Louis D

The 14mm Morpheus has very slight field curvature and astigmatism in the outer 15% of the field, so pretty easy to ignore.

The 14mm Pentax XL (XW predecessor) is sharp to the edge once refocused, but has noticeable field curvature.  However, I didn't notice it until I got presbyopia and had to start wearing bifocals.  So, as far as field curvature goes, it depends on your eyes' focus accommodation ability.  Young eyes will probably be fine with the Pentax XW, but not so much with older eyes.  I replaced my Pentax XL with the Morpheus.  Also, 78 degrees vs 65 degrees is an enormous difference.  However, I still think the Pentax XL is very slightly sharper overall.  Contrast and stray light control is about the same.

I've never looked through a 14mm Delos, but the 10mm Delos I do own is spectacularly sharp and flat of field.  The 14mm Delos focus a fair bit below its shoulder, so be aware of this if you have limited focuser in-travel.

I would probably recommend the Morpheus of the three.

Here's my images through eyepieces at around 14mm for reference:

2 hours ago, gilesco said:

Roughly 67.3% of the Pump price in the UK is Tax.

Whereas, in the US, it's roughly 50% (changes from state to state).

I'm paying $0.76/gallon in state and federal gas taxes here in Texas.  That does indeed work out to 48% tax at $1.59/gallon for gas.  Hidden taxes. 🙄

12 minutes ago, IB20 said:

I have purchased the 10mm BCO from Rother Valley. Thanks for all the excellently sound advice as usual!

 

Hopefully you'll have clear skies, so you can report back here on its performance.  I wonder how it would stack up against my 10mm Delos.

You could just get a RDF/finder shoe set for cheap off ebay and replace the ES/Bresser shoe with a Synta/Vixen shoe at the same time.  Synta/Vixen finder accessories are more plentiful and cheaper.

4 hours ago, DaveL59 said:

Anyone recall the great fuel blockade here?

Aside from the 1973 OPEC created oil crisis?  No, none here in the states for the last 47 years.  I had to look up what happened repeatedly in the UK vis-a-vis oil shortages.  The last time truckers blockaded shipments here was indeed during 1973/1974 over the high oil prices and 55 MPH speed limit that hit their bottom lines hard.

Every time there's a hurricane coming out of the Gulf, local gas prices and hotel prices spike to about six times their normal prices.  However, it's pretty easy to report them to their respective state's attorney general for prosecution for violating scalping laws during a state of emergency.  All you have to do is take a picture of the charges with your phone and send it to the AG's office with the location details.  Texas in particular comes down hard and swiftly on offenders.

Some guys in Kentucky were arrested back in April for buying up all the hand sanitizer in Kentucky in early March.  They had somewhere around 20,000 bottles of it bought from dollar stores and other places.  They were trying to sell them for $10 or more a bottle on Amazon, ebay, Facebook marketplace, etc.  People were buying them during the panic even at that price.  What got them arrested was that those bottles were deemed essential items during a declared emergency.

My point is, if you can convince the authorities that astronomy gear is an essential item during this emergency, you could then get them arrested for price gouging.😉

Just now, Fozzie said:

I managed to get hold of a second hand vixen LV 7mm, right in the middle of your sweet spot.. narrow at 50deg.. but a bargain second hand value.. and 20mm eye relief makes it easy to use..  I love mine..

One of the rarest since that focal length was dropped for the NLV and SLV lines.  Double check that it doesn't have a 45 degree field of view.  9mm was the lowest focal length with a 50 degree view to the best of my recollection.

1 hour ago, Zermelo said:

Recent purchase of an 18mm Starguider has taken the last spot in my case, so my options now appear to be:

(a) you have no room left. Stop buying stuff.
(b) you have no room left. The next piece you buy will have to displace whatever you use least.
(c) you have no room left. Buy another case, so that you have somewhere to put that next purchase.

Answer: (c) for me at least.  I have 8 eyepiece cases at last count: A-team, B-team, binoviewer setup, Z-team, big oddball eyepieces, camping case, HD-60 case, Paradigm (Starguider) case.

The pistol grip style tripod heads get recommended a lot for binocular usage on either monopods or tripods:

51 minutes ago, Saganite said:

A shoulder injury 12 months ago which is stubbornly refusing to heal completely  (  68 year old components )

I injured my 52 year old shoulder a couple of years ago in a work fall, and it is still not 100%, so you're not alone.  Give it another year or two, it does get a bit better each year.

My 34 year old back was injured in an auto accident 20 years ago, and it never recovered to 100%.  I had to quit using my 15" Dob as a result of that one.

