discardedastro

I've had a TG365 cover over my newt for a year and a half now. Definitely seeing some moisture issues - there's some visible rusting on the counterweights, for one. I took my dust cap off the guidescope last night to find a bit of white material I think was some sort of growth but might've been a little spider's nest - took the scope off and cleaned it today and it's all fine. When I took the cap off the main scope the main mirror was sitting with a light coating of dew on it. The electronics all seem entirely fine and after 5 minutes sat in the sun the tube was dry inside and out. Hadn't considered intermittent heating but it does sound like a good way to help protect against this stuff. I have a plastic cover on the back of my OTA to protect from stray light and I was thinking about putting in some silica gel between the mirror back and the cover, but the heater would be neater. I haven't got permanent power outside just yet (I keep holding off for the "proper" solution of an observatory with a dehumidifier) so a battery/solar would be my only option (unless I go sort that); might have a think about a sensible way to control some heater strips based on measured RH and temperature...

Looks good. For the sides where you need more compression we use brush strips around our air conditioning pods/cold aisles at work to keep the cold air from leaking out around doors etc - they're very low friction and deform easily enough but are good at minimising airflow. I imagine they'd keep flies and other lightweight wildlife out, though not mice etc.

If you are looking for a cheap laptop then the Motile (Walmart's own brand) M142 is worth a look at $350ish - eg https://www.newegg.com/p/1TS-00AF-00006 It's got plenty of I/O, full HD screen (1080p) and you can upgrade both RAM and storage easily (NVMe, so fast storage at that). The AMD 3500 is a great part. I'll definitely +1 the Raspberry Pi 4 approach though. I have one which lives on the telescope tube (under a Telegizmos 365 cover) attached with adhesive velcro in a Maplins project box, holes cut for USB etc. Just make sure you run Ethernet in, WiFi will let you down!

Ahh, that makes more sense! I couldn't see the MPCC ring in the photo but yes you can remove that and insert it further. Not a bad idea to get some more backfocus! With the Clicklock you'll just need to make sure it's actually gripping on the CC rather than on the spacer, as otherwise you might not end up with the kit held straight in the focuser. The Clicklock will do a great job of bringing things on-axis consistently if you've got it gripping onto the CC - I don't think it'd make good contact on the spacer.

Ah, no coma corrector? If you get a Paracorr they have a modest Barlow effect to push the backfocus out - but more affordable ones won't, so you lose some travel to that. With a Clicklock on the Baader diamond steeltrack and a MPCC Mk3, EFW and CMOS (ASI183MM) I had about 10mm of inward travel left.

For me it's the last complex step in the train where I've done nothing drastic to the image data. StarAlign is a 10-second job to repeat, so if I needed to, say, paint over some satellite trails or wanted to use the frames in a mosaic I've got everything "ready to go" and then re-stacking is trivial. I also use the timestamp format, just ISO 8601: YYYY-MM-DD. If it's an event or not my usual imaging rig I'll append a name or similar. Then projects for specific targets get a YYYY-MM <target name> folder, etc.

I keep everything off the camera as FITS, including calibration files, and normally keep the calibrated but not registered XISF files from PI, plus LRGB master files before any processing, cropping etc. That way I can easily re-create the stacks without doing recalibration, repeating cosmetic calibration, etc, or just combine the stacks from a few nights. If I need to go back to the source, it's all there. Storage is cheap! Only a quarter terabyte so far on the raw datasets, covering a year or two, and I have about a terabyte for all the rest including some stuff like videos from eclipse events etc. I keep most stuff on a ~30TB usable ZFS array I use for all my data storage needs - it isn't fast enough for working storage (just SAS2, and networked at a gig, all spinning disks with NVMe L2ARC/logs) so I copy what I'm working on to a 2TB internal NVMe disk at the start of processing. Edit: Oh, and for backups, I use Backblaze for everything stored on the PC which retains for >1 year, so that's something. I am planning to spin up some more storage soon and I'll do backups of the raw content to that regularly. Backblaze is great, but does require a fast upstream internet connection - I've got a gig a second up, so it's not a problem. The raws are stored on a ZFS array which can lose about 3 disks before I start worrying about data loss, so it's pretty resilient.

