Ruud

Yes, a Bird-Jones design. That uses a corrector lens. If you remove the eyepiece, can you see a lens at the bottom of the focus tube? We've had a member with a missing corrector lens which made focusing impossible. Welcome, I hope we can solve your problem.

Thank you for responding Alexander. Part A - windowed mode The GL jagged edges problem only exists full screen. In a window everything looks fine. This is 0.19.3 open GL in a window at 150% scaling, it looks just fine: Part B - Full screen mode The problem only exists full screen. Please view everything at actual pixel size to get rid of the moirée. At 150% scaling the difference is obvious in the text and even in the constellation lines. It may be there in everything. zips of original pictures: 100% scaling ANGLE and GL.zip 150% scaling ANGLE and GL.zip At 100% the fonts look fine in both GL and ANGLE. The constellation lines are a little different though, but this is not obvious at a normal viewing distance. See the 100% zip. I'll be happy to do more testing if you want me to. NB. The pixels are about 0.15mm wide. I'm trying out purple constellation lines. I think I'll try dim grey next.

(Russian below / Русский ниже) Hello Alexander, happy 2020, now or if you prefer in two weeks. Today I tried stellarium 0.19.3 and noticed that anti-aliasing no longer worked. I use the program on a 4K monitor, with Windows font scaling at 150%. So I went back to 0.19.2, but the anti-aliasing did not come back. I installed 0.19.3 again and tried ANGLE Direct3D 11. That makes the fonts look good again. The problem is solved, but open GL has always worked fine for me. Is there anything I can do to make Open GL work properly again? I use windows10 64 bit, NVIDIA GTX 1060 with 3GB memory and an LG monitor (27UD69P). All drivers are up to date. Thanks! Здравствуйте, Александр, счастливого 2020 года, сейчас или, если хотите, через две недели. Сегодня я попробовал стелларий 0.19.3 и заметил, что сглаживание больше не работает. Я использую программу на мониторе 4K, с масштабированием шрифта Windows на 150%. Поэтому я вернулся к 0.19.2, но сглаживание не вернулось. Я снова установил 0.19.3 и попробовал ANGLE Direct3D 11. Это снова заставляет шрифты выглядеть хорошо. Проблема решена, но open GL всегда работал нормально для меня. Что я могу сделать, чтобы снова заставить Open GL работать должным образом? Я использую 64-разрядную версию Windows10, NVIDIA GTX 1060 с 3 ГБ памяти и монитором LG (27UD69P). Все драйверы обновлены. Благодарность!

That's wonderful, Achim! (and it makes me think - I have to complete a sketch from 30 December, but that is so last year)

Hi I looked but could not find any way to do what you want. This may be because all the data is NASA imagery, and NASA traditionally puts North on top in all published images. Who knows, the Quickmap team of Arizona State University might be willing to add a South up option in the next update of the website. Have you tried Quickmap's 3d globe? See here, it gets very 3D even on a normal screen. At least the SVS Moon has a South up version. Here's a screenshot of that...

Hi Dan, welcome. You joined the right forum! First thing to do is download the free program Stellarium from https://stellarium.org. That's a great tool.

Thanks Geoff.

Hi Paul, welcome.

Oh, that's bad. I hope the telescope itself is still OK. About the 4SE mount, I hope it's big enough for the 6SE to point straight up. The 6SE is 406 mm long and weighs 3.6 kg. The 4SE is 343 mm long and weighs 2.7 kg. The 5SE (330 mm long, 3.2 kg) and uses the same mount as the 4SE. The 4/5SE mount has a load capacity of 4.54 kg.

An extension tube will give you an upside down view (rotated over 180°). If the tube is too long you can no longer focus on infinity. The one you link to would most likely work just fine. In combination with a diagonal, an extension tube can be used for close range focusing. I use one to turn my scopes into long distance microscopes. There are 45° prism erecting prisms, which bring you halfway to straight through. The image quality suffers somewhat from them, which you may not notice at low magnifications. Straight through porro and roof prism assemblies are used in binoculars. I don't know if these are also made for telescopes. Again, the light path through them might get too long to reach focus at infinity, but if you focuser has plenty inward travel you are probably OK. If not, use a Barlow instead. A Barlow moves the focal plane of the telescope out. The tube you link to looks a lot like a Barlow with the lens removed. If you have a longish Barlow you can experiment a bit, with and without the lens.

