrected near the edges at all, until you use it with a coma corrector at F/4.7 to F/5.

Assuming you're using it in a Newtonian, yes.  No 82 degree eyepiece corrects for coma or the inherent field curvature of a Newtonian.  Thankfully, most coma correctors not only correct for coma, but also for field curvature.  Even then, there is residual field curvature absent in the 17mm ES-92.

9 hours ago, TheLookingGlass said:

Exit pupil for me was very easy to hold, but then again, I am one who uses eyepieces with 20mm of eye relief with the eyeguards rolled down with ease.

Even with glasses on?  I find the eye relief of the 17mm NT4 too tight with eyeglasses.  So much so that I have to push hard into the eyecup to see to the field stop.  The problem is that the moment the field stop comes into view, if you push in even a fraction of a millimeter more, you'll get blackouts.  Pull back a fraction of a millimeter, and you lose the field stop.  I've found it is too tiring to hold ones head that exactingly for more than a few seconds.  Neither the 17mm ES-92 nor the 17mm AT AF70 have this issue.  The entire AFOV is easy to hold to the field stop without blackouts.

9 hours ago, TheLookingGlass said:

I still prefer the 76 degrees of the Baader Morpheus over those, the Pentax XW's and Delos eyepieces. The Morpheus are my favorite line of eyepieces.

I'll agree they're a nice compromise between 70 degrees and 82 degrees.  I have the 9mm and 14mm versions.  While the 9mm is superb, the 14mm has very noticeable field curvature and astigmatism at the edge.  To enjoy using it, I have to avoid letting objects like planets drift out of the center.  It's fine for observing star clusters where the attention is centered.  I had hoped to replace my venerable 14mm Pentax XL with it because I can no longer accomodate its field curvature, but it trades a wider field for similar field curvature and edge astigmatism that is absent from the Pentax XL.  Having both the 12mm and 17mm ES-92s, I find I don't use any 14mm eyepieces very much anymore.

[TheLookingGlass]

20 hours ago, Louis D said:

Assuming you're using it in a Newtonian, yes.  No 82 degree eyepiece corrects for coma or the inherent field curvature of a Newtonian.  Thankfully, most coma correctors not only correct for coma, but also for field curvature.  Even then, there is residual field curvature absent in the 17mm ES-92.

Even with glasses on?  I find the eye relief of the 17mm NT4 too tight with eyeglasses.  So much so that I have to push hard into the eyecup to see to the field stop.  The problem is that the moment the field stop comes into view, if you push in even a fraction of a millimeter more, you'll get blackouts.  Pull back a fraction of a millimeter, and you lose the field stop.  I've found it is too tiring to hold ones head that exactingly for more than a few seconds.  Neither the 17mm ES-92 nor the 17mm AT AF70 have this issue.  The entire AFOV is easy to hold to the field stop without blackouts.

I'll agree they're a nice compromise between 70 degrees and 82 degrees.  I have the 9mm and 14mm versions.  While the 9mm is superb, the 14mm has very noticeable field curvature and astigmatism at the edge.  To enjoy using it, I have to avoid letting objects like planets drift out of the center.  It's fine for observing star clusters where the attention is centered.  I had hoped to replace my venerable 14mm Pentax XL with it because I can no longer accomodate its field curvature, but it trades a wider field for similar field curvature and edge astigmatism that is absent from the Pentax XL.  Having both the 12mm and 17mm ES-92s, I find I don't use any 14mm eyepieces very much anymore.

True, but some eyepieces correct by having the opposite FC of the Newtonian mirror. Examples are some of the Pentax XW's and some others. The 10mm, 7mm, 5mm and 3.5mm are pretty flat fields in short FL Newts because they have negative FC, while the 14mm and 20mm XW's have positive FC resulting in less than stellar views.

I used to own a 2 inch GSO coma corrector. At the time I also had a 20mm XW. It did not completely eliminate the FC in the 20mm XW, it only cut the FC down to half. So now I own a 22mm Ultima LX and no longer have the coma corrector, and the performance in the 22mm Ultima LX alone is excellent. Only other EP that I really liked alone was the 22mm Vixen LVW. Those EP's are excellent in short FL Newts w/o a coma corrector.

