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Everything posted by AndyWB

  1. Well... Stellarium is available for Macs - http://www.stellarium.org/en_GB/ <-- click on the apple at the top... That said, I prefer Sky Safari on my Macbook. I think it might've been on offer when I bought it - I think it was about £10 - and I know it's hard to beat free, but it's more reliable, and much easier to use.
  2. Hmm. So my car won't power a hairdryer if the engine is off, and the sidelights can't be turned off. Hmm.

    1. AndyWB


      I may need to consider a proper dew heater...

    2. scarp15


      I use a 12V 7ah battery and can connect the 12V hairdryer via an adapter (cigarette socket for hairdryer and clips for battery).

    3. AndyWB


      Hmm. Yes, I'm wondering; if I started building a leisure battery type thing, I'd be tempted to just get a secondary heater...

    4. Show next comments  21 more
  3. I used to kayak with a chap who worked for the RAF in the north of Scotland who, as he put it, "identified clouds as 'friendly'" as his day job. He told me that there were things that appeared to exist on radar, and had unusual performance characteristics - but he didn't feel the need to invoke little green men. Mostly, he was suspicious of our American friends. And I don't mind being like bacteria to our alien overlords, so long as it's "minute, invisible, bacteria"...
  4. That's a fair point, but for a 8" or a 10" Skywatcher, I don't think there's a lot in it. I believe they use the same base (which is the heavy bit), and the optical tubes are the same length. The 10" is a bit more bulky, but not that much. But the point generally is a good one - either could be a pain if stairs/disability/etc. are involved.
  5. This one comes up quite frequently, and I usually seem to end up suggesting "Increase your magnification". It dims your image, which is normally a bad thing, but for the Moon can be useful.
  6. No, I get the same in my 250px; cap to see the clips, then Cheshire to align it all.
  7. Yeah, I can't see all 6 clips with my cheshire on my 250px. I have to use a little collimation cap - it seems to give a wider view. I'm going to go with option 3 - it's all fine, everything's probably central as the clips are all on the edge of what you can see, and the secondary is (I hope) central and round, and the Cheshire hopefully has everything aligned. Mine are like that - just on the edge of the field of view, but I can't get all 6 at once.
  8. Well, this did definitely move. Very slowly, but after the flare some sort of small satellite was still just visible, then it went brown and faded out, which I guess is it crossing into night. It must have been a satellite, but I've no idea which.
  9. They certainly were for me, and have come up on here a few times. When I first saw them I'd have described them as a UFO, but a quick question on here turned them confidently into an IFO, which is much less exciting. But if aliens ever visit, I would like to welcome our new overlords...
  10. I don't think it's daft. It didn't take you 6 months to realised that the tube wasn't round...
  11. So I was out tonight in West Berks, and at 1821 I happened to be looking west with my Mk I eyeballs when something flared. For a moment it became brighter than, well, anything star-like I've seen - brighter than Venus or Jupiter - before dimming just as quickly, though I could see a little spot of light that looked like a satellite drifting off. It was near Pi Herculis, just above the keystone. "Ooo" I thought, "I might just have seen my first Iridium flare". Heavens-Above does not show any Iridium flares at that time. None of the brighter satellites on it are in the right place at around that time either - and they didn't really feel bright enough. Are there other things up there that flare that brightly? I mean, it pretty much seared itself into my retina… and I'm really curious as to what it was!
  12. Approaching 2 years at this game, and I've 107 Messiers. I'm missing M83, M68, and M104 (which is an odd one to have missed). I seem to go ages, and then bag a load in a 'big night out'. I have been fairly assiduous about tracking them down, and 'seen' might overstate it. 'Found a faintly fuzzy patch in AV that turned out to be in the right place' might be more accurate.
  13. Mine is worse! I was struggling with collimation, until Shane had a look at it at the last SGL - and just centered the secondary under the focusser by eye. I'd been measuring the center of the tube, which wasn't working very well. As long at the secondary is in the right place, the rest doesn't matter.
