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Nightspore last won the day on June 30

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  1. That's not even half of them lol. Although your earlier statement that you'd prefer a 70mm refractor is a good choice. Refracting telescopes are quite different to catadioptric reflecting scopes like Maksutov Cassegrain or Schmidt Cassegrain types. Refractors have a sharper, more contrasted view generally. Astronomy isn't always about size of aperture and a 70mm refractor can be as effective as a 100mm reflector in many ways. The most inexpensive refractors are basically achromatic doublets. These can show some chromatic aberration (CA) however. My ST80 and ST102 are achromats. The CA can be seen as a light blue or purple haze around bright objects. Although it's often unnoticeable at lower magnifications on many deep sky objects or open clusters. Focal ratio is also a factor. Your Maksutov has a 'slow' focal ratio. This is good for high magnifications but also only has a relatively narrow field of view. A faster small achromat will have a wider field of view. To get higher magnifications you just have to use something like a Barlow lens. My 102mm achromat (above) was about 170 quid when I bought it. They are surprisingly good for the money. The green MoonLite focuser it now has was £360. It was worth it as this is a fairly portable but large scope for me. I've had two different after market focusers on it in the past. I never used it with the stock focuser as it didn't rotate. Short fast achromats can be very effective scopes for observing star fields and faint objects like nebulae. Achromats do suffer from CA though. A way around CA is to use a scope with Extra low Dispersion glass. Above and below show my 72ED DS Pro Evostar. A 72mm fast achromat with ED glass. It's incredibly versatile. This and my Altair 60 EDF are probably my most used scopes. Small fast refractors like this can be used for relatively high magnifications on lunar/planetary targets, yet also can be used at wide field low magnifications. Moreover, they are very portable and easy to set-up. A doublet refractor with ED glass ameliorates CA to some extent. There are also triplet and quadruplet refractors. These are heavier and much more expensive usually. A small ED doublet refractor can be an ideal compromise between weight, size and expenditure. The Altair 60 EDF above has really good Japanese Ohara ED glass. It's only 60mm but I've seen transits of some of Jupiter's moons with it. Even better; I can get a small refractor and the AZ5 into these bags. So it's definitely worth thinking about a short tube refractor.
  2. I have a 127mm SkyMax. To use mine while seated I'd rotate the diagonal to the right usually. Although the AZ5 mount can be lowered enough for me to use binoviewers. My 127mm Mak was bundled with the AZ5 although I usually use it for smaller refractors. I can either set the tripod low like in the above picture or raise it higher and rotate the diagonal. The Altair 60 EDF actually has a rotating collar to achieve this. I have an ST80 with an aftermarket rotating focuser especially for this as well. I'm partially paralysed on the right side of my body. So my right arm and hand have limited range and dexterity. Being able to rotate the diagonal safely with one hand is important to me. You might find something like the ST80 and a light alt-az tripod a lot easier to use. Above you can see my ST102 with a rotated aftermarket (Long Perng) focuser. That particular focuser is now on my 80ED DS Pro. I doubt there will be any in-focus problems with an extension tube on a 127mm Mak. It's worth pointing out that there are 45 degree diagonals as well. Many give a corrected image and are known as Amici prisms. Amici prisms can also be 90 degrees. Ignore any claims in this link. The SvBony 45 degree diagonal has a mirror and gives an upright but mirror reversed image.
  3. Are you using a telescope with a diagonal? It's possible to rotate the diagonal downwards. Most astronomy needs to be done while seated comfortably anyway. I'm physically disabled and often need to sit underneath a tripod with the diagonal rotated. Also, an extension tube can help lengthen the distance between eyepiece and diagonal. Not all extension tubes are 2". Some are 1.25". I don't know if this helps.
  4. I don't know who actually manufactures these aspherics. Some Chinese OEM no doubt lol. There were rumours Synta were going to bundle the 10 & 23mm with some of their scopes, although nothing ever came of it. The housings are plastic, although the aluminium barrels are well finished. One of the lens elements (most probably the eye lens) is a polymer material. I guess the aspheric shape is easier to mass produce as a polymer plastic. They've often been referred to as the first disposable eyepieces. Although mine have lasted a few years and the bino pair were last used on the most recent Mars opposition. They are also virtually indestructible and can be dropped and possibly drop-kicked without incurring any real damage. The 23mm is outstanding and virtually as sharp and contrasted as my 25mm Ohi orthoscopic. The 10mm is almost as good and pretty easy to merge with as a pair in a binoviewer. Avoid the 4mm though. It has serious lateral colour; almost certainly attributable to the additional Smyth lens in the barrel. The 10 & 23mm don't have the Smyth. It's been conjectured that the 4mm is only the 10mm with a barrel tele-negative lens. Either way, it's basically the 'turkey' of the set.
