-
Posts
265 -
Joined
-
Last visited
Content Type
Profiles
Forums
Gallery
Events
Blogs
Everything posted by imakebeer
-
How to attach guidescope to SW150PDS ?
imakebeer replied to imakebeer's topic in Getting Started Equipment Help and Advice
I would say using it mostly for imaging - I don't want to completely give up on visual hence I want to keep the visual finder scope ideally (plus I can see it being a useful backup). I thought about doing as you say, attaching the dovetail to the 150pds rings, then attach the guidescope rings to the dovetail. The issue here is that the bolts for the guidescope rings are smaller diameter than the holes in the 150pds rings and the dovetail so there is potential for some play. -
Since the weather at the moment seems to be terminally cloudy I've finally turned my thoughts to how to attach a guidescope to my SW150PDS - advice from the SGL massive would be much appreciated..... First pic below shows the OTA. Mounting options seem to be either to attach it via the finder shoe circled in red or piggy back on to the tube rings circled in green. Second pic shows the bits I have: Altair guidescope Tube rings and standoff (?) supplied with the guidescope An alternative black finder shoe (?) A green Skywatcher (?) dovetail (?) Also various bolts I can use but they're cheap if I need more So it's a question of whether I can use what I have or if I'm better to get some other bits? 1) Easiest option seems to be to fit the guidescope into its tube ring assembly and attach that to the existing finder shoe (it fits). But it seems like it might be handy to retain the optical finder scope??? 2) I could replace the stock finder shoe with the rather more sturdy-looking black one. I'm somewhat reluctant to do this for fear of dropping the small nuts down the tube or knocking the secondary mirror but I can probably do it. But I still lose the optical finder scope. 3) I'm given to understand that we want the guidescope to be mounted as rigidly as possible so maybe piggy backing is the much preferred option... I'll need to rotate the OTA in its rings to avoid the focuser - not a problem. I think I can fix the spare green dovetail to the OTA tube rings but then what? I'm not sure I can then easily attach the guidescope tube ring assembly to the dovetail. At least, I can probably attach it but I'm not certain how rigid it would be. So am I better off to source some extra bits for piggy backing, and if so, what? Or do I just take the easy option and see how I get on for now. Thanks in advance 👍
-
Thanks for the feedback @WolfieGlos. Yeah I switched off the stretching which improved things. I'll let you know about Siril but based on what you've said I'm not too optimistic, but we'll see.
-
Thanks for the feedback Olly, this is helpful. I agree with you - I'll take a look at the histogram and see if I can tweak in a bit more green/less magenta 👍
-
One thing I always seem to struggle with is noise, particularly in the farfield of my DSO images. I'm not ready to bite the bullet and fork out for software to do this so in the meantime I've been having a play with some free tools. Below is a with/without or before/after comparison of my last M31 capture from January 2023 - stacking and initial processing was done in Siril. @Elp mentioned to me in another thread about trying StarNet to make a starless image. This worked really well and I found it much easier to stretch the histogram in GIMP when dealing with just the galaxy on it's own and so bring out more detail 👍 I added the stars back on a separate later and made them only 25% opaque. I'm pleased with the result as they seem less stark and don't dominate the image so much. Following that I found AstroDenoisePy - maybe paid tools like noiseXTerminator are better but for a freebie and never having used a de-noise tool before it seemed easy enough and did a pretty good job I think. ( @WolfieGlos I saw in another thread you had tried it, I'm interested to get your take on ADnPy) I found it changed the colour quite a lot until I dialled back the de-noise level from the default 0.9 to 0.25. Also I'm not sure if I'm doing these processing steps in the right/best order??? It also looks like the latest beta of Siril had some new de-noise capability so I'll be trying that out too. Anyhow a comparison of the images below. I'm pleased with the outcome of these new techniques, though I've still got loads more to learn and perfect. Any comments, tips or feedback would be most welcome! Original: Siril + GIMP Re-processed: Siril + StarNet + GIMP + AstroDenoisePy
-
The months have kept rolling by since I started AP last October and old faves like M31 and M33 have disappeared for now, but new targets are coming into view. I got the gear out for the first time in ages the other night. Unfortunately I was a bit rushed setting up because reasons and things went a bit awry and I ended up taking nearly 90 light frames at ISO 25600!!! Not to be deterred I reset and pointed the scope at M81 / M82 and managed to get an hours worth of data before it clouded over. Ideally I'd do double this but it's a start and I'm quite pleased with the outcome as a starting point. SW150PDS + HEQ5 + Nikon D5500 60 x 60s at ISO 400 lights + 20 each darks, biases & lights Processed in Siril and then tweaked in GIMP In GIMP I had another play using layer masks. They seemed to work well on M42 when I tried them recently though I'm not sure if they're the best for galaxies like M81 but I thought I'd have a go. One thing I've struggled with in the past is once I stretch the histogram to bring out the detail it introduces a lot of noise in the farfield. If you look closely around M81 & M82 you can still see this noise but the use of layer masks means it doesn't extend across the whole image. As I say I'm pleased with this one as a starting point and I'm excited to try some new targets, but I really want to get to grips with how to bring out more detail.
