13. Live Stack with the ASIAir Pro

earlier this week I went out to photograph the Lagoon Nebula with my dedicated Astro camera and narrow band filters there was one difference though this time and that is we're almost to the full moon so there's a lot of moon light out and that caused some unique challenges but also some unexpected benefits in this video it's gonna be more laid-back I'm just gonna walk through what I did here in the asar prolapse so for those of you who got one or thinking about getting one this might be a good look at the application and how everything works I'm also going to discuss some of the problems I encountered that way you don't make the same mistakes I did and then the end of the video we'll see how the final image turned out of course the first thing I did was my polar alignment and this was actually very easy with the moon being out because it washed out all the fainter stars as soon as I looked through the polar scope I could see a big bright star which was obviously Polaris so I got my polar alignment within probably two minutes or less really precise then I started up the SAR Pro and began focusing my space cat telescope with a baton off mask that way I could do an even more precise polar alignment here in the application however this brings me to the first and most important mistake I made all night I did not focus my hydrogen alpha oxygen or sulfur filters so just to be clear here as you swap your filters it's gonna change the focal point of your telescope so you might have a perfectly focused here with the L filter but if you swap over to hydrogen alpha the stars may no longer be sharp and that's the problem I encountered the other thing that goes along with this is that when I was trying to find the Lagoon Nebula there were no big bright stars to focus on like you see here that meant the badnote mask was pretty much useless and I just had a heck of a time getting everything sharp with my narrow band filters so looking ahead when I try this again on another night I'm going to swap over from the L fill true to my hydrogen alpha or myself or one of those and make sure I get the focus precise there if I know I'm gonna be doing narrowband that would make a lot of sense because again once you find your object there might not be any bright stars over in that region to focus on once i had focused Maya tell escape I was ready to do my precise polar alignment here in the asar pro app and this is one of the great things is that if you're not quite sure if you did the visual alignment correctly you can always use the to double-check so you click preview in gold then you could choose PA from the list over on the right at this point what's going to happen is that provide your telescope is pointed up to the North celestial pole then it's going to take a photo analyze the Stars that it sees and figure out where it's actually pointing then it wants you to take a second photo so you loosen your clutch move the camera and everything down almost like you're balancing the counterweight lock it into place and then you take another photo it analyzes the scene looks for the stars finally it's going to compare those two images and see how things have rotated and really nicely it's going to show you to move up down left or right on your base to get a precise polar alignment and as you can see there my total error was only six arc minutes usually that's why I trying to get down to using the application so the fact that I got my polar alignment so accurate with just the visual polar scope and the sky Gadar pro was a good sign because I've always struggled with this in the past but lately I'm really starting to get the hang of doing a visual polar alignment and to be honest normally I tell people just to leave it be if you get within ten arc minutes that's usually good enough polar alignment for what we're doing unless you're shooting above 600 millimetres so honestly I mean as you're gonna see here in a second my polar ulema is really good then I tried to get it a little bit better and I made things way worse that's very typical when you adjust anything when you're that close more often than not you're gonna overdo it and you could spend 10 minutes just trying to get it a little bit better so like I said normally if hiking it down to five or six arc minutes of total air I'm happy with it but in this case I figured might as well just go for it and after a couple of attempts I finally got it down to I think it was like one arc minute and then z wo rather the application was happy and it let me stop and one of the cool things about this application is that actually ranks your total time to get a good polar alignment which you see right there and I remember I was teaching a deep space workshop back in November and one of the students actually got a really high ranking and this was all I guess third time doing a polar alignment so that's always fun to see if you do a really good job in a short amount of time once I'd completed my precise polar alignment my next goal was to find the object that I wanted to photograph in this case the Lagoon Nebula normally this would be very simple because it's in the core of the Milky Way it's fairly bright and it's not that hard to find however the problem I had is that that moonlight from the nearly full moon was washing out all the brighter stars and the nebula and the Milky Way itself so what I decided to do was use an app called Stellarium on my smartphone so I zoomed in the Lagoon Nebula just give you an idea of what we're looking at here right in the core the Milky Way and then one of the cool things here in the app is that you can change the milky way brightness