![](http://content.invisioncic.com/g327141/set_resources_15/84c1e40ea0e759e3f1505eb1788ddf3c_pattern.png)
London_David
Members-
Posts
140 -
Joined
-
Last visited
Reputation
96 ExcellentProfile Information
-
Location
London
Recent Profile Visitors
The recent visitors block is disabled and is not being shown to other users.
-
As it happens I was looking at this on 3/1/21. Really sorry but I can't remember the total integration time or anything else - it was under 9 minutes total and probably about 5 minutes. Exposures were under 15 seconds and probably 4 or 8. Captured with a WO GT80 with the 0.8 reducer/flattener and an ASI290 on an AZGTI. Definitely more detail on yours! I think my seeing wasn't great.
-
Mead LX90 8" Needing Help
London_David replied to London_David's topic in Discussions - Scopes / Whole setups
Thanks for a quick reply!!! Hmmmm... One night I was out testing it within about 30 mins. Another night it was out for about 2 hours before I started using it. No fans though. There was no memorable difference in the performance in either night. I've heard stories about SCT's being a bit soft. Could it be that I'm over-magnifiying? It's incredibly disappointing if it is - my cheap 6" Newtonain has notably better views than I had last week! -
I've got focus problems, and I'm not sure exactly the cause. I have been given an 8" LX90 GPS - probably around 2000-2005 vintage - because the previous owner wanted something smaller and lighter. It's rarely been used since it was heavy and mainly has sat sitting in a warm relatively constant temperature living room and moved 3 meters outside four or five times a year, if that. Physically it looks in great shape with no markings and just a little dust around the edges. I used it a few times in the early 2010s and I remember it working well, except for a sloppy focus mechanism. That said, I was inexperienced then so I don't know for sure. Over a few nights at Christmas and New Year I tried using it again to see what shape it's in, expecting it to just work as before. Unfortunately, I couldn't get it in focus. No matter what I did it was always fuzzy. Smoothly turning the focus knob, stars and planets would start to come into focus, then would become a fuzzy blob, then go out of focus again. I looked at the moon which was seemed to be okay in lower magnifications, but at higher magnifications there was notable chromatic aberration. There was no detail on Mars only a fuzzy orange blob. Jupiter's bands weren't really visible and certainly no detail (or even a sharp edge to the planet). Stars would never come to a point. They'd always be blobs at higher magnifications and never seemed crisp at lower magnifications. This is using a Baader Hyperion Zoom 24-8mm and Televue Delos 6mm through a WO Star diagonal. The fuzziness started being notable around about 14mm in the zoom. Though once you saw it, you could just about notice it on fully zoomed out too. This was particularly true of the chromatic aberration you could see when looking at the moon. As far as I know I did everything correctly. I let the thing cool down, there was no dew or fog on the front plate (though dew and frost was an issue on some nights when I used a hair dryer to get rid of dew occasionally). I even took the diagonal out of the chain using the Baader and it didn't make any immediately visible difference to the image. The best I can describe is that it looked similar to when there's dew on my secondary mirror on my Newtonian. The Meade image was probably blooming a bit less than when that happens, dew is usually quite obvious, however here at first glance using lower magnifications it seemed almost okay. There was no dew or frost on the Meade front plate or the optics that I could see. While I always remembered the Meade focus mechanism as very sloppy and horrible to use, historically that didn't effect me getting the image into focus. Plus there was the chromatic aberration. I looked at the collimation on a star by going fully out of focus and looking at the concentric circles, and it seemed to be the correct pattern, and tube currents seemed okay. I may not have done that test right - I'm not sure, I have a newtonian and a couple of refractors, this is the first SCT I've got. I watched a YouTube video and tried it out in the cold, so I may have missed something. I had a William Optics GT80 next to it and my first thought had been that seeing was bad. The humidity was between 80-95% across the different days I tried it but on the forecast but the arc second resolution on the forecasts was okay and I've seen better views in worse conditions with my 6" Newtonian. To the eye stars lower down had a bit of twinkle but were pretty solid high up and I was at a dark site without much light pollution. The WO seemed fine. Jupiter would show clear banding and looked better than on the Meade (though to be fair that was using lower magnifications and I've had better results from the WO scope elsewhere). Also, the problem with the Meade was consistent across several nights. Could seeing really have been similarly bad every night? Jupiter