- 3 replies
-
- 13
-
@Elp @Vroobel thanks for the advice and suggestions, much appreciated 👍 I'm gonna take a look into modified DSLRs, starting potententially with modifying my 450D myself - need to check out the tutorials for this on YouTube. I'll also take a look at StarNet as this seems like it could be useful more generally anyway from my initial look.
-
Hey @Elp , can I pick your brains on this a little more... Up the top of this thread @Vroobel has suggested a couple of Optolong filters - they're not cheap but, well, ok... In the course of my googling I found this thread from ~9 months ago in which you said you'd tested the L-Pro, L-Enhance & L-extreme... In your experience do you think any of these would offer an improvement to my Pacman based troubles?
-
While my Pacman nebula needs more work I'm happy to report I've made much better progress with my M42 First pic below - just for comparison - was an early AP attempt last December while I was taking my first steps (reprocessed slightly when I discovered layer masks recently) Second & third pics are from 5th Feb 2023 - SW150PDS + HEQ5, Nikon D5500, 120 x 60s lights at ISO 400 + 20 each flats, darks & biases. Processed in Siril & GIMP. I made 3 images in Siril with different histogram stretches, then used layers and masks in GIMP to blend them together. I'm super chuffed with the textures in the clouds, looks very ethereal. I want to have another go though - I think I've lost a bit of detail in the dark looking area just below and left of the triangulum, this could be a bit brighter, I just need more practice with the layer tools in GIMP. I think the second pic looks more natural, but in the third one I think I've gone a bit mad with the hue-chroma - what do you folks think?
-
Thanks, I think that makes sense and I had a feeling this might be part of my issue. I need to understand better the different types of nebula. I also have a Canon 450D I bought cheap off eBay last year when I was getting into AP - I might consider modifying it myself or change it for a modified camera. Not sure I want to do this with the D5500 as it's my main family camera. Main issue with the Canon is being older I think it has a slower processor as it seems to take much longer than the Nikon to take and send and image to the laptop. Meh... storage is cheap 😉 I'm intrigued by these filters. They're not cheap - a 2" L-eXtreme is a significant fraction of the cost of my OTA alone. Not that I started this hobby to save money, but still... The blurb about these filters on the FLO websites implies I can just bung one in - I assume inbetween the focuser and DSLR? - and all will be well with the world. Is it really that simple?