I wanted to match what I've seen with my naked eye that way things would be a little bit more easy so down here was his milky way brightness I just turned it down and that's realistically about what it looked like to the neck high on the night and even that's a bit bright then what I decided to do was look for those bright clusters of stars like we haven't Aries over on the right and I was just correlating what I saw in the app with what I was able to see with my naked hi and use those bright stars to help align to the Lagoon Nebula and I ended up using this star right here it's kind of my guide star so I was able to see that one with my naked eye along with all those other ones and I knew okay if this is where I'm looking at I need to go over to the right and up a little bit and the Lagoon Nebula will be right there at this point I turn on my laser pointer which was rubber-banded around my telescope and I moved that around until I was right where I thought that Lagoon Nebula would be and I took a photo here in the application I remember the first time I did this I thought I'd captured amazing comet or something then I realized just it was just the laser pointer in the frame but it makes for a cool photo even just doing that so at this point really all you have to do is just keep referring back to stellarium for those stars looking up with your naked eye and using the laser pointing to get as close as you think you can to where the object should be and sometimes it actually helps to put on the hydrogen alpha filter when you're photographing nebulae because it'll really stand out like a sore thumb the image will be a lot darker and grainy err but if you have the nebula in there in most cases it'll really show up with the HL filter and for those of you who have the go-to mounts you're saving yourself a lot of time and headache you just type in nebula and it'll go right to it you can even do that here in the application if you have sky Safari those all work together with your go to mount if it's compatible once I finally get a go to mount I will do some videos on that because I think it's really cool but as of right now I'm just still using the sky gunner Pro as you see here after a decent amount of time I found the Lagoon Nebula using the owl filter and just to make sure that was correct I swapped over to the hydrogen-alpha filter and I got an even better look at the nebula now once you get the object somewhere in the frame obviously your next school is to get it centered up so that's where you're gonna adjust your right Ascension and declination access on your sky guide or pro and between those two access you'll get the object towards the center this can be more difficult than it needs to be often but with a little bit of work you'll get it right where it needs to be and in my case I accidentally moved my whole right ascension access when I was trying to I think put on the batten off mask so everything jumped in the frame that tends to happen quite a bit just because I clutch for whatever reason doesn't seem to completely lock down my sky got a pro so in this case I had to spend even more time getting it back to the center and then as I set up on the bad nut mask so trying to refocus with the hydrogen-alpha filter because every time you swap filters you do want to double-check the focus but you're starting to see how as people have mentioned if you had a go to mount and everything maybe one of those electronic focusers it would make your night theoretically a lot simpler just because it's handling a lot of his manual stuff that you can waste a lot of time doing and here if we zoom in this is with the baton of masks on but you don't see that iconic star pattern because the stars are not bright enough this is what I was getting at earlier in the video where I should have done this when I was pointed up at the North Star which was a really bright object that way I could have ensured it was focused before I moved over another problem I had is that I was running out of time I woke up at about 2:45 took me about 30 to 45 minutes to get everything set up and ready to go at this stage and I'd only left me with about an hour to capture my hydrogen alphas sulfur and photos not really a lot of time so eventually I said you know what I got the focus as close as I can get I can't waste any more time I need to start imaging and that's why I eventually just kind of gave up took off the bat not mask and started imaging and I think right about here is about as sharp as I can get it like I said if I could go back in time I would have pre focused on the North Star that would save me a lot of time and headache and then once I found the object I'd be ready to go once you've got your objects centered up and you're ready to start taking your photos the last thing we always want to do is start our guiding software that way our star tracker runs a lot more accurately and in this case I ran into another problem my guide scope wasn't completely focused I mean I probably could have left it where you see right there but I wanted to make sure it really was on the money so I tried to refocus my guide scope and this ended up wasting about another five minutes of my night because I didn't know which direction to turn it it made the Stars look worse then I'd go back I just kept doing this back and forth for like I said about five minutes eventually I said good enough and then I was ready to begin my kiting and that allows me to get anywhere from two to three to four times longer exposures without star trails on my sky guide or pro it really is remarkable how well the guiding works so for those of you who don't have an auto guider yet it really