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Dreek
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Spores on the primary mirror! After a long period of storage in the school (COVID of course) the primary has some spores of fungal growth on its surface. Any advice about cleaning this would be gratefully received please!
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OK, finally built the trolley / go kart for the Newt. Much safer than teetering along with a sack barrow!
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Today's job is to make a go-kart for the 'scope... For health & safety reasons (climbing/falling) we're having to detach and move the main tube indoors when the scope's not being used. I've tried this with a sack barrow, but it's too big and is on the verge of dropping. So it needs a go-kart (and by the way, the Met Office said it was going to be sunny today didn't they? Easy life...). Watch this space...
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Torque Measurements November 2017 Eventually I want to fit a RA drive to the telescope, but it's going to have to be bespoke. First step is to characterise the torque throughout the rotation, with the scope pointing forwards and reverse. It's a bit uneven, but that's probably a result of being 52 degrees inclined (and plain bearings).
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First night time stargazing test - Moon - 25th November 2017 Managed to get a test in November 2017, checked out the collimation, and viewed the Moon with eyepieces and camera. All good. Moon - Atik Infinity on Newtonian 25-11-2017.wmv
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Spent all day in the boiler/storage room at the school today, working on the scope. I now have the camera, the Baader focuser and a red dot finder, along with a beautiful re-coated primary. First I made a somewhat agricultural wooden frame to hold the scope during painting and fitting. Took about four hours. Then I made a template and started to enlarge the hole for the new Baader focuser (which is superbly engineered by the way). Lots of drilling! And finally I managed to get a coat of back paint on the frame. Pushing hard to get this project up and imaging in the new few weeks. Gin and tonic now I think...
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Great advice, thanks Neil. This looks like my calcs are about right - assuming my figures for the sensor are OK, which I think they are.
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Friends, could you help me with a sanity check of some calculations please? The big telescope's primary mirror is now resurfaced and I'll be getting it back by the end of September - the school are cranking up the excitement, and I'd like to be able to predict what sort of objects we'll be able to see. That's where I could do with my sums checking, before I make any rash promises. The imager will be an Atik Infinity camera, which uses the Sony ICX825 CCD sensor. I think this is 11mm diagonal and 1360px * 1024px (active), with 6.6um pixels. This will be in prime focus position (I hope). A new good-spec focuser is being fitted to help this. The approximate focal length of the telescope is 1560mm (including an estimate of path length through the secondary mirror bend). If I'm right, I reckon this will give me a pixel subtense of 4.225urads, or 0.8715 seconds of arc. So, for example, Lyra's Ring Nebula (0 deg 2' 30" diameter) will cover 172 pixels across (i.e. about an 8th of the camera picture width). Does that sound about right? Also, are there any pitfalls to look out for? For example, how do I know I'm going to fit the image exactly over the sensor? Thanks for any help you can give...
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Neil - and that's a realistic and significant scenario -the youthful cricket/rounders fielder staring skywards (ironically) and backing into the telescope. It's destined to have a cage built around it, with the main tube being removed and stored indoors. But that'll be part of a separate fund-raising exercise by the school - unless anyone here has anything they would like to donate...? Here's a shot of it taking shape on-site. Top-coat still needed.
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Update on the scope project - it's now at the school and having foundations set so it's stable flat and aligned. The primary is away being resurfaced, and I'm going for an Atik Infinity camera rather than eyepieces, so that children can do astronomy without individually teetering at the top of step ladders in the dark! New focusser and simple red dot spotter and we should be up and running. All this refurbishment has been funded by a generous grant given tom me by the William and Ellen Vinten Trust, who are responsible for helping many a young person on their path to engineering.
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Hi Jeremy, I found it in Suffolk, yes, but I believe it may have originated from the Norwich area, so Norfolk. No distinguishing marks on the primary at all unfortunately, so the mystery continues...
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Thank you for the advice; I'll give that a go. They are plain bearings, yes, but with bronze bushes.
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...btw, sorry it's been a long time since I was last here - I've had a bit of Carpal Tunnel surgery and it's not conducive to typing (or stripping gigantic telescopes)!!!
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John, Thanks very much for your support - it's coming along now, so hopefully the scope with rise phoenix-like into the night sky over the coming months. If I get stuck I'll shout out on this forum for some advice, but so far so good!
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Just luck really - a friend of ours shared an ambulance with a gentleman whose ill health had made him unable to use it any longer. Our friend suggested I might be able to do something with it, and the rest just fell into place. A few favours with trailers and mates from work and it was in my front garden!
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Update on the status of this project - now called "A Telescope for STEM in Bury St Edmunds". I managed to collimate the telescope to verify that it was still a viable instrument - it is - rough partially focussed iPhone shot of the moon attached. I've now fully dismantled the telescope and mount, taken the it down to the metal and reprimed it ready for its new matt black coat. Really looks like I mean business now - very pleased with the result so far. I'm delighted to say that I've also had some generous financial support from a local STEM engineering charity, The William and Ellen Vinten Trust, so I'll be getting the primary mirror resurfaced, new focuser, spotter and eyepieces. I'll also be designing a gearbox/motor to help position the mount - it's pretty heavy and the high stiction makes it tricky to fine-tune the aiming. The local school are currently fund-raising for building materials for the base and a structure to protect the scope so we're targeting first light and opening ceremony in September ready for the school year (and Autumn nights). Thanks for all the nice comments on the forum, I'll keep you posted!
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I have acquired an old 1960s Newtonian telescope which I am reconditioning as part of my STEM Ambassador volunteer work with a school in Bury St Edmunds. It's currently I my garden but when it's in a fit enough state it will move to the school grounds and hopefully be the seed of a new Astronomy Club in the area. I've already started doing after-school solar system and rocket making/launching sessions, so hopefully the scope will grow the club into something accessible to many children in the area. The reason for the post is I'd like to discover more about the provenance of the scope, so I wondered if any SGL members would be able to help? The primary mirror is 300mm diameter, the secondary elliptical mirror is 63mm (minor dia) by 90mm (major dia). Estimated focal length 1560mm, so f/5.2-ish. The tube is 1.6metres from the back of the primary box to the front of the tube; the front tube is 390mm diameter. It stands on a massive concrete block, angled at 52 degrees, which takes 4 men to lift... So far I have stripped it down, cleaned the bearings and regreased them so it is useable. I successfully collimated it with a Cheshire - first light showed not much coma, so happy with that for now. The focuser is rather tired and it needs at least a RA drive to make it easy to use, and the primary needs recoating. I believe it originally came from Norwich Uni, but I have no details. If anyone recognises this magnificent instrument or knows anything about it, please let me know - it'd be great to share this with the school as excitement mounts! Current state, in need of a lick of paint Original state (old photo)
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You're on it!!!
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