ONIKKINEN

Its worth it to try to get Siril to work for you and it doesn't really take that much getting used to. The easiest way is to use the premade OSC preprocessing script found in Siril. Just create a folder on a drive that has plenty of free space on it (and make this the "home folder" for Siril), create 4 subfolders named lights, darks, biases and flats and then put all the raw frames on these folders and click the script. Siril converts your CR2 files to .fits files and then calibrates them and stacks them. It really is that simple.

Check this tutorial if it still doesn't make sense: https://siril.org/tutorials/first-steps/

If you want to have a drag and drop kind of experience like with DSS you can use Sirilic, which uses Siril to do the stacking but with a simple to use graphical interface.

Check it out here: https://siril.org/docs/sirilic/#the-first-steps-with-sirilic

With Sirilic you can do lots of things you cant really do with DSS, like removing background gradients per subframe (subsky) before stacking which helps a lot if you had an unusually strong gradient for some reason.

I would love to see it, whether its trouble for astronomy or not. Also, since i live at 60 degrees north, betelgeuse is always low in the sky or not visible at all, so i would mostly dodge the worst negative effects.

Since its so far away i doubt it would have any observable detail other than a very bright star for years and years. During my lifetime? Dont know. Someone more knowledgeable on the supernova remnant expansion rate could probably answer that.

2x2 panel mosaic with an additional center panel for stitching the panels together. 60x30s per panel, except for the center which was 10x30s so in total 2h5min of integration. Shot with a RisingCam IMX571 OSC camera in a VX8 riding on an EQM35.

Captured last august and the image had some star shape issues due to guiding, focuser slop and a poor quality baader M48 extension that did not thread properly so i had to reduce the size quite a bit. Stacked at 0.5 scale in APP and then further binned 2x2 as an attempt to hide the issues. Further processed in Siril and Photoshop utilizing Starnet++V2 for some minor separate star layer, background and galaxy layer tweaks.

9 minutes ago, oymd said:

Many thanks

Can you please advise me how to populate my Dither settings to fix this issue?

I think you can drop the settle timeout and min settle time to much lower, like maybe 10 and 10 seconds. Your guiding looks pretty good and stable so i dont think you benefit from having the times be so long.

I am not sure however how to change the settling limits setting. I would assume that its the 1.5 pixels you have set in NINA but the guide logs say otherwise. Never had this issue myself so not quite sure how to fix it, but this doesn't really make the dithering fail and just prolongs the settle time unnecessarily so not the main issue here.

If dithering failed for some reason and its not apparent in the logs you can see it if you blink the frames in Pixinsight before registering them. Just blink a bunch of the frames and you should see a very obvious sudden jerk when dithering happens and if it does not happen well then dithering did not happen for some reason.

To me it looks like the dithers do happen on schedule and like they should. The log says your settling has failed, but i dont think that has to do with dithering success but is just the result of your settings.

You have here the dither spike as it should in the directions ordered. The "settling failed" notification is there i think because you have a high settling time of 120 and strict settling limits. Not sure why your settling limits in the log appear to be less than 1'' but they are set as 1.5 pixels in NINA which would obviously be a lot more than that 🧐. I dont think this has anything to do with your issue, but this does waste 55 seconds after a dither. Im pretty sure NINA starts the next exposure only after PHD2 informs NINA that settling has completed, and since it fails for you every time it has to wait the 55s you have set it to in the settle timeout setting.

1 minute ago, oymd said:

I’m also attaching the PHD2 guide log. 

Sorry, you do not have permission for that!.html 49.3 kB · 2 downloads

.html file format? Something went wrong, its supposed to be a .txt file

I cant see the problem in the raw subs. Also cant open the .xisf files so cant check the masters, but from the looks of your screenshot it does look like walking noise. It could also be the result of some funny sigma clipping issue where a bad sub is chosen as the reference by the stacker and so a lot of good data that deviates from the bad sub gets rejected in the end. I had this happen with deep sky stacker once, but not sure if its all that common of a problem.

