John

It looks more like a 5 inch than a 4. 

The brass focuser reminds me of Sir Patrick Moore's Cooke 5 inch:

I think I'd do the same - move the 130 on to a new owner. 

The 8" dob and 4" mak make complimentary and contrasting companions I think.

Your photo illustrates nicely how an 8" dob is compact for it's performance advantage over the 130 eq mounted newtonian.

Great report !

You make interesting points regarding premium eyepieces and filters.

When I've had the opportunity to observe with 20 inch dobsonians, I can remember the amazing views but not which eyepiece or filter was being used at the time 🙂

Star parties are great for getting a taste, even if brief, of a range of other equipment 👍

3 minutes ago, Roy Challen said:

I've never used Hyperions, but the fine tuning rings sound like a great idea. Why don't other manufacturers use them? Patents?

I think the main drawback is that you are opening the eyepiece up to install the FT ring. It goes between the upper body optical set and the lower set. Except for the 24mm which, as Don says, does not have a lower optical set.

I guess it's a fiddly thing to do in the dark and there is always the possibility of dust getting onto the internal lenses of the eyepiece.

5 minutes ago, JeremyS said:

That was a favourite haunt of mine from the 70s until they closed

Mine as well.

Every time I had business in London, somehow my journey home was via Farringdon Road 🙄

For those who remember, I came across this movie on Youtube, Steve Collingwood's channel 🙂

I got suckered out by seeing a clear sky with lots of stars showing. Scope went out. 20 minutes later, clouds rolled back over again. I had just enough time at the eyepiece to see that the seeing was really unsteady, which is a little consolation at least. 

I've now got my 11x70 binoculars on standby in case there is a sudden clearance again 🙄

One thing I have noticed, over and over again, is that a good refractor is capable of delivering to it's full performance potential much more often than larger aperture newtonians that I've owned.

50x per inch of aperture is an often cited top end "limit" for scopes. My newts have only very occasionally been useful to use at 50x per inch, most often half of that is where they have topped out, most nights.

Contrast that with my refractors where 50x per inch is very often entirely comfortable and quite frequently 75x per inch can be usefully employed.

I put this largely down to the UK seeing conditions but I guess obstructions, diffraction, reflective vs refractive efficiency and system optical accuracy (rather than just the primary) come into play as well.

Doesn't help with your decision making much though !

18 minutes ago, Flame Nebula said:

Ah yes, Buzz was certainly right. 

Did you take that photo John? 

No, I don't image apart from a few basic "mobile phone held to the eyepiece" type stuff. I just about managed to snap the Hadley Rille once, but only just !

The view through the eyepiece was much sharper than my old mobile phone camera could manage.

7 minutes ago, Flame Nebula said:

.....As a matter of interest, what did the moon look like at x795!? Lunar orbit? 

"Magnificent Desolation" 🙂

5 minutes ago, Flame Nebula said:

Based on vlaiv's calculation, and assuming linear, you'd need a max of 350/200*290, to see all the details resolved in your scope. That's about mag 507x, or 42x per inch, certainly possible I suspect. 

Have you ever pushed it out that far, out of curiosity? 

Mark

Sometimes, more for fun than anything, I used the 2mm setting on the Nagler 2-4mm zoom with the 12 inch dob which gave 795x magnification. I used to observe the moon seeing what it might have been like to be an Apollo astronaut approaching the lunar surface 😁

For more serious observing I used to stay in the 200x - 350x range though, barring the occasional foray a bit higher when searching for faint point source targets such as planetary moons.

I've never really been interested in using maths to work out optimum magnifications for this and that - I much prefer to try things out and see what works and what does not 🙂

I used to use 400x plus with my 12 inch OO dob when searching for faint planetary moons eg: Triton at Neptune, Titania and Oberon at Uranus. I've not managed Phobos or Deimos at Mars as yet.

11 minutes ago, Flame Nebula said:

I wonder if baader do a short zoom. Their 8-24mm is very good. I guess I could use the 2x Barlow to get 4mm. But, to get to the 290 mark, I'd need more. 

Baader do a barlow lens that is expressly designed for use with their 8-24mm zoom:

Baader 2.25x Barlow for Zoom Hyperion | First Light Optics

Are you using a 2 inch diagonal Paul ?

A 1.25 inch diagonal uses up around 30mm less focuser travel than a 2 inch. A 1.25 inch prism even less.

Note: Looking back at a lot of photos of Vixen SP102M's including the one that I used to own many years ago, I feel that they were designed to work with .965" eyepieces / accessories and 1.25" stuff but never intended for 2" accessories. 

The only instance I came across in the UK where someone has successfully found a 2" focuser that fitted the scope and was short enough to allow 2 inch accessories to be used was when a Moonlite CF focuser was used with a bespoke Moonlite Vixen flange. Other after market focusers tend to be too long to allow the Vixen SP102M's to reach focus with 2 inch accessories unless the scope tube is shortened which is not a route that I would recommend.

