John

I went 8" -> 10" -> 12" with the 12" giving a really noticeable jump in performance over the 8". Noticeable jump in size and weight as well although my 12 inch is an Orion Optics based one which weighs around the same as a Skywatcher or StellaLyra 10".

This pic shows a 6 foot 2 inch person with 6, 8, 10 and 12 inch dobsonians:

Got my ED120 refractor out and I'm just waiting for Jupiter to clear the trees.

Saturn looks OK at 225x but there is some "shimmer" from atmospherics.

I can't answer the question on why C/W bars cost what they do but the Giro Ercole certainly benefits from a counterweight on the other side to the scope, even if the scope is quite a light one.

The Giro-compatible C/W bars with an M10 screw fitting seem to cost from around 25 Euros for a short one:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p10173_TS-Optics-Counterweight-Bar-L-100mm-D-20mm-with-M10-thread-on-both-sides.html

The one I have is 300mm long:

I've owned 3 of the 150mm F/8's. I found a Celestron CG5 (same as EQ5 but on a 2 inch steel tripod) just about OK with it. A Skytee II with upgraded clamps and counterweighting should manage it OK. An HEQ5 is better still.

The 150 F/8's need a tall tripod:

20 minutes ago, Ian McCallum said:

I quite fancy the SW ST150, but what kind of mount and tripod would I need?  Also, what about the SW Evostar 150?

Neither will outperform the 200P dobsonian - I guess you realise that though ?

That's why I use the 21mm Ethos a lot more than the 31mm Nagler in my F/5.3 12 inch dob. More effective exit pupil for my 61 year old eye

15 hours ago, markse68 said:

Check your fujiyamas  though when you get them- my 7mm i only noticed too late has a chipped eye lens- doesn’t seem to affect performance as it’s at the edge but it got through qc and bugs me

Mark

I got a new Baader Genuine Ortho a few years back which had touching lens elements. This only showed itsef as the target object passed through a small central zone of the field of view when it suddenly went blurred and then went back to sharp again. Took me a while to work out what was wrong there

Luckily the eyepiece was a "loaner" from FLO for testing so was quickly exchanged.

Could be a heat plume ?

If you go through sharp focus and defocus on the other side, the position of the "spike" should reverse it's position.

Here is another example of the same thing from another SCT owner:

I guess the choice of "forever" scope depends on your observing interests

If probing into the deep sky to track down faint targets is your primary joy, a 4 inch aperture scope could well leave you "forever" wanting more aperture.

If however solar system targets plus double stars and some "light" deep sky observing are your bag, then a 4 inch might be just the ticket

I can fully understand Ed Ting's #1 choice though - it actually offers you a wide range of observing possibilities

One interesting thing that threads like this throw up to my mind is whether some eyepieces have particular target strengths. So you test eyepieces X and Y on, say, Jupiter one evening and conclude that X is a slightly better performer on that target than Y. On another night, under similar conditions and with the same scope, Saturn is the primary target and the laurels go to eyepiece Y over X, by another small margin. Different targets have slightly different needs to get the best from them ? - I've found something along these lines when comparing eyepieces for this forum and it does lead to some challenges in drawing conclusions, I can tell you !

By the by, on Jupiter, for the past couple of sessions (which happen to have been with my LZOS 130 F/9.2) I've found the Pentax XW 5mm (240x) has been my optimum eyepiece.

Great report on a target that really rewards prolonged scrutiny

"....taking the time to observe...." - such a good idea, for all types of target !

1 minute ago, JeremyS said:

True John. But fortunately they are not overriding, witness the Tak FC 100DL and FOA 60Q 👍🏻

Yes, there are the occasional "outliers" from time to time

The chinese made 102mm F/11 ED doublets came as a bit of a surprise to most I seem to recall.

1 hour ago, Space Hopper said:

Quite the contrary as Olly will tell you.....

I was referring to the 130 F/9.2's being of little interest to imagers. The TEC 140's certainly are.

The needs of imagers drives the refractor market far more than those of visual observers.

I had a chance a few years back to try Baader GO's vs Astro Hutech Orthos vs Fujiyama Orthos and found them practically identical in terms of optical performance. There were a few differences in focal plane position with some focal lengths though, which did cause a little confusion at times. The Fujiyama's were pretty much par focal though their range (I didn't try the 25mm though). The Astro Hutech's were not.