True about the 17mm Nagler T4. I used to also own a 12mm Nag T4, and that one was much worse trying to get into the field stop.....even worse than the 17mm Nag T4.  Get close to see the FS, and blackouts ensue, then when you back off you can't see the FS. It was really annoying at first, but over time, I got used to it. I much prefer the 12.5mm Baader Morpheus over the 12mm Nag T4. So much easier to hold the exit pupil, even with the eyecup rolled down. 

I also owned the 17mm Ultima LX which I modified. I also modified my 22mm Ultima LX. I shaved some of the rubber off the top of the 22mm Ultima LX, so now I can see the field stop easily with glasses. When the top of the rubber was stock, there was no way I could see the field stop on it at all. No problems now though. 

Also true what you said about the 14mm Baader Morpheus and FC, which is why I waited for reviews FIRST before I decided to purchase and I got the 12.5mm instead of the 14mm. The best 14mm EP I ever owned was the 14mm TV Delos and the 14mm Denkmeier. The 12.5mm Morpheus isn't perfect at the edges, but it is passable and not too bad.

I've added a few pics to show what I did to the 17mm and 22mm Ultima LX to show you what I mean. The 22mm Ultima LX is the glasses friendly eyepiece....the 17mm was not as I did not think to shave off the top at the time. I am just waiting for my 28mm ES 68 to arrive soon. 

I also used to own 100 degree EP's. I eventually went back to 68-76 degree EP's with long eye relief as I found the 100 degree EP's a bit much. For me the 68-76 degrees is perfect for long hours of comfort.  An observing friend of mine owns the 12mm and 17mm ES 92's and I really found them a treat to use!  Just a tad too heavy for my liking.

All of my eyepieces have long eye relief and are glasses friendly.  I just leave the adapters on all of my eyepieces so I never have to switch. Everything stays in 2 inch mode, and the 2" filters can go on any of them without having to switch.  The 2" Lumicon O-III in the pic below has a 14mm Baader fine tuning ring attached to it. I only do this because I find it is easier to grip rather than trying to grip the filter alone which is thin and can easily be dropped because of that.

Cheers!

[TheLookingGlass]

[Relpet]

On 05/08/2018 at 17:04, Ricochet said:

Nice. Let us know what you think of it once you've had time to give it a decent test  

 

Tonight was the first chance I had to use the APM 18mm.  It's taken me nearly a week to try every permutation of the low-profile focuser and two extension tubes without real success.  So re-installed the original R&P, covered over the now redundant holes in the tube with black Duck tape, re-collimated, re-aligned and Bingo!  There's a waxing gibbous moon.

This is not a scientific report - I ain't got no edjication, like - but I am truly grateful for the recommendation.  After appreciating the appearance of the entire satellite in the eyepiece I spent a long time looking at detail along the terminator and the limbs.  Super-sharp.  Then thought one way to test the flat field would be to take the moon just off the field of view and then let it float in from one edge to the other.  When it first appeared there was a thin blue line around the limb but this soon disappeared.  It took several minutes for the moon to traverse the entire field of view and during the process craters and mountains stayed sharp, edge to edge.  As the moon started to disappear the last vestige of limb took on a bit of an orange colour but not until the moon was about to fall off the edge.

Light pollution here is so bad I'm not likely to get a true view of star sharpness edge to edge until I can get to a dark site but after tonight I do feel confident.  Among my 1.25" EPs a 27mm Orbinar flat field has always been a favourite.  Now I have another.  Thanks again for the tip for the ebay link and to Louis for the original recommendation.

Peter

[Louis D]

1 hour ago, Relpet said:

Tonight was the first chance I had to use the APM 18mm.  It's taken me nearly a week to try every permutation of the low-profile focuser and two extension tubes without real success.  So re-installed the original R&P, covered over the now redundant holes in the tube with black Duck tape, re-collimated, re-aligned and Bingo!  There's a waxing gibbous moon.

This is not a scientific report - I ain't got no edjication, like - but I am truly grateful for the recommendation.  After appreciating the appearance of the entire satellite in the eyepiece I spent a long time looking at detail along the terminator and the limbs.  Super-sharp.  Then thought one way to test the flat field would be to take the moon just off the field of view and then let it float in from one edge to the other.  When it first appeared there was a thin blue line around the limb but this soon disappeared.  It took several minutes for the moon to traverse the entire field of view and during the process craters and mountains stayed sharp, edge to edge.  As the moon started to disappear the last vestige of limb took on a bit of an orange colour but not until the moon was about to fall off the edge.