is recommended to be doing any kind of deep space work for those of you who have used PhD 2 on your laptop the asar guiding software is almost exactly the same you connect your equipment in the app you begin looping you click on any star you want and then you click the begin guiding button which is that grayed out little crosshair icon on the right at that point it's gonna do a calibration and this is why you always want to save your auto guiding for the very last step because it's gonna calibrate to exactly where you're focusing on in the night sky and as you can see it goes like west step 1 2 3 4 usually up to 12 15 or 20 then when it's gone far enough west so it'll go back to the east this is only if you have the sky cutter Pro the started venture that we can only do our guiding with our right ascension access if you had a go to mount this would take even more time because it can also guide your declination access so for most of us using a star tracker this shouldn't take more than a minute or two those yellow lines if everything worked properly will turn green once it goes down the east step zero and at that point the auto guider will send commands to your star tracker and try and keep that star centered up in the little box in our case if you do have a sky guide a protostar adventure essentially all it's doing is telling the star tracker to speed up or slow down very briefly to Eve that star centered up since we don't have a declination access we can't control it so it tends to drift off on its own depending on how accurate your polar alignment was and if you're completely new to Auto guiding you need to understand this graph here where it has zero four and eight seconds there's also minus 4 and minus eight seconds those are arc seconds they're used to measure accuracy at night and it's really going to depend on the pixel size of your camera and the focal length of your lens or telescope that you're using the smaller your pixels and the larger your focal length the more accurate your Guiding has to be pretty obvious there's a whole equation you can do I've got an article on my website I'll probably pop up for that if you want to learn more about that but it's really important to understand what's going on there the very last step I had to do before I could begin taking my series of images was find my maximum shutter speed without star trails and in this case I tried for a three minute long exposure because there was no real wind out there my polar alignment was very accurate and the guiding seemed to be working well so I figured it a 500 millimeter focal length equivalent with my sky gutter Pro everything was well balanced I should have no trouble shooting three minutes but I had to verify that rather than wasting time although you could argue it was a waste of time to sit here and test it especially given the fact that I was running low on time anyway I let it run and then once it completed I checked the preview zoomed in and made sure everything looked good and rather than use the typical autorun feature I wanted to try the live stacking option here in the asar Pro this is something I haven't done before I've only read a little bit about it and I figured I'd give it a try so the first thing you want to do is select your shutter speed in my case three minutes then you can specify for taking lights flats darks or bias and it's really important here that you say leave all frames when stacking in case something goes wrong you can still do things the old-fashioned way if you check that box and one of the weird things about live stacking that I thought is that you know with our typical workflow we take our light frames first and then at the end of our imaging session we take our dark frames and our bias frames and maybe our flat frames as well and then we throw that into our stacking software in deep sky stack or whatever we're using and it calibrates all those frames one side note here I also turned on my cooling I wanted to make sure I did that before I started my final imaging session and there was no point turning on beforehand because I wasn't doing anything important but now that I'm taking my photos for real if I turn on that cooler it's gonna help to reduce some of the noise and you look at the bottom of the frame there it says it goes temp 11 degrees Celsius and I waited until it got all the way down to minus 10 getting back to the live stacking though what I was getting at is that when you live stack you actually have to do things in Reverse you have to take your darks flats and bias before you can take your light frames I thought that was kind of weird after messing around with the app a little bit more I realized there's an alternative way to do things so in the center of the screen you see flat dark and bias if you click on one of those it allow you to go into the flash drives memory and find some previous dark frames or BIOS frames or flats that you've already taken in this case I can click on my first dark frame and select it I would have thought you could select more than one but for some reason you can only select a single dark frame then you can check the box to apply that to your live stack and you can repeat that process with the bias frames if you want to do that however for the bias frames you have to make sure mainly that the game stays the same so you have to use the same gain from night tonight in order for the bias frames to be effective if you took your bias frames of the completely different gain this will not work and for your dark frames you have to have the exact same exposure the same gain and the same sensor temperature if any of those three things aren't the same from