ONIKKINEN

The clutch on an AZ-EQ6 is a big friction disk that gets squeezed between the RA gear and the axle when the clutch is locked, but should release when open. It sounds like its just stuck in place after years of use. Its a kind of soft material so it could have fused in between and gotten mangled.

Safest fix would be to open up the mount, and you might as well replace the bearings inside if you have it gutted anyway.

If you dont want to open the mount i have an alternate idea. Loosen up the allen head screws that hold the upper part of the mount to the lower, but dont take them out fully. Remove the polar scope and and loosen the clutch way more than you usually would (a couple full revolutions). Give the locknut under the polar scope a good whack with something soft like a rubber mallet and see if the clutch is released. Its possible you have rust or dried lubricant in there that will need to be taken care of, but try this anyway.

I would advice against using force in the direction of the axles movement, since you could just mangle the stuck clutch disk even more.

6 hours ago, gorann said:

Actually I have not seen Aurora up here at 60°N for many years. We see it as a northern Sweden phenomenon (around 70°N) and nothing to be expected here in the southern half. So clearly this has been a once in a lifetime event with unprecedented sun activity. I am surprised that we have not heard more about disturbances of electronic infrastructure.

I did lose internet briefly, and my car radio was acting up with strong static and weak signal with stations that are normally ok. The peak was at 01:28 on Saturday here in Southern Finland at 60N which also luckily was the darkest hour of the night, and it was easily bright enough to shine through city lights. It was probably still too bright in Sweden at that time since you are an hour behind, so you just barely missed the show because it was still too bright at 00:30 your local time.

I will agree with you that its not that common to see aurora here in the south and you have to go to Lapland to expect to see aurora more often.

37 minutes ago, Elp said:

Monitor refresh rate is different to actual FPS.

See here, an MIT study carried out measured the perceived perception of a frame of information rate at 13ms, which is not far off from 60FPS (it's closer to 1/77). That MIT study is referenced in a number of medical articles.

https://www.healthline.com/health/human-eye-fps#human-vs-animal-vision

If you've ever seen a film in HFR format (high frame rate) which normally is filmed or output at 60FPS the result is jarring as in motion things move too smooth than what we're accustomed to seeing in real life.

Did you read the article or just paste the first thing that google came up with? Quote:

"For example, the authors of a 2014 study out of the Massachusetts Institute of Technology found that the brain can process an image that your eye sees for only 13 milliseconds — a very rapid processing speed. "

Which means 13ms/77fps is the minimum speed required to fool the brain into thinking that the blinked still frames are actually continuous motion, or at least what that study implies. Since if the brain doesnt have enough time to tell that it was a single frame it will be seen as continuous motion (and again, 5s in front of a gaming monitor will show you that we can differentiate smoothness of motion on a screen at a much higher rate).

HFR movies look jarring because for a hundred years we have been accustomed to 24 or 30fps in movies and TV (some telenovelas can be 50, and they look jarrimg as well). If we couldnt see the difference then it would surely not be jarring?

VR is another thing that needs high frame rates in order to mimic real life. Lower than 60fps is nauseating, 90 is ok, and 120+ is good. We should just disagree on this and not derail the thread.

1 hour ago, Elp said:

The human eye typically sees at an equivalent camera frame rate between 25-60 FPS

This isnt true at all, its a myth that keeps getting mentioned online but is not based on any real science. The human eye is capable of seeing at least a few hundred frames per second, just one look at a high refresh rate monitor (mine is 165hz) will confirm that. I can easily see the difference between say a hundred fps and 165. 120vs 165, not sure, would probably fail occasionally in a blind test but that 60fps thing is complete hogwash.

I had to scrap an hour or so from my last years M81/82 image due to aurora gradients (the february 2023 light show). I found that it just ruins the background and makes things difficult, so better to just leave those subs out.

By the way, check the plot tab in Siril after registration and set one of the axis to 'background value'. You will see a plot of the intensity of the auroral display and can calculate how it affected your sky brightness. It could easily have brightened your skies by a factor of 4 or more and temporarily made your bortle rating a couple of values worse.

