ONIKKINEN

8 hours ago, Pixies said:

There is actually a collimation tool that has this kind of concentric ring arrangement built in, no software needed.

That would be the Concenter eyepiece: https://www.firstlightoptics.com/other-collimation-tools/ts-concenter-2-adjustment-eyepiece-for-newtonian-telescopes.html

The view from this towards the secondary looks like so:

There is no room for guessing, i can immediately see that while its pretty good, its not perfect. Since there are a lot of rings you are guaranteed to have a focuser position where the rings are the exact same size as the edge of the secondary. Very easy tool to use, and most importantly very difficult to misunderstand!

In this example the uncoated rough mirror edges are blackened, so its even easier.

You can also collimate the primary with this and there is no need to take offset or mirror center mark into account since the collimation happens using the outer edge of the mirror.

https://ecoflow.com/products/ecoflow-river-portable-power-station

This one will definitely run your laptop from an AC- powerbrick, i ran my fridge with this during a blackout for a test and it does work under heavy loads admirably. Though it wont power a laptop for long probably since the inverter side of the powerbank wastes fair bit of energy.

I seal all of my expensive electronics in a rugged carrying case when outside and only open it after about an hour from bringing it inside. This prevents dew from the temperature difference from forming on them and hopefully makes them last longer. I have 2 cameras, the handset and a mini-pc (and some cables that absolutely must not break) in it. This might not be an issue for most but i have a 40 degree temperature difference between inside and outside at this time of year and everything gets wet immediately when brought inside.

The scope, eyepieces and other optical equipment is left uncapped to dry over night. Sometimes i have to dry my newtonian OTA with a towel if it was very humid outside.

3 minutes ago, cfinn said:

Thank you so much for your reply. I think taking it to a local machine shop is the best plan. I found this place near me. It was just knowing what to search for!

Many thanks again.

Charles

Take the intact tripod bolt with you to the shop and ask them to re-thread with the same threads as the bolt to make sure the correct threads are applied, as @david_taurus83 said it is probably an M12 metric thread.

You can try re-tapping the thread with a thread tap of the right size. Im not certain but i think these are 3/8 inch photothreads.

I would start with a thread file to try and clean what remains of the thread. Start from the back where the threads are most likely still in decent condition. Clean up the thread with the thread file as much as possible before trying to re-tap. Then try to carefully go along the same path where the thread used to be, or you will just end up destroying more of it. It will never be the same again with retapped threads of the same size since a lot of the material was lost, but it could work if you dont use too much force when threading into the mount again.

There are also thread inserts that you could try to drill into the existing hole but this i wouldn't try myself if i wasn't comfortable with this kind of thing.

The thread file and a thread tap + wrench will cost you not that much, but isn't guaranteed to work. But also probably wont make things worse. The best bet would be to take the mount to a local machine shop and ask them about refitting a threaded insert to the hole. Its not a huge ordeal and probably not that expensive. Its far from completely destroyed so entirely fixable.

36 minutes ago, Jjmorris90 said:

Aha i will give it a Go. Thanks for looking. 
 

il block the viewfinder next time. And how can I take flats at night? 
 

thanks 

Most folks use light panels of some sort. Its an extra trinket to carry out and set up but worth it in my opinion since flats are probably the most important type of calibration frame.

There are expensive options: https://www.teleskop-express.de/shop/index.php/cat/c229_Flat-Field-foils-and-boxes.html

And cheap options: https://www.amazon.co.uk/Drawing-Tracing-Ultra-Thin-Adjustable-Brightness/dp/B072F8T5FH/ref=sr_1_29?crid=12P09PNJDKODH&keywords=agptek+light+panel&qid=1641750123&s=kitchen&sprefix=agptek+light+panel%2Ckitchen%2C83&sr=1-29

I use the latter. These cheap drawing tracing tablets feel like toys and probably wont last long but they are very cheap and do the same thing. The dedicated flat field panels are dimmable to whatever level you want and some can work with capture software (like NINA) to automatically take the ideal flat exposure.

9 minutes ago, Jjmorris90 said:

sure, here. 

thank you  

result.fit 207.18 MB · 0 downloads

The gradient is blotchy and difficult to remove. I end up with a similar result as you with most methods. I could probably brute force this with GradientXterminator plugin in Photoshop, but it looks difficult to deal with. Looks a lot like a light leak to the sensor somehow IMO. Also since you are using a newtonian it is possible your collimation has changed since shooting the lights and taking the flats, which is why flats are best taken straight after the session.

