Thalestris24

See here: DeepSkyStacker FAQ (free.fr) Louise

It's very satisfying when a thread works. It's very unsatisfying when a thread doesn't work! Louise

Hi again I meant to ask what the cylindrical protrusions are for - just to provide some grip, maybe? I printed out a 58mm x 0.75 thread part this evening It actually worked first time - miracles do happen! It's for part of a (focus rail) microscope illumination system (a work in progress ). Microscopes can be as good a source of diy/3d projects as can astro gear! That reminds me - I must get back to the Lowspec spectrometer that I started over a year ago! I put it to one side - never a good idea, really. It's all built but needs some tweaks and commissioning, and maybe some reprinting of parts. Louise

Most of the problems I had were to do with the bed not being level, or not staying level. I realised after a while that the y-axis was loose... Tightened that up and improved things but still had problems. Upgraded the bed springs - big improvement, but still had some stability problems. My next hopeful is to add nuts to the loose bed screws. I'll be doing that soon. I'm only using the printer occasionally. Yes, there are filament issues but they aren't the main problem. I have a new reel of pva to put on. However, it will last me about a year. I suppose I really should take the reel off and put it in a sealed bag with some silica gel after using the printer. I think I did start a 3d printer topic about 18 months? or so ago but it was just a topic in the diy astronomer thread. I'm sure there have been others. Louise

You have a posh printer!

Hi A lot of problems I've had the printer was definitely the problem. But yes, pla filament properties change over time mainly because of its hygroscopic nature. I first got the printer about 15 months ago and more or less went straight into using it to build a spectrometer. However, I really should have got more familiar with the printer first live and learn! Since then I've only used the printer sporadically and for making small parts. Any parts involving 0.75mm pitch threads are still a challenge! Louise

i came across this thread calculator which might be generally useful: GewindetoleranzRechner ISO-Gewinde DIN 13 (iso-gewinde.at) here is M72 x 0.75 I plugged in: ThreadCalculater.pdf It gives a male thread core diameter of 71.058mm - pretty much what I thought! Louise

Yeah, I was looking at M72 x 1.0mm on the grounds that the tolerances should be close (enough?). Looks like the base size should be 71mm or maybe a leetle bigger. Hope it prints out ok! Louise ps camera filters mostly have a 0.75mm pitch so there should be a spec somewhere...

Hiya I take it you selected 'modeled' for the external thread? You could use the inspect -> measure in fusion to check the thread measurements. Also maybe try tweaking the values including reducing the base diameter (shouldn't actually be 72, I don't think..). Does what you've printed measure correct? We need a mechanical engineer's help here... Louise

I was just thinking I wasn't sure why the labels 'external' and 'internal' are used - 'male' and 'female' would do me! Also re: tolerances doesn't necessarily take into account your 3d printer precision/variability/stability. I generally have to have several goes on my Ender 3D Pro to get a thread that fits properly, especially with 0.75 pitch (though 1mm pitch is usually ok). So that usually involves adjusting the tolerance values - trial and error! I'm currently trying to upgrade my printer somewhat and firm up the bed. I fitted upgrade springs which helped a lot. Hopefully, once I've made the further improvements it will be a more precise and reproducible printer. If you're fortunate enough to have a better printer, it may not be such a concern. I've looked at different models e.g. the Ender 5 Pro and the CR10S, but I'm not convinced either of them would definitely be better than I already have. Louise

You should probably change the ThreadDesignation label also Louise

Hi Here is an example of adding an M49 thread which worked ok Maybe you can just compare? Louise M49x75_Thread.xml

Hiya I think you just need to add your values and label to Paul's xml file above Louise

I can't say - you'd have to speak to someone who has, or has used, one.

Um, I don't have one! That's an old post... I was considering getting one a while back but didn't in the end. Louise

I think it must have been - it was some years ago (2015, I think). Reflectors can be a pain to maintain as well as being bulky. Louise

It's not in a fit state to be passed on to someone else. I had a lot of trouble with the focuser not being square to the tube and not being able to collimate properly. In the end I gave up on it (life is too short!) and moved over to the much simpler and hassle-free refractors/lenses. Louise

But you don't need to spend so much if only imaging with a camera/lens or 80mm frac and definitely not so much if imaging through a bedroom window!

Not worth doing as a beginner who is imaging from indoors...

