SSI-Rick

Dear Steve: You asked about results and if they are working well. Coincidentally, I have just returned from the annual conference of the AAVSO in Tucson, AZ, where I gave a presentation on this very topic. I have attached a pdf version of my PowerPoint slides. They both perform very well, although it took a lot of effort to learn how to fine tune each of them. The LowSpec out performs the StarEx within its limits. The StarEx can accommodate a grating with 2400 L/mm, which will not work in the LowSpec. With the 2400 grating, the StarEx is theoretically capable of achieving an R value of over 30,000, although I doubt that I could ever actually achieve that. The LowSpec is a more complicated device to assemble and adjust, and the image in the guide window (using PHD2) is more distorted than it is with the same guide camera and software when using the StarEx. I think it has to do with the characteristics of the Jeulin slit disc in the LowSpec compared to the reflective properties of the Shelyak slit that I am using in the StarEx, but that is just a guess on my part. The slit from Shelyak is the same one used in the LHires III and the LISA. I'm close to being able to routinely produce spectra of a quality sufficient to upload to the various databases: AVSpec, BAA, BeSS, but still working on it. Rick Diz_Comparing LowSpec&StarEx.pdf

I have successfully printed two complete LowSpec units and two Solex/StarEx units plus spare parts with my Ender 3V2, and found that it was a matter of (painfully) gaining experience with what works and what does not. I upgraded my printer by replacing the extruder with a 'dual-gear drive" unit($15). This was the most important upgrade that I made. I consider it essential. The stock one would slip and not feed filament properly resulting in total failure of the part. I replaced the Bowden tube with one made of Capricorn PTFE with better heat tolerance. I tried an 'all metal hotend' and then took it off because it kept clogging. I installed a BL Touch level sensor for helping with the bed adjustment, but I am not sure that it was really necessary. I discarded the brass nozzle that came with the printer and used hardened steel of either 0.4 or 0.6 mm diameter. There have been lots of good suggestions about settings, etc. I found that PLA with carbon fiber prints very nicely, but there is the concern about thermal stability. So, I used PETG w Carbon Fiber, and found that a nozzle temperature of 245 to 250 C worked, with a bed temp of 80C. My printer has the Ender special glass plate on the bed, and I learned that it worked great with no added adhesion helpers as long as it was perfectly clean. At the start of each print I use isopropyl alcohol to clean the surface. A level bed with just the slightest distance (a sheet of printer paper can just be dragged without tearing) to the print head is essential for the first layer to adhere properly. When the part is done, if you let the bed cool down all the way to ambient temperature, it will release from the glass plate completely ... If you try to get it off when the plate is still hot, you will break something trying to get the part off. The printer must be calibrated as others have said, both in x,y,z dimentsions and for the extruder. There are YouTube videos that show how to do this. If all this works out, you grow to love your printer; if not ... Rick

Thanks a lot for the suggestions. Louise: I went back through the long dialogue provided here, and read with great interest your postings. I sympathize with the difficulties that you experienced, especially with your apparently not having a workshop and a broad array of tools at your disposal. It was quite helpful to me as I began my own 3d printing and assembly. I hope that it turned out well, and that you have a working spectrograph. Rick

I know this topic thread is old, but I thought I would give it a try anyway. I have built a LowSpec 3 and am now deciding how to attach my ASI camera to it. According to Paul the sensor should be 51 mm outside of the Lowspec body; and, the sensor is recessed 6.5 mm inside the camera case according to ZWO. So, that leaves about 45 mm between the camera body and the Lowspec body. Also, in order to orient the camera so that the spectrum is horizontal, you need to be able to rotate it once attached. And, the attachment needs to be secure and fixed in position. I can use a single or set of extension tubes with T2 threads, but then the rotation would end up simply at whatever point the threads tightened up. I hope I have explained this adequately to show why I am unsure of exactly what system to use to fix the camera to the body. Suggestions? How did you solve this problem? Rick (ps. I'm going to post this to other forums as well, in case you see it again somewhere.)