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Ships and Stars

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Everything posted by Ships and Stars

  1. Hi all, I'm very much a visual observer but half-heartedly tried stacking some images the other night of M51 with shots taken using a 20" Stargate dob with GOTO and tracking. Also M97, M108 and tried a little around Markarian's Chain but those only have about 10 x 13" subs, no bias or flats. Results are erm...not great, but sort of a record shot. These are my first test shots with stacking and only M51 has many subs (115 13" subs for c.25 min integration under 20.3 SQM skies). No bias or flats. Just images+20 darks. Processing in DeepSkyStacker and just editing TIFF in LR 5.8, no editing in DSS. Using an unmodded Nikon D810 at ISO 3200. My main concern at the moment is obviously focus and coma. I didn't use a coma corrector, have the ES HR CC but my nikon adaptor doesn't fit in the end well. However, I'd like to remove the 2" eyepiece holder and attach camera directly to CC. Therefore wondering if: 1.) a coma corrector would make a big difference, and has anyone used the ES HR CC for photography? I need to remove the 2" EP holder and attach camera directly to CC tube. 2.) is there a better way to achieve focus? No focus mask for 20" dobs, so trying to use live view magnified to achieve best focus, but clearly not spot on. Wondering as well if diffraction spikes are blurring as the stars turn, since it's alt-az. I have collimated scope as best as I can, but can perhaps squeeze a bit better collimation out. I'll no doubt have more questions! Thanks in advance. Note - mods feel free to move if in wrong subforum.
  2. Yes it's driven, I tried your suggestion earlier this year and started using an 8mm plossl - this definitely helped tighten things up. I'll only use the up and right keys when centering on a star as per the synscan manual, but never thought to check targets slewing in that same direction if I follow you correctly. Interesting point!
  3. I've been surprised how it will maintain tracking and alignment in high winds though. January and February were really breezy here, don't think I had a calm night with the 20" except from home (under a lot of LP).
  4. Generally it lands at least in the outer third of the FOV with a 21E or 20mm APM. I'd have to look up how many degrees fov that gives. When it's off, it's consistently off though! By this I mean sometimes it lands right on something and I think great, but then slews a few degrees away and settles. I'm thinking when it does this it's needing some backlash elimination, but it hasn't happened much lately. I do have a lot of weight added to the base, would like to lose 500-750g there. Overall it's decent, but not pinpoint by any means. It will get you pretty close though. I've been able to find a lot of planetary nebulae, etc fairly easily without knowing what size or how bright they are. It's the really faint galaxies and nebula like the Cocoon that makes me second guess if I'm really right there or not, but suppose that's the nature of some of these objects?
  5. Thanks, all of this makes sense above. I suppose you could have a highly accurate encoder, but the overall system is only as strong as the weakest link(s), so a few small wobbles here and there with a leg flexing or a base settling into the ground can add up I suppose. It stands to reason a three star align would resolve or reduce error effectively, but not sure why manufacturers (that I'm aware of) don't offer it? Presumably it wouldn't be difficult to add a third alignment point, so perhaps it's a case of diminishing returns? I do note there are some tricks in the back of the synscan manual I've yet to try, that could be something to do this summer when the stars are ou, but too bright for most DSOs.
  6. Thanks very much for that, a goldmine of information there. It will be a little while, but I will keep everyone posted. I don't know on that one Gerry, I've heard others comment here or on CN a rough level will suffice for the synscan, but I like to get it as close as possible assuming it does indeed have an effect on pointing accuracy. Good point!