7 minutes ago, JOC said:

It's most interesting, so what is the camera recording that our eyes aren't?  Is it just down to the longer exposure and more photons hitting the camera sensor (like when you use longer exposures and/or stack exposures) or is the camera actually seeing more light wavelengths than our eyes do in the same way that a mobile phone camera can show the infrared? light from the TV remote that you can't see with your naked eye.  

Cameras are just more sensitive than our eyes, and they build up signal for the duration of the exposure. Even a one second exposure has significantly more light "gathered" than what the live view is naked eye.

There is also the fact that our dark adapted eyes see in monochrome, so if the aurora is faint enough for our eyes to stay dark adapted then colour is not seen.

If i have multiple targets in progress i only shoot the one that is highest at the time to ensure that i get the best possible data. I find that there is a big difference between 40 and 60 degrees in terms of sharpness, so i dont see a point in imaging a suboptimal target if a more optimal target is available. Above 60 degrees is more or less the same, although higher is still better.

This strategy is only for the patient imager, because spreading a season between 5 targets probably means that none of them are "finished" in that year (if one can call an image finished). Hoping to close my M33 project once summer fades out in late August, and its about time since the first subs were taken on 2022.

Some targets are of course always low in the sky, in which case i just pick the least worst time to image.

I see very faint aurora a few times a year from my SQM 21 ish imaging spot, and to an untrained eye it would probably be not at all obvious. Its easy to confirm with a phone camera, if there is what looks like green cloud then it was aurora. Naked eye colour in aurora is more rare, but even then i dont think the average observer would immediately notice.

Within city lights i think all of those will be mistaken for clouds or not seen at all.

17 hours ago, JonHigh said:

Not sure about the horizontal banding  that I’ve not seen before?

I think you are quite a bit underexposed, and thats where the banding came from (its visible in bias frames normally). Or you dont have enough offset and blacks are being clipped (or both, for the latter check that there are no 0 value pixels in short darks or biases).

I think you will need to expose for significantly longer, like 10 minutes or more, at f/12. Depends on your light pollution and read noise at the gain you used but i think 3 minutes is a bit on the low side still.

Doesn't look like there is anything in the options to do this kind of thing.

Try the NINA discord server, if there is someone who knows how to do this (if even possible), then you'll most likely find them there.

4 minutes ago, 900SL said:

Totally clear hear, but hardly any activity. If only I'd had the camera out last night. This was the only activity. lasted ten minutes and was difficult to make out

Similar experience for me, a couple of thin bursts but no spectacular explosion of colour. There will always be the next time, which will be a few times a year here. Although i dont expect to see the cataclysm of yesterday anytime soon.

Some weak purple and green in Finland as well. Hoping to see a surge in activity but we shall see.

10 minutes ago, 900SL said:

Oh wow, this is current situation, never seen this:

 

Im heading to the usual imaging spot to try and see them. Think i'll climb the bird watching tower, should be a pretty good view if skies are clear.

These images capture the feeling of looking straight up during the auroral display very well. Almost like the sky is splitting in half, i wonder if that's just an illusion in the sense that when looking straight up there is the least amount of atmosphere in the way and so it looks like there are holes in the sky.

4 hours ago, 900SL said:

How did I miss this???

Tonight is looking decent too. Some cloud possibly but a good chance of spotting these. For comparison these were on par, or maybe stronger than those amazing lights we saw that one winter night. And thats from bortle 8 - truly bonkers.

Craziest thing i have probably ever seen. City conditions, nautical twilight but still very obvious naked eye purple and green.

The peak was an hour ago, skies have now quieted down a bit.

Images are straight off the phone (Pixel7), no editing at all. 3 or 5 second exposures, not sure, wasn't paying attention too much.

the sky is on fire. Everybody outside right now!

16 minutes ago, Elp said:

South?

The Sun is to the north this time of year and its the brightest part of the sky in a weird backwards sense.

This was just about barely visible to the zenith:

Blue skies and still could see it, very unusual even here.