  14. The Primary mirror is the EASY big. I find getting the secondary right is the hard part. The 6 screws should be 3 for adjusting it, and 3 as locking screws to hold the mirror in place once adjusted. I think. I'm not sure which is which, though. The screw in the middle of the second picture is the one that hold the secondary mirror on. Think of it as a stalk, with the other 3 pushing the back of the secondary mirror mount to change it's tilt. This image should give you an idea of the overall structure, though on yours the head of the allen screw in the middle would be on the left - it's the philips one in the picture above - and that way round makes more sense to me... But you get the idea about how it adjusts tilt. You can adjust the middle screw too, if you need to move the secondary towards or away from the primary mirror (to center it under the focusser) - but I'd loosen the other screws first, and make sure the scope is pointed down so that if you accidentally unscrew the secondary mount entirely it won't drop onto the primary mirror. Good choice on the Cheshire over the laser.
  15. Yeah, well I still wonder about that. I mean, mine shows a touch at the edges, but not so much that it bothers me (or even really notice), and only with certain eyepieces (I.e. the 28mm MaxVision. Lovely eyepiece, but my scope makes demands on it). I do wonder about if he got a duff mirror or something. On that note, I did recently get a chance to try each of the Hyperion 5, 10, 17 and 24 mm eyepieces in my f4.7 Skyliner 250px. Now THAT was coma. They were dreadful. All of them, and the 17mm was curiously worse. However, stick them in my f12 or so hydrogen-alpha scope - lovely views. So no, I'm not in a rush to use Hyperions at that speed. My experience with my 5" and 10" dobs is that the 10" still has much better resolution (for splitting doubles), but for DSOs there's a lot less in it, at home under LP. Somewhere dark, though, and the 10" is much better. I think Umadog's reasoning is on the money with this one. I've not tried the Delo's but this matches my experience pretty well. And I know they're narrow, but I do like my SLV a lot.
  16. I compared a 10" SCT with my 10". There wasn't anything in it, really, at the same magnification. I suspect that the author meant it was unsuitable because he doesn't like nudging - which is fair enough. Planetary is high power, so more nudging. Doesn't bother me, it might've bothered him. But you can get tracking/GOTO dobs, so you don't have to nudge - though that defeats part of the point of a dob in my mind - or you could put it on an Equatorial Platform, in which case it will happily track for an hour or so. (They ain't cheap, though).
  17. I went after 6 Trianguli the other night, and got distracted by Struve 239, which was just visible as a double at lot power. It had a cute orange colour to me. And yes, I did get Gamma Arietis too - it had a weirdly green looking primary to me! (I'm starting to doubt my colour perception!)
  18. From what I've read, Flextubes are pretty good, but perhaps more prone to dewing (due to the open tube), and a heavier (!) than the solid tubes. Personally, I won't bother with GOTO, but I'm a bit of a luddite. A good map 'll see ya proud, lad. Setup is the best bit about dobs. The setup process is set down, take off endcap (important), and look. Seriously, so much easier than EQ aligning or configuring a GOTO system. They sit on the floor, but the really dinky ones (not an 8" or larger!) can go on a table or box. I prefer to sit next to mine - I use a drummers stool, 'cos it has an adjustable height and is portable. They can be big beasts. I have a solid-tube 10" dob and the tube takes up the entire of the back seat of my car with exactly 2cm to spare. I believe the 8" is the same length (and a more forgiving focal ratio, so less demanding on the optics of your eyepieces). They're also fairly heavy (mostly the wooden base) - I'm not small, but I do tend to move mine in two pieces if it's going more than a few feet. I was glad I went and had a look at one first. Yes, the dimension usually given is the aperture - so an 8" reflector is 200mm. Refractors of a given aperture are normally regarded as outperforming reflectors of the same aperture, but they cost a lot more, and you don't often see them bigger than about 6". Reflectors offer more bang per buck, but with compromises. I got my 10" for occasional "big nights out" and star parties - my 5" sees a lot more use, but for shorter stretches, and in town. It's worth thinking about where and how you plan to use it, and to see one in the flesh first, if you can.
