John

X-ray's help to see whats going on inside without intrusive surgery. Some of the lens surfaces inside the more complex wide fields have serious curves on them !:

I've used all the LVW's but I agree that the 22mm was the pick of them. The others are pretty good as well The 22mm LVW is on my "wish I hadn't sold it" list, along with a few others ......

My society has one of those - except that it is the 18 inch

Economy measures and solar observation are not a sensible mix IMHO.

Oh, that is very different then. It's been a long time since I've had the 6mm so I could not remember what it looked like from beneath ! I wonder why the design was changed ? I'll guess and say that the longish tube acts like a light baffle to keep stray light away from the optics.

No harm in having a look to see if things can be improved a bit further These are the 3 that I was sent to review: Have they changed the design of the 6mm then ?

Interesting stuff. The Baader Classic Orthos that I've tested and owned have been pretty good eyepieces. I didn't notice any issues with light scatter or transmission so it will be interesting to see if the improvements you have made result in noticeable improvements in performance. The only issue I had with the 6mm was a slightly fuzzy field stop. Not a big issue and it doesn't affect peformance but I found it a little annoying. The BCO 10mm is regarded as one of THE best deep sky eyepieces by folks who use huge scopes under dark skies in the USA so Baader certainly knew what they were about

My 12 inch dobsonian is the probably my most used scope. I observe 99% of the time from my back yard under moderately light polluted skies in the outskirts of a large town. Mine 12 inch weighs around the same as a Skywatcher 10 inch though which helps a lot with portability. I had a 12 inch Meade Lightbridge a few years ago which was very heavy and unwieldy. I'm not likely to go any larger though, unless we move house and I can setup an observatory or roll-off shed. If I lived in a flat / apartment with no easy and level access to a garden I might well have settled for something smaller. Where I observe is just a few paces out through the door from the room where my scopes are stored. I can have my 12 inch dob outside and cooling in about 1 minute. Knowing where to stop for your observing circumstances is the trick I think. Nothing worse than a fine large scope that is not getting used because it is impractical

Good call on the Nirvana's from Mike above. I can't believe the value that these are currently. When they first came out (William Optics UWAN's back then) they were expensive eyepieces, not quite Tele Vue expensive but getting on that way. Now they are not much more than BST Starguiders for something which is pretty close to Nagler performance

I have some telephone cables that run across my garden. Occasionally I've noticed a new bright diffraction spike on a star only to find that one of those dratted cables has strayed close to the field of view

Me too. At the very least they would have called it the "Plus" version or "Skymax Pro Mk II"

Thanks Gaz - I'm glad I was not imagining it ! So I wonder just what Synta / Skywatcher did actually change to increase the effective aperture ?. Maybe nothing and the tales of the 180's operating at less than 180mm are myths ?

The ES 70 would be OK in that scope but not outstanding in any way. It is quite an old design - a 5 element modified Erfle. The 68 degree ES range is a more modern and sophisticated design which works well even in quite fast scopes - I used on in my F/5.3 12 inch dobsonian and it was pretty much sharp to the edge of the field. I believe that the Bresser 70 degree eyepieces are the same as the ES 70's and the old Meade QX range are also the same.

If you wear glasses while observing I can see that the ES 12mm 92 would be good. I don't wear glasses though and found that I needed to "hover" my eye some way off the eye cup of the eyepiece which is not how I like to observe - I prefer to nestle my eye socket gently into a soft eye cup so that the eye cup keeps stray light off the top of the eyepiece and acts as a eye positioning guide. Because I could not do this with the 12mm 92 I let that one go to a new home. I still have the 17mm 92 though which suits me better although that has taken some getting used to as well. They are excellent eyepieces optically though, quite probably the best that ES have produced to date.

The ES 70's are not as well corrected as the 68's. If your scope is F/8 or slower they work fine. In faster scopes the 68's are much better.

I've seen a thread somewhere on the original gold tube 180 which showed that it has a primary the same diameter as the more up to date one that @Captain Magenta took apart recently. Is there some other modification that would increase the effective aperture such as a re-designed secondary baffle ?

Up to now I have not used a filter on this target either. Generally I prefer not to use filters unless they are going to make a sigiificant difference. But it is fun to try new things out

Guess what my first target is going to be when I next have the 12 inch dob out ? - the Cats Eye with the Lumicon O-III filter

Well, the image is as good as the weakest link in the optical chain. As long as the barlow lens is of good optical quality it's impact on optical quality should be negligible. The only snags that I can see are: - The 12mm ES 92 (which I believe you said you have) is a very large 2 inch eyepiece. Adding a 2.5x barlow to that will make a heavy and tall "stack" to hang out of your focuser. - The 12 ES 92 already has quite long eye relief and the barlow lens will extend that further. You might find that eye positioning becomes tricky ?

That sounds right. Its not much difference - 10% more:

Of those I think I would go for the Vixen 30mm NPL because I like it's ergonomics. There is not a lot between any of them though, even the BST 25 is not too bad in an F/6 scope like yours. I think I've owned all of them at one time or another

If you have the Nirvana's (the 16, 7 and 4mm ?) I don't think the ES 52's are going to offer you anything more. The 16mm Nirvana will show you quite a bit more sky than the 20mm TV plossl can as well.

If the mount for the finder is well designed it should slide on and off the scope and store while maintaining it's alignment accurately with the main scope. I use a similar 6 screw finder mount on my 130mm refractor and it holds the finder in alignment really solidly.

Not being a gamer or even in any sense a "power" PC user I didn't factor that in of course It sounds to me as if you have already talked yourself out of a Tak so that's the decision made

I think this is one of those "do what works for you" matters I think the original poster has bought a rather meaty finder scope (60mm ?) so it's going to be quite a projection while it's on the scope: If it gets a real clout the finder mount could possibly twist the tube wall ? - I've seen quite a few newtonian tubes where that has happened and the tube is slightly deformed where the finder mount shoe screws onto it as a result. One of the reasons that I remove my finders when the scope is not in use.