  5. These 10mm 'SvBony' aspherics are incredibly good for 14 quid. I use a pair for my bino. Although I've swapped the barrels for smoothies. You have to use these to realise how good the 10mm and 23mm plastic fantastics are. They have been sold as 'Vite' and Meade. The 4mm should be avoided; it's basically a DIY spectroscope lol.
  6. The Starbase O/PL’s were originally acquired for my 102mm Sky-Watcher SkyMax Maksutov Cassegrain. Its focal ratio of f/12.7 should ameliorate any aberration problems that were noticed in the faster scope. The initial rationale behind buying these eyepieces was that they were relatively light in weight, ergonomic (I like volcano tops), and had good build quality. The whole SkyMax grab and go kit needed to be light and portable and fit into a small holdall-type bag. Everything, including the diagonal and the 7-21mm zoom eyepiece, were chosen as much for weight as optical performance and quality. Technically the SkyMax should have a 2.1 light grasp ratio over my 72ED DS Pro. However, the catadioptric has an obstruction (Secondary or Gregory Spot) and the light is reflected as opposed to being refracted. As a consequence reflecting telescopes generally lack the contrast and acuity of refractors. Sir Patrick Moore once claimed that serious lunar observing starts with a 6” reflector or a 4” inch refractor. A 150mm reflector aperture is 1.5x larger than a 100mm refractor aperture. Using this ratio the 102mm Maksutov roughly equals a 68mm refractor. There is an old joke that 4” Mak’s are only good for looking at the Moon. They do have a good reputation for splitting double stars. I’ve owned the 102mm StarMax for a long time and tend to predominantly use it as a lunar grab and go scope. The 20mm Starbase gave me a nice view of Saturn and Jupiter at 65x. It was when I started using the 14mm it started getting interesting. Although I did notice the undercut snagging occasionally when swapping eyepieces. The three screws of the Baader helical compression ring can often be a little finicky with barrel undercuts. The 14mm O/PL gave a fairly sharp 92.8x. The seeing was above average, but not as good as the previous night. Jupiter’s GRS was just noticeable near the western limb and would be about central at transit (03:20). Ganymede, Callisto, and Io were close together on the western side of the planet with Europa on the opposite side. I could perceive colour in the moons and discern some Jovian surface detail. As the planet rotated the GRS became more easily visible. I decided it was time for the 9mm ‘Orthoscopic Plossl’. At 144x I lost a lot of acuity and furthermore there appeared to be quite noticeable ghosting. Jupiter is very bright at the moment though with a visual magnitude of -2.8. Inevitably I switched back to the 14mm and even the Orion zoom for a while. I still couldn’t manage much above 100x though. Saturn fared better with the 9mm but even then I didn’t think it was as sharp as it could have been. This was probably more to do with conditions than anything else. When Jupiter reached transit I still wasn’t satisfied with the 9mm although around an hour later I had a much sharper view at 144x with no ghosting. I think that 144x at an 0.7mm exit pupil was pushing the Mak’s optics a bit much. Undoubtedly further than they should have been in the conditions. I’m convinced it would have been much easier to get the same exit pupil with a refractor. By comparison the 72ED will reach 140x (0.5mm exit pupil) comparatively easily. To finish off I decided to split some early morning twilight doubles. These included Almach, Polaris, Sheliak, Struve 2470/74 and Epsilon Lyrae. In my experience Mak’s tend to make the first diffraction ring a bit brighter than refractors. This is possibly due to the influence of the Gregory Spot. Lastly I split the three components of Iota Cass beautifully at 216.6x with the 6mm O/PL (0.47mm exit pupil). I’d re-calibrated the Rigel finder earlier in the week. The ‘QuikFinder’ is notorious for parallax issues and I really had to concentrate to find Iota in the early dawn. It was worth the effort however. The 6mm and 14mm Starbase seem to be the most used of the four eyepieces. The 6mm is quite exceptional in many respects. I’m a bit ambivalent about comparisons between the Evostar and the StarMax. The Maksutov effectively has a limiting magnitude of 12.74 compared to the 11.99 of the smaller ED doublet. I can often reach around 140x with either of them for planetary observing. Although, at the end of the day, I personally prefer the better visual acuity and contrast of the smaller refractor. The 102mm aperture has a Dawes limit of 1.14 arc seconds in comparison to the 1.61 arc seconds of the 72mm. The question is does 0.47 of an arc second and 0.75 of magnitude really make that much of a difference? These are basically backyard telescopes small enough to be carried in a flight bag.
