dannybgoode

I am almost certain now it is a driver issue. I have completely flashed and re-installed Astroberry and even tried a different Pi4 and still the same. Bizarrely if I plug the camera straight into the Pi4 the result is even worse as per the image below. This is just the Pi4 and camera with a really simply EKOS profile for just the camera. If I plug it back into the PPBA and take a sub through that then it reverts back to the lesser artefact but still unacceptable for imaging. I have posted on the Indilib forum now as well to see if anyone has any ideas. My Altair Astro 130M works fine as does my Sony RX10M4 so it does seem to be specifically related to how the SX674 is interacting with KSTARS/EKOS. Ah well, gives me an excuse to try NINA out more fully

Thing is it has been working absolutely fine for over a year so I do not think it is a USB issue as such. I have tried it plugged into the Pi directly and the PPBA (which now has 2 dedicated USB2 sockets and 2 USB2/3 sockets) and have tried it in every port combination possible. It also works just fine on my laptop into USB3 and my PC via USB2 and 3. USB2 has been used for many many years to transfer far larger files than just a 5mb image file every few minutes. All my cameras use USB2 - even my Sony RX10M4 uses USB2 and generates far larger image files and does not have an issue at all running on any port I plug it into. Never had an issue before hence I suspect a corrupt driver or dying SD card more likely at the moment.

It was working fine before and USB2 can still easily handle the 5mb image files from my camera. 480mbits/s is more than enough for most applications. Plus it works fine over USB2 with my PC at the moment also. Don't forget USB3 is still pretty new and only the most recent cameras have it and there have not been significant issues with the many thousands of USB2 cameras out there. I am using it via the PPBA but have tried connecting it directly to the Pi44 also. Indeed earlier this year I only used it directly with the Pi and as I say it worked fine then. I suspect a corrupt driver or SD card more than a USB issue at this stage however I am keeping all options open at this stage.

Thanks Stuart - it is something to consider. It was working however so will check if there has been a driver update. Interestingly it works fine if I bin the image 2x also. Will keep investigating...

Slowly working through various combinations and no amount of swapping and changing ports on the PPBA or Pi4, unplugging various bits of kit to remove possible sources of interference etc have made any difference. I have since set the PPBA up with NINA and the camera works just fine in that configuration so we are left with something to do with either the Pi4, its SD card or Astroberry I think. I had to rule out the PPBA as the camera was working fine with Astroberry earlier in the year and the PPBA is the only thing that has changed however that does not seem to be the cause. Got a few permutations to run through to try and get to the bottom of it. The good news at least is it is not a sensor issue which was my original fear when I first saw the artefact.

Thanks guys. Terry at SX has confirmed it looks to be some kind of data transfer/USB issue (superb service as always from him). Everything is powered via and hooked to to the USB hub on a PowerBox Advance so there shouldn't be any issues with low voltage/current however I will run through a few alternate configurations to see if I can solve it.

No idea one this one. I've been getting my rig ready for imaging again and have been testing everything out and run some bias frames and noticed a strange artefact about 2/3's of the way down the each sub frame. It looks like a group of hot pixels and then a faint line running out from them across the whole sensor. Sensor was cooled to -20 and I've never seen this before. I've tried different exposures all the way from 1/1000s to 300s and the line is always there. Now, trying to rule things out I decided to install NINA not thinking it would make a difference. Err... I was wrong! No artefact at all. Follows are two 3 images - the first is a 5s sub from Astroberry, the second a 5s sub from NINA and the third a stack of 250 1/1000s subs from Astroberry stacked so you can more clearly see the artefact. Has anyone got any idea whatsoever what could be causing Astroberry to do this. Note the camera is an SX-674 running it on a Pi4 with a SanDisk Extreme SD card.

Couldn't agree more. In both AP and terrestrial photography people obsess about noise way to much. Sure, sometimes it can detract from a picture but so often people kill detail for a 'perfect' noise free image which is anything but perfect because of it!

I always wanted a telescope but never got one when I was younger. A few years ago though I bought a second hand SW 150P newt (the 750mm one) and a second hand AZ4 mount and was blown away with what that showed me. I still have it and will never part with it. That said even pre-telescope ownership, seeing Jupiter + three or four tiny moons through a pair of 10/50's is a moment which will stay with me forever also.