This needs to be blocked so that no light can enter during shooting. It could be the culprit here.

But one more thing you can try other than re-shoot the frames is to do the background extraction per sub. This works well for linear gradients, but if each sub has a nonlinear gradient due to light leaks it may not work that well.

To do this you should use the "seqsubsky" command in Siril before stacking. After pre-processing you can run this command by inputting "seqsubsky pp_light 1" to the console. In here seqsubsky is the command, pp_light is the sequence name in question and 1 is the degree order of the extraction. 1 is linear 2 is less linear etc, usually only the first order extraction works well for individual subs.

If you used one of the scripts built in to Siril to do the whole process you can add the command line in to the script you used. You can open the .SSF files with Windows word pad.

I am not quite sure to which point the command goes, but it might be the one i marked.

An easier way (which i use) would be to use Sirilic, a software that uses Siril for stacking but makes all the data usage much simpler with a drag and drop interface. No need to manually faff with folders with Sirilic.

Here: https://siril.org/docs/sirilic/#download

In Sirilic the "subsky" command does the background extraction per sub. Set to 0 for no extraction, 1 for linear extraction. Higher than 1 will probably not work well but you could always try.

Its a lot to think about, sorry if it sounds like im rambling 😅

Attention everyone having USB issues!

I just received a brand new AZ-EQ6 and the Prolific USB to Serial drivers from Skywatchers site DO NOT work with the mount. Skywatcher is probably using whatever chips they have on hand due to the global chip shortages and have failed to update the driver download section on their website.

I had to manually install the newest version of Prolific drivers for the handset OR mount USB connectors to be picked up by device manager as working COM ports.

Here are the correct drivers: http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=225&pcid=41

Difficult to tell from the screenshot if something is wrong, can you post the raw stack?

Im banking towards background extraction going wrong. I use Siril a lot and sometimes its just difficult to use and should be done on the individual subs before stacking. There is a method to do this in Siril with the seqsubsky console command but i would like to try on the stack first if thats ok.

4 minutes ago, Jjmorris90 said:

sure. here is one of the flats. 

IMG_2741.CR2 24.59 MB · 1 download

No problems with the flat. Nicely illuminated with no overexposed pixels at all. There are some 0-value pixels in the red channel but i dont think its the issue here. Not sure how to go about fixing that either, maybe trying to take a longer exposure flat by dimming down the light source since this is a 1/200s flat exposure? A couple of T-shirt layers more with sky flats or the monitor method with a dimmable light source, but anyway thats beside the point.

You get this view in Siril by putting the preview mode to "Histogram" in the bottom and selecting the rainbow false color mode from the bottom tool panel. Very easy to see what is what especially with flats. This is a pretty good flat although the optical axis is not exactly center to the camera (collimation or tilt).

Do you get the gray uneven blotches on the raw stack before background extraction?

Ill go with either a) light leaks during capture (difficult to remove) or b) something wrong with the background removal process.

4 minutes ago, Jjmorris90 said:

I took the flats by pointing the scope at the sky and covering it with a white T-shirt. I used AV mode. Same iso. Camera determined shutter speed 

Can you attach the raw flat file so i could have a look?

That is a good method by the way, unless the sky was somehow unevenly lit at the time. AV mode in DSLRs always produced decently illuminated flats for me so i wouldn't worry about the method. But if you want to test another method you can just point the camera and telescope (or lens or whatever) to a computer screen/tv/tablet that is showing a white screen with the minimum brightness setting. Take at least 30 flats and move the telescope around the screen and rotate it in your hands during this to make any possible defects in the screen even out in stacking.

Looks a bit like light leak from the viewfinder if you used a DSLR. The viewfinder is a light pathway to the sensor and some light will leak there if its not blocked.

On my first session out with a DSLR i had a red light headlamp on pretty much the whole night and occasionally i would point it towards the camera. It left a red blotch on all the frames that looks a lot like what you have here. This would not be removable with flats and would conveniently explain why the weird shape remains after taking flats. Or could just be that the flats you took were not that great, so how did you take the flats?

