John

When I moved from an 8 inch SCT (Celestron) to a fairly ordinary 8 inch dob (GSO made) I was surprised how the much less expensive dob could produce images of the planets and deep sky objects that were as good if not better than the SCT could manage. My current 12 inch dob (Orion Optics) has a 21% obstruction and high quality mirrors. Good combination I find I agree with the point made earlier regarding SCT collimation. I've looked though a few other peoples SCT's and found them not in collimation. I have to confess that I didn't feel able to mention it at the time because their owners were enjoying the views. One C8 that I looked through could barely split Epsilon Lyrae. With a largish central obstruction I think that collimation needs to be accurately maintained and the contrast and sharpness of the image goes down hill sharply even with relatively small amounts of mis-collimation. I recall that Thierry Legault's website illustrates that rather well. I used to have a 152mm maksutov-newtonian which had a CO of around 18% and no secondary supports. The images through that were really contrasty and sharp - the closest to an apo refractor that I've seen from a reflecting system.

That's the AZ-5 pillar extension isn't it ?

My Dad used to drive Alfa's. He said you could watch them reverting to Alfa Particles when it rained.

Tele Vue stickers are useful for covering up marks

No additional weight in the Skywatcher as far as I know.

I've edited that down by two thirds for you Alan : "It's a fine snob, I have not seen light for most of my time, I have been awful of late, better Hope you can understand I clearly can't." Makes perfect sense now

The scope is a TMB/LZOS 130mm F/9.2 LW triplet. The FT focuser is standard on that model. I now know why FT focusers have the reputation that they do

I had a couple of the 127L's (one was branded Meade and the other Bresser but they were identical). The collimation needed adjusting when the Meade arrived but the Bresser was in a better state. I did tweak it a bit but I quite enjoy doing that and the objective cell makes it straightforward. If the focuser is out of true it's harder but that was not an issue with the units that I had. I would use a counterweight with the Skytee II and the 127L. Any type with the 20mm central hole will fit. Not the full weight of the scope, just a few KG to keep the azimuth axis motion smooth. Definitely replace the DT clamp on the side that you are going to put the scope on. I use the ADM clamps. The top saddle is suitable for short lightweight scopes only IMHO. You may want to think about a taller tripod at some point unless you are going to be sitting when observing. This scope is about the same size and length as the 127L, maybe a touch heavier (9.5kg):

This thread is morphing into "show us a bit of your dob" Interesting to see these different approaches though. Meade used to stick a great lump of cast metal just behind the primary cell to counterbalance their dobs and newts. The problem with that was it increased the thermal mass around the mirror which slowed down cooling a lot

Antares is a "between the houses" job for me And of course it's tint is usually "augmented" by the amount of atmosphere we have to view it through from the UK.

I've not done the job myself so I can't help with the grease type Steve. Others will not doubt suggest what to use soon though

My dob is in tube rings so could be shifted up and down as well but that would not be enough and also the travel downwards I have is limited because of the way I have the scope setup for my eye height. I have a number of eyepieces that weigh well over 1kg so they do need counterbalancing when the scope is pointing below around 60 degrees. Its become second nature for me now Whatever works for you though. I just thought I'd post the pic to show one fairly easy way to do it

Great stuff Geoff Tough targets, that rille and the craterlets, or at least the ones beyond "the big 4". Seeing needs to settle to get those elusive glimpses. Well worth the effort though and thanks for posting the report

Here is a link to the Skytee II stripdown guide. Mine was done just before I bought it: Skytee2 strip.docx If it was bought new, it might be worth checking the warranty situation if you do this ?

That's a great counterweight solution for a steel tubed scope My Orion Optics 12 inch has an aluminum tube so I've gone for a knife rack, some screws through it to create little shelves in 2 positions along the rack, and a couple of old TAL counter weights of 750g and 1500g. Gives me lots of "quick change" weight options depending what I have hanging out of the other end and also depending on the angle that the scope is pointing at

I think posters need to feel free to post in the style that they like. I have always found Alan's reports clear, interesting, comprehesive and accurate. We are very lucky to have people prepared to compile and post detailed and independant reviews like this on the forum.

A new report connected with this topic from UCL: https://www.theguardian.com/science/2020/jun/29/dinosaurs-wiped-out-by-asteroid-not-volcanoes-researchers-say

According to the spec the tube is aluminum. Must be pretty thick stuff ? An 80mm F/10 doublet is not going to have thick glass elements so much of the weight must be elsewhere. Does it have solid gold baffles ?

Sure does - it weighs nearly as much as my ED120 !

A few years back I was loaned a 10mm XW by First light Optics. I compared it with the Nagler T6 9mm that I had then and found the 10mm XW, although having a smaller field of view (of course) was a touch sharper, had less light scatter around bright objects and presented a "whiter" view of bright objects. I loved the Nagler T6's so I was very interested to find something that was a touch better. I now own a set of both Delos and XW's and use them one after the other during sessions. For me they are practically identical in performance. The Delos costs £87 more than the XW here in the UK.

Wow ! - I didn't realize that the StellaMira 80mm F/10 was that heavy. My Tak FC100-DL weighs around 4.5kg fully loaded. It's a bit longer though. I'll be interested to hear how you get on with it

The scope and eyepieces are in the ones at the back. All the others are Dave's sandwiches

When I last owned a Baader 8-24 zoom (I think I've owned 3 over the years !) I generally liked it and was expecting the narrower AFoV at the long FL end of course. What I found slightly annoying was that the field stop edge was rather fuzzy and ill-defined at the longer focal lengths as well. It's a small thing but I do prefer a sharp field stop in my eyepieces. I guess with a zoom the field stop is moving with the lens elements so to expect it to be razor sharp right across the range of FL's is a big ask

Antares ?:

It is not my scope it was just photo of a 12 inch refractor that I found to illustrate my point about the difference in practicality between a 12 inch dobsonian (which is my scope) and a refractor of the same aperture. There are not many 12 inch refractors around outside of observatories. The 12 inch refractor is F/12.2 and was for sale a while back (might still be available ?) in the USA. Here is a movie all about it: