ollypenrice

I removed only the diagonal, Stu. There was very little room for padding in the box I made, especially at the ends because length was the issue, but I carried it onto at least four flights. I reckoned that, since it would be with me all the time, I wouldn't need too much padding. My first view of the Rosette was with that scope, in the Spanish Pyrenees. I could never see it in the UK. Olly

I think Andrew has resolved your problem of curvature and perceived force. The tidal 'forces' only appear because parts of the moon encounter resistance from other parts of the moon because they are trying to fall at different rates. (I think?) Regarding force, I found this analogy entertaining: two (flat earther ) pilots set off simultaneously from the equator 500 miles apart and fly at the same speed and the same altitude, both using navigation systems which keep them on a course scrupulously perpendicular to the equator. They are astonished to find that, about 12000 miles later, they have collided and have to bale out. While awaiting rescue on the north pole they earnestly discuss what mysterious force caused them to converge... Olly

A travel scope to look out for is the early F5 TeleVue Genesis. It's very short. I made mine a dedicated box which met the requirements of cabin baggage so it was airline friendly. You get 4 inches of aperture and optics which, while not perfect, can take you from 15x binocular fields to 200x planetary views which are very respectable. Short of an AP Traveller, which you won't find for the £800 or so commanded by an old Genesis, I can think of nothing better. Olly

My instinct says the opposite but I've never tried to make anything which mounted a scope on wheels so I'm left only with instinct. What about trying it on wheels but having hinged bolts fixed to the deck which pivot up to pull down on the trolley top once in position? Olly

It is probably moisture so leaving it in a warm dry environment for a few days might sort it. It doesn't look very healthy 'as is.' Olly

7 out of our 23 hours were spent on Ha when Tom and I did this one. It's time well spent and really picks out the spiral arms. Olly

My Pronto was about £200 on here. Olly

Although they are expensive, genuine down duvet jackets are incredibly warm and very light. Also remember that vast amounts of body heat are lost through the head and that the only part of a warm boot which really matters is the sole. Taking a piece of camping mat outside to stand on is a good trick. Olly

The key thing in this design will be how you go from 'wheels' mode to 'standing on the deck' mode, especially in the case of the equatorial. I would be thinking along the lines of a lever and cam system either to raise and lower the wheels or to raise and lower hard blocks which lifted the wheels off the ground. Operating while riding on the wheels wouldn't work, in my view. This might sound complicated but I don't think it need be. Ideally the operating position should be built in to the deck, just a simple locating system which would give you an acceptable PA without the need for nightly adjustment. Olly

You can also take a couple of nails and clamp them vertically in a vice at the same separation as the holes, hold the stuck ring down onto them, and turn it to free it off. Those holes are very good news! Would that every ring had them. Olly

I think the image is very good. Could it be a tad tighter? Hard to say. I think the guide RMS is rather high if it's around an arcsecond but it should be OK for the image scale. Focus? Again hard to say. It might be a question of seeing. Ours has been poor of late and others have found the same. I'm not a fan of the Moonlite focuser for imaging, I must say. It's quite prone to slip since it has the roller driving the polished anodised drawtube, which is a not a good idea. Most experienced users of imaging Newts suspend the camera beneath the tube (ie in the lowest possible position with the scope pointed at Polaris.) This requires a truly non-slip focuser. Olly

Those are excellent values. Olly

Plus or minus 10 arcseconds under guiding would be a total disaster. I'd consider that, under guiding, anything greater than an arcsecond RMS would be unacceptable. Mesu claim 4 arcseconds peak to peak unguided. Olly

It's a very good pier but one thing tends to come up on these threads: you don't need to level the pier top so the threaded levelling bars are not necessary and add complexity and expense. Then again you do need a nicely machined top plate to sit the mount on, of course. But, for the record, GEMs can be perfectly polar aligned on non-level pier tops. Olly

I'm another in France, in the normally sunny south east where Provence meets the rising Alps. It has now been raining for three weeks! Well, not non stop. We collected about 30 hours of deep sky data in the last fortnight but that's way below par. Welcome. Olly

If I've got this right a 135mm lens with the 1600 CMOS chip is working at about 5.8"PP which really needs a tracking accuracy of about half that, so around 3 arcsecs. If this is so it isn't safe to assume that + or - 10 will be OK. The thing is that pixels are now getting so small that old rules of thumb regarding focal length and resolution are becoming out of date... The day may come when we need to guide at 50mm! Olly

Great result on a more than tricky target. It's about the same size on the sky as M101 so the fact that it is so little known indicates that it's very good at hiding! Olly

Apparently they are 11 lightyears long... A fine image. Olly

If you have Photoshop or equivalent you could, if you wished, get this even closer to natural colour by going into Selective Colour. You might not want to, of course, but it can be done.

That really is very good! Splendid image scale. Olly

Certainly a great combination of lens and camera - plus sympathetic processing. Olly

It's a long time since I could run like that guy! Olly

I've just received a copy of the Dutch Astrofoto Bulletin which features one of my Astronomy Now articles - in Dutch. Rather exciting. It was translated by our regular guest Frans Kroon and permission for publication was kindly provided by Astronomy Now's editor Keith Cooper. When it came out in English I was half expecting flak from it since I essentially argue that a 6 inch refractor can run much bigger reflectors very close in DS imaging. I now have a second opportunity to be mauled by angry reflector owners... lly

Certainly, and I want to be clear that I'm only discussing my old mount now because I was asked to do so. If SW have sorted it out, as it seems they have because Sara is another exacting but happy user, then that's great. I think what so irritated me with my early EQ8 is that SW stated categorically that the Dec mesh was adjusted by hand because there was there was no spring loaded compensation. That means that they must have been perfectly well aware that the mount was binding on one side and rattling with backlash on the other, yet they sent it out anyway. As a result I spent two whole days unboxing, assembling, dismantling and reboxing the mount. If my 14 inch Meade LX200 mount expires, as they sometimes do, I'll almost certainly buy an EQ8 for it. I'm not hostile towards the present EQ8 by any means. Olly

No, if I locked the clutch at one position of the wheel on the worm I might have either backlash or too tight a mesh. If I released the clutch, moved the Dec housing and re-locked the clutch nothing would change. But if I drove the wheel 180 degrees with the motor I'd get the opposite of what I had before, so backlash would turn to binding or vice versa. Moving the Dec housing manually by unlocking the clutch had no effect on whether I had backlash or binding. I think you may be using the wrong term when you say 'spur gears.' For the problem to arise over a scale of 180 degrees in Dec the problem has to lie with the worm and wheel. Spur gears are like this: https://www.indiamart.com/proddetail/spur-gear-15890246548.html Olly