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I've been following V694 Mon at high resolution (about 13000) during March. I did not notice much change in my spectra from early March, but I did notice the change seen by others when I obtained a spectrum on 31st March. A deepening of the H-alpha absorption at shorter wavelength / higher velocitie...

All, A clear night tonight so I've been able to spend time focusing the collimator lens and telescope following my adjustment to the grating holder a couple of days ago. The results are a huge improvement over anything I've been able to achieve before. Below is the best spectrum I attained. Most of ...

Francois, Thank you for your detailed reply. I think I may have just identified the main problem, which was the grating clamp was too tight and giving a slight deformation to the grating. This combined with my misunderstanding of which screws loosen to adjust the pressure holding the grating in plac...

Ken, Yes, everything in good focus with no compromise, guide camera focused on slit, telescope focused to give a nice star image in the guide camera, and neon lines focused. Just to emphasize this was with a different grating, the 600 l/mm grating. When I switched back to the 2400 l/mm grating the i...

Thanks Robin, Franck and Mike, I've not got to the bottom of the problem yet, but I think the best candidate is pinching of the grating. I have tried to loosen the grating holder for my 2400 l/mm grating, but no matter how hard I try I cannot loosen the screws and I risk damaging something. I did sw...

Hi Franck, Thanks for your post, which is very interesting. Here is a photo of my 2400l/mm grating, and it does appear as though the grating may be under pressure at the edges. I'm not too bothered, as long as I can find the problem and fix it. 2400_Grating.jpg I've emailed Shelyak to see what they ...

Hi Ken, That is actually what I did in my last post. I focused the spectrograph collimator to give nice sharp neon lines. I then did not touch the collimator again, taking the 2 sets of images with the only difference being the telescope focus. I am really baffled. It may be some I am doing wrong bu...

Hi Ken, Thanks for your reply. Trying to focus the telescope with sharp neon lines is actually what I have previously tried many many times, but without ever being able to achieve a nice sharp line for the stellar spectrum. The best I can get is what I've shown as position 1. I get nice results from...

I am seeing a similar issue with my Lhires III. The best collimator focus for the neon lines appears to be different to the best focus for the stellar spectrum. I wonder if this is what I would expect to see if my imaging camera position was not at the correct distance? I'm reasonably confident that...

I just received the following email from Jeremy Shears about a relatively bright (mag 11.9) probable cataclysmic variable that has been alerted to the BAAVSS forum. It is beyond my reach as I'm in high resolution mode with my LHIRES III but this might be of interest to others. "Not sure whether...