pipnina

Wow that really shows what a competent processing wizard can do! What denoise algorithm are you using? I have struggled to find one that doesn't make the whole image look like a jpeg artifact, even the one pix includes.

I just re-calibrated the data with the proper input pedestal and re-stacked twice. First dataset is all subs from both nights thrown into WBPP, second is only the first night's subs (so 12 subs per channel for first night only vs 45-ish for all data image). I cropped them down to 1280x1024 so this is now only a 30MB total download. I will be honest when I look at individual channels from the stack, autostretched, I can see the difference in SNR much more easily. I guess it all threw me off because it doesn't look like a 5x integration difference in SNR! All_data_correct_calibration_crop.tif First_night_only_correct_calibration_crop.tif

I did some looking through the settings: WBPP has an output pedestal which adds a certain ADU *post* calibration, and the separate ImageCalibration tool has both output *and* input pedestal. Setting the input pedestal to match my camera offset does appear to reduce the overcorrection, albeit a bit hard to see given how dark and noisy the subframe is to begin with! I stacked the blue frames that I calibrated with input pedestal and hit autostretch (right), and compared it to autostretched blue on a previous stack with no pedestal in calibration (left) Thank you very much for telling me this exists! I have been banging my head against this flats problem for what feels like forever haha.

As in normalise both stacked results with a linear fit, and register them so flicking between them in an image viwer or photoshop will let me see a flickering 1:1 comparison? It'd be worth a shot! Transparency might have been lower for night 2, but I don't know about a whole bortle lower! Might help here to see the subs: The sub with the full date stamp in the file name is the second night, the sub that's just M51_Light_Blu is from the first night. I notice putting them to the same stretch level in Kstars that the subs from night one are definitely darker, but I am not sure how much the signal in M51 is being attenuated by, it doesn't look like a 5x loss to me but my eyes are not so keen for this sort of thing. I found two of the darkest subs in the middle of each dataset and put them side-by-side at the same stretch and they look similar in terms of signal and noise, but the new dataset is definitely brighter: And looking at the stats, given my offset of 256 (which yeilds minimum ADUs around 40-60 on my cam), it seems that the average ADU value difference between the two nights is only about 80-90 ADU. It seems a bit suspicious that it would make such a big difference in the final product. As for my overcorrecting flats... I am still experimenting with the issue. I think I need to apply darks to my main data and bias frames to my flats (flats are around 0.05 to 0.01 second exposures so flatdarks maybe not so necessary?) Getting good, uncontaminated darks is quite hard though. I've burried my camera before and still seen light get in (I even stuck some socks over the front of it in a dark room once trying haha) It is a bit odd because my much noisier and stronger dark current DSLR had no issue with flat calibration, despite me never using darks or bias frames! M_51_Light_2023-04-23T23-43-01_001.fits M_51_Light_Blu_001.fits

Hm ok maybe the processing will mask it a bit I just put the two nights together into a simple LRGB combination without stretching, and the second night by itself in another simple LRGB combination I stacked the two nights combined by adding all the raw files into the WBPP script, so I avoided trying to stack two master lights (PIX refuses to stack fewer than 3 images anyhow) Maybe this makes it a little easier, I don't really see any appreciable difference myself both-night-raw.tif 2nd-night-only raw.tif

I have been trying to capture a nice and clean image of M51, and in my first session I caught an already quite nice image with only 1.5 hours in RGB. On the 23rd, night 2, I managed to bring in over 5 hours! I figured I would see a big improvement sticking the two stacks together... Alas there appears to be no improvement at all 😕 Could it simply be a matter of the second night having that much worse SNR per sub, or could it be difficulty getting multiple nights to work well with eachother in pix in general? When I stack night one and night two individually, they do look very similar, I am struggling to tell a difference SNR wise. Is it just bad luck or am I realistically limited to one night per image or per colour? Thanks Image13 is both nights together with a quick pix process (ABE, SPCC, stretch and colour boost only), The other Image13 is, as described, only data from the second night. Image13-2nd night only.tif Image13.tif

A lot of heavy technical discussion in this thread. I'm happy to enjoy the great picture myself!

