kbrown

I made a wire harness using this technique:

How about folding your old cable and putting it in a flexible sleeve?

Back in the days when I used my DSLR (Canon 6D) for AP, PI was rather slow to process the CR2 files. Things were a bit smoother when I first converted everything to fits or xisf format. By default you'll get those anyway as soon as you start outputting new files. How much RAM do you have? I notice that was a big bottle neck with my old laptop...

I have to look into the paracorr in detail. Might work albeit expensive solution.

OAG did cross my mind but I don't think that's an option for me as there's no space for it in my rig (I think). I have a coma corrector in front of a filter wheel and the camera on the other side. I use barely any spacers to get to my desired back focus. The thinnest OAG I've found so far is 9mm. I have to double check but I think that's too much already.

So far I've been using a 50mm (180mm F/L) finder scope with a QHY5L-II as my guider setup. This gives me about 4.3" per pixel resolution. I've recently been using a ZWO ASI 183MC Pro as my imaging camera on my Sky-Watcher 250PX which gives me about 0.46"/px resolution with the 0.9x Coma Corrector in the train. My question is: Is my guider good enough any more? I've been toying around with the idea of using my 72mm (500mm F/L) refractor as the guider scope which would give me 1.55"/px resolution but I'd be adding more weight on the system which is already at or near the limit of my NEQ6 Pro. So far I've been using lin_guider as my guider software but will be trying out PHD2 soon as I just got it working with my QHY on my RPi3 which is controlling all the devices on my rig.

Wow, what a difference. Just used my scope for the first time after collimating it with this plus a laser collimator. Once I got both agreeing with each other I called it job done. Now I'm getting nice round stars. I'm slightly oversampling (0.40"/px) so I guess my remaining issues are down to good seeing, balance and guiding performance. Still need to properly analyse my flats and investigate if I have unwanted tilt(s) in my imaging train. Anyway, I've been having collimation problems ever since I took my scope apart for flocking and other improvements. The chesire eyepiece helped a lot to get the secondary mirror in the right place and orientation. Really happy how things have improved. Happy to share the STL if anyone wants to print one of these?

I have an RPi running an indiserver which in turn speaks to all my devices in my rig. The RPi is configured as a WiFi hotspot so I can drive the system remotely on my laptop with Kstars/Ekos. Couple of the devices (focuser and filterwheel) are home brew (Arduino based) for which I wrote my own indi drivers.

According to https://starizona.com/tutorial/eyepiece-projection-calculator/ the camera distance from the eyepiece isn't that critical and is actually a way to control the final magnification. I guess what I have should work. It's essentially two 2" nose pieces connected with an extension tube. The adapter is on the front nose piece and the camera on the back of the other one. I can slide the camera in and out within a limit. All I need is some clear skies to test this 😊

Probably done million times before but I thought I'd model and 3D print a cheshire eyepiece for myself. I printed it in three sections: The cap with the peep hole can be pulled out and since it's 1.25" I could pop in my QHY5L-II with a small CCTV lens to inspect the scope on my laptop screen. The reticle at the other end of the tube is also removable. I printed it with a 0.25mm nozzle to make it less obstructive. Seems to work fairly well.

I wanted to have the possibility of imaging using eyepiece projection so I thought I'd try to put something together with what I already have and 3D print the rest. I have no prior experience on the subject so any advice is welcome. I don't think I'll be doing any serious imaging this way but I thought it might be handy way to inspect the optics in a star test using a high magnification eyepiece for example. The thing I do not know is how far behind the eyepiece should the sensor go? Often the eye relief of an EP is mere few millimetres but does the sensor need to be at this distance? Here's what I've done so far: At the bottom there's my 3D printed adaptor where I can pop my eyepiece in. The adaptor screws into the M48 filter threads of a 2" nose piece as shown below: I have a way to attach my QHY5L-II mono to this system already but I'm unsure how far or close to the eyepiece it should be? With the system I have I can't get it very close at the moment...

Can't tell for sure from the photos but is that shaft permanently fixed on the orange collar or does it slide in and out like the stock shaft?

Thanks Mark. That is very kind of you! I'm in SE london so not crazy far away. First I have to decide what I want to actually do about this. My long term plan is to get a lathe as well but that'll have to wait until after we've reinstated a garage in our garden first but that's a whole other topic Clear skies.

I'd have to get the 10kg version which is 232 euros and might even have to add an extra weight on top as I'm not sure if the shaft is long enough. At the moment I use an extension to the stock shaft and two 5kg weights sometimes almost at the end of it. I know I'm pushing it but it's been okay as long as the whole shaft assebly doesn't wobble and jolt as it sometimes does in certain DEC angles. Maybe I could get the cheaper 5kg version and drill the centre holes of my existing 5kg weights so I can add them on the upgraded shaft too... Hmm...

Last weekend I was at the European Astrofest and saw this AZ EQ6 Pro mount. Does anyone know if the second saddle on the counterweight shaft is something you can buy as an upgrade or if this is a DIY mod? I have and old NEQ6 Pro mount so it probably would not fit directly but ideally I'd like to have something like this. Also at the same time I'd like to upgrade the shaft locking mechanism which isn't stable and causes wobble/shift when the DEC axis rotates. I'm aware of this but it seems a little pricey for what it is: https://www.teleskop-express.de/shop/product_info.php/language/en/info/p3025_Counter-weight-bar-for-EQ6--chrome-plated--with-5-kgs-counter-weight.html Has anyone gone the DIY way on the subject?

