John

Ooops !!! Posted by mistake - forgot that I'm not a mod any more so can't delete it !

I've just looked that one up. One for my 12 inch dob I think. It's currently listed as mag 14.1 which is a touch beyond my Tak 100 and ED120 tonight I think, despite the good conditions. I do like to have a peek at supernovae when possible - thanks for the "heads up" A bank of cloud is headed my way by the look of it so I'd better pop back out and make the best of it !

Got the ED120 refractor out as well now I reckon I've had some glimpses of Deimos which is mag 11.5 or so and around 50 arc seconds SW of Mars just now. Phobos is brighter but much closer to Mars - around 20 arc seconds apart. Mars glow is drowning Phobos out. Need high power to pull these faint specks out of the background sky with Mars in the vicinity - 300x or more. Back in Andromeda and at much lower magnification I've picked up Messier 33 quite nicely. 65x (Delos 14mm) shows uneven brightness across the galaxies face and is enough to pick out the HII star forming region NGC 604 which lies within the outer arms of the galaxy. This small patch of light lies close to a magnitude 11 foreground star. Apparently NGC 604 is over 40x as extensive as the Orion Nebula and over 6,000 times more luminous. It would look an amazing sight if it was within our galaxy !

Quite an unusual combination tonight which is allowing my Takahashi 100 super views of Mars 1 day past it's opposition AND some nice galaxy catches as well. M31 and the Double Cluster are naked eye visible quite easily. Mars sharp and contrasty at 257x and 300x with the Tak. Lots of S hemisphere detail to unravel. Over in Andromeda, Mirach's Ghost (NGC404), a mag 11 galaxy was visible at 65x. That can be tough in smaller apertures because of it's proximity to the mag 2 star. In Cassiopeia the gorgeous triple star Iota is a textbook three way split. Spoiled for choice in these conditions even with"just" 100mm of aperture. Wind is a bit blustery but the slim Tak on the Skytee II is not really bothered by that. Hope these conditions continue for a while longer

I've used my Vixen ED102SS F/6.5 on an AZ-4 mount. Very nice combination and compliments an 8 inch dob perfectly. So I'd recommend something like an ED 102 F/6-7 ish refractor. (the Vixen I have is long out of production).

I have the Lunt 1.25" Herschel Wedge and use it with my 100mm - 120mm refractors. It works very well The Lunt incorporates an ND 3.0 filter within the it's eyepiece holder and I also use a single polarising filter on the end of the eyepiece which gives control of the final brightness of the image. I've not used the others that you mention but I've read good reports on those as well

Yes, Don's annual spreadsheet is a very useful source of information

Well I have a 12 inch dobsonian with excellent optics but I don't use 450x more than very occasionally. Most of my planetary viewing with that scope is done at 150x - 250x and sometimes 300x.

That's what I thought as well.

Well, I think would base it on the largest eyepiece field stop that I would be using. It's not always easy to find that out but it can be tracked down with a bit of googling.

Hi and welcome to the forum. These drawings show the optical arrangements within these different scope designs and I hope explain why the eyepiece position is different. A third design is shown at the bottom - the schmidt-cassegrain. This has an eyepiece position similar to the refractor (at the top): Here is an article which gives more detail about the strengths and weaknesses of these designs (and others): https://skyandtelescope.org/astronomy-equipment/how-to-choose-a-telescope/

I've no idea, sorry. I have used 2 inch diagonals with the Takahashi before - I have an Astro Physics and a couple of Tele Vue Everbrights in that fitting and they work fine with it but I particularly like the Zeiss prism performance with that scope which is why I was asking if the 2 inch Baader zeiss prism is the equal of the T2 version.

I don't think it's going to be a good combination for Jupiter. 450x might work OK under the very best seeing conditions if used on the Moon, double stars and perhaps Mars but Jupiter generally does not respond as well to high powers as those targets. I would think that the 10mm Baader Classic ortho (270x) would be more useful and even then it might be too much magnification to get the best contrast and sharpness from Jupiter.

True. I have a Vixen ED102SS F/6.5 as well as the Tak and that does the very wide thing even better of course. I think I'm talking myself into adding 2 inch fittings to the T2 prism, limiting myself to the 21 Ethos with the Tak at the low power end.

Similar to the 150 mak-newt that I mention above. But quicker to cool down and a little lighter, especially if it is an Orion Optics.

I would rather. I'll send you a PM

Good point Stu. I've sort of lost track of what scopes Martin has owned in the past

I have 3 eyepieces with field stops larger than 35mm: Ethos 21mm = 36.2mm Nagler 31mm = 42mm Aero ED 40mm = 47.5mm I guess the Ethos 21 would work OK with the Baader T2 Zeiss prism plus it has an internal field stop of course which will also be in it's favour. The Aero ED 40 has a field stop below the field lens of the eyepiece so I think will need a full aperture diagonal. I suspect that the Nagler 31 might as well. Of course I could just decide stop at the Ethos 21 mm with the Tak and stick with the T2 prism with 2 inch fittings either end. That would be showing a very respectable 2.3 degree true field

Unless you move to the 3 inch size of eyepiece, the 41mm Panoptic is as wide as you can get as I understand it. The Panoptic 41 has the maximum field stop size that can be accommodated within the 2 inch barrel format.

A few years ago I owned an Intes 150mm F/6 mak-newtonian with a central obstruction of 19.7% and no secondary vanes of course. It was a really excellent planetary and double star scope which also could do rather well when observing deep sky objects because of it's relatively fast focal ratio. I then acquired a very nice Skywatcher ED120 refractor, as it happens from the same person that I had bought the Intes mak-newtonian from. For around 6 months I owned both of these fine scopes and had plenty of chances to compare their planetary and deep sky performance. On the planets, I found that the ED120 was the equal of the 150mm mak-newtonian but on deep sky objects the additional aperture of the Russian made Intes scope allowed it to have an edge. In the end I parted with the mak-newtonian, with some regrets and kept the Skywatcher ED120, which I still have today. The mak-newtonian was a lot heavier than the ED120 and took longer to cool down and those two factors were what swayed me at the time. The relevance of this is that I feel that a good 120mm refractor can equal of a good reflecting system (the Intes MN61 is a very good reflecting system) of 150mm aperture for planetary observing. It would be interesting to compare one of these new 6 inch classical-cassegrains to see if my experiences comparing the ED120 with the MN150 are replicated or maybe, differ

Yes, I think that might do the trick.

Unless you have a big, fast dobsonian, I think the APM will hold it's place. Are you still using the Antares 1.6x barlow ?

Thanks but I'm not sure it works like that

Sorry but I don't know what an imaging circle is - I'm purely a visual observer.

I my case the scope will be 100mm F/9.