John

I've not caught up with this thread for quite a while - some very nice Vixen's on show. That 115mm is really rather something and it looks a perfectly balanced setup with that SXD2 mount 👍

On my 12 inch dobsonian I used a Rigel Quikfinder alongside a 9x50 RACI optical finder. Coupled with wide field eyepieces this approach has provided a decade of satisfying observing with some challenging targets located close to the observing limit for the aperture where I observe. On my refractors I use RACI optical finders for the majority of the time but occasionally I use an illuminated reticule finder. Top end of my 12 inch dob:

Thanks Alan. I'll use the forum search facility and see if I can find some reports. I don't wear glasses when observing and find 12mm and upwards eye relief fine but I can understand that more than that is required if you do wear glasses.

Good solution ! Baader publish accurate light path lengths for their products so you should be able to work out quite accurately if there will be much of a difference over the Tak 1.25 clamp in that area.

If you have back problems do take care when considering a 12 inch dobsonian. If you could see one "in the flesh" that would be very helpful I think. I used to have a 12 inch Meade Lightbridge which was a similar size and weight to the 12 inch Skywatcher and Stellalyra. I had some mild back issues at that time and found the weight of the 12 inch Meade just too much so it did not get used after a surge of initial enthusiasm. I later managed to get a 12 inch dob based on the Orion Optics optics and tube with a custom made plywood mount and that weighed much less and therefore got used a lot more. 12 inches of aperture is very potent but not if the whole thing proves hard to manage. If you have all this covered then that's great and I'm sure you will love the views 🙂

Also North Somerset. Nothing on show here either. Go for the nectar is my advice 😁

The combination of scope and location is rather special 🙂 The Yosemite Valley and Half Dome mountain I think ?

I used to use my 12 inch dobsonian at 300x plus without a tracking equatorial platform. The EQ platforms are nice to have but not essential from my experience.

Apologies if I have missed some discussion on these but I wonder if anyone has them and, if so, what they think of them ? I'm just "tyre kicking" really - pondering the option to move from my current mixed collection of Tele Vue and Pentax eyepieces to a simplified all Pentax line up of: 23mm, 16.5mm, 10mm, 7mm, 5mm and 3.5mm. I already have the 4 shorter focal lengths in the series. Each time I think about "rationalising" my eyepieces I seem to talk myself out of it but I'm feeling a stronger will to actually make some moves now and a Pentax XW set, although not perfect (of course) would seem to be a pretty good compromise to happily live with based on my experiences with the XW's that I currently own. I suppose the main thrust of my question is to find out if the new 85 degree Pentax's have any major issues that I ought to be aware of. I don't wear glasses when observing Thanks in advance for any feedback 🙂

The year before last we spent a week in a tiny hamlet in the middle of Dartmoor. No lights for miles around and the darkest skies that I have experienced for a long time. I had 11x70 (Opticron) binoculars with me and had a lot of fun cruising around the summer sky. I can recall seeing Messier 13 with the naked eye and M31 was really clear without binos. The milky way extended practically across the whole sky and it's dark rifts were very apparent. The binoculars showed me a number of galaxies including M33 quite easily, dozens of open and globular clusters and the eastern portion of the Veil Nebula. The North American Nebula near Deneb was quite clear in the binoculars as well, especially the "gulf of mexico" part and I glimpsed the nearby Pelican Nebula as well. I did not use filters although it is possible to use them with binoculars I believe. The density of the star clouds in and around the milky way were quite something and showed how dark the skies were. Even my other half was very impressed with those skies and it takes a lot to do that ! Well worth taking decent aperture binoculars to dark skies. Goodness knows what the views would have been like with something like an 8 inch dob if I had managed to get one of those down there 😲 Take a decent sky atlas as well to show you "what is up" when you are there.

I have 102mm F/6.5 and a 100mm F/9 refractors in the 4 inch class. Mostly I use a 1.25 inch eyepiece set as follows: 24mm Panoptic 14mm Delos 10, 7, 5 and 3.5mm Pentax XW's 4-2mm Nagler zoom For wider angles of view with the 102mm F/6.5 I have a 31mm Nagler plus 21, 13, 8 , 6 and 4.7mm Ethos's which are used in 2 inch mode. So two eyepiece sets, which is admittedly rather extravagant 🙄

Try fibbing about your location. Tenerife looks good 😁

That is looking much better to me 🙂 On the distance to put an artificial star at, it's difficult to find any precision in this. I've seen figures that vary between 40 and 100 metres. I guess the further away it is, the more the artificial star will appear like a real one.

This is what I look for in the cheshire: My (probably limited) understanding is that you should check for focuser tilt first (using the laser) and address any that is there. Once you have the laser exiting the centre of the objective, re-test with the cheshire. If you still get something like the right hand image above, the objective has some tilt that needs to be addressed. When I've star tested refractors where there was either focuser tilt or objective tilt (or both !) the diffraction rings are not concentric around the airy disk but offset to one side or another. A bit like this:

That looks like the optical axis of the focuser is not aligned with that of the objective. Moonlite focusers have collimation adjustment I seem to recall so you should be able to get that laser spot central. It might take some trial and error though.

Unfortunately there is no collimation adjustment on the ED120 objective cell. The trick of loosening the lens retaining ring (scope pointing upwards) and gently slap around the cell to settle the elements, as suggested by @wookie1965 is worth a try. If the objective as a whole seems to be tilted then you could check that the cell is not cross-threaded where it screws onto the scope tube.

If possible it would be worth hanging onto the Starfield ED 102 and comparing it directly with the Tak for a while. A report of your findings would make interesting reading on the forum 🙂

Interesting report and photos. I think OO are being harsh on Skywatcher mirrors - I've owned 3 Orion Optics newtonians (tested as 1/6th, 1/8th and 1/9th wave PV) and a number of Skywatcher ones and not found significant differences in optical performance - "subtle and slight" would be my description. Some nice looking OO scopes though 🙂 Enjoy your VX6L when you get it 🙂

Yep - I found a 6" F/12 too much of a good thing when I owned one 🙄 It made an EQ6 on 3 inch steel tube tripod legs seem quite puny !

My finders crosshairs have a number of orientations - I tend to agree with @Mr Spock, that this does not matter as long as the centre of the X is correctly aligned. You should be able to unscrew the eyepiece section a little from the diagonal body and the cross hairs will rotate with it because they are attached to a reticule within the eyepiece section, set at the focal plane of the eyepiece. If you unscrew the eyepiece section a little you will need to adjust the focus of the finder again which is done at the objective end as you probably know.

The mount for my 12 inch Orion Optics based dob was made from 18mm baltic ply I seem to recall. It was very stable and quite light at about 10kg.

Higher speed impact, ejecta launched further from the surface and took longer to fall back so lunar rotation plus other gravitational effects caused a more untidy final surface distribution of ejecta ? Further smearing / distortion caused by tectonic activity triggered by the impact ? Just guessing here !

I noticed that AP scope on e.bay and wondered what it went for. This old AP catalogue covers that model I think: 880315.pdf (astro-physics.info)

Oh, I don't know - we visited the eastern side of Australia for a month in November 2018 and only had 3 clear nights. The days were wonderful but lots of cloud at night. Luckily I had my 8x56 binoculars with me so that I could grab any clear time that did occur but if I had gone to the bother of packing a scope, it would not have got much use !

I've found Uranus and Neptune respond well to high magnifications, sometimes very high magnifications (ie: 400x or more). With my 130 triplet I've spotted Neptune's largest moon Triton at such high magnifications. Your 140mm should be able to spot that and maybe even a couple of Uranus's moons on a dark night 🙂