imakebeer

I'm continuing to hone my skills in all respects and had another go last night at M31 & M33, and I feel like it's an improvement over the last attempts here. I think the M31 pic is less noisythan before and the stars in particular seeem really bright though I'm not sure why. M31: 81 lights at 60s & ISO 400 + 10 each darks, biases and flats. M33: Only 18 lights at 60s &ISO 800 + 10 each darks, biases and flats - not for the first time I was undone by a flat battery in the camera! 😭😭😭 Have now ordered a dummy battery! Stacked in Sequator and fiddled with in GIMP - @Rallemikken I took your advice and tried Siril, but at the moment I just seem to get better results from Sequator. The Siril tutorials are good though, and I can see it's a very powerful tool - I think part of the problem is I'm not sure at what stage to switch over from Siril to GIMP. The learning journey continues.....

Just a thought from a newbie; Back in my motorcycling days I always used to carry a sidestand puck under the pillion seat - if you go to a race for example and have to park in a grass field you put it under the sidestand to stop it sinking into the grass and your bike (~200kg?) falling over. If you're not familiar, it's a thick plastic puck about the size of a soap dish/palm of your hand with a raised lip around the edge to stop the sidestand sliding off. Anyway, one of those under each foot of your tripod might do the trick if you don't want to install anything permanent.

I've been making my first steps into DSO imaging over the last few weeks and made decent progress so far but want to continue improving. One thing I'm uncertain about (and I realise there's probably no firm answer) is how to know how many light frames are enough? And within that how to decide on the exposure time and ISO? I posted some images the other day of M31 & M33 (SW150PDS + HEQ5 + Nikon D5500 + BYN): For M31 I took 60 x 15s lights at ISO 800, plus 10 darks and I'm reasonably happy with the result (I did also take 10 bias frames, and next time I'll do flats properly too). For M33 I was hurrying and only did 30 x 15s lights at ISO 1000, plus 10 darks & 10 bias. Next time I'll plan better so I can take my time. When I compare with similar images from others it seems like they are maybe taking more frames, and definitely at considerably longer exposure times (2mins+ ?). At the moment the best I can manage is about 60s before I get star trailing, but I can work on improving alignment and I'm working on getting tracking set up so this will hopefully enable longer exposures if they're needed. So how do I know when I have enough frames, are there any rules of thumb? This would be help me plan the imaging session better ahead of time. And assuming the ISO stays low enough that there isn't lots of associated noise/graininess, what are the pros & cons of more images with short exposure but higher ISO, vs. fewer images with longer exposure and lower ISO? BYN shows a histogram - besides the peaks not being all the way to the left or right, what specifically are we looking for? In contrast to M31, M33 is much fainter - so how does that change the game? Is it simply a question of getting more lights, or do you need to go to higher ISO/longer exposures (I guess the latter means capturing more photons, right?) Thanks in advance 👍

Great job @Sarek👍I see now what you mean about similar gear, and it would also appear similar targets 😂 Regarding DSS, do you have any links to tutorials/videos? For GIMP I used this one from Astro La Vista - doesn't mention masks at all (and it's all I've looked at so far) so I presume different to whatever you've watched, and also it's clear that I still have so much more to learn about image processing! 😱 Regarding capture, are you just using the HEQ5 unguided? I am - but since we're probably at similar points along the learning curve I'm interested what we can learn from one another. Also, what software are you using to drive the 700D? I've found BackyardEOS/BackyardNikon very easy to get to grips with

I did actually take bias shots but haven't done any flats yet. In a cruel ironic twist, Sequator doesn't give the option to use bias, though it can use flats! But it is really quick and user friendly! @Rallemikken was telling me I should really move on to DSS/Siril for more control, which I'll do, it's just one step at a time. I've done some 60s lights before (the previous night!) which worked OK - to some extent I was being lazy with these ones as I didn't get outdoors until later so I did more lights at shorter exposure times (15s). I did 1-2 test frames at 120s but got star trailing - I think the mount is already fairly well aligned but maybe I need to make it even better. I do actually have a guide scope and camera in boxes but haven't yet got to the point of setting them up yet - perhaps that's the final key to enable really long (i.e. 120s+) exposures??? That's a bloomin' good point right there - there are some things I know I don't know, but frankly I've no idea what else I don't know! 😱😂