As Bill Clinton said in 1992, "I feel your pain".

2 hours ago, IB20 said:

I know very little about binoviewer set-ups, I'll admit. Maybe a silly question but are they used with reflectors? 

With a Barlow/GPC/OCS/OCA, you can reach focus even in a Newtonian with a binoviewer.  I'd start with an entry level binoviewer and see if the GPC(s) it ships with work for your setup.  The ones that came with my Arcturus unit were terrible, so I found a vintage Meade 140 APO 2x Barlow based on online recommendations.  The nose piece with the optics is threaded such that it can be screwed onto the end of the binoviewer nose piece just like a filter.  It yields 3x in this usage.  Thus, 15mm to 26mm eyepieces work well for planetary work.  I also tried a recently acquired Parks Gold Series 2x Barlow (same as Celestron Ultima and Orion Shorty-Plus), and it worked just as well by inserting the binoviewer directly into it.

23 minutes ago, johninderby said:

The new Bresser 6” dob is worth a look. Over budget yes but better build quality and  a better  equipped scope with proper bearings, decent focuser etc. Worth the difference if they can stretch the budget though.

https://www.harrisontelescopes.co.uk/acatalog/bresser6-planet-dobsonian.html?gclid=Cj0KCQjw59n8BRD2ARIsAAmgPmJn4sdeN4qVrhK6Hxm8DxN7ukbxHXxoPDzAvGYQ1K21tt4WGRsPDs0aArnCEALw_wcB

That, and it's in stock.  I'd jump on it ASAP if you want it for Christmas!  Most dealers don't realistically expect new stock until February 2021.

I found I was getting the most detail on the planets this year using my binoviewers with a pair of microscope eyepieces and a Meade 140 Barlow nose piece.  The planets were so bright that I couldn't really see good details without having to filter them down.  This was completely unnecessary with two eyes viewing at once.  That, and my brain was able to pick out finer details using two eyes, especially if I bumped my scope and allowed my brain's motion detection circuitry to kick in while it settled.

You might also want to check collimation on that Newtonian with a cheshire.  This is assuming it has the ability to be collimated.

I'd start with some Revelation/GSO Plossls or similar.  Perhaps 32mm and 12mm to start with.  Eye relief will be a bit tight on the 12mm.  If the view still looks terrible, it's the scope or seeing conditions and not the eyepieces.

51 minutes ago, Adam J said:

Hardly a like for like comparison. 

Yes, but you weren't very specific about "a poor fpl53 design before it was outperformed by a fpl51 scope".  Had you said "a poor fpl53 doublet/triplet before it was outperformed by a fpl51 doublet/triplet", then I wouldn't have made my point.

I brought it up because of the expense of FPL-53 has caused a lot of ED/APO designs to use FPL-51 triplets instead of FPL-53 doublets.  So, in that sense, it is a like for like comparison price-wise.

2 hours ago, Adam J said:

Yeah an it would have to be a poor fpl53 design before it was outperformed by a fpl51 scope. In practice I have never seen it happen.

Some of the FPL-51 triplets rival FPL-53 doublets.

Tracking is possible with Dobsonians with either a goto drive or an equatorial platform.  Both options are outside of your budget, and neither is ideal for imaging.

8 hours ago, Voyager 3 said:

How many lenses does the Meade HD uses ? And how many does the APM uses ? The APM , pan , aspheric are quite different in brightness compared to the Meade HD etc . I think it will not cause a difference in night time viewing...

I wouldn't read too much into the absolute brightness of each eyepiece taken in isolation.  The camera was on auto exposure for each eyepiece, and the brightness of the room may have also changed as more or less light streamed in the nearby windows as the day wore on during testing.  What's more relevant is light falloff center to edge within each exposure for each eyepiece.  Notice how the RKE gets dim near the edge?  Notice how the Aspheric fuzzes out near the edge?  These are the relevant sorts of things to look for within each eyepiece's image.

The Meade HD-60s are purported to have 6 elements each.  Four in the upper, positive section, much like a 1-2-1 Konig and two in the lower, negative section, much like a Barlow or Smyth lens.  So, most likely 6 elements in 4 groups.  I can't find any definitive diagrams for you, though.