  19. Not very well, no. For long exposure photography, you'll want an EQ mount. The problem is something called field rotation: http://www.astronomyasylum.com/telescopemountstutorial.html You might be able to get a few shots of the moon or planets with dob, but proper photography needs an EQ. It is possible to mount an 200p dob tube onto an EQ mount, but be aware, it's pretty darn big; it'll need a big, strong mount or any wind will turn it into a sail. Astrophotography is more about the mount than the scope, which is why smaller refractors on big, stable EQ mounts tend to be more popular. From reading around here, I've come to conclude that it'd be better to have separate visual and photographic setups...
  20. 101 Objects? But what about the rest of the Messier catalogue? ;p
  21. I don't know, they all seemed enthusiastic enough to me in the last episode! That was one of the things that came over in the show - you felt like everyone - project, presenters, press, hell, probably cameraman too - was really excited! I remember that the Sky at Night used to be on at REALLY awkward times on BBC2 - either really late at night, or on a morning at the weekend, when I'd occasionally catch it when at school/university, depending on the level of hangover (too little, and I'd be doing something already. Too much, and I'd still be in bed). I actually think it has a much better slot now, though with iPlayer, such things matter less. And the think I liked about it (through the fog of last night's beer) was the science. You'd get some funny looking guy (the weird looking ones were all guys) describing mindblowing stuff on the other side of the universe. I was fascinated by that long, long before I even thought about looking up through a scope. It didn't need Brian Cox in the Namibian desert - the wonder was in your head, from some plain studio somewhere. Incredible. I'm not sure how much field based amateur astronomy content there is. They did do an episode from Astrocamp in Wales, but it's kind of dark, and how much film do you want of other people looking at the sky? I mean, it definitely needs a bit - if only to send the message "You can see this stuff too" - but I think there already is (last episode being an exception). And I'm not sure I'd want it to become just a sky-guide. Although reasonably inexperienced, I can spot a certain amount of repetition in the sky-guides. The one approach to a guide like that which might work would be a short guide focussing on a single object - say, something from the Messier or Caldwell catalog - and tie a little in a little science. I heard Pete Lawrence at a star party talking about Epsilon Aurigae and it's oddly long dim cycles, and that was fascinating. I could see it, and he was talking about the science, putting it in context. And I suppose there's the thought that over time, the Beeb could build up a little library of videos on iPlayer about 'stuff in the night sky'. Just a thought. Anyway, I thought the coverage of Rosetta was brilliant. Fascinating, exciting, and immediate. Bravo! I must confess, I've watched it twice. It might not be perfect, but I'm glad that S@N isn't another 'Celebrity come dine with me dancing on ice in the jungle' show.
  22. FWIW, there is an OU course about the constellation Orion coming up. I liked the Moons one, except for all the geology. I get why it's important, but there was a bit too much trying to identify unpronounceable minerals. I'm guessing the Orion one will lack that, and it's a fair bit shorter.
  23. Interesting... presumably one needs tracking mount and a long focal length to isolate a star and hold it there?
  24. I have a 130p and would happily recommend that over the Virtuoso. I just don't think you need tracking, and the 130p gathers quite a lot more light. That said, it is not good for photography. As others have said, really, you need an Equatorial mount, rather than a Dobsonian. The only exception that I've had a little luck with is the Moon, just taking afocal shots through the eyepiece. Even that's fiddly, and would get old pretty quickly. E.g. - an iPhone shot of the Moon... Edit: If I might recommend, start with visual only (which is much cheaper), and if you want to get into Astrophotography later, then save up and get a dedicated AP setup. They have quite different requirements anyway (Astrophotography is, I understand, more about the mount than anything else)
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