Well the good news is, it all seems to be working and certainly sounds very smooth. Certainly a shade quieter than it was before also so hopefully the effort will have been worth it. Can't wait to try it out now and see what the guiding looks like etc

My mount is so lightly used it didn't seem worth changing any of the bearings at this point but it is nice to have cleaned all the old grease out, free everything up, loosen that damned locking nut etc! And apart from that little hurdle the whole process is very simple, much easier than I thought it would be and next time I do it I may replace the bearings also. Will be interesting to see if it does run better now...

I am a big fan of Pegasus kit. Will be interesting to see the price on this one...

All done . Need to get my tripod in so I can test it all indoors, get the backlash tuned etc and make sure it is all working in time for 2025 when there might be a cloud free night...

@Jonny_H - the small bearing is a 60mm outer/41mm inner and 4mm thick, The large one is 90mm outer, 66mm inner and 4mm thick :). The holes in the locknut are 4.5mm - a 4mm pin fits them nicely.

Woohoo - RA locking nut finally undone. One of these did the trick together with a good wallop with a Clarkson :). The clutch plate was welded onto the RA mechanism though and has been slightly damaged removing it. I think it will still be fine for now but does anyone know where to get a replacement? I will not be tightening up the RA locknut nearly as much this time round so dismantling in the future will be much more simple Laser LAS5281 Tools Adjustable Pin Wrench : Amazon.co.uk: DIY & Tools

Trouble is the nut is still very much part of the mount water would possibly get to the control board etc. I am going to try some WD40 and plug up any holes with kitchen paper as a first point of call see if that helps

To be honest I shouldn’t have bought it as it was way way beyond budget however likewise, it was the whole history of the scope; the engineering, the fact it is a an early Thomas Back one, and yes of course the optics also. Oh and it’s true, Kruppax tubes just don’t dew. No idea why but it doesn’t matter what the temperature is - the objective simply refuses to few up I just had to have it

I’ve just had a quick look and there are a number of such tools. It’s just whether it is long enough and with a grip that you can get enough torque in to undo it. It does look highly promising though so if my McGuyver effort doesn’t work I’ll give one a go :)

Now isn’t that just the puppy! I’ve just bought a 3’ steel bar and some M4 bolts to make a suitable tool with however I will bite the bullet and get one of those if this fails to work

It can do and on a doublet it’s not such a difficult procedure. Triplets though can be hugely complex and time consuming and are often best left un-touched. If there were a known issue I’m sure you could pay for someone to try and sort it though…

I am sure the guys would be happy to check the collimation and adjust if necessary. Drop them a message and see if there is any benefit to having it on the Zygo as well. I wanted the report as all LZOS cells came with one but as I got my scope second hand the original certificate was missing so I was interested to see how it measured. Of course as they took the cell out to test mine it had to be re-collimated when they put it back in anyway

There are two separate processes. The Zygo test simply measures the optical performance of the objective and the objective cell does not need to be collimated to do this. If the objective measures poorly then there the options to correct it are pretty limited. You could dismantle the cell altogether and try and play around with the alignment of the individual elements but a) that could make things worse and b) is outside of the scope of this particular service. Once the guys know the optimal measurements they can then collimate the cell as a whole to try and ensure best performance at the eyepiece however it is easily possible to collimate without a Zygo report if you have the right kit. So the Zygo is more a diagnostic tool. If you know the objective is poor then you know that fiddling around with collimation will only get you so far.

Grrr - the tool I found is not quite the right size. I measured 50mm centre to centre of the holes whereas the tool is 50mm edge to edge so a shade small. I have tried making a tool by screwing some bolts through a piece of wood but the damned thing will still not budge. Not sure what to do now!! I could try making another tool with a longer handle for more leverage or maybe get some penetrating fluid on the nut in case it is seized or give up on the RA for now and just re-grease and re-assemble the DEC but that would be half a job.

The lens cell does not need to be collimated to produce best results, they adjust the laser until it gives the highest possible reading. A fuller description of the process is here: Zygo Interferometer - Rother Valley Optics Ltd

I’m not a Mac person however these M1 chips are seriously tempting me! My workstation has serious grunt but also eats electricity and whilst I’d need it for gaming I quite like the thought of a Mini for image processing and the like. Much more efficient that a hulking great PC…