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discardedastro

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About discardedastro

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  1. Okay - so, first things first! The big screw is to set the overall position (front to back of the tube) and allow for rotation of the secondary holder with respect to the focuser. Rotation isn't critical, but try and get the secondary mirror aligned centrally through the cheshire and get it looking "round" - a good way to easily see the edges and get contrast is to put something bright like a sheet of paper opposite the focuser in the tube so the secondary is silhouetted. The little screws are there to adjust tilt of the secondary once it's roughly in place, and this is one of the only really really important things - you need to get the mirror pointing at the centre of the primary. If those screws are completely loose then they might well have fallen out of their threads, and from the amount of movement you're getting it sounds likely, so the trick is to rotate and position the mirror holder so you can get those little screws engaged with the threads again. You might have to tighten the big screw to bring the holder back - the small screws won't protrude very far. If you have a small mirror and torch you should be able to look down the side of the mirror holder (in the "gap" between holder and vane centre). Once you've got 'em re-engaged you should be able to crack on. http://www.astro-baby.com/astrobaby/help/collimation-guide-newtonian-reflector/ has some great tips on how to use a cheshire to do your collimation.
  2. Baader LRGB is pretty damn good for the money, pretty equivalent to the Astronomik from what I've seen.
  3. So, first things first - can you achieve any sort of focus? Take the scope outside in the day and, *carefully avoiding the sun*, point it at a distant (and I mean reasonably distant) object like the top of a power pylon or tree. You should be able to get the telescope in focus or at least close. If not, you've probably got an issue with alignment of the optics (primary/secondary) or the focal distance of your eyepiece requiring an extension tube. Without knowing more about the scope model, hard to say. You will probably also note that the finder doesn't actually point that close to where your scope is pointing - this is fine, and why those three little knobs exist around the finderscope, so you can adjust the finder to match the scope view. Doing this in daylight is a great deal easier. It may well be that your finder is sufficiently far off that you're just pointing the scope near the moon and not actually at it - it's easily done with small scopes and narrow fields of view!
  4. After the comments on my previous attempt... I figured it'd be worth reprocessing the data with a bit more care and patience, to see what I could achieve. I took a lot more care in blink/subframeselector, combined some 300s and 60s luminance subs to generate a HDR composite for luminance, deconvolved that (poorly, I think, but it's not abysmal - having all sorts of fun trying to avoid regularization issues, and you can see some artefacts in the core/arms despite masking), and combined with my RGB stacks. Photometric colour calibration, SCNR, MLT denoising, TGV, histograms, LRGB combination, a little saturation tweaking, local histogram equalization, and unsharp mask to finish. Quite happy that I've managed to sharpen up and improve the detail in the arms/core a bit, but still not 100% happy with the deconvolution result. There's also some issues in the top left/bottom right corners where the two nights of data overlap with different rotation. I considered mixing in the reasonable Ha stack I managed but it's also rotated thusly so was struggling to incorporate it in a way that looked at all natural, so left it out. I think any further improvement will require more data - here's hoping the weather calms down a bit next week!
  5. I hadn't really fully considered the SLR approach, if I'm honest, but it might make a lot of sense for the imaging half of the equation as I'm only thinking about wide-field. I've been pondering a new camera for terrestrial use anyway (looking at the Nikon Z6) so could expand/make better use of the budget overall in that sense, and I've got the big scope for Ha, so OSC without modification/cooling would be fine; would just need to pick out a decent lens/scope. An SLR would be easier to lug about than the ASI with all the supporting bits and pieces it needs, so there's a lot to be said for that! To be honest though even if I stuck to the ASI183MM as a camera, going down the "camera tracking mount" route looks to be more sensible than going full-blown APO on small mount, instead going for a very small APO like the WO z61 I could sling on a Star Adventurer or with a simple camera lens rather than a scope. The iOptron SmartEQ Pro+ looks like it'd work out about the same or thereabouts as a SA+tripod and be a bit more flexible; that plus a z61 weighs in around £820 which is a bit over spec but not a million miles away. Not sure about the SmartEQ vs the AZ GTI. I think I'd lean more towards imaging than visual - totally understand that optimising for one in a very tight set of requirements (weight, cost) is going to give a much better result than half-arsing both. 72mm f/6 would suggest the WO 73mm APO which is a fair bit dearer but agree it'd work well with the 183 for wide-field. Lots to think about - thanks all
  6. Hi all, While I add to the pile of cables and accessories on the 200PDS at home, I may end up with some days soon where I have to commute down south and overnight before I head back home. While I can get a hotel or B&B no problem the thought did occur to me that if I'm just overnighting for the sake of breaking up my driving, and since I'll be within 20-30 minutes of some fantastic dark sky reserves, I could just as easily find a campsite and pitch a tent for the night. But having lobbed my EQ6-R and 200PDS in the back of my car before (once was enough), I'm starting to consider what a low-cost second rig would look like for some wide-field AP and a bit of casual observing. So the spec is: Telescope, mount, tripod, dew shield, power Something that won't mind being carried around bumpy roads Total cost below £600-700 or so initially Not a Dobsonian/Newtonian I'd like a frac because I've already got the Newtonian side covered, and I'd like this to complement the Newt at home when I'm not out and about. Currently pondering some of the smaller WO APOs or the Startravel ED scopes, but the mount side of the equation is vexing me. I may just be being unrealistic about the cost, ultimately. What should I consider? I've also not done any "off grid" observation/imaging before - what else should I consider?
