John

12 minutes ago, Ags said:

On the subject of TS HRs, here's a glowing review from back in the day.

 Do you still have the HRs, @John?

I certainly don't regret my HRs but I did feel the 9mm was a bit behind a Hyperion 17 + fine tuning rings. 

No, I didn't keep them for long - I caught the "ultra wide" bug shortly after then

6 minutes ago, Stu said:

Unfortunately not John.

OK, thanks.

I'm just think that a £380 mount head really ought to be better than a £140 one when compared with the same load on the same tripod. If the AZ-5 managed 2-3 seconds on the 1.75 steel tripod against 1 second for this new mount on a £360 Berlebach Uni then the AZ-5 is not doing too badly

In some ways this is what a smaller sibling of the T-Rex mount might have looked like

1 minute ago, Stu said:

I’ll try it on my Gitzo John, see how it goes on that.

Do you have an AZ-5 to compare it with on the same tripod ?

Or an Ayo Vamo Traveler ?

Looks great

I wonder how it would perform with a lighter weight tripod that you might use for travel. The Uni 28 is pretty hefty !

Was your AZ-5 on the Uni 28 when you compared the damping times ?. Tripods can make a substantial difference to a mounts performance.

1 minute ago, Freddie said:

2/3 is a good starting point and be prepared to go down from there.

Yep - thats the "rule of thumb" that I use as well.

The Explorer 200P is F/5. The one they use in the dobsonian, the Skyliner 200P is F/6. An F/7 or F/8 would be a very long and heavy tube which would push even an EQ6 to it's limits.

This is an 8 inch F/8:

One interesting thing about the XW's is that they use special coatings on the cemented lens surfaces as well as the glass-to air ones to maximise transmission and minimise scatter. I think some others use this technique now. Not sure if the XL's did or not ?

I've not encountered an XL so I've not had the opportunity to compare one with the XW's.

I suppose after finding that the T6 Naglers were a step up in performance from the T1 and T2 Naglers I've thought that the XW's might provide subtle improvements over their predecessor range but I've not had the opportunity to find out for myself as yet.

We are up amongst the top tier with all of these I reckon though. Vixen LVW's probably up there as well. Vixen need a really good 70 degree line again IMHO.

1 hour ago, markse68 said:

strange that isn’t it🤷‍♂️ like they’ve been erased from history. Do you know what year they were released?

https://www.sciencecenter.net/hutech/pentax/ep.htm

The two examples that I was supplied with had packaging issues and arrived well out of collimation. This has been improved upon now and the scopes are arriving with new owners in good order.

The scope had a lot of potential I felt even given the issues that I encountered. I'd like to try another someday

Edit: Oh I see that Kev has already linked to the above.

3 minutes ago, HollyHound said:

Out of interest, I’ve been assuming 3/8” and M10 are not compatible... close but not quite... is this assumption correct ?

Some of the german made mounts (eg: Giros) state that they can accept both threads but I have always assumed that the machining of the thread was specially designed to handle this.

Maybe the Skytee II "tolerances" are loose enough to accept either ?

The Skytee II is M10 as specified though.

For the cost and trouble of the changed visual back and a decent 2 inch diagonal one could almost have bought a pre-owned a 130mm F/5 newt or 120mm F/5 frac and have a proper wide field scope to compliment the 127 (ish ?) mak-cassegrain rather than going to great length to squeeze a few extra arc minutes of view from a scope who's strengths lie elsewhere.

Well that's my take on it anyway

I use the 17.3 and 14 Delos with the 10 thru 3.5mm XW's to make a 1.25 inch set (plus the 24 Panoptic at the lowest power end). The two longest FL Delos reach focus a tiny bit further in then the XW's but close enough. The other Delos, as with the 24 Pan and the Nagler zooms, about 8mm further out.

I don't mind focus tweaking at lower magnifications but I like to minimize it at high powers if possible.

The 22mm T4 Nagler was my first "big" Tele Vue and I really liked it

Thanks Ant

I've got clouds galore here but not, alas, of the noctilucent variety

16 minutes ago, merlin100 said:

Call me cynical, but doesn't the glue grease hide some possible poor engineering practices? I'm thinking of sloppy fitting moving parts, etc. These could be hidden under glue grease... 

I think there might be something in that.

If the Skytee II was made to the same engineering standards that, say, the Rowan AZ100 uses though, it would not cost £260.

And it does work pretty well, with a little tinkering

When I moved from an 8 inch SCT (Celestron) to a fairly ordinary 8 inch dob (GSO made) I was surprised how the much less expensive dob could produce images of the planets and deep sky objects that were as good if not better than the SCT could manage.

My current 12 inch dob (Orion Optics) has a 21% obstruction and high quality mirrors. Good combination I find

I agree with the point made earlier regarding SCT collimation. I've looked though a few other peoples SCT's and found them not in collimation. I have to confess that I didn't feel able to mention it at the time because their owners were enjoying the views. One C8 that I looked through could barely split Epsilon Lyrae.

With a largish central obstruction I think that collimation needs to be accurately maintained and the contrast and sharpness of the image goes down hill sharply even with relatively small amounts of mis-collimation. I recall that Thierry Legault's website illustrates that rather well.

I used to have a 152mm maksutov-newtonian which had a CO of around 18%  and no secondary supports. The images through that were really contrasty and sharp - the closest to an apo refractor that I've seen from a reflecting system.

That's the AZ-5 pillar extension isn't it ?

My Dad used to drive Alfa's. He said you could watch them reverting to Alfa Particles when it rained.

Tele Vue stickers are useful for covering up marks

2 hours ago, Barry-W-Fenner said:

Do you know if Sky Watcher use a similar method to how Meade built there scopes? I ask as my 12" flex is very heavy at the base / Mirror. I have had the scope almost horizontal looking at the moon in its early phase this month and even then it still feels heavy at the rear.

 

No additional weight in the Skywatcher as far as I know.

I've edited that down by two thirds for you Alan :

"It's a fine snob, I have not seen light for most of my time, I have been awful of late, better Hope you can understand I clearly can't."

Makes perfect sense now

2 hours ago, Rob said:

Equally @John I'd love to fit a feather touch on mine. Did they make/supply the adapter?. I know it would be as much, if not more than the scope. But hey I do love me 127l

(Sorry not wishing to hijack the thread.. just curios)

Rob

The scope is a TMB/LZOS 130mm F/9.2 LW triplet. The FT focuser is standard on that model. I now know why FT focusers have the reputation that they do 

I had a couple of the 127L's (one was branded Meade and the other Bresser but they were identical). The collimation needed adjusting when the Meade arrived but the Bresser was in a better state. I did tweak it a bit but I quite enjoy doing that and the objective cell makes it straightforward. If the focuser is out of true it's harder but that was not an issue with the units that I had.

I would use a counterweight with the Skytee II and the 127L. Any type with the 20mm central hole will fit. Not the full weight of the scope, just a few KG to keep the azimuth axis motion smooth.

Definitely replace the DT clamp on the side that you are going to put the scope on. I use the ADM clamps. The top saddle is suitable for short lightweight scopes only IMHO.

You may want to think about a taller tripod at some point unless you are going to be sitting when observing.

This scope is about the same size and length as the 127L, maybe a touch heavier (9.5kg):

This thread is morphing into "show us a bit of your dob"

Interesting to see these different approaches though.

Meade used to stick a great lump of cast metal just behind the primary cell to counterbalance their dobs and newts. The problem with that was it increased the thermal mass around the mirror which slowed down cooling a lot

Antares is a "between the houses" job for me

And of course it's tint is usually "augmented" by the amount of atmosphere we have to view it through from the UK.