My raspberry PI with astroberry runs Kstars, which is a planetarium software with an embedded astrophotography tool called Ekos. It has a lot of features and does show you things like live guidecam feed, platesolving, autofocus, image capture, goto, assisted polar alignment, mount guiding built in (or connected to PHD2) and even a scheduler which lets you set up a target, a image capture sequence and start/end times and it will automatically start capturing the target at the programmed start time. On astroberry it's quite stable but on my desktop the updates bring more and more problems- I think my desktop must have ended up running beta branches or something. I control Kstars on the PI by viewing the desktop in my web browser at my PC indoors. I set my home router to always assign the Pi's MAC address the local ip 192.168.0.33, so I type that into firefox and the Pi's desktop appears! As for board cost, how the mighty have fallen! I remember the original Rpi model B in 2012 or so cost £30 for the board, as the higher memory version. I even only paid around £80 for my RPI4 2GB with enclosure (a bad enclosure that I replaced, the metal in it acted like a wifi faraday cage haha). There is a youtube video on RPI alternatives at much lower cost, it is only a roundup but it seems in some cases we can ditch the RPI for one of the alternatives.

You are right it would be a bit redundant in your case where you'll be next to the scope- I was having a slightly confused moment where I use my RPI4 to control the scope from a distance and didn't make the connection that your and my use cases weren't quite the same haha. As for the usability: it's honestly really good. If you use Astroberry, which is a fork of the raspbian project which has a desktop, samba server, wifi hotspot and even a VNC server set up from the box, you just have to burn the Astroberry disk image to the SD card, plug it into the PI, put the power on and in a minute or so the "astroberry" wifi hotspot appears. If you connect to that you can open a web browser or a VNC viewer app, and connect to the PI's ip address and it will present you with the login screen, with some configuration of the INDI server (telescope hardware drivers) on the left. I find it very convenient and flexible, not to mention reasonably priced, but as you say the use case is limited in your situation. Also Re: availability. Yeah, I struggled to get one and settled on the 2GB model... Only to find out that I *really* needed the 4GB instead. It is a very neat setup though

I'm quite fond of my raspberry pi for scope control, but that does require a laptop or it can be a bit fiddly to control via a VNC app on a phone. You also need the 4GB pi4 at a minimum and to source a good quality 3A 5v supply and cable.

I think wind affects it more than we think. Even in winds clearoutside classes as green we can get gustsa few times in a sub that wobble things about a bit.

Given as you are using PixInsight, I am surprised Spectrophotometric colour calibration hasn't been mentioned yet! It works absolute wonders for colour rendition, even under limited signal conditions. I processed this for a friend (not my data), who uses a Moded D3200 (full spectrum). The signal is clearly limited, I think moreso than your image. Yet with PixInsight SPCC the colour looks very natural and vibrant, especially in the cigar!

That's a very good point. The only reason I suggest a DSLR in this case is because you can't beat the €160 price point on cooled astro equipment, and since the initial budget wasn't mentioned I simply went for the cheapest setup I could conceivably want to image with (and *have* imaged with). At €500 a cooled camera would be 5/6ths of the whole setup I suggested on just the camera. If their budget was €1000, maybe a 383l or something could be suggested but you need to consider the cost of adapters and power supply and the lens you intend to image with, whereas with a DSLR no such concerns exist as long as you're happy with the provided battery. low cost astro is a sticky situation but I do believe a DSLR is good enough for people who are starting, at least if budget is a concern. If they have more budget our options for kit to recommend becomes much freer for things us more experienced imagers consider essential.

I like to think of it as eventually turning into a grab & go imaging setup, and a bigger setup. If you start with the star adventurer and camera, and over 2-3 years you slowly buy the bits for a bigger setup, in the end you have your original star adventurer setup AND a big telescope setup. You can essentially work on two images at once, or only take the kit you feel like setting up with you on any given excursion. I just feel like waiting to get the perfect setup for 3 years might just be needlessly prolonging things on a hobby you'll have spent thousands on but never participated in until those 3 years are up! If you buy something for €500 and enjoyed it for 3 years, did you waste your money or did you invest in a good time? That's up to you. There's also resale value to consider if you do only want one setup in the future.

