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Been working on this motorised flap flat panel for quite some time already. Thought I'd finally post something about it as I just got the flap opening and closing properly for the first time. I initially designed this around the 28BYJ-48 stepper but that just turned out to be too weak. I did manage it to make it move by converting a 5V version to bipolar mode and driving it with 12V. But as soon as you removed power the gravity would take over and the flap would be a bit too flappy... Keeping the motor energised continuously would have made it too hot over time and it probably would have not lasted very long so I decided to go with a high torque servo instead. This one is using a Hiwonder LDX-227 servo. Seems plenty strong for this application. The flat panel itself is still work in progress. My original idea was to shine the light straight to the edges of the diffusing perspex but that didn't work out very well so I started experimenting with other ideas. At the moment the LED strip ring is hidden behind the diffusing perspex and reflecting off a reflector (aluminum foil on a concave surface). To the eye it looks pretty flat but if I take a photo of it and stretch the levels, you'll start to see a bit of a gradient. Whether this is a problem, I'm not sure... More about this later...

After a response from a few people, I am thinking of getting a alt-az mount w/slow-mo controls but the prices are very high, so can I make one at home? Also, the other reason is that the one I was looking at was suspicious looking like it could be displaced by a simple breeze, so can I make a slow-mo control mount or will it be an uncompleted dream?

While I've purchased and use various commercially available dew shields I decided to try my hand at making one, mainly for saving on weight for air travel. Quite pleased with the result. Only jabbed myself with the needle a couple of times. Hope.it helps if your thinking about making one.

I have stumbled upon a very interesting site, upon seeing their products I searched them on SGL, and they seems to have a good reputation, even FLO sells it! I am interested on many of there products, some will be asked in a other thread, so here are some of those questions: 1. Can I see details on the sun with this kit, if not can I see a solar eclipse safely without solar filter? (Link: https://astromedia.de/Der-Sonnen-Projektor) 2. Is this a good, useable telescope? I am going to observe widefield stuff with this! (Link: https://astromedia.de/Das-Newton-Spiegelteleskop) 3. This is a really stupid question, but can I project a bright space object (Such as star clusters) to a screen with this kit? (Link: https://astromedia.de/Das-Kleine-Galileo-Teleskop) 4. Can I create a eyepiece with these lens (specifically plossl's) Link: https://www.astromediashop.co.uk/Components.html, Look at the acrylic glass section) Other questions will be asked in a other thread, thanks for reading! Clear skies!

I bought two new dew heaters. They are sold to be used on camera lenses and powered from USB. I have modified them to reduce the power from 8 Watt to 2 Watt which will be enough for my demand. Some photos and documentation from this project: http://www.astrofriend.eu/astronomy/projects/project-heating-band/05-project-heating-band.html This will be battery operated and I try to reduce the power consumtion of the equipment. /Lars

Just a few days before Christmas, today I felt it was a good day to do something about my flat images. It has always been a problem. With color cameras there is a need to have the three color channels at the same signal level as the camera sensor see it. If not it can be that one color channel oversaturate and another one get too low and get noisy. I have used a monitor where I can adjust the color and other stuff, no one was easy to use. Now I building one with a RGB LED stripe with some extra control of the colors. Interesting ? You have photos and text about my DIY here: http://www.astrofriend.eu/astronomy/tutorials/tutorial-flatcalibration/07-tutorial-flatcalibration.html This is the one that worked best yet. But I have to develope it more now when I know I can use it. The 3D-printer will come in use again. Merry Chrstmas to all of you ! /Lars

So, as the title explains I need a mount for my 70mm F/10 refractor, It has a fork mount (Alt-az) and the tripod head fell with crash to the ground. So, it wobbles a lot and it causes frustration to even point at Jupiter, I don't want to throw It away, It is a nice scope and my first scope, so I need some easy mounts to make. There are some threads (Forums) but I would like to make a custom mount!

