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AndyWB

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Posts posted by AndyWB


  1. Vaguely remembering my struggles with alt-az as a teenager EQ mounts seem a godsend to me!

    How on earth do you star-hop around with an alt-az when you have to cross large areas with only scattered nondescript stars? With the EQ mount I can easily follow the grid lines of the chart up and across.

    With a star chart and a low power eyepiece! It sounds flippant, but it works. I will admit I did concede and get a RACI, which does make star hopping with the dob somewhat easier (for following the chart). My Equinox 80 has such a wide field of view that it is it's own finder.

    Following grid-lines sounds so weird!

    • Like 1

  2. I agree with Olly - Equatorial mounts only make sense to me for photography. I'd go further, and more controversial, though - I wouldn't go for a comAlt-Az mount either. To me, it means worrying about electricity, and that's just another thing to go wrong. Unless you're fortunate enough to live somewhere really dark, you're bound to want to transport your scope to the middle of nowhere sometime.

    But I accept that there are arguments for computer control.


  3. Was the focusser actually moving? Check that the focus lock was off - otherwise the focusser knobs go round, but focus doesn't change...  It's a screw knob on the bottom of the crayford.

    The 10" should split the trapezium with ease. With mine, which is nothing special, I've seen the E and F stars of the Trapezium too.


  4. Nights which appear to have high haze and not great transparency often turn out to be excellent for planetary seeing. Conversely the very clearest nights can be quite unstable, perhaps because the earth is cooling more quickly. These nights are great for DSO observing at low to medium powers.

    Yup, that hits the nail on the head. My best planetary views have been through a high haze that I almost didn't go out due to.

    The only forecasting things that I've found are:

    • High pressure is good (less cloudy)
    • Jet stream is bad (poor seeing)

    Other than that, I use a weather forecasting stone.

    • Like 3

  5. I'd say 'good warm clothes' should be the place to start. In a few months I'll be wearing the same stuff I would mountaineering, if that gives any idea. Sitting still out all night gets cold.

    Charts of some form are a very good bet, along with a dim red torch, to avoid ruining your dark adaption.

    A collimation tool of some sort is a good call, though I find my 250px holds collimation very well - but you'll want to check that all your mirrors are aligned. Collimation is a bit of a learning curve, but isn't too hard after the first few times - particularly for visual astronomy, which doesn't need to be as precise.

    And I always recommend something like a Rigel Quickfinder or Telrad Finder to help make finding things easier.

    Why exactly needs a scope to 'cool down' ?

    If it's warmer that the environment you'll get thermal currents in the air in the scope. When looking through the scope this appears as though the thing you're looking at is moving in and out of focus. When a scope has cooled this stabilises (usually. Sometimes the same effect can be seen due to disturbances high in the atmosphere.)

    Oh, and I find my 250px to be very good. It's a good big aperture, so has good resolution, but is small enough to fit in my car so I can take it somewhere dark.

    • Like 1

  6.  And are the £15ish moon filters good enough or just disappointing?

    To be honest, I'd wait until you've looked at the moon with a higher power eyepiece first. More magnification dims the image; you might find it seems okay without one. I never really bother with one; I just crank up the magnification.

    The Williams Optics 6mm is a good one - I compared one of those against the Vixen SLV - the Vixen was a little sharper, I felt, but with a narrower field of view, and more expensive too. 

    • Like 1

  7. My understanding is that the ES 68 eyepieces are better corrected for use in fast scopes than the Baader Hyperions. Having used the latter with F/6 scopes I could certainly see some field edge distortions. Hyperions are great in slower scopes though.

    Yeah, I found the Hyperion range (Or at least, 5, 10, 17 and 24mm) poor in my f/4.7 dob, but really lovely in an f/6 refractor. My 28mm Maxvision shows a little distortion towards the edge - but not much, and it doesn't bother me. I think the ES ones are the same optics? It's a bit confusing - there were Maxvision, and ES, and now I see ES Maxvision branded ones...

    • Like 1

  8. Short version: just bought big fancy telescope with unimpressive stock eyepieces, please tell me what to spend £150-£200 on to make space more awesome.

    Okay, first, I'm going to assume that, being in Sweden, you already have an extremely warm jacket, good hat, scarf, etc.. If not, get warm weather gear first!
    Okay, next step 2 - do you have a Telrad, Rigel, or Red Dot Finder? These are zero magnification finders - like your finder scope, but just a window with a projected dot or rings on it. I find one makes 'getting in the right area' much, much easier. I'd strongly recommend one, and most 10" dob pilots seem to use that and the finder scope.
    Next - Dave is right, collimation tool. My 10" holds collimation very well, but it's good to be able to check. I've also found that the secondary's on some new scopes aren't well aligned under the focusser, and a cheshire can help with that.
    Right, now eyepieces. I tend to agree with you; my most used eyepiece is probably my lowest power (a 28mm Maxvision). This is in part because once I've got close with the finders, I'll normally use the Maxvision to find what I'm looking for.
    For planetary, I would tend to use a 6mm Vixen SLV (crisp, but only 50 degrees field of view) giving x200, or an 8mm BST (cheaper, wider fov, not as crisp) for x150). It depends on conditions - sometimes the atmosphere is too unstable (poor 'seeing') for the 6mm. I'd rarely try a 5mm, but I think a smaller sharper image is better.
    So, what to get? Well, I like my 28mm Maxvision, and it offers a wider true field of view, but for £69 the 24mm would be a good bet. It won't show you much more actual sky, but it will look much bigger when you're looking into it. Then I'd placate the husband by trying to find something in the 6-8mm range. Just be aware, not every night is up to the 6mm. And once you've got those, try to fill in the sizes in between as and when able.
    post-28380-0-22131800-1443781083.png
    (Yes, that's a Skywatcher Dob, but it's almost exactly the same spec as the orion)

  9. I have suspected that I've seen it in my 250px - but only as a faintly brighter region while moving the scope. As mentioned, it's large, so I found I kind of needed to 'run the scope over it' to spot that the background would get a smidgen brighter, and then dimmer again. If you were just looking at the one field of view, I doubt you'd notice.

