AlexK

The RDF/Telrad sole idea is in the largely unobstructed straight-through view of the sky provided, which allows you to place the pointing dot/reticle between stars you see naturally naked eye around your target. With most any right angle solution you are losing that benefit as the prism/mirror will shrink your field of view to a useless (for a beginner) key-hole size surrounded by the ground/OTA side background view. It might be especially confusing if the sky view is also mirrored. If the straight-through view is truly a pain for you (bad neck, back, sholder what have you) there are 3 drastic solutions: The GLP (green laser pointer). It's nice, but might trigger legal consequences in some regions. Also it's ruining your eyes darkness adaptation when observing from a dark site. Very tall collimation pointer (e.g. QuInsight). Or/and you can consider rising your telescope mount on a dedicated table, so you can point it with a straight-through RDF more comfortably (e.g. I've been using my Telrad on the SIDE of the OTA, under the EP focuser, for pointing my z12 "Bazooka style", standing on my knee(s), see photo, for like a decade prior to switching to the QuInsight). A digital assistant (e.g. CSSE - Celestron StarSense Explorer technology). http://fo.kukarin.com/storage/cache/images/000/069/20200428-193439,medium_large.1588127952.jpg (Weird. The updated forum doesn't automatically embed images into the post. ANyhow, on it I'm proofing to a skeptical "colleague" that I can point the unmodified 12" Dob "Bazooka Style" into the horizon comfortably ).

Totally logical when you have some education about the modern battery tech, a little bit about the modern "global" economy, and ever heard about the second oldest profession "marketing" (you know what's the first oldest one, which gave birth to that second, right? ). I.o.w., the DSLR camera batteries tech is not a high-tech anymore. It's reached its technological limits all the way to some ~90% profit like a decade+ ago. You are paying more for the HazMat shipment insurance than for the battery manufacturing expenses. Which means that OEM battery is the same as a nonOEM, the only difference is the higher probability of a manufacturing defect (and fraud). Which is mitigated the same way: Send it back and get a replacement, OEM or NoName.

Can't comment on your particular "brand", as you forgot to provide any links, and just generalized your experience. But I've got a bunch (6) of quite cheap noname batteries for my oldish EOS 600D like 4 years ago. They're still performing fantastic. To generalize: with the Amazon service, just watch for "free returns" widget on the right, and if you've got junk, just mail it back and try another piece.

Edmund Scientific Astroscan is an unbeatable instrument in that category. I'm taking mine even into carry-on only "expeditions". The most notable one being the Totality of 2012 in Australia, where I spent 6 nights with it on the top deck of the rocking in the South Pacific scuba diving boat anchored at the Great Barrier Reef discovering Southern sky goodies for the first time. Its ball mount is perfect on your laps when in the chair, recliner, or just on the grassy ground, as well as on your chest with the shoulders straps adjusted right when standing upright. Or you can throw a trivial plywood ring (or even some glass/aluminum jar) underneath and have it perfectly mounted on a table or on the ground beside your sleeping bag. When I've added the static eyepiece holder for my 100 deg AFOV eyepieces it became even more amazing in the hands due to the possibility to hang it lower on the chest for better stability: With 100 deg AFOV it's like having the starry sky everywhere: above and below you.

Thank you, Jonathan. The "windbreaker" is how we call here a windproof layer of clothes (usually the outmost, like a parka) which is eliminating air intake/escape. I have a zippered double front flap, wrist and hips constriction corded, nose high collar with hood rubberized shell, in which I can almost lay down into the strong wind. The most efficient piece to fight the cold for me is my long micro-fleece balaklava. OTOH, the cold and heat sensation is very individual, have you heard about the MIT developed device attached to your wrist and sending waves of heat and cold using a Peltier element and a microcontroller? It's effectively reducing or inhibiting these sensations in the entire body by command while touching your wrist on the inside only. What you are doing to setup with your bare hands is exactly what I'm suggesting to optimize. E.g. you can get/make a wheeled system to move your rig out pre-assembled. If absolutely impossible (which is doubtful). I can see all the metal parts modified to reduce the cold choke. E.g. adding plastic sleeves/handles, also I have a can of spray rubber and can see covering the mount/OTA in strategic places not only to insulate it but also adding an ultimate grip (it's easy to remove later e.g. if the plan is to resale, though if you apply it in a quality way, using spray masking it might even add the value. I have 3 electric blankets from China. All modern options are low voltage and very well made (I would say even overprotective).

A hemispheric dome shape is used to minimize the material it is built from to reduce the weight as you want to move it around rather easily (by hands in the distant past). The OP idea looks like just a round shed with the removable roof, not really a dome. So for a shed, there might be cheaper and more practical and convenient options (e.g. a ready to use plastic garden storage shed, just don't attach the roof completely). Migt be cheaper as well (surely, unless you can find a used/broken/defective tank, though a used one might be smelly ) For the actual rotating dome-like roof, the easiest to make and most useful for our purposes approximation of a sphere is the rhombicuboctahedron: I know it built from wood pieces and from welded metal scraps. It's easy to cover the surface for waterproofness with wood, metal, or most any other sheet roofing solutions, as well as equipped with sliding or hinged doors opening a large slit window from horizon to zenith (just cut or remove 3 squares). Just my 2 cents.

