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Nightspore

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Everything posted by Nightspore

  1. Suitably emboldened by successfully upgrading the PPA version of Cartes du Ciel 4.2.1 on Linux I decided to have another stab at installing the PPA Stellarium. I ran Stellarium for over a decade on Microsoft Windows. I thought it was a wonderful program and the fact that it was freeware made it even better. Several years ago the Stellarium development team changed its rendering engine. For some reason this affected the Windows BIOS clock by pushing it forwards a minute every time Stellarium was opened. Although, unlike Unix, Windows BIOS clocks are notoriously inaccurate anyway. Eventually I uninstalled Stellarium from Windows but carried on using it on Ubuntu. I now only run Unix operating systems (Ubuntu, Chrome OS, macOS). Since upgrading to Ubuntu 20.04 LTS I had been running the Snap version of Stellarium 0.21.0. Snap packages contain a lot of necessary libraries and dependencies and can be updated without adding Personal Package Archives (PPA’s). I can understand why Canonical introduced Snaps but they have disadvantages as well as advantages. One of the prime disadvantages is that you have to rely on the Snap developer to update a specific Snap package. The developer of the Stellarium Snap has left it at 0.21.0. Stellarium is now at version 0.21.2 and I finally decided to install the PPA and the latest version directly from the Terminal (command line). It seems fine so far and I’m pretty happy with it.
  2. As far as I know there are only two companies that manufacture traditional Abbe orthoscopics. Both are Japanese. Ohi ortho's are sold under a variety of brand names including Astro Hutech and Kokusai. Below: rare volcano top 9mm Circle T (Tani) orthoscopic made with Ohi optics. The other is Takahashi. Takahashi ortho's actually have a 44 degree AFOV although it's impossible to have greater than 42 degrees with a traditional Abbe. I suspect the extra 2 degrees, achieved with a slightly bigger field stop, are a marketing gimmick and to aid target acquisition. It does improve overall viewing ergonomics. Tak' ortho's have superior contrast to the Ohi, although they do have slightly less transmission IMO. They are probably the best ortho's money can buy. Orthoscopics as a whole are unrivalled in contrast and overall acuity. Although they have a smaller overall field compared to Plossls, they have slightly longer eye relief. I use orthoscopics a lot for lunar and planetary observing. Their simplicity and transmission coupled with outstanding contrast makes them basically unbeatable. The Baader 'Classic Orthoscopics' are their take on an old Zeiss design. They still have a 42 degree AFOV but that's been increased to around 50 degrees by using a larger field stop. This extra field is just to aid target acquisition and will display some lateral astigmatism outside of 42 degrees. The 32mm BCO is actually a Plossl. The 10mm BCO is an excellent eyepiece. Orthoscopics are a bit specialist and an old design. In recent years they have been making a bit of a comeback. In my opinion they can't be beaten for high planetary magnifications. They're £59 new. Baader Classic Orthoscopics PDF
  3. I'm pretty sure all of these were manufactured by JOC (Jinghua Optics and Electronics Co., LTD) who are the parent firm of Bresser and ES. They've always had a good reputation. A lot of eyepieces are made in the same factories, regardless of what's written on the housing.
  4. There's a whole back story about the Maxvision series but I can't really remember it lol. I'm pretty sure they are basically the same as the ES 68 degree series. I think Meade changed their suppliers at one stage and the series stopped being produced. I never bought the 20mm 68 degree Maxvision or the ES as I've owned a 19mm Panoptic for years. The Meade/ES series are very good though. Have you used the 8.8mm yet? I actually prefer it to the 9mm Nagler!
  5. I'm pretty sure a lot of the older Meades have the same light train as the ES equivalents and were made by JOC. I think the Maxvision were made originally for Meade by JOC and were the same as the 68 degree ES series with but different housings. I nearly bought a Maxvision once. They had a good reputation. JOC is good glass though.
  6. The Snap package is actually quite stable. My guess is that the PPA version has issues with some dependencies.
  7. Bear in mind these things are huge. Alright for a 20" Dob maybe. I have a Telrad but I've never used it. I bought it for my 102mm SkyMax. It's longer than the scope! Personally I think they're a bit overrated. A Rigel OTOH is small, compact, efficient and a marvel of late 70's Bakelite technology. The base has to be glued onto the OTA however. So you have to do this right the first time lol. Plus the reticule can pulse with variable speed! Parallax can be a slight issue, but I find they work well.
  8. It's often easier to rotate the eyepiece to the right if the tripod is set up high. This ensures that you don't accidentally thread the diagonal *nosepiece loose. Usually the slo mo is also easier to get to when seated to the right. Although that just may be me as I'm partially paralysed on my right side. Unless you have a rotating focuser. Most of my refractors have rotating focusers, several are aftermarket. With the cat's I usually have them low and sit directly behind. The main difference is that the image will be rotated if the diagonal is rotated. *A big reason I use an Everbrite on my 72ED. It's one piece of cast aluminium so the nose won't unthread.
  9. Why not just get a 4.5mm eyepiece? Either way, the AFOV of the eyepiece will be important tracking at high speed with a Dobson mount.
  10. OK, I've been checking Amazon and some may not have a stand. There's always the Altair RDF. Or you can buy the stands separately from TS Optics. It would still be cheaper to buy the reflex sight from Amazon and the stand from TS than everything from TS. The stands have Synta compatible feet and will fit any Weaver mount.
  11. I think they all come like this. I have an 'Astromania' still in the box identical to the TS in the picture above. They all have Weaver (NATO) mounts anyway. The stands may differ, but as far as I can recall the stand is included.