Your dithering schedule looks good, i dont think i would bother dithering more often. I dither every 10 subs when i shoot 30s ones, so every 5 minutes as well. I also dither in RA only and it still works well like this so not sure whats the problem. Can you check your PHD2 logs and see if the dithering actually took place? And if it did, how many pixels was the dithering set to. If your dithers are very small, like maybe 1 or 2 pixels i think they might not work that well with OSC cameras.

2 hours ago, ONIKKINEN said:

Take new flats with the same focus position and stack with those. Set the lens at the same focal length and get it to infinity focus either by using stars or something far away in daylight and then shoot the flats.

You can take a few different sets of flats with slightly different focus and focal length positions and check if one of them works. I would say its almost certain you can take flats that are much better than nothing and you can salvage the data. In the future try to shoot flats before the battery runs out, they are almost as important as the light frames themselves and you really do need them.

If you dont want to do that for some reason, or cant get them to work properly you can try the background extraction tool in Siril (free). It doesn't always work like i want to but it will definitely help with your vignetting here. I ran your pic through it:

The quality is not great because i just used your cropped screenshot JPEG, but it still worked a bit. Would expect it to work much better with the linear 32bit file straight off the stacker. If you try it out, i would recommend trying out Siril for other processing too, its much better than manual slider fiddling with GIMP/photoshop.

Hmm, for some reason i did not notice that the original post had a link to the stacked file...

Well, anyway ran it through Siril and some photoshop fiddling afterwards:

Background extraction as a first step to the linear file worked very well and the image is perfectly salvageable. I stretched it a bit too far here, but this is a quick edit that shows you can work with the data without flats in this case, if necessary.

Take new flats with the same focus position and stack with those. Set the lens at the same focal length and get it to infinity focus either by using stars or something far away in daylight and then shoot the flats.

You can take a few different sets of flats with slightly different focus and focal length positions and check if one of them works. I would say its almost certain you can take flats that are much better than nothing and you can salvage the data. In the future try to shoot flats before the battery runs out, they are almost as important as the light frames themselves and you really do need them.

If you dont want to do that for some reason, or cant get them to work properly you can try the background extraction tool in Siril (free). It doesn't always work like i want to but it will definitely help with your vignetting here. I ran your pic through it:

The quality is not great because i just used your cropped screenshot JPEG, but it still worked a bit. Would expect it to work much better with the linear 32bit file straight off the stacker. If you try it out, i would recommend trying out Siril for other processing too, its much better than manual slider fiddling with GIMP/photoshop.

On 12/01/2022 at 02:09, Sunshine said:

Roman Space Telescope set to launch some 3-5 years from now.

Hmm.

Not going to hold my breath on this estimate, if the schedule of JWST has taught me anything. Maybe RST(?) will become as famous as JWST if it gets delayed for half a decade too?

Tennis is a hobby that can be as expensive as you want it to be, so i think the comparison to astronomy is quite good.

Just renting a court and playing with a friend is not really that expensive, even if you do it a couple times a week. Equipment doesn't have to be top tier, really any decent racket and balls will do. But the thing that is expensive is the lessons you will probably want to take, if you have never played tennis, and this is quite expensive and not something i would want to pay out of pocket. I used to play tennis and i got the feeling that there were the casual normal players and then the super enthusiast i-must-get-better types of players and the teaching was mostly focused on pushing everyone to the latter category. There was also a bit of pressure to take more lessons and make tennis my only hobby, which it wasn't at the time so i just quit in the end. I do get the feeling that tennis is a bit of an elite sport if you take it far enough, but if you just play with friends casually then not. Actually come to think of it the logic applies to most sports hobbies i can think of.

3 hours ago, Wonderweb said:

I have an eq6r pro which I will be putting in my observatory when I get round to building it. In the mean time I use it on my back yard. I currently have an rc6 which is a swine to collimate and im never fully happy with. I would be willing to go up to around £1000 for the right scope. 

