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Stratis

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About Stratis

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  1. Hi there, That is really nice work given you're using an ST80. My first bit of advice is to make sure your focus is dead-on and locked-down. Even if it looks ok on the screen, it probably isn't. The difference between in- and out- of focus can be 1/16th of a turn on the wheel I would advise you to buy a cheap Bahtinov mask for your scope, and use that to achieve focus. It is surprisingly easy and very accurate. That will improve all your images from then on. Other than that... it's hard to know which technique will work best with the GPCAM, single-shot or video stacking. I've heard of people installing cooling mods on the outside of their GPCAMs to reduce the noise in the images, usually with old CPU heatsinks etc.
  2. Hi all, After months of back injury, busted ribs and cloud, I finally got to use the CEM60 in anger These are taken with a QSI 583wsg, shot through a 115mm T-S triplet apochromat, and I continue to be amazed by how well this scope controls false colour. Didn't get as much data as I'd hoped for as houses kept getting in the way, but these are decent enough I think LRGB, 10 x 600sec exposures HaRGB, 17 x 180sec exposures total. There are some slightly eggy stars here and there, I still haven't got my flattener spacing right. Can anyone offer any advice on LRGB processing software? I'm using AstroArt but trying to look at alternatives.
  3. Nobody has any idea? Is it literally impossible to do this with available parts?
  4. So I have a quandry. I have a suite of good finders and guidescopes of varying types and sizes, all of them in the Synta-style wedge format foot. As fate would have it however, I have ended up with two of my main lightweight scopes being little William Optics refractors, a Megrez 72 and an 80mm triplet imager. These of course, have the William Optics-style shoe installed. I'd like to know if anyone has cracked the problem of using Synta bases on WO shoes. I can imagine the shape of the adapter in my head, just a question if anyone has made one before... Thanks
  5. As a GT-81 owner I can recommend it, but you must budget for a field flattener; the GT-81 does have a curved field. I have no experience with the Esprit but they produce highly detailed and sharp images competitive with the better imaging refractors on the market, so I doubt you'd go far wrong. I also echo the recommendation for the Explore Scientific 80mm triplet; it is a neat and lightweight platform with good CA control and lesser field curvature than the GT-81, although I'd still recommend a generic flattener. In general I think you are on the right lines!
  6. Well, alright. Personally I think a small frac is always going to be easier for the beginner than a medium-sized newt, for the reasons you mention. Narrow FoV, wind and balance issues, collimation, all that jazz. Yes, I advise you to go for a small refractor, they are excellent and vanishingly easy to use. Your setup time is halved, your troubleshooting time is near-zero because there's only about three screws on the whole thing. If it's an 80ED or bust, then yeah, go for it but make sure you have the 0.85x r/c, as far as I'm concerned that is an essential item. You will get good data out of it at a low price. Buuuuut.... If I can persuade you to look into f/6 scopes, I think you will have an easier road of it. With a standard 0.8x R/C unit (also essential...you DO need one) that goes way down to f/5 or thereabouts. You will be able to create lovely images with the SkyWatcher so please don't feel like you can't buy it or that it'll let you down; it won't. But I also know that if you can start your imaging train with that extra f stop under your belt, it will make a lot of headaches go away. Also consider that lower f/ratio almost always means a shorter focal length, translating into an even wider field of view. I tend to image between 500 and 700mm and the difference at the lower end is remarkable, although objects do tend to get a bit small. Either way you'll be better off than mosaics with a large wind-catching tube.... that way be dragons
  7. Actually I don't advise going for the 70ED. A large number of optics are sourced from Taiwan and China, which in itself is no bad thing; these companies (Long Perng, Kunming Optics) are the reason we can buy a sharp, unadorned apochromat for less than the price of Sky TV. The optics are generally good, but not equally so. The 70mm series, in my experience, is a bit of a black sheep in the small apo market. They're nice for travel scopes, but honestly they suffer from an unusually great amount of chromatic aberration, specifically a green/purple halo around stars. The 72mm however, for some reason known only to whichever optician came up with the formula, fairs a lot better. Altair produce the 72ED-R which I heartily recommend, as it contains the same lens group as the William Optics Megrez 72 you see in my signature. It's the lightest scope I can image with, and it's at a nice quick f/6. One thing; it's a doublet, so you will still see some residual halos around stars. Nothing much to worry about really, at small apertures CA is usually well controlled, but it won't stand up to a triplet on colour correction. I advise you to search on Astrobin for the scopes you're looking for, to see images made with them (make sure you're looking at the *imaging* scope, a lot of people with huge telescopes use a 72mm as a guidescope!). The 80ED would serve you well, but as Ive said in another thread, I am not a fan of its focal ratio; f/7.5 for me is just way too slow.
