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About London_David

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  1. If it’s for Eea use then you want a faster scope (lower f ratio) so on the specs (I’ve not used it) the night owl will give you a better result. Images will be much faster to appear. On specs alone the order of appropriateness for eea on the cameras 533, 294, 183. The 533 is ahead of the other two because it has lower read noise and similar or higher qe. If you like the of the 533 and it’s in your budget, go with that. I’ve never used any flats in eea, it always seemed the point of eea to me was to be as quick and similar to live as possible. I do use darks sometimes because the software can integrate them on the fly. More pixels give you resolution, but you trade off resolution for light sensitivity. It’s like having an array of buckets lined up to measure rain. Lots of narrow buckets can tell you where the rain falls more accurately, but wider buckets will catch more rain - any single larger bucket is more likely to catch a single drop of rain. You could add up the water in the smaller buckets together to approximate the size of a wider bucket and in a perfect world you can get the same result - that’s what binning is. But it’s always a bit inaccurate - that’s what read noise is. Qe is how much water is lost when you try to count the amount of water in the bucket. The problem in astronomy is that there is very little rain (light) from the sources, so any water you loose can be significant. Mostly now, on the new cameras, smaller buckets are more effective because you can get resolution if you want it, and bin to get the sensitivity if you need it. This is especially if your buckets are providing empty resolution because on any given night your telescope or seeing may not be able to support more detail (magnification). Older camera designs were very bad at adding the buckets together and there would be lots of noise when it was done, hence why sometimes it’s better to have fewer, bigger buckets so there’s less adding up after the fact.
  2. There is a pretty big difference in real life. Overall the AZGTI is much more compact and I'd say can only take about 75% of the payload. For instance, the EQ3Pro carry's the 150PDS with ease, and while I have used the 150PDS on my AZGTI it's very wobbly and I wouldn't recommend it. It works for EAA but not visual at all. Put it this way: I once accidentally gave the 150DPS a nudge when on the AZGTI and it almost fell over. I got my AZGTI for travel. I can get an 80mm refractor, the AZGTI mount, a small computer, eyepieces, cameras and the tripod in a nike skateboard backpack and I take it on the plane in hand luggage. Its over the official weight but no-one ever checks because I can sling it over my shoulder and no-one is any the wiser. It would simply be impossible to do anything remotely like that with the EQ3. It's much bulkier heavier and more awkwardly shaped. The EQ3 Pro is old reliable tech - all mechanics no electronics, no built in power and it relies on the external handset. The AZGTI is much more modern based around wifi control with batteries and brains built in and using a wireless external app for control. For the first 18 months when I started I'd set up the EQ3 and the 150PDS in my bathroom and point it out the window... so it is small for a mount, but not nearly as small as the AZGIT. If size is your thing, I don't know of anything smaller and more portable than the AZGTI. The Avalon mounts are much better (and more beautiful) on size/payload ratio, but they're vastly more expensive. If you want to use the AZGTI in EQ mode you can, that may improve the stability, but I haven't tried it personally. I keep my 80mm or 100mm refractor on it most of the time and it's very happy with that. I think you might start to struggle with anything over 100mm on the AZGTI. Depending on the length of the tube my SW 100mm f11 is pretty much at the edge of where I'm comfortable with balance on the AZGTI. The weight isn't a problem, but the balance on a long scope is. 60-90mm is probably optimum size for it with OTAs about 40-80cm long. The tripod on the AZGTI is okay. It's not awful, but it's not great. I have several photo/film tripods and I prefer using those since they're much lighter easier to use and generally more stable. It never going to compete with Sachtler Flowtec legs, but then those are £2k. To be honest though, right now I have it sitting on the original tripod and it's been on the skywatcher tripod for months. I use it most nights like that since my other tripods are often needed for other things and I'd rather have it ready to go on okay legs than have to set it up with amazing ones. If you have a good tripod, save your money. If you want a good tripod you might use for other things, buy something else, if you want something that is good enough and relatively inexpensive, the tripod is fine.
  3. If it helps at all - the EQ3Pro is goto, as well as much lighter, smaller and cheaper than the EQ5. It's what I used to use with my 150PDS.
  4. Hahaha. Thanks. I currently use the one it came with but it’s not very good! Previously I used the sticks from a Manfrotto 501 video tripod. The AZGTI will fit into any regular tripod with a standard central 3/4” screw which is pretty handy. When travelling I take the carbon fiber legs from a photo tripod I have. Ultra light and pretty stable if you add some central weight.
