John

It will be interesting to see if designs change as a result of this. I have completed it as well. In the past Al Nagler has not been keen to remove undercuts when asked the question but I believe that he is at least partially retired now so his son and others may have more influence. I have to confess that I don't find undercuts a particular problem but for the sake of others I did say in the survey that they should be re-considered.

Removing the finder, racking in the focuser and separating the tube from the mount are the usual steps for transporting a solid tube dobsonian by vehicle. It is also the one time that I used the collimation locking screws as well. The collimation will almost certainly need re-adjustment before use at the other end of the journey though. Hopefully it will not be too far off if the locking screws have done their job. No need to over-tighten these screws though - Orion Optics used to have a sticker on theirs that said "finger tight only".

The clouds have cleared away here so I have managed a bonus view of Jupiter just before it dipped below the roofline of our house. Ganymede was just starting to exit the jovian planetary disk so there was a slight "bump" on the western limb but otherwise I was presented with the unfamiliar sight of Jupiter sporting just the one Galilean moon (Callisto) with Io having moved behind it's parent planet. Europa was well in transit and not visible to me against Jupiter's disk. Looking at some of Orion's binary stars, the seeing seems to have gone downhill somewhat so I doubt that Sirius B will b "on" tonight. I might give it a try anyway though 🙄

Clouds have now intervened with the observing, annoyingly. I got as far as Europa just starting it's transit and still visible against Jupiter's limb, as is often the case with such events. My guess is that Europa will quickly become very tricky to see against Jupiter's surface as it moves across the disk. Ganymede was visible as a bright spot for at least 50% of it's transit but has now become very tricky to see. I suppose the moon's illumination by the sun can vary slightly as it moves in it's orbit and the angle of solar illumination, relative to our vantage point changes. It may also be (likely, really) that Jupiter's south polar region is not an even albedo across the diameter of the planet so the visibility of a transiting moon against it will change as the transit progresses. All interesting stuff and very enjoyable to watch. One effect that was noticeable to me tonight was shortly after Ganymede started it's transit and while clearly visible against Jupiter's southern cloud tops was that both the moon and Jupiter seemed to "pop" into 3D. They both looked like the spherical objects they are with one in orbit around the other. The solar system in action in real time 😁

It's bright currently (sorry Stu !). Brighter than the background cloud tops. It's transit is across Jupiter's far southern polar zone though, which is a bit darker than the STZ to the north of it. Europa is going to start it's transit at 22:02 but further north so it will be interesting to see how that appears.

Still lovely here - very good views as Ganymede starts it's transit 🙂

It's still nice and clear here but will it last ???? 😬

The 100mm is delivering good views. So good, that I was moved to try a sketch, which I don't often do:

I'm just watching the GRS transit with my 100mm refractor. The GRS is nicely defined although it's colour seems a little muted this evening. The seeing here is also quite decent so 150x-180x proving useful.

I never found the dust lanes too obvious with my 12 inch. I see them more clearly with my 4 inch F/6.5 refractor and the 31mm Nagler under a really dark sky - 3.8 degree true field 😁

I agree with @Stu, Messier 31 looks better with a smaller, wider angle instrument or even large binoculars. When I had my 12 inch dob I spent many happy hours searching out smaller galaxies and galaxy groups though. Andromeda (the constellation) looks great with the naked eye of course 😉

The low altitude that Sirius reaches in the UK certainly does not help this challenge. I guess that from parts of the world where Sirius rides high in the sky, spotting the Pup is somewhat easier ! They probably wonder what the fuss is about 🙄

Jupiter's disk features do not respond well to the very high magnifications that can be used on Saurn and the Moon, for example. Generally I've found 130x-160x has delivered the best contrast on the giant planet on nights when 200x plus has been good for Saturn or the Moon. So "throttling back" the power is often a good approach 🙂

As long as you can get a sharp image in the central region of the field of view, you should be in with a chance. In terms of the separation it is not a difficult split - around 11 arc seconds currently so similar to Rigel and it's companion. It's the brightness and glare from Sirus A that creates the challenge with the much dimmer (10,000 times dimmer in fact) "Pup" star usually glimmering through the haze of light that surrounds it. Here is another interesting, and recent, piece on this challenge: Sirius B: Now is the best time to see Sirius’ companion (earthsky.org)

Unless the seeing conditions are really good (which is rare) you will only get the occasional glimpses of what your telescope is really capable of. These can only be momentary lasting a second or two. That is why you need to spend quite a lot of time observing a target such as Jupiter - you get more chance of seeing one of those fleeting moments. Our atmosphere is responsible for these variations.

Congratulations on getting "the pup" with a 4 inch frac 🙂

Here is a sketch I made a couple of years ago using my ED120 refractor. The Pup star has been to the E and slightly N of Sirius the the past few years and trails behind it as Sirius drifts across an undriven field of view.

Interesting. My perception of the colour tints of these planets is similar to @Stu's and @Saganite's. Generally I would describe Neptune as pale blue. When I have observed either planet close to the Moon, the colour tints seem to be noticeably stronger. I often wonder if younger observers eyes are more sensitive to colour tints ? - that often has been the case when I've been sharing the views at outreach events.

Apart from the 17.3mm and 14mm Delos. Those need around 10mm inwards focuser travel to reach focus.

I've never noticed the "coffee tone" on those eyepieces either. Some eyepieces do have a slightly different tone to the views but I haven't found those variations annoying or distracting. The only Panoptic that I have owned is the 24mm and I don't find kidney beaning an issue with it myself. As you so rightly say though, eyepiece preferences do seem very personal. Perhaps more so than most other items of equipment. I guess that is because the eyepiece creates the connection between the human system and the optical system and that intimacy makes us very sensitive to their characteristics and how they match (or don't match) ours 🤔

If possible, it is best to keep optical accessories such eyepieces, filters and barlow lenses slightly warmer than the outside temperature. If they get too cold they have the tendency to fog as you use them from the warmth of your face and eye socket. For non-optical accessories your flat shelf could be useful.

Without such setups I think I would have given up observing a while back !

Lovely scope Andy Hope your clear skies last a bit longer - mine have been replaced by fine rain now 🙄

Curses !!! - fine misty rain now and gradually tuning into something steadier. I was enjoying that as well 🤨

Back out again now, fed and watered 🙂 Still clear skies here and still good seeing. The detail showing on Jupiter is really very nice indeed this evening