when you took your dark frames till when you're taking your life frames now they will not be subtracted properly and it'll actually more problems than they solve but at least here in the asar Pro app it's gonna show you how long this whole thing's and it takes to complete and you can also change the amount of flat frames that you want to integrate so you can do five ten to fifteen or twenty and if they were five seconds long each one of your flat frames that would take twenty five seconds in this case same thing with dark frames however with my dark frames those need to be the same exact shutter speed as my normal life frames in this case one hundred and eighty seconds and you don't want to take five or ten dark frames that's not really gonna work that well usually according to my research you want a minimum of fifteen if not twenty dark frames for the best results and therefore if I was doing 180 seconds I think if you did the math it would take me an hour just to get all my dark frames and I don't have time to do all that I need to be capturing light frames so that's one of the problems I have with his live stacking thing is that it wants you to do all this stuff before you can take your light frames therefore rather than waking up to 45 in the morning I would have had to wake up at like 1:00 in the morning or just pull an all-nighter that way I can take my flats darks and bias ahead of time and then finally I can be in capturing my life frames so for me personally in my shooting scenario I don't understand live stacking for me it doesn't make sense because I'm all about capturing my light frames immediately and then worrying about darks and biases if I want to do those and as I showed you earlier you could always apply your flats darks and bias that you took from another night if the camera settings you're using then and now match but it looks like you'd only use one at a time so I still need to do more research before I can save that works well or not and thankfully I did click that checkbox for save all frames and when stacking otherwise as you'll see here I would've wasted the whole night because it turns out I think I did some stuff wrong here with the live stacking so once you have everything ready to go then you pretty much just click that circular button over on the right it's going to start taking in this case three minute long exposures with my hydrogen alpha filter and you can let it run as long as you want the more photo is the better and ideally like I mentioned you would have already taken your darks and flats and biased that way could calibrate each frame it's taken and stack it here in the application that way you don't have to do this later and deep-sky stacker whatever you want to use and this is always my favorite part about treating with a hydrogen-alpha filter is that when that first photo finally completes it's amazing what you can capture you'd never be able to get anything like that with anything else so it is a lot of fun when you're photographing these nebulae to use those narrow band filters and just capture all that incredible detail but otherwise is usually pretty hard to capture effectively once I had captured seven images with a hydrogen off a filter now I need to stop the live stack and move over to one of my other narrow band filters in this case I clicked up on my little filter wheel button and went to my oxygen filter that way I could be in a live stack with that filter on and do another seven images this is where I made my critical mistake though in that I did not save the final stacked image I thought it was going to be just save automatically to the flash drive however you need to make sure that before you start a new imaging sequence you click the download button there in the lower right with the downward arrow if you forget to click that download button after your first series of images you will no longer have this final stacked photo you'll only have the individual frames if you check that box right there which I told you to earlier in the video and I didn't realize this at the time so I really shot myself in the foot then when I did in this case I swapped over the oxygen filter already I click the circular button and I hit restart that way I could stack all my oxygen images separately just like we would do in deep sky stager or anything else but when I click restart it just killed that completely stacked photo that we'd been working on so I pretty much wasted my time in some sense so my whole point here is that you've got to make sure you click that download button otherwise you won't have the live stacked photo saved to your flash drive on your ASI air and I even went in here to the folder structure to see if that was accurate and that's when I realized that all I had were the seven individual frames not the final stacked and that's why I was I must have forgotten something so if nothing else hopefully you don't make that mistake as well another thing you want to pay attention to is the fact that it says whirpool I misspelled will pull a couple nights ago but what I'm getting at here is that when you use the live stacking feature there's no way to name the series of photos that you're taking in terms of the object so if you're going to be doing live stacking go to the autorun feature anyway and change that from whatever it was before to what you're photographing tonight that way the naming structure lines up properly so in other words the live view is just going to refer to whatever you had set as your object name in the auto run sub menu all right so let's over the laptop now I'll take a look at what I actually captured and then I think we'll call it a day so we