  7. The JB Weld was my cheap and cheerful solution once I discovered regular 1.25" EPs wouldn't fit... The Helios Apollo 15x70s are built like a tank and optically very good once you get them set up, with a few caveats. Each eyepiece focuses individually, so I'd lean against them if using them for terrestrial as they are quite heavy (2.6kg I think) and trying to hold them with one hand while rotating individual EP to get sharp focus with the other hand is, well, a workout. I much prefer a central focus wheel. You would definitely want these on a tripod or at least a monopod, especially if 10x50s were shaky. Being inclined as I am towards aperture fever, I'd probably go for the 22x85mm Helios instead as both really want a tripod anyway. THere is also the Helios Lightquest line which is newer and apparently even better optically, but no filter threads. Still, I'm happy with the 15x70s, but might see if anyone out there wants to swap+money for some 22x85s since there isn't much between them and my 12x70 Celestrons. My answer was probably clear as mud, haha! The Helios are excellent binoculars and well regarded across the board I think. Photo of the Helios/Celestron Cometrons side by side.... PS the Cometrons are not well regarded, but I think they are excellent and by far the most comfortable/widest FOV binoculars I've used with glasses. Plus they were ยฃ27!
  8. Yes the Swaro and Leica stuff (and Fujinon) is just flat out expensive but very nice I'm sure. I'd go for binoculars with a tripod bracket if you don't go the IS route - most decent binoculars should have them and a standard tripod should give decent stability for the smaller bins. Finding binoculars with filter threads is a little trickier - the Helios Apollo line have them, along with some offerings from Astroshop.eu, I think some of the Omegons have threaded filter receptacles or even flip in filter holders (Omegon Brightsky). Off topic a bit here, but I even used JB weld to attach filter threads to my Quantum eyepieces by cutting down some planetary filters. It came out ok actually.
  9. PS I don't think you can go wrong with Pentax binoculars from what I've read, I came really close to buying the 20x60 Pentax before the Helios 15x70s popped up for a good price.
  10. Since it is generally late in the evening and only earlier this year that I really started using the binoculars after observing sessions, Andromeda was behind the house but I've seen it a few times under LP and it was pretty decent but the LP dampened things down quite a bit. I'm hoping my 40x EPs in the big 100mm binoculars will let me take in the brighter galaxies with relative ease - another aspect you mention are the larger nebulae like SH2-264 and especially Barnard's Loop which I'm hoping the 20/40x100s will reveal with filters, but afraid I haven't logged the time in with them yet under dark skies! I do recall California Nebula was really nice with the 15x70s and OIII/UHC filter combo under 21.6+ skies, so the 100mm binoculars should work well. I am trying to find out how much of the larger nebulae I can see with the 100mm with filters, but it will likely be September again before I get a decent crack at it! There are a lot of very knowledgeable binocular enthusiasts here, especially author Steve Tomkin, who runs the excellent BinocularSky website and newsletter and owners who can tell you about IS binoculars and the probability of observing galaxies and nebulae with them. I did have some interesting views with the 15x70s/filters and definitely want to explore this more next observing season, especially from dark skies where the rewards are greater.
  11. I love my binoculars, I've 12x50 Bushnells (an old gift from my sister), 12x70 Cometrons (1.4kg best eye relief for eyeglasses/full FOV, light but still have tripod mount), 15x70 Helios (c.2.6kg I think, very heavy but well built!) with filter attachments which are great for large nebulae, and they also do well with star clusters under dark skies, and finally the 20/40x100mm Quantum 5.1s which I've only used for ship spotting so far, but appear promising. I'm in the process of making a fork mount for these, 7.2kg! Part of the logic for the Quantums was to use any 1.25" EP but these are the old version and only take the supplied 20x and 40x EPs, but for the price I couldn't pass them up. They should be excellent for large nebulae and galaxies with OIII/UHC/Hb filters when I finally get the mount