KP82

I'd pick a 4 - 5" ED over this 6" achro anytime. You get refractors for wide field, high contrast and pin-point sharp views. If it cannot deliver, it isn't worth it. For £500 a decent 10" dob will be far better for the money.

Mak would be too slow for galaxies. A C8 with a 0.7x reducer would be a far better choice for small distant DSOs.

Personally I wouldn't bother switching to anything with a similar focal length for imaging unless the current scope had very poor colour correction or was way too slow. If I were to choose something different from ED80, I'd go with either Esprit 120 (840mm FL) for smaller targets or ZS61 (360mm FL) for wide field. Another path would be a 1000 - 1250mm fast newt but this will require skills, a good mount and good seeing condition for high res imaging.

Unless the ES 80 is the FCD100 version, go with the ZS73 or for even less money Altair 72EDF which is essentially the same scope.

It will complement your C8. The refractor will produce wide crispy views that are very pleasing to look at. Just don't bother with high magnification on these fast achro.

Forget about the polar scope and use your guidescope with your guide camera for plate solving polar alignment. There is no need for star alignment. Issue GOTO commands from the handset (if using the firmware update cable) or a planetarium software (if using EQDIR) then use plate solve to centre on the target. The L Enhance filter is a tri-band narrowband filter that severely cuts the amount of light going through it. Because of it, the stars would be too dim to show any obvious diffraction spikes (they are still there just too dim to be seen). You may want to use a different method like the FWHM measurement for focus adjustment. ASIAIR is basically a raspberry pi with a power regulator and some custom software based on INDI. The pi has a combined USB power output limited to 1.2A. If you attempt to draw anything more than that, your USB devices will become unstable. Having dew bands plugged into these USB ports will definitely exceed the limit. You could either get a USB to 2.1mm adapter and plug them directly into the power regulator of the ASIAIR or use an active USB hub. Also you need a 5V/3A power supply for the ASIAIR. Otherwise the pi will crash due to insufficient current.

Hello Steve, welcome to SGL. First of all although I understand you'd like a scope that would cover as many of your requirements as possible, sadly there is no such "do it all" model I'm afraid. Your budget of £550 will be able to get you a decent setup for visual, but for DSO imaging you will have to spend a lot more. The scopes you've listed are strictly for visual only with maybe some quick snaps of the Moon. If you get one of them and later on want to start imaging, you will have to buy a completely different setup. Therefore in order to maximise your current investment, I'd suggest something else. There are scopes that can get you started on visual for now and later on be adapted to imaging with some upgrades. Since you're doing an astronomy course, I'd recommend a manual mount over a GOTO. It will not only help you familiarise with the night sky, but also allow you to put more of your budget towards better optics. Skywatcher 130PDS: https://www.firstlightoptics.com/reflectors/skywatcher-explorer-130p-ds-ota.html Skywatcher AZ5 mount: https://www.firstlightoptics.com/sky-watcher-az5-deluxe/sky-watcher-az5-deluxe-alt-azimuth-mount.html The AZ5 mount is compatible with any standard photo tripods, so if you've already got a heavy duty one with your Canon 800D you can opt for the mount head only rather than the mount/tripod bundle. This combo will leave you some spare cash for eyepiece upgrade and a cheshire collimation ep. When you're ready to dabble into imaging, you can simply buy a motorised EQ mount + t-ring + coma corrector and then move your 130PDS OTA to the new mount to start taking pictures. There is also a much more portable alternative, the Skywatcher Evostar 72ED: https://www.firstlightoptics.com/pro-series/sky-watcher-evostar-72ed-ds-pro-ota.html. However you will have to sacrifice 60mm of aperture (significant) for the backpack portability compared to the above reflector.

Good outcome at the end. I'm glad for you.

Your startravel 150 being f/5 might be too fast for the 38mm Panaview which has poor edge correction on fast scopes. Hence why I suggested those more expensive eyepieces earlier. From my experience, the stock level on Altair website isn't always accurate. If I were to order something from them, I'd get in touch with them to find out the stock level first.

