John

Eyepieces are not that high up the list of things that impact what we see but that does not mean that folks on forums don't spend a lot of time discussing them or (in some cases) a lot of money on upgrading them ! From top to bottom, these factors are generally agreed to be the primary influencers of image quality: 1 - Seeing (not transparency, but the level of atmospheric disturbance which distorts the image moment to moment). 2 - Quality of the primary optics. 3 - Central obstruction size. 4 - Alignment of the optics (collimation). 5 - The diagonal being used. 6 - The ability of the focuser to deliver critical fine focus. 7 - The eyepiece. 8 - The skill and fatigue level of the observer and their eyes.

I'm glad you are impressed by your 12 inch dob - once I moved to that aperture, there was no going back but I did need to find the lightest 12 inch that I could to ensure that it got used often, hence my Orion Optics 12 in F/5.3. I had the 8 inch version of the Revelation (my 1st dob in fact) and had a similar issue with the mirror coatings. The mirrors are decent quality (GSO made) but the over-coatings for the 1st generation Revelations were either thin or skimped so a need to re-coat these is not unusual at all. My current OO 12 was re-coated and hi-luxed (by OO) 11 years ago and the coatings are still immaculate. There are other coating options than OO though, as I'm sure you will find out.

I used to use a 10 inch Orion Optics F/4.8 newtonian on a Giro / Ercole type alt-azimuth mount and it worked just fine. The AZ100 is a good step up again in terms of solidity from what I was using back then. I'm pretty sure it would work well.

The only advantage of the 2 inch eyepiece format is that the apparent field of view for a given focal length can be larger because the 2 inch barrel can accommodate a larger diameter field stop than the 1.25 inch barrel. So in medium to shorter focal lengths (ie: less than 18mm focal length) eyepieces are generally 1.25 inch format because they don't need to be larger. Some do have a 2 inch barrel option or hybrid design to give the option of holding them in the larger focuser drawtube but optically they are still 1.25 inch eyepieces. Above around 18mm in focal length, the 2 inch format allows the ultra and hyper-wide fields of view that have become popular with some (like me !).

I had a C90 for a few months last year for a holiday in darkest Wales. It was on an AZ-3 mount. Certainly very light and compact. I did like my Tele Vue Ranger 70mm though. Good optics and very easy to carry in one piece with one hand. The scope moved on to Roger Vine of the "Scopeviews" website who did a review of it. I think he liked it as well http://www.scopeviews.co.uk/TVRanger.htm This was how I had it setup:

Orion Optics are about the only vendor in the UK that I know of that do not include V.A.T on their listed prices. 20% on the end of the shopping cart can come as a bit of a shock ! (although their website does state prices are "excl. VAT" to be fair)

Canon Optron makes the objective lenses for the Vixen and Takahashi fluorite refractors.

I use a clone of the Hyperflex 7.2mm - 21.5mm zoom: https://www.firstlightoptics.com/ovl-eyepieces/hyperflex-72mm-215mm-eyepiece.html It seems to be a good performer for white light solar and nighttime observing. I have used it for HA solar as well and it worked well. The field of view is quite a bit narrower at the 21.5mm end and widens out at 7.2mm but that is commonly the case for zoom eyepieces.

The laser collimator test is good to determine that the optical axis of the focuser is aligned with the objective lens - the laser beam should exit through the centre of the objective lens if the alignment is correct. Once you have done the above, the cheshire eyepiece is a good way to test the tilt of the objective lens: Probably best not to get too hung up on these tests though !

I'm not sure that it is helpful to critique the responses that folks are giving here like this Mike By all means post your own advice in your own style for the original poster but others should be free to post what and how they like I think. All the responses are well intentioned I'm sure

102mm is the old 4 inches. A very popular aperture. I'm sure 100mm - 105mm's will squeeze in as well though

The Ethos 21mm is currently listed new at £810 GBP at First Light Optics. I understand from that other forum that ES stuff has taken a price hike in the US and is now closer to Tele Vue pricing ?

Quite possible to see Neptune with a 150mm scope. It's actually visible (just about) in a 6x30 optical finder if you know where to look. I spotted it a short while back with my 100mm refractor. It needs high magnifications (150x or more) to show that it is a disk - it's apparent diameter is just 2.3 arc seconds so it would fit between the pairs of stars in the famous "double double" Epsilon Lyrae. I've actually glimpsed Neptune's largest moon, Triton with my 130mm refractor last year ! Here is my report from a few nights back: https://stargazerslounge.com/topic/380941-outer-planets-plus-some-deeper-stuff/?tab=comments#comment-4119610

One additional challenge is that the core optics of many / most scopes are good but those of the low cost accessories that are provided with them are somewhat weaker and do not allow the core optics to deliver to their full potential. The problem for the manufacturers / retailers is that including a decent quality diagonal and eyepieces would add a substantial amount to the purchase price of the scope which might well make it look uncompetitive in the market place, to a newcomer to the hobby.

No HEQ5 pictured Alan ? The HEQ5 was an important step between the EQ5 and the EQ6 I think. You do at least mention it in the last para but the HEQ5 was much more than a slightly enhanced EQ5 I think. Inboard motors for one thing. I'm not at all sure that the EQ4, that you picture, was a Synta product. Several references I've seen have it as a Kenko product (the Kenko NES) and made in Japan. It's probably been cloned at some point by a Chinese manufacturer though. The EQ3-2 was also known as the CG-4 and the EQ5 as the CG-5 when branded Celestron, just to make things even more confusing.

Lovely looking scope - congratulations

I grabbed some gaps in the clouds here with my 100m refractor and got 5 Saturnian moons just now. Iapetus was a bit hit and miss due to thin cloud cover and Enceladus was just too close to the main planet and rings to see this evening - lost in the glare of Saturn. Nice to get some glimpses of Iapetus because I'm re-reading 2001: A Space Odyssey again currently and have just at the part where Dave Bowman encounters T.M.A -1's big brother on that moon

When I've seen LZOS scopes tested independantly (eg: by Herr Rohr) they usually do a touch better than the supplied tests. I think the latter are mainly to demonstrate that the objective has passed the quality control levels stipulated by APM.

There is an Ethos 21 in UK Astro Buy & Sell if anyone want's an alternative. It's not mine !

That looks really superb - congratulations If there are not to be any more for a while I'd better post another pic of mine

As long as you are happy with the views then that is all that matters.

Wicked man

What scope (or scopes) will you be using with these eyepieces ?

If the diffraction rings only appear on one side of the star and / or do not appear concentric around the central airy disk then that suggests to me that there is some sort of collimation error in the optics. It could be the diagonal (if in use), the focuser or the objective lens tilt. You should see something like these images inside the focus point, at focus and outside of the focus point:

You can flip the view in Stellarium to match the view through the dobsonian eyepiece or your finderscope. You can flip the horizontal and vertical orientation using ctrl-shift-H and ctrl-shift-V. I use a red dot / illuminated reticule finder and a right-angle corrected image optical finder on my dob which both give the view as our eyes see it, until I look through the eyepiece of the scope, then it flips both vertically and horizontally. It does take a bit of getting used to !