ONIKKINEN

The simplest is to use the script and peer into the "Process" folder that the script creates in your working folder and grab the calibrated files from there (assuming its the default scripts you have used here). You will find a bunch of files with the prefix "pp_lights" which are your calibrated lights, the files are also debayered in case you ran the OSC script for colour data. You can then just drop these into some other folder where you might keep work-in-progress type data for later use in case you want to keep adding data. Then just drag and drop all the different files from all the different sessions to the Conversion tab window, or you could use the "+" icon to add them there. Name the sequence and click convert, it will create a new sequence from all the data you fed it. I recommend setting the Symbolic links option on as this way Siril does not actually write any new files and the sequence is imported basically instantly, instead of writing several gigabytes of files first. If you have more than 2048 files it gets a bit more complicated because of OS limitations but im assuming not, so wont get into that now. The less simple - at first - way is to create your own script that does whatever you want it to, such as just calibrate the data. The laziest method is to find the script in the Siril installation folder and edit the premade scripts to just calibrate the data and stop there. The files are in .ssf format but WordPad will open and work with this format just fine, the edited file has to be saved as .ssf after the edits. Simply remove the parts i have crossed below and the script will now save non-debayered files and not register or stack them. If you want to have the files be debayered at this phase then dont remove that part. If you save the files as not debayered you also have the option to use the "seqsplit_cfa" command to split debayer the OSC images. This creates 4 mono images from each raw input sub: 1 red, 1 blue, and 2 separate green ones. The image size is also effectively binned x2 this way. * Edit Realized that i did not really answer the question of how to stack manually, but its fairly simple. After the sequence is created you need to register the files through the Registration tab. Use Global Star Alignment with Lanczos-4 and Interpolation clamping option enabled (make sure you have the newest version of Siril). For RGB data its probably best to have the channel set to green as thats where the best SNR is likely to be found. After registration completes Siril will then draw a plot of various statistics into the Plot tab where you can remove images with bad FWHM, low star number, bad roundess, etc. Handy tool really, at least give it a small look before stacking everything as you will learn how good the data actually was. For Stacking, you can mostly stick with the defaults, at least i think these are defaults: Average with rejection, Normalisation as Additive with scaling, winsorized sigma clipping with 3 for high and low range for the Pixel Rejection part. If you have a lot of dubious data of various quality skies then be sure to use some kind of weighting for the subs, such as #stars or noise or whatever. If you want to get a tiny little bit better pixel rejection with less actual faint signal removed then use the Generalized Extreme Studentized Deviate Test method. It consistently clips fewer pixels so presumably clips less faint stuff, but gets rid of all outliers. It takes much longer though, like several times longer.

Very pleasing image to look at as it has a bit of everything, plenty of stars, dark nebula, reflection nebula, emission nebula. Really nicely processed too, everything looks very nice.

Ill add to the discussion that the exposure times required to have read noise dealt with are likely quite long for the f/10 scope so the mount needs to behave probably for 5-10 minutes in normal operation. Vlaiv has made good points and suggestions, other than M31, M33, and some galaxy clusters such as the Virgo and Coma clusters you will fit every galaxy in a 2m fl scope and an APS-C chip. That leaves you with dozens of good targets and hundreds of difficult ones.

Does your Omegon 150 have a 1.25" focuser? If so it will be difficult to find a coma corrector (not sure one exists on the market) that is more or less required to have good sharpness in the images for wider fields of view such as with DSLRs. I would suggest not pouring too much money on this particular setup for astrophotography, but buying something that can get you started for a not so obscene amount of money while still sticking with the scope for now. Idea: get a simple tracking motor and a planetary type camera that works better with the small focuser. You can take nice images of the Moon, planets and some of the brightest DSOs that fit the field of view. If one day you upgrade to a different setup you can keep using the same camera as an autoguider or a lunar/planetary camera so you waste a little money as possible. Be warned though that astrophotography twists your idea of "expensive" into really deranged numbers if you get hooked. No upper limit in spending, but most dedicated imagers will end up spending several thousand €/$/£ really quickly...

Siril will stack your different pixel scales together just fine in "normal" operation, choose one reference frame from either setup and stack everything to that (doesn't matter which filter, just choose one with a lot of stars). No need to do pixel math for the resolution matching or something like that although you may want to do that for the RGB composition phase if you are adding Ha to R or something similar. Dont know where the limit for scale difference is but i have stacked 1.8'' and 1.5''/p frames together and it all integrated just fine.