  5. The first thing is… if you want to do EAA then you need a goto mount. It's not optional. You need your mount to be able to track the sky. There are ways around this, I suppose, but only if you know what your doing. Goto is by far the easiest and I think you’d be crazy not to budget that as a basic need otherwise I think you'll be frustrated. The AZGTI and the EQ5 are very different mounts. The AZGTI is goto to start with… The EQ5 is massive in comparison. If you are looking for a starter setup you should really go for the AZGTI. It’s a great all rounder even though it has a lower payload. Polar alignment is often made to be more mystical and difficult than it is. The thing is there are different levels of acceptable polar alignment. In fact, you can do it faster than an Alt Az alignment if you aren’t too worried about accuracy. And sometimes - for example in visual - you don’ need ultra accurate alignment. If you want to look at Jupiter, point it vaguely north and find Jupiter and set it to track and your done, just look through the scope. Of course, if you want to take 30 minute exposure pictures that’s different thing! To get really accurate polar alignment is incredibly difficult and time consuming. Most people only need rough polar alignment where you adjust the screws until you get Polaris in the right place in a viewfinder. It's relatively straightforward, though depending on your mount's design, it can be annoying. That said… if you’re hesitant about EQ, you probably should go for an Alt Az mount. Most people prefer that for simplicity anyway. I prefer EQ mounts but that's my personal preference and I think I'm in a minority. The main advantage of EQ for EAA is you can have longer exposures. But... for EAA using modern cameras like the ZWOs that doesn’t matter. The AZGTI will track ok enough for EAA on a sensitive camera (like the ones you mention). I con comfortably do 15 second exposures on my AZGTI which is enough for most stuff in my light polluted location. You can convert the AZGTI to EQ mode if you want to experiment with polar alignment. However, I've been using it in EQ mode have been disappointed because it feels a bit like a hack rather than design. It does work, though takes more fiddling than most EQ mounts. So, to be specific about your basic questions - with EAA the best things for DSO viewing are a fast telescope (low f ratio) and a sensitive camera (low read noise, high QE). Definitely get a dedicated camera, the 224MC or 290MM are two of the best cameras available for the money. Also check the ASI385, though it is a little more expensive. The 224 is in colour, and the 290 is black and white, but gives you more detail and fainter objects. Personally I found mono more fun and I don’t miss colour. At first I did (I have both the 224 and the 290) which is why I tried a colour camera. However, the extra sensitivity is more fun than colour for me. You may differ. Again... personal preference. Of the scopes you talk about… you are right about the 127 SkyMax mak. It's a great little scope but I'm not convinced about it for DSO EAA as a base since it requires extra bits to get working well. Planets and lunar it'll be great out of the box. Skywatcher Startraveler 102/500 Good scope but not really what you want for EAA due to the f ratio being too slow for DSO. I have one and use it for lunar and planetary. CA is an issue but it’s fine, it’s also a good for the price scope. EDIT: Sorry - I've just seen that I don't have one. I have the Evostar 102 - which is f11, not f4.9 - that's what the above refers to. The Startraveler 102 is fast enough for EAA use. Its a good price for a refractor, however... This is where personal preferences come in. At that price I'd actually prefer to spend a fraction more and get a newtonian like the 130PDS. But... my preferences tend toward cheap newtonian light buckets and expensive nicely made refractors! Most cheap refractors tend to have too many compromises for me which pushes me towards a reflector without CA. CA is less of a deal on a mono camera, so if you get the 290 you won't notice it so much (it's still there, but it's not so obvious). Skywatcher Evostar 72ED Good scope but you’ll struggle with some DSO. I have a 80mm refractor and my interest - galaxies - aren’t the best on it. It's fine for nebulae and our neighbouring galaxies. Great for grab and go. I really like 70/80mm for visual. Especially moon, planets clusters etc. Good on the AZGTI Skywatcher Evostar 80ED Very nice but if budget is an issue… the problem is refractors are relatively expensive for the aperture. Especially good ones. Even cheap good ones like this Skywatcher. Skywatcher 130/650PDS This should be fine on the AZGTI. I haven't used one on it, but others in the forum have. You can check those posts out or reach out to those users to see their experience. I've actually used my 150PDS on my AZGTI. It worked, it was slow to settle after a move, but it worked... (I've only done it once!). Don’t worry about mirror recoating. It’s like worrying about having to repaint your car. Maybe theoretically you have to if something goes wrong but it’s very rare anyone really has to do it except through choice or accidental damage. It’ll do DSO really well (there is a 130pds thread on the forums for pictures). It’s also good for visual if you pick the right eyepieces (check out the astronomy tools fov calculator). Collimation and it’s difficulty is overplayed. I have the 150pds. Yes collimation will be a thing. But for a beginner you won’t know or notice until you start trying to figure out how to make your observations better. Basically all it is is turning a few screws on the bottom of the scope and lining up some dots. It’s fiddly but not crazy hard if you have collimation cap which costs all of about £6. You don’t need a laser collimator or expensive assists. And… Even when you do do it, it takes a minute or two nothing more. It’s like sweeping the step, you may want to do it every month or two but it only takes you five minutes and isn’t that difficult once you’ve done it once or twice. And actually... maybe you don't care because you have more important challenges to deal with than a bit of coma. When you start to care about the coma enough, you won't be worried about it being difficult. Check these links out: https://www.firstlightoptics.com/other-collimation-tools/rigel-aline-collimation-cap.html https://garyseronik.com/a-beginners-guide-to-collimation/ So… for me it’s not a difficult decision. Get the 130PDS and the AZGTI and either camera you suggest. The AZGTI will run the 130PDS ok and it is a good telescope for EAA. Buy some nice eyepieces and it’ll be good for visual too. The 130 on the AZGIT will be fine for EAA and slightly bouncy for visual though not unbearable. You just need to be careful when viewing not to touch it too much. On the camera… do you like colour and less detail or b+w and more detail. That, to me, is your biggest unknown... Hope that's helpful!