Last night I started having a closer look at my imaging train. I have a Skywatcher coma corrector attached to an Opticstar filter wheel. The CC requires 55mm back focus but this presents a bit of a dilemma. I have 1mm and 2mm thick filters which will lengthen the back focus distance by roughly 0.5mm and 1mm respectively so I'm not sure at what distance I should place my CCDs. At the moment I have it at 55.75mm hoping that would cover all combinations. Any insights on this? Haven't been able to test my rig yet.

Well I'm glad I asked. Thanks for the responses! Definitely gives me some ideas to think about. I'm not too concerned about the possible vibrations caused by walking in the obsy as most likely I'll be controlling everything remotely from inside the house. I'll probably isolate and lift the obsy floor using decking risers which should help a little but mainly for keeping everything a bit drier as well.

Hi, We've recently moved into a house with a back garden where I'd eventually like to build a RoR obsy at some point. There is an existing concrete slab at the location where I'm thinking to put it in. It's what's left of a garage that used to be there ages ago. I know it's not and ideal foundation as the concrete absorbs heat during the day and releases it at night causing heat turbulence. I'm thinking of decking the slab with deck risers to alleviate this but the bigger question is how to erect a pier on the slab? Has anyone done anything like this? Would be shame not to utilise the existing foundation for the building itself. Been thinking maybe bolting down a large brake disc on it with some steel rods poking up from it and then cast a concrete pier over and on top of it. Does this sound feasible? Not sure if I want to use a commercial steel pier bolted onto it as they all seem quite pricey for what they are.

I repeated what I said in my first post a few times and the results improved a bit every time. Last night I did a star test with only a 6mm eye piece in the focuser. I must have done something right as it seemed bang on. Well defined airy disk with the rings symmetrically collapsing to a point when approaching focus from either side.

Hi, I've just started to systematically go through and fine tune the entire optical train of my 10" reflector (Old Skywatcher 250PX with steel tube). The reason being because I have taken the scope apart pretty much completely in order to re-coat the primary, flock the tube, change the focuser to a better one plus add a DIY dew heater to the secondary mirror. After getting the OTA sorted out I want to eventually check the collimation of the imaging train too which consists of a Coma Corrector, Filter Wheel, Filters of various thickness and two different CCDs (Atik 383L+ and ZWO ASI183MC Pro). But that's another beast to tame... Ever since I've put the OTA back together again I haven't been able to achieve perfect focus. Initially the biggest problem was slightly triangular shaped stars which was due to the primary being held in the cell a bit too tight. I've now loosened it to a point where it's barely touching the mirror clips. I was still getting very slightly triangular (at least not round or perfect oval) stars so I thought a more thorough inspection is in order. I'm by all means not an expert so I was hoping to get some tips and comments on how to improve things. Starting with the OTA, here's what I've done so far: In order to position the secondary mirror in the centre of the tube (on the main optical axis), I printed out and laminated a template that allowed me to check and adjust the spider vanes visually. It's not the most accurate thing in the world but the best I could come up with. The template fits snugly on the inside of the tube and has a hole in the middle so you can easily see when the depth adjustment screw is centred. I then took my guider camera (QHY5L-II) and put that in the focuser together with a small CCTV lens so I could easily see what's going on inside the scope. Using the live video feed in SharpCap with the circular reticle turned on I adjusted the depth (towards/away primary), position and rotation of the secondary as good as I visually could. It seems like the secondary should be slightly closer towards the primary but I could not do that as my tilt adjustment screws (not original) are not long enough. It's not a massive error but I will fix it once I receive replacement screws. I then swapped the camera to a laser collimator and adjusted the tilt of the secondary until the red dot was in the centre of the primary. Then it was time to adjust the primary until the beam was reflected back to the centre of the collimator. After the above procedure I popped the camera back into the focuser to see what's going on and here's what I see: https://www.dropbox.com/s/cn3cyu4xcr2qtkb/Capture_00001.png?dl=0 https://www.dropbox.com/s/g8ky8j8kc0ujbr8/Capture_00003.png?dl=0 I was surprised to see the reflection of the primary being offset from the centre of the secondary. I have read about some fast Newtonians having an offset collimation by design but I do not know whether mine does or not (it is F/4.7). How can I find out? Any other comments on my methods so far are also welcome. I'm now thinking of taking the scope out and do some visual star testing without the imaging train in the focuser to see where I'm at. Again I'm not an expert in star testing so any tips on what to do and what to look out for are welcome as well. Cheers, Kari

I can't remember the slicer settings off top of my head for the infill and perimeter. I'll see if I can still find the files on my laptop when I get home. For the thread insert I bought V-Coil 04005 Thread Repair Kit (M3) and used it as instructed. Cheers, Kari

Here are the correct files... SA_CounterWeightShoe.zip

Due to someone requesting the STL files, I decided to attach them here. Happy printing. For maximum strength I recommend to print in this orientation and then superglue the parts together. Edit: Oops... Looks like I uploaded an old version of the model so I deleted it. Will upload the correct one as soon as possible. Sorry!

Thanks guys! The power bank is this one: https://www.amazon.com/MoKo-Multi-function-Emergency-Cigarette-Flashlight/dp/B01J0RXAV4 It has received mixed reviews but mine has been okay so far. I've only ran a single dew heater of it so far though. Had no trouble keeping it on for 5 hours straight in sub-zero temperatures. I think it had about 60% left when I re-charged it. Remains to be seen what happens when I put my cooled CCD, filterwheel and focuser behind it. Might have to get another one as a backup and come up with some kind of a hot swap system...

Long time no updates. This project is still alive though. Finally getting somewhere with it. I now have a way to attach the battery, raspberry pi, usb hub and a gps module to the tray without having to modify them. All that is left to do is the power distribution and wiring really. Topside. Just the USB hub here at the moment. Underside. Battery, Raspberry Pi and GPS module. Here's how it sits on the tripod.