Horwig

To my west, in next door's garden is a huge tree that I've been cursing forever It really limits my imaging to the west, which is by far my cleanest sky. Today was a big day: GOING: GOING: GONE: Now all I need is a clear night Huw

Managed this last week over three nights. Very late in the season, there's a tree in my neighbour's garden on my western boundary which is just in the wrong place, so I was getting only a few hours a night before I lost the target in branches, so I binned everything to get more signal. Anyway, excuses over: 40 cm f3.6 scope, QSI6120 camera 100 minutes L in 5 minute subs bin 2 18 minutes each RGB in 2 minute subs bin 3 60 minutes each Ha and O111 in 10 minute subs bin 2 I'm so happy to have something to post, cloud and rain are so boring. One piece of good news, my neighbour has had a tree surgeon have a look at the offending tree, things might be looking up. Huw

Thanks Vlav, I've got a pair of scopes to pair it with, both would cover it well, a 0.72 reduced FSQ106, and a 40cm f3.6 Newtonian. Huw

I've been reading such good things about this camera, it's got me twitching my wallet finger. Trouble is, I've got two exceptional CCDs already, one a large target with big pixels, the other a small target with tiny pixels. The way I see things is that this would give me both in one rig, and with higher QE to boot. Question is would I see the difference in QE as less noise per hour of imaging (and that's important for imaging this far west, believe me) Also, would buying a CMOS now be too soon, I hate being an early adopter, having done it before with equipment for work. But, against that, if I sold my present cameras now, It would go quite a way towards funding this, If I leave it for a year or two, would CCDs be worth anything? Also, what would be the differences between the ZWO and ATIK products, specs look virtually identical Please, could anybody help me see reason here. Huw

This is a quick and dirty survey of sorts, but reading through my copy of this month's Astronomy Now, I noticed that not one deep space image in the 'Gallery' section was imaged from the UK. This reinforces my view that the last year has been pants for imaging, but It also made me think, if nobody's imaging much, they are not going to invest in new kit, so how are the astro retailers going to survive? Just my musings Huw O

Wow, what depth in 5 hours, is this the 105 f1.4, do you keep the lens wide open , or shut down? I'm just starting a widefield run on this target myself tonight, between clouds☹️ It won't be this wide, just 5x3 degrees Huw

Very nice work, they look just the job. Huw

Very nice and smooth, lots of integration time pays dividends. Huw

Thanks all. What I'm seeing is the deeper detail in the first image, that has 10 hours of L data and the wide one only 6.5 hours. It's either that or my differing processing between both versions. Huw

Thanks for the kind words, I've spent so long trying different versions, I'm not sure of anything anymore. Huw

I had a strange night back at the beginning of the year, it was clear! So out came the kit, cobwebs blown off, computer persuaded to talk to everything, and as they were high in the sky, I decided to revisit the Pleiades. I'd imaged them last at the end of 2016, and had two clear nights in a row, but the resulting image was pants. I blamed the data (could it be my inability to process? No, why would it be 🙈) After analysing this new data, the night had not been that great, lots of thin cloud, not enough to disturb guiding, but enough to give quite a few low contrast images. I decided to go back to see if I could combine the best of this new data with my stuff from 2016, and this is the result. The camera angle was not the same, so some cropping had to be done. (sorry for the long preamble) Having looked at the old data, there seemed nothing wrong with it, so I processed an image with just the 2016 data, which naturally has a slightly wider FOV: Can't decide which I like the best, any opinions? Huw

If you can't find a suitable wall Adam, might I offer you mine😉 Huw

just one word:: SUBLIME Huw

I gave up on the yoga mat quite soon. I do imaging from my garden, which is very dark, but the light blue yoga mat would reflect any lights into the optical train, far from ideal. I now stick to matt black Huw

True, I've been trying to attack this itereratively, and it;'s sort of working. My latest challenge is a problem thrown up by the high res encoder on the polar shaft. The dc gearmotor is mounted to the worm block plate by its face plate, trouble is, under drive, the 3.5mm ali plate flexes, just a little, but it's enough, the encoder on the motor, and the one on the shaft fight, and an error of an arc minute or so throws the servo controler into a tiz, it tries to correct, and results in a 4 arc second bump, every few minutes, and yes, at 0.4 arc seconds per pixel, that's a lot. It's too cold and damp here to start diss assembling the mount, it can wait till warmer weather returns. I'm interested in your idler wheel tensioning the belt, is it adjustable, and if so how? Huw

Nice one, battleships were produced with lighter stiffening😀

Just a thought Rusted, is any of the movement you were showing in the video due to movement in the bearings on the axis? My mount, as was, had pillow blocks without any preload applied, and I was getting appreciable sideways movement of the shaft. I've replaced them on both axes with pre-loaded taper roller bearings and precision cut shafts, that, and the work on the worm block hinges solved the wobble for me. H

the £800 is the cost of the encoder only (from memory), Sitech II is 900us, motors new about 150 us each, I got my motors second hand off ebay. Huw

Arc seconds per pixel

This might be getting OT (😀) My mount is controlled by a Sitech II system, using dc motors with encoders. The beacon Hill RA worm has 'wonderful' periodic error, so I've mounted a second hi-res encoder directly onto the end of the RA shaft. They are not cheap at about £800, but give very smooth tracking with no PE. This is the raw unguided mount in blue, with guiding in yellow, and guided with encoder in pink:

If I started this project all over again, my polar wedge would look totally different. The hinged plate model of Beacon Hill mounts might heve ben adequate for visual, but for high accuracy imaging it's pants. (My highest resolution imaging is 0.4 second per pixel on this scope). The lower part of the wedge is a commercial gate hinge welded to two steel plates, the fulcrum created by the adjusting rods at the top of the plates pushes the hinge apart at the bottom, any imbalance in the load when moving between East and West of the Meridian rocks the mount, hence the bracing plates. But it still sucks. If I were to start with a clean sheet, I reckon something like this as a polar axis would work: http://www.astronomyblogger.com/homemade-stuff/homemade-equatorial-mount/ but naturally, in 20mm ali, not 18mm ply😀 Naturally, with so much invested in the mount already, and with so few clear nights this far West, it's a law of diminishing returns, so I'm fettling what I have, not stating anew. I've spent a fortune in this last year on an encoder for the Polar axis, this is going to be my last big spend on this mount. Huw

Ahh, what's missing in that photo is a plate across the front, joining both side plates, just behind the box section. This solidified the mount enormously, maybe a further bracket from the worm block spacer box to that would make sense. Ta Huw

I'm moving the worm block and motor as one unit, the 'hinge' is quite some way back from the worm/wheel. Rigidity is paramount. My dec assembly is quite sturdy, not so sure about the R.A. I've had to build up a 'spacer' from 2"x4" box section to put the worm at the edge of the wheel, not ideal. Huw

Sorry Michele, my tech drawing skills are terrible, and I don't use any helpful drawing packages, just Photoshop, so here goes in 3d Does that make any more sense? The green is the 0.2mm strip of stainless, the blue is the part of the mount/worm block, and the brown/orange are the fixing strips. I find this works really well, having great stiffness to sideways and twisting forces, whilst allowing a relatively good hinge angle, since the max it has to open is the tooth depth of the worm. I first used flexors in a Clement focuser I built a few years ago: Huw

Sorry to hear you're not well, keep safe and warm, health comes before telescopes. Huw