DaveS

Brilliant image Haim. Do professional astronomers own the telescopes they use? Very rarely, do you know how much a 10 metre telescope costs? If it's OK for them then it's OK for me. Oh for some *truly* dark skies. I think I would be frustrated on coming home from a holiday in Namibia. My skies are fairly dark (SQI 21.66) but Namibia is in a different league, and would make me dissatisfied with where I am. It would be different perhaps if I still lived in London, at least there I *know* the sky's rubbish.

As you're right up against your boundary, note that "permitted development" regulations will limit you to a total height of 2.5 metres above ground level. Where ground level is in your case could be a moot point

I wasn't talking about dobs. I'm nearly 100% imaging, and looking at the OP's equipment list I'd say imaging was high on his priorities (Sorry if I've misunderstood this) so I was answering from an imaging perspective. The Serrurier Truss does have many advantages, but as Olly implied above, must be correctly designed, and not just to look "cool".

A GSO 12" Truss RC comes in at 24 kg, A GSO CF tube 12" RC is 18 kg, and my ODK12 is 19 kg, so there looks to be a weight advantage to a solid tube design. I'm not sure about the GSO, but the ODK has three fans for ventilation.

/ Wail "But we'll all be murdered in our beds" /Wail

Sorry for hijacking your thread Chris. I watched your vid on my 'phone and it looked better, though the "Ark" showed the macroblocking, probably the compression engine didn't have enough detail to push the bit rate up. Never mind, it was very enjoyable with much to ponder. Pity though, that you didn't capture anything at Astrograph, I particularly wanted to see if they had the Planewave mount there. Seeing the Rainbow harmonic drive mount was interesting.

Avid Media Composer But I'm still running a very old version (6.5 I think) I may still have an 8. something that I haven't installed yet. Boris FX Again my version is very old Smartsound Not bothered to upgrade as teh 5.3 I have does what I need.

Ah. It's been a while since I did any, even halfway-serious, video work, but I used to edit in Avid (Media Composer in the end), export as a QT Reference file and compress in Sorrensen Squeeze (Various versions, now up to 11). Loads of options there. I still have all the software on my office computer, including Boris Continuum Complete, DVD authoring and Smartsound Pro.

Couldn't watch it on my computer / screen as I got loads of macroblocking that I found very distracting, probably just my ancient lump.

Do you know how much 3nm Astrodons cost? . Possibly a Star Analyser to get started with spectroscopy? BTW I have a full set of the 3nm Astrodons, and find the [NII] very useful.

Yup, diffraction around spider vanes will be wavelength dependent, while a B-mask is, of course, a coarse diffraction grating. Most obvious with NB filters, but also seen in RGB. A mono camera will show the L as a single spike, but I guess a colour camera (Which I haven't used in years) will show a rainbow of multiple diffraction orders. Each dot ina B-Mask pattern is a different diffraction order.

Imaging any galaxy from a Bortle 8 location is an uphill struggle (I know. Before I moved here I lived in London), and M33 is of surprisingly low surface brightness, so very well done for imaging it at all. Even more so for overcoming so many firsts.

Ooh, lots of lovely big HII regions there, wonder what's been stirring it up?

Will definitely maybe try to attend next year, gutted (To say the least) that I missed this year. Given the journey time I may well book into the lodge and make it for both days.

Be careful of the Astrodons in the 8 position wheel. Although I have successfully run them in the 5 place wheel, I have read here that the 8 place is slightly different, and that people have had trouble with them.

Off to pursue my designs by myself.

This very clearly shows the "blue bloat" that is the bane of the imager's life, especially with less than perfect correction. since I wish to keep the design mechanically simple without having to either refocus or move the grating I will look again at off axis paraboloids. And since this thread has wandered away from littrow designs into the lospec spectrograph I will leave it too.

i have just seen the SNo for the Acronis, printed on the reverse of the envelope the CD came in, but it's in such tiny figures, and so long that it will take me a while to type it in, especially as I easily transpose numbers.

I think my nearest streetlights are about 4 miles away .

Well, I've just sent in my first submission to AN. After the generally favourable comments it received I sent my 17 1/2 hour bash on Deer Lick and Stephan's Quintet.

This Autumn has been atrocious, even the MO recons that rain and cloud have been well above average. I think I had a clear patch a couple of weeks ago but will have to check my files.

Good luck with the jungle clearance Nigella I did something similar last year moving from Bortle 8 in London to the dark end of Bortle 4 in Dorset, but still haven't got my obsy built, though it's scheduled.

I've seen harmonic drive mounts on another site (Which I won't name) but they're rather pricey, will be interesting to see how these compare.

*tips drool out of keyboard*

I did a few "sums" and it looks like a 300 l/mm grating in the first order will put the range from 400 to 700 mm on the ASI1600 sensor with the Ektanon. However I think this would be a waste of a fine lens, and a waste of sensor area. Am now looking at options for an ASI183 with its narrower, higher pixel count sensor with a theoretical resolution of 2,800. I may reserve the Ektanon for something a bit wilder later, thinking Eschelle. Thorlabs do some 25 x 50 mm eschelles that look doable. Of course, beyond even the Eschelle spectrograph we get into the real head-banging territory of the laser referenced interferometric spectrometer and FFT analysis. No, I'm not going there, least I come back in a canvas jacket with very long sleeves.