  7. I have the 15mm UltraFlat. It's similar in overall size to the 19mm Panoptic. I believe they're manufactured by KUO.
  8. Wednesday, July 21st, 01:00 BST. I could see Io and its shadow near the western limb at 01:00 BST. I was using the 72ED and 140x magnification (6mm Tak' ortho' plus TV 2x Barlow). Seeing was well above average although the low, bright, Moon caused some transparency issues. I observed for about 75 minutes and watched Io and its shadow slowly track across the surface. At 02:15 I could still see both Io and its shadow. Io was a light brown-yellow colour.
  9. Very nice. The Sky at Night Magazine rate it very highly. One size fits all lol. It is very similar to my 102mm Altair Starwave with a 714mm focal length (f/7). S-FPL51 has a good Abbe number. My 72ED DS Pro probably has a CDGM equivalent to FPL51. It is very well colour corrected. You can use your new Starwave Ascent on the Saturn opposition in thirteen days! Honestly; there isn't much you can't see with a good 4" ED doublet. At four kilo (same as my Starwave) it's a nice compromise between weight and aperture size. I was talking to Bill Paolini on Astronomy Connect a few years back and he's always maintained 4" is his favourite refractor aperture size as it is the best combination of portability with performance. He did some experiments with a 6" triplet and aperture masks of 5" and 4". He reckoned the performance differences between 4" and 5" were negligible compared to the 6". The 6" obviously showing the most detail. But he reckoned there wasn't a huge difference between the 4" and 5" and the 4" was the better compromise, especially with considerations of weight and overall convenience. And of course, Messier used a 4" refractor lol.
  10. There is an online web version. If you have an Android phone or tablet SkyPortal is basically a free version of SkySafari. I used it on a Chromebook and an Asus tablet for quite a while until I upgraded to SkySafari Pro. The freeware Celestron app is based on the same rendering engine as SkySafari and has a lot of the same functionality. It's well worth downloading if you have an Android device. The pictures above are SkyPortal on a tablet. The picture below is SkySafari 6 Pro on macOS. You can see how similar they are. Although I used Stellarium for over a decade I tend to plan most of my sessions in SkySafari nowadays.
  11. Around seven years ago Stellarium started to shag with the BIOS clock in Windows. The Stellarium developers had introduced a new rendering engine into it. Every time Stellarium was opened it would push the BIOS clock forward a minute. The Windows BIOS clock was notoriously inaccurate anyway and generally knackered in my opinion (like most of Mickey's software). Stellarium has always worked well on Unix-type platforms. Unfortunately Alex (Stellarium developer based in the Ukraine) hasn't managed to get Stellarium signed for Apple as I can't get it past Gatekeeper. He told me he was working on it. Although I can't get GIMP past it either. The Apple 'walled garden' is bloody impenetrable lol. I don't know about running Ubuntu in a virtual box. I just run it the old fashioned way on a Lenovo laptop. All Linux flavours can have hardware compatibility issues. So it's best to make sure the OEM hardware itself supports Linux. I doubt this would affect a virtual box though. I'm not an expert though lol. Oh yeah, if you're reading this Alex, pull your bloody finger out! ROTFL (just kidding Alex).
  12. Excellent pictures. I witnessed the transit in real time. The seeing was a good Antoniadi I in my opinion.
  13. How about Ganymede transits? On Sunday, July 18th at around 01:38 BST I could plainly see Ganymede off the Jovian western limb. Its shadow was well defined more or less in the centre of the equatorial belt. Although there were transparency issues the seeing was exceptional, at least Antoniadi I. I was using a Sky-Watcher Evostar 72ED DS Pro. I was initially observing with a TV Everbrite diagonal and a 4mm Takahashi orthoscopic for 105x. There was a Baader Neodymium filter in the diagonal nosepiece. The diagonal was rotated to the right of the fully extended AZ5 mount/tripod and I was seated comfortably looking up into the eyepiece. After only a few minutes I upped the magnification to 120x with a combination of a TV 2x Barlow and a 7mm KK Fujiyama orthoscopic. A few minutes after that I replaced the 7mm KK with a 6mm Tak' ortho for 140x. About an 0.5mm exit pupil. The detail was incredibly sharp and well defined with very rich colours and good colour separation. The GRS was a not easy to discern though as it was near the limb. The 72ED DS Pro unsurprisingly has an aperture of 72mm. The doublet 'flint' is an unknown extra-low dispersion glass, but very well colour corrected almost certainly has a good Abbe number. The 'crown' is Schott. The visual back is aftermarket with a compression ring. I had a Baader 2" - 1.25" adapter in it. All four Galilean moons were resolved into discs and I could perceive colour in some of them. I watched Ganymede approach the limb and eventually transit the planetary surface during a period of over an hour. I also witnessed its shadow approach the opposite limb and eventually disappear. When the shadow had completely gone I could still distinctly see Ganymede against the planetary surface. It appeared a grey - brown colour. The Evostar has only 12mm larger aperture than the Altair 60 EDF.
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