was low in the sky but Mars and the Moon were not. I also used the WO scope with a camera and while the seeing definitely wasn't great, I still think it has to be a problem with the Meade. The previous owner also said that they could never get it in focus either, and had told me previously they struggled to see Saturns rings clearly. However, I was thinking the previous owner needs glasses and sometimes struggles to find focus with my refractors - which are fine - so I wasn't convinced anything was actually wrong until I tried it myself on Jupiter and Mars. Does anyone have any ideas? Could the seeing have just been that terrible? Was I just cranking up the magnification too high? Could I have had dew or frost somewhere I didn't think about? Where would the chromatic aberration come from? What should I do to test it? Or fix it? Possibly relevant to what I do going forward: I've wanted an SCT for a while and was considering a C8 until I was offered the Meade. My intention was to defork it (I have a CEM60 on a permanent pier) and get a Baader Steeltrack focus for it. My interest is galaxies and planets. So I'd probably be putting a focal reducer and a camera on it 50% of the time and visually looking at planets for the rest. The C8 is still better for me overall than the Meade -- however, I'd have to spend a lot more money to get one! This one I hoped might just need some mounting rings and a focus upgrade. If it's all too complicated to fix though, maybe it's better selling the whole thing... and buying a C8. Any thoughts are welcome!
-
While I largely don’t disagree with the maths or description, as a practical matter, I’m a bit confused. You’re essentially saying with extra aperture the £1k 294Pro on a 3k 10” will work similarly (a bit over 10% better) but in colour, to the £300 ASI290 can on a £179 5” telescope. The colour sensor and the bayer matrix, don’t play a large part in that performance change. If you put the ASI290 on the 10” RC it will still detect fainter objects, with more detail than the ASI294Pro. Or, if you are limited by the atmosphere and you are oversampling on the 10” f8 with 2.9 um pixels - you could bin it to 5.8um square pixels (bringing the pixel area size closer to the 294 anyway). That will detect much fainter things than the 4.64um pixel size colour bayer ASI294 o matter what you do since the ASI290 still has a higher QE. To be specific on the IMX290 too, we may be talking at cross purposes here, but it’s a quad bayer design which isn’t quite the same as the layout as the diagram you show. The quad bayer is physically laid out with 2x2 grouped colour pixels that are binned in normal mode and used as double exposure in HDR mode. So in your diagram each pixel on your bayer diagram should actually show 4 pixels in it, and the sensor in HDR does double exposures two short and two long on opposite cell sites then combines them for read out. Is that the proper debayering you are referring to? While I have read talk about reprogramming the SoC to get access to the underlying quad pixel structure, as I understand it that requires more than just post processing and software debayering. Generally the best regarded debayering algo for the back illuminated Sony chips like the IMX294 in RGGB order is the adaptive airy disk on APP, however I’ve not seen that implemented on any real time program. Do you have a recommendation - I am alway looking to test new options? Going back to the sensors, I’ll clarify what I meant - if two sensors are the same chip design and one is mono and one is colour, given all else is equal and existing technology, the mono sensor will always outperform the colour in terms of detecting photos and resolution. This is because the matrix colour filters block light, reducing the photos hitting the actual photo site. When manufacturers change sensors for mono they remove the filters so each pixel can detect all photons, not just those of the right wavelength. If you bring in cost into the equation, mono sensors are indeed generally more expensive than colour sensors of the same design for this reason. Mono sensors are a niche market and don’t have the same economies of scale. However, mono sensors of a different design - especially if the sensor size is smaller - can be cheaper and have a better ability to detect photons. Generally, given other things being similar, you alway pay for more for larger sensor size. So to bring it all back to the OP’s question: it is individual choice. Some people like colour, some don’t care one way or another and others prefer clarity of shape and detail over colour. I surprised myself by discovering I am in the “don’t care” category. I thought I needed colour, but I found speed and detail more fun about 60% of the time. On any given scope the 290 gives me a more detailed picture faster, so it’s the one I tend to grab unless there’s a specific reason for colour. The main point for me is that I do this for fun, so if the camera is more fun to use, the observing is more fun to do. But what you find fun may change, and you just have to figure out for yourself!