The Altair, RVO, TS optics 72mm and WO zs73 are essentially the same scope. WO like to claim extra 1mm aperture on many of their models for marketing reasons. WO zs61 and Altair 60EDF are again the same scope. There are two version of Sharpstar 61EDPH, mk i a doublet and mk ii a triplet. According to some threads on CN, colour correction on the mk ii isn't as good as what would normally be expected from a triplet. WO Cat 51 is strictly a widefield imaging scope. But if that's the type of imaging you'd like to do, it is very good. SW ED72 is another good choice and a lot cheaper than the above. Most of these are out of stock at the moment. So if you need one asap, your choice will be down to availability rather than brand names. The SW startravel 150 is a fast 6" achro, so not suitable for high magnification due to high amount of CA and spherical aberration. But since your main interest is in DSOs, it shouldn't be a problem for you. I'd recommend a wide angle eyepieces to go with it like ES68 24mm, Morpheus 17.5mm, Nagler T5 16mm, etc. If you get a 2" diagonal, you can also take a look at those 2" WA eyepieces in the 30 - 40mm range.

Liveview with a crosshair overlay is definitely going to be more accurate than a standard ep for star alignment. Not familiar with the DARV in APT, but I used to do drift align in PHD2 for every imaging session in my previous house. When adjusting the azimuth, PHD2 would select a star close to 0 DEC and near meridian. There was a tree obscuring the views near the celetial equator, so I always selected a star around 7 DEC. When adjusting the altitude, PHD2 would select a star 60 degress to the East or West and still close to 0 DEC. I always chose a star at about 3 - 4 DEC as I had very limited views of 0 DEC to the west because of the garden fence. The resulted PA was good enough for imaging.

Could be tube current. But if the orientation of this weird star shape does not change with the rotation of the OTA after the scope has acclimatised to the outdoor temperature, this could suggest a mis-collimation in the lens.

You already have most of the necessary equipment and I assume you have read and understood the general process of DSO imaging. To answer your questions: 1. It doesn't have to be a triplet. Any scope with good colour correction and a fast focal ratio will do although triplets do offer the best control of CA among refractors. The sharpstar quadruplet is a petzval design with built in flattener. This will save you some time from working out the optimal spacing yourself. However if you plan to use the scope for both visual and imaging, pay attention to the backfocus distance in the specs of those quadruplets as some of them are specifically designed for imaging only and do not have the backfocus to accept a diagonal. 2. Brand name doesn't matter. Pick one with a focal length that suits the targets you plan to capture. Also it depends on your budget. In terms QA, SkyWatcher, William Optics, TS Optics, Altair, Sharpstar, etc are all about the same. Sharpstar manufacture their own scopes whereas the other four are just different brand names for scopes that come out of the same 1 - 2 factories (Synta, Longpern, KUO, etc.). Vixen is a good mid-high range Japanese manufacturer if you're after Japanese quality lenses. Finally there are the premium brands like Astrophysics, TEC, Takahashi, APM-LZOS and CFF which all offer some sort of minimum guarantee on the optical quality. 3. Skywatcher have their own dedicated series of imaging refractors, Esprit. 4. Most 80mm scopes have a focal length between 400 and 600mm which are suitable for many DSO targets. They are also fast enough (~ f/6) and can be made faster with reducers. They are much lighter than say your 150ED, so a lot easier on the mount. Your AZ-EQ6 will perform well effortlessly with an 80mm scope. Also the relatively shorter focal length will provide more tolerance for tracking errors in the mount. 5. Refractors generally do not have collimation issues and are easier to handle for beginners like us. So if you're more familiar and comfortable with them, stick to them. Dedicated imaging newts, hyperstar and RC while offering higher resolution or super fast focal ratio will require more effort to get good results, therefore are best left to the advanced folks. BTW I'd strongly recommend using your DSLR over the 224mc for DSO imaging. You may want to get it astro modded unless you plan to get a dedicated cooled camera soon. I'd also advise you to read the books mentioned in the previous post and familiarise yourself with the capture and post processing software.

To use computer controlled high accuracy GOTO for visual, take a look at this thread I created.

All looks good to me. 57.6mm is actually a good starting point for the subsequent trial & error to find the exact backfocus because the focal length of your scope is 480mm which is closer to the lower end of the 400 - 600mm working range and will require slightly more backfocus than the default 55mm theoretically.

The 55mm backfocus is the distance from the base of the T2 thread on the FR/FF to the surface of the camera sensor. In your case if you remove the front plate of the efw3, the backfocus is going to be 34.5 + 17.5 = 52mm. To reach 55mm, a 3mm T2 extension is required between the FR/FF and efw3. However because you need the supplied the M42 adapter to connect the the efw3 to the imaging train, that adapter may already measure 3mm and you don't actually need any extra extension tubes (if not, fill the remaining gap with appropriate extensions).

