Geoff Barnes

Regarding the truss tubes, they have two positions. When you extend the telescope from its compact state the tubes will click and seem to lock into position. This is not the full extent, you need to pull the scope past that first click lock another few inches until it will go no further, then it is in the correct extended position and any eyepiece will come to focus. I have had my truss Dobsonian for three years now and still make the mistake of not extending the trusses fully on the odd occasion and wonder why I can't focus on anything.

Good grief, Mr. Tings must be a single man, if not I reckon he soon will be! 😲

John's got to build a shelf first to put it on in his dining room. 🤣

How is that Peter? Also, will your new finder have its own finder as well? 😆

Thanks for dragging that old post of mine up @Ags, that was almost one year ago exactly and brought back fond memories of a great evenings viewing. I'm hoping to repeat that comparison when Jupiter and Saturn come into view above the trees in about another month or so. I will also give my new SLV 2.5mm a shot at Saturn just for fun, 600x mag through my 12 inch Dob should be revealing if conditions allow!

Hi Armaan, I am in Australia and Jupiter here rises very high in the sky in the early hours of the morning and is very sharp and clear with great detail and colours visible. I am tending to think that your telescopes mirrors are badly out of collimation. Have you checked them since you got your telescope?

Finally got a couple of clear nights this week and was keen to get a proper first light with my Vixen SLV 2.5mm EP, which I bought way back in February. Sunday night was cold and clear and completely still and I was expecting perfect seeing for some high power views of the moon. Alas, while transparency was great (I gave it 10:10) the seeing was inexplicably very wobbly, even at moderate powers with the Baader zoom at 8mm (you just can never tell regarding the seeing). Plato was still just in shadow beyond the terminator so all my concentration was focused on the Alpine Valley which had just come into the sun's light. The shadow of the southern rim was nearly half way across the valley at the western end, tapering off at the other end to almost nothing so conditions were right for a good chance to see the Alpine Rille. I had the 12 inch Dob in tracking mode so the Valley filled the centre of my FOV and stayed there. I had my 4mm SLV in first giving 375x and this gave occasional tantalising glimpses of the western end of the rille when the seeing steadied for a second or two, but was just too wobbly for anything more. Replacing it with the 2.5mm SLV yielding a crazy 600x magnification naturally produced terribly shaky seeing, but the image was obviously much larger now and I persevered for a couple of hours just hoping for a steadier view. I would reckon I had three or four chances each for a few seconds in which I'm sure I could see the rille all the way along the valley, but the glimpses were so brief it was hard to be sure. Monday night produced equally clear cold and calm conditions and out I ventured again, this time knowing Plato would be in view. I had never seen the Craterlets before and this was to be my goal for the evening. Centred on axis again in tracking mode I again used the 4mm SLV to begin with and again the seeing was frustratingly wobbly, not quite as bad as the previous night though and almost instantly I could see the crater floor of Plato was not smooth as it had always appeared to me in previous sessions. In steadier moments I could make out A,B,C and D craterlets and thought I could see E over on the left but not sure, F was in hidden in the long jagged shadows cast by the crater rim walls. Swapping over with the 2.5mm again the view became more wobbly but with perseverance I was thrilled to see the four main craterlets as obvious circles and E craterlet for brief seconds appeared as a white dot. Poor seeing didn't allow any more to be seen but I was happy with my haul. What was also nice to see was both Plato and the Alpine Valley in the same FOV with the SLV's and I enjoyed switching my gaze from one to the other. The Alpine Rille was in much more sunlight now and it was harder to see with less shadow, though there were hints of it as the thinnest white thread in the steadier moments. So all in all a successful foray and I can't wait for a chance to return to these wonderful lunar features with the benefit of rock steady seeing when I'm sure the SLV's will deliver the goods. It was just so good to be back out observing again, opportunities here in winter are few and far between up on the mountain.