sorted. Part of the allure with binoculars is being able to scan the sky quickly with both eyes - ideally without a tripod. Once you get into tripod territory, this advantage begins to diminish as you mention, as small scopes like the H130 can offer a lot more mag for less money and have a 'tripod' built in. I finish every observing session off with the 15x70s, kind of a ritual, but I don't use a tripod - I'll rest my elbows or the bins themselves on the roof of my car or wall, etc or just hold them. The drawbacks are a fixed magnification which in my experience is of course very low compared to what I'm used to with my dobs, but the upside is they are great for a quick scan when the weather is too unpredictable to set up a scope and can be used for terrestrial wildlife, birds, (wolves!) etc. Another upside is glorious binocular vision and the ability to freely roam around very large patches of the night sky in relative freedom unless you are looking at big obsy binoculars, but with the right mount, these can offer good mobility as well. All just depends on taste I suppose. The Canon IS should be pretty good from what I've read without a tripod of any sort, but for astro use, filter threads are a must-have for me. I came across the Starchair 3000/Fujinon 40x150 ED binocular combination below if money is no object ๐Ÿ‘
  12. If you want to observe nebulae and galaxies, I'd go for a second hand 10" or even 12" dobsonian, IMHO nothing will beat the amount of aperture and light gathering for the price. A 12" dob will have around 5.5 times the light gathering ability of a 130mm reflector and over seven times vs a 114mm reflector. In other words, you will see a lot more objects, full stop. I set my 12" up in two trips, first the base then the tube. I can easily set up in well under ten minutes. PS these will also do planetary very well if you buy a decent make with a good mirror. Lunar with binoviewers will knock your socks off! Check weight and dimensions if that's a factor, but the 12" is fairly easy to move around and packs a lot of punch. A 10" would be a great option as well. ๐Ÿ‘
  13. Ah that's brilliant, thanks very much! I'm hoping to get one more crack at galaxies before we lose total darkness. The pointing accuracy with your setup sounds very good, the synscan isn't bad, but I need to do some fine tuning in backlash. The 300p however would greatly benefit from a good push-tp to system. Fairly warm here again today, but rest of week looking so-so. Thanks again!
  14. Thanks very much. Lots of good information here. That is indeed excellent customer service all the way from Australia! The pointing accuracy adjustments are a big one for me as I often wonder if I'm actually in the right place for faint objects and especially galaxies unless it's an obvious one. It's hitting a balmy 17C here today in Scotland, must make the most of summer ๐Ÿคฃ
  15. Thank you omo and Stu! I'm very intrigued by this, if it can pinpoint galaxies then that's exactly what I'm looking for. The Synscan on the 500p can be excellent 'if' aligned and balanced, but if it's a little off at the beginning, this has a substantial knock on effect. The 300p with Nexus would be a brilliant mid-range scope, I'll contact AstroDevices and see what they say. Thanks again ๐Ÿ‘
  16. The size of that scope is just mind-blowing. I love the old grandfather-type pendulum clock mounted on the pier. The 37.5ton height-adjustable floor to reach the EP is another nice touch...
  17. Hi all, I'm intrigued by the Nexus DSC system but don't know anything about mounting it or what system I'd need. Wifi not a must-have, unless it cleans up the interface and does away with a control pad. Cost is the main issue. I was wondering if it was faster to align and more accurate in people's experience than the Synscan system on SW dobsonians? Primarily if I was able to increase accuracy once aligned on an object by pressing a button for a 'secondary' realign to correct for any initial error? I have a non-GOTO 300p flextube and was wondering if it could be easily converted to push to, and roughly what I would need? Just the Nexus DSC unit, or a whole load of brackets, gears, cables etc plus the DSC unit? Edit - if I make up azimuth markings for my dob base and get a digital inclinometer, I could almost just as easily replicate Nexus DSC for a tiny fraction of the cost, yes? I'd just get real-time coordinates off Stellarium, etc. Thanks for any thoughts!