I am excited to join this big star gazing community! I realize I am abusing of your kindness, so that you in advance for any help you can give. I have an old telescope, what appears to be a Meade ETX 90 from the early 2000s. I cleaned it pretty well after many Youtube videos and online research. I found full blown spider webs and dead spiders! I have encountered a few of issues as I'm putting it back together and I wonder if anyone might be able to help. 1. I took off the screws of the back of my OTA (I know I shouldn't have!) and now I'm not sure how to put them back on (see attachments). When I try it seems to push the primary mirror instead of fastening to anything. 2. My secondary mirror flip is broken, the plastic piece part fell off. Is it possible to fix? The mirror itself is also very dirty (see attachments) and I don't think it can be cleaned further. Any tips on how to replace it and where to buy the parts? Or is it possible to not use the 90 eye piece viewport and instead use the front one so I don't need to fix the flip or the mirror? 4. My secondary baffle is sliding off. I've read that this is a problem w/older models. I tried pushing it to the right place and it requires some force, but after 1 minute it slides back to its original place. What should I do? Does this matter? 5. The plastic attachment to hold the smaller lens (finderscope?) wobbles no matter how tightly I screw it on. I don't know if it has anything to do with the front plastic part being a little broken. Thank you for your help in advance, and I am still learning terminology so be easy on me

Here is the telescope project I am currently working on. The big picture is to have a 900mm Newtonian on a Bailey split ring equatorial mount. The rig will be used in a backyard mini remote observatory and also be portable. I may put it on a small trailer I have, I'll have see how "portable" it is first. I might be able to just put it in the back of my SUV if it's not too heavy, then just mount light duty wheels on it for carting it around the yard. Most of the time it will reside in the backyard, under cover of a mini remote observatory, well that would be nice anyways. At the very least it will have a small enclosure to protected from the elements and to keep it ready for imaging. I won't go into details on how I am going to control everything, because I don't know yet. I do have a generally layout for the scope cobbled together. It is a Serrurier truss ~900mm f/6 150mm. I'm going to try to keep the trusses symmetrical front to back, but the COG may change depending on how things weigh up. When my mirror blank gets here I will be able to start building my mirror cell. I've already got that part more or less figured out. I'll fine tune the drawing based off of actual measurements, right now I've just drawn a 6" nominal blank. It is a moving mirror frame with roller edge support like what Lockwood and JPastro use on their big mirrors. I've just made mine under-hung to line the COG of the mirror over the collimation points. I am going to grind the primary and fashion a secondary elliptical mirror from Zerodur flats. It has a 1.2" /1.92° diagonal 100% illuminated area which will cover a cropped DSLR sensor using a 2" secondary. The central obstruction is 33%. I'm flip-fopping on the focuser right now. Ideally it's going to be stepper driven kind of flat Crayford dovetail sled thing. The nice thing about this concept is I don't need a T-ring or anything, perhaps just a field stop baffle, the camera would be mounted by the 1/4"-20 connection on the camera. This plan might be temporarily diverted in favour of a simple manual helix focuser. My DSLR is a Sony, so I can't go crazy just yet until I know how to get the Sony working with autofocus, remote imaging etc, if it's even possible. It's looking like I'll have to get a new camera down the road at some point and build the custom sled then. This means I will probably make the front half of the OTA removable to accommodate an upgrade, which is less then ideal but perhaps the pragmatic thing to do. The helix and T-ring would make attaching a collimation cap possible, I wasn't sure how I was going to collimate the DSLR on a sled using live view, though I'm think something could be sorted out when I go that route. The focal ratio was chosen as a balance of field of view, tracking abilities, ease of mirror fabrication and dependencies on correcting optics. I was originally considering f/4 or f/5, but this requires a higher degree of skill and effort to make the mirror and makes the mirror tied to a comma corrector. I would prefer to have all reflecting optics only. I don't want my fancy pants mirror to be dependant on a refracting lens, that would be blasphemy. lol. I'll save the coma corrector purchase for a big fast visual scope one day, my mirror is small and not visual so why battle coma. Also with f/6 I'm hoping is going to have a decent field curvature plane vs a faster mirror for my DSLR sensor. It will be made from 17.5mm/~3/4" Baltic Birch plywood. The OTA below is ~900mm/36" long and 305mm/12" in diameter. Baffling will be added and fine tuned later on. I'm really only concerned with 100% FIF but in reality it's very close to the 75% illuminated diameter in this configuration, so will just go the the 75% baffle diameters that Newt for the web gives me. It is a fun project.

