symmetal

Used a 400mm aluminium bar with 2 holes drilled for protruding M3 screws and it did the trick without having to heat it. Cleaning all the old threadlock out the threads with toothpicks is taking a while though.🙂 I marked an edge where the two parts met before unscrewing it so that assuming the replacement corrector is the same thickness I can apply the same torque as the original had, with fresh threadlock. The last thing you want is the central assembly to start rotating when you tighten or unscrew the camera. Alan

Actually the weight of the lens assembly hanging off the back of the corrector does balance the camera weight to some degree when horizontal but then doubles when the scope is pointing straight up so it must sag to some degree. Maybe not enough to cause a problem if it's thick enough, but then its own weight would add to the sagging effect. 🤔 Alan

That's a good idea. 🙂 Alan

@DaveS Thanks for clarifying that. I'd always assumed they were quite curvy. 🙂 Alan

Trying to separate the two components clamping the RASA 11 corrector plate but the lens removal tool isn't strong enough. It looks like threadlock has been applied at three spots on the thread. There is about 5mm deep of meshed thread. I've removed the lens tilt adapter which are what the screw holes/marks are on the lower picture. I can make a longer bar with two M3 screws poking through to give more leverage, and perhaps put the plate in the oven on low heat to possibly soften the threadlock. Googling suggests using WD40 to dissolve the lock compound. Anyone have any other suggestions? 🙂 Alan

Looking at the broken corrector plate of my RASA 11, I was surprised that it appears to just be a flat piece of glass. Laying a steel rule across it there is no visible curvature on either side and calipers measure 6.16mm thickness at all places from the outside to the centre. There are no shims to adjust its orientation to the mirror, as it just lies directly against a fixed metal flange on the scope front housing and is pushed against it by the front mounting ring screws. Four nylon tipped grub screws push against the plate edges from the side, to centre the front quad lens assembly which does the actual correction I imagine. I'd have thought there would be a ring of softer material betwen the glass and the metal though. No wonder the plate broke when the scope was dropped. There is some grey fibrous material each side of the plate where it touches the lens holder. The ring below the plate screws into the central ring and has two holes on the bottom to fit an adjustable lens assembly tool which arrived today from Amazon. 🙂 I may as well try fitting a new 'corrector' plate myself, when Celestron can supply one, as there are several Youtube videos on hyperstar corrector plate replacement and adjustment. It just looks like I need to get it central over the mirror as there are separate tilt adjustments on the lens assembly used for collimation. Here's the broken plate edge on, with the lens assembly removed. The lens assembly comes in from the bottom and engages with threads on the inside of the top ring on the picture. The push/pull tilt screws are just visible below the top ring. Alan

Excellent image Adam. You're right, at 100% it still looks good. Glad to see you left some noise, to stop it having a too 'processed' look. 😉 Alan

I actually have one that I bought for another purpose, not lifting engines. They don't travel well over grass though, and the scope is about 60 yds from the garage. The lifting height is possibly OK but one person manoeuvring it into position to engage with the saddle would be rather awkward. I bought an electric height adjustable table and fitted a plywood top, and 100mm castor wheels in place of the feet. 200mm castors would be better over rough terrain but they would require a separate mounting plate as they are too large for the existing base. 100mm castors just very neatly. A manual adjustable height would have been fine but electric ones seem very prolific. The scope will sit in a mounting frame fitted to the plywood top, with small fixed rubber castor wheels holding up the scope so it can easily be rotated into position for offering up to the saddle with the counterweight bar horizontal as shown in the video. If it's successful I'll post some pictures. 😉 Fixed castor wheels seems to be an oxymoron, but that's what they're called. 😀 Alan

A new RASA 8 will most likely have the mirror edge flare issue if you get one that's still in stock anywhere. I had to return three of them as they all had the issue, and got a RASA 11 instead. Celestron returned their stock of RASA 8 scopes to China for the mirrors to be replaced or re-worked. FLO have stated 90-120 days delivery which effectively means when ever they start shipping again. The RASA 11 is recommended if weight and cost isn't a problem, and you don't drop it like me. 😭 It doesn't have the limited backfocus issue of the RASA 8 so you can use mono cameras with a filter drawer, and gives very good stars out to the corners on full frame, although there is significant vignetting with the stock 48mm adapter. Back focus spacing is critical to get good stars, which can be misinterpreted as tilt, if it's out by more than 0.2mm. Alan