32 minutes ago, JeremyS said:

I’m just waiting for the cuckoo to pop out for a look 👍🏻

Very unreliable cuckoo, that one 🙄

We found the clock in bits in a shoe box. Put it together and it runs and keeps the time reasonably well but I can't get the cuckoo to synchronise with the half hours and hours when he's supposed to pop out. He is always late, sometimes not at all and occasionally we get an appearance and a volley of "cuckoos" for no apparent reason !

The grandchildren think he's fun though 😁

It's not just you @stuy 🙄

Managed to sort this natty "Tam o' shanter" type objective cap from a wooden lid and an old brass drawer knob. Needs a bit of wood stain but it's a nice snug fit into the dew shield. Should keep the dust out and somehow suits the style of the scope🙂

10 minutes ago, Roy Challen said:

What a fabulous instrument! I agree with a plossl and zoom being the only necessary eyepieces, that's all I bother with in my very similar, but not quite as beautiful, achro.

I imagine once you've collimated it, Izar will be stunning. My scope shows it extremely well at x208.

Thanks !

I've got the collimation spot on now. With the objective cell tight to the counter cell (travel / deliver mode I think) the cheshire eyepiece showed two reflections side by side. Using the push pull screws to separate the cells by a couple of mm then to apply the necessary tilt I have fully overlapping and centred cheshire reflections and very good collimation. Star tests show textbook concentric diffraction rings either side of focus. At F/16 I doubt that's going to need much future attention !

Double stars are going to be the forte of this scope but I'm also looking forward to solar, lunar and planetary observation with it as well 🙂

Incidentally, the eyepiece in some of the pics is the Svbony 7-21mm zoom which arrived today. It's nicely put together and zooms smoothly. The focal length range suits this scope very well giving 57x - 171x and the eyepiece weighs less than half as much as the Baader 8-24 zoom, a factor which also suits such a long tube quite well 🙂

With the 30mm Vixen NPL to give a 40x / 1.25 degree true field, this eyepiece pair will be all I need for this scope I think.

For anyone interested in Ernest (Ernie) Elliott and Gerry Morris at BC&F / Telescope House, there is some more information here:

Ernest J Elliot - Broadhurst Clarkson and Fuller Ltd (bcftelescopes.co.uk)

Just now, Zermelo said:

Quite a beauty, John.

Is the body lacquered, or are you going to be polishing it now and again?

I believe it is lacquered. I'm going to take a "light touch" with regards to polishing. I'm happy for the finish to age gracefully, within reason 😁

22 minutes ago, JeremyS said:

Looks amazing John. And the wooden tripod is just the part. Was that supplied with it?
First light after 30 years, though? Where’s it been in the meantime?

Thanks Jeremy.

The scope has been stored in it's original wrapping by Richard Day since he acquired it apparently. It certainly does not show any signs of having been used. It may well have been displayed at some point though. I have added the 1.25 inch eyepiece holder to the bare focuser tube and the objective cell was tightened down onto the counter cell for transit so I have needed to sort the collimation out, which is achieved through 3 sets of tiny "push-pull" screws. 

The tripod is one that I've had for sometime but not used much lately. I may change the spreader arrangement to a brass chain which would be more in keeping with the scope I think. There are a few further small works such as that to do but that's part of the fun of such a project 🙂

9 minutes ago, Mr Spock said:

Ah, but when seeing is excellent... With the C9.25 I split 0.7", and 0.5" with the 12".

I always like a challenge. At the moment I'm doing a chart for the bottom of UMa surrounding ν and ξ. I note several close doubles, including TDS 8009 at 10.7, 10.7, 0.4". It's worth a try.

Thats great Michael 🙂

I've not had such good seeing here, even when I had larger aperture scopes. 

First solar white light for this 75mm F/16 traditional brass refractor. This instrument was one of a batch of 20 units made by Ernie Elliott at Telescope House just prior to his retirement in 1992. Almost certainly Gerry Morris, who worked with Ernie for a few years, was also involved in creating these telescopes. The objective is by Carton, Japan. I have been gently fettling the instrument since I acquired it a few weeks ago from Richard Day of Skylight Telescopes. Although "only" 30 or so years old this telescope uses a design and manufacture approach that has been used since the 18th century.

Nighttime use has been limited to some star testing but the results have been very encouraging as you might expect from a Carton objective lens. The view of Izar a few nights ago was simply lovely at 150x and held up well even at 200x. Today, despite plenty of scudding clouds, the solar disk and various sunspot activity regions were contrasty and sharply defined up to 171x. Solar filtration was provided by a 1.25 inch Lunt Herschel Wedge. 

Although I intend to use a dovetail bar and the Giro Ercole mount for more serious observing, the traditional pillar arrangement I used today proved surpisingly stable and it certainly looks the part !

I feel privileged to be the first observer to look through this telescope since it's manufacture 🙂

Sub-arc second splits are rarely easy under UK skies, regardless of the scope used, at least that's what I've found 🙄