Looks like another miss (mostly) for northern astronomers, its under the horizon or daytime at the closest pass. Late october might work ok if it stays intact after the periapsis pass and the brightness estimates are to be believed.

Go-to inaccuracy and difference in image orientation pre and post meridian flip come to mind as potential issues. The first is of no concern to any imager who uses plateolving, the initial go-to will be inaccurate anyway so nothing lost here (except maybe the 10 seconds spent on the first slew). The second, change in image orientation, increases in effect the higher you point in declination and could well be an issue if you are shooting a mosaic with tight tolerances or a target that generally just barely fits the FOV at some specific camera angle. I have had fairly significant cone error (and still have) and have seen up to 3 degrees of difference after a meridian flip when shooting M81. Not an issue for my FOV but could be for some kit. For targets at lower declinations its of no concern at all.

Darks care about exposure length, temperature, gain, and offset. The telescope or whether there even is one attached to the camera does not matter for darks so they will work in any camera orientation. Flats do require retaking each time you remove the camera or change the orientation.

Beautiful image all around, rich background, extensive tidal streams and of course the galaxy itself. On StarX removing background galaxies, you could add them back to the starless layer from the stars only layer. Takes a bit of manual work with the eraser to remove the objects not wanted in the star layer. Then just subtract that layer from the original star layer and you're left with a layer that contains only the background galaxies. Now you can do with them as you please or add them to the starless layer for some extra work. Easy to do in PS, just takes a while with a background as rich as this! Actually you could do it the other way round too, removing all the objects that are actual milky way stars and then do the layer shuffle. Might be easier in very rich background images.

Actually since you mentioned wildlife i remembered the most dangerous part of darksite visits here: the drive. Have seen deer on the road countless times and have had to brake suddenly a few times.

Never felt unsafe at dark sites so far. Mildly annoyed maybe if some youths on a mid 2000s BMW with a DIY bodykit start drifting and making donuts nearby and generally causing a scene (you know exactly the kind of guy im talking here im sure...) but never felt actually in danger. Most people dont approach even though they look curiously what im doing (Finnish thing) and those that do are always nice encounters. Your mileage may wary of course but personally am not worried.

The porkkalanniemi carpark marked in the Ursa observing locations map. There were 5 cars at one point all imaging/observing, its become more popular as of late but plenty of room anyway.

Never heard of this one, added to my ever growing list of things to image 👍. Interesting looking galaxy, all kinds of messed up and a lot of different types of signal to be captured in spiral arms, H2 regions etc. I think the aversion to small and faint targets is somewhat easily explained by the typical weather a typical imager posting here on SGL experiences which greatly demotivates most of them from dumping dozens of hours on a target that may or may not be worth it in the end.

Previously i have been very happy with my Ecoflow River 300 (discontinued model) and would have recommended one or one like it. But last night it failed on me after about 7 hours. I checked the power level at around 1am and it was around 40% which was plenty for the 2-3 hours i was planning to stay for longer. At around 02:30 it had shut off and claimed 0% charge + low temperature discharge warning so it must have drained a lot of power in the final moments. Reading online the longevity of the River 300 was a big issue and probably why it was discontinued. Also probably why mine failed last night at -15 when i have used it for a similar amount of time in -25. Newer models may be better, at least would hope so. Newer models of the river advertise down to -10 discharge temperature where as mine is -20. Maybe they just realized -20 is too much and it kills the battery and so just changed it. Its still been a good purchase but after 2 years of mostly sub zero use its starting to show cracks. Maybe i shouldnt complain actually given its been kind of tortured for so long.

Was also imaging last night and saw this show from a latitude of 60N. That naked eye red light was really something else, you have captured the sensation of seeing the sky on fire nicely here.

Just arrived back home from an imaging trip, not in the UK mind you, but we had the same Aurora but i would imagine a bit stronger as i am at 60N. These were by far the strongest i have ever seen, i could see these vibrant green curtains dance in real time across enormous swathes of the sky including at the zenith and south! Occasionally some pillars of green light appeared as if out of nowhere and disappeared, as if there was some kind of celestial bombardment of light. I now understand where all the mythology of getting smitten or struck by something from the sky comes from! We had naked eye very obviously red Aurora too, which is a first as well. Typically only seen that through a camera, but this time it was like the sky was on fire. Funnily enough it ended up ruining a bunch of subs i was taking, but this type of ruining of the images is acceptable i suppose. Aurora gradient, hah, take that light pollution gradients! Some crummy out of focus shots with a shaking hand and a phone (was actually rather difficult to image, as the direction of the lightshow was everywhere, and i was busy trying to pick the pieces of my jaw off the ground):

Had a look at the Moon with the 90mm sort of achromat Long Perng. Seeing not great but very nice views with a 2.5x barlow + XW7 giving a nice power of 178x which the scope wont go above in any seeing. Or so i thought, but trying with the new narrower Baader solar continuum filter im seeing a crazy increase in clarity, its like seeing was suddenly an arcsecond better and most of the high frequency fuzz is gone! This time i could definitely use more power, but alas i have run out of glass for that. Recommend others give it a try, it really improved the views a lot with mine.