Just went for a walk, can just about see a faint green glow to the south from bortle 8. City conditions and barely astronomical twilight and still visible, pretty rare for sure.

Skies are clear but couldn't see any an hour ago. Too bright here at 60N, this event is for southern folks to enjoy.

Here is what the Finnish meteorological institute picked up (Nurmijärvi is at 60N and the red dotted line way in the bottom of the graph is the usual visual limit):

I was outside right at that big peak to the right. Would probably have been a decent show in some other time of year, but i shouldn't complain since at 60N i do see them a few times a year.

Great comet image, adds a lot to the also beautiful nebulosity. I like the curved tail, makes it clear this is a moving object.

I feel your pain with the processing thing, i have tried comet imaging 3 times and hated the processing part each time. Each time i swore i would never do it again but of course i did and probably will again when the opportunity arises. But your image looks very nicely processed and not like a fistfight with photoshop these sometimes can (mine do at least).

You can invert images with GIMP to get what you were looking for, and GIMP is free.

Its in Colors -> Invert. You can also desaturate the image to make a black and white image from the same menu.

1 hour ago, WolfieGlos said:

Thanks, I've just looked at the SDSS catalogue....my screen is white with text! I'll have to try and whittle it down a bit to see if I can make it readable and find out what those small fuzzies are. Whilst looking into this, I also spotted another possible galaxy cluster just below M106 in amongst that group of those quasars at 12h+19m.

Speaking of quasars, I created the below image and the text file, sorted it in Excel and the largest redshift in the field is 3.741, located towards the bottom right. I haven't captured it, but I have captured the third largest in the field of 3.321. So if I'm right, using the calculator you linked, this gives 11.784 billion light years ! * My caveat with that, is I have only filled in the Z value, assuming all others are default values that need not be changed, and using the "flat" button, not "open". Not sure what the difference is, but "flat" gives a larger light year value.

I also thought there was an exceptionally bright quasar to the right of +47'20, called "NPM 1G+47.0221". Querying this in Aladin it tells me it's "LEDA 3087510 -- Galaxy", redshift of 0.067.

Fascinating!

Some of those values you can input into the calculator are a matter of debate at the moment and its been dubbed the "crisis in cosmology" or hubble tension, and i think the default values are a few years old so might not be the currently accepted values. Long story short with the crisis is that different methods of getting that value used to be within each others margin of error but more recent measurements show that they no longer are (and some other new data shows that they actually are - its not at all clear). JWST is shedding some light to the issue, at least hopefully. Dr.Becky has made probably a dozen Youtube videos on the subject over the years with a new one every other week when more research is done with JWST data, worth a look if you're interested.

The SDSS catalogue annotation result is a huge mess, a wide (in terms of deep field stuff) field of view will just fill the screen with text. If you tick only the Milliquas catalogue the image should be more or less readable, although you'll still need to cull probably 90% of the results. If you dont see the Milliquas catalogue you can add it from the green + icon. Loads of other catalogues there too, but Milliquas is specifically only quasars.

The z 3.741 quasar has a red magnitude of 21.07 according to the Milliquas catalogue .txt file i have lying around, which i think should just about be detectable. Try giving the linear image a much larger stretch than you normally would? Wont make a pretty image for normal viewing, but the quasar is a couple of pixels anyway and you might just be able to detect it.

41 minutes ago, WolfieGlos said:

I'm not sure how you get this data. Can you do this with the Annotate script  in PI?

You could use the annotation script to get a name for the galaxy (SDSS +telephone number something something usually) and then search that up in Simbad and see if there is a measurement. Sometimes the annotation script can also include redshift if you tick the 'write txt file' thing in the options.

Then you can get a distance with the redshift value using something like this: https://astro.ucla.edu/~wright/CosmoCalc.html

You should try the milliquas catalogue in the PI annotation script, there are some 12+ billion light year quasars in this field that i am sure you have caught with the healthy integration time you have here. I caught a few last year at just 4 hours so you definitely also will since this image goes much deeper than mine did.

Excellent shots. Many nice background galaxies in the M106 image, some quite distant i believe.