Louis D

Right, astigmatism on the line isn't intrusive.  It's there if you defocus stars, but doesn't scream out at you in focus.

There's the 24mm ES-82 as you suggest, the 22mm Nagler T4, 21mm Ethos, 20mm ES-100, 20mm APM XWA HDC, 21mm Meade MWA, 23mm Celestron Luminos, 25mm ES-100 (close).  That's just off the top of my head.  I'm sure I'm missing some contenders.

57 minutes ago, michael.h.f.wilkinson said:

For what its worth, I have used my XW10 in a Meade 2x TeleXtender (telecentric lens like the powermate), and that works very well. However, I since got an XW5 second hand, and it really makes life a lot easier. Switching between the XW10, XW7 and XW5 (and even Delos 6 and 8 mm EPs with parfocaliser rings) is so much easier than having to refocus seriously when inserting a Barlow or telecentric lens. I really use the telecentrics mainly for planetary, lunar and solar imaging

And that's why the Barlow stays in the focuser once it's in there for me.  I don't do this very often, but it can be fun to use lower lower eyepieces at higher power.  Examples would be the 30mm ES-82, 22mm NT4, and 17mm/12mm ES-92s.  Of course, don't try this without using a telecentric magnifier.  I use a TV PBI in a 2" GSO ED 2x Barlow to make a poor man's Powermate.

3 hours ago, Johan03 said:

Now I am searching for a eyepiece with a focal lenght that fit between 24mm Panoptic and 5mm XW. 

Something around 12mm, give or take a few millimeters, would probably be ideal.  It's going to come down to your preferences for apparent field of view, eye relief, weight/size, 2" vs. 1.25", budget, etc.  I really like my 10mm Delos and 12mm ES-92 in this range.  There are so many choices, though.  Perhaps you could start with your budget and barrel size preferences?

I ordered an eyepiece from Germany to the US a few years back, and the outer box was smashed in, but the eyepiece box inside it was fine.  However, that retailer didn't bother to put packing peanuts or anything else around the inner box, so it was free to shift all over.  Ironically, it may have actually helped it because it was free to move to the other side when one side was smashed in.

Clearly, when production was moved to China between the NLV and SLV lines, the optical designs were not updated, but the marketing and eyepiece labeling groups got lazy (I'm being generous here to not call them dishonest).  It's not as bad as Meade calling their MWA line 100 degrees when they're way short of that.  Your very own Winston Churchill coined the term "terminological inexactitude" back in 1906 which sort of applies here.

I've been using a 5.2mm Pentax XL for 20+ years.  It's very comfortable to use with eyeglasses, is absolutely sharp to the edge, and has very good contrast and transmission.  It works very well to resolve globular clusters, for instance.  The image of them is unchanged as they drift across the FOV.  I've had no incentive to replace it.

The 4.5mm HD-60 and 5mm Paradigm (Starguider) are a bit less sharp and contrasty, but good for those on a budget.  It comes down to quality of lens polish and coatings as well as internal stray light control.

2 hours ago, LDW1 said:

The 171 has great performance vs the cost, I have all three of their models as well as Meade and Orion models !

Sounds like its time for a 5-way zoom shootout. 😁  I'm especially interested in usable eye relief characteristics, mechanism smoothness, and sharpness/contrast center to edge across the focal length range.

You've probably already seen this chart on Tele Vue's Dioptrx webpage; but in case you haven't, I've found it to be pretty accurate about when astigmatism becomes intrusive:

That's not to say it's undetectable right on the line between regions.  It's just unobtrusive enough there for most folks that the benefits of shorter eye relief, planetary specific eyepieces outweighs it.

On 12/11/2020 at 12:03, Johan03 said:

Is the TV Nagler 3-6mm zoom compatible with the Dioptrx lens?

I'll believe Don when he says it's, but why would you need a Dioptrx at such small exit pupils?  How much astigmatism are you dealing with in your observing eye?  I have 2.0 diopters, and below a 1mm exit pupil, it isn't much of an issue.  I still prefer long eye relief at shorter focal lengths just for viewing comfort and consistency across my eyepieces, but it's not essential as it is at low powers.

7 minutes ago, Tasman Skies said:

Super detailed and helpful. I was thinking you would just tell me that it was with a telescope and not the eyepiece on it's own, but you have given me the information to do something similar with my own gear, and for that I thank you most sincerely 💯

I'm an engineer who has to regularly write up detailed processes on how to perform complex tasks, so I can't help it.

Your title caught my eye.  I'm trying to picture a Neutronian telescope.  I gather it would be incredibly dense like a neutron star.  The intense gravity could probably bend light waves alone, dispensing with the need for lenses or mirrors.  However, getting close enough to view anything would be fatal as it would crush you in an instant.  It would also tend to crash through the Earth's crust and mantle and lodge itself at the Earth's core.  That alone would make delivery logistics a nightmare.

As others have said, I would probably err toward the refractor at this price point.