-
Generally I’ve set myself different levels of goals based on my own interests. The first thing that got me into this was seeing AstroJedi on CloudyNights post an image of the relativistic jet in m87 taken from inside SanDiego light pollution. So M87s jet was my first goal - which took some time for a variety of reasons (not having a telescope was the first one...). I have a list in sky safari that is my “season” goals. I’d have a few of those that were relatively tricky or needed multiple observations (or upgrades in equipment) to get. M87, the Apollo landing sites, pillars of creation, an Einstein ring, gravitational lensing, that kind of thing. Then each night I would also have a few objects that I’d seen in books or people had mentioned in the forums and wanted to check out myself, that would be the “evening” goal. Sometimes the evening goal was something someone had posted - an image that had no detail and I wanted to see more. Sometimes the opposite, images with amazing detail and I wanted to see how close I could get with my London light pollution. Other times it would be something I’ve read about in a magazine or I’ve heard of in a lecture. Lastly, I keep an eye on the transients to see if there are any supernova to check out - if there are that’s usually top of my list. I will also go with the flow sometimes. I use sky safari to control my mount and if I saw something on the map that looked interesting in the vicinity of where the telescope was pointing, I’d head over to take a look. There is so much to see that it can seem that there is nothing to see. Picking things at random can show up amazing things you otherwise wouldn’t find, but most of the time I’ve found a lot of things look similar or lack detail from my location. Going with the flow is actually often quite unsatisfying. The best thing for me has been the forums and books. The Annals of the Deep Sky by Kanipe and Webb are great. I love the Cambridge Photographic Atlas of galaxies and the Cambridge Arp Cataloge. Sometimes I’ll just get them off the shelf and jump around randomly on the pages and point the telescope to see what I can. Arp is particularly interesting in that respect not just because the objects are fascinating but also because that catalog has all the original plates from (mainly) Mt Palomar observations. It’s fun seeing what a small modern 6” telescope and camera can do relative to what was the biggest telescope on earth with film. Sometimes it’s pretty amazing how close you can get. Generally I have five or six objects for an evening and spend between 3-30 minutes stacking, mostly about 10 if it’s interesting and 3 if it looks like nothings working. Sometimes I leave the telescope running on an object after I go to bed and reprocess the data to see if I can see more later. Any time I read something about an interesting object I’ll add it to a list. I don’t have much of a method other than checking those out if they’re near by or in a good position like the zenith. I’ll also keep an eye on general goings on. Mars, for example, I made an effort to check out on the evenings around opposition (scuppered mainly by weather alas). I also almost always look at a planet, the moon, or Orion if they’re in the sky too, maybe a globular cluster - either way something easy and bright. If you’ve spent a few hours failing to see anything other than fuzzy noise it’s nice to look at the easy spectacular stuff so that at least you’ve seen something that night.
