vlaiv

PC requires quite high print temperature - often above 280C. Do you have all metal hot end on that Anycubic Mega S?

Anyone tried ASA as ABS replacement? It is supposedly better and does not give of nasty fumes when printed

I did not have heaps of experience with collimation when I gave it a go on my RC - and it was just usual stuff - find good tutorial and follow the steps. Things behave the same - tighten / loose screws and observe what happens. Only difference was that I used camera instead of eyes to judge changes. I did change mine - but that is just because I really prefer threaded connection. At first - I used stock focuser and it was ok, but in the end decided to get an upgrade. Try it first - it is not poor - maybe you'll find it to be sufficient for your needs. No you don't. I use my RC8 without flattener / reducer and it works fine up to 4/3 sensor. Maybe even APS-C would work, but I have suspicion that I would look into field flattening for such sensor size in 8" version. With 6" version, since it is F/9 - maybe things are the same and maybe APS-C will make flattener more mandatory. There are three options that people use: 1. Flattner without reduction 2. Reducer without flattening (or small amount of) - usually used is CCD47 / CCDT67 (first is Chinese knockoff and second is original - AP reducer for F/8 and slower systems with flat field). 3. Combination. Here I've heard that Riccardi x0.75 FF/FR works good and I think people tried other but I have no idea if there is preferred one. I will at some point try TSRED2 x0.79 to see how it works. Just bare in mind that if you are using 2) - CCDT67 - although it works as x0.67 - depending on the sensor size - you won't be able to utilize full reduction. Field is corrected to about APS-C size so 28mm, maybe 30mm (this is 8" version - 6" maybe even less although given it is F/9 - it might be the same) - so if you reduce it - you might end up with corrected field smaller then sensor size. 4/3 sensor for example needs x0.72-0.75 reduction and more than that starts showing corner star aberrations. In any case - nothing preventing you to just go without anything - I use mine like that most of the time. I did not have issues with that, but yes - tilt adapter can be useful, much like with any imaging setup if you happen to have tilt. Here it's not guaranteed that you'll have it - so do collimation first if needed and only think about it if you end up seeing tilt in your images.

Also good guide for mechanical properties: https://www.simplify3d.com/support/materials-guide/properties-table/

I'm a bit confused with terminology. What does the strength mean as mechanical property? https://www.youtube.com/watch?v=ycGDR752fT0 PLA is strongest, stiffest but also the most brittle compared to ASA and PETG

Yes - polar alignment will produce DEC drift and mount tracking issues will produce drift in RA. You have RA drift - so it is periodic error. To confirm - do shorter exposures and trailing should be shorter and shorter. At some point - most of your subs will have round stars. Best way to eliminate this issue is to guide.

As long as there are no requirements for high temperature resistance - it seems that PLA is really the best and easiest to work with.

I just figured out the way to "3d" print - circuit boards Well, not really, but it did occur to me to use filament to create etching mask on PCB - and quick search online showed that it is really not feasible as filament won't stick well enough to PCB and etching usually fails. However - if we combine two things - we can still get decent 3d printed circuit boards. Most basic masking method - using black permanent marker to trace out leads on PCB prior to etching - like in this video: https://www.youtube.com/watch?v=VenCNTvXqFc and then we add a bit of this: https://www.youtube.com/watch?v=OmgT__nU9po It's just 3d printed magic marker holder that attaches next to hot end . In "drawing" mode - we don't heat the bed nor heat up the hot end - magic marker will be lower than hot end which we deal with z-offset. Then it is just matter of "3d printing" our PCB traces on board

I do post a lot of stuff, so not really sure which one are you referring to. In any case - I think original question has been answered quite well. Focusing can be defined as aligning of two focal planes - one of the eyepiece and one of the telescope (however, keep in mind that there is no singular focal plane of the telescope - focal plane depends on how close or far away observed object is. Close objects shift focal plane further away. If we place object at focal length away from objective lens / mirror - we move focal plane to infinity! With scope with moving optical elements like Maks and SCTs - position of focal plane also depends on separation between optical elements. Similarly - there is no single focal plane of the eyepiece. In ideal case - object at infinity and observer with good eyesight (no need for glasses) - both focal planes will be situated at exact focal lengths of respective optics (OTA and eyepiece).