Out again last night, great to have had two clear (albeit very cold!) nights in a row 😁 Any tips you guys can share are welcome. Yesterday I posted some images of M31 but a flat battery meant I wasn't able to take any dark frames - so the first thing was to put that right. I stuck with my trusty Nikon D5500 this time + SW150PDS + HEQ5. 60 x 15s lights at ISO 800, plus 10 darks, stacked in Sequator and tweaked in GIMP. I'm really pleased with this as I've only been at this a few weeks - most of which were cloudy, so go figure! I think the addition of some dark frames have improved it. Compared to the previous night's effort linked above I think the dust lanes are sharper. Nevertheless I can't help but wondering what is the difference between this and the amazing images I see on the forum? Is it the equipment? Is it at capture, many more light frames needed, different exposure or ISO? Or Stacking? Or processing in GIMP? Or all four? One criticism of my own images is when you look closely they all look very grainy (=noisy? You can see the individual RGB pixels I think. But I don't know the source or reason for this) Anyway, here's the pic: It was getting late but I figured while I was out with the scope pointing in roughly the right place I'd have a quick crack at M33 Triangulum Galaxy. Still D5500 but this one is only 30 x 15s lights at ISO 1000, plus 10 darks. This one is not so good but it's a start and something I can work on - the galaxy is just about discernable and it looks like a decent pic would show the swirling spiral arms, right?. I was pleased at least that I'm getting the hang of the HEQ5 that I was able to make it slew to an invisible target! 😂

Thanks @Rallemikken 👍 Lots of things to learn, but yes I'd like to get the hang of DSS at some point. I haven't heard of Siril before though - what does it add that DSS and Sequator don't?

Thanks again for your advice folks 👍 If you're interested, I've posted the finished pic here - M31 isn't great in the end but I'm pleased with M42 😁

I got out last night for what feels like the first time in ages and finally got a decent few hours to put my new gear through its paces. I've posted some previous DSO attempts with my Nikon D5500 + 18-300mm lens on a fixed tripod (here and here), but I've now upgraded my gear to a SW150PDS + HEQ5, and I wan't going to be deterred by the full moon. Or the street lights. Or the Xmas lights! I had a go doing some planetary and lunar first but these have turned out poor. Then I moved on to some DSO... I started with M31 and my Canon 450D - 30 x 60s at ISO 400 lights - but the battery died so I never got a change to take any dark frames which I think shows in the output 😭😭😭 Nevertheless I put it through Sequator and GIMP and here's the result - I need to work more on post processing and next time I'll do a better job of capturing (any advice welcome!). But it's a big step forward from my previous attempts with a DSLR on a fixed tripod! I had to swap out the Canon for my trusty D5500 and since Orion was coming up I figured I'd have a bash at M42. I have to say I'm super chuffed with this for a newbie! I don't know how much is luck, how much is the camera (much more modern than the 450D) or what - but even in the raw light frames the colours and these twinkly-star-shaped stars (what do you call that by the way?). 60 x 15s at ISO 400 lights PLUS 10 dark frames! 😁😁😁 Sequator again to stack and some random twiddling in GIMP - again, all suggestions and advice welcome (I think the next logical step is to try M31 with the Nikon):

Yeah, I've just run it through Sequator (like DSS except user friendly and easy!) again and changed the Composition mode from Accumulation to Select Best Pixels. Seems to have done the job 👍 Edit: I went back to sequator and "Composition mode = Accumulation" + "Remove dynamic noises = On" seemed to do a better job

Thanks @Rallemikken @Padraic M 👍 Looking through the light frames I can see the dead pixels now, they are fixed in the frame as the target moves a little. I guess sequator has made them trail when I stacked - I'll see if there is a setting to deal with them. As I mentioned, had my battery not died I'd have done some dark frames too. @ONIKKINEN I don't quite understand the question. The mount was tracking although it is unguided at the moment (on my to do list!). I've heard of dithering - I've see the option in Autostakkert when processing planetary videos but beyond this I don't know what it is. Something else to learn!

I was out imaging M31 Andromeda Galaxy last night - Canon 450D + BackyardEOS mounted on a SW150PDS + HEQ5, 30 x 60s exposures at ISO 400..... Now the battery in the DSLR died before I was finished so I only took light frames, I didn't get a change to do any dark frames. I've run the light frames I have through Sequator to stack them and now in GIMP to play around some more - from Sequator I can see there are these red, green and blue streaks. I've doctored the image below in GIMP to make them stand out. They look like streaks of coloured rain running from top right to bottom left. Any idea what is causing them?

@Dave scutt you absolutely can do planetary with a stock Canon 450D attached to your telescope, and it absolutely does do video 👍 See my threads here and here The gear I used was very basic, a 70mm/900mm frac on a manual EQ1 mount plus a few other bits. IMO the key is to use BackyardEOS on a laptop to drive the 450D - you can get a free 30 day trial. It has a planetary mode with 5x zoom that captures a much smaller part of the sensor. I don't recall the settings I used, I think I was playing around with ISOs around 800-1600 (can check if you want). Is a dedicated planetary better than a DSLR? Maybe. But a guy on CN pointed me to his experiments of a Canon 600D/700D compared with a ZWO. Although the latter has a far faster frame rate it is more noisy and so needs many more frames. I've recently acquired an HEQ5, SW150PDS and a couple of planetary cameras. If it ever flippin' stops being cloudy here 😖 I plan to play around with different combos of all this gear (450D included) to figure out for myself what works best for me - and hopefully improve considerably on the images shown in the linked threads above!