The 24mm APM UFF has 8 elements in 5 groups as seen below:

The Panoptic uses 6 elements in 4 groups as seen below:

The Aspheric is three elements as seen below:

The Hyperion would yield a significantly wider apparent and true FOV relative to the Meade Plossl.  It might even perform fairly well in your f/10 scope.  Unlike the rest of the Hyperion line, though, it does not perform very well in faster scopes below f/8 or so because it is basically an Erfle variation.  I would get a 24mm APM Ultra Flat Field or one of the other rebrandings (Altair, Meade, Celestron, Orion) out there instead.  It is well corrected even in faster scopes should you ever decide to buy one.

Zooms are very narrow at the long end of their range.  Most affordable zooms tend to have a 35 to 45 degree apparent FOV, so actually less than an equivalent Plossl at that focal length.  They do get decently wide (50 to 70 degrees) at the short end of their range.

The Vixen SLVs are very sharp, well corrected, consistent long eye relief, and have excellent stray light control.  They tend to perform more like premium wide field eyepieces, minus the wide field.  I would only recommend that at 12mm and below because there are better options at longer focal lengths.

Eyepiece tip-tilt is still a concern with the OVL style collets because they're not that deep.  I have the Arcturus version, and eyepieces without undercuts work much better than those with them.  I have to jam eyepieces with undercuts into the holders while tightening them to prevent them from tilting.  At first, I thought my binoviewers were out of collimation until I realized I could rotate the diopter adjuster and bring them back into closer collimation.  I then noticed that the eyepieces weren't seated all the way into their holders.

4 hours ago, MercianDabbler said:

I must admit that I have not yet understood what apparent FOV is all about... and therefore (I guess) what the value proposition of wide angle eyepieces is - clearly I need to do some more reading on that point before committing to spend money.

Wide field eyepieces tend to be addictive.  You may find yourself wanting to go wider and wider until your wallet is empty.

2 hours ago, MercianDabbler said:

Hmm... I've been reading up on apparent FoV. I now understand how it is calculated/measured and what it means... but I don't think that's really what I want to know.

Think of looking through a paper towel tube versus a toilet paper tube versus a one inch long section of the latter.  The field magnification remains the same, but the field of view increases at each step.

2 hours ago, MercianDabbler said:

I'm somewhat puzzled by the idea that both the 6.4mm and 26mm Meades have the same apparent FoV because they are so different to look through... but me being puzzled by astro kit specs is not really news.

You're confused by the two usages of field of view (FOV).  One is true FOV (TFOV) and the other is apparent FOV (AFOV).  TFOV is how much of the actual sky is visible and AFOV is how big of an angle does it subtend across your eye's field of vision as I was alluding to above with the various tubes.

As an extreme example, the original ten or so 9mm ES120 eyepieces came without field stops and had a TFOV just about the same as a 32mm Plossl.  This is because both had about a 27mm field stop (or effective field stop) which is what determines how much of the telescope's image circle (camera speak) is magnified by the eyepiece.  The AFOV though went from 140 degrees (ES-120) down to about 50 degrees (Plossl).  Magnification also more than tripled.  Thus, the experiential difference between the two is enormous.

5 hours ago, Don Pensack said:

THE 24MM APM IS 65° (CLAIMED, 63° MEASURED).

True, but due to distortion, it has a 66° effective AFOV.  At 27.5mm, it has just about the largest possible effective field stop in a 1.25" eyepiece that doesn't require massive in-focus.  The edge does suffer a bit for it, though.

I prefer the 22mm AT AF70 in all ways over the 24mm APM UFF if a 2" focuser is available.  It's cheaper, wider (70° AFOV, 74° eAFOV), better at the edge, and has a slightly larger effective field stop of 28.4mm.  Eye relief and flatness of field is about the same for both.

Except that you're going to want collets (OVL) to keep the eyepieces centered and better aligned than is possible with a single thumb screw (WO).

My neighbor has lights shining up into his trees and bushes at night, as if it serves any useful purpose.  I guess they think it looks neat.  Sort of like putting LED lights under your car.

Here are my thoughts on them:

• Rigel QuikFinder can be difficult to find the circles and has slight parallax issues.  Small and light.  Battery will last 20+ years with no corrosion.
• Telrad is huge but I never have trouble locating the thicker circles, plus they go out to 4 degrees, not just 2 degrees as with the QF.  AA batteries can and will corrode inside, ruining the illuminator, unless changed regularly.
• RDF is cheapest and gets the job done if all you want to do is put the scope on a target.  Haven't used one long enough to declare anything about their battery life.
• Green laser sight is my preference with my injured neck.  Quickest way to put a scope on a target that I've found (1 to 2 seconds).  Americans have embraced them while Brits have eschewed them.  Just look and listen for aircraft before lighting it up, and you'll be fine.