Thalestris24

Oh ok, thanks Ken! I knew there had to be a way of doing it as lots of people seem to use cameras with smaller sensors. I'll give it a try sometime this week 🙂 Louise

Hi I'm thinking of swapping over my Atik383l+ with a qhy183m. The Atik has been driving me nuts - it takes about 12 secs to download a full frame so trying to focus it, is difficult and frustrating. The 183 has a smaller sensor so won't cover as much of the spectrum in one go. The big Atik covers 4037-6963A, the 183 only covers 4416-6584A (SimSpec v4.3). But the 183 is a lot more sensitive, lower noise, a lot quicker - and a lot quieter! Am I right in thinking I'd just take two exposures with rotation of the grating position using the micrometer? Plus calibration exposures for each position? Presumably I'd also have to adjust focus for each position, but maybe that's really a good thing, if a bit of a pain. Louise

Does it show up in device manager? Try reinstalling Canon Eos utilities.

Hi again What computer, Windows version and cable are you using? Make sure your usb cable isn't too long, is shielded, and is making good contact. If you have a short usb 2.0 cable then try that. Make sure the camera mode button is set to 'M'. I don't know the 450d - check any other settings on the camera you need to have set. Is it working ok with the Canon EOS utilities? If all else fails, try posting your problem on the APT forum. Good luck! Louise

Maybe try changing the setting in APT to not connect automatically. Sometimes it's worth powering everything down and doing a cold boot. Louise

Yeah, most likely a connectivity, camera or power/battery problem. Avoid connecting via a hub if you can. Also, can be best to stick to usb 2.0 at the computer end. You can double check connectivity with Canon or Canon compatible software though I'm not specifically familiar with the 450d. Louise

It wasn't glued - since I'd had so much trouble with the threads. It is glued in place now! If I were building it now I'd use a metal t2 insert. I've had trouble with the slit holder also and wondering whether to reprint it. It's difficult to keep the slit aligned. At the moment I can't get a sharp focus - not sure if that's something to do with the slit. The camera is ok. It fell out of the scope because thumbscrews on the scope must have come slightly loose. I'm double checking, now, when the Lowspec is attached. Louise

Yeah, I think because it's sealed the measured humidity will rise with temperature. I think the whole idea of 'humidity' in this context is what it is as applied to the atmosphere, which is clearly an open system. Louise

I've had enough trouble just trying to focus mine manually... Also, was testing it out last Friday and had a bit of a disaster. The whole assembly fell off the scope and crashed to the floor 😮. The Atik broke off (the pla T2 insert came out). I put it all back together ok (though it's now nicknamed 'Humpty'). I couldn't get a spectrum out of it It was only later that I realised that the grating assembly had jumped out of place. Fortunately, it was easy enough to push the grating assembly back in place but I've had trouble getting a sharp focus on a starter bulb. I have recorded spectra of the cloudy sky, the Moon and a floodlight. Will have a go at processing them in BASS Project when I can. Louise

The guided performance of the heq5 with a belt mod is much better than that of the AVX. There's no need to use Synscan when you have computer control. The mount control via usb is basically the same between the two mounts. Plus the Heq5 is supported by eqmod. Louise

I have both the Heq5 (belt mod) and the AVX - the HEQ5 is a much better mount! I use both via PC and effectively without the hand controllers. I have to use the AVX hand controller to interface to the PC with, but not otherwise. Louise

I just braved the windy gusts to do some shopping at Lidl. #intrepidme #raiderofthebusyaisles Louise

I think the shift can be quite noticeable (without a diffuser). Clearly, if both electrodes in the bulb are glowing then it could appear as two sources with light hitting the slit at different angles. I'll try and sort out some sort of diffuser for mine Louise

I've noticed that too and realised I need to make a holder for it that fixes its position (something I still have to do). It's probably an effect linked to the variable spread of the source close to the slit. I've actually been using a Sylvania 70W starter bulb which is bigger than the Relco. The Alpy calibration unit has the bulb fixed in place and I think uses a DC power supply which will only cause one side of the bulb to glow. I had thought that wasn't such a good idea but now I'm not so sure.... Louise ps it's a good idea to use a reflector - I just have some Aluminium foil wrapped around mine. There may be a better way...

