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Alfian

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Everything posted by Alfian

  1. There's an article here that might help. I've not tried this out on my 6/8 SE mount but I'm assuming the accessory output socket in a car would work, with a long enough lead. Our Vauxhall its rated at 12v with max of 120, so about 10 amps. https://www.nexstarsite.com/OddsNEnds/PowerSources.htm
  2. I have the Avant mount which I bought with the little 114/500 reflector. It works just fine with the 114 and also my 102 Mak and a 90 f5.5 refractor. The lightweight tripod and extension are just that, lightweight, just as suitable as a photo' mount. It would be possible to put the avant on a heavier bettet tripod but the lightweight setup idea then starts to slip. The Avant is marketed with a 130p f5 reflector. In my opinion this pushing it too much but I'll admit to being one who doesn't tolerate well a scope taking several seconds to settle every time its nudged.
  3. An interesting one. The AZ4 with steel legged tripod, which is definitely worth having over the aluminium item) is quite a substantial mount. It does not have slomo controls so you have to nudge it or steer it manually. I found with a telescope that has some length or bulk to it (4" F9 refractor/ 6" f5 reflector) this is easy and not a problem. Lighter scopes need a more delicate touch. This is down to the AZ4s friction bearings suffering a lttle bit of "stiction". Its not a problem as such and with a minor strip down, cleaning and regreasing with a quality teflon based grease can be noteably improved. All in all though the az4s a good mount. I've not used the AZ5 mount but it has had some good reviews and it has slomo controls. I do have another mount (Avant) with the same tripod and extension. It is much lighter than the AZ4 and I would not want to use it with the scopes mentioned above. That said it would probably work fine with the shorter 4"startravel. There is always the possibilty of upgrading to the steel legged tripod with the 3/8ths fitting if you want something better. The az5 tripod still makes a useful photo tripod. If you plan at some time to get a larger scope like a 150p then I'd go for the az4. If you are happy to stay with the Startravel or smaller scopes then I'd go with az5.
  4. I like refractors and a 90mm f10 (900mm) achromat makes for a very capable scope for anyone let alone a young starter. Pretty much bullet proof and easy on eyepieces too. My concern here is that they often come with inadequate mounts and usefully need a decent altaz mount (az4?) or an eq3/2 if an EQ mount is preferred. This bumps the budget up. I've had a Heritage 130p mini dob and although the mount is very simple and the helical focuser very basic the whole thing works surprisingly well. Optically it turns in a very respectable performance and for this it seems to have gained a small army of fans! With respect to "limited collimation" I have a little 114mm f4.3 reflector with a fixed primary and just the secondary adjustable - not what would have thought an ideal thing, however in practice it not a problem and the 'scope holds its collimation well and like the Heritage 130p it performs much better than I for one would have expected. Life is full of surprises! The upshot of this is that with a limited budget, and especially with a nod to how portable and easily storable the scope is I'd also recommend the Heritage 130p or equivalent. Any spare cash needs to go on a couple of plossl type eyepieces.
  5. Heck, thats sad news. The unfortunate thing is that the 100r focuser and diagonal is something of a bespoke item and not easily replaced, mind you, Tals are solidly engineered and maybe if you know someone with engineering skills they can get it corrected.
  6. Its a nice problem ti have but there are so many flavours (distros) of linux to choose from now, its only by playing with a few that you get one that suits all your needs and is reliably fully functional. For me these last few years has been MX linux but I've had a play with Zorin recently and although it has a slightly bare bones look to it, its actually pretty good.
  7. Well done that man! The 130EQ focuser illustrated doesn't get any better than that. I suspect the missing item is the one in the bottom red square. If the thread on the focuser tube is a male T2 then its an easy fix but from memory I think the thread is coarser than that and may be a different size altogether. When I had mine, I contemplated changing the focuser but on the Celestron, with its cosmetic plastic trim, its not quite that simple. Not an impossible job but I decided not to bother and upgraded to another 'scope. In terms of spare parts Astroboot are useful but at the moment are closed for refurbishment. A bit of a long shot but a wanted ad' on this forum might come up with something. good luck.
  8. A useful idea to work with is exit pupil size, that is the aperture divided by magnification. Your 250p (1200) with say a 20mm EP will give 60x and this will give just over a 4mm exit pupil. An eyepiece yielding 300x will give 0.83mm exit pupil. I find with my slightly aging eyes that anything much below 0.5mm and I run into problems with seeing floaters but by this time the image is notiecably dimming. The point here is that pushing magnification to the max is not always a good thing and in terms of seeing detail although object image size is smaller, often less is more so to speak. That said for a scope like yours with a sizeable aperture pushing magnification to 300x (+) is more likely to be limited by conditions and in practice will be significantly less. The good news is that with all that aperture DSO hunting should be rewarding.
