ollypenrice

That's a nice method. Ps has so many ways of doing the same thing. You can also click to activate your chosen channel and 'Save as,' giving it an appropriate name. It's always interesting when you find that someone uses a different method because it may lead you to new ideas. Olly

I've taken five of the courses run by the UCLAN consortium. I began with the Introduction to Astronomy and in following years did History of Astronomy and Cosmology. I then did the one year Radio Astronomy course with Jodrell Bank under the UCLAN umbrella and a shorter course in Galaxies with Liverpool John Moore's. I think all of these were excellent and, being a teacher at the time, I guess I was quite a critical student. My final course was Sun and Earth Climate. I didn't find this to be as good as the others but it still had its merits. I wouldn't hesitate to take more of these courses were it not for the fact that I no longer live in Britain so they would be vastly more expensive. When I did them they were almost absurdly good value. Recommended without any hesitation whatever. Be warned that I think I finished the last course in 2004 so I can't claim to be up to date! Olly

This kind of nonsense is utterly maddening and you have my sympathy, Helen. Personally I never change anything, under any circumstances, when a setup is working. If I wanted to introduce a new camera I would introduce a new PC for it because I don't trust the software to cope with a change. Olly

Well done! Not easy at the best of times, this one, and certainly not under a misbehaving sky. Olly

Yup, it is possible to build mosaics using fully processed images and sometimes you're inclined to do this because you have a nice finished image which you'd like to extend outwards into new tiles. I've been in this situation plenty of times and have muddled through - but it is the hard way. The easy way is to build the mosaic from the linear tiles. Olly

Well, it was 'Bolton, Lancs' when I were a lad but now it's in Greater Manchester. It's quite a big town. Lord knows how they moved it. Olly

The accent bugged me as well but I shouldn't have struggled since it turns out that she went to the same school as I did. It's in Bolton. Olly

I made the suggestion because an increasing number of guests using our observing sites for their own equipment use this system nowadays. Old muggins here is the only one outside! Olly

I was being a bit careless in my wording. What I meant was that, even in smaller telescopes, the chips available will struggle to fit M31 without cropping. Also most smaller telescopes (indeed most telescopes) struggle to cover a full frame chip. The image you posted shows that both ends of the galaxy have been cropped and that's not the deepest M31 that it's possible to take. Below you can see that quite a lot is excluded by your frame simulation. Olly

Is all this cabling necessary? Couldn't you just put power into the observatory and run the imaging rig on a PC located in there. I would go for a basic old desktop machine with plenty of USB ports, probably bought 'reconditioned second hand.' This should eliminate hubs. (I host six robotic telescopes and we have more trouble with hubs, either astro-dedicated or normal, than with any other product.) You could then control the observatory PC from the house via Team Viewer or Any Desk. Although you need two computers to do this I think it would be cheaper and, possibly, more reliable than the long-cabled alternative. Olly

Exactly, and there is an irony in this. The original purpose of guide rings was to allow guidescopes to be moved off axis in search of a star, whether for manual guiding or via old, insensitive autoguiders. Now people buy them in the mistaken notion that it's important to align the guide scope on axis. In fact the only real necessity is to mount the guider rigidly and guide rings offer a very poor way of doing so, as you say. Olly

As a natural colour imager constantly fighting green noise I, too, really struggle with it. Planetary nabulae can be green but really it just doesn't usually belong in the sky for me. Olly

I agree with the guidescope mounting advice. There is no need to worry about aligning it to the main scope. Make sure the whole focuser assembly is tight in the blue tube and that the focus is locked up hard. It's an excellent guide scope. We have two here. Personally I love Atik's Artemis Capture software which will have come with the camera. If you're new to imaging, read this: https://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html And this: https://www.firstlightoptics.com/books/dark-art-or-magic-bullet-steve-richards.html It's a nice setup. Olly

Your point about the cost of filters is valid but let's not perpetuate the myth that OSC is faster than mono. It is about 20% slower in basic broadband imaging and way, way slower than that in narrowband. If you take a deep M31 you won't fit it on any chip in regular amateur use. Using our full frame (36mm wide) Atik 11000s at 530mm focal length it still needed two panels. The deeper you go the bigger it gets! Enjoy the new camera. Olly

I think you could push a little harder! Olly

Agreed. Olly

If you're hand holding, the usual rules apply. For me that means 10x max. I'm not convinced that very light weight helps with holding. I feel that you need a certain amount of 'anvil effect' from the mass of the instrument to keep it still. Olly

Indeed it isn't. It seems to be quite outstanding. Olly

Competing with TEC doesn't just mean trotting out a list of words, triplet and apo etc., or a list of numbers 140mm, F7, etc; it also means building a reputation for quite extraordinarily high standards of quality control and consistency at a competitive price. Remember, there are telescope makers who are far more expensive than TEC and one of them, at least, has lost the ability to compete with TEC on QC or consistency. I see the Tak TOA150 is listed at 41 euros shy of 15000 euros at my 'local' dealer. You could buy two TEC 140s for that and have change to buy a second high end CCD for a dual rig. Dual TEC140 imaging rig versus single TAK 150? I know which I'd choose. I bought my TEC second hand a long time ago before there was even a UK importer. I paid £3800 for it with rings and Scopeguard case. It stands alongside my Mesu 200 mounts as the most unambiguously outstanding product I've encountered in astronomy. I'm beginning to sound religious: I'd better stop! lly PS I heard it described on CN as 'A glorified achromat.' Heh heh. Alnitak? Sorry, no further comment!

That's lovely. Luminance would help with the dusty features. Olly

It's certainly a classic!

I think the picture in question is very well known and probably hasn't done much for Zwicky's reputation. A link does not infringe copyright. Might it be this one? https://www.google.com/search?q=fritz+zwicky&rlz=1C1CHBF_enFR821FR821&sxsrf=ACYBGNRzCKp2s9Xxko6_x1a06zff9_3Z_Q:1574619720277&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiH-9TIu4PmAhXwDmMBHcRvCe8Q_AUoAXoECBMQAw&biw=1536&bih=750#imgrc=4g2nFfpakmssKM: Olly

Tremendous! I need to read through your method for adding the OIII data because I think you've got more out of it than I did. Olly

I think you're far better with a truss in large apertures because of tube currents and cooldown. I had one here in dry, dusty conditions, on a gravel observing site, without any issues at all. I can't agree that tube Dobs have a tube current advantage over truss designs because they trap the considerable thermal mass of the mirror in the tube. Although people are reluctant to do it I think research shows that fans blowing across the mirror are the most effective for breaking the boundary layer above the glass. The proper Serrurier truss is also very ingenious because it is designed so as to keep any flexure in the least harmful plane. If it moves it does so while keeping the top and bottom sections parallel with each other. Ours was never moved once we had it installed and once it had settled down it held collimation unbelievably well. Olly

I think that anyone who stops being highly critical of their own images will cease to be a good imager. Indeed I'd go further: I'd say that the most important evolving skill is seeing what could be better. Finding the problem is harder than finding the solution, in general. Olly