discardedastro

That's fair! 🙂 the NUCs are great little boxes. You can get Mini-ITX format machines which will take 12V as their input and run Windows but a bit more work.

It'll be a buck-boost converter. I'd stick to switched-mode supplies fed from mains if you've got mains handy - it'll be cleaner output for the PC - but decent quality buck-boost converters with plenty of output capacitance definitely exist. That or use a Raspberry Pi or similar 5V PC if you're using a Linux stack like KStars/Ekos - not so handy if you need Windows on the pier/scope though, but 5V is much easier to produce well than 20V!

Over short runs you'll be fine - if you want to be paranoid use Cat6A and attach the screen to a good ground, or use fibre and media converters. Practically speaking on 20-30m it's not going to be an issue. 6 versus 5e won't make any difference - 5e and 6 are identically shielded/screened, and 6A is too for the purposes of your install. Fibre and media converters is definitely the best answer because there's no metallic path to the house, but adds £80 in bits quite easily. At 30-50m you can just buy off-the-shelf patch cables, though, so actually quite cheap overall - a 30m duplex LC singlemode cable is only going to set you back £10, transceivers £5 an end, and some cheap converter boxes that connect your Ethernet cable to a fibre transceiver can be had for <£40 an end. Don't do Powerline 🙂 you'll annoy every ham radio enthusiast in a mile if nothing else. Depth-wise, I'd aim for >30cm depth. If you're doing conduit (and you should) then use something with a smooth interior and seal it once you've laid the cables and a draw rope in to prevent water ingress (Filoseal or similar gunk that's re-enterable - silicone sealant may do in a pinch, sand the conduit interior for adhesion). At 20-30m I'd go for a reasonably chunky mains cable to make sure you can pull 10-16A with little voltage drop - that'll cover you for practically everything quite comfortably. 30A at 12V is circa 2A at 230V, so would give you plenty of headroom for dehumidifiers, motors etc and ensure your input voltages for 230V kit stays nice and high. 6mm2 should be plenty but 2.5mm2 would be okay in a pinch. UPS is definitely a good plan regardless of how you get power into the site - don't forget your UPS will need enough current to recharge while also running all your kit after powercuts, so dimension your incoming supply 50% above your baseline. If you're not certain on waterproofing of the site then a covered plastic box with holes cut in the side or commercial options like the Dribox series would do well for keeping everything dry - they have some big ones which will fit something like an Eaton Ellipse or similar.

That's quite a lot - likely the mount is being pushed around or moved if there's that much error between sessions. I don't use Astroberry but in KStars/Ekos I start all my sessions by wiping the alignment data after unpark and a quick focus if required, and then running the Ekos mount model tool which will point the scope at 8 or so (configurable) different areas of the sky and give you a great basis for future alignment calculations. Only takes a few minutes and sets everything up pretty well regardless of the intervening conditions. I do find that - especially since I slacken my clutch bolts a little once I'm done for a night - the wind will tend to push my mount around a bit under its cover, so parking won't guarantee a repeatable alignment that's worth considering, so just starting from scratch each night is easier. Within an observatory, parking for the purposes of maintaining alignment is probably viable.

Ah, that's my lazy dumping of the Telegizmos cover it usually hides under 🙂

I'll be honest - I forgot to do it till the end! I normally do it immediately post-DBE on my RGB master prior to delinearisation for LRGBCombination. Having said that, it worked just fine on non-linear data. Looking with slightly less inebriated eyes, you're right on the green cast - and an SCNR has indeed tidied that up.