Thanks Wim. Most interesting. Looks like more non-stellar objects than stars. 🙂 Alan

Thanks Göran for another unusual image. Though it reminds me more of a pelican with a runny nose. 😊 Alan

I've used those USB 2 splitters and they work fine. In reality it's an unpowered 2 output hub so the USB2 500mA current supply capacity and data bandwidth will be shared between them. The EFW needs around 120mA so won't cause any problems and the bandwidth required is very small. 🙂 As an aside in another topic where you asked if the USB C output could be used to drive the filter wheel the answer is yes. You would need a USB C to USB 3 adapter similar to this and plug your filter wheel cable into it. USB 2 cables work in USB 3 sockets without issue. Alan

Some coarse focuser knobs have an extension that slides inside the focuser mechanism so the grubscrew shown next to the coarse knob may release it. The grubscrew may be a dummy one and once removed you can access the actual focus knob grubscrew below. There may be two of them 90 degrees apart so rotate the focus knob to check if you find it doesn't come off when you unscrew one of them. Alan

@George Sinanis Göran is imaging at f2 so 5min at f2 is the same as about 40min at your f6. So you would need around 80 hours total integration time to match it. Hope Göran doesn't mind me butting it but I'm at a bit of a loose end at the moment as my RASA's broken. 😟 Alan

FLO have had a response from Celestron, and Celestron have asked me to send it to Orion Optics for repair and quotes, and Celestron will supply them the parts as necessary. I'll email OO over the weekend with the details and see what they reply. It looks like major Celestron repairs may need to go back to China, and they've suggested this for a quicker result. Alan

Accidental damage is usually included in home insurance policies, unless you specifically opt out, up to around £5000 or so per item I believe. More valuable items would need to be specified individually on the policy. I'll need to check mine fully and report back. Yes, that's a possibility, with maybe blocks put around the outside to hold the OTA more securely in position. Care would be needed to avoid squashing the cables going over the rim. I have four cables , camera power, camera output, dew heater ring power and dew heater ring temperature sensor. 🙂 Alan

My 3D printed dew shield would support the weight of the scope as the rear slots into the dovetail bars but the whole thing would be a bit top heavy. A shorter one just long enough to clear the camera and a bit beefier could be used. 🤔 The rear is a possibility if the support is shaped to avoid (or incorporate) the rear handle, and avoid the autofocus assembly sticking out in place of the focus knob. Alan

Yes, the last part of the video where the scope lay on its side on the chair is the better orientation for a RASA to keep the camera attached. Your saw horse arrangement sounds good. I thought of mounting it on a low level trolley like this which would be handy for fine manoeuvering, and I have one in the garage. A raised frame could be fitted around the outside at the corners fixed to the bottom if necessary to stop the horse from sliding off and still allow the trolley handle to fold down when not in use. I can always lay another row of paving slabs if it would help. For use with one specific scope and mount, the height can be fixed so a height adjustment mechanism won't be needed. As you say an opportunity for someone to make them for sale. 😀 Haven't heard anything back from Celestron via FLO at the moment so it may be the New Year before anything happens in getting it repaired. 😐 Alan

That's a good video Stu. The second part where he had the scope in the horizontal position on the chair would be more applicable for the RASA to avoid having to remove the camera each time. I just need to find or make a stool of the correct height. Got plenty of time to do that now until I get the scope back. 😉 I was thinking of getting some thick foam mats to put around the base to catch falling scopes but the method in the video is much better. Thanks Göran. I was also thinking about how to arrange a pulley system to lift it which would mean having a temporary frame over the pillar which is a lot of hassle but your arrangement made me think I could put a couple of wooden uprights and cross beam in the roll-off plastic shed you can see to the right in the blurry last photo I posted, above where the scope sits when it's in the shed. A channeled cutout in the base ensures the scope always ends up in the same location. Then have a pulley system similar to yours attached to the cross beam. The rope can attach to the handle I fitted to the top dovetail bar. That's two good methods. The stool system shown in Stu's video is quicker to make so I'll likely try that method first. 😀 @Paul M One of these two methods may be suitable for you too. 🙂 Alan