Please don't get a telescope because it seems like that's what you need or want! A 200p needs an Heq5 mount and is big and bulky and heavy. In fact, you would probably need a 200pds for imaging but that's still equally big and bulky! Even a 130pds is a bit on the bulky side. I have a 200pds and a 130pds and they both sit in the corner gathering dust. Make your astro life easier and just get a decent goto mount with a camera and lens! There are so many targets you can pick up with just a 200mm or 300mm lens. A bulky reflector is awkward to balance and the focal length means you have to guide and you really need an heq5 pro. Louise

Well... I'd say if you have a Canon (or other supported brand) camera which is able to pick up Ha (some do) and you have a narrowband filter, then you should be able to image Ha-emitting nebulas. If your camera can't pick up Ha but can be modded then it's worth getting that done. The example image I posted above was taken with a narrowband filter in Bortle 9 city skies. I do still get gradients caused by nearby streetlights but I can still get images. Louise

I would get at least a 600d and, if possible, an already modded one.

Hi there If you are sticking to a camera plus lens for the foreseeable future then you don't have to worry about arc secs/pixel. What you do need to do is study and research so that you understand, in practical terms, what you're doing and why you're doing it. As I mentioned, sticking to a short focal length makes astro imaging life much easier! The only thing you'll pick up with a phone plus eyepiece is going to be the Moon and some of the brighter planets. You need longer exposures and greater integration time for dso's. At the same time, you need very long focal lengths to get images of planets which are more interesting than small circles of a couple of mm in diameter. Integration time is often measured in hours for many dso targets. That can be something like, say, 20 x 6mins or 10 x 12 mins. If you do a 12 min (or more) exposure then you are risking something going wrong and the whole frame being lost. My favourite one (not!) is car headlights ruining a sub frame. It can just as easily be clouds, aeroplanes etc. The other thing is to use your camera tethered to a laptop/pc, and with a mains supply (only if you're indoors) or a converter from a 12V battery if you're outside. It's normal to use Canon's live view for setting up and getting focused. You wouldn't normally bother with the small camera lcd (well, I wouldn't). I'd also recommend getting a widescreen monitor to plug into your laptop (again, if you're indoors). It makes life much easier when you're running multiple pieces of software. Louise

Shaun: Well, from getting on for 6 years experience at imaging from my flat I can say I've mostly enjoyed it even though the limited view of the sky is frustrating. But, there again, perhaps not as frustrating as the lack of clear skies, the poor forecasts and the changeability of the weather here! I think if I were starting again but was still confined to the flat, then I wouldn't have bought all the scopes that I now have. Instead I'd maybe just get an EQ5 Pro goto (need a PC interface cable) and image with a dslr (or mirrorless) and lens - a 200mm one is quite good. Ok, it's not that much more for an HEQ5 Pro which is the much better mount but isn't necessary for short focal length setups - it would be overkill for a camera and lens. At the moment I have a Pentax67 format 300mm lens mounted on an eq3 pro and with a qhy miniguider. The lens does produce unwanted reflections so is probably not the best lens for astro but I got it cheap off Ebay! Anyway, the whole business of imaging is much more forgiving at short focal lengths! An astro modified dslr is best, or one that has a good response to Ha in the red (if you want to pick up the red nebulas). Some dslrs do, others not so much. It's a good idea to do research and due diligence before parting with any money on astro-related equipment! It adds to the cost but nowadays you can get dual band narrowband filters designed to pick up Ha (red) and Oiii (green) when using a colour camera. Disclaimer: I've not tried one myself but I've read some favourable reports - there are a number of brands - Optolong, ZWO, Baader, IDAS etc. Even with only a 200mm lens you may still benefit from guiding. A mini-guide scope, and guide camera add a fair bit to costs but, on the plus side, you could do without for as long as you can get away with it. You can certainly do without if you can keep to short exposures e.g. 30s - 1min, or so. I've improved my ability to point higher in the sky by either fitting shorter legs to a tripod or by using a shortish pedestal mount. Here's an image I took some years ago with a dslr and a 200mm F4 vintage Pentax Takumar lens (It was a 'monofied' and cooled Canon 550d). I think I must have had a Ha narrowband filter on the front of the lens. I would have used platesolving to centre on a selected star so as to get all 3 main components (M35, Monkey Head and Jellyfish nebula) of interest in frame. This image is probably cropped, and also resized to make it smaller It's just to show that you don't need an actual telescope in order to take ok/interesting astro images. You just need a good tracking mount and a reasonable quality camera - and those elusive clear skies, of course! Louise

Hi Shaun Yeah, you can take astro photos with just a camera and a short lens on a tripod but, in my opinion, it's a bit meh. If I were to try and do it here in Glasgow I'd get nothing! I have too much LP/skyglow to pick up anything but bright stars and planets with a few seconds exposure. You may be luckier! If you think about it, if you do 200 exposures of 2s each, that's 400s = 6min 40s total. That's not very much for all that shutter clacking! Anyway, you should download the proper Stellarium to a laptop/pc. Platesolving software is free but you do need a goto mount with a computer interface to make use of it. Have fun with the camera and tripod Louise