John

Superb lunar views at the moment 😁 Lovely fine detail such as the Rima Hadley cutting across the plain beneath Mons Hadley. The area of the landing site of Apollo 15 clearly on view. I'm working on the basis that the Svbony zoom at 3mm is really giving around 3.5mm so that's 257x in the ED120 and sharp, sharp, sharp 🙂

Only just managed to get the ED120 outside now after a busy evening. Hope it stays clear for a while longer 🙂 The moon looks pretty splendid and it's pretty much right overhead so the seeing is good and steady.

As purely a visual observer I would go for a doublet I think. There are quite a few very positive reviews out there of the 125mm Stellamira and the same scope under different branding. The weight of the Stellamira makes it appealing to me as well.

Tonight looks quite good here, after 9:00 pm 🤞

Some double stars and the moon with my 70mm F/6 ED this evening. Seeing not so great through. Moon was behind the house later so it was worth at least trying for some brighter DSO's. Despite the paltry aperture, I did manage to see M 65 and M 66 of the Leo Triplet group. NGC 3628 was not visible though, perhaps unsurprisingly given the small scope. As Meatloaf sang in 1977, "Two out of three, ain't bad" 🙂

The last one that I saw was on a pretty cloudy day as well. I got lucky with a few breaks in the clouds to snap some photos:

The Myriad has a somewhat more chunky eye cup design than the APM 100's.

Was that even with the top section of the eyepiece in the lowest position Alan ?

I'm currently feeling that my 130mm F/9.2 is as large a refractor as I want to deal with. Like you, from time to time I look at 150's but, having tried some in the past, I'd probably go for a different design if I want to get more aperture again.

Impressive looking scope for an impressive price ! I sometimes wonder if these whopping refractors are designed to attract the crowds at astro shows, as much as anything else 🙄

I've not owned or used the 24mm ES 82 but I have owned the 22mm T4 and 20mm T5 Naglers. They were both excellent eyepieces although, personally, I found the 22mm Nagler more comfortable to use (more eye relief and a larger eye lens) and more immersive. I have read of a number of folks moving from a ~20mm / 100 degree eyepiece to the 22mm Nagler and being happy with the switch. I went the other way but I guess the time might come when I reverse that move 🤔 There are other ~20mm ~80ish degree alternatives now as well such as the Stellalyra 20mm / 80: https://www.firstlightoptics.com/stellalyra-eyepieces/stellalyra-20mm-2-80-ler-uwa-eyepiece.html I've not used one of those though.

Thats a good solution to cool down. And I already have the clear plastic box ......... 🤔

Just a quick look at the moon and a few double stars with my 3 inch F/16 refractor this evening. My first look at the moon with this scope - as I hoped, the slow focal ratio resulted in no false colour visible at all around the lunar limb. Craters along the terminator were filled with jet black shadows. Very sharp views at 171x. As I gazed at the lunar surface, I thought of an 11 year old Patrick Moore getting his first glimpses of the moon with his newly acquired 3 inch refractor back in 1934. He must have been mesmerised by the views 🙂

Thats an impressive list Mike and it shows what can be done with perseverance and some skill. I think it's good to list these things, even if we have achieved them ourselves, so that others, perhaps new to the hobby, can be aware what is possible with amateur equipment. I can recall quite a few instances during my first couple of decades of observing when I learned that something amazing could actually be seen by an amateur with a modest telescope by reading about it in a book, magazine or more lately on a forum. What I thought was beyond the grasp of the amateur, was actually within my grasp, if I was prepared to push for it 🙂

I did a little testing and measurement of 1.25 inch diagonals, mirror vs prism, for @wookie1965 / Paul. After that, the cloud cover allowed a look at Iota Leonis with my Tak 100mm, and that was about it !

I've been doing some measuring for you Paul. I'm using my Tak FC100 so the focuser position at focus is not the same as your Vixen but the difference between using the 2 diagonal types should be the same. 1st photo shows the 1.25 mirror diagonal (similar to your current one) with the Svbony 3-8 zoom at 3mm which is the setting that needs the most inwards focus. The eyepiece is at sharp focus on a star in Leo. 2nd photo shows the exactly same as above but using the Celestron 1.25 prism diagonal. You can see the additional in-focus gain that the prism gives which I measured at 15mm. Hope that helps reassure you 🙂

If the seeing is not too good, the pattern of diffraction rings around the airy disk will not be well defined on one side of sharp focus as it is on the other. This test needs to be done at quite high magnification - around 200x for a 4 inch scope is good. This is what a decent 4 inch refractor star test should look like under very good seeing conditions: Under less than good seeing conditions, the image on one side of focus may well look "mushy" rather than showing well defined diffraction rings. You might still get a nice in focus image though. Polaris is a good test star.

Well, I believe that it is 4.8mm at F/6 so I guess F/5 will be somewhere in between - say around 3mm ? There are formulae that can calculate it accurately but I don't recall them offhand.

I'm very sad to hear of this. Professor Morison gave a talk on double star observing at my Astro Society a few years ago which I found very interesting indeed and I've used the notes he handed out as prompts for observing targets since then. I also enjoyed his thoughts on optics and other things he posted on his website. A big loss to astronomy.

My experience is to get a scope out and see how it looks at the eyepiece rather than to rely too much on forecasts and models. Very often I've had a good session against the predictions, which I would have missed out on if I'd not bothered to setup. Of course there are quite a few occasions when the opposite is true but there you go ! 😉 As @Steve Ward posted earlier, if you wait for optimum conditions, your gear could gather a lot of dust and cobwebs in between uses🙄

Divide the focal length of the scope by the focal length of the eyepiece.

The only zooms that I have owned / used that offer a wide field of view and image quality that really does match or exceed excellent fixed focal lengths are the APM 7.7mm - 15.4mm super zoom: APM Telescopes. APM Super Zoom Eyepiece 7.7mm to 15.4mm with 1.25" connector and filter thread (apm-telescopes.net) and the Leica ASPH 8.9mm - 17.8mm zoom used with an adapter: APM Telescopes. Leica Zoom eyepiece Vario 8.9 - 17.8 mm ASPH. - 1.25" (apm-telescopes.net) The Svbony 3-8mm zoom offers great optical performance but may not be regarded as having a wide angle of view at 56 degrees.

Brass 'n sunshine plus an active photosphere. A nice combination 😁

My favourite is probably the 13mm but the very best performer of the ones I have is the 6mm - I have a quandary 🤔 (I opted for the 13mm in the poll) I have the 21, 13, 8, 6 and 4.7 in the series and really like them all, of course 🙂 The "why" for the 13mm is based on it's versatility in my old 12 inch F/5.3 dob where it seemed to be able to deliver so well over a wide range of target types. I've also owned the 17mm and 3.7mm in the past and liked those as well but the focal lengths were not ones I used much. Just the dear old 10mm to go, which is reputedly one of the best Ethos, so I'll have to try one, one day 🙂

Last night I could see the moon and just the brightest constellation stars through a thin but annoying cloud layer, so I didn't bother observing. It was Astro Society night anyway so I got my fill of astro fodder that way. Interesting talk about the Andromeda Galaxy being visually "warped" at it's extremities - something to look out for if I get a really dark, transparent night later this year when M31 is high in the sky.