Not sure it's allowed to give a feedback on this "sad" thread (I seem to be ruining the other "happy" thread doing that recently ). Just let me know. But I used to observe in -30C winters in Siberia and know what that entails very well. So: Refuel. Get a decent piece of high calorie long burning meal (e.g. prior to all day diving in the Pacific I'm taking a serious chunk of well done ribeye with spaghetti for the brunch on the way to the diveshop). That would give you 3-4 hours of good inner heat source. For the short boost a sip of hot chocolate with milk from my 0.75L thermos saved many cold observing nights for me. Warm up. That means obvious vigorous exercises (like sit-ups, or see here) for about 15 minutes prior to going out to boost your natural "heat distribution hydraulics" and the "engine". Run the "engine" periodically at the scope as well (I do every hour). Keep that heat for yourself. Think about your clothing out of the box. Your body must be insulated much better than for a regular winter walk as you are barely moving at the telescope. However, that might interfere with the 2 above, so the alternative option is (4): Add an artificial source of heat. E.g. an electric blanket wrapped around the body (there are 12V versions available too), chemical heating pads (that's what I have in my outdoors kit, reusable salt crystallization based, just for high altitude cold occasions, the large shoulder one runs for 3-4 hours). The only issue is that if the excess heat escapes uncontrollably it may affect your views if the hot stream of air intersects the light path (which is often the case for a typical Dob). So a windbreaker is a must (even without an artificial heater). You can always open it up to release the excess quickly if feeling really toasted. Reconsider your instrumentation. I saw a nice thread around here about gloves. I'm using fingertip-less gloves with the magnetic flip mitten pocket. Trust me that's the ultimate solution (given 1 and 2). However if your observing flow requires you to do something often with your bare hands, better start thinking how to eliminate that. All of the above is very rewarding, as below 0C winter nights are commonly reported as clearer, steadier, and longer nights compared to warm summer nights.

I can't see Napa Valley hills from my 55 yards observing tower (50km distance). So the visibility is poor for planets while DSOs are not worth it in 10km vicinity from San Francisco downtown, the Moon is already high as well, and there are no "urgent events" in the sky either, so the scope stays put, but as it's warm and sunny I'd rather go surfing

Yup. A MAK is very universal, has a good repurpose and resale value, and that AZ-GTi mount is quite a decent piece on its own and also highly re-*. So it's for any further hobby development in multiple directions with the wow-factor (a conversational piece at any outdoors party) persisting in both I'm still keeping my 20 y/o ETX-125. Perhaps, it's time to re-seat it to AZ-GTi... (Added the "Sky Watcher" to my list above)

I'm with Louis. if the birthday is close, you might be out of luck. Just checked the Amazon and they don't have anything decent in stock in the $500-$1000 range. Just some China semi-garbage. I bet speciality shops are the same. So if I would be in your shoes today (my wife gave me a telescope for the birthday too some 20 years ago, it was very romantic ) I would just look on the websites Louis has mentioned above for a most expensive piece with "Orion", "Celestron", "Meade", "Sky Watcher" in the name and either with Dob/Dobson word in the name or with the tripod visible on the image. These brand names are simply easier to resale later and usually not a garbage in that price range. I would feel much better if that will be one of these gifted than some "Theseus". I think that a viable alternative to otherwise learning the astronomy and optics from a scratch yourself Just checked the Agena Astro (love them). This is the only thing they have in stock which I would consder as a jiga-dance gift for a casual beginner: https://agenaastro.com/sky-watcher-skymax-127-mak-cas-telescope-az-gti-mount-s21130.html (The last one though, so be aware that someone may snatch it as we speak).

Which "way"? I'm just explaining to Alan how the high-tech market works. My initial point was that a high priced sophisticated looking (PCB with "microchips"? Wow!) piece of electronics does not necessarily means the best solution you can apply to a specific problem if at all. "Cheap" means "Very easy to manufacture all the way to having a bucket of these for just a buck" mostly because of the mass production scalability (these circuits are printed, including with the "resistors ink" in about 1 minute per PCB). Alan has missed the point obviously, so I felt a bit of explanation is in order. No offence. Sorry for grounding this "Happy thread" a little bit I believe that hobby forums like this great forum are to "ask before buying or building" as our hobby is not cheap. While the underlying knowledge is rather scarce, which is leveraged by "marketing gurus" all the time.

The company in UK doesn't mean they employ a local PCB factory as that would mean the price of that board will sky rocket to around $100 retail to maintain the profitability. At max they are soldering wires and that's it. I can right now draw that (or frankly anything) PCB in CAD with resistors populated and email it to China along with a $40 check. Within a month (OK, two, due to COVID) they will send me back a dozen or two of ready to sell pieces neatly individually packaged in the box. I just need to advertise it available from a UK seller to hook you

Mine is too, so I do just this: And that's a full OTA 12" Dob: Which is stored at home simply standing upside down in the rather shallow wall wardrobe. Just a little investment into a DIY transporting system. Plenty of really decent advice above. My 2 cents is: wherever you end up on your search, a 150mm aperture is about what should be considered the starting point for truly rewarding planetary views with a reflector. So I'd stick to that as a bottom plank.

