symmetal

That's an impressive image Wim. Not sure if there's a hint of the debris streams visible. 🤔 I found this article detailing the globular clusters and evolution of NGC147. If this poor weather here clears I can have a try with my RASA 11 and LRGB filters to see if any more features can be seen. Alan

If you enable 16-bit mode in the guide camera driver setup you should achieve much higher SNR figures which may assist PHD2 in choosing a star. Also it's worth selecting multi-star guiding in the 'Brain' guiding tab as this will use many stars to derive the guiding corrections so having one of them saturated won't affect the result to any noticeable degree. Alan

Unfortunately the weather hasn't been kind the past few weeks and I've just had the odd hour or so with gaps in the clouds to check collimation and camera spacing. The collimation was off and it took a whole turn on one of the screws to get it right. Spacing seems a bit more critical compared to the RASA 8 and am at 56.0mm at the moment as the recommended 55mm gave elongated edge stars. The ASI 2600 is pretty good now but the ASI 6200 was still showing poor stars in one corner despite the tilt test jig being spot on. Waiting for the next clear night to continue. None of the RASA 8 asymmetric flaring though. 😊 The Moon's been out and the 2600MC sky background was swamping the read noise by a factor of 5 at 6 secs exposure. The 6200MM was doing it at 2 secs with a luminance filter. 😲 Waiting for a moonless night to get a more useful exposure value. I really need to get fast NB filters for the 6200 and the 2" Astronomik 6nm fast filters are £650 each. 😬 Astronomik are only 1mm thick so they all need to be the same manufacturer to maintain the spacing. As the RASA 11 is the same FL as the FLT98, the FLT98 looks a bit redundant at the moment. Alan

Thanks for posting Göran. Plenty of extra detail revealed compared to other images. It reveals that all the objects in view are actually part of a whole and not isolated features. 😃 Alan

Excellent Olly. Looking at images produced before star removal was available the sheer number of background stars tended to overwhelm the VdB nebulae and they struggled to make themselves seen. Alan

I'm afraid it's the same issue Göran though is being masked somewhat by the odd blue halos. If you contact Celestron they will fix it but it needs sending back to China for a replacement mirror and at the time, (a month ago), Celestron didn't know how long this process would take, as they've also returned all their RASA 8 stock to China because of this issue. Under guarantee they will hopefully just replace the scope with a new one, once the issue has been resolved and they have fresh stock but it's worth contacting your supplier to make them aware of this issue. In the meantime you can make an aperture mask of around 180mm diameter which will solve the asymmetrical flaring issue over the majority of the image though it then becomes an f2.2 scope rather than f2. Alan

Thanks for posting Göran. Lots of fine detail shown even in areas which don't have a designation. And plenty of colour too. 😊 Alan

Look down the scope with a torch and see on what surface the dew is forming. In my experience, dew or ice on the sensor itself tends to form from one edge and progress across the sensor. I would get these circular dew patterns forming on the rear of the field flattener with my FLT98 when used with the Atik One CCD camera with the in-built filter wheel. On cooling the camera below zero, the sensor cover and filters would be fine but the field flattener would start dewing up from the centre outwards. When this happened, removing the camera and warming the FF rear with a hair dryer until the dew was gone would then keep it clear for the rest of the night with the cooled camera re-attached. Tried a dew band around the FF, or putting desiccant sachets behind the FF when not being used, but neither of these had any effect. When I used newer cooled CMOS cameras though the problem never occurred. 🤔 Alan

ebay has them too here and with a dust cover too if you wish. 🙂 Alan

You'll likely find that most cables now on sale are all USB3 and will work if fully wired, but the thinner USB2 ones are preferable. I use these USB2 ones on my ASI120 Mini and they work fine. They are called charger cables but they do data transfer as well. Alan

There is no focus tube access from the rear like an SCT, and the rear is sealed as shown here. Focusing is only by moving the primary mirror. The camera mounts on to the front of the corrector plate as can be seen in the first couple of photos posted. 🙂 A quad lens assembly is mounted on the rear of the corrector plate to correct the light entering the camera. This lens asembly housing was what was collecting the bulk of the swarf. Alan

Thanks @ollypenrice. I have already replaced the front ring that clamps the corrector with the Celestron heated dew ring as per Celestron's instructions, having the scope pointing vertically on the mount, and you then reveal the grub screws around the edge pushing against the corrector plate to keep it in place. I wouldn't want to remove it at the moment, as it's still under guarantee, at least not without Flo's and Celestron's say so, but as you say it looks relatively easy to do. Alan