Look up ASTAP platesolving, its what you are after. The H18 database is like a gigabyte, not a terabyte and i dont recall platesolving ever taking more than a couple of seconds (ignoring a few user error type situations...).

Lovely, i really like the diffraction spikes. Adds character to the stars that is sometimes missing from RASA images where the stars are very much a secondary part of the image compared to the not-stars part.

Its back up and updated to 1.2.0-beta1: https://siril.org/download/2023-02-24-siril-1.2.0-beta1/ Looks like an enormous update to Siril. Added features include, at least: Binning, clamping for lanczos-4 interpolation (no more dark star artifacts), starnet integration for separate star and starless processing, reworked deconvolution and PSF measurements and im sure much more. The price to performance ratio of Siril just keeps on getting better!

The EQM35 is an EQ3 in disguise, it has no bearings on either of the axis and so is pretty much unservivable junk that will not work properly. Both of the axis are supported by plastic shims and lubricant and thats it, backlash and wobble a plenty! The EQ5 actually does have bearings and is generally much more robustly made and so shouldnt be compared to the EQ3 and 35. Also very similar price and weight to the EQM35, so there are hardly any reasons to get the 35 instead of the 5. On the Exos, sorry, cant say as dont know too much about it. Used to have an EQM35 and can safely say its not the mount you are looking for, nothing but regret in my mind as i think about that purchase.

Why not the EQ5? Cant say about the Exos-2 but you definitely dont want the EQM35.

How big of an issue is a satellite strike for professional astronomy really? Is it only a critical issue when the satellite happens to fly directly over some tiny target that just so happens to need that exact moment of clarity, like i dont know, exoplanet transits or something like this? Genuinely dont know if its such a big deal. But the speed of development is the worrying part here for sure. 10 years ago mass launching and more importantly: mass launching and re usability at a low cost was not on anyone's mind and now its just another day in the industry. Where are we 10 years from now? Kessler syndrome will happen, the question is when and i think its not too many decades off if more private entities want to get a piece of the orbiting internet money generator pie. Also what worries me is that why is this necessary and is it really such a good long term investment? Fiber optic internet is faster than satellite internet simply because the distances are shorter across the ground than first doing a hop to 600km upwards (the wrong way) and then several similar hops of the signal between satellites, at least the speed thing is valid for more or less local connections (like within europe lets say). Most urban areas in the developed world already have good fiber and that doesn't fall out of the sky every 7 years. Areas around the world that are still developing will want to get fiber infrastructure rather than a private internet owned by the richest person in the world that can be switched off or reduced in capacity at will...

Clipping will remove the trails from images so not really worried about that. From a kessler syndrome point of view, maybe a bit worrying but its only a matter of time that becomes a reality anyway.

Depends on the location i am shooting from but i try not to image under 40 degrees due to seeing and light pollution getting pretty bad there in most of the locations i visit for imaging. In the case when a target starts at a low altitude but gets higher during the night i will start with another target that is higher in the sky and switch over to the primary target once its high enough. This way i always try to get the most optimal quality data possible from every night out with the scope as clear skies are so rare i really dont want to use the precious time poorly. Of course some targets do not rise that high and they need to be imaged at as low as 20 degrees and in this case i try to travel to a location that has the best possible southern low sky since light pollution is multiplied greatly by the low elevation. For different sub lenghts, i dont pay it much attention. I shoot either 1, 2 or 4 minute exposures depending on how dark the skies are, filter used, and if its windy or not. I already know what ADU numbers to expect in the background for read noise to be swamped x3 (the minimum i aim for even if windy) so i just use 1,2 or 4 minutes based on that. Differing background levels between different nights or during the same night are of little concern because normalization will take care of that in the end. But i do try to not mix awful data and great data for the same stack as the bad data could lower the SNR in the end. For example i will probably not bother shooting a target during a full moon if i already have 3 nights from a borle 4 sky without a Moon.