have the Lagoon Nebula folder here my light frames and thankfully I checked that box when I was doing the live stacking that way I actually had the individual frames if I would have checked that box all I would have had is a single stack of sulfur images because that's the only time I remembered to click the download button like I showed you so at least I have this we can compare to if we head over to deep sky stacker you'll actually see what I'm talking about here is a single 180 second exposure with a sulphur filter if I adjust things you can kind of see what's going on really not that much detail with that filter now if I swap over to the stacked version with seven software images we have this so that's what the asar pro did in the application that's ideally what you would have had if you did everything correctly as I mentioned though I really screwed things up and I had to do things manually on my own the way I did that is I went to open picture files and I just grabbed my seven hydrogen-alpha frames and these actually turned out really well I mean I think that looks awesome just I love doing H Office stuff but once I had my seven hydrogen-alpha frames I also took my darks and my bias and I took these at the end of the night during Twilight because I couldn't shoot anymore anyway that's the perfect time to do my dark and bias frames rather than before like I said I don't really understand live stacking because why would I waste my time taking darks and bias when I could be capturing data so again there might be something overlooking but for me live stacking doesn't make sense for my shooting scenario there's the darks I also dig 100 bias during Twilight had everything covered up and there we go now you should know to use deep sky stacker I've covered this in some of the other videos so I hit stack check pictures I had about 21 minutes of data for each of my three narrow band filters once I stack them all together separately and I had sulfur oxygen and hydrogen alpha final Tiff's let's take a look at these closer and then we'll call it a day after that so I'm just gonna stretch these out very quickly until we can see that data and you've probably already noticed thing one the problems I made I mean it's pretty obvious but let's give it a stretch first okay so we have sulfur oxygen hydrogen alpha I did hydrogen alpha first then oxygen then softer in terms of the imaging sequencing so what I'm gonna do is put these all in the same workspace that way we can really see what's going on all right look how blurry those stars are I mean that's almost completely useless not even the fine detail can be used because I mean it's completely blurred out that's with sulfur I think maybe oxygen that one's a little bit better but the stars are still completely blurred out hydrogen-alpha they're fairly sharp but it's still not as sharp as it should be and that brings us all back to the very first problem I set at the start of the video where when I was aim of this region of the sky with my baton of masks there was nothing bright enough for me to focus on and since I'm using a sky got her pro I couldn't just say go to wherever I wanted with a bright star therefore my life was a lot more difficult I couldn't get the focused on and I ended up wasting about an hour because not as data is usable as far as I'm concerned it's too blurry so I think my number one tip from this whole video is that eh if you're gonna be shooting with narrow band during the full moon or in a region where there's not a lot of bright stars try and focus your lens on Polaris or something else with the badenov mask with the filters in place that way when you actually find the object it should be pretty focused but don't forget that hydrogen alpha oxygen and sulfur they're all gonna have different focal points so that way even if it's sharp with hydrogen alpha it doesn't mean is going to be sharp with your other two filters so you can see that there are some problems doing this that's where maybe that electronic focus or might come in handy that zwl has something more to consider but I still like doing things of the hard way and giving myself a challenge at night apparently and even if the data was good I still messed up the live stacking which we talked about and as I mentioned I don't even like doing live stacking that I've seen you have to do everything before taking your light frames to me that doesn't work out I'd rather take those after my light frames and just do it all in post and for my final image as you saw it was too blurry to do anything with and this is really all I got out of it at the end of the day I'm not really happy with it but I learned a lot and on my next night I can fix 90 to 100 percent of the problems I encountered and I should be able to get a lot better a final photo than this which is not good at all so thanks for watching hopefully this video will save you from making the mistakes I did and you'll have a bit of a smoother night maybe now you know what to do live stacking a little bit better or maybe you don't even want to waste your time with it and looking ahead to the rest of the dedicated Astro course I still have a lot of videos I want to do and I want to get back to me actually showing you how to do things rather than me explaining all my failures but I thought at least for these past two videos it would be good to show you the mistakes I made that way you don't repeat them as well [Music] you

Channel: Peter Zelinka

Views: 42,716

Keywords: live stack, asiair pro, asiair, astrophotography, lagoon nebula, astro, stacking, zwo, asi 1600mm pro

Id: U3FS3fson3k

Length: 26min 39sec (1599 seconds)

Published: Wed May 06 2020