Hello Everyone! This is my first post to SGL, but it's certainly not my first visit. I've been a reguar leech to the wealth of information on here and have amassed a plethora of equipment for exploring the night sky that evolved from an 8" 200P Dobsonian, and finally up to its current "Mark IV" as the 8" Newtonian Equitorial you can see in the photo. I'm aware of the ettuiqette here, and this isn't a "hello" post, no. This is me sharing my write-up for the 12v Power Supply that I made myself in the eventual journey to my fully remote observatory (hopefully opening 2018) at the end of my garden. Hoping to maybe give something back to the community that i've taken so much knowledge and tips/tricks from over the last 18months; because 19months ago, I'd never even put my eye to a telescope eyepiece and now I'm flocked, guided, and powered. So thank you everyone for that. I've written half of the write up for it last night, pt 2 to follow soon I hope it's ok to share an external link to my personal Blog: http://milkandbourbons.tech/telescope-power Finally, its not in the Blog just yet, but here's the picture of the final, finished powersupply. It's a little rough looking 'cos I didn't order as much wire as I should have, but it does the job amazingly! Thanks for reading! Deano

Now when I have APT that control the camera it could be a bit boring when waiting. Maybe I could do some visual observations when the camera are doing automatic photographing? I'm not a big fan of visual observation, but I recently bought a big 25x100mm binoculars and think it could be fun to have. It's very heavy and could not be handheld, I have to built a mount for it. This is something new to me so I reading forums and get ideas and figure out my own solution to it. As a first part I bought a caster wheel to have as a roller bearing. I will mount that on my second pier. If you find it interesting you can see more details here and follow my project: http://astrofriend.eu/astronomy/projects/project-big-binocular/project-big-binocular.html /Lars

Hi there, can anyone recommend the optimum length for a pair of dew shields for my 15x85 binoculars. Kind Rebards Paul J.

Hello reader, Appreciate your time to read that topic. Have you ever tried 3D printing tech to create/design any of your astro components that may substitute expensive ones?. I'm curious to know your thoughts about it. Thankfully, Bamo