12 hours ago, vlaiv said:

Another thing that can create asymmetric flats is type of scope. Newtonian scopes and especially fast newtonians have asymmetric flats (there is some secondary offset that I don't really understand - never bothered to properly grasp it since I never owned fast newtonian)

This looks like the secondary mirror was not perfectly centered under the focuser, which in my experience causes asymmetric flats (and other issues).

Take a look at some examples from my previous flats. These screenshots have been taken with the false color and histogram preview modes in Siril, very quick to see differences. Also there is a change of camera, hence the very different look to them.

One of the first flats i ever took, in almost stock collimation with my VX8 which after inspection with proper tools i found to be not well centered. Not a huge change in collimation, but a huge effect. On the bottom we see shutter shadow from a DSLR not quite being fast enough for flats. On the left side we see the same thing as in your example, an asymmetric brightess change.

One of my more recent flats with care taken to achieve as good a collimation as i can, but you can still see the red bright regions are not perfectly centered and probably some tilt remains. But the asymmetry is mostly gone because i centered the secondary with a concenter eyepiece. Also, this process includes adjusting the focuser and not just the secondary so yes one could say the secondary and focuser were out of collimation.

4 hours ago, ollypenrice said:

🤣  That would be me. 🤣

In fact I don't think it's bad, I think it's good unless it causes the plate solver to disconnect their brain and throw it in the garden pond, as it sometimes does. We've seen people post images of some bit of random sky and say, 'I can't see M51 in this image even though I spent four hours collecting data on it,' or,  'I used plate solving to shoot these two mosaic panels but the software refuses to join them,' when it is perfectly obvious that they don't overlap, whatever the plate solution tells them.

Plate solving is fine but inevitably it introduces an extra piece of software, sometimes two. Sometimes there are eight rigs imaging at my place and what goes wrong most frequently? Software. And in second place? Software. So use it by all means but don't waste time faffing around getting it to work under a nice clear sky.

Olly

Might be you 😁.

We definitely agree on the brain part, but i think this issue also exists without platesolving. Just as well one could do 3 star alignment perfectly, slew to target and go to sleep and wake up the next day to unusable frames, in fact i think this is more likely without platesolving since you are just using your eyes to determine whether or not you have the target framed. If its an obscure/dim target with poorly defined edges and hard to recognize features its very likely you will end up missing and failing. I have a running project where i am shooting IFN that is only visible after about 2 hours of integration and there isn't even a hint of this structure in a single sub so i could never frame it properly without platesolving. Also this area of the sky has few defining features that could be used as pointers so not helpful to just eyeball these things. I had the camera at an angle of 82 degrees instead of 90 on the first session, so no i will have to check every time that the platesolver does indeed report the 82 degrees and once it does im all set and the framing can not fail. I think platesolving is 90% solutions to problems and 10% possible added problems with software (which will definitely happen at one point). If one follows what the platesolver is doing and understand the parameters that must be set for it to do what you want, it will end up saving about an hour per session and almost never cause problems.

@ollypenrice @malc-c This talk about Argonavis control systems and permanent observatories is a solution to most problems, including this one. If the setup is made of premium parts (Argonavis is in the Mesu?) and permanently placed then the align points would be faster and better as it introduces no extra spanners in the works. This way also every night works the same, as the mount is fixed in an observatory and not moved each night so the alignment points do not have to be remade.

For most users though who set up and tear down each night, or at the very least carry the mount in one go already assembled from a shed/from indoors will absolutely find platesolving a blessing and a solution to many problems including the one OP is having.

1 hour ago, adyj1 said:

Not familiar with Argo Navis but it must be heaps better than my eq5 😉 . I always had to do small tweaks after the goto, needing me to take exposures and adjust, which all took time. With platesolving it is much quicker than me and also more accurate 😁 

I can understand that the better the kit the less the computer correction would be needed. 

Same was with my EQM35, i could do 3 star alignment perfectly with a star exactly centered on my DSLR crosshairs and still have a +/-10 arcminute deviation from where its supposed to point, which would be easily enough to ruin most targets. That would be because the pointing accuracy of Synscan mounts are quoted as 6 arcminutes at best.

I received a Skywatcher product today (AZEQ6) and with it came a leaflet with Skywatcher products advertised in it. I noticed that there is a mount that i do not recognize at all. Doesn't look like anything from Skywatchers current catalogue, is it a new mount?