The sensor back focus won't be the same. If you have a reducer you'll probably have to insert an extension tube. Always a good idea to get close to infinity focus during the day with a new camera. Louise

Alas, thick cloud, wind and rain here as Storm Ciara rolls in... Batten down the hatches! Louise

😄

It occurred to me than a small EL panel might do for taking flats with, so I ordered a white 5cm x 3cm off Ebay. I'm not sure what the spectrum will be like but, since it's a white panel, it should be broad. It might be possible to fit one inside the Lowspec case else maybe in a filter drawer/changer which are ~5x5cm. I ought to be able to simply switch between the output from an EL driver to either the starter bulb or the EL panel. I've no experience of using EL devices so it should be interesting to investigate, if nothing else . I don't know quite how bright they are. If they are quite bright then maybe could simply fit one to the floor of the case? Will have to experiment... Louise

I just ordered a couple of the EL drivers. They are ridiculously cheap - 2 for £2.30 plus free postage from Singapore, lol. I wonder if the Alpy design with the mirror is protected? If not, I guess it would be fairly easy to do something similar with a mirror. I'm not sure why they've used a halogen bulb for the flat field source, I'd have thought a white led would do, though I'm not sure of the spectrum you'd get. Louise

It may use a DC-DC converter circuit similar to what Dr Jolo has posted. The DC-DC boost circuits use a small inductor rather than an actual transformer. The EL driver I linked to has a 120V AC output - it's also very small (4 x 1.8 x 2.3cm). As it's only 120V it's safer (though could still give a noticeable jolt!) and may be ok to run a starter bulb without a resistor. Louise

Yeah, one of those would work to generate the voltage. The only trouble is that it's a dc-dc converter which means that only 1 half of the starter bulb will light which is why I've steered clear of them. That may not be a problem in practice, I'm not certain, but it may affect the life of the bulb and may affect it's behaviour. Certainly worth a try! Louise

Actually had some clear sky tonight so had another go with the spectrometer but didn't achieve much. I'm not sure my equipment or location are really suitable for doing slit spectrometry . I basically had the same problems as last time, made even more frustrating by usb problems and things disconnecting - grrr! Running 3 usb cameras concurrently is quite demanding. As before, I had trouble getting stars in the guide cam fov. I had to mess about pretty much trying to guess where a star actually was by using the Celestron driver arrows to move the scope this way and that. Then, if I got a bright star in the fov and then on the slit it was too bright to guide on and there weren't any others around to guide with. PHD2 seems to blank out dimmer stars when there's a bright one in the fov. Is there a way to circumvent that? Doesn't seem likely. I tried to acquire a spectrum of a bright star (Alphecca) unguided but nothing came out on the Atik383l+ even with binning 4x4 and a 90s exposure . I say nothing, but stretching the image did reveal a faint horizontal line and a short vertical one too. The Atik isn't very sensitive… I was a bit concerned when testing with a starter bulb as even that took 90s to get a decent image. What would anyone else's typical exposure time be for a single frame on a brightish star? I think my only way out of these problems would be to get new cameras but that would be rather expensive. Louise

Hi Paul I guess that Richard Walker inverter (see doc below) is about the simplest though you'd have to build it. As far as I know there aren't really any commercial very low power inverters around. At least, I've not come across any and there's not going to be any demand for them. Having said that, one of these electroluminescent wire drivers might work. They take in 12V DC and output 120V AC so should do the job. I suppose they actually do come under the definition of 'low power inverter'.... Anyway, they are quite cheap Maybe try one out? inverter-12v-dc-_-230v-ac-3.0-englisch.pdf Louise

* e-finder

I'm wondering whether to splash out on an alternative guide cam - maybe the qhy5ii, though it's not as sensitive as the qhy5l-ii, but it would give a bigger fov of the slit plate. Also, next time I'll try and remember to bin the efinder 178. Louise