If you want a Newtonian, I would steer you toward the AWB OneSky Reflector Telescope since you're in the US.  It's the same as the Sky-Watcher Heritage-130P Flextube in the rest of the world.  It has been universally praised as a good starter scope.

A good solid tube Newtonian option is the Orion StarBlast 4.5 Astro Reflector Telescope.  It's a bit faster, so it's more demanding on eyepieces and collimation.

5 hours ago, Johan03 said:

Might be a problem when observing faint carbon stars and splitting double stars or just when observing the bright moon?

Not much of an issue on the moon because it is an extended object of considerable size and high contrast.  It is an issue with low contrast planetary features for me.  I can't recall it being an issue for double stars since they tend to be fairly high in contrast.  It might be an issue if you're trying to detect a faint companion next to a bright star.

Afocal projection always has the negative aspect of capturing any image artifacts introduced by the eyepiece and the camera's taking lens.  For the 36mm HA, that would include pincushion distortion and chromatic smearing at the edge:

If you can live with these imperfections, it's not a terrible way to quickly capture images.  I captured the following moon image afocally through a 14mm Pentax XL with an Olympus C4000 camera 16 years ago:

The image circle of many telescopes is simply not large enough to cover a full frame 35mm DSLR sensor.  If you were to draw the bounding box for your cropped sensor on the above image, it would probably show a bit of vignetting in the corners.

A focal reducer will simply squeeze the image circle down even smaller, so you would likely see vignetting on your 700D.

You might want to try a Barlow since it diverges the light cone, spreading it out over a larger image circle.

17 hours ago, wuthton said:

Darwin's evolution where with the passing of time life evolves into something better and improved

See the opening of Idiocracy for where humanity is likely headed. 🤣

2 hours ago, globular said:

astrogloves 

 

I fail to see how these keep your fingertips warm in sub-zero F temps unless you keep your hands in a hand warmer waist pouch while observing.  I'm more partial to ice fishing gloves with flip-up mitten covers.

34 minutes ago, johninderby said:

Hmmmmmm..............🤔

This thread made me think of this. 😁

Of course, I'm more partial to the Big Bang Burger Bar at the other end of the universe:

Than I am to Milliways:

1 hour ago, Don Pensack said:

Try AgenaAstro.com in the US.  They ship to the UK and they carry a bigger selection of caps than anyone else I've seen.

Perhaps @FLO could source similar caps for the UK market?  These replacement cap requests come up quite often on SGL.

18 hours ago, Atlas629 said:

A few years ago I learned the fate of the universe, and my exact place in it - hit me pretty hard. Anyone else share similar experiences?

I figure it's so far in the future, that humans probably won't even be around anyway, so no worries here.  I'm more concerned about paying for retirement in a few years. 😉

2 minutes ago, LukeSkywatcher said:

I know. I dont understand it either if the universe is all expanding at the same speed.....how can the Milky Way and Android "collide,merge". I suppose maybe size and gravitational pull play a part.

My understanding is that locally (e.g., within gravity groups), gravity can overcome the general expansion of space-time at this point in the age of the universe.  If it continues to accelerate its expansion, this would no longer be true at some point in the distant future.

28 minutes ago, LukeSkywatcher said:

The Milky Way and Andromeda galaxies are on a collision course in about two million yrs.

21 minutes ago, LukeSkywatcher said:

I thought it was millions

It couldn't be 2 millions years since the Andromeda galaxy is about 2.537 million light years away, so it would have to move faster than the speed of light to get here in 2 million years.

2 hours ago, Johan03 said:

Would a TV Delite 4mm eyepiece Yield to small exit pupil (0,67mm) at 90x magnification?

That is going to depend on how many floaters you have in your observing eye.  I find that exit pupil to be right at the limit for my eyes.  Below that, I have to keep flicking my eye to move the floaters out of the way for a second or so to see something clearly.

There are folks using Vixen HR eyepieces down to 1.6mm in APO refractors, so it really depends on the person and the scope how low you can go on exit pupil.

On 08/11/2020 at 04:19, John said:

If I can find a suitable glass ball I guess I could have a try

On your side of the pond, you could try Zeiss spheres.

My rule of thumb is, if I can move a star around in the field, and it gets noticeably worse in some areas, I'll check the eyepiece for eye lens smudges.  If they exist, I'll clean it the next day, but never in the field.  It's too easy to grind bits of grit across the lens when outdoors.  If I can't notice any difference across the field of view, then I'm usually good with my eyepieces.  I did do a cleaning day last year of all my eyepieces because I had a bit of free time.  I hadn't done it in years.  There was only a thin, even film on most of them that probably had no effect on the image anyway.  This is all in relation to the eye lens.  I don't recall ever cleaning a field lens (bottom lens) on any eyepiece, let alone disassembling them for interior lenses.  Alright, I did take apart a 40 year old orthoscopic eyepiece that was really cruddy that I had bought used for cheap, but that's a different situation.

The Caldwell catalog is another good resource for showpiece objects missed by Messier.