  6. Just saw this post - a few days old now. For EAA I would not get that camera. It's a camera for astrophotography. It's a good buy for £200 but if you want a camera to do EAA - that isn't really what you want. I would strongly recommend a modern CMOS camera like those from ZWO / Atik / QHY etc. For your needs you can get a new one that will perform better at a similar price. If you want to get into astrophotography then I would go for it - but based on your other post, I don't think it is!
  7. There is much debate and a million ways to do things in astronomy - everything is a trade off. And it can be very difficult when you don't know your own preferences yet. If trying to get your head round the details gives you a headache I'm not going to confuse you with subtlety and/or balance! Here's my recommendations based on how I understand you. For detail, reasoning and explanation you can find it in my past postings if you search the forums. First -- congrats on the scope -- the Evo 9.25 is a really great one and will be amazing with a hyperstar (if that's what you're tempted by) pretty much top of the line, basically. For an impulse purchase, it's a good one. However, one thing not to get frustrated with is that, it's big and heavy and can be fiddly to set up. Don't be discouraged - with practise it will become easier. Also, the more you can keep the setup intact, the easier and quicker it will be to get going. One quick thing first though... I'd be careful about using it for solar. You run a serious risk of damaging the optics of your telescope and yourself! A 9.25 SCT is not really designed as a solar scope. Be sure you know exactly what you're doing before you point it anywhere near the sun. I have an 8" SCT and I wouldn't use it for solar. For me the risks are high for not very exciting results in white light, especially now the sun is quiet. Instead, I bought a dedicated solar H-Alpha scope. It's safer and you see far more. There are lots of options but combining a cheap refractor and a Quark eyepiece is a good one. But that's a different subject! If it makes you feel any better about spending the money on the Hyperstar - it's not an adapter. The Hyperstar actually changes the telescope design with specially designed additional glass. It's like a tiny glass telescope you insert into the bigger telescope to magnify the image from the mirror: there's a lot of fancy optics in it. Possibly a slightly controversial opinion but I wouldn't try EAA with a DSLR on a scope. I worked as a professional photographer for a while - so I know my way around a camera - and I found using a DSLR on a scope a massive pain that yielded bad results. I'd go straight to buying an astronomy camera you can use with your tablet. You want to see stuff instantly and relatively easily on your tablet. There's no easy way of doing that with a DSLR, and I found the technical frustrations in turned me off totally. So what should you buy... simply without giving you a headache! on details? For my money, by far the best bang for buck cameras are the: ASI290MM if you are happy with black and white ASI385 if you prefer colour Black and white lets you see more details and fainter things. Colour... is in colour! Personally, I thought I'd prefer colour, but I actually ended up preferring B+W because there is more detail. Both cameras will do everything you want very well: lunar, planetary and DSO. If you want the simplest thing that works on your tablet, get the ASIAir Pro: https://www.firstlightoptics.com/zwo-accessories/zwo-asiair-pro-wireless-astrophotography-controller.html I recommend the ZWO ASI kit because I've used them, they're well made, the company is helpful and they're really the only one stop simple solution in your price range that lets you put a camera on the telescope and look on you tablet in an app. Your biggest choice is to splurge on the Hyperstar straight away or get a focal reducer. Your telescope is not currently optimised for a camera, it's optimised for your eyes. To make it work better with a camera you need a focal reducer: either the Hyperstar design or one you can put in the eyepiece. Otherwise images will take too long to capture. You can get a decent one relatively cheaply to start you off: https://www.firstlightoptics.com/reducersflatteners/celestron-f63-focal-reducer.html This will get you going, but it will be slow. The Night Owl 0.4 reducer is much better but also much more expensive (I've also not used it/seen it used so I'm just going on specs and talk). However, when you get the hyperstar you will be amazed at the difference. It's not the same experience. Seeing images move, live on your screen at 15 or 25fps - not waiting for 15 seconds per frame - is a very different experience. For indoor viewing, on the ASIPro you should be able to sit inside and do everything from your tablet: control and viewing. Your mount should be controllable from SkySafari 6 or the Celestron version of it. The ASI app will allow you to see things from the camera. If you want it on your TV it'll be a lot more complicated. On iPad you can stream to a TV using AirPlay. For Android I'm sure you can do something similar with ChromeCast, or other utility. There may also be a bit of lag and so on. If, later on, you are interested in