There were rumours when they were launched that the Tak Abbe Orthos might be from the same manufacturer as the Fujiyama's - I'm not sure if that has been confirmed or otherwise now ?

40 minutes ago, jjohnson3803 said:

I'm leaning towards a fast 90mm triplet for my forever scope, but not completely sure yet.  Maybe a 102ED - a little more grasp and definitely cheaper.

I tried a "lifetime / forever / just one scope" 90mm refractor a few years back. It was a 90mm William Optics Megrez ED doublet. Nice scope but I found that 90mm aperture was just not enough to keep me satisfied for long on either planetary viewing or the deeper sky. Now my smallest scope is 100mm for this reason.

I've owned both - 21mm Ethos every time for me. My personal experience is that Ethos eyepieces are a touch better in all regards than the Nagler equivalents (apart from weight and cost). Plus I LOVE hyper wide fields of view

I currently have the ES 92 17mm as well but still prefer the 21mm Ethos.

Darned expensive preferences to have though - I sometimes wish that I saw things differently 

I use a Vixen type dovetail bar bolted to the clamp of my FC100-DL to mount my Tak in my mounts:

20 hours ago, Space Hopper said:

TEC made around 750  140mm units an i bet the fluorite versions are over 100 strong now.

750 ?

Wow !. I think the total number of 130 LZOS F/9.2's made since 2006 is less than 150 units. I guess they are the preserve of the visual observers and of little interest to imagers though.

When I had a 200P dobsonian I had a 102mm F/6.5 ED doublet to compliment it and the pair covered a very wide range of observing interests.

Currently my "fleet" of refractors has grown to 4 scopes from 100m to 130mm in aperture. I still have just the one dobsonian which is a 12 inch.

I do a lot of visual observing with my refractors

I've seen the Pup star with all my scopes down to 100mm now. In the 100mm it was pretty intermittent and needed particularly stable conditions to get a glimpse. I only managed it with that scope a couple of times last winter. With my 12 inch dob now it's usually strightforward.

I usually follow a similar path to Magnus to determine if the conditions are likely to be up to the task.

I find that magnifications of between 180x and 250x work best. Lower or higher than that and getting the split gets tougher !

The Pup star is seen faintly gleaming out of the haze of light created by the much, much brighter Sirius A. The Pup follows Sirius A as it drifts across an undriven field of view. The separation is currently around 11.2 arc seconds but the challenge is that the haze of light surrounding Sirius A extends that far out

I made this sketch of the view with my ED120 refractor in February this year:

In my view it's better to filter but retain the full aperture of the scope. Reducing the aperture reduces resolution so the fine details that a 250mm scope can show will be lost. The aperture in the dust cap of the  250PX is only about 52 mm in diameter I seem to recall so that is a lot of lost performance potential. Not to mention a rather bulky 52mm aperture scope !

Personally I don't use a filter to observe the moon even with my 12 inch dobsonian but I know that some find it preferable to use one. There have been some good suggestions made on which filters might serve well.

34 minutes ago, Stardaze said:

I find the 5mm quite long but those  small nag zooms do look handy John. It’s likely to be my least used EP I guess, but on those special nights, maybe..

I use the 2-4mm Nagler zoom far more than I ever thought I would. With my refractors, it's become my go-to high power eyepiece.

I wonder how many fags you had to smoke to get the full set of the Wills "Romance of the Heavens" cards ?

2 hours ago, Stardaze said:

Maybe I’ll hold out for an HR. Was going to add the XW 3.5 at some point but fancy trying something specific. 

I have the XW 3.5mm and it seems just as good as the 10, 7, and the 5mm. It's a pretty tall eyepiece though and sometimes I prefer the ergonomics of the little Nagler 2-4mm zoom.

Triton's magnitude seems to average out at around 13.4.

Looking at the various scope calculators around on the web, they are fairly consistent that magnitude 13.4 is the limit for a 130mm aperture scope.

I have not seen Triton with my smaller aperture scopes so far, so the optical theory seems sound.

Or can someone do better ?