  7. I'll +1 the Petzls - I've been using a https://www.petzl.com/GB/en/Sport/PERFORMANCE-headlamps/REACTIK for a long while now and been very happy with it. It has a switchable white or red light mode with a simple button press, but it also has a sensor which adjusts the light output - this is very handy if you're nipping back indoors frequently as it basically turns out the light when you go somewhere brightly lit, and also dims if you're looking at a computer screen etc. Very comfortable to wear and the battery endurance is great. You can also adjust the light levels and reactive curves in software, which is rather nice. Bit pricier but they'll last decades.
  8. I'd always always always recommend avoiding extension leads wherever you can. Connectors introduce loss, and on longer cable runs you need to avoid loss to have cables perform as they should in terms of throughput and stability. Particularly if you're aiming for USB3 performance you can't go very far without running into trouble. USB hubs are actually great on longer runs, because they regenerate the signal, which means your loss tolerance effectively resets on that run. You can also get "active" USB cables that have mid-span regeneration but these tend to be quite expensive. I've had to use USB hubs to get even quite short USB3 runs into spec where the cabling was short but adjacent to power, Ethernet etc, even with ferrites!
  9. If we're talking the extension connector, rather than the connection into equipment... Five cable ties - one on each cable around the bottom of the cable strain relief, and then two looped through those, plus one over the mating point. This lets you create lateral tension without really hefty clamping or adhesives. Alternatively, form a loop so you can cable tie one cable to the other - you end up with one cable running back along the side of the connectors. This isn't quite as robust but will work pretty well in my experience. If you've got something to attach them to, then just putting a cable tie on each side through a rigid support behind the cable strain reliefs will work fine. Reusable cable ties will work if you need to disconnect anything; with some of these you can use velcro ties, but try it and see what inspires most confidence.
  10. This was a ASI183MM-PRO on my Skywatcher 200PDS, EQ6-R mount; Baader LRGB filters in a ZWO EFW with MPCC3 fronting the train. Guiding was a 120MC on a Primaluce 60mm scope. I did capture some Ha, but the guiding issues meant I was struggling with the longer exposures - I only ended up with a few usable frames.
  11. I can absolutely confirm the Pi camera isn't suitable. I thought "hey, I could make one with a spare Pi and a NoIR lying around!", went and bought a wide angle lens for the camera, made an enclosure, etc etc. Turns out the longest exposure the Pi will do is about 2 seconds. Even with the gain cranked to 11, it's useless. Absolutely go for a proper astro camera. I'd opt for resolution over sensitivity - I'd probably go for an ASI178MC or similar if I were aiming for a higher res than a 120MC, the QHY5 isn't a bad shout though. Haven't done one (successfully) myself yet, but will probably go for a 178MC attached to a Pi or similar - or get myself a better guide cam and recycle my 120MC into an all-sky cam. Really quite keen to try and train a deep neural network to do image analysis/segmentation so I can detect clouds, rain etc, more as a fun project than for obsy control. Edit: Attached is the absolute best I could get out of the Pi camera, post-processed in PixInsight. The starbursts on the right are amp or sensor noise of some form; the weird shapes top left are a sundial (and the glow is local skyglow).
  12. Definitely +1 to the comments of only going Ha if you can do long exposures - most targets will take a reasonable amount of exposure, especially if you're using your smaller scope. I'm in Bortle 2 skies and generally do fine with LRGB - but have considered a high transmissivity filter. We're mostly LED round here (starting to engage with the council on light pollution) which makes life a bit tricky.
  13. Not a lot of exposure time in this - only a few hours across a couple of nights, and was struggling with focus throughout - a Baader Steeltrack focuser and a Senso Sesto are on the shopping list! Threw out quite a few longer exposures due to guiding issues (turns out guide cameras can't see through a coating of dew very well - Lacerta deltaT heater controller has now arrived and been installed along with a Dew Zapper band, so that ought to help). Actually ran about half of this unguided; the EQ6-R does pretty well with a good polar alignment. Ran all this with Ekos using INDI on a laptop by the scope, which is working pretty well for control. One or two things I kind of miss from SGP, but nothing major. Still got quite a nice result out of this regardless, I think, albeit noisy and with a satellite trail I missed in preprocessing. I didn't do deconvolution - still really struggling to get PI to achieve a nice result without ringing, even using masks and star maps for local deringing. Hopefully will be able to improve on this!
  14. DirectShow requires a USB connected camera directly to your PC - fine for indoors, but not a whole lot of use if you want a remote camera pointing at the obsy from outside. For that I'd probably look at a USB CCTV camera type thing like https://amzn.to/2XEbGf3 or similar. But you're not likely to get PTZ on USB without bespoke software etc. The Dahua cameras are pretty well regarded and cost effective, eg https://www.aliexpress.com/store/product/IPC-HDW2231R-ZS-2MP-Starlight-IR-Eyeball-Network-Camera-2-7-13-5mm-varifocal-lens-IPC/1200032_32884384754.html?spm=2114.12010608.0.0.11743d8aLmrqrp - obviously think about focal length but they've got a whole load of different options including PTZ versions. They're all IP cameras, so you can get a h.264/h.265 video stream, MJPEG too depending on model. If you're just aiming to get that displayed on a monitor then you should be able to pick it up with VLC or any of the "standard" ONVIF-supporting CCTV management software packages out there. The PTZ control is likewise fairly standard. PTZ will cost more, though - even getting cheap cams from China you'll be looking at £250 minimum I think. Don't forget power over Ethernet or 12V power for your camera if you go this route.
  15. Yes, shorter/fewer L than R/G/B; still getting used to mono capture and learning the ropes. I did rush through the processing on this one, spent about an hour or so from calibration through to completion; I think I'll revisit it in future and try some longer luminance exposures!
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