Louis D

If you want to replace those stock eyepieces one for one, you'll first need to measure the focuser/diagonal to see if it is 1.25" or 0.965" inner diameter.

You can get a full set of replacement 0.965" eyepieces direct from China on ebay UK here.

You can get a full set of replacement 1.25" eyepieces direct from Amazon UK here.

The optics will be the same for both.  Only the barrel diameter differs.

As others have said, they aren't all that great, but they're cheap and they will put up an image, albeit with very narrow apparent fields of view and very little eye relief.

If you're in the US, you should be able to find equivalents on ebay, Amazon, and even AliExpress.

1 hour ago, Roy Challen said:

When it comes to astro gear, why spend tens of thousands of £££ when we're limited by our rubbish weather? And why buy a giant SUV if it doesn't physically fit on our narrow roads?

But, some of us spend that kind of money on bicycles, hi-fi, fishing, golf etc😄

Yep, different strokes for different folks.

13 hours ago, Don Pensack said:

Mid-range may be determined by your pocket book.

I consider <$100 to be inexpensive (Paradigm, X-Cel LX), $100-$200 as average price (Hyperions, BST 70°, UFF), $200-$350 as medium price (XWA, XW, Morpheus), $350-$500 the low end of high-priced (Delos, Naglers), and $500-$1500 as high priced (Ethos, Nikon HW, Leica Zoom).

My data for the US puts the median price at ~$100, so the pricing pile resembles a pyramid.

Maybe for the US market where we seem to have more disposable income; but for Europeans, based on what I read on here all the time, they consider inexpensive to be $40 or less, step-up around $40 to $100, mid-range $100 to $200, and anything above $200 is considered expensive.  I literally never see discussions about eyepieces over $500 on here.  No one ever starts a thread critically comparing their Noblex 12.5mm to their Apollo 11mm to their Nikon HW 12.5mm.  There are a few UK folks who do own such eyepieces, but they've all migrated to CN to discuss such things.  In fact, if you do try to start such a thread, it turns into a discussion of why anyone would need such an expensive eyepiece, let alone three of roughly the same focal length.  For example, years back, I started a thread asking about a comparison between the 27mm Panoptic, the 30mm ES-82, and the 30mm APM UFF.  Literally crickets for months, so I finally bought the APM myself and did a critical comparison of the three, writing it up on here.

It's largely the same for cars.  Americans regularly drop $50,000 to $80,000 on SUVs and even more on pick-up trucks and their large SUV brethren.  Over and over on here, many folks don't even own a vehicle, and when they do, it's tiny, severely limiting how big of a scope we can recommend even if they had the disposable income to purchase it.  You would think with either not owning a car or owning a tiny one, that they would have tens of thousands of dollars of extra disposable income to spend on their hobbies, but that never seems to be the case on here.

I won't even get into the motorcycles, off road vehicles, and boats that many American indulge themselves in, but seem quite rare for working class Europeans.  Perhaps they spend their money on other toys that don't interest Americans.

Sounds like a plan.  Keep us informed if you do actually pull the trigger on such a scope.

51 minutes ago, vlaiv said:

I've since managed one observing session with this combination - and it works great.

Ergonomics is not that great, especially if using diagonal and eyepiece in regular way and then trying to screw in all adapters in the dark, but once properly setup - gives great reduced images. Very nice stars to the edge and can fit whole M31 in the FOV.

Just buy another diagonal for use with all of your other eyepieces and leave that modified diagonal dedicated to widest field viewing.  Simply swap diagonals as a unit to move upward in power from the widest field unit.

This web page and this web page claim a Samsung Galaxy S20 FE can take panorama photos.  Is the Panorama mode option not showing up with your phone's camera app?

I'd agree that at least for the 9mm Morpheus versus 10mm Delos, there is very little to choose between them image wise.  I have no issues holding the exit pupil while wearing eyeglasses with either.  The fact that the Morpheus has a noticeably wider AFOV is a bonus in its favor.  In the US, there's only an $88 ( £70) difference between the two, so not such a huge difference as in the UK.