-
Thanks. As noted in the OP (😉) Siril and GIMP. The former is sometihng I've been recommended by others on here. Sorry, I forgot to mentioned flats in the OP, now corrected - I did 20 flats too. I seem to get diferent areas of lighter/darker "haze" across my images, I suspect there is a lighter patch just out of the frame which might explain what looks like vignetting. I can see vignetting in the original image but then this version has been massively cropped way beyond this. The reasoning behind doing 60s at ISO 400 is this - from what others on here have told me, it's the total integration time that matters most. So whether you do 100x60s or 60x100s or 20x300s it doesn't really matter. Also, since I've not sorted out auto-guiding yet I find if I go above 60s the star trailing becomes unacceptable. Plus, when a satellite goes across your FOV it only ruins one of many shorter frames. Re. ISO, my D5500 is ISO invariant so if I go above ISO 400 it just introduces more noise. Looking at the histogram it seems like there's enough wiggle room there - it's not like the peak is hard up against either end of the scale. Which is not to say it wouldn't be worth trying different camera settings, just when I've tried it on M33 for example it didn't make any noticeable difference. Hmm... OK, interesting... As noted I did flats, just forgot to mention it in the OP. So maybe in part the issue is a stock D5500 just isn't up to the job for this target??? 🤔
-
I've been making steady progress in the last few months and made steady progress with M31, M33, M42 & M45. So I thought I'd have a go at the NGC281 Pacman Nebula. But I'm really struggling to get much out of it so far - I'm not sure if the problem is simply that it's a really faint target and I just need way more integration time, or if a standard DSLR won't cut it and I need to try a modified/dedicated camera and/or use HOO and/or SHO??? Or maybe the problem is simply light pollution??? I'm in a Bortle 5 - I set the scope up in the back garden away from the streetlights out front, but then my neighbour's landing light is shining down on the scope which really isn't ideal either! SW150PDS + Nikon D5500 126 x 60s lights at ISO 400, plus 20 each darks and bias [EDIT: and 20 flats too!] Processed in Siril then tweaked some more in GIMP. This version is heavily cropped because I wondered if the background extraction in Siril was causing issues, but I'm not sure that's the case. Can anyone offer any pointers? Cheers.
-
Thanks @ollypenrice , and thanks also for the suggestion👍 In addition to layer masks I think I'd also heard about your technique of different exposure times for areas of different brightness. I suppose the big investment is the longer exposure part to get the faint areas (say, 120 x 60s), but from there it's less investment to do an additional, say, 120 x 10s. My only uncertainty here is you'd end up with 2 different stacks - isn't there a possibility they'd be slightly out of alignment with each other, and so how do you ensure your layers are perfectly aligned? (I'm certain it can be done, I just haven't learned how yet!) I suppose it's no different to challenges you might face if you're collecting data on multiple nights, and possibly even related to the challenge of how to merge together different areas of a mosaic 🤔
-
I posted an image of M42 early last December, one of my first pics with my 150PDS, and very pleased with the result at the time. But in an effort to keep upping my skills I went back and had another go at processing it in GIMP, this time using layer masks to try and bring out more nebulosity yet preserve the bright core. The original stack was only 60 x 15s @ ISO 400 + 10 darks, so not ideal. The difference in the processed results is quite subtle but it's definitely there and I'm encouraged to keep trying with this technique (plus when the opportunity arises I plan to re-image M42 capture way more data, like 120 x 60s!) Original Image Re-Processed Image with Layer Mask
-
Umm... What's GHT? I mean, obviously I know, but just in case anyone else is reading 😉
-
Funnily enough I posted a pic of M45 yesterday taken with my 150PDS and precessed in Siril. I think yours is cropped a tad more than mine but I felt like Siril had made the diffraction sounds go a bit bananas and I'm wondering if it's had a similar effect for you. You've done a great job at bringing out the nebulosity though, and I like the colours better then mine 👍 I feel like Siril also results in uneven backgrounds, lighter in some areas and darker in others - maybe to do with background extraction? I can maybe see it a little in yours but not as stark, or I could be imagining it! 😂 So much to learn and such a long way to go with post processing - onwards & upwards! 👍
-
@wesdon1 That's a nice looking image of Jupiter 👍 You should post it up in the planetary section with a few details
-
Continuing to hone my AP skills I went back to M31, plus a bit of M45 since I had the gear setup and time in hand. I still think I've got miles to go with processing compared to the best pics but I'm pleased that I can see my progress in my own work from one session to the next after just a few months. With both of these images I wonder if I'd benefit from getting to grips with layer masks to process the lighter and darker regions separately? Something to try I guess! SW150PDS + Nikon D5500 + BYN. I doubled my previous longest imaging time on M31 from 60 to 120 x 60s @ ISO 400. Same settings for M45 but only 30 x 60s. I also did 20 each darks, bias and flats. Stacked and processed in Siril, plus a bit more tweaking in GIMP. For M31 I think this time I've managed to capture a hint of the finer detail further out - this just really emphasises to me how flippin' big M31 is! I wonder if it's possible to do a mosaic to capture a wider field? (I'm sure it is). I think I can also see some hint of coma(?) towards the edges - I do have a coma corrector that I haven't used it which will also widen the FOV a little I believe so can give it a try. With M45 the framing isn't so good - ideally I'd have rotated the camera to frame it better but I wanted to leave it in place until the morning to do my flat frames. Also something somewhere must have happened in Siril that made the diffraction spikes go a bit bananas!