I think it could be a good idea to start small first, then as you say work up. If you got the initial kit as described you can get going quickly, get several hours of images without needing a laptop or big battery bank (camera and star adventurer run off internal batteries, my SA's AAs lasted for about a year) and once you start upgrading, like you say you can do things like pick up that battery tank and a HEQ5 (maybe stretch to an EQ6-R as it's a good jump up for the price), then replace the camera lens with a telescope, then later again replace the camera with a cooled astrocam. I think spending several years buying parts that you can't use maybe doesn't make the most sense, but if you get a cheap setup and then slowly replace bits in the right order you'll end up in the same place, but will have been imaging for 2 years instead of collecting cardboard boxes! Hopefully this makes sense and I'm not waffling haha

I second this: Only consideration is that it does not include lens. 160 euro + cost of lens + (in my opinion) skywatcher star adventurer and tripod would be a bit over 600 euros total @Balthazar Saissore Can I ask again if you have a particular budget in mind to get your total equipment setup?

I think to a certain extent, when starting out, the best AP equipment is the stuff you already have! I've taken passable astro photos (as well as others here) on my Google Pixel 6 phone! It takes more effort but you will always run up against the cost vs performance paradox. If you could outline the rough total amount of money you would want to spend on the whole setup, it would be easy to work out a few (relatively) inexpensive options for you! If we say 600 euros is your total, you might look at something like a mk1 star adventurer, plus a tripod (I use a manfrotto 055, but that is a bit pricy, as long as you get something rigid it should be ok!), you will by this point probably need to settle for a DSLR + kit lens. I see skywatcher sells a tripod specifically for the SA now, both the SA kit and tripod together come to about £430 (not sure how much for in europe). This would leave about £170 for the camera and lens, a bit of a squeeze! You could potentially get a canon 1200d for this however... Relatively modern DSLR with an ok kit lens. Certainly a setup like that can do fairly well, given some processing and a fair bit of exposure time. I captured this years ago on a Nikon D3200 on a star adventurer, but i forget how much exposure time: This was before any processing, at the widest fov I think (18mm). Don't ask me about the framing, I don't remember taking the shot! haha. You can see orion clearly and there's some flame nebula... maybe a bit of horsy shining through as well? I re-processed it when I bought PixInsight and the hidden details it brought out of this super-cheap setup (My D3200 was also unmodified and second hand) was stunning. I think some people can achieve similar processing results with free tools like siril but I have never tried it. In this process of the same image, suddenly we see milky way dust lanes, much more pronounced nebulae in orion, maybe a bit of barnard's loop? (!) and the rosette appears as well. You might outgrow this kit lens fast, but once you have your feet on the ground with this you can switch it out for something like a 100mm-ish lens that runs faster. I captured this on the same setup, but replacing my 18-55mm kit lens with a sigma 105mm f2.8 macro: Again this is a reprocess in pixinsight, but it's original data from a Nikon D3200, star adventurer on a tripod and a lens I bought a year or so after getting the star adventurer. At this time my camera was NOT astro modified! So all that hydrogen is in spite of the filter being in place. I did modify my D3200 eventually... However despite it initially being a success I did manage to disrupt the camera, it really is quite fiddly to get one of these things apart AND back together again! After modifying I did get some very nice looking nebulae, but the camera developed a bit of a banding effect (you can see two wide darkening lines going horizontally). If you decide to mod the camera, do so if you know you can afford to replace or upgrade if it goes wrong! I hope this helps inspire some confidence, as it is very challenging to get into AP on a sub £1k budget, but I think even a basic setup as described will get you hooked, and there is a lot of room to improve even on just the star adventurer mount (mostly via lens upgrades). good luck and have fun!

That sounds like a great idea! Keen to learn how you get on, the phone's sensitivity to HA makes narrowband a tempting prospect.

I bought a UHC and an OIII visual filter in november, and I havent used either yet! I was hoping to observe M42, flame and horsy with them but never got the chance... Oh well, next stop: NGC 7000 I think.