A bit of a dilemma for you @John, where on earth will you put your next scope without upsetting your better half? 🤔

Hi @johninderby, have you considered the Baader Morpheus 4.5mm? If it is anything like the 6.5mm that I have it would be a great one to try. I've been hovering over the "Buy" button for months now, just waiting for the exchange rate to improve in my favour.

Aha! Now this one should be within my grasp. Lyra is upside down here with Vega at the bottom and Gamma Lyrae at the top, so the seeing should be better than it is for the Double Double which hugs my horizon. Thanks @John👍

This observer in the Philipines got really lucky with a shot in a million as the ISS crossed the sun during yesterdays eclipse...

Barry, is that big spike visible to your eye or only when you use your camera, could it be a camera artifact?

Yes I have, I replaced it with this dual speed upgrade kit and am pleased with it, good solid quality and simple to fix... https://www.365astronomy.com/Lacerta-Dual-Speed-1-10-Microfocus-Upgrade-Kit-for-Skywatcher-Crayford-Focusers.html

I know what @Barry-W-Fenner means regarding bright stars with a 300mm Dob, I get the same affect with mine. It is only noticeable with the very brightest stars like Sirius, Arcturus, Vega etc. which do show a kind of bloated form, even with perfect collimation. All the dimmer stars do exhibit as pinpoints of light. It is just the nature of the beast with a 300mm SW Dob.

Blimey @djpaul how tall are you? You're bending down to look through a 300p that is nearly vertical. 😮

Yes, news to me too @John. Did you see I featured this in my post in the Observing Atlas Y4 thread?

This is interesting, from NASA's Stereo HI-1 Satellite Camera showing Comet Atlas Y4 passing the sun. What I found most interesting however was that Mercury too has a "tail" like a comet! Who knew?

Hi @alacant, no it certainly is not acceptable. You have every right to expect it to be in perfect condition. A replacement mirror is essential.

I've been having a bit of "double trouble" with Tegmine lately. Having recently had a couple of good sessions spying doubles I found the very tight split of Porrima quite easy at 175x helped no doubt by its high altitude here (about 65 degrees). So I've been turning my attention to Tegmine to see if I can split the very tight 3rd star which I've not seen before. Tegmine is sinking rapidly down to my norrhwest horizon between two trees just after sunset so time is running out. Thursday evening I had the scope set up in what I thought was a good position but frustratingly the tree on the right obscured my view to the,extent that I could make out the A and B stars very fuzzily, no hope of C at all. Undaunted I set up slightly further left on Friday after sunset confident of seeing them. Dammit! This time the stars had just disappeared behind the tree on the left! The weather is turning offensive again now for a few days, but I am determined to try again next week before it becomes impossible for this year. At least if I fail I will have the Double Double in Lyra to try for soon, a real tough one here as they are very low on my north horizon and rather shimmery at best.

@Barry-W-Fenner I find my short Cheshire shows the primary clips better than my long one. Also racking the focuser right in and out until all three are visible helps.

Yep, same here with my 12 inch f4.9 Dob. Fine tune the primary mirror with a star test using a high power eyepiece and all done. Cheap as chips,simple and effective.

I found collimation easy from the get go, but I know a lot of people struggle. A bit like riding a bike, once you get the hang of it it's easy. We can suggest some of the best online tutorials to help you if and when you need them.

Hi @mil5nov, how long have we got to solve your dilemma for you (ie. when is his birthday)? I don't have experience with any of those scopes, normally I would say go for the biggest aperture of the Dobsonian, but they are not really suitable for photo astronomy, so I'll leave it to forum members with relevant experience to offer advice. Good luck!

Hello again David and welcome back. From Southampton myself and we always referred to ourselves as good old "Hampshire Hogs", maybe to do with the wild pigs roaming the New Forest perhaps?

I have the same scope Barry (with goto) and unless money is no object to you I think you won't do better than the Baader Morpheus EP's, high end quality at a very reasonable price.