-
Guidance on light frames, ISO & exposure time?
imakebeer replied to imakebeer's topic in Getting Started With Imaging
Little update - I posted a recent pic of M33 over here. As noted there it was the first chance I'd had to put into practice the tips everyone has kindly given in this thread. Still a way to go but I'm pleased with the improvement over previous images of M33. I think 120 x 60s has made a big difference compared with earlier efforts using only 30-60 light frames. Also it seems ISO 400 is plenty good enough and leaves plenty of leeway for messing with the histogram 👍 Question: I "only" did 10 each darks, flats and biases (vs. 120 lights). Would there be any benefit to doing more of these, say, 20? -
Been a few weeks since I did any DSOs and still very early days for me but I had a few hours to leave the gear to do its thing and put into practice the advice kindly given over in this thread. SW150PDS + HEQ5 + Nikon D5500 120 x 60s @ ISO 400 (+10 each darks, flats & bias) processed in Siril plus fund running in GIMP I'm pleased with the result - I'm still a way behind the best but I only started in Oct 22 and looking at my previous images of M33 the progression is clear 😊
-
Newbie question: I've read about layer masks, particularly relating to M42, so I've a rough idea of what they are and why you might use them in this case. If I've understood correctly you kinda trace round the bright nebula so you can tweak the colours independently of the darker background. Is it a very manual process to draw the outline in GIMP which I'm using in my case?
-
Help me up my planetary imaging game
imakebeer replied to imakebeer's topic in Getting Started With Imaging
Thanks for that @inFINNity Deck, I will try processing my video using similar steps. Main differences for me are I'm capturing in colour, I use GIMP and don't have Topaz yet. I'll be interested to try those settings in AS3! though. Aren't they the same thing, or at least different sides of the same coin? I.e. exposure time = 1 / Frame rate??? From my limited experience in Sharpcap so far (assume Fire Capture will do pretty much the same thing) I could set the exposure time much lower, but then I'd have to crank up the gain... Maybe I'm wrong but in my simple brain I'm thinking of gain as an analogue to ISO, so more gain => more noise??? There also seems to be a relationship between gain and frame rate, or at least write speed to the HDD over USB3, but u haven't que figured it out yet 🤔 -
Inspire me about visual astronomy
imakebeer replied to imakebeer's topic in Getting Started With Observing
Thanks for the suggestions, I'll check them out 👍 Incidentally, while I was out the other night I also had a look at Polaris and - ooh, can't remember now, it was either Rigel or Alnitek, both in Orion - anyway, I was unable to split either... Not sure if these are particularly challenging, but equally it could have been a misted up eyepiece, Polaris was just in the treetops and Orion was just peeking over the top of my house. For some reason I'm also determined to try and see Epsilon Lyrae but as soon as Vega appears it's almost disappearing being trees for me so this might have to wait 6-9 months. -
Help me up my planetary imaging game
imakebeer replied to imakebeer's topic in Getting Started With Imaging
Hard to say as I'm still figuring out what settings work best for me but I'm typically playing around in Sharpcap with exposures around 1/60 or 1/125, I think (from memory), plus doing different combinations of exposure and gain. But mostly I'm looking at the histogram and going for something between approximately 30-70%. It might be that I need to crank up the frame rate and use more gain, but as I say, I'm still figuring this out. -
Inspire me about visual astronomy
imakebeer replied to imakebeer's topic in Getting Started With Observing
Wow! That really is mind-blowing! 🤯🤯🤯😲😲😁😁