My "best frame" from this attached, in FITS and JPEG. Quite happy with how the Paracorr is performing, though still need to fix a tiny bit of tilt (adapter on the way!) M_81_Light_Lum_120_secs_2020-12-24T23-05-11_034_c_cc_a.fit

OK, so, this was entirely processed under the influence of Wild Turkey (only fitting given the season) Old Fashioned, so may be of variable quality! I think I did everything right in PI, but who knows. Most of the capture time was also spent somewhat inebriated. Christmas on your own is super fun! Taken from two nights of data this month, for a total 65x120s L and about 50x120s RGB. All taken on my usual rig; 200PDS on EQ6-R Pro, Baader Steeltrak w/ Sesto Senso for focusing, TeleVue Paracorr, ZWO OAG, ZWO Mini EFW w/ Baader LRGB filters, ASI174MM guide cam, ASI183MM-PRO imaging cam. Astrozap dew shield on the scope and Lacerta dew heater on the Paracorr. KStars and Ekos for acquisition. First night was calmer with better seeing, second night was a bit more windy so I discarded more frames due to wind. About 80% of frames ended up being used, weighted accordingly. Processing was reasonably straightforward and entirely within PixInsight manual end-to-end; calibrated w/ flat+dark, subframe selectored to ditch the frames most badly affected by wind, cosmetically corrected against dark and 6-sigma auto, stacked (with linear fitting and standard normalization, generally, but L stacked with 256-pixel Local Normalization), deconvolved (40 rounds of RL-R w/ 4 wavelet layers) using a dynamic fit PSF and local deringing, cropped, DBE'd, RGB was linearfitted before channel combination. L was MureDenoised, masks were used for MLT denoise on all background data before final stretching and LRGBCombination. Masked TGVDenoise to finish and some colour saturation to bump things up a bit. Lastly, photometric colour calibration and automatic background extraction to lose the last gradients. Not by any means my best but a pleasing result nonetheless I think!

True that reflector with dew shield will likely reject more stray light - I have a lot of internal flocking and baffling and a rear shield to keep it all relatively light-tight, but the focuser isn't immune to visibile light. However, with an appropriate IR-cut filter I would be surprised if there was any effect. I would wager that the IR LEDs in most cameras are quite "broadband", though, so it may not be completely cut by the filter. Neutral density filters generally will work just as well for IR/NIR as they do for visible, and you can get it cheap as chips in sheets from Amazon et al 🙂 so that'll knock down illuminator brightness quite easily. Alternatively, all you need is IR LEDs - you can just buy some and make your own illuminator/array. You probably wouldn't need many to make enough light, and could get a lot more control over the direction and intensity of illumination. That does have the benefit you can pick some nice narrow-band LEDs at a given wavelength, and make sure your filter will reject accordingly (if using one).

Use an IR cut filter on your imaging train and you won't have any issues, or at least I haven't noticed any. However, using a separate illuminator and switching off the IR LEDs within the camera(s) will give you more control and makes it less likely spiders will take up residence on that nice warm lens 🙂 PoE is definitely the way to go but take much care about sealing the incoming Ethernet connector. Splice tape/self-amalgamating tightly applied can work well. Water in there is going to make for instant corrosion at 48V. Avoid WiFi. Avoid battery cameras. Reolink, Dahua are both reputable brands. I'd avoid Hikvision over their connections to the Chinese government and their products specifically developed to perform racial profiling to "detect" Uighur muslims, but they aren't the only ones involved in that sort of nastiness. Avoid smart cameras and cloud services. Keep it local. Blue Iris is one of the better NVR platforms for Windows; there are options for Linux et al but nothing great (motion, zoneminder etc). This is from a Reolink RLC-420 camera (which keeps forgetting its configuration, so avoid that particular one maybe - their 410s I have a bunch of with no issues). While I'm in shot with a headtorch the IR is doing all the heavy lifting here. You will want more than one camera to see all the angles - one at 90 degrees to the other is a good plan.

