Dithering with the ASIAir Plus & EQ6-R Pro

hey guys i'm finally back here on youtube i know it's been a while since the last video uh there's just been a lot going on behind the scenes one of the big things is that i recently moved from utah to washington and up here we don't exactly get a lot of clear nights which has prevented me from doing any astro but tonight here on clear dark sky charts you can see we've got a pretty good night all things considered so i'm really looking forward to getting all the gear out and see what i can do and when i moved from utah i mean back down there in kanab we had about as dark as skies as you could ever want if you drive even 10-15 minutes out of town just completely dark and that was awesome but up here in washington i have a new challenge and that is all the light pollution i'm going to be dealing with which will actually be beneficial because now i can actually show you guys how to alleviate a lot of these light pollution related problems and that's something we're going to focus on here in the next couple months but that's kind of what's been going on behind the scenes we're going to be dealing with uh cloudy weather now and light pollution but i think it'll be a fun challenge so with that said i'm gonna go grab my gear and we'll start getting set up [Music] so here's a look at my new shooting scenario one of the problems at the new house is that we've got a lot of telephone cables on the other side of the house which is going to ruin the night so for now i'm here on the little back porch and we're going to be shooting up just to the northern sky tonight i'm going to be doing the heart nebula because if i try to do anything else things are getting in the way so that's one of the new challenges i face is that in kanab i pretty much had a clear view of any portion of the night sky but now i'm kind of limited to where i can shoot for now until i get further out in the yard but i figure until i get a dew heater this is a good place to set up because on the pavement we shouldn't have nearly as much moisture [Music] as you can see i'm still keeping my rudimentary set up here i've got my two batteries just on a cheap table got the asar plus which has been doing an awesome job and still rocking with the space cat the filter wheel and the monochrome camera this works really well especially here in the light polluted areas because the narrow band filters allow me to cut through that light pollution really well [Music] once i untangle these big rats nested cables and have everything connected then i can balance my right ascension declination and then after that i'm pretty much good to go but the it won't get dark until after eight so i just want to get set up while it's still light up and one of the problems i mentioned earlier that i'll probably face is that we have do now that's something we've never had in the desert and that means i'm going to need to find a way to deal with that i have a cheap little usb dew heater on the way which should just wrap around here and then get powered by the asr plus we'll see how that works i'll probably do a separate video for that one of the great things about this workflow is that it is so straightforward and in fact as you'll see later i don't even really need to ever crouch down and look through the polar scope anymore that was one of the issues a lot of people had is trying to look through the scope and do a visual alignment but now that we have the asir plus or the pro whatever you have you can just do everything through the software and just make your adjustments once it tells you what to do so there's a lot of reasons i love using this workflow not to mention the fact that having the go-to mount just makes everything so much easier especially when you're shooting a narrow band so we're already almost done with our setup for the night and then we can go in the house warm up and get some dinner so i'm gonna finish connecting these cables and then we're gonna balance our right ascension and declination so there we go tighten that down it looks like my right ascension is already balanced so cut that down there and then for your declination this is pretty easy as well you're just going to turn everything make sure neither side pulls down we look good there all right we're pretty much set up and ready to go so at this point i'm just gonna leave everything where it's at and we'll pick back up after the sun is set it gets dark out we're gonna do our polar alignment through the app we'll do our focusing then we'll start shooting [Music] all right you guys should know the drill by now the first thing we want to do is focus our lenser telescope with the help of a bat knob mask just to make sure we're as sharp as possible and i normally focus with the l filter first just because it's bright and easy to see those diffraction spikes but because i'm going to be shooting with an h alpha filter next i might as well zoom back in change to the h alpha filter and take another photo because chances are it will be slightly different than the focus point for the l filter and last night i ran into some really weird problems with the asr plus as you can see here it's not as responsive as it should be it was downloading the photos at like 100 kilobytes per second it was losing connection this was very unusual and i wasn't sure what was going on thankfully it was just a problem with my phone and i restarted the phone and it worked flawlessly after that i also brought out my ipad in the meantime and i had no issues whatsoever so it doesn't appear is actually an issue with the asr plus it was more so my phone was acting up if you encounter a similar problem where things just don't seem to be working properly try restarting your phone and that might very well fix the problems anyway once i got my focus looking good for the h alpha filter then i was ready to move on and do my polar alignment i always recommend you change back to the l filter take off the bat knob mask and then click on preview change that to pa for