Light pollution here is so bad I'm not likely to get a true view of star sharpness edge to edge until I can get to a dark site but after tonight I do feel confident.  Among my 1.25" EPs a 27mm Orbinar flat field has always been a favourite.  Now I have another.  Thanks again for the tip for the ebay link and to Louis for the original recommendation.

Peter

Glad to hear your choice of the 18mm APM UFF worked out so well.  The only downside I've heard about it is edge of field brightening (EOFB) where the sky background gets lighter as you approach the edge.  This should be fairly easy to see in a light polluted sky.  Just point it at a featureless part of the sky and move the scope about and look to see if the background is even in its shade of gray (UK grey?) from center to edge.  Does a faint fuzzy object disappear in a gray muck as it nears the edge is another check for EOFB.

[Ricochet]

8 hours ago, Relpet said:

Thanks again for the tip for the ebay link

No problem, I'm glad I was able to help. Thanks for the report on the performance. 

[bingevader]

EOFB - Edge of Field Brightening.

A new one for me, had to do a little search!

[Louis D]

3 hours ago, bingevader said:

EOFB - Edge of Field Brightening.

A new one for me, had to do a little search!

It's only recently been identified on the various astro fora.  No one knows definitively what causes it in a particular eyepiece's design.  Improper baffling and darkening of an eyepiece's interior can contribute to it, but it's also been seen in extremely well made eyepieces.  Most agree it's more noticeable in light polluted skies.  I've noticed in my 12mm Nagler T4 extending nearly to the center some nights.  It's one of those things you won't notice until you go looking for it, or you get flustrated because you can't see a faint fuzzy except in the center.  The Celestron Luminos line was sunk by early reviews proclaiming their extreme EOFB.

[bingevader]

Ta muchly.

I'm not sure I'll start looking for it!

[Relpet]

On 20/08/2018 at 01:42, Louis D said:

The only downside I've heard about it is edge of field brightening (EOFB) where the sky background gets lighter as you approach the edge.  This should be fairly easy to see in a light polluted sky.  Just point it at a featureless part of the sky and move the scope about and look to see if the background is even in its shade of gray (UK grey?) from center to edge.  Does a faint fuzzy object disappear in a gray muck as it nears the edge is another check for EOFB.

Tuesday night was pretty good seeing here as it happens.  To get a clear view of the sky I have to trundle a wheelbarrow with the Dobsonian mount, EPs etc down my lane, across a highway (A29 in UK terms) then 150 yards up a rutted hillside track to where a chap is rebuilding a windmill.  We are on good terms and he was there on Tuesday so I left the barrow with him before I went back to get the 12" OTA on a padded sack truck to complete the outfit.  Mill owner was blown away by his first sight of Saturn, Jupiter and Mars and lunar craters before he had to leave.  It was then I tried to measure EOFB but it was impossible to discern any real difference.  Blank skies to the south lit by Horsham about 8 miles away;  to the west Guildford, slightly further away but same level of pollution; to the north Dorking, about 8 miles and to the east - worst of all - the Gatwick Airport/Crawley conurbation.  I can make out Ursa Major and Cassiopeia - just - being almost overhead just now but other constellations generally incomplete lacking fainter stars from this vantage point.  If I can get to a darker site (by car!) some time I'll give it a go but I think it's hardly likely to bother me as I'll mainly be concentrating on a central target.  For lunar observation I love it to bits.

[Louis D]

16 hours ago, Relpet said:

Blank skies to the south lit by Horsham about 8 miles away;  to the west Guildford, slightly further away but same level of pollution; to the north Dorking, about 8 miles and to the east - worst of all - the Gatwick Airport/Crawley conurbation.  I can make out Ursa Major and Cassiopeia - just - being almost overhead just now but other constellations generally incomplete lacking fainter stars from this vantage point.

I hope you can make it to a dark sky site sometime.  Your skies sound positively awful.  Enjoy what you can of the skies by boosting your power to dim the skyglow and getting a quality OIII filter.

16 hours ago, Relpet said:

conurbation

I had to look that one up.  Sounded kinda dirty at first. ?