    And even then, it might've been averted imagination. It's a tough one.

    And I think John is right - I think really dark skies are likely to be the key.

    • Like 2

  10. Thanks Paul, Would it be worth getting a filter do they make a great deal of difference..?

    Yeah, you can't use a filter for moonlight (or galaxies) - but for emission and planetary nebulae, it can help. Things like the Swan Nebula, Orion Nebula, North America Nebula and Veil Nebula can really benefit from them. However, the biggest improvement is clear, dark skies.

    I wouldn't rush for filters. But Paul is right - OIII and then UHC. 

    • Like 1

  11. Hi Andy do they work well with a Barlow. Just thinking if I buy one then use a Barlow with it I could cover low and medium mag thanks Ryan

    Sent from my D6503 using Tapatalk

    Well, I don't really use barlows, and I wouldn't want to HAVE to use one with a particular eyepiece. I'd skip them, to be honest, in the 250px. (The only reason I've even got the Hyperions for the Equinox 80 is that I won them. If I was kitting out the scope myself, I'd look at the Maxvisions or ES 68s.) 

    And for high power, I also use a Vixen SLV (though the 6mm) for x200. Lovely eyepiece.

    • Like 1

  12. Sorry, bit late, but +1 for the 28mm Maxvision, and I absolutely wouldn't go for the 24mm Hyperion in the f4.7 scope. I've tried them both in my 250px, and the Maxvision is vastly, vastly better. They hyperions (at 5, 10, 17 and 24mm) all showed distortion across a lot of the field of view. (The maxvisions show a little, near the edge, but it's much less and not so disturbing)

    I wonder, Gazabone might have a corrector in?

    • Like 2

  13. Right, I've been using my Equinox 80 as my grab and go lately, but I'm getting really annoyed with the difference between between the 10 and 5mm Hyperions I'm using, and the 28mm Maxvision. They're massively different focus - like other ends of the focusser travel. And I keep forgetting to transfer the 28mm Maxvision to the right case...

    Anyway, does anyone have any thoughts of a reasonably parfocal 2" eyepiece for low power - preferably somewhere in the 30-32mm range? (And not absurdly expensive.)


  14. Thanks guys.Its been a while since i collimated a dob and wondered what the current best method is?

    That seems to be a bit of a discussion. Depends what you mean by best, I guess. I use a Cheshire - as Paul says, nowt to go wrong, and can do the whole thing. Lasers are popular (good at night), and I know chaps who swear by the 'barlowed laser' collimation. I'm sure that there are more accurate, though.

    I'd start with a Cheshire.

    And neither my 250px solid tube, or my little heritage flextube need much collimation. But then the heritage does have a small, light mirror.


  15. People sometimes just put red plastic over their amazingly bright head torch and almost blind you.  Not great when you're at  a really dark site.

    Yeah, that's why I've a couple - one for seeing the floor, and one for reading charts. I've gone to great lengths to dim them both (buying black and red nail polish got me some looks). The other classic is using a head torch - and then looking at someone, illuminating them.

    • Like 1

  16. I'll see you there too!

    If you can, I'd advise just taking everything you need out of the car in the first place. I just unpack mine, ditch it in the bottom near the road (where there are some streetlights that the council won't shield) and don't really touch it all weekend. The other annoying thing is the way that many cars flash their lights when they're opened/closed with a key fob, hence my plan of just emptying the car.

    My essentials:

    • Tony's advice is good - pack food for the weekend (though I now just get breakfast from the cafe down the road, and only worry about lunch/dinner/snacks)
    • Scope cover - I can't be bothered packing after every night
    • Warm clothes. You'd be surprised how cold you'll get at 0200 in dewy Cwmdu
    • Dim red torch.
    • Comfy seat for socialising from.
    • Beer
    • Thinking cap for quiz
    • Money for more beer at quiz
    • Like 2

  17. I first spotted this with a 5" scope under very, very clear skies, and after a hour or so without any light (not even dim red torches) at all. It was fantastic, and it's still the best view I've had (better than my 10" scope). 

    However, it's so big it's quite easy to look 'through' and not realise you're seeing it. 

    I'd say clear, dark skies and plenty of dark adaption are key. Also, as Moonshane says, the gulf of mexico is the easiest bit, especially near the panama isthmus.

    • Like 1

  18. Is a Cheshire much easier to use?

    I find a Cheshire easier to use in daylight, and it can also be used as a sight-tube, for positioning the secondary. It's my main collimation tool.

    A laser is handy in the dark - but I find it's difficult to get repeatable results with mine. It's very sensitive to it's position in the focusser. I've tried the barlowed laser technique - and I'm just not sure about that, though that's mainly 'cos I'm not sure I trust the laser.

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