working with a computers to get performance you could also use a Windows Tablet/Laptop/Surface Pro etc with https://www.sharpcap.co.uk And do a bit more. (Since you ask about laptops, I'd personally go for a Lenovo Thinkpad or a Surface Pro. Get plenty ram (32+), and an i5/i7. It's just for astro you don't need a monster. However, if your laptop has a tendency to take a beating go Thinkpad. I used to drop my Thinkpad from about 4 feet onto the floor as a party trick to show how resilient it was. It never broke in five years and tens of drops. It was also ultra thin and light for the time. I met someone on their test team years ago. They used to do stupid stuff like throw them out of cars at 60mph, run over them and flush them down toilets and they'd take a real beating before they died, so I was pretty confident! I once poured coffee all over it by accident and Thinkpads have a drainage system that channels the liquid out. I killed the keyboard but it is a user replaceable module and a new one came the next day.) From your PC you can explore more astrophoto stuff or start streaming it to your 8K TV if you feel like a technical challenge! But I'd stick with the ASIPro for the moment. It's simpler easier and works on your tablet. And since you want colour, that makes the camera choice. So, to sum up buy the: ASI385 ASIAir Pro Reducer -- Celestron f6.3 and/or f4 Night Owl and/or f2 Hyperstar And that should do exactly what you want. There are many variations or alternatives, but it comes down to the trade offs of personal preference. I think this is the simplest and best version that should work for you. -- One final suggestion though... If you really have absolutely zero plans on ever using your telescope for visual then before you can't return it you may want to look at switching the actual optical telescope for a Celestron RASA telescope. Very few people actually go this route because it is very restrictive. You have to really want it! The Evo 9.25 is far more flexible. But... The RASA is a very similar to what you have bought, only it has a hyperstar-like optical element permanently built in. That makes it more sturdy and simpler to use. It always just works. The hyperstar can be fiddly to align and you need to be very careful when you change it in and out since your handling fragile optics. Focus and collimation at f2 can also be fiddly as someone mentioned. The RASA gets round all that. The big RASA disadvantage is that you can never look through it like a normal telescope. It is just a massive specially designed camera lens for astronomy. https://www.firstlightoptics.com/optical-tube-assemblies/celestron-rowe-ackermann-astrograph-rasa-8.html The 8" is slightly smaller and more portable than your 9.25, but it also comes in an 11" version if you have the money and space! You will need to buy/keep the mount for it (like your Evo mount), since it doesn't come in a package. The only other disadvantage is that it will have a very slightly wider field of view than your 9.25 with hyperstar.
  8. Light pollution. I was always interested in getting a telescope but didn't think it there was any point until I realised what you could see with new cameras.
  9. Ah. No alas I haven't bought it yet. I was waiting to see what was happening with Brexit since it was a Euro order from Germany, then Coronavirus happened and everything went on pause. I had just started thinking about it again. Truth be told I am also still in an indecision cycle (this has been going on for 2 years now...). I think the UNC will be best overall. It's the sensible purchase for what I want, but then I was thinking... the ONTC would be a better machine - I like the mirror movement option and the better quality, even if I don't need it much. I have the money saved up to buy it... and I don't think I'd ever spend that amount on something like this again, so since the money is there. Then I think... that's a stupid waste - I'd probably never notice the difference. Then I look at the exchange rate and decide to wait... and I was just starting to think about placing an order. So, sorry I have no experience of it yet! Let me know if you do buy one though!
  10. I think single Arp and Hickson threads could be a good idea. I certainly enjoy seeing different observations of the same objects from everyone. However, I suppose it depends on how much other people would want to post and it. I'd be happy posting to a single thread, but I don't get a huge amount of clear nights to get the scope out. If so, I would be inclined to start an Arp thread fresh rather than use this one. An Arp thread probably doesn't need my long intro at the top... and the Silver Needle shouldn't be in there. Happy to repost some of these though. I don't have a data table. Though I'll take a look at creating one. I use an observing list set up in SkySafariPro 6 (I use SS6 to control the mount). It's relatively rough and ready. It was quickly put together using the SS6 search function and probably has duplicates. I know that can be exported. I'll have to see if I can export it as an excel file or a CSV which could then be tidied up. I'll see what I can do. If I can do a useful observing list from my SS6 list, I'll start an arp thread. Otherwise -- you can start it and post your images first!