polar line and believe it or not when i did that initial setup earlier in the video it turns out my polar alignment was only about two degrees off so that just goes to show you if you go out there and you practice from the same spot night after night in my case i've only done this once but i know where polaris is at i can set up the mount even during the day and still be fairly close then with the help of the asar plus software i know exactly how to move my mount for a perfect polar alignment and i never have to crouch down and look through that polar scope again which is a nice change so you've already seen this part of the workflow punch basically with the go to mount it does everything for you when it's complete it's just going to tell us to move up or down left or right a little bit we make those adjustments on our base and we're good to go when it comes to your total error in this case 41 minutes 25 seconds i like to get that down below 5 minutes and that's usually good enough for what i'm doing if you had 2 000 millimeters or something like that then it might be worth the extra investment in time to get that total error as close to zero as possible but right now i'm only at 500 millimeters and in my experience again if i can get that total air down to five minutes or less i usually have great results and the problem we're gonna run into is anything below that here we are at three minutes uh you're just gonna be chasing your tail and you'll make a small adjustment and it'll be too far one way and it just gets very frustrating so we're done with our polar alignment it's that easy now we need to move our mount and more accurately our telescoping camera to a random portion of the night sky because if you try to plate solve aimed up towards polaris it's not going to work so we use those arrow keys there either up down left or right press and hold when your telescope is now moved away from the north or south celestial pole we can take another photo with our new photo displaying here on the screen we'll click the plate solve button on the left that will analyze the stars it will tell us where we're aimed up at then we'll click sync mount now that our mount knows exactly where it's aimed up at it knows how to get to whatever you want to photograph so up in the upper right it says ic1805 which is the heart nebula i've already dialed that in i'll click go to and now it's going to automatically move the telescope directly to the heart nebula and it's really amazing just how well this works so if you're still controlling your mount entirely from the hand controller and you're getting fed up with the three star alignment and all that junk you should really consider first of all making sure your mount is compatible with the asar software and if it is and you can actually get a hold of an asl or plus it's going to be a game changer for you because as you can see here it's just so streamlined and simple provided everything's working properly but there we go we now have the heart nebula centered up there in the frame kind of hard to see with the l filter so i'm going to change to the h alpha filter we'll take probably a two minute long photo just to see what we're in for and then once we get that running we can get the rest of our workflow started tonight i'm going to try dithering for the first time here on the go to mount the way dithering works is that after every single photo you take your camera and telescope will move slightly in a random direction and the end result is that after stacking your image should have noticeably less color model and walking noise and things like that so if you go into your guide settings and then into the dither settings you can just flick the switch there to turn on dithering the pixels i like to go with 10 that way i get a noticeable amount of movement between each photo if you only have like one or two then the camera might not move enough between each photo to get any noticeable difference so i'm going to go with 10 today the interval should be left at 1 that way after every single photo you have the dither applied and because we have the go to mount r8 only should be turned off if you had a star tracker though aria only should be turned on after we back out of the dither settings we're gonna go to the guide stability settings next to further tweak our parameters and in the guide stability settings the main thing you want to do here is make sure that the stability and settle time are set correctly this might sound kind of confusing but basically the stability there where it says point six seconds one two three or four that's your accuracy in arc seconds so the lower the number there the more precise the guiding has to be which means you're gonna wait longer before you can take your next photo the settle time is how long it needs to maintain that arc second rating so it explains it pretty clearly there this will make more sense once we get to the guiding interface but i'm probably going to go with a rating of or rather stability of two seconds and a subtle time of three seconds my thinking here is that i don't want to waste a lot of time between each photo because that could really add up over the course of the night and maybe if clouds are rolling in at a certain time i might end up shooting myself in the foot so i'm trying to reduce the amount of time i have to wait between each photo in my case today i think we'll go with a stability of two seconds and then a subtle time of three and then that should work pretty well for us tonight now that we've got our dithering settings dialed in let's head back to the preview window looks like we're just in time we're going to see if that h alpha photo turned out okay my main goal here is to make sure that the composition looks good and yeah that looks great we got the heart nebula right there in the center of the frame so we're good to go there let's click on the guide button on the left and begin our guiding so once you click on the guide button on the left you can double tap on the graph that