  9. The 130EQ is 1.25" (only) focuser. Casting my mind back to when I had a 130EQ I think the part you might be referring to the eyepiece holder that screws onto the focuser tube. If that is so all you will have at the moment is the end male threaded section. Is that so?
  10. Yes, I've found that in SW Scotland there is little point in looking at forecasts beyond a couple of days. Even very locally it can be pouring with rain in one place and just a few miles down the road its dry all day. Depending on where the prevailing weather is coming from its often funneled through the hills leaving the coast with better conditions, ie you get a local micro climate. I hope very much it stays good for you all.
  11. Do you think that possibly the Tals might have gone back to the iron age? They have that rugged rustic feel to them. No flourite though!
  12. Indeed. I'm currently on the opposite side of the Cree estuary, rain has abated to that fine stuff thats blowing hard in the wind. Sun is trying to break through and there's a rainbow. Forecast for the week though is not so bad apart from lower temperatures
  13. Maybe the earliest form of "Clearoutside"? That feeling of being lost in wonder is something that strikes at soul level and add to that the dimension how it links us directly to our ancestors, its a powerful humanity definining emotional experience. There's always the possibilty I could be talking twaddle but thats how I see it!
  14. From memories of my 130EQ days the 20mm eyepiece is an erecting eyepiece provided for terrestrial use. Why Celestron would choose to do this is a mystety to me. Why would anyone buy a130EQ for terrestrial purposes? Marketing I guess. The erecting eyepiece design compromises it for astronomical use. Although it means spending more money, buying plossl eyepieces improves things noticeably. I would also echo the comments above about atmospheric conditions which make a big difference. Also, viewing planets when they are low down, which effectively exagerates poor conditions further, isn't going to yield good views.
  15. Great write up, looks like its going to be a scope with a high "grin factor"!
  16. Is the Tal100r new to you or are these abberations a new occurence? The Tal100r does give a kind of very pale yellow cast on images but for an achromat it, well mine anyway, performs very well. The Tal100r objective lens cell is collimatable. I have a Baader semi-apo filter and I've only tried it in a fairly limited way in my ST120. I had no expectation that it would work any kind of wonder on the CA but first impressions are that stars look a little "tighter" more pleasing to the eye but thats a long way from being a scientific analysis! Looking forward to trying it in the Tal and my Vixen achro.
  17. Hi and welcome to SGL. I have the 1145p although I'll admit I bought it mainly for the SW Avant mount. That said the little 114 scope surprised me with how good it was. This is quite a fast scope at f4.4 and spot on collimation of the mirrors is essential but I've found that it holds its collimation well. I wouldn't assume the collimation is out, but its worth checking. I found that a simple collimation cap is all thats needed. The light weight and short focal length of the 114 makes it ultra portable but a draw back of that f4.4 focal ratio means that it really benefits from better quality well corrected more expensive eyepieces. I use a 20mm explore scientific 68 degree eyepiece for good wide field views. For luna and planetary work (in just a 500mm scope) you will need a much smaller focal length eyepiece and a good barlow lens is helpful. I have a 10mm Baader BCO which with its matching 2.25× barlow gives decent lunar views and the equatorial cloud belts on Jupiter are easily visible along with its 4 larger moons. It needs to be said though that planetary work is not really this scopes forte. Pushing the magnification too much doesn't achieve anything other than making an indistinct image more blurry and darker! As said though, within its limitations its works very well. I can't vouch for your goto but if you can get it properly setup there's no reason it shouldn't serve you well. In terms of improving the scope I've found flocking the inside of the top of the tube opposite the focuser and blackening the edges of the secondary gives a little more contrast and I've also stripped down the focuser, cleaned the old sticky grease out and regreased it. I've also given it larger focuser knobs. This has made the focuser a little smoother and easier to use. Overall just small improvements but worthwhile. Once you've familiarised yourself with the scope you can decide how far you want to go with it. Enjoy your new scope.
  18. A problem with the Celestron 130, because the native finder is built in (and not very good) it doesn't have the kind of shoe that most optical finders use. When I had the 130eq I found the easiest solution was to fit a Rigel Quickfinder which is a reticule type red dot finder. Its base sticks to the tube using the (very) sticky pads privided. Its lightweight and a bit plasticky but it works very nicely. Although I have long parted with the 130eq the Rigel is still going strong years on.
