KP82

It does. I mount my synta made SW evoguide 50 in it.

Rather than moving the whole OTA up in the rings I'd recommend getting one of these: https://www.firstlightoptics.com/william-optics/william-optics-120mm-saddle-handle-bar.html Very handy for mounting finder/guider closer to the axis. I've got one on my 72EDF.

I see what you mean. Placing the centre of mass of the finder close to the axis is definitely going to minimise its influence on the DEC balancing.

The moment arm of the ED80 is pretty short, so I doubt the slight imbalance due to different eyepiece weight would do any harm to the DEC bearing and stepper motor. If you can already achieve balance with the finder mounted on the focuser, moving it forward onto a bar/saddle between the tube rings won't make any differences (well ok for imaging this does help reduce flexure). Personally I only mount my guiding this way when using the 72EDF as it's way too tail heavy.

Could it be that the DEC axis in your old mount was a bit stiff? Maybe that's why the slight imbalance was not detected. When imaging I always rack out the focuser to the same position where it achieves the focus after attaching the camera and guiding setup first, then double check the balance in both RA and DEC. I actually mark the position on the counterweight bar and dovetail bar to save time. I even take a few pictures of the whole setup as a reference when it's fully balanced in case the marks get rubbed off. For visual precise balance isn't crucial, so I normally just use my most used eyepiece (ES68 20mm) for reference. Fortunately the majority of my eyepieces (except for ES68 34mm) weigh about the same and I only need to move the focuser a couple of mm to achieve focus with different ones.

All I know is that there is much smaller chance of getting a lemon from the premium brands, so you're effectively paying for some kind of guarantee of minimum quality. But many other brands have also started to offer test reports to guarantee minimum optical quality (e.g. Tecnosky). There are a few other benefits. For example LZOS use full steel for their lens cells. This minimises the chance of pinched optics in cold climate compared to the other materials. AP, TEC and CFF all produce oil spaced lenses which have faster cooldown and slightly higher light transmission than air spaced ones. Part of the reason why FSQ85 amounts to such a high price is because of those dedicated adaptors and accessories. Some premium brands charge a lot for them (e.g. a Tak flattener could be as much as a 4" ED doublet). LZOS is probably the cheapest option in this regards as APM scopes are compatible with many generic adaptors and the Riccardi reducer/flatteners cost less than half of Tak or AP.

OK, so it's the outward travel in the focuser that you need based on your latest description. This should be easy to solve. If you've got the original 35mm extension tube, pop that in between the focuser and the mpcc.

If you did manage to get proper focus with this exact same setup, then my previous assumption was wrong. I thought you could obtain focus before and it was the new coma corrector (or spacers you use to get the correct spacing) that had pushed the camera further out and you could no longer get focus because the focuser ran out of inward travel. When you used your eyepiece to obtain focus, did you compare it to your imaging setup? Did you move the focuser further out or back in?

Sounds to me like you've run out inward travel on your focuser with your current imaging setup. The coma corrector, t-ring and the flange of the camera have taken up all the backfocus the scope provides.

Have you put your RPi in a metal case by any chance? The metal casing could seriously weaken the already weak stock WiFi signal (both broadcasting and reception) on the Pi.

Don't bother with anything less than a Pi4 if you are going to use astroberry for purposes other than a basic INDI server. I've tested it on Pi B+ (the same specs as Pi Zero), Pi 3A, Pi 3B+ and Pi 4B 4GB. PHD2 runs on Pi 3B+ and Pi 4B although the startup is a bit slow on 3B+. It refuses to start on B+. On 3A it starts up just like on 3B+, but would slow down to literally non-responsive after about 20 mins. Kstars/Ekos runs fine on 4B. It lags on 3B+ if PHD2 is running at the same time. On 3A and B+ it takes ages to start up and then brings the pi to its knee after about 5 minutes.

The Hercules is only used with the 72. Although its specs is rated for up to 10kg (I doubt), I don't trust it. My 107 goes on the iEXOS100 for night time use only.

Another vote for the BST. Alternatively you could pick up an 8-24mm zoom. As for the filters the only ones I'd recommend (also used by myself) are variable polarising filter (for the moon) and UHC (for certain types of DSOs in light polluted area).

You've got yourself a nice little setup, very portable. The skymax127 + az-gti is a very popular combo. Below are my answers to your questions: 1. Here is the T-ring for Nikon from FLO https://www.firstlightoptics.com/astro-essentials/t-rings.html. Don't worry about those low profile adaptors, just stick to the standard one. You will also need a 1.25" nosepiece https://www.firstlightoptics.com/adapters/astro-essentials-1-25-inch-t-mount-camera-nosepiece-adapter.html 2. BST starguiders are often recommended as a cost effective first upgrade to stock eyepieces https://www.firstlightoptics.com/bst-starguider-eyepieces.html. An 8mm + 15mm along with the stock 25mm will cover a broad range of useful mag. Alternatively you could pick up a 8 - 24mm or 7 - 21mm zoom. 3. For eyepiece projection type of photography, there are aftermarket adapters for both DSLRs and phones https://www.firstlightoptics.com/adapters/universal-camera-adaptor-for-eyepiece-projection-astrophotography.html. You could also get Baader Morpheus or Hyperion eyepieces for this as they have the necessary threads built in. I've never tried terrestrial photography with anything other than a refractor, but I suppose the principle is the same with a Mak. Keep in mind that Maks are quite slow by imaging standards (big f ratio), so they are only good for stationary targets.

