The place to be when you have TEA. Discuss all kinds of test equipment.
Important: Use tags for the type of equipment your topic is about.
Forum rules
Use tags for the type of equipment your topic is about. Include the "repairs" tag, too, when appropriate. If a new tag is needed, request one in the TEAdministration forum.
BU508A wrote: ↑Tue Jun 24, 2025 8:57 am
Remove starlink trails:
I'd say, take some pictures shortly after, combine them and remove the starlink patterns.
Perhaps a similar approach would work for finding interesting objects.
tggzzz wrote: ↑Tue Jun 24, 2025 8:12 am
I'm having difficulty understanding how you can find/select the interesting objects to examine. So many pixels, and interesting objects are often only a few pixels in size.
If you take the guided tour, you eventually end up with RGB pictures of meteor trails
The colorful streaks in this image are asteroids — the streaks record their movement across the sky from left to right. This image is a combination of multiple observations taken with four different filters. The asteroid moves between each observation, and each filter is assigned a different color in the composite image, resulting in the asteroids' multicolored paths.
Typically, in a deep image like this one, scientists carefully remove moving objects so they don’t impede the study of static objects. We chose to leave them in this image so you can see Rubin’s dynamic view of the sky!
"Time on telescope" is a scarce resource, so I imagine people will be reluctant to take the same picture multiple times. But what do I know.
Since it's a publicity splash for a brand new prestige telescope, and they definitely wouldn't want to show a picture with a satellite track across it, or any other sort of blemish, I venture that the scarcity of "Time on telescope" wouldn't enter their heads.
"Time on telescope" is a scarce resource, so I imagine people will be reluctant to take the same picture multiple times. But what do I know.
Since it's a publicity splash for a brand new prestige telescope, and they definitely wouldn't want to show a picture with a satellite track across it, or any other sort of blemish, I venture that the scarcity of "Time on telescope" wouldn't enter their heads.
For a publicity splash, I agree.
For Real Work (TM), there will be satellite tracks, and scope time is fought over by researchers and institutions.
For amusement, here it is with asteroids and after asteroids are removed. I suppose the fact that they can remove asteriods indicates they can remove satellite tracks, but the satellite tracks will be much larger and brighter.
Screenshot_2025-06-24_19-08-17.jpg
Screenshot_2025-06-24_19-09-39.jpg
You do not have the required permissions to view the files attached to this post.
Satellites are well tracked as is space junk. Commercial airliners also usually fly on predictable paths. Military aircraft are a different, but much rarer problem. It can't be all that difficult to manage time on the telescope to accommodate these things. Anyway, large numbers of satellites have been around for at least 30 years. It must be a problem that operators of large telescopes have learned to live with. I don't believe that at first light, the leaders of the Vera C Rubin Telescope project said, "Oh shit!. It works pretty well, but the images are messed up with satellite tracks, meteor trails and passing UFOs. We didn't think about that".
Zenith wrote: ↑Tue Jun 24, 2025 8:09 pm
Satellites are well tracked as is space junk. Commercial airliners also usually fly on predictable paths. Military aircraft are a different, but much rarer problem. It can't be all that difficult to manage time on the telescope to accommodate these things. Anyway, large numbers of satellites have been around for at least 30 years. It must be a problem that operators of large telescopes have learned to live with. I don't believe that at first light, the leaders of the Vera C Rubin Telescope project said, "Oh shit!. It works pretty well, but the images are messed up with satellite tracks, meteor trails and passing UFOs. We didn't think about that".
Well...yes.
OTOH the astronomers have been complaining about Starlink. What I don't know is the extent to which they do/don't have a problem.
They did move to a pretty inhospitable place (Cerro Pachón in Chile) to avoid atmosphere, humidity, and lights. They are still missing atmosphere, but now there are lots of sometimes very bright lights in the sky.
Displays in vintage equipment can be an enormous problem. Very often they are specialised VFDs or LCDs and the original is expensive or unobtainable. The design can be quite elaborate. Sometimes analogue meters can also be very hard to replace.
There's a huge market for small modern computer displays for mobile devices and they are available in a large number of form factors, including round ones. They can have a very high resolution. For instance 2.4 inch 320x240 colour displays can be bought for a few £s.They can be driven by modern 32 bit µcontroller boards such as Raspberry Pi Pico, Arduino and others, which are also very cheap.
I am currently working on a couple of projects of this sort. One is a replacement for the analogue meter in an AVO valve tester, which is coming along nicely, and another, which is being sketched out, is to replace the damaged LCD display in a Wavetek function generator.
Away from test equipment the display problem was worse because equipment was being thrown away because of bad displays, even when those displays were generic. I was one of the first people to spot generic LCDs in quite expensive electronic music modules could be replaced by inexpensive and much better LCDs (and now, OLEDs).
Here's my Korg Wavestation A/D after a display swap in 2008, which originally dates from a time when Korg and Yamaha were effectively one company, Yamaha's TG77 uses a similar display and construction. The original display used an electroluminescent backlight which faded over time, leaving the display almost unreadable but cheap LED backlit LCDs were very easy to fit and I know of musicians with little to no electronics knowledge who completed the operation.
A while ago there was someone selling RACAL 1792 LCDs that they'd had made in a small production run, IIRC since that happened it became possible to get one-off LCDs but I think they were quite expensive.
Trolling through Aliexpress, there's a large selection of various kinds of display. It can be a matter of finding one with the right form factor. It may be possible to use a larger one than the original, if there's room. There are libraries in C and Python for most of the chips the displays use. It's nice if the display can be made to give a close representation of the original, but the main thing is that it displays the right information. For instance, although it wouldn't look the same, it might be possible to use a 20x4 character display in the Korg. Obviously, there's no need because there's a plug in replacement.
If you search Aliexpress for "Korg display" a lot comes up. Many look like plug in replacements.
The LCD displays in my Marconi 2019 are OK, but they are known to act up. It would be nice to know a modern replacement was possible.
Magic eye tubes (Y63, 6U5G,EM34) only had a life of a few hundred hours when the display was bright, and are now expensive and hard to find. I haven't really looked into it, but it's occurred that one of the very small, round TFT displays could be used to make a substitute. It seems strange contemplating putting 2020s technology, into a 1940s radio, to replace a valve which was developed in the 1930s, because it was cheaper than a moving coil meter.
synx508 wrote: ↑Fri Jul 18, 2025 8:56 am
Away from test equipment the display problem was worse because equipment was being thrown away because of bad displays, even when those displays were generic. I was one of the first people to spot generic LCDs in quite expensive electronic music modules could be replaced by inexpensive and much better LCDs (and now, OLEDs).
Here's my Korg Wavestation A/D after a display swap in 2008, which originally dates from a time when Korg and Yamaha were effectively one company, Yamaha's TG77 uses a similar display and construction. The original display used an electroluminescent backlight which faded over time, leaving the display almost unreadable but cheap LED backlit LCDs were very easy to fit and I know of musicians with little to no electronics knowledge who completed the operation.
A while ago there was someone selling RACAL 1792 LCDs that they'd had made in a small production run, IIRC since that happened it became possible to get one-off LCDs but I think they were quite expensive.
I did a fair bit of business in this area between about 2000-2009. Dead displays, broken off connectors and cleaning up bong water from keybeds mostly