  19. I can pretty much guess the answer to this one but I'll float it out anyway. For quite some time I've contemplated acquiring a 6" F8 reflector, but having moved house in the last year and now having that feeling of landed and sorted I'm here again looking at the same question. My home observing station has changed to one of a small enclosed courtyard garden and whilst this restricts views and there is some encroaching stray light from neighbours, when skies are clear its good Bortle 3. In addition we have a nice substantial dry summer house which I can store my 'scope so its just a matter of lifting it out 3 yards or so. Wonderful! Mount wise I have a decent heavy duty tripod, extension pillar and Giro mount, (which i use with the Tal100r) for it to go on. Orginaly it was simply going to be the SW 150PL but then I got looking at the Bresser NT150L (150/1200) being somewhat seduced by its functionally good looking hex focuser. The C/O is larger than the 150PL but that, should I wish, can be easily remedied. Since my days with my F7.3 Tal 1 I've liked the idea of a long F8 larger aperture scope, so what's stopping me? Well apart from a recent tempting courtship with a C6 I keep looking at the Bresser 8" F6 Dob. Since my time with an 150mm F5 reflector I have felt I must, compared to many folk, be a bit sensitive to coma, perhaps in the way that some people are more sensitive than other to CA. On paper the F8 scope is better by far in this respect but the extra aperture and the fact that an 8" Dob for me is now a really practical proposition its very tempting. As said I'm guessing the "aperture wins" voices will shout loudly. Perhaps the question here is, in real practical (rather than theoretical) observational terms how noticeable would coma be comparatively between the F6 150 and the F8 200. As a secondary question does the 8" Bresser Dob need a riser base to bring the eyepiece to more practical level or is observing from an adjustable height stool work sufficiently well? I've not used a Dob of this size before. Thanks.
  20. A good drawing David, glad the 12.5mm is earning its keep.
  21. I've been running a 64bit Linux distro (MX Linux) for the last couple of years, no problem.
  22. The OO 'scope/focuser is a bargain as it is and imo it would be criminal to split it. A great scope for somebody, maybe a good dob project.
  23. Achromatic refractors have a simpler lens configuration that means that not all wave lengths are brought to focus at the same point which in practice means that on brighter objects like the moon you will often get a yellow or purple fringe to the bright edge of the image. That is, however, not the whole story. A short focal length achromat (F5 or so) the light path to the eye is at a wider angle (than it would be at say F10) and produces a greater level of chromatic aberration producing more colour. For something like a 102/F10 achromat the CA may not be too much of an issue, although some people find it more distracting than others. Increasing the focal length even longer the light cone narrows to the point where CA becomes even less of an issue but of course this makes for quite a long 'scope which in tern brings its own challenges. I have an old Russian made Tal100r achromat 100/1000 (F10) which does show some CA (which i can live with) but is otherwise very sharp and a very useful scope indeed. As you can gather seeing achromats as scopes that "have distortions" and by implication not desirable, is not always quite how it is and many astronomers have spent many happy and useful years with an achromat! The alternative in refractor terms is to go for an "apochomatic" scope where the lenses are of a type,quality and configuration to bring light wave lengths to a single focused point. Such quality costs much more money but they are very very nice! Looking back and doing a leap where I can learn from my mistakes without the cost is difficult as that learning process has been important. One of the big lessons was that the quality of the mount is almost, maybe as, as important as the scope itself. A wobbly marginal mount leads to nothing but frustration. This is where Dobsonians score. You get a stable mount and more aperture for your money, so to start again yes I'd go for a Dob , and although the 8" makes a lot of sense, I'd go for the 6" F8 Dob. At F8 its easy on eyepieces, easy to collimate, potentially will give a wider field of view and a makes for a good cost effective all rounder. This is where I's start but I suspect I would still finish up having a long-ish refractor too. Where ever we start, as sure as eggs are eggs, experience, circumstance and developing preferences will lead us on to other things - better, bigger, smaller, more refined, more expensive .....
  24. This reminds a little of my experience with my Tal100r although in analysis it probably something completely different. I had a SW100ED and very nice it was too with beautifully sharp tight images, luna spectacularly so. I parted with the SW 100ED and got the Tal 100r (not a story for now). Yes, the Tal has CA where the 100ED didn't, but its not sufficiently distracting to spoil things, however what immediately stood out was the Tals ability handle magnification. With the 100ED I would inch things up to the point where resolution started to go, whereas the Tal just seems to be up there (200x) more easily without any particular strain on the eyes. (eye) Clearly this isn't a side by side, same seeing conditions comparison, but in terms of lasting impressions over time this is how I see it. I don't have the scientific optical wherewithal to be able to explain what that amounts to in terms of the Tals optics but I'm not complaining.
  25. I don't think there is any "winning" with astronomical telescopes. There will always be positives, negatives and what will suit one person may not suit another. I think its better to choose a telescope, put that in a search on SGL and read what people say about it, then decide whether you think whether it will suit you. If it doesn't move on to the next. Its sometimes good to get peoples view on two closely matched scope eg Bresser vs Skywatcher 8" Dobs, but to have a long list of scopes that differ so much is, I think, a fruitless line of enquiry, and asking people, in effect, to decide for you, isn't going to work.
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