That is soooo cool! I have whole another "section" of things to add to my 3d print list. When I was very young I had a friend that enjoyed a common hobby with me at the time - aircraft (and other military) model making. Nothing serious, just those injection molded kit models that you assemble and paint. I recently made contact with that friend again and in conversation - we did touch upon doing that - and then it occurred to me - here is nice thing to do with 3d print - both model in 3d and print / assemble such models like tanks, planes, cars and so on ... Then, another day I had this very interesting idea. It is a bit crazy, but I think it is rather innovative and cool - it would probably be one time massive project, but I guess someone interested in that sort of thing would have really good time. It is again use of 3d printing - to make stop motion animated video. Instead of modelling actors from clay or silly putty or whatever - one could use serious animation software to 3d print models in motion. It does not need to be single model per frame - models with moving parts can also be used to do stop motion and of course - re use of models in different poses. Now, seeing this video - another cool "sub hobby" occurred to me. I used to love "TIM" - computer game titled The Incredible Machine. I think that 3D printer allows TIM to be played in the real world as your video shows.

I wanted those for a long time Maybe I'll go baby steps and get 3080 for PCB milling and drilling first. Would like to be able to do nice looking DIY boards without too much mess.

I often keep a mental list of all the things I want to print as soon as I get one - Dew shield + aperture mask (avoids star spikes) for my Samyang T1.5 85mm lens - Motor focuser bits for Samyang lens (case for arduino and bracket for the stepper to be mounted on the rail) - Some distancers / inserts for counter weights system I made for AZGti in EQ mode (couter weights were exceptionally cheap 0.5KG dumbbell weights from Decathlon - but they have 30mm central bore) - Levers to put on M10 bolts holding above CWs in place - Bits needed for auto focusers for my two other scopes: two mounting brackets and single arduino box to be shared between the two as they will have same steppers driving them. - cases for DIY spectroscopes - I would like to 3d print a telescope - or at least bits for diy telescope, for example, salvage lens from old binoculars and then make wide field refractors or finders out of that - aluminum tube but all other bits will be 3d printed. - Dew shield for Mak102 with mounting system - like screw on light weight dew shield - fully functional star tracker - that is my most ambitious project. It will use cycloidal reduction gearbox, steppers and all the bits needed to mount and point the camera. Most of it will be 3d printed with exception of screws holding it together and bearings for smooth tracking and steppers of course. I'm sure there are others as well that I can't remember at the moment.

I don't follow. How it is supposed to work? Really accurate polar alignment is supposed to keep DEC from "discretely eventually creep" away from fixed position

In this case - I do think you should seriously consider 6" CC. It is a bit over the budget but it will be more compact and easier to carry (although it is a bit heavier). It will also give you better views than say F/5 newtonian. F/6 and slower newtonians will probably be on par or even better, but fast F/5 newtonian is not the best choice for planetary views. Collimation needs to be spot on and faster scopes usually have larger central obstructions. For comparison, TS scopes from FLO: F/5 newtonian has 63mm central obstruction, weighs in at 5.9Kg and is 690mm long F/6 newtonian has 45mm central obstruction, weighs again 5.9Kg and is 845mm long 6" CC has 58mm central obstruction, weighs 5.8Kg and is 440mm long In order to reach say x180-x200 magnification with F/5 and F/6 newtonians you'll need short FL eyepieces - or use of barlow lens. Good short FL eyepieces and barlow add cost. With 1800mm of FL - you can just use 10mm plossl or ortho (those still have some eye relief) and you are at x180 with excellent sharpness. This part I again don't get - why do you need EQ mount counterweights? Not sure where you got that load for AZ mount - quick search gave me this: "The Skywatcher AZ-3 is a practical altazimuth mount, easy-to-use and providing good stability. It can serve as a base for terrestrial or astronomical observing and support telescopes or spotting scopes up to a maximum weight of 5kg (refractors of up to 120mm aperture and reflectors of up to 150mm diameter)." and this: I had AZ3 mount and I did not particularly like it, but if you are fine with it - then I think it will work for you (better with shorter scope than with longer one). Again, I don't want to pile up expenses, but if you want stable light weight mount, maybe check out this: https://www.firstlightoptics.com/portable-astronomy-mounts/scopetech-mount-zero.html Coupled with decent sturdy photo tripod (I know, more expenses) - it will be lighter and better option than az3.