[A few more photos are in the imgur album] Made this telescope for observing sunspots. The Sun gets projected onto a piece of paper after bouncing from 3 mirrors inside the frame. It's compact, light, takes only a few seconds to point at the Sun, and sketching sunspots is as easy as circling the spots on a piece of paper. It can even project the Moon: The design is inspired by a commerically available telescope, but I’ve done all the designing myself, just for the fun of it. Sunspotter is full of little details that make it interesting. How do you fix the eyepiece in the exact place where it needs to be? How do you keep the lens in place and perfectly aligned? Building the telescope was a lot of fun, I’ve learned to use a jigsaw, X-Carve and a 3D printer. The plan is to use it to complete the Astroleague Sunspotter Observing Program, but unfortunately I completed it at the minimum of a Sun cycle, and won’t see any sunspots until next year. Telescope parameters: Magnification: 75x Size: 41cm x 41cm x 15cm Weight: 1kg Design: Keplerian Projection size: 75mm Materials needed: Lens: Ø52mm f=750mm achromatic doublet Mirrors: 1, 2, 3 Eyepiece: Baader 10mm ortho 1.5m² of 10mm plywood Wooden glue 5m of PLA filament 12 nails Compressed air Isopropyl alcohol Tools I used: Jigsaw with a 30° bevel capacity X-Carve 1000 3D printer A laser pointer Clamp Learned modelling basics in: LibreCAD Easel TinkerCAD Fusion 360 Part 1: Choosing the lens The idea of a sunspotter is that the light goes through the lens, travels inside the telescope, bouncing from 3 mirrors, enters an eyepiece and the image gets projected on one of its sides. The distance the light travels before entering an eyepiece is the focal length and it determines the size of the telescope. I chose a Ø52mm f=750mm achromatic double. Observing the Sun doesn’t require a large aperture, 50mm is more than enough. I wanted a high magnification and went for the longest focal length I could find, which was 750mm. Achromatic doublet design is what people use in refractors. If it is good enough for a refractor, it’s definitely good enough for my project. With the focal length chosen I could design the wooden parts. A drawing showed that the frame needed to have sides 30cm long, but I wasn’t sure about the placement of the mirrors and went for 31cm sides, planning to shorten the light path as needed by adjusting mirror positions. This is the LibreCAD drawing of the layout of parts on a piece of plywood: Part 2: Building the base Having a drawing of the base in LibreCAD, I printed the drawing 1:1 scale on multiple A4 sheets of paper and glued them together. I transferred the drawing to a piece of cardboard and cut it out. Applied this cardboard template to the sheet of plywood, and cut out two parts with a jigsaw.. I’m not an experienced user of jigsaw, and couldn’t manage to cut half-circles accurately enough. Even worse was that the two parts were very different. I didn’t want the frame to randomly tilt left or right when adjusting its altitude, and had to spend a lot of time with sandpaper to make the halves as similar as I could. Glued the two large parts with three small parts in the middle. Additionally nailed the parts and the base was ready. Part 3: Frame The frame is simply a triangle made of three pieces, with short sides cut at a 30° angle. Most jigsaws can cut at 45°, but not at 30°. Had to buy a new jigsaw with a 30° bevel capacity. Cut out three sides, cut short sides at a 30° angle, but didn’t put them together just yet. The lens needs to be perfectly aligned with the Sun-facing part of the frame, otherwise the Sun projection isn't circular but elongated. My solution was to carve a hole with a little step as shown on the image. The inner hole is Ø46.5mm, the outer hole is Ø50.8mm. The outer hole is the exact size to let the lens fit, but with a little bit of friction. Had to carve several holes to find the minimal size the lens could fit in. The step is just large enough to have enough surface for the glue to keep the lens in place, I didn't want to reduce the aperture too much. I used an X-Carve for carving and Easel for modelling. With all 3 sides ready, I could assemble the frame. It appeared that my 30° angle cuts were not very precise, but after some sandpapering the sides started fitting together alright. Glued the parts together and left them to dry for a day. To apply some pressure on the joints, I wound several twine loops around the frame really tight, made sure all sides fitted well together and left it to dry like that for a day. Part 4: Mirrors When selecting mirrors I was looking for the smallest mirror that fit the cone of light. Small mirrors are a lot easier to place, and they let me better control the length of the light path. I considered using elliptic mirrors, but they were bulky and really hard to place. All mirrors are first surface mirrors, otherwise planning their locations would be a lot more confusing. This was my original plan of placing the mirrors: As you can see, all the angles and distances were carefully measured, and I wanted to simply make mirror holders of those exact dimensions. This was clearly a bad idea. I 3d-printed some parts like this: And only later I realized that the frame angles are not exactly 60°, and that there are drops of glue along the edges that don’t let me fit the pieces deep enough in the joint between the sides. I cut angles from all the mirror holders: After I put the first mirror in place I realized the angles are all wrong, and that I needed to re-do the holder. Separating the mirror from the holder was a huge pain, which resulted in an accident. The mirror fell off the desk and got damaged. Luckily, only the back side got damaged, the front side was still working: The final designs of mirror holders looks like this: The holes in the front surface let me apply pressure on the back of the mirror if I ever want to separate it from the holder. The recesses collect the excess glue to avoid mirror skewing when gluing them. All other holes are simply to save the filament. Part 5: Placing mirrors What I learned is that you can’t plan positions of several pieces with high precision and just hope that it all comes together. I needed a feedback about the precision of mirror positions. I used a laser pointer to verify mirror positions at each step. In the picture you can see that the laser is firmly set in a hole in another piece of wood, with layers of isolation tape on the tip of the laser pointer to make it stable. A clamp holds the piece of wood in place, ensuring that the laser ray goes in the same direction as a solar ray would. A crosshair of black thread at the center of the lens ensures the laser goes exactly through the center of the lens. When placing each mirror, I marked the spot where I expected the laser to end up. While gluing the mirror holder to the frame, I kept the laser as close to that spot as possible. If for some reason, the laser couldn’t hit the expected spot, I did my best with placing the mirror, and recalculated locations of the following mirrors. I saw the first sunspots after placing all the mirrors and simply holding an eyepiece in hand. Part 6: Eyepiece holder I tried eyepieces of different focal length and liked the picture I got with a 10mm eyepiece the most. An eyepiece needs to be in a very exact spot to produce a sharp image. At this point it was obvious that my frame doesn’t match the model, and that I didn’t even know what exactly was wrong with the frame. I didn’t want to rely on the model and moved forward with trial-and-error. I printed several parts to hold the eyepiece, with different eyepiece locations: The part in the photo was a total disaster. It needed quite a lot of filament, at the same didn’t have enough surface area to be glued to the frame, and not enough surface area to hold the eyepiece firmly. The next iteration was a lot better: This part has a lot more surface area, and needs less filament to be printed. I intentionally printed the hole for the eyepiece too small, and had to sandpaper it a little bit, to make the eyepiece stay firmly fixed. Adjusting the focus is done by sliding the eyepiece up and down until the Sun becomes a circle with well defined borders. Part 7: Dust All optical parts should be kept clean. Dust on the mirrors and the lens will make the image darker. Dust on the eyepiece will show up as artifacts on the projected image. Unlike sunspots, the artifacts will not move with the Sun. To clean the eyepiece I used compressed air. To clean the mirrors I used isopropyl alcohol. Part 8: Fire safety Don’t leave devices with magnifying lenses lying around. Once the Sun happened to be in such a spot that its light went right through the lens, burning through the cap of the eyepiece. Luckily, nobody was hurt and no other damage was done. Part 9: Future work Build quality of the base is very poor. The frame tilts sideways when adjusting its altitude despite all my efforts. I’d like to build a new base, but leave all the work to the machines. I already have a model for an X-Carve to make both base parts, compatible with my current frame: A notch along the edge of the half-circle should eliminate the tilt. The precision of the machining should make the base very stable. Maybe next year, when sunspots become a common daily sight, I’ll get to this project. Thank you for reading this far! I hope you enjoyed it.