3 hours ago, LondonNeil said:

No love for Hyperions?  Look around for used and these aren't hard on the wallet,  particularly given the versatility if used with tuning rings

Well, they're $169 apiece new in the US, so well above what I would consider as mid-range eyepiece pricing.  I consider $100 apiece pushing that title.

Used, they're going for around $90 +/- $10 here in the US.  I suppose if your budget allows, they would qualify as mid-range when purchased used.

There are also the various Redline 70 degree eyepieces out there as well in that same price range new and used.  The 22mm is excellent.  The rest have varying levels of aberration issues.

Face it.  Experimenting and tinkering with various astro bits and pieces can be a lot of fun.

I did a bit sleuthing online and found these two rather informed sounding posts on the subject of plastic and aspherical lenses:

https://www.photo.net/forums/topic/390353-plastic-elements-in-aspherical-lenses/?do=findComment&comment=3991482

https://www.photo.net/forums/topic/390353-plastic-elements-in-aspherical-lenses/?do=findComment&comment=3992009

1 hour ago, Cosmic Geoff said:

(One can anticipate that the chromatic aberration will be worse with the larger ST120.) I use the ST102 for EVAA imaging of galaxies and star clusters and do not feel it is fit for much else.

Based on my visual experience with my KUO 152 f/5.9, I would think nebula would be ideal for these fast scopes.  I certainly can't see any chromatic aberration in the actual nebula.  Of course, there is a bit in the stars in and around them.  However, if you used narrow band filters and refocus for each, I would think they would largely suppress both chromatic and spherical aberrations.  Star colors might not be very natural, but perhaps software could be used to remove them?

Just bolt the new, longer rail to your existing rail using 1/4-20 x 1/2" socket head cap screws.

Since FLO doesn't show the bandpass information for that filter, I'll have to assume it's a fairly broad bandpass filter.  In my experience visually, they don't help all that much viewing anything.  I prefer a UHC or near-UHC filter with much narrower bandpasses.  I don't know if they're available in the UK, but I've been impressed with the Svbony UHC for observing nebula.  They're about $30 here in the US and work nearly as well as my 1990s vintage Lumicon UHC filter.  The latter has somewhat narrower bandpasses, but visually, they look quite similar under my Bortle 6/7 skies.  They don't really work as light pollution filters for general observation because such a thing doesn't really exist anymore in the era of LED lighting.  It was simple to filter line emission light pollution in the past when street lights were mostly sodium or mercury vapor, but LED lighting tends to be broadband, so it is nearly impossible to filter out while leaving something for our eyes to see.

Below is a composite of various bandpass filter images I've taken with my spectrascope as well as a rather generic Zhumell Moon & Sky Glow (M&SG) filter.  The M&SG is going to be nearly identical in performance to a Baader Neodymium filter.  See the second image comparing the two made by a CN contributor with a professional spectrometer.  As such, save your money and get a generic M&SG if you want to try one.  They're under £10 direct from China on ebay UK.  You can also stack it with a cheap light yellow filter to cut some of the violet/blue light to make a poor man's Contrast Booster filter.

3 hours ago, bilbo said:

Avoid wedges with Evo mounts

So, do you then need to add a field derotator to image using one?  I didn't see one in the image above.  Is it done in software?  That is, derotating many short images during stacking?  Does that work well with DSO imaging? Thanks!

Just put the fork mount in equatorial mode with an equatorial wedge, and you should be able to reach zenith just fine.  Of course, you then won't be able to reach objects near Polaris.  Have you tried this and still not been able to reach zenith?  Perhaps more photos would help.

Visually, at a star party pre-pandemic, I thought that the 8" EdgeHD put up images of Jupiter as sharp and detailed as 8" Newtonians with custom figured mirrors.  Images in standard 8" SCTs on the same night looked mushy and mostly featureless in comparison.  It made me a believer that night.  Basically, that corrector is putting all the photons where they belong in the image, even on-axis.

I believe all Celestron SCTs from 5" to 10" use the same visual back size.  The C11 and C14 are larger, IIRC.