The laser AF could possibly also be tacked or taped over maybe? Given your sky colour, a typical LP filter might not help that much, especially with broadband targets. Also consider giving DeepSkyCamera app a looking when doing more fancy things like adding filters, as I believe that app does allow you to se the manual focus point, and in the future (they say in a paid version) it will control the telephoto camera too!

I also only have a Pixel 6 (the middle tier one that doesn't have a telephoto lens) and I did try the AP mode by itself, once using the RAW + AP mode built into the phone, plus stacking some of those together with PixInsight. Another I made with DeepSkyCamera app and pix stacking. Here are my results: Sadly I found the camera to be severely lacking, mostly in the optical department but the sensor was a bit hit-and-miss too. The two big things optically are distortion (it seems to ripple in waves from the center, no distortion and sharp image gives way to STRONG coma, a few times), and very intense vignetting. I was unfortunately unable to use flats to get rid of it and so had to rely on teasing the background extraction tools in Pix. The big thing sensor wise is dark current. The sensor was more hot pixel than not, requiring dithering. But as you can see from the images above (Cassiopeia image was dithered, Cygnus was not) dithering does make the distortion much more pronounced in the final image. I think the way forward with the P6 is to take raw images using the 4 minute AP mode and stack them, as the P6 will automatically remove hot pixels with its own stacking process. Taping an ice pack to the screen side of the phone and controlling it remotely with developer controls might help too haha. Would I buy this phone for the AP capacity? I don't think so. But if I were considering it regardless, I think its capabilities are surprising! Not least that it picked up the hydrogen in cygnus from NAN to SADR. The eagle-eyed may even spot the veil nebula and the heart & soul neb. This is what PixInsight rejected from the Cassiopeia pic during stacking (stretched):

With such a massive range of flatteners about, it's hard to say which ones, or at which price ranges, are any good. I certainly found that the TS Photoline 0.79 I used with my APO was not very good (chroma, undercorrection etc). Not knowing how much I might need to spend, I decided to go for a "cheaper" option on FLO first: The Starfield comes in at only £220 which is quite low-end for big-scope flatteners (WO sell one at £700+, the small Riccardi sets you back nearly £500). But it also comes with the benefit of a big set of lenses and rare feature of adjuatable backspacing! I got my old kit off the back of my scope, assembled the focuser with the new corrector, and a WO rotator I picked up to allow me to continue adjusting the camera rotation. Immediately I found that this corrector moves the focal plane a lot more than the Photoline. So much so that even though the corrector sits in a similar place to the Photoline, my focuser ran out of travel! I had to remove the rotator to give me enough slack, and I only have a few mm left either way. Impressions once I got my focuser re-straightened for the new kit were quite good. Stars seem quite tight around the field, with a small bit of coma right at the corner of my APS-C frame, however this may be related to backspacing which also needs some discussion. I started off with it at 0 on the adjustable scale. I noticed it might be a little short so I moved it, in two goes, about 5mm further out. Surprisingly this had little affect on the image! My Photoline flattener was so intolerant of backspacing error that missing 5mm of backspacing produced a warp-speed effect! This one almost doesn't seem to care, but I will need some more testing to be sure. As for a more "final result" here's a stack and a single-frame (3-sub R-G-B) colour image of the results: I think the biggest issues with the corner stars here come from the optics of my OTA and not the corrector, I think my focuser is still slightly mis-aligned or maybe my front cell now isn't 100% tilted properly because the focuser has moved. Either way I think this is a big improvement over the photoline in various ways (less vignetting and nowhere near as much chroma spread at the corners for one, better tolerance for poorly set backspace for another. And the price is quite reasonable. This is on an APS-C sensor. Photo taken with the Photoline for comparison:

Signed! I was very disappointed a few months ago, when the fire station on the street below me finished its renovations. While the building is far better for the fire service and looks nicer as well: The builders have installed the outdoor lights neigh on pointing upwards! There's one floodlight that is so bright and poorly angled, that I (50 meters away at least) could use its light to read by in my kitchen when it's on. Ludicrous! It literally lights up the side of the house, not nice...

I thought I was having it bad with no imaging from dec to february! You've gone very deep in the limited time you had at least!