I'm gonna preface this by saying if I come across a rude or ungrateful for asking for help and then not taking it, this really isn't the case. It's more that I tend to learn things by arguing when things don't make sense (I still remember doing this with my A-Level physics teacher, not that I ever won an argument!). All of your comments are genuinely very helpful because it's making me question stuff and figure out the answer and get it straight in my own head. Sincerely, thank you all for your help 😁👍 I'm still not buying the argument that I messed things up by doing the Synscan handset polar alignment after the 3-star alignment. If this was the case how come Polaris was outside the polar scope FOV at the start and inside the FOV afterwards, surely that's an improvement? @StevieDvd has beaten me to it by posting a link to the Synscan manual, which I was already looking at earlier - the manual is clear that the polar alignment routine is only available after you do a 2- or 3-star alignment so why on earth would SW hide it initially if it wasn't meant to work this way round? (but I do agree if you did a traditional manual polar alignment through the polar scope using the HA of Polaris then no, you don't want to mess with the alt. & az. bolts afterwards) In this regard, the YouTube videos are just repeating what the manual says. However, what the manual goes on to say (and the YouTubers don't make clear, but @StevieDvd notes above) is: "Go back to the “Alignment” menu on the SynScan hand control and execute another 2-Star or 3-Star alignment... Repeat [ ] until the error is small enough and acceptable. Generally, users can get up to 1 arc-minute polar alignment accuracy after repeating this polar alignment process 2 or 3 times." So actually I was (by luck rather than judgement!) on the right track when I started to do another 3-star but fog stopped play. My hunch is that had I done it a couple more times then Polaris should have ended up where it wants to be in the Polarscope reticle. With regard to mechanical backlash the manual also notes in a couple of places that: "When centering an alignment star in the eyepiece, the operation should always end by using the UP and RIGHT direction keys to move the axes." @Knighty2112 pointed this out above too - I didn't know to do this, but will do so in future (oh and the manual also says what you said about using a higher magnification eyepiece for alignment or one with crosshairs 👍) The point about making sure the polar scope reticule is correctly aligned with the RA axis - yeah, I'd seen some videos about this. I haven't checked but it's on my to-do list 👍 My gut feeling is primarily I'm really not helping myself by starting with polar alignment so far out of whack - I can see Polaris clearly from my front drive or back garden (well, I could if the flippin' clouds ever cleared!😖) so better to start off as close as possible. @Owmuchonomy (great username BTW 😂) to answer your question right now I'm neither observing nor photographing 'cos I'm still trying to get the hang of this new mount! 🤣 But ultimately the plan is a bit of both - and sure, I understand that for observing you need not be quite so precise but for AP you need to be spot on. I've already had some experience doing planetary AP with our EQ1 + Capricorn frac, including having to tweak both the RA and Dec. because it's hard to get everything spot on with this mount! With the HEQ5, besides a lot more heavy lifting 💪🤣 you've got tons more options to help you get it spot on. My gut feeling is once it has clicked then it's really not that hard to get very close alignment pretty quickly regardless of visual or AP which is why I'm trying to get it straight in my head now. I took some time to get my head around setting up the EQ1 which was time well spent so I'm confident the effort now with the HEQ5 will pay back soon. Again, thank you everyone for your help and suggestions 😁👍🔭

I appreciate your suggestion but I'm struggling to buy this explanation... If this is the case then how come (a) the polar alignment option in the handset doesn't appear until you've done a 2 or 3 star alignment, and (b) there are videos aplenty on YouTube of folks demonstrating this technique, including showing how it reduces the assignment error? I'm also not sure how it differs from Sharpcap where you align based on stars and then adjust with the alt. & az. bolts 🤔

Good point. I didn't know that but obvious now you point it out. I'll try a star next time. I don't believe it's more than 2-3 years old and barely used from what the seller explained to me (a forum member so I can check). As much as I'm new to this I'm not completely daft with mechanical things and my gut feeling doesn't tell me there's anything untoward going on mechanically.