36 minutes ago, Don Pensack said:

I'll adopt the use of zooms when they have a constant 80° field from 8-24mm.

Do you care if correction is horrendous or if the zoom is gargantuan and varifocal?

I would say 12" is right at the max for a solid tube Dob.  I've handled both solid and truss tube Dobs at around this size, and the former are definitely more ungainly than the latter to pick up and move.  Storage wise, the truss is more compact vertically.  Setup time wise, the solid tube is much quicker to get setup.

Once you go bigger, I definitely recommend truss over solid tube.  It took two to three of us at a star party to setup a 17.5" solid tube.  It also required a full size van with all the bench seats removed and a custom cradle to hold it steady.  By way of comparison, I could move and setup a 15" Dob all by myself before an auto accident tore up my back.  Now that there are ultralight versions, 12" to 14" Dobs are a fraction of their weight from 20+ years ago.

I don't know about the UK used Dob market, but 12" to 14" custom Dobs come up used quite a bit here in the US for a fraction of their original new price.  Most come with exceptionally well figured mirrors as a bonus.  Just keep your options open.

Just not jaded enough by years of observing experience and not having used lots of expensive glass to notice any difference.  I was that way 25 years ago.  You can never get back to that point, so enjoy it.  Your wallet will thank you.

I'm guessing it's due to the plane flat and highly reflective imaging sensor reflecting light like a mirror back up the tube.  I recall that some vintage macro lenses designed for film have this hot spotting issue when used with digital sensors.  The Tamron 90mm f2.5 Adaptall comes to mind because it has a plane flat rear element reflecting that light back to the sensor as a hot spot.  This wasn't an issue with film because it always had a bit of curvature to it despite the film rails trying to hold it flat.

I suppose you could try tipping your sensor a bit if you have a tilt adjuster in the optical train.  That would send the reflected image off to the side instead of right back at the secondary mirror.

I just remembered I also have serious issues trying to get eyepieces to stay seated level in my Arcturus binoviewer eyepiece holders because the nylon split-ring in the collet is right on the upper taper of most eyepiece undercuts.  As a result, it follows the path of least resistance and pops the eyepiece upward as the ring contracts.  This is not an issue with smooth eyepiece barrels.

Sure, you could argue the collet split-ring should be wider to avoid this issue, but the same issue has happened to me with some diagonals having their thumbscrew set too close to the top.  Again, no problems with smooth barrels in those oddball diagonals.

I'm happy for you that you've never had any issues with eyepiece barrels.  Many of us have, though.  I, for one, once spent an hour trying to work lose a Tele Vue eyepiece jammed in a focuser with a brass compression ring that worked its way out of its channel and jammed into the eyepiece undercut as I removed the eyepiece.  Had it been a smooth barrel, nothing would have been snagged.

The only time I've ever had a need for a "safety" feature was when a diagonal decided to unscrew itself and rotate upside-down, dumping a lightly tightened eyepiece.  Luckily, my eyepiece went into grassy turf and not cement.  Based on that, I'd say the problem lies elsewhere in the mechanical chain, not in the eyepiece holder.

My biggest gripe with my 127 Mak is cool down (warm up) time relative to a Newtonian mirror of the same thermal mass.  To me at least, it seems like that front corrector impacts image quality much more than a cooling (warming) mirror does.  As such, if I just pop out for a quick look at a planet, the Mak will show all sorts of color fringing around it absent in the 6" Newt.  Thus, the Mak is not a good choice for quick grab and go observing.  I've found a similar problem with my 90mm triplet APO.  For the first 30 minutes of cool down (warm up), it appears to have pinched optics.  This does not happen in my 72ED.

If you give the Mak time to acclimate, it will provide excellent high power images.  The Synta version (Celestron, Orion USA, etc.) also holds collimation exceptionally well.  Being compact and holding collimation well, it also makes for a good travel scope to take on vacation or camping.

BTW, I mention warm up because during the summer, my equipment has to warm up from my A/C cooled house temp to the often quite hot outdoor temp.