Thalestris24

I just bought a Tacklife rotary tool off Amazon to help me with some 3D printing post-printing tasks. Yep, (needle) files are useful too. Having a cfl bulb is useful for initial testing as well as a neon. Building the Lowspec was my first ever experience of tapping a thread - better late in life than never! 🙂 Louise

Meant to mention before, there is quite a bit of useful info and peoples' experiences of printing and using the Lowspec on here Louise

Yeah, filament comes in 1kg reels. I think my Lowspec 2 weighs around 500g including lenses and grating (it's actually 1.18kg with cameras and t2 tubes attached but my qhy183m weighs about 450g on its own). Exact weight will depend on the density you print at. How much you actually use is going to depend on whether you have to do reprints. I've had to reprint some of the parts 3 or 4 times... But I'm not an expert 3D print person! I was a complete 3D and slit spectrograph beginner when I started. Louise

PLA has been fine for me. I would advise: 1) Calibrate your printer 2) Practice bed levelling 3) Get familiar with your particular printer. Do lots of practice test prints of rectangular pieces with holes in them to check how they come out and to be certain your bed is level Hth Louise

Ok - excellent mount! It's up to you which guide scope you go for. The finder-guider is maybe better value but either will do the job. Yes - flex is your imaging enemy so always strive for rigidity! Louise

A 50mm guide scope is fine. Most guide cams have around the same pixel sizes so a fast 50mm guide cam is great. It gives you a wide fov and bright star images. If you buy a standard finder as I linked to, you need an adapter at the rear of the finder as you have to remove the existing lens assembly viz https://www.firstlightoptics.com/adapters/astro-essentials-sky-watcher-9x50-finder-to-c-adapter.html If you'd prefer your dedicated ED guider then you won't need that adapter. However, that guide scope has a slightly longer focal length so a slightly smaller fov. It's a personal preference which one you go for really. Btw, with a 50mm guide cam you probably won't also need the Telrad as you'll be able to use the setup as an e-finder. Which mount do you have? That's the most important part for good imaging! Louise

Ok, that sounds good. It can be better to have rigid mounting to ensure there's no flex between the guide scope and imaging scope. It doesn't matter from a guiding point of view whether or not the two scopes are aligned. It may be a problem if you want to use the guide scope as an e-finder. However, using plate solving via the imaging scope is becoming a more popular way of getting on target. Louise

The SW 50mm finder guider scope is excellent. In general, though, it's best not to use the finder scope bracket. However, you'll probably get away with it as your imaging scope focal length is short (also depending on which imaging camera you use). You'll need an adapter to fit the guide camera to the finder. Are you thinking of using the qhy5-ll as an imaging camera or guide cam? The qhy5 is essentially a guide cam. What targets are thinking of using your setup for? Louise ps I just realised you were considering the ED finder. TBH that's a bit overkill - the standard one is much better value though, as mentioned, you do need an adapter https://www.firstlightoptics.com/finders/skywatcher-9x50-finderscope.html

It's ok - I sorted it. Problem was caused by loose rollers under the bed. Thanks anyway 🙂 Louise

Maybe not completely out of focus but made worse by the reflection. I adjusted the focus and used a translucent plastic sheet as a diffuser. I think the focus is still off a bit. CWL? My focuser on the Lowspec is dreadful... I hate having to use it. I'll definitely have to reprint the slit assembly. I'm tired - going to bed now. Thanks for your help. Louise ps Working in my living room I can't keep dust out - can but try and keep it to a minimum. All the optics have dust on it...

I set the grating back to normal mode but it looks completely out of focus now. Surely it should still be in focus or close to it? Louise

I think this one is maybe a bit better. I took the slit assembly out. I noticed that when looking through from the illuminator side that the bottom of the slit was being cut off! I've taken the illuminator out so this image is without it. Bin 1 this time, just the illuminated wall, 15s. There is still a tendency to cut off the very bottom. It's looking like I'll have to try reprinting the slit holder body... Another thing I noticed from looking through from the illuminator side is that if tilt the assembly such that I'm not looking through the slit itself, I can still see the cfl bulb. Maybe this is what's causing the ghosting? Maybe it's not an issue with a less bright source. Louise

Oh, I see what you mean now. I mentioned I had problems with the slit to Paul earlier. Louise

Here is 30s exposure, bin 1 (cropped), 30s exposure As well as the ghosting/reflection there is an obvios difference between top and bottom. I'm wondering whether the grating is not vertical ie leaning at the top or bottom towards the camera. Louise

Hiya It's not stretched but it is bin2. I'll do another with a longer exposure. What does that mean - 'not aligned with the grating grooves'? Louise

Hi Ken Vignetting could be a problem - I'm not sure. I just took this image of the zero order (20um) from the camera. It shows up the reflection problem very well. Do you think it's something to do with the reflective slit? I've tried masking off both sides of the slit with some card but it doesn't make any difference. So it must be something else... Louise

Oh ok - I have the modified holes now. I've tightened/loosened the spring. The main problem is that I can't get a smooth movement. I count that as a small problem since I basically leave it on the 20um slit at the moment. Do you think I might have a problem with the slit illuminator part? I reprinted it to match the modified holes. I'm trying to take an image of the zero order at the moment but can't seem to focus on it - it's 'optically' rather distorted with ghosting even against just my illuminated wall. Something is amiss - I just don't know what. The focusing mechanism is very stiff which doesn't help. Louise

That's a very clean line! I'm envious... Is that also a 20um slit? How come it doesn't show the slit angled ends? (Clearly visible in mine). My holder mechanism doesn't always place the slit vertically and in the same/right place. I'll try imaging the zero order as well. Louise

Here is CFL spectrum, taken with the 183M, bin 1, 1s exposure, 20um slit. I think it's a bit sharper than before. There is still some widening / blurriness at the bottom (=top?), as seen above. Louise ps I've bought a Nitrogen spectral tube. I just need to put together a power supply to try it. I think they 'strike' at 2kV but I'm unsure what they normally run at. Maybe a fluorescent tube ballast could be used? I think they strike a 1kV pulse but then drop down to below mains voltages. If anyone has any experience of using spectrum tubes and knows how the power circuit works, please let me know!

I think this is about the best I can do(after tightening) though it doesn't look right, It seems to 'flare' towards one end - maybe that's to do with the light source - a cfl? Anyway, after dropping it again earlier, I have try and get the camera attachments back on the body... Louise

I've set up a mini guide scope and camera. This is the first slit image I took: Doesn't look good, and maybe overexposed. This is an image after attempting adjustment: Better? Adjusted focus and reduced exposure. I have terrible trouble trying to decide on focus or not. Any idea how I might get rid of the ghosting / multiple images? Is it caused by the reflective slit? Louise

Looks very unappetising to me! I cook mostly plant-based food but don't have any need to make it into shapes! Louise

Oh ok. I'll bear that in mind! Thanks Louise

I have a small 45 deg mirror that I made before 🙂 I'll try a finder first and see how I get on - I'd rather do that than hunting around for the zero order. Will post my result 🙂. Louise

Ok. Hmm... I'd have to take the grating out to do that - or maybe I could just use a mirror. It's 2:30 am here now so I'm turning in for the night! Thanks 🙂 Louise