Lens assembly casing is clean again, but had no luck clearing the swarf on the bottom. I tried using long lengths of heatshrink tubing which reached down there but there was no way to manipulate it properly and by luck, picked up 1 piece in 30 mins of trying. I did move the magnet around on the outside of the tube and the swarf wasn't attracted to it so it's probably aluminium. If it was steel there likely wouldn't be so much of it. Here's the swarf left in the bottom of the tube. They are out of focus so the specks appears larger than they are. They should hopefully spend their lives rolling around the tube edge and work their way to the rear when the scope points vertically without settling on the mirror. It's a pity there aren't any access panels in the scope tube which would make life easier for dealing with issues like this. Alan

Thanks @Stuart1971, My first 3d printed tube worked a treat and removed all the swarf sitting on the lens assembly casing. However running the screws through again caused more swarf to fall. I then used the new 10 UNF 1" screws that arrived today and they have a much more positive feel to them when screwing them in which is good. While one went through nicely the other was stiffer and caused even more swarf to fall as it cleared out the thread again. This was the one where the original screw end was clearly worn where it had cut its own thread. Just printing a longer tube which hopefully will reach the bottom of the scope tube where some swarf accumulated too. Hopefully I'll reach a stage where the screws can be inserted and removed without more swarf tumbling out. Alan

Thanks Steve. Though I would say that dovetail bars are intended to be removed and refitted by the user, and I've had no issue doing this with any other scope. The RASA 8s I had before had the separate top bar fitted by me in each case, as they don't come with a top bar, and they came on and off easily without dropping swarf into the scope. The magnets have arrived though I may wait for some thin stiff tubing to arrive tomorrow as I think sucking the swarf out is the better option, if possible. I'm currently 3D printing some tubing which may do the job, so it's likely it won't need to be cleaned after all. Alan

Another option is a length of stiff tubing around 4mm OD, like ABS, brass etc, and attach it to a vacuum cleaner to suck the swarf out. I could even try 3D printing some square tubing which may work. 🙂 Alan

There is no real strength required in the lens assembly holder and to save weight, I'd hope they used aluminium for that. The smaller magnets of 3 x 0.5mm have a pull strength of 80g so shouldn't be too strong, compared to 270g for the 3 x 2mm magnets. I'll bend the wire back on itslf and solder it once threaded through the magnet so it shouldn't pop off. The tube must be aluminium as it isn't magnetic at all. I tested the outside areas with a magnet and found that stainless steel is only slightly magnetic compared to 'normal' steel. Zinc plated bolts and stainless steel bolts show this quite dramatically. The original black bolts used on the dovetail are only slightly magnetic so possibly stainless. Kays Fasteneners black coated screws are classed as high tensile steel which is generally stronger than stainless steel. Alan

Yes, I'll let FLO know about this thread tomorrow, (no pun intended) and see what they say. The threads on the plate appear OK as with the bolts cleaned up and no dovetail to limit the travel they screw in quite nicely with no further grinding, but there's no telling how much good thread is left. New bolts, hopefully arriving tomorrow should give a firmer grip, and if the 1 1/4" inch ones don't protrude into the light path, which I don't think they will should ensure that the full plate thread is at least being used. The CN topic I linked to in the last post does say to expect for swarf when removing the dovetail so this seems to be standard. Using UNF on the front pair of screws compared to UNC, like the rear doesn't seem a good choice as the volume of metal between the threads is reduced. There don't seem to be reports of RASA 11s falling off mounts though, so this seems to be just sufficient to hold the scope. 😬 Alan

It's possible, though the plate the dovetail screws screw into is fairly thin, around 3mm at most it looks like, so I was hoping it's steel. I've ordered some neodymium magnets anyway, 3 x 2mm and 3 x 0.5mm which arrive tomorrow so we'll find out. 😉 I'll try drilling a hole through one with a PCB drill hopefully without it shattering first. Drilling underwater avoids the magnet getting too hot and losing its magnetism as well. Fingers crossed. 😊 If they aren't magnetic, at least being metal shavings they should eventually end up rolling around the inside of the tube and not get onto the mirror or corrector plate as long as I don't tilt the scope while they are on the lens housing as they are at the moment. A fine modelling paint brush may reach them. Alan