  18. I do like the look of the ES dob, but I also have the 300p Flextube and love it alongside the 20" 500p, so the bar is pretty high for the 300p I suppose. It is very fast to set up and the truss rods can be locked in a shorter preset position to use binoviewers at native magnification without a glass path corrector. The base is fairly big for what it is, but certainly stable and can be easily carried with one hand while I use the other to open and close doors on the way outside. Speaking of which, it just fits through my narrow doors at home. I think I set it up before in under 4 minutes without racing. The collapsible tube makes it a lot more manageable to move around and transport in a car and store. I have a black foam camping mat that I was going to make a dewshield, but haven't bothered yet as it's never dewed up, even the secondary has stayed clear. Someone had a trick to put the foam tube inside the trusses, rather than around the outside, and it looks even tidier than the astrozap dewshield which is pretty expensive for what it is I think. The azimuth bearings are very smooth and the four nylon (or some sort of plastic) altitude bearings, although rudimentary-looking, work smoothly as well and the scope has 'dob knobs' to adjust altitude easily. It's a breeze to move around and point if you want to hop around the night sky quickly. The more weight you put in the focuser, e.g. a coma corrector and 100deg EP, the easier it seems to adjust altitude with a gentle nudge. It does have the single-speed focuser but it doesn't bother me because it snaps to focus quickly and I rarely finding myself hunting back and forth for fine focus. Having said this, I wouldn't be opposed to installing a dual-speed in the future. I do like the look of the mirror box on the ES model and how it nests together for storage/transport. You would need a full-length dew-cover for the ES as well. Finally, I suppose the key is optical quality. I've used mine up to 333x on Venus and find myself using the 9mm 100deg APM at 167x everytime I have used it lately. It gives some very pleasing, sharp views. The ES would be interesting in a way because I don't think a lot of people have them, if that counts for anything. It does look the business and looks well thought out. Meanwhile, the SW flextube base is fairly well-made, but the pressboard/chipboard MDF might need a coat of clear lacquer to prevent moisture from getting to it over the years - I have clear epoxy resin for boat building I was going to seal it with but so far it still looks new. The Nexus DSC looks interesting - I wonder if that can be fitted to a flextube? I don't think you can go too far wrong with either of them! ๐Ÿ‘
  19. Love the dob! I have a telrad on mine but have to mount it around the tube. A Rigel has a much smaller footprint, so considering going that route. Dig the raci dustcover as well! A really nice scope you have there๐Ÿ‘
  20. A lot (or at least some) of the American astro stuff is still imperial I think, as are various bits and bobs around our house. Some of the smaller fasteners might be BA as well.
  21. Ooooh, that's very nice. That would be a really useful size. My list is growing, haha. Number one for me, I seriously need a better workspace. Thanks John! Nice to see others making their own items. ๐Ÿ‘
  22. Thank you Tooth Doctor! I just ordered a set. Indeed Peter, I'm playing around a bit now with metal working and fabrication to test the waters, but if I can find a workshop locally to rent then I'll look at getting a proper TIG AC/DC pulse welder and perhaps a plasma cutter. A metal lathe or CNC mill would be spectacular. I worked for awhile for a firm in Slough fabricating industrial components, so not under any huge illusions regarding costs and complexity. Dreaming perhaps today, but plenty of time for that at the moment ๐Ÿ‘
  23. Thanks all, I went with this 110pc set like Dave has (glad to hear they work ok!), it was only around ยฃ50 from ebay with shipping and has various fine, standard and coarse metric tap/dies up to sizes up to M18x1.5. I'll probably never use the larger ones except perhaps for automotive on my ageing fleet of MOT failures ๐Ÿคฃ If I break any, I'll replace them with higher quality individual ones as I go. Stu - the first thing I do to determine what I need is to use a thread pitch gauge and digital caliper (pictured below) to determine what size screw/bolt and what thread pitch I'm dealing with, then hunt for the right tap/die. In this case, for the price, I just went for the whole enchilada as they say and bought a big set to avoid not having the right size in the middle of a project. My last set of tap and dies many, many years ago was a fraction of this size and easily twice the price. Amazing what you can buy online these days.
  24. That looks top quality! I was looking at drill presses from Machine Mart, etc. May I ask where you found your countersink drill to get that nice bevel? I could only find one or two online so far but haven't spent a great deal of time chasing one up (no drill press yet!) I've only ever welded mild steel with my MIG, but want to try stainless and aluminium. It's supposed to be able to do these as well, but TIG seems to be the way to go for stainless and aluminium. Great work there!
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