  12. Looks good. Eventually you might want to get a better reflex sight. The plastic ones do the job but can get unreliable over time. The 'Aomekie' on the left is basically identical to the TS Optics on the right and cost less than half the price. They probably came out of the same factory.
  13. They're probably both good. The GSO looks like it has the better focuser as it is dual speed. I have an f/6 150mm GSO Newtonian. The focuser is only single speed but it's smooth and accurate. The optics are good as well. One caveat with a Dob' mount though, they're not ideal for lunar/planetary tracking at high magnifications as Right Ascension will move the target very quickly in the field of view. So the wider angle the eyepiece you use the better.
  14. You're welcome. It's mag 7.6 at the moment, although it may be visible in the early morning around December 5th ~ 11th.
  15. Cool pictures! This may be visible to the naked eye in early December.
  16. I forgot Cartes du Ciel. It runs on Windows and Unix platforms (shown on Ubuntu 20.04 LTS).
  17. If you have an Android device SkyPortal has a lot of info. Plus, it's free.
  18. Reversed Kellners are OK in slow scopes but the bundled 'giveaways' are usually just to get you started. This Japanese 'volcano top' Kellner (above) is quite good quality but in any scope faster than f/8 it will display lateral astigmatism. This is where stars near the field stop appear stretched out or look like tiny 'seagulls'. These 2" GSO reversed Kellners (above) will show a flock of seagulls in most of my refractors, although I can just about get away with it in my f/7.5 80ED (below). Kellners are often maligned but they are simple (three element) with good transmission. They can produce the famous 'floating in space' effect where images in the eyepiece appear almost three dimensional. I've seen this with open clusters at low magnifications. Most large Celestron SCT's are usually bundled with 40mm and 13mm Plossls (my 235mm Celestron SCT and 40mm Plossl above). It might be worth getting a 40mm Plossl as well. They have a limited field but are the only way to get a decent exit pupil on a big cat' without using a focal reducer. It would give your scope 37.5x with a 4mm exit pupil. This would enable you to use some UHC or OIII filters to help see faint nebulae. I'm guessing the skies in Crete are better than mine in Worcestershire lol.
  19. You're welcome. I'm not sure who make these Plossls but they're as good as the Barsta-made ones that were usually marketed as Orion, Celestron and Sky-Watcher. Plus the 'Astro Essentials' have chromed brass barrels, which are an improvement on the aluminium barrels IMO. I have the 17mm and the only difference I can see with the Barsta equivalent is that the field stop is fractionally smaller. Celestron are owned by Synta and Sky-Watcher is the Synta house name.
  20. Personally I doubt a Barlow will be necessary with a scope of 1500mm focal length. It's more likely that a focal reducer would be more useful. Introducing a *negative lens group into the light chain can sometimes cause issues on slow catadioptrics in my experience. If the Barlow and eyepiece aren't matched well it can cause glaring and/or ghosting effects. SCT's and MCT's are high power instruments with limited fields of view. They are not ideal rich field (low magnification/wide angle) scopes. Open clusters, many nebulae and large but dim deep sky objects don't require large magnifications as much as they need more light and therefore a greater exit pupil. Calculating exit pupils for SCT's is easy as you just divide the eyepiece focal length by 10. For lunar/planetary targets and maybe some DSO's (globular clusters, distant galaxies) a spread of between approximately 1.5mm, 1mm, 0.7mm and 0.5mm is probably a good start. Bearing in mind the human eye is not very efficient with exit pupils narrower than 0.5mm. High magnifications are also dependent on atmospheric seeing and overall transparency (humidity/cloud). Furthermore the target itself and its position in the sky has to be taken into consideration. On a good night the Moon, when high, can take up to 60x or 75x per inch of aperture without much loss of detail. The higher the target's altitude the less atmosphere there is to look through. Unfortunately, the planets are low in the northern hemisphere at the moment. Jupiter is notoriously difficult primarily as it is a high contrast target. Getting well defined views of a low Jupiter (even at transit) is not easy at very high magnifications. Even with a quality refractor. Refractors don't reflect light unlike reflecting telescopes and have no secondary obstructions. Therefore they will always have more visual acuity and contrast than reflecting scopes. So, my advice is just to buy better quality eyepieces than the ones bundled with your scope. I'd start off with two or three inexpensive Plossls (maybe 12.5mm, 10mm and 7.5mm) to begin with. Plossls have a 50 degree FOV with good acuity and contrast which is why they became popular with amateur astronomers to begin with. *A Barlow works by essentially artificially increasing the focal length.
  21. I tried the upgrade from the Terminal yesterday. Nothing happened. I booted up today and the Software Updater opened and installed 4.2.1. I feel like this now!
  22. I finally convinced CdC to upgrade (not the Snap) on Ubuntu 20.04 LTS. So far I'm impressed. The GUI has been updated. CdC doesn't upgrade frequently and when it does it's usually pretty stable and actually improved.
  23. Depends what you are observing. A 5mm eyepiece will give 300x, but achieving that regularly on anything other than the Moon would probably be difficult. A zoom eyepiece might be a good idea to experiment with. The Orion 7~21mm impressed me for its retail price. Also, bear in mind a 6" catadioptric can take up to 90 mins to an hour at least to acclimatise or cool down outside. Maybe longer. SCT's have a microclimate inside the OTA and need to reach a thermal equilibrium where the outside and inside temperatures are the same. Until they are, warm air currents inside the tube will prohibit achieving a sharp image.
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