John

Thats why forums like SGL can bs so useful - just keep asking the questions, there is a heck of a lot of experience on here

A 4 inch achromat has to have a focal ratio of F/15 or so to show no false colour visually. At around F/10 the amount of false colour is really quite small so that is a popular focal ratio because the scope tube is manageable (ie: not too long). The achromats that operate at F/5 or F/6 do show quite a bit of false colour but their main intended use is for low to medium power viewing of deep sky objects and in this they do a good job. There are filters that reduce the amount of false colour that is visible but they do tend to add a noticable tint to the image. Some people find them useful and some don't like them. A 8 inch F/6 newtonian will show no false colour at all and is likely to show excellent planetary views.

If you use a 40mm 68 degree 2 inch eyepiece with the 115mm F/7.8 refractor you will get a 3 degree true field of view. With a 6 inch F/5 the same eyepiece would create an rather large exit pupil which would not be as effective IMHO so you would need to reduce the focal length of the eyepiece to something like 30mm. With a 30mm 82 degree eyepiece the 6 inch F/5 would show you a true field of 3.3 degrees so not a lot more than the 115mm F/7.8 can muster. Depends whether you feel that the relatively small additional field and some additional light grasp is worth owning another scope for

The Tele Vue 32mm plossl is very nice quality but it does not have a wider field of view than any other 32mm eyepiece in the 1.25" format. Just worth being aware of that.

I've been there with the TV Naglers and the Plossls owning full sets of those for a while. But I also don't like to see an expensive piece of kit not getting used so that overcame the desire to hold on to full sets. Incidently the 17.3 and 14mm Delos are not par-focal with the others in that range. For me thats good because it means that they fit nicely with my Pentax XW's and are close to par focal with them but I know that it does slightly annoy those who have full sets of Delos. I said to my other half just a while back that I didn't think that I was OCD with my eyepieces these days. She gave me a funny look and said "Really ???"

Hmmm, maybe not then ? If the original poster could do without slow motion controls the AZ-4 would do the job well as mikeDnight and paulastro have said.

Scope fettling - the ideal antidote to a rainy evening If this weather keeps up, we will all have the best collimated, most highly polished and optically clean instruments anywhere on the planet !

Just been going though mine. Rather surprised to find: 8x21 unbranded 10x25 unbranded x 2 (pair in each of our cars) 8x30 Carl Zeiss Jenoptem x 2 (one old pair and one newer pair) 8x30 Swarovski Tirol 8x30 Komz 8x32 Opticron Adventurer Roof Prism 8x40 Helios Naturesport 10x50 Helios Naturesport 8x56 Opticron Vega II 11x70 Opticron Oregon LER Where do they all come from - must breed in the cupboard

I find Polaris is a good star for star testing. Bright enough but not too bright. Easy to find (from where I am anyway) and it does not move (much) when being observed. A green filter can be used to better discern the diffraction ring / airy disk pattern.

I agree. It's a good mount but the stock clamps are poor. They should have upgraded the clamps to a better design ages ago I reckon. The reason why folks put up with that and upgrade the clamps is that there is not much that competes with the Skytee II in terms carrying capacity vs price. For the 2 scopes that you are considering though, the 1st of the mounts that you posted links to should do the job. This UK supplier has something very similar on sale currently: https://www.365astronomy.com/365Astronomy-AZ5-Versatile-Vari-angle-Micro-Motion-Alt-Azimuth-Telescope-Mount-with-Stainless-Steel-Tripod.html

I have a Feathertouch on my 130mm F/9.2 triplet refractor. It is superb in every respect. I like the Moonlites and have a couple of those but the Feathertouch is in a different league again. Pricewise too, unfortunately !

I have seen both above mounts and used the top one briefly but I've no long term experience with them. From what I've seen I would agree that they are both a significant step up from the AZ-3 and probably the AZ-5 as well. I would be more attracted to the 1st one that you link to because of it's steel legged tripod. Heavier but a lot more stable than an aluminum tripod and it will resist the twist force that a longer tubed scope creates much better which = less vibrations and more stability. The Skytee II mount is also available from that vendor and that is a very steady mount even with an ED120 F/7.5 on board. Another step up the ladder in terms of solidity and capacity. And cost of course: https://www.teleskop-express.de/shop/product_info.php/info/p4537_TS-Optics-AZ5-Azimutale-Montierung-mit-Stativ-und-Feinverstellung.html

I've had a couple of clear hours here so I've been able to have a session with the Rowan AZ100 mount. Clouding over now so thats it for tonight I think. I'll get onto writing up some notes .....

Once you have fitted the Moonlite to the Bresser, if you want to move it to another scope it's just a case of changing the flange. The rest of the CF2 focuser unit is standard.

It's not the weight so much but the length of the scopes that stresses the mount. The AZ-5 might be OK with the F/7. I have doubts as to how suitable it would be with the F/9 but it might be OK. The stock tripod of the AZ-5 is not too stable so a tripod upgrade should be strongly considered.