pops up that will bring you to the guiding interface and this is really easy to do here on the asr plus just click the begin looping arrows there on the right you'll now start taking photos with your auto guider in this case it's already fairly well focused and then you can click the begin guiding crosshair button on the right there and it will automatically choose the best star so in the past i always said to tap on a star and then click begin guiding but now you can just click begin guiding and it will automatically do what it needs to do at this point it's going to go through the calibration so you can just sit back and wait but i always like to get my camera settings dialed in while this is running and over there on the right we have ra aggression deck aggression deck mode i normally just leave with the defaults and it works well for me so we'll click the two arrows in the top left corner to get back to our camera interface here then we'll change from preview to auto run this is how we actually take photos with the asa or software once you click on auto run click the three dots and three lines that will bring you to your camera settings and then from here you can dial in whatever you'd like i'm going to take a set of h alpha photos first and then a set of oxygen and that should be good enough for the heart nebula i want to take probably 22 images tonight really i want to get 20 so that'll give me two if they're bad is extra my exposure is five minutes long that should be good enough for the narrow band and then we want to repeat that settings for the oxygen filter and then at that point we're ready to go i will be taking dark frames the following night because it's going to be cloudy no sense taking them tonight when i should be capturing more light frames so there we go we're already set up and ready to begin taking our photos i can back out of this window and then we can check on the progress of our guiding calibration remember you want to double tap on that graph to get back to the guiding interface and then this would be our time to make sure that we're on east step three that looks good that means we're almost done once it completes with its west and east steps then it'll go north and south and when it completes all this you'll have the green lines and you'll begin guiding at that point we can start taking our photos so we're almost ready to go alright so we're now officially guiding we see the red and blue lines there on the graph i normally like to give them about 10 seconds to settle down and get as close to that zero line as possible but from here there's nothing left to do other than begin taking our photos for that we can click the two arrows in the top left corner to get back to our shooting interface and then we'll just click the big circular button and start taking our images i almost forgot to mention that before you start taking your photos you should turn on your camera's cooling system which you can do through the main camera settings if you forget like i did then when you click the circular button to start taking your photos it will actually tell you hey your cooling is off do you want to turn it on and that's just a nice reminder so once you've reached your target temperature in this case minus four degrees fahrenheit then you can start taking your images like we're doing right now so i'm going to sit back relax and wait five minutes for this photo to complete and then we're gonna wait for the next photo to see just how well this dithering works okay we're just about done with the first image and as you're gonna see here the new photo will load up on the screen looks quite a bit cleaner there and more detailed and if we look at our graph there it should give us a big dither sign which means it's going to stop taking photos it's going to randomly move the camera in a direction there you can see the dither and once the guiding stabilizes for a set amount of time which we did earlier in the video then it will begin taking the next photo so you could always double tap on the graph you can see there's the big spike on the guiding that's okay that was the dither and we just need to wait for our total error to get down below two arc seconds or so and hold that for about three seconds once it does that it will automatically trigger the camera to begin taking the next photo and there we go we're already on our second image for the night so again we're going to sit back and wait and then when this photo completes we'll see the difference and how much the camera actually moved with the help of the dither at this point let's all pick a star to lock our eyes onto and when the new image pops up we'll see just how much of a star motion we had between our first and second photos that was a decent amount that was using 10 pixels if you remember earlier for the dither settings i could have gone as high as 30 but i thought that might be a little bit overkill and based on these results i'd also recommend you stick with 10 pixels because that seems to work pretty well but now that we're done capturing our images let's head over to the computer and begin our processing we're going to start off here in photoshop and i want to show you what ultimately led me to try dithering this photo of the triangle galaxy was taken a couple weeks ago and i was pretty disappointed with the data because as you can see there's kind of this weird left right streaking pattern and it just looks really gritty and i know that when you're shooting in narrowband you really need a lot of data to get a clean photo but it still look like there's some weird streaking going on that i wasn't used to seeing in my photos so this is really what prompted me to try the dithering because i thought it could solve it that's kind of where i started off at just so you can kind of have some idea what you might want to look out for in your images as well another example of why you'd want to try dithering is right here this is a great photo i found online to showcase some of the problems you'll notice