I don't have SA, but what about motor controls? If it can be guided - it can be instructed to move in RA direction as well - you can probably use that instead of clutch to move mount to wanted position. Regular mounts have x2, x4 and so on sidereal move rate - not sure if SA has something like that - but you can use that to move it forward, backward in RA? This is from manual:

Hi and welcome to SGL I'm a bit confused by your post - or rather some parts of it. First - there is going to be quite noticeable difference between 90mm and 150mm - even if one is refractor and other is reflector. This holds true for both planetary views and DSOs. Here is my first question to you - you say that you walk quite a distance, yet you mention that you mostly are interested in the Moon and planets. You don't need dark skies to observe those. In fact - sometimes it is even better to have some light sources around you so you don't get dark adapted when observing moon and planets - as dark adaptation lets you see fainter stuff but reduces sharpness of your vision and color sensitivity - that helps to see detail in planets and the moon. What is your budget? From what I've gathered, maybe best scope type for you would be 6" SCT? It is still rather light weight - below 4Kg, and will sit nicely on that Alt az mount. Here is second thing that I don't fully understand - you mention that you prefer low power views. There are couple of main drawbacks of SCT design (in my view) that limits its usefulness as all around scope - first is price. It is much more expensive than newtonian of same aperture (for some unknown reason), it has corrector plate that is often dew magnet (can be sorted with dew shield and dew heaters) and is F/10 system - which means that it is rather limited at wide field views. When you say low power views - do you mean that you like to observe the moon at x100 instead of say x180, or you mean that you enjoy powers around x30-40? With SCT 6" - you'll be limited to powers above x50-60 unless you go for very narrow field of view or accept serious vignetting (with 56mm plossl you would get 1500/56 = ~x27 but I seriously doubt that C6" will illuminate full 47mm field stop). In any case - I'm not really sure that AZ3 will handle F/5-F/6 6" Newtonian. It is worth upgrade and certainly exceptional value for the money. If you want more compact scope (and money is not issue) - look at C6. Maksutov scopes will give you even higher magnification but are good planetary scopes. If you want 6" one - maybe check out 6" CC like this: https://www.firstlightoptics.com/stellalyra-telescopes/stellalyra-6-f12-m-crf-classical-cassegrain-telescope-ota.html It is a bit heavier at 6Kg, but does not have front corrector plate. It will properly illuminate something like 56mm 2" Plossl which will give you rather decent low power view at x32, and it will be excellent planetary scope. Since you have 900mm refractor already - x32 is like using 28mm plossl on that scope (a bit less magnification than supplied 25mm EP but a bit more than say 32mm plossl). Hope this helps.

Never thought of it Here are some possible ways to remember things by - Ra is Egyptian sun god - and sun moves across the sky as does mount track in RA? RA is right ascension - mount can rotate left/right in axis that tracks earth rotation? Deck - or platform is something stable that does not move - DEC axis does not move when mount is tracking normally?

yes This is needed because of the way Ha filter in quark (and other solar filters) work. It is interference type filter often called Fabry-Perot etalon (although quark uses some sort of mica crystal that operates pretty much the same). In any case - that is best described / explained as two parallel plates that must be at exact distance (filter tuning is getting these plates at exact distance). It is needed to be so with respect to wavelength of light - it must "bounce" back and forth (quantum phenomena) at exact rate to cancel all other frequencies out. This requires light to hit that filter at right angle to it. If angle is slightly different - then path of light thru the filter gets longer: Distance at an angle is longer than direct distance - red arrow is longer than black. If light is coming at an angle - it throws the filter off band (or rather presents itself to filter as different wavelength). This happens also with regular filters - that is why you have special filters optimized for fast optics. You can't use regular Ha (for night time imaging) filter on say F/2 or F/3 system - it won't work as good. Regular Ha filter for night time imaging has something like 3-7nm pass band. Solar filter has 0.5-0.7 angstrom pass band or 0.05-0.07nm - that is x100 narrower pass band. For this reason solar ha filter needs much more parallel rays as it is much easier to throw it off band if light is at an angle. High F/ratio creates almost parallel rays. In ideal setup - light going thru solar Ha filter would be perfectly collimated. This is how front aperture Ha filters work (light coming from far away is effectively parallel rays) or sub aperture filter in telescope - like with Lunt 50 scope: (screen shot describing how etalon works - there are two lenses - one that makes beams parallel, other that refocuses light). In reality - rays are not at 90 degrees with this setup either - only principal ray is - because sun is not point source - it has some width - so if you point the scope at the center light from edge will come at 0.25 degree angle to optical axis - but those angles are small.