  11. I have been intending to spend time exploring the Arp catalogue for a while - particularly since I picked up the excellent Kanipe and Webb book. Finally we had a good streak of weather and I was able to get out the scope. The following are all from my usual location in Zone 2 London with the associated light pollution. I'm using a ASI290MM for mono and ASI294Pro for colour with a 6” SW PDS150 on an iOptron CEM60. The mount is overkill for the scope, but it has virtually no backlash and is great to use because it just works. I might also get a bigger scope one day… Unfortunately, my usual process of SharpCap observing, then re-examination in Jocular has been impossible since upgrading to macOS Catalina. This seems to have broken the Python installs on my laptop, so everything is SharpCap. Generally, I do 10 minutes per object. Some objects I let things run longer. In addition, if the weather is good enough I will leave the scope running on the last object of the night and retire to bed. One interest of mine is to see what I can get in my backyard in 10 minutes or so with 21st century amateur equipment relative to Arp's original images with state of the art 1960s tech at Mt Wilson and Palomar -- including on the 200 inch Hale telescope. As noted I have only 150mm of aperture, though I do have a much better sensor than film. Over three nights I managed to cover Arp 23, 29, 36/183, 40, 83, 84, 104, 105, 106, 193, 205, 214, 224, 232/137, 242, 269, 281, 299, 320, 337. I'm posting the more interesting ones below. If anyone is particularly curious about any others I'm happy to upload the images - but they're not too exciting. In terms of image processing, unless otherwise noted, all that’s been done is stretching, levels, curves and crops. Do note that these are all screenshots - and not even at full resolution either, they're over Remote Desktop with low compression. I have the original data and do sometimes re-process if there is something interesting. I usually use Jocular for that, at the moment I'm using AstroPixelProcessor. However, none of the images below are from APP, they're all screenshots. Where possible I've not cropped the SharpCap screen grab so you can see settings - though I sometimes reduce resolution of the screen grab to fit the post. Where objects are too small and I don't want to reduce resolution I've cropped in. Overall, I found that most of these were largely disappointing observations - particularly when I was using the ASI294Pro. The post may be more interesting as a real world example of how the cameras perform, over astronomical observational interest. However, this isn't a camera test, it's an observing session report. That said, one key observation is that over the three nights I made these observations, the ASI294Pro just can't get the details that the ASI290MM can. What you get in colour, you give up in detail. It's not a surprise, but I thought there would be more detail in the colour images. If you're interested in seeing these objects I strongly recommend Rick Johnson's website: https://images.mantrapskies.com/search where you can see spectacular images of all of these objects and more. He also provides excellent notes, some of which form the basis of information in this post. Arp 104 The system is at about 140-150 million light years distance, and the separation between the two galaxies is about 22,000 light years (https://en.wikipedia.org/wiki/Arp_104). A bridge of stars spans between them and spotting that was the excitement here - which didn't work, it’s too faint. I may return to this with the ASI290MM, since it has better resolution and more sensitivity, or I may reprocess the FITS files to see if I can see anything. The original arp image is here: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp104.jpeg Arp 269 This is another galaxy pair with a bridge. It's not as spectacular as Arp 104 however you can see some of the knotty texture across the system. The interacting pair is about 25 million light years distance. The level of star formation is similar to larger spiral galaxies - this is presumably triggered by the interaction and also, I presume is why the galaxy shows blue, here and in other images. The matter in the intergalactic bridge originates from the disc areas, and it is roughly between 4 and 17 million years old which is when the interaction occured (https://academic.oup.com/mnras/article/459/1/683/2608786). The original Arp image is here: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp269.jpeg Arp 281 Arp281 is about 30 million light years distant and NGC4631, the large edge on barred spiral galaxy, about 140,000 light years across. The smaller galaxy is estimated between 500,000 and 1 million light years distance from the larger galaxy. 10m52s @15s exposure Arp 320 10m 5s @ 15.9s exposure. This is also known as Hickson 57 and Coplands Septet. The group is about 400-450 million light years distant. Again, a disappointing level of detail here. There's just not enough resolution in the system to see a lot. There may be more information in the data, but that would require reprocessing. The original Arp image is here: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp320.jpeg And for a proper view of this cluster Rick Johnson's image is great: https://images.mantrapskies.com/catalog/ARP-GALAXIES/ARP320-NGC3746-NGC3745-NGC3748-NGC3750-NGC3751-NGC3753-NGC3754-PGC036010/NGC3753L4X10RGB2X10X3R2-ID.JPG NGC4244 Not an Arp but in the vicinity of some, so I thought I'd take a look while I was in the neighbourhood. This is the Silver Needle Galaxy, again, colour is nice, but for me it doesn't make up for the lack of detail. Part of that is the light pollution, no doubt. However, the ASI290MM would definitely be getting more detail in this. The galaxy is 65,000 light-years across and lies roughly 14 million light years distant. As ever, Rick Johnson has a great write up and set of images: https://images.mantrapskies.com/catalog/NGC/NGC4244/index.htm Arp 84 I was much happier with the outcome on this one. There isn't a huge amount of detail but you can see some of the interaction and the colour adds to the reading of the spiral, which I take to indicate a redder older core and bluer younger spiral arms. The galaxies are about 330 million light years distant. Arp's original's image is here: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp84.jpeg I returned to this with the ASI290MM and found much more detail. This was a longer integration at 76m 28s. That was 347x13.2s exposure. I know those numbers don't quite add up but I left this running when I went to bed and that's what SharpCap told me the stack was. There is also some stacking artefacts on the ASI290MM image, the repeated pattern of dots leading off the spiral arm - this isn't an object. You can see the repeated pattern in the lower right of the frame, as well as to the upper left. I'm not sure where they come from. I presume it to be some sort of dust on the sensor or scope. If anyone has any ideas - it would be good to hear. I'm sure there is more information in the ASI290MM data than you can see here, however it will need