Thanks @ollypenrice and @JeremyS I was a bit trepidatious when I first received it about lifting it on to the mount as there's only me here, but found a technique that seemed to work OK. The main issue is as you're lifting it from underneath to keep it upright all the time and not to let it tip to one side, as it quickly gets out of control. When the locking bolt seemed to tighten early I should have slackened it off and jiggled the scope around, instead of trying to see what was wrong. I have fitted a handle to the top dovetail bar which is fine for carrying it around but is too high to use when putting it on the mount. I could try finding a position to place a mirror so I can see the far dovetail groove while manoeuvering it into position. Alan

Yes, it should be covered by insurance, whether it comes under items in outbuildings, as it technically wasn't at the time of the accident, or personal items I'll have to check. I'll see what Celestron quote for repair first, as it'll no doubt impact the next premium. 😬 Alan

Thanks everyone for your replies. Much appreciated. I've contacted FLO and they are contacting Celestron UK and helping to arrange shipment and repair costs. Waiting for their response. Hopefully they can get and fit a new corrector plate and align it without it needing to be shipped back to China. I have an ADM losmandy clamp fitted to the lower dovetail bar which hooks over the top of the saddle to help take the weight while getting it into position though it's still back heavy without the dew shield attached so upward force is needed on the rear handle all the time until it's locked in. I think the right side dovetail edge clamped on the edge of the saddle at one point as the locking bolt didn't travel as far as normal. I should have loosened it off and jiggled a bit more but bent down to have a look while still applying upward force on the rear handle. The dovetail right edge likely dropped into the correct position at that point and the rolling motion to the right it created was too much to stop with the one hand on the rear. It continued rolling to the right and I had to let go when it had tolled 90 degrees or I might have broken my wrist. If I'd kept hold of it it would have likely swung down and landed camera first which would have broken the camera, corrector plate and possibly the front lens assembly. As it is, the top dovetail bar spread the force of the guide camera hitting the ground and corrector plate end got the most of the shock. I did find some scuff marks on the rear black casting where it rolled on to its side before coming to rest though they don't look too deep so I don't think there is any mirror damage. I could have left the scope on the mount in the shed all the time which in hindsight would have been better, but with November being very wet I would bring it in if the forecast looked bad for the next few days to save it sitting there in very high humidity all the time. I've lifted it on and off without incident around 20 times already so didn't think this would be any different. 😪 FLO were due to ship my Astronomik fast 6nm NB filters today, and they have kindly quickly added the ADM losmandy/vixen adapter to the shipment so I can at least put the FLT98 on the EQ8 while the RASA is away. Alan

I'm going to be waiting quite a while now due to my RASA 11 Disaster 😭 Alan

Took the scope out to put on the EQ8 for two clear nights imaging in a row, first for a long time. Lifted it onto the dovetail, tightened the middle screw until it was tight and while still holding the rear handle, moved around the other side to check it was in the dovetail groove on the other side before doing it up fully. Half way round it slipped and rolled off landing upside down on the concrete before rolling over on the grass. I found you can't hold back 22kg with one hand. 😖 In the freezing temperatures the dovetail bolt may have stuck while doing it up and the other side apparantly wasn't in the groove. The guide scope took the full impact and the 5mm thick adapter plate fixing it to the top rail bent significantly. The RASA looked OK until I went round the front. 😭 There are no dents or even paint scuff marks on the RASA casing or dovetail rails. The cameras and PC assembly attached to the top of the scope are fine too. It just looks like the corrector plate couldn't take the momentum of the central lens and camera assembly when the guide scope scopped the scope moving forward. The main mirror and central lens assembly look fine too as far as I can tell. The guide scope itself looks good apart from the dented dewshield. Objective looks OK. I won't be able to try for Göran's Blue Dragon now which was the target for 5 hours of moonless night tomorrow. 😟. I thought I'd at least put the FLT98 on the EQ8 and get some imaging done but that has a Vixen dovetail while the EQ8 is Losmandy. I've put an order in to FLO for a Vixen/Losmandy adapter plate to use the FLT98 on the EQ8 until the RASA comes back from being fixed by Celestron, but that can't be here until Friday so the two nights are lost. I could put the FLT98 on the AZ-EQ6 on a tripod tomorrow if I get the urge but I'm rather flat at the moment. Alan

I'll also have to try this with the NBZ and ASI 2600MC and RASA 11. I'm still waiting for my fast NB filters to arrive so I can let the 6200 loose on it. 😀 I've managed to get the flats sorted out now pretty much, with the Aurora panel, ND filters and longish exposures. Alan