-
I’ll give a shout out to recommend a cmos camera for the simple reason that you’ll get (for most people in most situations) a better performing camera, cheaper. In addition, with low read noise CMOS you can bin with very little penalty (treat multiple pixels as a single pixel to get more sensitivity, at the cost of lower resolution). These days CCD sensors are being manufactured by fewer companies since they are less competitive on price and performance. When I started I was concerned about having to pay thousands for a camera, however the costs of cmos sensors has dropped rapidly as the quality has risen. You can get really excellent cameras for a few hundred pounds. Martin is right though, make sure you’re matching the sensor size to your scope for the things you want to see. In terms of field of view you can crop in, so a larger sensor is less restrictive than a smaller one. Most important is that you need to make sure you are not under sampling (too little resolution due to the pixel size) the objects you want to see. Do try to match correctly, but oversampling is much less of an issue because the cost is lower sensitivity which you can compensate with exposure and on cmos, binning. And you will need a driven mount. I have actually done dso eaa without a driven mount but I was using a camera lens not a telescope, so I had a very fast lens with a wide angle view. The stacking software did its thing as normal for a bit before the image slid off screen. The main advantage was speed of set up. Even then, it was more trouble than it was worth. The only exception I would suggest is if you are only interested in a live view of planets or similarly bright enough objects where your exposures are under the 0.1s range . Again, even then you’ll be knocking the telescope repeatedly to keep things in view and it’ll be a bit tedious.
-
I love my mono ASI290MM for eaa more than my colour camera (294Pro which is about 3x the price...). It was a surprise to me, but the main reason is that it has shows better detail and can see in the dark better. The lack of colour wasn’t an issue after I started noticing the lower resolution on the larger pixels camera. I’m a firm believer now in oversampling, but that’s a bit off topic. The main thing for me is that the mono 290mm is a bit more plug and play too because it’s a smaller sensor, needs less light and you don’t have to fiddle with the colour sliders to balance your image. Most mono cameras will see more with better resolution than a similar colour sensor - for the reason than barkingsteve said. I do tend to look for galaxies and other small objects so the small sensor size isn’t an issue for me most of the time.
-
All good advice above (especially that the faster the f ratio of your scope the better it is for eaa) so I’ll stick to details on the cameras. I have the 290mm the 224mc and the 294pro. I’m on the verge of upgrading to the 533. I’m also a Mac user. Those are the four cameras I’d be looking at still. The 290mm is easily my favourite. But you need to be good with mono. I’m quite happy observing stuff in black and white if I can see detail and structure. It reminds me of the old image plates from observatories. I still think the 290 is the best bang for your buck you can get at the moment. It’s small, fun, frame files are not big and most of all the 290mm just sees more stuff in the dark. I’d even buy one of the minis as a second b+W camera just for fun if you have the money. Do not, however, buy the colour 290mc. If you want colour the 224 is the cheap option and the 294pro is substantially better but more expensive. It would be true even without the cooling on the 294pro. I’d say you get a couple of magnitudes deeper with the 290mm than you do with either colour camera. The 224 is noisier and just a bit more limited. However, the 533 is the top pick for me. I don’t own one but I’ve been doing a lot of research on it... Having looked at the discussions on cloudy nights and examining the new chips specs it’s the first real bump in performance in a few years. A lot of the camera features for a while have been more advantageous to ap. The 533 seems to have similar (maybe even better) performance than the 290mm but in colour. If the 533 is out of your price range and you still want colour, then the 385 is the next camera down that I’d be looking at. Probably above the 294pro. Performance wise they’re similar but the 385 probably has the edge for eaa while the 294 has the edge for ap and applications where cooling is helpful. And for mono... the 294mm is the top of the line at the moment - expensive though. fov - the 294 abs 533 are much bigger sensors with far more real estate. This is good and bad, mainly good. The bad is that each whole frame can be a large file size abs slow to write to the computer. The good is that you can get much bigger (or multiple) objects in view. Also - with all those sensors you can crop in so it only reads a small part of the sensor. That means the fov you see on astrotools is actually the _biggest_ image size, if you only care about a planet or a small galaxy