re-processing in APP. Using just the screenshots I combined the colour and mono images to get: Arp 224 NGC 3921, the larger galaxy is about 59 million light years away and is the result of a merger about 700 million years ago. I was hoping to see the loop structure here more clearly. It is barely visible, as you can see more clearly on the inverted image. Arp's original's image is here: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp224.jpeg Arp 193 I spent a lot longer on this than I would normally - 268x8s for a total of 35m 44s. This was for two reasons, first the Hubble images of this are quite spectacular and I wanted to see if I could push for more detail (https://en.wikipedia.org/wiki/IC_883). The internal dust lanes are stretched like candy and there is an interesting stream of stars extending for some distance away from the central galaxy. The second was that I made myself some tea, then got distracted looking at something else. When I returned some time had passed... The galaxy is about 320 million light years distant. It's about 65,000 light years thick and 131,000 light years long. The stream is not barely visible on the standard view. Inverted it is easier to see. Arp's original's image is here: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp193.jpeg
  12. For me the first thing I'd mention is the bad news... I think the most frustrating thing for EEVA will be your f7.5 refractor - certainly in terms of the experience. It’s not the end of the world, but when looking at near live viewing you want the shortest exposures as possible while getting as much light as possible. At f7.5 you’re letting in much less light into your camera than if you were at f5 or, ideally f4 or less. That makes everything slower and basically less fun since EEVA (certainly for me) is about instant gratification... as close to looking through the eyepiece as possible. On the upside… your 127 f/11 Mak on the AZGIT with a ASI224 will be a planet killer, and it’ll be great on the moon too. You’ll get really nice results with that. Those things are bright so light in the scope isn’t your problem. DSO’s will be slower to show up at F7.5 and f11 but they will eventually. It does mean your stacking and exposure times will be long. For instance I have an f4 scope and stacking 8 second exposures on my ASI290 would not be unusual to see galaxies. With an f/7.1 scope to get the same amount of light you’d need a 25 second exposure. Typically I feel I get a decent view of things after about 3 minutes. That means (if I have the maths right…) you’d be waiting about 10 minutes for a similar image. It's OK but not really instant either. Also, I use the AZGTI myself and 25 second exposures are at the edge of where I use it. You’ll have to be careful about your setup and being as accurate with your levelling and alignment as possible. A focal reducer will help, but good ones are expensive and very few are amazing. I have a decent but cheap TS Optics one. This one at FLO is also cheap (https://www.firstlightoptics.com/astro-essentials-eyepieces/astro-essentials-05x-1-25-focal-reducer.html, I have this one https://www.teleskop-express.de/shop/product_info.php/language/en/info/p676_TS-Optics-Optics-TSRED051-Focal-reducer-0-5x---1-25-inch-filter-thread.html) If you’re on a budget, then I’d look at one of those. That would take your system to under f/4. It’ll make your experience more EEVA speed and less astrophoto speed. It will reduce the quality of your views (they’ll be a bit more blurry) and it will make your FOV wider. On the upside, you can also use it on both your 127 Mak and your refractor. It may actually make your Mak a better EEVA scope than your refractor. However, the nice thing is, it gives you the option to use whichever you like best. Ironically the optics of your 10” Dob are perfect for EEVA - but you’d need some sort of tracking system. One upgrade that may be worth be looking into if you can cheaply get the goto addition for your dob. Or maybe some other form of simple tracking. It doesn't need to be too perfect since you’re interested in EEVA you don’t need an astrophotography level mount. You'll only really need something that will track for up to 15 second exposures. Rarely do I ever do exposures over 15 seconds and I’d say 2-8s are my normal lengths. That said, I do live in a very light polluted area, so that limits how useful longer exposures are for me. But that's a hard limit from pollution, if you are in better conditions even my short exposures will give you better views than I get. I have also seen people on cloudy nights post stuff from hand tracking their dob - but I’m sure that’s even less fun than it sounds. Another crazy thought though… you could put the focal reducer on the dob and you might be fast enough to not even need to track. At f/2 your exposures could be very fast and SharpCap will do the tracking with the stacking. You won't get much before you have to move the scope but it might be doable. Anyway things to play with and try once you have a camera. Another thing you might find fun once you’ve got your camera is if you have any fast photography lenses lying around (f/2.8 or less is when it gets good…), you can put the lens directly onto the ASI camera (you do need an adaptor but they’re not expensive) then use your GTI mount (or even a tripod). It’s wide field look relative to a telescope but the faster f/ratio gives you the really live viewing experience - you may not even need to stack to see things. I have a cheap old 50mm f/1.8 which works quite well. It's very wide of course, but it's fast - like watching video. If you’re looking at the ASI224 or the ASI290 I assume your budget is under £300 or so. The ASI224MC is for my money still the best colour camera in that price range. There are better colour cameras but you need to jump in price a little. The ASI290MC that you mention isn’t as good in colour. If you want colour in this price bracket definitely go for the ASI224MC. On the other hand… the ASI290MM — the mono version — is the camera I’d pick over any cameras in this price bracket and even well beyond. So long as your okay with mono. There are a few reasons for this. First, the ASI290MM is a far more sensitive camera. It’ll see in the dark in a way that the ASI224 doesn’t. This will help with your slower focal ratio. Because it’s a more sensitive camera you can use shorter exposures and see things faster. You'll need longer exposure times on the ASI224. I’ve got the ASI224MC, the ASI290MM and the ASI290Pro and the truth is… I use the ASI290MM most. It’s smaller, faster and goes deeper. When I first bought it I missed colour, and after about six months I bought the ASI294Pro trying to up the excitement. But I realised slowly for what I’m interested in (galaxies) colour is less interesting than exploring detail and depth. If I were really into nebula I might think differently. But the mono ASI290MM is a really versatile camera. There are better cameras for sure, but its just fun and easy to get images and detail out of it. It just works. Brand wise from my experience the ZWO cameras have been reliable, well made