I think on the 250 you'd struggle with backfocus. I upgraded my 200PDS focuser to a Baader Steeltrak Diamond and it's night and day - well worth the investment. But I also got a Clicklock clamp with it, which does work, but takes up a lot of backfocus so my "focus in" remaining at prime focus was very minimal. Fine for imaging but not great for observing, so I ended up swapping back to the supplied clamping ring w/ three screws. The Clicklocks are good and would probably be awesome on an SCT/Frac with tons of backfocus to play with. I spent quite a bit of time trying to make the Skywatcher dual-speed focuser "better" but fundamentally it's pretty much as good as you're likely to get out of it because of the materials, construction methods etc. The Baader focuser is about 1.5 times the weight and has completely different feel to what I was able to achieve with the SW one. Common "mod" suggestions are to really flatten the friction plate on the drawtube and replacing the bearings but for my money I'd just save and invest in a replacement.

Electromagnetic Field, aka emfcamp, is happening again this year. For those not aware it's a hacker/maker/geeks camping festival held over three days at Eastnor Deer Park near Ledbury. https://www.emfcamp.org/ From the site: "Electromagnetic Field is a non-profit UK camping festival for those with an inquisitive mind or an interest in making things: hackers, artists, geeks, crafters, scientists, and engineers." There's lots of talks, events, activities, and mad people (and a bar, mains power and Ethernet to every tent that wants it, and WiFi across the site). It's a great event - tickets are on sale from Feb and spaces are limited to a few thousand. I'd really recommend it, and imagine plenty of people on the forum would find it of interest! If anyone's interested in going, last emfcamp I took my telescope along - didn't achieve much success as I wasn't kitted out for solar and overnight it was cloudy as anything (plus the site is pretty lit up in places, with lasers and smoke machines as well as normal lighting, making faint observations tricky; the organisers have suggested a pretty good spot on the site which will be kept dark, though). However this year I'm intending to go with a solar rig (once I figure out how to put one together) and a few other bits so I can do some demos/outreach. "Unfortunately" it looks like we'll have a moonless night with no planets, so "interesting targets" will be an interesting challenge! Anyone else interested?

Starlink's about the right time - ish - but not in the right place. I think that's BEIDOU-3 M24.

Probably Starlink-2, a train of new telecommunications satellites. The timing fits. https://me.cmdr2.org/starlink/

Literally my first attempt to shoot and process a comet - on my usual rig, so a 200mm f/5 Newt w/ ASI183MM. Tracked using the details from the Minor Planets Centre fed into PHD2 using KStars/Ekos/INDI on an EQ6-R Pro. Processed using StarAlignment/CometAlignment/ImageIntegration/DBE in PixInsight - don't have calibration data that's current so just straight off the FITS w/o dark/flats. 10x300s exposures, Baader luminance filter.

Interesting. Hadn't considered that on my build - haven't dug it yet so time yet to ponder! Was planning for a 800x800x1000 cube but my site is about 10 metres and probably less than a metre in elevation from a drainage ditch - it's what I've got to work with. Wonder if a more shallow but wider base might be more sensible. The 1 cubic metre volume I think is about right - probably slightly excessive but definitely enough to resist any forces on the pier. It's also the smallest volume any premix truck will do you, so 🙂 Would definitely aim for C20 or better spec-wise, either way, ideally C30.

Just to add to this I've been using Ekos+PHD2 for quite a while without issue. The PHD2 setup in the Ekos rig is really straightforward - just enable the server, switch the guider to PHD2 in the Ekos profile, and hit connect in the guide tab - there a few edge cases where it can get confused but restarting PHD2 rapidly fixes those and most nights it's trouble-free. I would say that PHD2's guiding engine seems to do much better than Ekos', but given the relative volumes of effort into each perhaps unsurprising. If you're using indi_eqmod then just using pulse guiding via that will work great and is definitely the easiest setup to deal with.

If you've got a Goto 'scope then you can show position and write down the RA/Dec figures. Otherwise you can take a smartphone camera with a cheap adapter - which should give you enough stars to plate solve - and get RA/Dec off of that. Astrometry.net can do plate solving for you online.

Do you mean fitting into the saddle (i.e. the clamp on the mount that holds the dovetail which your tube rings mount to) or on top of your tube rings? If the latter, length is the critical factor as it needs to be long enough to cover both tube rings (or you'll only get one screw for mounting, which is no good). "Vixen style" and "Losmandy style" are the two widths/profiles you'll find for dovetails, and most (large-ish) SW mounts are dual Los/Vixen saddles. But what you've got there is a clamp for Vixen style rather than a dovetail in and of itself - so you could mount that (if long enough) either onto the tube rings and then clamp a Vixen-dovetailed component on top. Or you could mount it on another slotted dovetail using some suitable nuts/bolts. It might be easier if you explain what you want to achieve?