To be blunt, speaking as someone with a good view of logistics in another industry that imports considerable stock from the far east and Europe, don't bet on anything showing up till July at the earliest. Normal service might start to resume sometime towards the end of 2021. We're working on the basis that Brexit will break most ports for at least 3-6mo while everyone figures out how to do the paperwork and the UK side builds all the infrastructure we're missing (the EU side has, broadly, got it all in place by now). Anything we needed to get in for our business, we got in months ago (and we have a new warehouse as a result). I'm sure FLO and others are doing their best but even non-EU imports are going to be heavily disrupted coming into the UK. Sea freight is already Interesting - we've had some shipments rerouted twice to different ports in hopes of capacity for the carrier - and air freight is far too expensive for astro stuff, by and large. To add to the Brexit fun, China is also swamped in a lot of its hub freight terminals, shipping PPE for COVID-19 all over the globe. We're still seeing major disruption at far east air and sea ports because of that, with month-long delays now common - it's so slow that it's actually been faster for some of our suppliers to expand their EU manufacturing facilities and produce items for us "locally". Lastly, some goods are affected by factory shutdowns and slowdowns due to COVID-19; this is probably the minority of causes of disruptions right now, but is absolutely still happening. Plenty of manufacturers - especially smaller outfits - don't have space to achieve social distancing in plants, or can only do it with a skeleton crew, so actual production throughput is pretty limited. China is doing quite well on this front but plenty of other places aren't. Sky-watcher in particular are probably OK on this front but products made in the EU or Americas are liable to be hit by this. By Nov-Dec '21 I'd anticipate vaccine deployment in EMEA to be progressing (though far from complete) and ports/hauliers/importers to have largely got on top of Brexit-related procedure changes and paperwork, as well as most of the Brexit-related backlog having caught up. So maybe early '22 we'll be "back to normal".

Draw-tube sag is possible but with a good focuser shoudn't be an issue. I'd try and measure things in terms of the output - either using CCDinspector or the FHWM plotter script in PixInsight - to see if you've got any significant tilt in the images you're getting out. Try a few different frames from different pointing positions to see if there's any significant variation with regards to attitude.

I don't get much in the way of vignetting but the small sensor in the ASI183MM-PRO is pretty tiny, so makes all that much easier. I calibrate with a sketch panel for flats. Main issue I have at the moment is vignetting from the pick-off prism - I need to tear the optical train apart again and add a spacer to get the rotational offset spot on so the prism lands on the wide edge of the sensor. From memory, you may want to increase to an oversized secondary for the 1600MM-Pro - the 200PDS if I recall correctly has a larger secondary than the 200P but some early versions had the same secondary.

What I would like - given I have a light cover on the back of the primary that provides a pretty good seal - would be to mount a big pile of silica gel in the tube when stored so it's at least starting out dry. Storing outside, it doesn't get a good continuous dry period very often, and with foggy nights the air trapped in the tube after sessions is laden with moisture...

Definitely not the best seeing, and just one night of data, but at least a nice dark night. 200PDS, Baader Steeltrak + Sesto Senso, ASI183MM-PRO for imaging and ASI174MM guide camera with the ZWO OAG for guiding. Paracorr corrector. ZWO Mini EFW filter with Baader LRGB set. 40xL, 40xR, 36xG, 30xB. Stacked all for a superluminance, deconvolved, usual histogram/saturation stuff, photometric calibration, LRGB combined, etc.

If you don't use a dew shield I'd start there - they're cheap and will also help reject stray light, so can't hurt! Reaching for heaters is the last resort imo. Secondary dewing is definitely possible, coma corrector is where I mostly pick up dew so a heater around the optical train can help...

Was going to suggest a cobra/fish tape - definitely the easy way to go, our installers use these and 20mm ribbed duct for fibre cables. Easiest way to pull stuff through awkward routes or high-friction ducts. I'll also throw in lubricant - something like Ideal 77 aka yellow gunk is fine and cheap as chips. You do need to be working in tension (i.e. pulling) but if you're a bit marginal on bends etc it can help considerably.

Having read through, I'm quite heartened by the proposals. But now they need to be spurred into action. This is the "write to your MP" stage of things - build awareness with your local MP and make sure that they support the govt actually taking action on the policy proposals outlined.

Sort of what I've done so far - the rig lives under a Telegizmos 365 cover and I can move it all around if I need to. But it can't wake up for those clear skies at 1am and put itself away again at 5am, and neither can I!