Hmm, for new scopes there isn't much to choose from at this price point. Looking at SCTs you could get a 6'' SCT but honestly i would think the RC6 is a better performer if it held collimation. You could get a 200PDS with money left over for a good coma corrector and some other bits and that would make a pretty fast galaxy scope, but since its a newtonian you would still have to deal with keeping the thing collimated and possibly remedy some other newtonian issues. For used scopes, well anything goes since prices are not set in stone.

If you do have a deal on a C9.25 that you could get for a price you like, you can use it with the 0.63x reducer with your current camera, provided that you bin or sample accordingly with other means, like super pixel debayering. So if you dont want to upgrade your camera for other reasons, know that you dont really have to. With the 0.63x you would still fit M33 comfortably on the 269, and everything other than M31 will be smaller than this so i would say its good to go.

What sort of budget are we looking at here?

What mount will the scope be put on, and where (observatory/traveler/backyard etc)?

Not sure how to advice without knowing these first.

Have a look at Siril: https://siril.org/

Its free and easy to use (for an astronomy software that is...). You can use it to preprocess and stack your images, but also do some post processing. Stretching and colour balancing especially in this software is just a couple of clicks, and will definitely be easier to do than manual fiddling with sliders in GIMP/Photoshop/some other non-astro software.

Love it 👍.

Rich backgtound too. Holberg IX actually has some nice detail and there seems to be a faint background galaxy everywhere i look in the image.

I kinda like the "dreamy" look when zoomed in with the sharp foreground and the distant slightly defocused stars. Gives the image a sense of grand scale IMO.

If its just a uniform colour of light pollution over your images it goes away with just colourbalancing. Have not used Affinity but in Photoshop you can do this with either levels, curves, the colour balance tool or all 3. Or the auto-colour and auto-tone options.

Try to bring your histogram peaks together like this:

Now this isnt "done" yet because its far too blue but that's the gist of it, to be honest i never learned to do this properly manually as there are tools that are infinitely better than this available for free. Dont be afraid of the beige cast on images, its very much normal unless you're imaging from a very dark site and its something that just goes away with colour balancing.

But it would be better to start using dedicated astronomy software as soon as possible as this kind of manual fiddling with sliders will just not get the same result as a tool meant to do that. There are some really simple and free software to choose from that do this kind of thing much better.

For stacking: Deep sky stacker and SiriL. Deep sky stacker preprocesses and stacks your images and is very simple to use for even beginners. SiriL is maybe a bit less simple to use but you can preprocess, stack and process the image using it. You could also stack in DSS and then process the stack in Siril, and then do final touchups in Affinity or PS.

SiriL has a gradient removal tool that attempts to fix gradients if your image has them. From B7 or 8 i would say its almost guaranteed you do have them so this step is quite useful or in many cases absolutely necessary to get a presentable image in the end. Once the gradient is fixed you can run the Photometric colour calibration tool which looks at your image, detects which stars are in your image and then looks up their colours from a photometric catalogue and attempts to match your image colours to the catalogue colours. It works extremely well for most types of images. There is also a manual colour balance tool where you just select a box that represents background and select a box which represents a white spot, like a white/yellow star or in the case of a galaxy you could select the entire galaxy.

The filters you are thinking of are situation dependent. For emission nebulae, like M42 you will benefit from narrowband filters such as the L-extreme. For broadband targets, like galaxies you do not benefit from these kinds of filters as there is no specific wavelength you can pick and choose to get the best result. For galaxy imaging the best choice is to just deal with the light pollution and capture through it, with no specific filter. If the conditions are really bad -  like inner city bad you might want to use a broad-ish light pollution filter like an L-pro, or some other similar filter. But you should know that using this kind of filter removes the possibility of getting a true colour galaxy image in the end as you have cut off a big chunk of the actual signal along with the unwanted light pollution signal. I would advice against such a filter for galaxy imaging, but for nebulae the L-extreme or similar would make a big difference.

I was thinking of maybe getting one of these, or a similar size from other brands as a second scope to keep me busy while my main scope is imaging. The weight is a bit concerning though as i would want to mount it on some low effort manual alt-az mount like an AZ4 or AZ5. Difficult to tell without handling one in person but would you say its a bit too optimistic to think i could get away with that or better to go for maybe a 100mm one?

