MaartenM

Hi all, a bit of an update or rather another question. The pin referred to in the pictures and posts above actually moves in and out with the turning of the focus knob. That means it is effectively connected to the mirror, so it seems pretty sure it has been added to address mirror shift in some way. The thing is, as can be seen in the picture above, it is not a screw, it isn't threaded, there is no spring. It is just a little rod, maybe 5mm thick, attached to the mirror. Strange enough it doesn't stick out exactly perpendicular to the back of the scope but I can't figure out whether that is just sloppy drilling/fixing or whether it's intentional. If I focus, there is some mirror shift (not unheard of in these old sct's) and if I push the pin I can correct the shift somewhat. Does anyone have any idea how this may have worked or is intended to work? Thanks in advance! Maarten

Thanks all for the responses. It is indeed an old beast so the absence of coating indicators is no real surprise... Further inspection shows that immediately next to the focuser there is a small hole, covered with a little plastic cap, which I'm sure must be the hole that will take the bolt to secure the mirror for transport... The various bits and pieces of info on the web indicate that the hole is next to the focuser. So it would seem that the "pin" on mine is not in the transport locking hole but was put there on purpose - some other info I found suggests that the best place for the mirror lock replacement is on the OTA back plate opposite the focuser. It looks like this is a Meade 2120, heavily modified by a previous owner ("McGyver modified" as someone on another forum said). I guess the pin has something to do wih locking the mirror but the thing is stuck... maybe that's what it is meant to be... Meanwhile, mooching around based on the various comments, I did find out that the amount of play in the focusser (almost 3/4 of a turn) seems excessive... Focusing the thing for photographic purposes is indeed a chore so maybe I should look at that first... All further comments much appreciated! Best regards, Maarten

Hi all, I need some help to identify what model this telescope is. It is obviously a Meade 10" SCT but that is where my identification skills falter... I've been googling around and it is definitely an old beast, heavily modded by a previous owner. It would be nice though to know whether this is/was a 2080, an LX5, an LX50 or still something else. It was converted to GEM obviously, and also the finder scope is not original (it's an Orion (or the like) small 6x30 affair). The OTA is flocked as far as I can see and the whole OTA was, or more likely has been, spray painted matt black at some point in its life... Finally it has a pin of unknown functionality sticking out of its back next to the eyepiece hole. The pin is not moveable in any way by hand, it may be stuck or in fact fixed by design but I don't dare to take pliers or something to it to see whether it can be moved for fear of breaking something. To me, also after looking at Uncle Rod's used SCT guide, many Meade OTA's especially from the early years look quite alike. But no doubt there must be experts who can shed some light on what exactly this is. Many thanks in advance for any tips! Best regards, Maarten

Hi both, thanks for the feedback! Stuart, maybe indeed I am already in the ballpark of what I could expect. I ordered a 2-layer TEC from China and intend to see whether that will gain me some more cooling.... Is there an optimum temperature for a CCD or is it just the colder the better? Peter, I have seen a lot of reference to moisture so no doubt that is the next challenge.... What is this desiccant tube you speak of? Just storing the camera dry with silica or something attached while in use? Just FYI, the previous owner who installed a PID in the QHY8 had wired things so that he could set a temperature and the PID would just switch off cooling when that minimum temperature was reached... and switch on again when the temp reached an selectable maximum after that. I guess that could somewhat control any freezing at the cost of somewhat variable sensor temp when taking pictures. So I'm not sure that would be ideal. Also, the constant switching on and off of the TEC and the fan might be less than optimal for the durability of the system. Thanks again Maarten

Hi all, a bit of a progress report for those of you who took the time to respond to my questions. I opened up the camera only to find that someone had tried to "repair" it at some time. There was a TEC (peltier element) inside, and a bit of aluminium padding, and heaps of thermal paste to create a bridge from the TEC to the housing. The thermal paste had completely dried out and there was little or no thermal bridge left. The TEC was loose. So I cleaned the whole thing as well as I could and with new paste and a better-fitting 4mm piece of aluminium I am able to reach about -5 Celsius at an ambient of about 20. So decent progress... but not to the -20, -30 or lower temps that should be possible... So futher googling and foruming revealed that the original TEC is a 2-layer affair with a greater temperature gradient than a single-layer. The "repair man" I mentioned has placed a single-layer TEC with some aluminium in place of the original double-layer. So that may well account for the low-but-not-very-low temperature. I am now trying to obtain a compatible 2-layer TEC... the part nr of the original one was apparently TEC2-25504 and I cannot find any reference to that number (except for one pdf in chinese!). The only thing that can be deduced is that it is a 2-layer TEC rated at 4A. QHY is less than responsive to any of the tickets I lodged and their forum is closed for registrations (so I cannot pose questions), so I went ahead and ordered what I think is a close equivalent TEC... Delivery will probably take a week or 3 so I will report back! Meanwhile, if the skies clear up, I will try to see what the camera can deliver at a less-than-optimal-but-still-sub-0C temperature. Best regards, Maarten