  8. Oh absolutely... I do my photography between f/1.8 and f/4 and even going up to f/4 bothers me when I shoot raw and see all that extra noise. Even with a cooled CCD, every f/stop you advance is not so much robbing signal as it is adding noise. Your final images will always be that much muddier, requiring that much more processing, more subs, more time to bring them to the standard they could have been already in half the time. There are plenty of imagers able to overcome this and process truly spectacular vistas out of data captured at f/8 and above, but they walk a very difficult road, and generally have observatories
  9. I thought of having a go at that, but if you look at the response curve, only the very highest blue frequencies are permitted by the red filter, so simply adding blue to red won't work, as that would effectively make *all* blue stars purple rather than those with a bias towards the upper blue/ultraviolet range. I guess that's the problem they're trying to address, a standard B filter treats all 'blue' light the same, and thus cannot actually make that jump to violet that the rods and cones in the human eye actually show us.
  10. I'm going to offer what may be a controversial piece of advice for an imager looking for a beginning refractor, but its one that I've come to over many nights of amateurish fumbling with imaging setups; Do not bother trying to image above f/7 native I know, I know, thousands of people do it well and someone's almost certainly doing it right now, but honestly, focal ratio is the single most irritating and immovable obstacle to satisfying imaging as a beginner, at least in my case. I see the value of RC and Cassegraine setups at extreme focal lengths for really high resolution, but very rarely is the beginner in possession of the craft and experience to handle that kind of setup. A beginner needs simplicity, and a setup that aids the learning process rather than impeding it with a panoply of possible failure modes. With a fast scope of f/6 or lower, you will accumulate data like nobody's business. One single night of imaging will yield twice as much data, or twice as many targets, as a similar experience at f/8. As a beginner, particularly considering a refractor (I own far too many refractors, I love em ), I advise you to look into faster optics. William Optics do some lovely ED scopes at f/6, as do Altair Astro, with reducer/flatteners available to get you down closer to f/5 even. This will allow you to pull more light and detail out of your target faster, and all else being equal that is always a good thing. As others have said, the 80ED is a cracking scope and gives wonderful views, but it has always struck me as a refined 'classic refractor' concept for visual work rather than an imaging platform.
  11. Hi chaps, While waiting for the seemingly-interminable bad weather stretch to clear up, I've spent some time looking into my imaging setup. I'm using a QSI 583 mono CCD, so rely on LRGB for my colour data. The filter set I currently use is the Astrodon E-series, which is alleged to be colour-balanced specifically towards the 8300 sensor, but I ended up doing a lot more narrowband than broadband and haven't had much opportunity to test that. I've recently run across a somewhat esoteric filter set from IDAS, which comes with a most unusual feature; the red filter actually permits some very low-wavelength blue light along with the red: IDAS claim that this gives hot stars a 'violet' colour by boosting the red channel on a hot blue-white star... My question then, is this a good thing or not? On the one hand my scientific brain feels this is somehow 'corrupting' my colour data... but on the other hand, it is true that the human visual system perceives the upper blue frequencies as purple, not the pure blue that a standard B filter would give you. I'd appreciate the insight of my elders on this one, if anyone has any experience with them
  12. I paid under £400 for mine, which is less than their original RRP so I feel quite fortunate. I've seen them offered at £450 and £500, including one bloke who had a full set hinting at a £600 price for the 30/40 that I doubt I would go for given how close it is to 21mm Ethos territory! I have to agree with John's characterisation of the XW30, it really does give an impression of restrained excellence. I'll be selling about five 20-40mm eyepieces from my collection now that I have such a remarkable piece.
  13. Got this out under the stars briefly.... amazing. The view was very similar to the Zeiss surgical eyepieces I reviewed recently, but much wider and more engaging (if a touch softer). This is the best mid/wide eyepiece I've ever used; I will now have to begin selling off all the lesser EPs I bought to cover the 30mm range
  14. ...I have it! Perfect condition, still in the original box This is one massive strike off my bucket list, been searching for over two years for one of these little beauties!
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