John

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.

The F/9 will not be held steadily by an AZ-3. The F/7 would be pretty marginal as well I'm afraid especially if you try and use the sort of magnifications that these scopes are capable of. An AZ-4 would be much better.

If the objectives are figured to a similar quality (which is likely) then there won't be a lot of difference, just a touch more false colour around bright objects and possibly the F/9 might be able to handle higher powers wiht a touch more aplomb. I have a 102mm ED doublet that works at F/6.5 which I think uses an FPL-51 element but the false colour is not intrusive at all. A well figured F/7 ED doublet is a very versatile scope being able to handle both high powers and deliver wide fields of view at low powers

I believe the TS 102mm ED (non-Photoline) uses an Ohara FPL-51 glass ED element. What type of glass the mating element uses is not defined. The F/9 100 ED uses an Ohara FPL-53 element mated with a Schott glass element. The levels of false colour visible in the F/9 are very low indeed from what I recall when I used to own one. The TS 102 that uses FPL-51 will be a lot better in terms of colour correction than an achromat of that aperture and focal ratio but is likely to show a little more false colour than the F/9 Skywatcher. As Stu says, the F/7 will enable a wider field of view to be delivered and the focuser is likely to be better than the Skywatcher. Depends on your priorities I suppose ?

A decent quality barlow lens, on average, reduces light transmission by 1-3%. That is less than the variation in light transmission that is found across different eyepiece designs / brands without a barlow lens in play.

I use the Baader T2 Zeiss prism with my Takahashi FC-100DL and it works very well. I also have a couple of Tele Vue Everbrights and an Astro Physics Maxbright which I also think highly of. The Baader T2 suits the slim lines of the Tak very well but in all honesty I've yet to see any optical difference between it and the Tele Vue and Astro Phiysics mirror diagonals when I've swapped them about on my refractors I have read BillP's reviews as well, more than once I have to say - they are good reads

These are all the flanges that Moonlite do for various refractors. My suspicion is that they won't have one currently with the Bresser AR127L name on it but one of the others is probably the right one, either a Meade or an ES probably because those brands have had strong connections with Bresser products. The question is which one precisely ..... https://focuser.com/refractorflange.php If you can get the flange sorted out, the rest is easy

The Skytee II should handle an ED127 triplet OK if it is on a sturdier tripod than the stock 1.75 inch one. A 2 inch steel tube legged tripod or even better a Berlebach Uni should be investigated. Even then you would probably have some vibrations to deal with at higher powers I reckon.

Its worth remembering that prospective UK buyers (and maybe EU ones as well ?) should factor in import duty and handling costs as well.

In my opinion a 100mm ED doublet would have the edge over an ST120 for white light solar observing with a wedge. I use my Lunt wedge with my Vixen 102mm ED and Tak FC 100 and the results are really good. On double stars I think it would be a close run thing but personally I feel that good ED doublet refractors have provided the most satisfying views of double stars of any scope types that I have used. On lunar observing, again it would be a close run thing between a good ED 100mm doublet and a 127mm mak-cassegrain.

A quick "bump" for this heads up. More info on UK observation here: https://www.popastro.com/main_spa1/transit-of-mercury-2019/

The trouble is that the GOTO function eats up a lot of a £350 budget leaving proportionaly less for the scope itself wheras without GOTO that budget would get you firmly into the 200mm aperture class. It's a tricky decision I grant you.

Interesting thoughts Doug Lots of clouds and rain do tend to prompt this sort of review. That, and lots of equipment tinkering ! The only thought that I have to offer currently is that refractors seem to get quite a lot larger and harder to mount steadily when they exceed 120mm in aperture.

Yes, with an eyepiece. I've not actually used one though but I've read about the need for quite a lot of inwards focuser travel with this coma corrector frequently.

That still looks quite a large CO though ?

I agree with Dave - for purely visual observing I would always prefer to have that additional 22mm aperture.