mikeDnight

Another option, which includes mount and eyepieces, could be... But then of course you could get a good 4" ED tube assembly for around that price!

If photons are packets of energy, then the greater aperture will gather more photons, and as the rods in our eyes are photo receptors, the more photons hitting those rods the greater the chance our rods will fire. Hence larger apertures enable us to see fainter objects.

Im not sureI'm following the reasonings so far, but as far as a 4" is concerned I've found that magnification needs to be tailored to suit the deep sky target as they do differ. Sky background darkens with increased magnification while the target nebula to some extent becomes more obvious. This can be used to advantage providing the magnification threshold isn't over stretched as contrast increases. If it is over stretched the nebula is lost. Of course the visual acuity of different observers is an aspect of the observability equation that is hard if not impossible to calculate.

I believe in you. I bet you feel so much better now! 😀

Wow! I'd have killed for a scope like that thirty years ago. And I must have spent hundreds of hours lusting over photographs of beautiful 4" refractors owned by those lucky astronomers in the old books I bought second-hand when I started out in this hobby. Such refractors still set my heart racing when they catch my eye over 40 years on. They may be small but they can pack a punch way above their weight.

I wouldn't write them off just yet. They are absoloutly exquisite for studying binary stars. Some time ago while testing out my DZ I barlowed my 1.6mm HR. That gave me a rediculous 1000X magnification. The star image was so perfect and the HR so comfortable to use, (the mount was a driven EQ), that I repeatedly kept checking I was using the 1.6mm because I couldn't believe the view could have possibly been so good. Of course it's challenging to centre a star at 1000X, but for me it was well worth the effort. Still using the 1.6mm but removing the barlow gave me 500X, which was a much easier power to use, yet with just as much of a wow factor.

Adding a little extra padding won't harm and helps prevent any sliding around inside the bag during transit. I did that with mine, although I can't remember the name of the bag manufacturer and there's nothing written on mine. May be paulastro will be able to shed light on the name as I believe he uses, or has used the same bag.

Maybe you should invest in a goto mount Jeremy. 😂

But that's not a refractor. What you really need is this.... I'm sure that if you place an order the rest of us on SGL will club together and buy you a handle for it.

I know the following is labouring the point that a good 4" refractor is a very capable instrument, and I can hear some seasoned SGLers mumbling "here he goes again"! but I can't help myself. The first image compares the view of Mars on the same night as seen through an 200mm F6 Newtonian followed by that observed through a 100mm refractor. 100mm refractor and Jupiter: 100mm refractor and the Moon: Here's a lunar sketch using a 10" F6 reflector: 100mm refractor on brighter deep sky and comets: Here are some of the telescopes through which the above sketches were made: 250mm F6 reflector Below the 200mm reflector used in the first Mars sketch: And finally the 100mm refractor both in an observatory and as an easily portable grab and go: Whatever you do, don't let me try and influence you!!!

I'm not sure I'd agree about that John. I have quite vivid memories of how I felt when sweeping the milkyway using a SW150 F5 Star Travel at my local astro centre. It was twenty years ago but its still emblazoned in my mind. Despite the greater aperture of the many larger reflectors and SCT's, not one scope could match the beauty of the wide, rich, piercingly sharp star fields of the ST150, and DSO's seemed to glide effortlessly into the field of view. It was quite a sight to see under a dark sky, and the memory of that night still makes my heart race. 💓

Most definitely! Refractors are renowned for their exquisitely sharp, tight star images, and that makes them virtually unbeatable for viewing wide, rich star fields. Depending on the aperture you're considering, they can be excellent for brighter deep sky and comet seeking. When considering a refractor for such tasks their being achromatic isn't such a big issue, as chromatic abberation isn't nearly as noticeable on such targets as it is on the Moon & planets. I would consider a 4" to 6" F5 to F8 achromat to be a serious visual instrument. For lunar & planetary I'd prefer an Apochromatic or ED doublet refractor, again between 4" to 6", but the costs increase because of the exotic glasses used in manufacture. For many seasoned lunar & planetary enthusiasts a good 4" refractor may well be prefered to a 6" or even an 8" reflector due to their sharp imagery and ability to often be relatively unaffected by poor seeing conditions. The beauty of the ED or apo doublet is that it can often take higher magnification on such things as the Moon, and double stars due to no or virtually no chromatic abberation. They make excellent all round instruments, but as with all telescopes, as well as having wonderful attributes, they have their limitations.

A Vixen Super Polaris or Vixen GP or GPDX would carry it well, providing you have a solid tripod or pier. With an F15 you might find a Hargreaves strut, which extends from behind the lens cell to the end of the counterweight shaft, halts residual vibration.