Looks very similar to my shots when i had focuser sag/collimation issues with my newtonian. Dont know if collimation can be an issue with your refractor but focuser sag or tilt somewhere in the camera-corrector-focuser area would look like this.

Increasing gain will not be bringing fainter stuff in, it will just make brighter stars saturate faster and make the image look brighter. Higher gain has a lower read noise but with exposures as long as yours it really doesn't matter any more with modern CMOS cameras. I personally wouldnt take longer exposures than the ones you are already taking as it increases the chances of losing more data due to wind/mechanical issues etc. Your camera is pretty good so longer than 60s exposures are pretty much guaranteed to be sky-limited unless shooting narrowband, hence almost no benefits from longer subs.

You did not mention using a filter (H-alpha/O3/both) with your setup, but using a narrowband filter would make the image be better much faster. Many such filters out there for colour cameras like the Optolong L-extreme. Also, the kind of sky conditions (light pollution, etc) you image from will dramatically increase or decrease the time required to reach a good looking result in the end. But could also just be not quite enough integration.

But in the end its difficult to say without seeing the picture first, mind posting what you are working with now as it is?

Postman brought 2 very heavy boxes. Didn't include rocks as i first believed!

Feels very solidly built unlike my previous Skywatcher mount 👍.

Unfortunately wont be using this for a while as i seem to have finally gotten the C(not from the postman that one).

1 hour ago, oymd said:

 

 

I would like to start by thanking everyone on this thread!

You have helped me immensely.

I think I also missed quoting @AstroKeith

So, I disassembled the mount tonight.
 

There was a large amount of RUST and the Dec axis was frozen at the part just above the clutch.
 

There was a fair amount of rust on the OUTSIDE OF THE CW BAR HOUSING and the INSIDE OF THE OPENING WHERE THE CW HOUSING EXITS THE MOUNT.

Now, you might ask, why the heck is there so much rust centered on the most dependant part it the mount?

I now can deduce what exactly happened?

Back in November last year, on my LAST imaging session, I left the mount outside in the garden to complete about 5 hours on the Rosette.

I planned to wake up early BEFORE the sprinklers came on in the garden at about 6am.
 

I did wake up on time, but I just missed the sprinklers by about 30 seconds.
 

There was very light water on the BOTTOM of the mount and tripod, but I managed to carry it back onto the porch away from the water.
 

I used my endoscope then to check inside the mount, and I could not see any water ingress, so did not really bother.
 

On looking on the OUTSIDE of the mount, there was some moist and damp at the area of the clutch.
 

I was travelling back to London in 48 hours, and had no plans to image again.
 

I used a hair blow dryer for about 20 minutes on the clutch area, and also wrapped it with a dew heater band for about 24 hours on maximum setting.
 

I travelled the next day, and COMPLETELY FORGOT ABOUT THE INCIDENT till I saw the rust tonight!!!

There must have been some ingress at the clutch area, and it had a full 40 days or so to rust happily until I tried to balance the Esprit a couple of days ago! 
 

I never gave the sprinklers incident a second thought, and I believed I got away with it!

Anyways, the reason that there was a few degrees of rotation, and then a KNOCK, is that there was rust seizing some kind of bearing on the INSIDE of the opening at the BOTTOM of the mount where the counter weight bar exits the mount. 
 

Tonght I could rotate it with my hand about a 10th of a full rotation either way, and then it would grind to a halt. 
 

I spend a good 4-5 hours brushing all the surfaces showing rust with a scotch brite sponge and a toothbrush with PLENTY of WD40

Everything was smooth and clean at the end  

As advised, I used White Lithium grease on all surfaces, and indeed, everything is smooth as butter now. 
 

Connected the mount in NINA, and slewed in all directions, sorted out the backlash and no binding to report. 
 

Will try an imaging session tomorrow. 
 

THANK YOU EVERYONE

Especially, thanks @wimvb

 

Thanks for the recap, it all makes sense now how this happened! The rust markings are only on one spot, presumably the spot that was towards the ground when the mount was sitting for 40 days. I think if it had been in use faster after the water damage, this wouldn't have been nearly as bad or even rusted at all since the water could have had a chance to drain off.