and the staff are very accessible. There are well maintained forums and Facebook pages. The company owner Sam can be found around Cloudy Nights and on other forums - especially his own ZWO one. I’d give ZWO a strong recommendation. Do note that I’ve not used other manufacturers cameras - I liked the first camera so much I've been brand loyal! Similarly, with SharpCap Robin who codes the program himself is available and answers things personally. I strongly recommend supporting him with a Pro license, and if you have any issues you can email him directly. SharpCap and the ZWO ASI range give you a great package for EEVA. I’d also give a shout out to Martin Merediths Jocular (to be found elsewhere in this forum) which is fantastic but that is not a professionally supported program, it’s mono only, still in development and requires more technical knowledge to get set up and running. Once you’re up and running comfortably with your EEVA set up, you should check it out. Personally with the ASI290 or the ASI224 I'd be surprised if you have too many performance any issues on your i3. The place where you might see sluggishness is if you are stacking large frames and changing the histogram in LiveStack. I’ve run both cameras on less powerful machines than an i3 and not had any problems. Plenty of people ran the 224 and the 290 on Atoms compute sticks when they first came out. I currently run the ASI290 and the ASI294Pro (which is a 11.7 Megapixels - basically a bit better than 4k at 4144×2822 since 4k is 3840x2160 or 4096x216) on an Core m3-6Y30, 4 GB RAM, 64 GB eMMC, Intel HD Graphics 515 and it’s fine. The ASI294Pro is the most resource intensive because it has big files. So is not ultra-snappy, but it’s is perfect happy live stacking and manipulating. With the ASI224 and the ASI290 it runs great. You should upgrade your laptop if you want a new laptop... But if you're looking to get bang for your buck in your EEVA experience I'd be looking at finding a way to get your system f/ratio faster before anything else. For instance, a 100 newtonian that you could happily stick on the AZGTI will run you about £100 (https://www.firstlightoptics.com/heritage/skywatcher-heritage-100p-tabletop-dobsonian.html or even https://www.firstlightoptics.com/heritage/skywatcher-heritage-130p-flextube.html). That will do much more for your EEVA experience than a new computer for £1000 or more. In terms of cable management, it does only become complicated when you want to move indoors rather than sit at the scope. The basic version is you need a USB cable from your computer to your scope mounted camera and that’s it. Everything else is optional. So… your final question — how do the camera specs translate on the business end… The simple answer is don't worry about it too much. Go to http://astronomy.tools/calculators/field_of_view/ or use the same tool embedded in the FLO page you linked to and put in the gear you’re looking at using. This will give you an idea of what you’re going to see on screen and that's by far the most important thing. Unless you’re interested in the details I wound’t get too deep into the pixel size and resolution -- it's not really make or break unless you have specific interests. And if you have those specific interests then you know what you want and don't need any explanations! If you really want detailed explanations you can also get into the weeds and play with this tool here, but don't let it scare you, the cameras you suggest are good: http://astronomy.tools/calculators/ccd_suitability In terms of the other specs the quick and easy way to compare them is to look for Higher QE (80%+) and lower read noise (less than 1.5e is good, 0.7e is excellent at the moment). If the QE is high, your sensor will capture all the photos hitting the sensor, and if the read noise is low, then you can stack those images without noise getting in the way. Quantum Efficiency is a measure of performance, ideally you want QE at 100% because that is a perfect sensor: every photon that hits that sensor is registered by the sensor. If a camera has QE of 80%, only 80% of the light from a star that hit the sensor are registered by the sensor. Read noise is an indication of how accurate the sensor is. Every time the sensor takes a reading (ie. snaps a picture) how many electrons in the reading are a result of accidental noise rather than actual signal created by the light. The closer to zero the read noise is, the better. If it was zero, every time the sensor said there is a photon, it would be absolutely correct. You can pretty much ignore most of the other specs unless as before, you’re into details, at which point you know what your looking for and why. Anyway... the short of all of this version is: I’d use SharpCap Pro on your existing PC. Then if you want a colour camera I’d buy the ASI224. If you want detail and depth I’d buy the ASI290MM, but it’s black and white. Don't worry about it too much and have fun!
  13. Forgive me if this is covered in Martins post - I only skimmed the linked post. The quick and dirty answer for performance is that with CCD you will always tend to be better with larger pixels (bigger receptors to collect photons) because you can’t bin CCD as effectively as CMOS due to noise. With CMOS sensors you can bin (add groups of pixels together to make a super sized pixel) with little to no penalty so pixel size is not something to worry about as much (it’s a little more complicated than that but...). Pixel size in CMOS cameras is usually important mainly in terms of your possible highest resolution (when looked at in combination with your telescope specs). There’s more to it than this, but my rule of thumb is go for smaller pixels on a CMOS all things being equal and larger on a CCD all things being equal. However, if I’m looking for a camera the important specs I’m looking at on CMOS are QE (as high as possible) and read noise (as low as possible) - and making sure the FOV matches my telescope for what I want to use it for. I’d then check full well depth to give you a sense of how much dynamic range you can get in a single exposure (larger well allows for longer exposures before something overexposed). But this is less important for eeva than for imaging if you’re stacking anyway. Pixel size in a CMOS camera is not indicative of sensitivity performance in and of itself. With the cameras you mention I have the 224 and the 290. The 290 is more sensitive by a large margin. Martin is right about the aspect ratio but actually for me that doesn’t matter since most things I’m looking at are very small in the frame. It’s just trickier to slew around by eye. The IMX290 sensor is old tech now (there are marginally better spec’ed new cameras ones I’ve not tried) but it’s still great bang for buck in the mono cameras. I think there are better colour cameras now (385??) than the 224 - though, again, more expensive. If you don’t mind mono and want a cheaper camera an IMX290 one is still what I’d recommend. I love my ZWO version and use it more than anything else. Keep in mind I’m into smallish galaxies so were I into nebula I may pick something different.
