John

Best split tonight with the Elliott 3 inch refractor was Iota Leonis. Here is what the Webb Society's Bob Argyle said back in April 2017 about this uneven brightness pair: Webb Deep-Sky Society: Double Star of the Month: Iota Leonis (webbdeepsky.com) Pleased to get it with the 3 inch tonight at 171x. Secondary was close in but clearly split and more or less due east of the primary. Quite testing for sub-4 inch aperture scopes I reckon.

Quite nice here. A little hazy perhaps but a good double star night, currently.

Class Brass this evening 🙂

That option did go through my mind as well. A few years back the Skywatcher ED100's were the best value ~4 inch ED's by some distance but recent price rises have got them lost amongst better finished and equipped alternatives such as the Starfield 102 ED. I paid £300 for a mint condition ED100 about 20 years ago - nothing could come near that back then 🙄

Twisting the top section of the eyepiece moves that section up and down but does not move the optics in the eyepiece - it's a kind of adjustable eye cup but does not alter the optical focus of either the eyepiece or the scope. Generally with these designs, those who wear glasses when observing use the top section at a lower position, ie: screwed downwards. Those who do not wear glasses when observing will probably find having the top section in a higher position more effective ie: screwed upwards. I'm not sure where you might get a replacement rubber eye cup from. OVL are the main Skywatcher importer so perhaps they could help ?: Stargazing Telescopes, Binoculars, Spotting Scopes, Microscopes by OVL - Optical Vision Ltd

If I was in the market for a third 4 inch ED refractor, the Starfield 102 ED would be very high up my list and if budget was part of the equation, probably right at the top 🙂 I just can't think of a justification for getting another 4 inch frac though - questions would be asked !!! 😬

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 👍

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.

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 !

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.

"Magnificent Desolation" 🙂

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.

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.

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🙂

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.