Have you ever thought about why your Newton telescope has the dimension it has, primary and secondary mirror, focuser, f/number and so on? I stumbled in to this tool Newt-Web that Kenneth H. Slater has developed further from Dale Keller's code. It's an online design tool page for Newton telescope. It's a very intuitive page where you can put in some figures about a Newton telescope that you want to built and get back information about it's performance. It give a ray trace and important data back. From that you get understanding when a Newton telescope design is good or not. I have done some test and written it down on my homepage so you can see the different steps and my comments: http://astrofriend.eu/astronomy/projects/project-design-newton-telescope/project-design-newton-telescope.html I already know some of the physics and math, but never got to know so much in short time what happens when you change a parameter and what happens inside the telescope. Beware, I'm still in the learning process and not all what I have written is fully correct. I recommend you to take a look at Newt-Web page even if you never will built a telescope, you get knowledge and understanding that could be very valuable when you shall buy a Newton telescope. /Lars

Hi there, I've been searching for a supplier or manufacturer of wooden observing chairs in the UK, with very little success (plenty over the pond). Do any SGLrs know of a source for these in the UK? I've looked at the Geoptik offeirng 'Nadira', but not sure of the build quality. In addition the base looks too narrow to me, also, being a short a##rse, the lack of foot rests in the design is a negative for me :-) Looking for something akin to this: Kind Regards Paul J.