we have just overall up and down streak throughout the photo and also you can see there's red blue and green splotches which i normally call color model so between the walking noise and the color model we have two pretty severe problems that are detracting from this particular photo and the reason we do dithering if we look at our last example here is that let's say our first photo is taken here and then the stars move up here in our second photo and then on the third they're over here fourth maybe they're down here ultimately it should be kind of like a spiral from your first to your last photos i should also stress that the more photos you have then the better the dithering should work because the more images you can average together and the end result is that it should smooth out any kind of walking noise and color model because now the green splotches that are always located here on your sensor are going to be shifted all around and the red green and blue all come together and neutralize so that's really what we're trying to do with the dithering for our comparison today we have an image taken just like we saw earlier in the video with the dithering applied but the week prior i also photographed the heart nebula this time with no dithering and so this will give us the perfect way to test before and after how the dithering works i should mention that i had about 20 images for both h alpha and oxygen on the non-dithered and the dithered photos so frankly that's kind of low on the amount of photos 20. i'd like to have 30 40 50 or more which should increase the benefits of the dithering another problem you might notice if you look closely is that these photos are still really grainy even after about two hours of data for h alpha and two hours of data for oxygen the image still is nowhere near as clean as i would like it to be and that just goes to show you that when you're shooting a narrow band you really have to invest a lot of time in this data to get the best possible results in my case i'm looking at at least another night maybe two nights of data collection before i have enough signal to reduce the noise visible right here with all that out of the way though let's actually do our side-by-side comparison so if we zoom in far enough i'm really not noticing any kind of color model or streaking noise pattern in the dithered photo if we look at the non-dithered photo there's a little bit of streaking you can see right here actually we have a a left right line a left right line a left right line it's subtle but there's definitely something going on there and when we compare that again to the dithered photo i'm not seeing that at all so it's actually pretty hard to see with a monochrome camera we don't really have the color model necessarily and the walking noise seems to be greatly reduced from that triangulum photo i showed you earlier so to be honest this probably wasn't the best comparison even though i did the best i could the data just doesn't look as bad as i guess it could have and it's pretty hard to see the walking noise even on the non-dithered photos there might be a little bit here if we compare that to the dithered image again it just looks like a uniform noise pattern so i'm not really too concerned about that and here i still see kind of some left right streaking in the non-dithered photo so i wish the comparison could have been a little bit more obvious but that's the way it goes sometimes and here's a zoomed out version of the dithered image versus the non-dithered there's a slight color balance difference but that's just because of my processing overall from here you never really tell the difference and i guess that's one of the things is that as long as you're capturing good data and you're doing everything correctly and you've got a good camera then even without diving you should still be getting good photos but if you are noticing some serious problems in your photos whether that's the color model the walking noise or both then if you have the ability i highly recommend giving dithering a try when you're using a go to mount and the settings i showed you today it should give you at the very least slightly improved images and it won't cost you very much time you might have remembered back when i did my first video on dithering with a star tracker and i really didn't recommend it back in the day because when you're trying to dither with a star tracker it's really just a waste of time to be honest but here with the go to mount i think it is a good idea you're not really wasting any time and you're getting better results so my final word on dithering as of right now is that if you have the ability you might as well try it and it might actually solve some of the problems you've been having and that's all we've got for today's video i hope at the very least you learned something about dithering and if you want to give it a try now you know exactly what to do if you want to learn even more about astrophotography i do have a patreon page i don't really talk about it too much but if you want to check that out i'd recommend the 10 a month option that's where you get most of the tutorials and we do something a little bit different every month last month we did a star trails a couple star trails tutorials and then we did some andromeda stuff depending on what you're interested in you can kind of scroll down through here get an idea of what we're doing and if it sounds interesting you can check it out that's all i've got for you today thanks for watching sorry for the long wait looking ahead over the next couple months we are going to be doing more light pollution style tutorials and how to avoid it because i'm now in the light polluted area and we'll get into some new heaters and things like that so that's what i've got for you today and i'll see you guys in the next video [Music] you

Channel: Peter Zelinka

Views: 39,243

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Id: eFS1tOT0jy4

Length: 23min 12sec (1392 seconds)

Published: Thu Oct 14 2021