There are some differences with camera binning that are be beneficial for planetary type imaging - like faster download rates and hence high FPS. I don't have hands on experience with Ha solar so I have no idea of how fast the features are changing and what is imaging time limit, but from what I've gathered sun is rather dynamic in Ha so there is time limit on individual recordings and higher FPS is definitively going to help (for lunar for example - one can use slow fps and get enough frames over say half an hour, but for solar I think feature motion blur would occur on these time scales). Play around with binning settings on your Apollo to test things. ASI2600MC can be used but you have to be careful of how you use it. It is color sensor and only red pixels will record Ha light properly. This means that every other pixel in X and Y will be effective. Problem is - you'll still need to download full image, so you'll be wasting 3/4 of your USB bandwidth / data transfer speed on data you'll throw away. Then there is problem of pixel size matching. Single pixel is 3.76um but again - you are not using every pixel but every other pixel, so your actual pixel size is 7.52um. That is neither here nor there with respect to optimum sampling. We have seen that optimum pixel size is around 9um. 7.52um is smaller and you'll be over sampling with that - and that is bad because of SNR. I have no idea how strong Ha signal is with quark combo in a planetary type exposure and will SNR of single sub be issue (for planetary it is, but for lunar it most of the time isn't as moon is very bright - unfiltered at least). Binning that in software later will fix SNR thing - but again, it will be under sampling at 15um. In any case - ASI2600MC is not the best camera for this - no color camera is. Mono is the best solution for Solar Ha. That does not mean that you can't try with this camera - just keep in mind limitations of it.

Quite the opposite. With regular quark - you get two constraints that you don't have with quark combo: 1. smaller blocking filter 2. integrated x4.2 telecentric lens that you can't change. Quark combo does not have those restrictions so it's better option in general as far as imaging is concerned. Now onto the rest, so let's do it one by one: Quark needs to operate at certain F/ratio. It really does not care how that F/ratio is achieved (to a point - it prefers telecentric over barlow as discussed). F/ratio is ratio of aperture and focal length - you change it by altering one of the two. You alter focal length by use of telecentric extender. You alter aperture by use of aperture mask. Any combination of the two that produces required F/ratio is good. For given F/ratio there is optimum pixel size - around 8.2um in the case of F/25 and 9.84um in case of F/30. If you want exact formula - it goes like this pixel_size = F/ratio * 0.656 / 2 (that is just inverse of f/ratio = pixel_size * 2 / wavelength - which is formula for critical sampling with wavelength set to 656nm or Ha wavelength). This shows that regardless of the setup you are using - detail on the sun will be limited by size of sensor. Your sensor has 6.6mm of height. There is only so much pixels you can squeeze into 6.6mm if each pixel is ~9um. You need to leave some room for proms - but that is it. Want to fit whole solar disk onto sensor with higher number of pixels - get larger sensor. This holds for any aperture size and tele extender combination used - because all result in same F/ratio and same ideal pixel size and if you have one ideal pixel size - well, there is so many pixels of that size (either native size or binned) you can put on sensor. Back to last post - I just showed you that you can have both full disk image and zoomed in image with combination of equipment that you already have if you get quark combo. Only limit is that it will have certain resolution. This is not the limit of neither quark nor scope nor telecentric lens nor aperture mask - it is limit of sensor and ideal pixel size. Want to do the same but have more resolution? Get larger sensor. I think it is sensible route to start of with sensor you already have, get some good images - both close ups and full disk (neither is easy and both require practice in capture and processing) and when you feel confident and ready (and funds allow) - look into getting bigger sensor.