The top thread for a camera is a 1/4" Whitworth (yep, really) thread. I don't know what the SW top plate is threaded but I think it's a standard metric thread (or imperial, what with the US market still existing, sadly). But searching along those lines should yield something. 1/4"-20 UNC thread will also work, though the official standard is Whitworth.

Getting a solar telescope rig sorted would be nice, as well as a visual rig I can use while the imaging rig is doing its thing. Observatory is probably the priority this year though. Would love a dome, but a roll-off feels more practical and I'd be able to put a few scopes in rather than just the one - we shall see.

Not sure it drifts that much but I definitely have to re-do polar alignment on at least a per-week basis. I suspect this is more about the gardener bumping into the tripod than anything else, though, but it could be the mechanics aren't that great in terms of stability. The coarse threads probably do permit a bit of slippage.

Sadly the Z6 is work's, so I don't have it set up just so - it's a bit of faff to get it worked into AP mode, but fine once it's there. This was on the 24mm end - I tried 30s but had definite blurring, 5s was alright but I should've gone for 800 ISO rather than 320 as I understand that's the max native gain of the sensor. It's a heck of a lot less noisy than my Nikon D1x, but no huge surprise there, with 18 years between them! That the lenses all still work is something of an engineering marvel. Once the prices come down a bit I'll definitely be nabbing one myself - the only complaint I have is that the tripod plate I have is too big to let the FTZ adaptor move past it, and so you constantly have to swap the plate between FTZ adaptor and Z6 base if swapping between F and Z mount lenses (which, inevitably, I do). I'll take a look at Sequator - feels like there should be a nicer way to do this in PixInsight...

I use AC power from some external sockets. It's perfectly safe, so long as you throw an RCD on the garage end - if there's any shorting it'll trip and revert to safe. I've never had an RCD trip and there's no significant safety issues with mains and dew, but use sealed boxes to house the exterior connection from mains to your 12V supply of choice (I use a Nevada one) if you're paranoid. As for 12V batteries, I've got a Halfords leisure battery which should do fine - I use it for camping but wanted something that'd work for the odd dark skies trip to the middle of nowhere. I'll throw some M6 terminals on and hard-wire my DC barrel jack lead which feeds everything but the mount and a cigar lighter socket for the mount. The other thing I need is 230V for my inverter to charge the laptop, so that'll just get connected directly also.

I've never done any widefield before but I had a Nikon Z6 to hand last night and it was beautifully clear, so I took ~25 untracked 5 second exposures looking back over my house. f/4, 24mm (using Nikkor's Z6 24-70mm FX Z-mount lens) The image came out better than I'd hoped, though in getting rid of the worst of the skyglow I also lost some of the brightness of the milky way. I'm still quite happy with how it came out. Processed with PixInsight - calibrated with dark and bias, debayered, aligned, integrated and CFA drizzled at 1x scale, DBE, BN, PCC, MLT denoise, TGVDenoised, histogrammed, colour sat and curves to finish. Bonus - non-colour-corrected drizzled integrated master:

I'd avoid point to point wireless unless you reach for slightly more mature/well-known brands. Ubiquiti do good things, like https://linitx.com/product/ubiquiti-airmax-nanobeam-ac-network-bridge-19dbi-gen2-nbe-5ac-gen2/15056 - these are inexpensive but reliable. However, PtP wireless is always going to be worse than Ethernet for reliability. Avoid TeamViewer and friends in all circumstances - they've had major security breaches. If you're running locally, you can use VNC to remotely control a PC - TigerVNC (free, open source) works very well, or Remote Desktop if you're using Windows. For file transfers, standard Windows file sharing (Samba on Linux) also works well. If you need remote access, then I'd always recommend using a VPN on a router to let you remotely connect, same way many corporate VPNs work. It's secure, can be done with off-the-shelf routers (though not your PC World fare - again, Ubiquiti have good options for that). I'm not a religious person, but Powerline is the tool of the Devil and should be avoided at all costs. It turns your otherwise-perfectly-polite 50Hz mains AC wiring into a fantastic broad-band noise generator which will [removed word] off (rightly) every amateur radio operator, radio astronomer, and radio engineer in a 10 mile radius. And it still won't work very well at all. Powerline is plagued by reliability issues, hugely dependent on how your house is wired (and the construction of that wiring - cable inductance, topology, etc), and will generally achieve very poor speeds even in pretty good conditions. Cables are always preferable and if you're getting someone to put in mains and duct, just buy the fibre/Ethernet and lay it in at the same time (along with a draw rope!). The cost is trivial compared to the headaches!