Guess, fair enough. Just paint it black with a sharpie maybe? That ghosting might compromise the performance (not necessarily for the similar Rigel heater, as it's on the opposite side of the mirror).

I'm always been puzzled why folks are resorting to these complicated to fit china cheap circuits for heating while a short piece of proper size NiChrome wire would do the trick much better, e.g. using the Telrad's own battery pack, and without obscuring the view and without ghosting reflections? Just for sophisticated looks?

And that prob. explains why your mount so tall compared to the classic barn door, which is essentially just two plates doing "a closed door slowly opening to the West" By the way, the Astrobits' confusion about the platform closeup above is due to the Azimuth Polar Alignment center axis is projecting to the hinge base piece behind it, creating an illusion it's a single module.

Thank you, Chriske, for the interesting story behind that design. I thought that's just the ordinary Barn Door tracker, which is known from 1975: https://en.wikipedia.org/wiki/Barn_door_tracker (I built one being a kid in 1979 to track the Moon with my DIY electrophotometer during a winter eclipse. The idea to use it for Telescope tracking never crossed my mind until recently (~2010), as prior to my beloved z12 I had motorized GEMs exclusively all the way to a 150mm Newt. By the way, do you have a thread on this forum about your more recent Boxmount advancements? Or I should just search the CN?

Wow! I have simply pasted the Image URL from Google images search, when by an accident saw that platform image among other findings, as I recall liking the idea some year back and wanted to demonstrate the barn door principle difference from a poncet. But I'm not sure where exactly I saw it for the first time (most likely on the CN forum indeed). And that was not that exact CAD drawing. I saw it made in crude wood with the additional pneumatic lift arm assist system. So, if it was yours, all the due credits going to you, Chriske! Please, let me know how I should attribute the image in my post above, remove or replace it with a more suitable one. I'll edit the post right away if I still can. Neil, thank you so much for looking into that closely! I'm a total dummy in EU/UK law differences vs US in regards of such incidents.

That's a nice feature indeed. But you need an ordinary printer too. I'm trying to get away from paper as much as I could The imaging is a huge subject on its own indeed. But even a mediocre EQ platform would allow quite decent planetary and moon images possible (they are all shot in the video mode, then each frame is stacked. You will be amazed how much details an ordinary deconvolution algorithm could retrieve from a few dozens of thousands frames with a smudgy blob dancing around

Sounds good! 👍 One last tip for now then: One of the tasks on a "compound" project like this (wood, metal, 3DP parts) is aligning the stuff together. For 3DP parts, you can print additional features dedicated for that. From trivial center/middlepoint markers/pilot holes all the way to long "rulers" which you align together before screwing parts down to the ply. Even a kid could do a nice assembling job with such visual aids.

10s is actually a decent exposure. Have you heard about stacking? Just a dozen of 10s exposures through the tiny aperture of my smartphone (Galaxy S8) reveal 9.5m stars already when stacked. With your 150mm Heritage you can do decent enough DSOs, but for that your tracking must be decent as well, as even the smallish Heritage has a significant magnification. Not sure what you mean no accurate polar alignment required. You have to have it provided quite well on any EQ mount as even if you could adjust the tracking speed on the fly and even add the second motor to compensate for the declination error, you will need the third motor to compensate for the field rotation which might be an issue even at a 10 seconds exposure, and especially if using the smartphone in EP camera setup. Nothing drastic, though, just pointing the true rotation axis to the Polaris would suffice.

The rod should be metal, you want to print the rack (worm cog sector), which is much easier as you can print it on the side (most recommended for the threads but often needs supports if your parts fan is weak. Definitely a stronger filament will be needed, I would use nylon.

That's another manual control prone to errors... But OK. Perhaps, use the end switch then and after moving the slider manually, command the controller to rewind to the "zero" (same as on printers). That would give it a more reproducible starting position.

By the way, just checked my printer rods, they seem to be OK for the wormgear, you just need to find or create the proper cog profile for their thread. I think, it's called the pipe or tubing thread. Correction: I's called ACME thread (though I see different threads might be used in 3D printers, so check your's to be sure), which is very close to the worm thread. The latter is a bit deeper (0.69P vs 0.5P). If not, a 1/4"x20 steel rod with the standard Sharp V (which is even taller than Worm) is like $1 per foot at any hardware store.

I'm MS in EE and MS in CS, that's why the worm gear and cam's advantage is so clear to me They are doing the perfect job just passively thus cannot mishap as any EE/CS solution could eventually. But OK. Let's brainstorm it a bit too. How do you plan to tell the controller what speed to use at any given moment, especially if you can move the slider back or forward manually any moment?