Just to report some progress... I replaced the dc-dc converter IC in the DC101 and then the miniDIN outputs gave -18.5 and 19.5V ! I found that close enough to try the camera again and lo and behold, a very different picture in EZCAP - black when I put my hand in front of the camera, lighter when I do not, shadows falling on the sensor clearly visible on the screen - so, the sensor still has life in it! However, not all is as it should, I think.... I am still not sure cooling is working adequate. The outside of the camera gets to some 35 deg C, so say somewhat warm to the touch but not hot at all, with ambient 25C.... I am not sure that is warm enough to guarantee an ice-cold peltier inside? The temperature sensor inside indicates some 16C at its lowest.... either the cooling is broken or the PID sensor got detached inside? Attached is an image from the sensor with the cap on so in pitch black, and then stretched. The camera was on for some 15min at the time. The image was taken with APT, exposure 100 sec, using the ascom driver for the QHY8 and then autostretched. There are a number of issues I can see... - It seems quite noisy to me, I've seen QHY8 examples virtually noise free for these circumstances... - The darker bar on the right - something wrong with that side of the sensor? I don't think it was visible in EZCAP. Likewise the white and black lines at the top and the left, although that bothers me less. - Why is there a clear top to bottom gradient... remember this is with the sensor completely covered. - I only seem to get grayscale images... I thought the QHY8 was a OSC camera?? So still to resolve - and any suggestions much appreciated: - Is the camera cooling? - Is the sensor functioning ok? As an aside, I have EZCAP crashing on me all the time, and also in APT the ascom driver doesn't seem 100% stable. This could of course be a hardware thing, but it could also be that EZCAP and/or the QHY8 driver and/or the ASCOM QHY8 driver are not behaving well on my win10 64 i7 machine... Any pertinent advice, thoughts, experiences most welcome! Best regards, Maarten

Hi Peter, indeed that is a DC102, the conversion I have is using a DC101. For the voltages on the mini-DIN that should make no difference as I understand (maybe incorrectly) that the temperature control takes place via PWM of the 12v supply? With the DC101 version I have, the PID just switches off the 12V (and thus the fan and the peltier cooling) when a certain temperature is reached. This document seems to suggest that the min-DIN power (so not the 12v fan/peltier power) should be + and - 18v, which is the same as a side reference I found on an old discussion on the QHY forum... Thanks for your help! Maarten

Thanks Carole. I did try APT before (using the ASCOM driver for the QHY8) but no luck... Best regards, Maarten

Hi Stuart, thanks for the response. This was bought privately via the Dutch version of ebay... so no going back, I admittedly took a gamble (although I had good reasons to believe it would work). Having a camera this old repaired will probably cost more than a new one so if I can breathe some life into it I would much prefer that. If not I will have to accept the loss... As I see some pretty technical messages here now and then I thought to give it a try. Best regards, Maarten

Hi all, first post here and almost absolute noob... so be gentle... 😀 After getting started in astrophotography a couple of months back with a HEQ5pro, an ED80 and a nikon D750 I got an opportunity to buy an (old) bigger scope (LX50 10"), a bigger mount (EQ6pro) and an oldie astro camera, a HQY8. I think the camera (which hadn't been used by the previous owner, but extensively by the one before, some 5+ years ago) is broken... but I'm not sure. I dowloaded the most recent driver (2009....) from QHY, and the EZCAP software. Camera was detected but in "liveview", after fiddling with offset and gain, I generally get a gray-to-black left-to-right gradient, with some horizontal lines. Strangely, this doesn't change whether the sensor is covered or not. ONly when shining a torch directly on the sensor I see a small brightness difference. The previous owner made a modification to read and control the sensor temperature (adding a PID and an internal thermocouple). While the fan spins and the camera gets warm, the sensor temp does not go below maybe 10 degrees (C) from ambient.... The 12v power to the camera is via a DC101, switched on and off by the PID.based on the temp sensor reading. I measured the mini-DIN plug voltages from the DC101 and they don't seem right - about 13V and -1.7V.... So it looks like the DC101 is broken. Online there is virtually nothing to find on these ancient products. So, maybe someone on here can provide some insight: What are the correct voltages on the mini-DIN connector on a DC101? What is the miniDIN voltage range for a QHY08 - can it be powered by a (non-QHY) power supply of e.g + and - 12V? How can I be sure cooling is working or not? The PID added to the QHY8 seems to indicate cooling is not working below say 15 deg C, but the camera does get warm, not hot though... is the miniDIN power needed besides the main 12V to ensure cooling? Would it still be worthwhile to have the camera checked and hopefully fixed? Any other thoughts or ideas I could try? Sorry for so many questions in a first post but TIA for any help or tips! Maarten