30 minutes ago, gorann said:

Had quite a few clear nights here at 60°N in Sweden over X-mas and New Year but tonight seems to be the last one for a while. Right now I have my dual-RASA8 rig aiming at a very dim nebula known as MBM13 near Auriga. I got a Samyang 135 piggybacking, so three ASI2600MC collecting data. And I play it safe so each one got its own laptop - never had any luck with having one laptop connected to two cameras.

PS. The towel on the counter weights is to stop any dew dropping into the laptops  - I had a close call.

Cheers & CS

Göran

Clear nights are rare? Just use 3 telescopes at once. looks like you have figured out the weather problem just fine 🤣

1 hour ago, oymd said:

I’ve brushed it well. It’s rolling freely. 
 

What is this ring btw?

is this the encoder ring?

are these markers encoders or rust marks?

Looks like rust damage

1 minute ago, Peter Reader said:

The FITS open in DSS and from memory the meta data for ISO and exposure time was available to the software. Also true that I cannot view the fits files in windows photo viewer so canon CR2 would be better for that...

Then they would probably work just fine. But one more tip i will give about the.FITS files not being viewable easily: They dont have to be viewed!

In NINA you can set various parameters to be written on the file name itself and so can inspect all the useful information of the sub without opening it. You'll find this in the options-Imaging tab.  Example below:

In this image you can see a screenshot of the folder i have saved my subs. The file name consist of the time and date it was taken on, then the exposure time, then the number in the sequence it was taken on. The next number, for example on the top one 1.15 is the guiding error in RMS arcseconds from the duration of the sub, not the total error of the session mind you. Next line is the name of the sequence that i had created. The final 2 numbers are HFR being 3.77 in the top example and the number of stars NINA detected and used for this HFR measurement. If these values are clear outliers from the average sub, then probably a good idea to just throw it away.

Just by glancing at this list i can immediately tell that there are some clear outliers that should not be used for stacking because either the guide error or HFR was too high (for example the HFR 4+ subs are not good). This way i dont need to inspect the sub itself and can just remove it from the list without much worry on losing data. I find this to be an essential method when there can be hundreds of subs after a night to inspect.

4 minutes ago, Peter Reader said:

Had a much better session yesterday evening after re-collimating and spending more time focusing with bahtinov mask: 

Yes I definitely had coma but I think it's pretty much sorted now with the corrector. Do you see any issues with my images linked above? Images came out pretty well, although some questions remain...

Thanks for your detailed response. Is the Native Canon driver something I need to download from Canon's website? I don't see the option to connect to anything other than ASCOM DSLR in NINA. And is there any reason to switch from fits to the canon CR2?

Thanks I will try this next time for sure.

They might still be a bit out of focus, hard to tell if its processing or just slightly big stars due to focus, but coma is gone.

I just see a Canon driver option in NINA. Have not downloaded anything from Canon, thats for sure. I think this is just on NINAs end to deal with the driver? I dont see this option straight away by the way. I must plug in the camera and then click the refresh button for this option to appear. Also, the camera must be set to manual shooting mode first.

Can you use the FITS files as you would raw files, as in they are debayerable and have usable header information (ISO or gain/exposure time)? If you can, then im not sure there is a benefit to having the files be in .CR2 format. One benefit might be that .CR2 format files are easy to open and browse through in windows where as .FITS files really are not.

3 minutes ago, Peter Reader said:

I also re-collimated the telescope and spent a while with Bahtinov mask to get focus correct but will check out NINA's star analysis next time for sure. This was my first evening with the coma corrector and that also seems to be doing a great job compared to before...

Coma corrector is doing great 👍, very nice images for such short integrations. Actually just nice looking images even without considering the integration.

I focused with a bahtinov mask for a few dozen sessions but then switched to just using NINA HFR readings. Takes maybe a bit more time (not always) but i am guaranteed good focus. It can be difficult to tell by eye whether the bahtinov mask diffraction pattern is truly centered or not, and changing seeing can make this difficult. I found that i could reach what i thought was good focus with a bahtinov mask but still improve it after taking the mask off and doing tiny adjustments with my 1:10 reducer gear in the focuser. Your mileage may vary, but i dont trust my bahtinov mask anymore.

1 minute ago, oymd said:

Done. 

Does the dark stuff not come off? Difficult to tell without handling the bearing myself but looks slightly oxidized. If it feels slick when rolling then nothing to worry about, but if you can feel the dark stuff with your fingers or when rolling the bearing it should be taken off.