Need to be careful with the terminology here, because cat5 and cat5e are theoretically not the same (the standards are different), though anything sold as cat5 these days is almost certainly cat5e anyhow. My understanding is that cat5e is good for gigabit ethernet at cable lengths up to 100m otherwise it doesn't conform to the cat5e standard (though I'm aware that some people suggest you don't try to run them that far and I'd be tempted to use fibre over that sort of distance myself). In some situations auto-negotiating interfaces will drop down to 100Mb/s (perhaps if the cabling run is longer than 100m and thus can't support the signalling rates required for gigabit ethernet or if the cable is damaged). If you want 10Gb/s then you do need cat6 (or cat6a for runs longer than about 50m). I have cat5e cable runs in the house that get up to more than 40m and carry gigabit ethernet quite happily. As someone who does telecoms standards for a living, you're about right! 5e is good for 100M, but only if it is a straight 100M link directly into equipment at each end. The second you introduce patch cords, you introduce loss - Ethernet is just radio, so if you're familiar with the concept of loss in cabling for satellite/ham radio then it's the same principles. Connectors == Loss. So sticking a switch straight on the end at each end is fine (since the switch "ends" the 1G-BASET physical signalling segment, or PHY, and creates new ones for the other connectors). The 100M number also relies on perfect install - no damage to the cable through excessive bending, torsion or tension. Over 100M in ducting, things like tension start to come into play, and without using things like swivelling pulling socks you can introduce torsion easily and damage things. That's not something fibre's immune to, either. 5 won't do a gig except at short lengths. 5e (what most stuff you'll buy in Currys/Amazon will be) will do a gig to 100M in theory and 70M in typicalpractice. 6 will do 100M in practice, but 10G in theory. Fibre will do kilometres without breaking a sweat at 1G, 10G or 100G (if your optics budget extends to it). In all cases, the PHY layer will negotiate the fastest rate it can. Sometimes, this negotiation ends higher than it should - so you might get a gigabit link negotiated but only be able to push 500Mbps before you start seeing CRC errors, frame loss etc. The only way to validate the installed performance of a cable is with a certifier (which is basically a specialised test source/spectrum analyser - again, this copper stuff is all basically radios) or a transmission tester (which will just try shoving data around and see how it goes). Both bits of kit are very expensive, sadly, so most people (even a lot of professionals) don't do it - £1-2k will get you a transmission tester, £10k is entry level for certifiers. However, you can do a transmission test yourself with a PC at each end and iperf3 between the two. Fibre is a different beast but the same principles apply. If you didn't break it during install over that distance using singlemode you'll be fine - either it'll work or not at all. The margin for soft faults is pretty tiny, and over 100M I've seen live circuits working over horrendously broken fibres!

So - 100M, you want to do as Cat6, and 6A if you're doing this in the same duct as mains. Cat5 I wouldn't even consider at that distance - it will do 1G at 100M but only if installed perfectly - plus you'll always want a bit of slack, patch cords, etc so it's not really 100M. As posters above have alluded to, Ethernet won't get lossy (no matter how much audiophiles claim it's worth spending £100 on low-loss Ethernet patch cords) but will simply fail to negotiate higher speeds. Modern PCs will all speak gigabit Ethernet, so you really want to aim for that - it's a massive time saver vs 100M for typical large astrophotography datasets. The only other option I'd consider would be single mode fibre - this is a tiny bit more expensive but you can get this pre-made with ends on (the hard bit) from places like fs.com, e.g. https://www.fs.com/uk/products/29606.html - this is 100% futureproof and will let you run 1 or 10G, but it has the other huge benefit that it won't interact with power cables at all, and won't introduce any grounding issues, so will be much more reliable and simplify your wiring/grounding schemes. You use a media converter on each end (something like https://www.amazon.co.uk/ipolex-Transceiver-10-1000Base-Tx-1000Base-LX-Single-Mode/dp/B078RMXPGX/ref=sr_1_6?keywords=media+converter+fibre+single+mode&qid=1574981101&sr=8-6) to turn it back into copper Ethernet, so none of your kit needs to use fibre. Echoing the comments above, duct duct duct - there is absolutely no reason not to other than cost, but it's well worth it. We use 20mm semi-rigid corrugated conduit at work for small cables and it works great for single cables but you can get 54mm rigid "telecoms duct" cheaply eg https://www.drainagepipe.co.uk/telecoms-ducting-c-266/ which is good for mains plus some friends, without being huge and therefore expensive.