On the contrary, i think its becoming cheaper and cheaper every day.

DSLRs are better and cheaper than they were 10 years ago, but dedicated astronomy cameras are also cheapening all the time. Right now there is some healthy competition in the camera market and you can get some very good cameras for not that much money. I wasn't in the hobby 5 years ago but looking at what some older models (like ATIK cameras) cost now it looks like the price to sensor area ratio has improved a lot. Also nowadays we have many cheap OSC narrowband filters like the Optolong L-extreme that bring the entry cost to narrowband imaging down by about 2000eur. Of course OSC+ duoband filter is not the same as mono camera + 3nm narrowband filter set but its in the same category at least and for a fraction of the price. Basic scopes and mounts are already pretty cheap and i doubt competition can bring this price down that much. Acquaintance of mine is into normal photography and he was amazed at how cheap some kit is, i mean you cant really get even a half-decent lens for 300eur but you can get a 130PDS with that, and that's already a pretty good scope.

Most tools used in the capture and post capture process are available for free and you can do pretty much anything without dropping a single cent on software, which is not how it could be. Right now i guide my telescope using PHD2, run my mount and camera with NINA using the built in USB connection that all new Skywatcher mounts have, preprocess and stack using Siril. All of these tools are free and work as well as the paid options. Sure the best software for processing (Pixinsight) costs a lot of money, but IMO beginners wont be needing that for a long time.

You can get a pretty decent setup for astrophotography (one you wont immediately regret) for as little as 1000eur, but would be better to have a bit more. This kind of price is in my opinion not outside most peoples reach. Of course there are differences in countries for what you can realistically afford as a worker but i think this applies to many of the most commonly seen nationalities here. If i think about my previous hobbies i dont think astrophotography is really that expensive compared to them. I used to ride/tune/tweak/upgrade motorcycles and it was around the same cost, i was really fanatically into gaming PCs a while back and of course this costs an arm and a leg as well. Even non-hobby items like smart phones and other consumer electronics are in this kind of pricerange. So if one can imagine owning a decent new-ish smartphone, a gaming console or PC then they could just as well own an astrophotography setup.

All of my kit has been bought on a warehouse worker salary, which i think most will agree is on the lower end of the salary ladder and not something you'd expect the typical astrophotographer to do. I started with an Astromaster 130 because it was 300eur, which was an amount of money i could lose and it would not be a disaster. Of course its not a good scope but it was good enough for me to want better and got me hooked so it did its job.

I had the exact same thing happen with DSS, all of my images were stacked on one trailed image and it looked a bit like yours. Was going mad with this and tried lowering the stack best % setting and did not work. After going through all the subs visually i found that the highest score frame was the one bad frame.

Since then i make NINA write some statistics of the sub to the filename itself, so that i dont have to visually inspect a thousand fits files.

Along time and date, exposure time and the usual stuff i have NINA write guiding RMS error from the duration of the sub, star HFR and number of stars in the frame. Without looking at the subs themselves i can see a few obvious outliers in the below list and i just delete them without thinking about it too much. This removes most of the obviously unsuitable images before stacking.

This is what i got from a quick composite in Siril and some stuff in PS:

Like @AKB above i think your focus is a bit soft, or some other issues make the image soft. Stars are 5'' FWHM which is definitely too high for this kind of tight crop high resolution work. Either focus, guiding, seeing or all 3 need to be looked at to get to the root of the issue.

Colour is there, but i think you would need to invest a lot more integration time to ease the noise in the image and make it easier to pull out. Up to you to decide whats enough and whats good enough, but i would try to get some more.

Also, you had some serious rotational issues in your capture that means the already small image has to be further reduced in size:

You would need to spend some time making sure you have the same camera rotation in each session if you dont want to have to further crop the image.

You also have many hot and cold pixels left in the image, which i find a bit strange for a stacked image. Either you did not dither, darks did not remove them, or both. Not a huge deal, but since you were wondering about calibration thought i would point that out.