Having had my new RASA 11 for three weeks now and still no weather to try it out I've been tidying up the attachments to the top dovetail bar and fixing a carrying handle to it. I was going to drill mounting holes in the bar so removed it, though I ended up using losmandy clamps to hold everything so didn't need to drill the dovetail bar. However, when unscrewing the front two dovetail mounting screws they it felt like they were grinding and they came undone after unscrewing only about 2 to 3 mm so very little of the screw is actually engaged with the scope body. 😲 It seems the bar front screws screw into a plate mounted below the scope front metal assembly piece and not into the front metal piece directly which just has drilled holes. The screws are only just long enough to reach the plate and it looks like the screws themselves were used to create the thread on the plate as the end few mm show significant wear. Here's a picture of the plate viewed from inside from a topic on CN detailing disassembly of the RASA 11 V2 Here are the screws from mine showing how much engages with the plate. I think the thread at the top of the plate is worn on one side as only about 2 turns actually feels it's engaging with the plate. The rear dovetail mounting screws are fine as the scope rear metal assembly is actually threaded rather than just being a hole so around 5 or 6 mm of thread engages with the dovetail screw which unscrews fine with no grinding. Another odd feature is the rear screws are 10-24 UNC 1" while the front screws are 10-32 UNF 1". The result is swarf falling inside the scope when the front screws were removed and replaced as shown here with most lying on the assembly holing the front lens assembly with some falling to the bottom of the scope. I'e ordered some replacement 10-32 UNF 1" screws from Kay's Fasteners on ebay as well as some 1 1/4" screws which should hopefully give a chance of a more reliable grip. I've been wondering how to possibly remove the swarf without removing the front corrector plate which will invalidate the guarantee and upset the collimation. I thought about trying some tiny neodymium magnets you can buy on Amazon for a few pounds. You can get some 1 x 2mm and others 3 x 3mm which will drop through the dovetail screw holes which are around 4.6mm in diameter. I don't want to have the scope sent away for cleaning as this is already the fourth RASA I've had. I'm assuming the mounting plate is made of steel and not aluminium. Being fairly thin I would hope it's steel. I can contact Celestron to see what they suggest. Perhaps the whole front black assembly, can be removed from the white tube via the mounting screws which avoids removing the corrector plate on its own. I don't think that removing a dovetail plate should be cause for invalidating a guarantee though, and they should be removeable without metal bits falling into the scope. 😬 Anybody think magnets on a bit of wire may help. Have to ensure the magnet doesn't fall off the wire, though if it did, it could be used as a loose swarf collector as it rolls around inside the scope. 😊 When the scope is on the mount and tilted on its side the whole weight of the scope is dependant on the engagement of a few mm of four relatively small screws, smaller than M5, while things attached to the dovetail bars use M6 or 1/4" screws. 🤔. The handle I fitted is attached with M6 screws which seems overkill in comparison. Alan

As has been mentioned the straps themselves have no polarity so it doesn't matter which wire goes where. The cable is likely 2 core red and black, so to maintain convention put the red to the RCA tip. The tip should carry the PWM switched 12V and the screen should be ground, (or negative) if the dew controller is designed properly. Some older dew straps used single core screened audio cable, rather than 2 core unscreened, in which case the single core inner wire goes to the RCA tip and the cable screen goes to the RCA screen. Alan

Pin 1 is the negative so black to pin 1 and red to pin 2 on the GX12. The manual page showing the pinouts is viewed from the outside looking towards the mount. it would be nice if they also showed pin numbers where appropriate though. Your cable sheath diameter is quite large and you may have difficulty getting it through the hole in the cover of the GX12 connector. As long as you can get the outer sheath under the cable clamp on the rear you should be fine, but even that may be a squeeze. You may have to end up using thinner cable. Alan

It depends on what capture software you're using so it'll be easiest if you say what you're using. 🙂 Alan

Yes, that seems to be a bigger problem. 😬 Hope the new one works OK. Alan

There will be a 'camera properties' or 'camera setup' option in whatever capture programme you use which will bring up the Ascom driver setup dialog, (if you're using the Ascom driver) similar to this You likely need to select 'Advanced' in order to display the Camera Setting section where the USB Limit can be set. It is usually default at 40% which is the safe lowest setting but this may have been changed without knowing by other means. For small to medium size sensors cameras I can usually set it to 100% (full speed) but with APS-C or larger I need to set it at 70 to 80% maximum to avoid error messages or the program hanging when downloading an image. As you last reported that using the camera USB ports it also fails on your main PC, it does suggest that the USB traffic is overloading the system, so hopefully the above will help. 🙂 Likely not related to your problem, but it's best to inhibit the host PC from turning off the power to USB ports to save power if it thinks they aren't being used. You can set this in Device Manager and expanding the 'Universal Serial Bus controllers' section. Right clicking on any entry ending in 'Hub' and selecting 'Properties' and then 'Power Management', untick the 'Allow the computer to turn off this device to save power' on each entry. Alan