I found myself making the transition to binoviewing without really noticing. I simply see more and more easily using both eyes. My main instrument is a 100mm refractor, yet never fail to be amazed at the detail it shows me with the binoviewer attached. I cant honestly call myself a sole bino user, as I enjoy hunting fuzzies using mono viewing, and I also use some single very short focal length high power eyepieces when observing double stars. For lunar and planetary though I almost always use my scope with a binoviewer.

I couldn't agree more! The finest all round visual refractor I ever owned wasn't my FS152, it was my FS128. The perfect combination of size, optical quality, and portability. There was a big jump in performance from 102 to 128mm, but surprisingly not so great a jump between 128 to 152mm. The 128 was carried nicely by a GM8 and even a GP with a strong tripod, but the 152 needed at least a G11 mount to do it justice, so not really grab and go. The FS152 was drastically undermounted on the EQ6 below. The FS128 at Huddersfield astro society ready for the transit of Venus, June 8 2004. The mount, the best I've ever owned, was the Lozmandy made Celestron G11 equivalent. (Better than my Lozmandy G11). My FS128 on a Vixen GP and a solid Peter Drew tripod. And finally my FS152 on a tremulous EQ6. Not a good match!

It's true that his prices may tickle the high side at times, but he offers some good stuff that may no longer be in production. I've bought some lovely eyepieces from him that I couldn't find anywhere else. We generally work on two thirds the new value when selling our gear, but the reality is that most of the optical equipment we use doesn't depreciate physically, and so I might be willing to pay above and beyond for a vintage item that I want and be grateful for it.

I doubt a hypothetical 130 DZ would have any meaningful advantage visually over a FS128. You're wise never to let your 128 go Dave, but if ever it would like to come on its holidays I wouldn't charge it for bed & board.

I paid £3,850.00 for my FS128 in 2003. Although expensive, it was worth every penny and gave me some of the most amazing observing experiences I've ever had. At F8.1 though it was quite long, and although visually Apochromatic, it probably wouldn't suit today's imagers; but for a visual observer such as myself it was an absolute joy. Below are my FS128 being enjoyed by Gain Lee at the Astronomy Centre (Todmorden), and the map of Mars compiled from over thirty sketches of the planet during the 2003 apparition.

I believe its because the moon's are not true point sources, and so being extended objects they play a different game. In my experience telescopes that are supposedly incapable of resolving two stellar point sources are quite capable of resolving an extended object. When any of the Galilean's begin to cross the face of Jupiter and while they are still in the shaded limb area, they each display a definite disc, just as they do on leaving the disc. And as the moon's make 1st or 4th contact they display a definite disc in a 4" scope.

I quite like control knobs tight to the mount as they don't get in the way, and are easy to find in the dark. My refractor is quite short so there's little need for long drive cables. However, with longer scopes longer drive cables can be advantageous. The trouble is that the cables on offer from most astro suppliers are not very flexible and stick out pointlessly, which kind of defeats the point. You can cut a not so flexible cable in half, inserting the cables into either end of an aluminium tube to give a long flexi cable that hangs down rather then out at rightangles. (First image). Below are some pic's, a) of my long flexi/rods attached to a GP and which were perfect for observing through a long Newtonian; b) of my rerfactor on a Takahashi Teegul mount, and c) the short controls on my GP when using my refractor. Really its whatever works best for you.

For getting some really nice views of the planet's, including Saturn's rings, a 150mm F8 Skywatcher Newtonian, a 100mm refractor, or a 127mm Skywatcher Maksutov Cassegrain could offer a lifetime of enjoyment.

I use a dimmable red torch to see the paper unless there's plenty of moonlight, but I rarely ever make a completed sketch at the eyepiece. Instead, I make a rough sketch at the telescope then complete a cleaned up version once I'm back in the house. Like most visual observers who sketch, I'm sure you will soon develop a sketching method that you understand, so that you can later use the information to produce a beautiful finished sketch. Some of my eyepiece sketches can look quite chaotic but I understand the scribblings and numbers I use for brightness estimates of various areas. You'll need to use a dark enough pencil to see the pencil lines in low light.

I paid £400 for a secondhand 4" F13 on an altazimuth fork and tripod in 1986, and it was worth every penny to me. Of course things have moved on and refractors with ED optics in shorter tubes are relatively cheap. I'd imagine £250 would be a rough value given the competition. Back in the 80's there were few in the same league as Vixen, at least that were easily available and in a similar price bracket. I think its beautiful!

I think Peter Drew was the sole UK Vixen dealer back in the 80's. Perhaps the sheep have something to do with Peter being based on the Lancashire/Yorkshire border? Mildly disturbing really!!🐏🐑

Steady on now, you're wishing my life away. I'll be 70 years old in 2032.