The FR/FF goes right between the focuser and your camera. It's a standard 2" push fit design, so just slot it into your 2" eyepiece clamp on your focuser and then attach the camera along with the filter wheel to the T2 thread on the FR/FF. The backfocus on your 1600mm is 17.5mm and the atik efw3 adds another 41.5mm. So you're already at a total backfocus of 59mm which is more than 55mm required by your FR/FF as shown on the specs page. However since this is a universal FR/FF, the optimal backfocus isn't always 55mm. The closer the focal length of your scope is to the lower end of the working range (400 - 600mm for this particular model), the longer the backfocus is going to be. You will have to work out the exact number yourself by trial and error. According to atik website you can remove the front plate of the efw3 to reduce its backfocus to 34.5mm, then insert additional T2 extension tubes to reach the desired backfocus.

Well you've got the perfect affordable DSO imaging kit. I don't know where you've read that ED80 isn't a good imaging scope. Care to share the links? You may want to get your 200D astro modded if this is going to be your dedicated camera. While it's inferior to a proper astro camera with set point cooling, it is still capable of producing wonderful results. Unlike dedicated astro cameras with set point cooling which can produce dark libraries for different temperatures and keep re-using them, you will need to plan in the time required to take darks at the end of each imaging session with your dslr. For polar alignment I'd strongly recommend sharpcap pro or polemaster. Learning the capturing and post processing software is just as important as how to operate all these equipment. For Canon DSLRs, BYEOS is a wonderful piece of capturing software. But if you plan to switch to a dedicated astro camera, you may want to look into SGP or APT. All of them have built-in (or rather communicate directly) plate solver. Then it's PHD2 for guiding and dithering. Finally DSS and Photoshop for post processing, or PixInsight if you have the money and are serious with this hobby.

If you're looking for better views than your current 8" dob, I'm afraid you won't be able to find anything that is more portable. A lot of the people have suggested a 6" SCT or Mak, but I'm going to point you to something different, SW Evostar 120ED. It doesn't have the same capability of light grasp as the dob, but it offers both unobstructed high contrast views and portability. It can also be used for astrophotography should you wish to try that in the near future. As for the mount, EQ5 will be sufficient for visual whereas HEQ5 will be the minimum if you want to do imaging.

You will be fine with a 4.5mm on an 80ED. 133x is still a reasonable magnification for this scope and good for observing Jupiter.

Living in a suburb location with no direct light pollution nearby makes star hopping doable. In this case I'd strongly recommend a manual dob. An 8 or 10 inch one would serve you well for a long time. If you ever want to get into imaging like you mentioned earlier, you can grab an 80ED doublet with an EQ5 GOTO mount in the near future.

While dusts on the lens are unavoidable, the amount that was seen on your brand NEW scope is not acceptable. My gut feeling is this scope was a open-box customer return. Reading the reply from this vendor, I'd say get a refund and buy somewhere else.

f/7.5 is considered a medium to slow focal ratio, so almost every eyepiece on the market will work well on it. The BSTs have an average eye relief of 16mm which should be enough for glass wearers. ES68, Vixen LVW and Baader Morpheus all offer good eye relief. But you'll be disappointed with those 82/83 degree eyepieces (e.g. ES82, TV Nagler) as the eye relief on those while better than plossl is insufficient for glass wearers.

Unless you're going to use the fancy features (e.g. afocal imaging) offered by the Hyperions, you'd be better off with BST starguiders which are 40% cheaper and perform just as good if not better. You will have to sacrifice a little fov, but you probably won't notice it most of the time. For ~£100 68 degree eyepieces if you have the budget, ES68 and Vixen LVW (discontinued, so have to look for used) are better choices. My recommendation would be to get the BSTs to cover most of the focal range, then get 1 or 2 ultra wide eyepieces for the beautiful widefield views offered by your ED doublet. ES82 and Baader Morpheus are good choices that won't break the bank.

Google the terms "air spaced" and "oil spaced". You will be able to find detailed explanations on the pros and cons of them. In short both "air spaced" and "oil spaced" lens designs are used by top tier premium refractor manufacturers. For example Takahashi and LZOS use air spaced whereas TEC and CFF use oil spaced. Astrophysics uses both.