Oh, man, it's got to be the observatory to start with for my imaging. Everything else comes after. Fully-automated dome or roll-off obsy I want to "perfect" my Newtonian imaging setup - probably a carbon tube 300mm w/ some very good optics Something long-focal-length for planetary work would be lovely, thinking 400mm+ Dob or similar, plus a planetary camera/filter set Big 2"+ filter wheel and a matching set of Chroma/Astrodon 3nm filters for narrowband Just a nice simple visual observing setup but done well - something like a Rowan AZ mount and a 100mm Takahashi, few more TV eyepieces etc. And I'll be done by the time I retire, I reckon (and I'm not yet 30!)

Is this for imaging use or for visual use (i.e. motorfocus, so you can focus without so much vibration passed to the scope)? If the former, then the DC motor focusers like the low-cost Skywatcher one aren't a lot of use if you intend to use it with software that will perform auto-focusing because they have a lot of backlash in and are not repeatable. Autofocus algorithms all depend on being able to repeatably go back and forth to find the best focus point. For this, you practically need at minimum a stepper motor. Popular options would be things like the ZWO EAF, Primaluce Sesto Senso, and so on. Some of these may require a dual-speed focuser, which will also be much more accurate than a single speed focuser (using a 10x reduction gearing for fine focus). You can upgrade the 130EQ to a dual-speed focuser but are likely to find most of the upgrade options on that front will cost more than a similar replacement scope with a (cheap) dual-speed focuser included. If you're planning to do manual focusing with a Bahtinov mask or through something like Sharpcap to calculate HFR or other measures of focus, then the DC motors are okay, but you will find they have a lot of "slop".

Street cabinets - which are normally ventilated with plenty of airflow, and cooled by fans in summer - quite often have a 10 or even 50W heater in the bottom of battery areas (we normally have circa 150-390Ah in 4-8 12V batteries, so quite a large area) to keep things warm enough. You don't need much because you can basically dump the heat very directly into the battery and they tend to have good specific heat capacity and retain well. Spare dew heater strap on low would probably be more than enough - best to try it out with a temperature logger and see what it does first though, you may find you don't need it depending on climate. A pretty small gap would be all you need for ventilation, but you'll want something high up in the box for obvious reasons 🙂 a 10mm drill through the top would probably be enough, and something corresponding on the diagonal opposite corner near the bottom.

Do give it a little bit of ventilation - you don't want hydrogen build-up in your battery box! For really cold weather resistance, a little low-power heater in a reasonably shielded box will go a long way and won't pull much power.

With my telecoms hat on, we use this stuff to seal up any ducts entering structures: https://www.comtecdirect.co.uk/product/filoseal-duct-sealing-kits/PG5771 - street cabinets, underground chambers, and the like. It's re-enterable - you can cut it out with a knife pretty readily - but it's water and gas tight and will keep your duct ends sealed shut. So long as your elbows etc aren't leaking and the water level in the ground isn't too high then you'll never get standing water. Those seals will also work with flexible conduit to a degree though the seal will be less reliable if there's any motion. Installation takes about 5 minutes - it's literally a case of lightly sandpapering the duct/cables, shoving a (supplied) chunk of foam in to support the mastic, and squirting it in with a caulking gun. Then you use a wet sponge to smooth it over. The seals are also rodent-proof - a concern for some more rural observatory operators! For future builders, I'd strongly recommend solvent-welding PVC pipe bends and joints if you want them to be watertight - embedding in other stuff is a good second but chemically bonding the two halves together is unbeatable. Once you have the ducts sealed up, maybe consider a continuous dehumidifier for general removal of water from the ambient air? Edit: Picture of a (not-yet-set!) seal, just for an example from one of my test sites. It sets to a soft but firm solid.

If there's anything I've learned in my short time doing AP (a few years so far) it's that you'll never stop learning - but that won't stop you doing great things from the outset! I'd definitely recommend skimming through this thread for some good "lessons learned" on care and feeding of your shiny new mount...