It won't change the size of image. It will make rays of light more parallel - that is requirement by solar filter. We add telecentric lens in the first place in order to satisfy F/25-F/30 requirement by solar filter (it says that quark combo can work from F/15 - but I would advise to experiment and see how much contrast one looses with F/15 in comparison to F/25-F/30, after all - regular quark has x4.2 and works best with F/6-F/7 scopes - precisely F/25-F/30). That as a consequence makes solar image larger in the focal plane (increases focal length of the system and gives "more magnification"). If we don't use telecentric lens - that keeps image small as originally is - but creates problem of having system at native F/7 - which will cause issues for filter. We use aperture mask to increase F/ratio and make light beams work properly with filter. Make sense?

How do you control temperature?

Barlow and telecentric lens do almost the same thing - they amplify the image at focal plane (in effect extend the focal length of telescope) and they both increase F/ratio of system. There is subtle difference in how they achieve this. We say that that solar filter best operates at F/25-F/30, but what we really mean is - solar filter best operates if light rays are almost parallel to each other and perpendicular to filter. Look at this diagram: Barlow diverges rays of light. More away from center they are - more angled they end up being. Telecentric lens "separates" them more - but keeps them more "parallel" in the end. Both will operate the same in the center of the field - but as you start moving away from center - barlow will start causing issues for filter - it will stop performing to the specs and contrast will be impacted - like when using filter in say F/10 beam instead of F/25-F/30. You can try with barlow to see what sort of result you get, but ultimately, you want telecentric to get the best results. Good thing about quark combo is that you can choose how you achieve F/ratio of your system. You can increase it in two ways: - use of tele extender - use of aperture mask. Difference between the two is that first one increases focal length of the system, while second one does not. Larger focal length requires larger sensor for same FOV (same as solar disk in this case - or just a bit larger than half a degree). You can image full solar disk with your camera if you don't use tele extender, but instead use aperture mask. In order to achieve say F/25 with 714mm of focal length - will need 714/25 = 28.56mm aperture mask - let's say 28mm one. What is the drawback of this method? Well, you won't get very detailed full disk image. Your camera is 4.5um pixel size and resolution 1944*1472, but we have seen that you need pixel size of around 9um so you'll bin your camera 2x2 to avoid oversampling and get sharp image. This means that your solar image will have only about 700px across. You can't expect sharper more detailed image with 28mm of aperture. In order to get more detailed solar image - you'll need larger sensor. If you are happy with this - then there is your solution - you can have several different zoom modes for your scope: - no telecentric lens + 28mm aperture mask for full disk solar imaging - x2 telecentric lens + ~50mm aperture mask for medium zoom imaging - x3 telecentic lens and ~80mm aperture mask for close up imaging

No it won't be possible. Problem is with integrated x4.2 telecentric amplifier and blocking filter diameter. All of this happens before there is chance for reduction - so you'll be reducing already clipped image. Sun is about half a degree in diameter - with 714 x 4.2 = 3000mm of focal length. That makes radius (quarter of a degree) of sun image (little trigonometry) about 13mm or diameter about 26mm Regular quark has 12 mm blocking filter. That is about half of what we calculated. For this reason you need less than 450mm for full solar disk observing - and even less for full solar disk imaging (observing tolerates small vignetting as eye can't distinguish it easily). If you want to image rather than observe - then look at quark combo. That one does not have integrated telecentric lens - you need to add your own to get to F/25 - F/30 (either add telecentric lens or use aperture mask or combination). It has 25mm blocking filter with 21mm clear aperture - so almost double of regular quark. Only issue is that you need your telecentric lens - something like this: https://www.firstlightoptics.com/barlows/explore-scientific-2x-3x-5x-barlow-focal-extender-125.html For example - x2 model will give you F/14 scope with 1400mm of focal length. That will be suitable for full disk imaging and you can get to say F/28 by using 50mm aperture mask. With 1400mm of focal length, solar disk will be about 12mm in diameter - so you need sensor that has height of 13mm or more. ASI1600 is good example. Or in this case - you can use 0.5 reducer to shrink Sun image. But be careful - you'll loose some of sharpness with reducer. Another thing to consider - at F/28, ideal pixel size for Ha wavelength is 9.2um. This means that you'll need to bin your pixels, so it is best to fiddle around with parameters (aperture mask size, telecentric amplification factor, pixel size and binning and sensor size) in order to get best match for full solar disk.