  14. SharpCap can seem complicated but you can safely ignore most things if you don’t need them. I’ve never used starlight live but I was tempted to buy a lodestar because it had such great reviews. With SharpCap I find I generally only touch a few sliders mainly gain, exposure, plate solve, focus and the histogram. There are extra tools but I often what’sNot helping at the time. Plate solve makes a huge difference and allows me to just jump directly to objects and they always end up in the center of the screen. There are some good SharpCap quick start guides - AstroJedi on CN has an excellent one posted. It’s worth playing around with it since you can try it free and add I understand SLL hasn’t been updated in a while. For me I didn’t want software limit hardware performance in choice of camera. Alternatively, maybe Martin can start a new business as an astro-software developer to fill the gap! I think Jocular is the best electronic observing software at the moment - even in development and problematic as it is now, it’s more fun to use because it’s designed around the things you want to do in EAA rather than ap / hardware control oriented.
  15. I tried following up on these myself last week with a SW150PDS and ASI249Pro colour and ASI290MM mono to see what I could see from my location. Not as much as Martin is the answer! So I think this post is going to be more interesting on a technical / curiosity front. However, to change it up I did try in one shot colour. All below are screenshots I've not fiddled with them to bring out more detail - which there definitely is on some nights - unless noted. Transparency has been very bad here recently, making light pollution worse. I’m going to experiment with some light pollution filters. However, if anyone has any other advice, I’d interested to hear it. One thing I notice is how I very quickly blow out stars to white as soon as I start stacking. That may be because I’m trying to get really dim objects most of the time, I’m not sure. WBL726 Exposure 11m32 (173@4s) I think this was the most successful of the evening in some ways. No real detail but at least you can start to see some variation in the galaxy, rather than just a smudge. It’s still pretty smudgy though. WBL 724 Exposure: 9m36 (18@32s) WBL 692 Exposure 10m8s (19@32s) NGC 7433 is in the centre of this frame. Again, no detail. WBL 685 Exposure 10m40 (35@32s) NGC7345 is in the centre of this image. You can see some of the cluster in the lower left centre. These are all using the a 1920x1080 sensor crop on the ASI294, the full sensor is much larger, but using it all it makes stacking and stretching slower on the m3 chip on my compute stick. I use the full sensor more on larger objects or if I’m just collecting data to look at later. I then switched to the ASI290MM mono camera that is more sensitive than the 294Pro. However, while things are easier to see I don’t know if there’s any more depth. Also, since transparency was the issue - there’s still not really any detail. This is the full 1920x1080(ish) ASI290 sensor. A little more on workflow for those interested. I usually use the SharpCap brain to set an optimal exposure time for 10m of stacking time. I find that's about optimal for me to start on an object so that I can see a few different things in an evening. What the brain comes back with varies depending on the conditions and I don't always find it works. It often gives a measurement too underexposed so can't find alignment stars to stack with. Some evenings I pick my own numbers based on the analysis of the gain/sensitivity performance of the cameras. Usually this is to reducing exposure times and increase gain to combat bad seeing with short exposures. Also if I want to try and get more detail I’ll use very short exposures. I didn’t do much of that on this run since transparency was the issue not seeing. I keep the full frame FITS images of the above in stacked and raw frames. and Martin’s excellent Jocular software has changed the way observe. I've just used screengrabs for convenience here. I will view on SharpCap in the moment as above to acquire data. As I said, usually for about 10 minutes. Occasionally I leave it for longer, sometimes less, sometimes I leave it overnight. I save both stacks and raw frames. Then, in more sociable hours or on cloudy nights, I take this data into Jocular and take a look to see what else is there. I used to stick data through APP but the AP workflow is time consuming and Jocular is much more fun to use. I also plate solve and annotate the images for my own notes if I’m interested. I wish there was an easier and better way to do this. I have found no user friendly plate solving / annotation software with the exception of PixInsight which is quite frustrating since it’s so expensive and not actually that user friendly either. The best I've found is uploading to Astronometry and waiting, then copying manually which is less than fun. Unfortunately, currently the snapshot feature isn’t working on my build of Jocular. So below is another rough Mac screengrab, though this time it is of the FITS data re-stretched in Jocular and inverted. Again, although there is no detail you can clearly see the two 15th magnitude galaxies NGC7345 (close to centre) and PGC69406 (centre left) and NGC7342 (bottom right) without too much trouble, which I think is pretty good for central London on a bad night thanks to technology.
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