The protruding bolts beneath the dovetail bar are anti-sliding safety measures. Your best bet is get a longer dovetail bar.

25 pixels dithering in your imaging scale should be enough for DSLRs afaik. My settings in BYEOS and PHD2 result in about 20 pixels dithering with my guiding to imaging ratio. I've read that Spiral dithering yields better results than Random for DSLRs, but personally I haven't noticed any difference. With my local light pollution level most of my subs are between 90 and 180 secs. And I usually dither every other frame in order to maximise the number of subs within a given time-frame. I only dither every frame if I'm using my triband filter on some nebulae targets and my subs are 4 - 5 mins long. My setup usually recovers from dithering within 25 to 30 secs (this includes the standard 10 sec calm down time in BYEOS). So if yours timed out after 180 sec, you may want to double check the balances and backlash in your mount.

A Core i5 and 6GB RAM are more than enough to run PHD2. If the laptop is unstable and you're not comfortable to do a full wipe yourself, just ask an IT friend or take it to a laptop shop to get it re-installed. ST-4 port guiding while useable is not what most of us use in our setup. To guide a Skywatcher mount with pulse guiding through USB/Serial, there are two methods: 1. The most common one involves EQMod and an EQDIR cable. The synscan handset is removed from this configuration. You will need to install the EQASCOM driver and the EQMod software suite on your laptop, then connect your NEQ6 to it with the EQDIR cable. There are many tutorials and videos on the web to help you operate the EQMod software and set it up with PHD2 for guiding. The EQDIR cable can be bought from FLO. 2. The less popular way (I've used it before personally and it worked very well actually) is to guide through the synscan handset with the firmware update cable. This cable is included in the original package. Instead of installing EQASCOM and EQMod, you will only need the standard ASCOM driver from Skywatcher directly. You can carry on using the directional keypad and even GOTO on the handset, or a planetarium software on your laptop to control the mount. PHD2 works the same as method 1.

Is your 70mm travel scope not good for terrestrial use? IMHO an 102mm f/7 is a little too big and clumsy for birds. But if you would like to give it a try, any of the push-to alt-az mounts would work. Personally I use a Hercules 2.5" alt-az (also sold by RVO and Artesky). Other good lightweight choices include mini Ercole and AZ4.

You will be pushing the limit of any of these three mounts you listed with an 80mm refractor. So either stick to 70mm or step up to EQ5 for the 80mm. My advice would be to get an HEQ5 and stick to your 130p for now. You will need a coma corrector for it. Then save up for a wide field refractor in the future.

I think you're right. They are probably trying to copy the marketing strategy of Stellavue and LZOS by offering minimum strehl. If they could fit these well figured lenses in a full steel lens cell like LZOS, then that £500 increase is certainly worth it.

I thought FPL55 was supposed to be more friendly to figure and polish, so theoretically it should be easier to achieve the desired min strehl than the FPL53 counterpart. Maybe the new 55 model has other improvements to warrant a £500 price increase.

ES stuff are all made by JOC (Jinghua Optics & Electronics Company) exclusively. Bresser and Meade are two other brands that sell many JOC manufactured products. I reckon this Opticstar is just another new partner of JOC, hence the XL82 lineup looks exactly the same as ES82. The price difference may be due to different minimum specs requested by each company (or simply market presence and brand recognition). This is quite similar to products sold by TS Optics, Altair, AT, Tecnosky and WO. These brands all source their stuff from the same few factories in China and Taiwan, but offer them at different prices.

Wouldn't an 102mm doublet be a better choice for visual on the Moon, planets and double stars? Being a triplet with dual EDs and designed more for imaging I'm pretty sure the CA is well controlled. But at native f/5.5 the field curvature is probably on the high side impacting wide field views. Also you will need to work with very short focal eyepieces for high mag. At 4.2kg it weighs about the same as most 102mm f/7 doublets. And in terms of OTA length it's only about 10cm shorter (468mm compared to 580mm of my APM 107 which is also manufactured by sharpstar). So it seems there isn't much gain for the portability.

That will be a "yes" for me if the quality of the zoom is up there with the mid to high end fixed focal eyepieces. Not only it will minimise the hassle of swapping eyepieces, but also be a huge cost saving compared to a set of high-end eyepieces. It would pretty much kill off any expensive 60 - 76deg short to medium focal length eyepieces (e.g. Morpheus, XW, Delos, Delite, etc.) I suppose.

Try "sudo apt-get install python-rpi.gpio" for python2 or "python3-rpi.gpio" for python3. You could also use pip to install the latest development version of the RPi.GPIO.