Hi Denny, welcome. There's also an Orion version. Both are toy scopes, but they work and you can actually see craters on the Moon with them. More for kids I'd say, but better than nothing at all.

A lovely image! Warm and wonderful colours - great choice of palette.

That's wonderful, Neno. Very good!

This is also interesting: the NASA SVS Moon maps for every hour of every day in 2020 Enter a date and hour and click on the preview. This will download an image to your download folder. All the images combined make this video. (You may have to switch on the 4K by hand)

For children up to 6, I think 4x22 might be best. This is a Libra/Kasai model. In expensive and easy to use. (mind that the pupil distance is too narrow for quite a few adults)

Quickmap. There are many overlays, including one for nomenclature. Detail is down to 0.5 meters per pixel. Also try the 3D globe from the menu. This is a boulder on top of the central peak of Tycho: It's here:

It looks like this one: https://www.alibaba.com/product-detail/1-25-NO-ND96-0-3_1867510713.html?spm=a2700.7724838.0.0.23625c1dLIzIqn, made by Ningbo Barride Optics, Zhejiang, China.

Amazing. It has a coated lens. Dirt coated. I hope you'll have fun cleaning it and that the thing will give you some good views of the Moon.

Great! Nice music too. Thank you.

Congratulations Mark. These binoculars have a good reputation. I found this review for you: https://www.feathersoptics.co.uk/reviewSapphireED.php

I think the glue used to cement lens elements is of the type that hardens when exposed to ultraviolet light. That allows for time to position the elements before fixing them.

Oh Pepper, that is amazing!

Thank you Dave, for sharing your impressions. You are no doubt right! Most diagonals perform equally well. There's good reason to expect why this is the case. Suppose your old diagonal has 95% reflection and is otherwise good. You will see no perceptible gain from moving to a 99% diagonal. The gain will be 2.5 x log(99/95) = 0.045 magnitudes. You'll not notice that. Mirror flatness isn't all that important either. The light of each part of the view reflects off only a fraction of the mirror. Here is the light of one star reflecting of a diagonal that is far from flat: undulated diagonal surface In practice, if a mirror is 1/10th wave overall, it is 1/40th wave effectively when it comes to reflecting the light cone of a star. Even reflecting the light cone of a planet involves only a minor portion of the mirror, though it will be larger than that of a star and some minor image degradation may result from this. Nothing much to notice here either. What matters more than extreme reflectivity or extreme flatness is the roughness of the diagonal. The smoother, the less scatter. You will notice scattered light as halos around bright stars and planets. Microscopic scratches from cleaning are a source of roughness on mirrors. I bought my first replacement diagonal to take the place of an old aluminium enhanced (overcoated) Televue diagonal. Twenty years of cleaning had taken its toll on its surface. There was a small dull spot to the side. I got a dielectric one because that can withstand casual cleaning without getting scratched. It's wonderful for that reason! It will not turn rough over time an although theoretically a dielectric mirror starts off with a tiny bit more scatter than an especially smooth overcoated aluminium one, in the long run a dielectric mirror is a better choice. (That's a personal opinion, I know, but star diagonals do require regular cleaning and I want cleaning to be fast and easy without worry.) When I got a Nexstar 6SE, I replaced it's diagonal as soon as I could. It suffered from an enormous amount of scatter. Very poor polishing on that one! Flatness was okay. The dielectric replacement was an enormous improvement!

It's like a family portrait with everyone gathered in the same frame like this. Thanks Adrian, for a lovely image.

I'd go for the Morpheus 17.5 because that's an epic eyepiece which one needs to have anyway (because it is so engaging). It has a nice wide field with good eye relief, a well behaved exit pupil and great contrast and sharpness. It's an immersive and comfortable eyepiece. You'll certainly use it a lot.