Thalestris24

But without the ball of wool at the top, I presume Louise

Ah cool! I was wondering, since Paul Gerlach's (daylight) sample spectrum was high resolution but limited wavelength range. Recording multiple spectra covering different wavelength ranges makes sense. I keep meaning to download BASS Cheers Louise

I'll probably just try a reprint. If it happens again then I'll fiddle with the settings. Do you remember printing yours - it's the part 13_focuser_slider Thanks Louise

I'll bear that in mind. I assumed a cooled cmos would be better. The 183M 13.3 x 8.9mm so just over twice the horizontal width of the 290M. Another option might be the slightly bigger 178M. I'll have to dwell on it Louise

It was printed as seen. I don't think there was any overhang but I had the slicer set to print supports. I thought having it set might have caused a problem. I'll try printing it again. Thanks Louise

Oh ok - small sensor though and maybe a bit noisy?

Was doing some printing yesterday... One piece came out a bit of a mess! I printed the piece on the right first - just towards the end it's gone a bit ball of wool, lol. I then printed the piece on the left - perfect! Any ideas what might have caused the problem? Could it be anything to do with 'supports'? As far as I know the top part should just be a plain hollow rectangle. Cheers for any suggestions Louise ps the top bit is higher than the piece on the left - could height be a factor?

Thanks for the tips! The above component is internal and purely functional. The hinges were nothing to do with me Cheers Louise

Hi Eric What camera do you use for acquiring the spectrum? Maybe my qhy183m might be a bit heavy to hang off the plastic case? It's otherwise a really good camera but a dedicated alternative might be better since I also use the 183m for dso. Louise

Thanks for that, Ken. I must get around to reading your book! It's patiently sitting on my bookshelf I tried a few calculations. It does seem that there is a trade-off between resolution and wavelength range. I don't know how easy it is to take multiple frames to build up a higher resolution spectrum in a similar manner to a mosaic of a dso? If not a 600 line/mm grating might indeed be a better option. There is the option, I think, of being able to swap gratings. I did some screen grabs of the summaries: First two are with the qhy183M: And with the KAF8300/383l+ Of course, when I get to actually trying it I'll have to see what I can tweak to get the best results for my kit, guiding, and skies. I'll look closer at the lens specs when I get the chance but don't want to change the basic dimensions or anything. Cheers Louise

Ok, cheers!

Maybe, but it's the same price. I'm not sure how much of the spectrum the Lowspec will be able to make available to the camera at any one time. Not sure which cameras yet. I'll probably try with a qhy5l-ii or minicam5s for autoguiding. Not sure what would be best for recording the spectrum but I've been using the qhy183m with the SA100 - it has a high qe. I have an Atik383l+ mono but it's a bit slow. Otoh, I'll probably not be looking at faint stars/objects so maybe camera speed won't be so critical. I'll have to play with it to get a feel for it. I have to get the Lowspec built and up and running first - that may prove a challenge! Louise

There was a different 1800 line/mm one but it became obsolete. There's also the lower res 300 line/mm alternative https://www.thorlabs.com/thorproduct.cfm?partnumber=GR25-0305 Louise

I believe Paul upgraded it to 1800 line/mm - this one . I probably won't get it cheaper than that Thorlabs one. I couldn't see an equivalent on Optometrics/Dynasil? I'm not sure that I'll achieve the high resolution but I'm aiming high! The Lowspec can alternatively use a lower resolution grating and I think you can just lift one out and put another (600line/mm) one in. Louise

It's not as complex as it looks! Honest! Louise

Yeah, the 1800 line reflection grating is ~£120 with vat, from Thorlabs. I'm not likely to find one at SurplusShed but there's no harm in asking! Louise

In case anyone is interested here's some images of spectra and the Lowspec from Paul Gehrlach's posts on the German forum: Daylight line spectrum in near IR The corresponding spectrum: The 3D Printed design of the Lowspec: I have quite a way to go with the build but have made a start! Louise

Oh, it took 2hrs 40min at 60% infill, 0.1mm layer height, I think. It's done now, so no worries Louise

Hi Um, what part are you referring to? Louise

Yeah, I'll drop them a line tomorrow and see if they can supply any of the lenses (or ones that are close to the spec) on my parts list. If the postage is reasonable that would be good I'll ask about diffraction gratings as well. Louise

I think optically there is some leaway for the lens' focal length and diameters. Might have to print some different sized holders. If I can get them cheap, I'll try some that are close to the design values. If the worst comes to the worst, can get the expensive ones from Thorlabs. The total cost will still be a lot cheaper than a purchased spectroscope. Louise

Nah, just a couple of mirrors, a couple of lenses - and a slit One lens is for the autoguider, one to collimate, and another for the camera. Simples. Louise Plus a diffraction grating, of course

Ok, cheers. They sound similar to AliExpress. Louise

How much do they charge for postage? Did you have to pay import duty/vat? I think the cost of a few lenses should be below import duty charges - hopefully! Louise

No eyepiece wouldn't do, I don't think. The design essentially calls for single, unmounted doublets that can be fixed to lens holders: Surplushed a possible - similar to AliExpress Thanks Louise