Thanks @Budgie1, all clear, but... No problem, I have about half a dozen of these apps on my phone now! 😂 I will absolutely go back out at the earliest opportunity and follow your advice, but... ...what I don't get is why this manual polar alignment is necessary? I mean, sure, if you're not using the handset or Sharpcap etc to do your alignment for you then absolutely I can see you need to align your mount manually like this - it's what I've been doing previously with my EQ1, albeit without a polarscope 😂 And I can certainly believe that if you take the time to get the manual polar alignment as good as possible in the beginning then you're making life easier for yourself later on. But assuming you're not doing it manually then you do your 3 star alignment and then the option appears on the handset to do a polar alignment (there's a video here going through the complete process) - the latter prompts you to adjust first the altitude bolts, and then the azimuth bolts. And presumably the whole point of that final handset-guided polar alignment step is it's getting your RA axis bang on inline with the Earth's rotation (and as noted above my polar alignment was less wrong at the end than when I started!) And even if anyone was inclined to tell me to "just use Sharpcap ,it's so much easier etc etc etc..." from what I see of the YouTube videos this method still requires you to adjust the alt. & az. bolts so is presumably doing something similar to the Synscan polar alignment??? Perhaps my tripod was too out of kilter or the mount too far away from Polaris to have worked at the first go. I did actually get the tripod more level and start the 3-star alignment again but alas was beaten by the fog ☹

I managed to get out for just an hour last night before the fog rolled in. This gave me a little bit of time to practice with my new-to-me HEQ5..... (and to save you some time, please don't just tell me to polar align with Sharpcap - I'm working on this too, but I want to understand everything and not just skip to the answer) I set up and got the tripod level (though in hindsight not as level as I perhaps thought) and pointed roughly at Polaris... I didn't use the Polarscope to get it bang on though as I understand this is kind of the point of 3 star alignment. I checked that the time and my local lat., long. and altitude in the handset were all correct. Then I ran through the 3-star alignment using Capella, Mirach and Vega - this worked fine now that I've sussed you can alter the slewing speed 👍😁 I got all 3 stars dead-centre in the spotting scope first and then fine tuned through the eyepiece. I didn't have to do much adjustment, the software got me 98& of the way there each time and each star was already visible in the spotting scope, albeit off centre. Once I was done with 3-star, I ran through the polar alignment which prompted me to adjust first the altitude bolts and then the azimuth bolts, which I did and got Vega dead centre in the eyepiece again. Job's a goodun' , or so I thought, and figured righto, let's have a look at Mars - the scope slewed round but I found Mars was off to one side. Sure I can correct with the handset but after doing the alignment I expected Mars to be pretty much dead centre in the eyepiece. I double checked through the polarscope and Polaris was visible though well off centre and well outside the 0-3-6-9 clock circle. So where am I going wrong? Have I got to get the tripod bang level at the start? Have I got to get Polaris bang on around the clock through the Polarscope? What else? I finished the hour feeling like I had learned more than when I started so it was productive, but clearly there is still more I need to learn - just need a few more hours of clear skies! 👍🔭🤞

Damn straight - the Pleiades isn't exactly the brightest thing in the sky but even in my own paltry efforts it's amazing how there are so many more stars in the background!

I'm just a newbie but now you mention it I feel like at least the last couple of decent sessions I had were around the full moon 🤔 Anyway, I managed to get out just now but only for an hour before the fog rolled in - turns out grab & go with an HEQ5 is a different ball game to an EQ1 but I was determined! 💪 If nothing else at least it was an hour well spent getting the hang of 3 star alignment 😁

Me too. In fact if it ever stopped being cloudy I might learn 2 or 3 new things every day! 😂

Thanks 👍 Any idea what LET actually stands for by the way? I wear glasses but I can't immediately see how the twist up eyecup helps, early days yet though. It's actually just a single hole on the PDS - I think the second one is just something to grab. I just double checked though, and it's definitely fixed. But I get what you mean about focusing, a bit like a Bahtinov mask I suppose. Noted 👍 My eyesight is dodgy enough as it is without me going staring at the Sun though. Night time only for me 😁

This doesn't answer your question but while searching for something else I stumbled upon this article on Astro Baby's website which might at least help you get the most out of your current focuser: https://www.astro-baby.com/Skywatcher Focuser Tune up/Skywatcher Focuser Tune-up.htm 🔭👍

A couple of questions actually: First, as per the title, both my new SW 150PDS and our SW Capricorn refractor have a lens cap with a hole and a smaller lens cap. What's the point of that? I note that with only the smaller lens cap removed you can still see pretty well through the scope. Is it something to do with heating/cooling the scope, or dew maybe? Or something to do with limiting the amount of light you're capturing with bright objects maybe? Second, the 150PDS comes with this mahoosive 2" eyepiece - "Eyepiece Supplied: 28mm 2" LET" according to the FLO blurb. I tried Googling LET but couldn't find what it means. Anyway, the rubber eyepiece shroud (?) screws in and out - it doesn't zoom but rather seems to change the field of view wider/narrower. Why's that then? TIA 👍🔭

Welcome @GeorgeP, I'm just down the road from you in Wokingham so most likely we are sharing the same permanently cloudy skies! 😖🤣