On 09/02/2022 at 00:41, recceranger said:

When I stacked the images and brought the final image into Ps, I had to do some brutal levels and curves adjustments to even see the galaxy in the frame. It was worse when I attempted to stack M51 in DSS, where the number of stars detected was just 16! DSS could not stack the 40 or so images that I spent the night capturing. When I switched to my Nikon D7500 and took light frames each for 180sec at ISO800, DSS detected hundreds of stars and stacking was seamless. Has anyone encountered this using a similar setup?

The necessity to do a brutal stretch is not a problem, but it is a bit of a problem in this case if you use photoshop for all processing. I would recommend doing some things to the stack in Siril first and then moving the partly processed file to photoshop for the final adjustments (which is often most of the work). You can do a background extraction if necessary, photometric colour calibration and then stretch the image to what you like in Siril. But this has nothing to do with the star issue, just pointed out that with files that need a lot of stretching it can seem "wrong" with the way you need to do it in PS and there are better alternatives.

The star detection issue is hard to advice on without seeing the raw frame itself, but i will guess it has to do with sampling rate/star size and so DSS doesn't count the stars in your images as stars because they are spread over too many pixels. Sampling rate is just a part of this though, seeing and your guiding performance will also effect this.

Try the super pixel debayering setting in DSS and see if it detects more stars:

If that doesn't work, could you attach one raw frame here so we could have a look?

20 hours ago, Stu said:

Do the timings stack up for it to be related to this one? Looks quite like 40 odd small satellites re-entering?

https://news.sky.com/video/share-12535287

SpaceX Falcon 9 second stage, but launched in 2017: https://www.space.com/spacex-rocket-stage-deorbits-over-mexico

All second stages that have not been shot to escape trajectories go through this, but most re-enter somewhere they are never seen because the Earth is mostly ocean. The second stage has many metal parts built for high temperatures that take a long time to burn in the atmosphere so this sort of lightshow can remain for a while (like all engine parts which generally benefit from not melting in use, also means they resist re-entry shock heating for a while).

Some kit can make its way to the ground after re-entry: https://www.theverge.com/2021/4/2/22364582/spacex-rocket-debris-falls-farm-washington

By the way this is the reason why SpaceX launches starlink to initial low orbits, because this second stage has been nothing but space junk for 5 years, which the starlink satellites would also be if shot to initial higher orbits.

This is how my stuff is stored if i expect to have suitable weather so i can leave right away. Everything is pre packed and i dont have to check anything and can just haul the gear to my car and set off. I push some of this under the bed usually though, but everything is packed as in the picture. I live in a tiny flat so floor space is not a luxury i have but what little there is left i have dedicated to astronomy gear (naturally).

Not sure how much all of this weighs, but probably around 50-55kg. I carry these to my car in 2 trips. I am pretty sure i cant have a single piece of kit more and still get away with 2 trips, whatever i buy next will need to be hauled separately. Its a struggle if my apartment building elevator is broken (sometimes is) and i have to carry everything down from my 6th story flat 😬.

But its surprisingly easy to carry what most would categorize as a big scope and a big mount in a "mobile" fashion. Its not grab and go but no reason it cant be done.

Some things are prepackaged so that i dont have to set up everything every time, like for instance the imaging train never gets broken. The comacorrector and the adapters needed for backocus stay attached to the camera at all times so i can just plop that into the focuser and get going straight away. I also mark my focuser and camera with aluminium tape to get the rotational position correct to my previous setting (if imaging a multiday target) so that i can just get going quickly. Guidecam stays in the guidescope in the focus position it has so i dont really have to refocus all that much. Just a touch to account for different temperatures. From arriving to my imaging location i am set up and polar aligned within 30 minutes, which is always faster than the scope takes to cool down (well most of the time).

For trips where i intend to only do visual its a lot faster and i can drop a lot of this gear but it still gets carried in 2 trips.

The files are in the Pixinsight exclusive XISF format, mind uploading them in normal 32bit .fits format so other software users can have a go?