you can have the sensor crop in to read a small part and the file size will reduce and it will speed up the read. ZWO - I like the zwo cameras a lot. They’re helpful in the forums, keep releasing new products and the gear is reliable and well made. The people that run the company (Sam I think his anglicised name is) are astronomers themselves and clearly use their own gear. There are other manufactures and cameras and a lot of them use the same sensors so the performance will be similar or even the same. The main difference will be in some of the buffering systems and build quality. For me, I be been very happy with my zwo camera so I’ll probably keep buying from them especially since they seem to always be first to market with new tech. Amp glow - is not something I’ve worried too much about unless it’s ap. A lot of the objects I look at are small and don’t cover the frame. Also, it’s easy to sort if you have software that can apply darks in real time. Amp glow is actually most noticeable on the 290mm and 224. The 290 can be quite bad actually, but I sort of forget it’s there because the camera can see in the dark so well. The 294 does have amp glow too but most of the criticism has come from ap useage. For ap 294 is great especially because of the full well depth but it does have some problems that the similar asi1600 doesn’t, so there have been mixed reviews about it. Pixel size - the quick rule of thumb is that on ccd cameras bigger pixels are better, on cmos smaller pixels are better - even that means you are over sampling. On any of the zwo cameras mentioned here the read noise is low so you can bin with effectively no penalty. That makes the camera even more sensitive. In addition, on the nights you have great seeing, you can get better images. Also, I’ve found that some nights you can go to very short exposures (under 1s) for dso and get even more detail than you would expect - lucky imaging works if the camera is sensitive enough which the 290mm is close to. Since I live near the center of London with the highest levels of light pollution, I’ve been trying to get detail over depth these days since I bottom out due to sky glow. Not that there’s been a lot of clear nights here this summer... Macs... unfortunately macs are not well served for Astro software. The asi software is good though it’s limited compared to something like sharpcap. I tried lots of things and in the end gave up. I bought windows 10 to use with parallels which I run on the Mac. I also bought a small windows 10 pc for the telescope. I use both, mainly I Remote Desktop from my Mac to the windows 10 scope at the telescope. I can do that wirelessly from inside my warm house... if I’m at the scope or out and about I’ll hook up the Mac running windows and not use the mini pc at all. Software wise I use sharpcap pro which is excellent. It is feature loaded and you don’t really need much else. If you really can’t stomach a windows machine and nothing on the Mac is going to work for you, the asiAirPro is a really good option. The one bit of excellent Mac software is Jocular - which Martin - who created it - can tell you more about himself if you ask! It’s a bit more complicated in the set up, but I really like using it with my 290mm. Last time I checked it didn’t do colour. So, to cut a long story short... I’d get the ASI533 if it’s in your budget!
-
I always use plate solving through sharp cap. It makes everything much easier. Before I got my computer hooked up (or if I don’t have it with me) I would align and do smaller gotos then align, star hopping and aligning my way to the faint stuff. Most of the time now I use plate solving on sharpcap. I have the Azgti which I mainly use with an f5 71mm. I use a win10 pc with sharpcap pro, and sysnscan pro. I also have the synascan pro app on my phone. I connect the pc directly to the mount by wire, that’s required if sharpcap is to control the mount. The phone connects to the mount Wi-Fi. I generally just do a quick north level alignment on the mount - with a red dot finder. Then each time I select to goto a new object in the synscan app, it moves, then I click plate solve on sharpcap and it then automatically moves to correct the position and align the mounts model. If you’re correctly levelled it’s pretty accurate after the first goto. Sometimes it’s out but it doesn’t matter because the plate solve fixes it. This happens more if you’re jumping to different parts of the sky. The only thing to remember with quick alignment and plate solving is that speed is almost always at the expense of accuracy. Plate solve will sort goto issues, but if you need/want longer exposures you may have to level and align more accurately.
-
Help for a lost soul with very little astronomy experience.
London_David replied to Mackem's topic in EEVA - Discussion
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. -
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.
-
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.
-
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!
-
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!