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Uranium235

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Everything posted by Uranium235

  1. Yes, this was brought from new. Master flat is as follows (from a 135mm f2 Samyang):
  2. Again, it is with much regret that I'm in the position of having to sell another piece of my imaging gear. This time its the Atik 383L+ mono CCD camera, which has served me flawlessly for the past few years. Anyone who has seen the images Ive taken with this camera can be in no doubt as to its capability - and its happy on focal lengths from 135mm, all the way up to 1000mm. Additionally, it comes with the Artemis capture suite - which is about as simple and intuitive as it gets when it comes to "set up and go" imaging.... in fact, its so easy to use even a 5 year old can operate it (and did). No silly cable types required, just a USB cable and standard centre positive power lead (both supplied). There are three motes close to the sensor, but they always calibrate out perfectly. And there is a minor mark on the cover glass, but that is clear of the sensor - and never appears in either the Light or Flat frames (so its not an issue). Given the cost of servicing which is about £50, I will knock that off the initial cost. The bonus being that all Atik servicing is UK based, so you're not shipping it to the other side of the planet. But, as it stands its all ready to rock anyway if you use calibration frames (which you should do regardless!). Example images are as follows: So, what is the cost of greatness? £860 (includes £50 discount) UK Sale Only Payment method(s): Cash, bank transfer or Paypal (buyer pays fees). Delivery: Either collection or courier (buyer pays delivery costs) As usual, the price is the price, no discounts or haggling please - its cheap enough as it is already And if you're sitting on the fence considering whether you should be going with CMOS or CCD.... the CCD is the clear winner - hands down, no contest.
  3. Now sold, thanks to everyone who showed an interest
  4. I'd like to add that the item can also be couriered (for an additional tenner) - but that would be at risk to the buyer (I'd like it to arrive undamaged, but it would be well packaged).
  5. It is with much regret that I am being forced into selling off a fair portion of my astro gear - starting off with a fine example of what the Star 71 Mk1 should have been for everone who brought one. Its a telescope I would describe as competition standard, and indeed was good enough for me (and my son) to get shortlisted for the IAPY two years in a row - so its an instrument with provenance. And anyone who has followed my exploits with it will know just how good it is: It comes with its soft carry case, and M48 > EOS adaptor. Condition-wise, there are a couple of light scratches on the powder coat finish but that does not affect its worth or performance. The price? £650 The price is non-negotiable (no "best price" please... this isnt a car boot...lol). Either buyer collects, or I can deliver (within a sensible driving distance if buyer chips towards the fuel) Payment method(s): Cash, Bank transfer or Paypal (buyer pays fees). UK SALE ONLY This is your one chance to own it, make no bones about it... this telescope is irreplaceable.
  6. I believe there are one or two people who use that camera and lens combination quite successfully... though their names have slipped my mind for the moment Though I have to add, try not to go for the exact spacing of 44mm. Aim a little under that (43.5ish), that will ensure you avoid the hard infinity stop that lens has (some lenses can focus past infinity, but not that one).
  7. No FW, no room for one! I use the integrated 2" filter thread that is inside the bayonet > T2 adaptor. Bit of a pain to change filters, but it's solid and it works
  8. Thanks Sara yep there are a lot of possibilities for this one. It's just a case of which way do I go? I'll try going right (or south in this case) and see what that gets me. Fortunately I have spare data from all areas of Cygnus, so it wouldn't be too hard to perk up areas of interest.
  9. Cheers Harry Im still toying with the idea of turning it into a 3x3 to take in the NAN and go deeper into Cygnus - or if im feeling particularly brave... adding colour.
  10. It seems to have taken ages to put this one together, given other things that have been going on in the background (non-astro stuff). But this week Ive been able to add a couple more panels to make a 2x2 mosaic, though processing was tougher than expected due to the sheer volume of stars in the image. Dont try a star count with DSS... I tried it and it didnt like it...lol. Noteable areas of interest are the Flying Bat, IC1396 and the Cocoon (down in the bottom right corner) - which have been boosted with some Ha data from the Star71. Another unexpected issue was the amount of cropping I had to do because of sky curvature (must be a consequence of imaging near the zenith) - its definitely not down to camera rotataion becuase that is mechanically fixed. 25x240 (L) x4 panels Samyang 135mm @f2, Atik 383L+, NEQ6 Thanks for looking Fullsize: Here
  11. All booked now Friday and Saturday night. May extend, but that depends on a few things.
  12. Poster size projects arent just made up of one image - but a series of them all stitched together as a mosaic. So if you have a small chip, but need to cover a large object - just mosaic it. Bigger sensors with more (or more and larger) pixels produce a wider field of view if used on the same optics, and cuts down the need for mosaics. For instance, on the same optics - an camera with a resolution of 1040x960 is roughly A4 if printed out. While an APS-C type sensor or CCD like the 383L+ which has roughly 3300x2500 pixels (just smaller that APS-C) will produce an image that would just about print on A2. Going further than that, if you use the large sensor and mosaic it - you end up with images that if printed at pixel scale would easily fill an entire wall.
  13. It also depends on what CPU is in there and what OS you are using. If its the new generation of CPUs (ie: Ryzen), then it will not accept anything less than W10. You can get W7 on there, but its a major hassle to get it done (I gave up and went with W10, which turned out quite nicely). W10 Pro is dirt cheap, but I would advise you install it from a DVD as the the MS installer version is a bit hit and miss. You can download the image from MS and burn it to a DVD.
  14. Might be worth taking a look at the sensor charts then, so you can work out what might be the best ISO for you. https://www.sensorgen.info/ Dont worry about star colour at the moment (something which a high ISO will wipe out). Edit: just noticed the camera isnt listed on sensorgen, so you might need to do a bit of google pestering to see if anyone has performed tests on the sensor.
  15. I flocked mine (including the drawtube), made a cover for the bottom and use a flocked dewshield. Also I take flats with the dewshield in place and use a light source not too bright, and slightly backed off (a large monitor helps). Also helps to diffuse the light a bit more with copier paper - epecially important if your monitor or other light source has a slightly reflective screen/cover.
  16. Im not sure you mentioned what camera you were using, in order to reduce the trailing in the raw images you need to drop your sub length a bit (or use guiding). If youre using a CMOS based camera you can increase the gain in order to reduce camera noise and therefore make better use out of the reduced signal that comes of a consequence of using shorter subs. On top of that, get the focus a bit closer - then DSS should have no problem registering your subs correctly.
  17. Thanks Olly, things have been a bit sketchy for the last couple of months - there has been either loads getting in the way, or when Ive had a quiet night ive been just too hot and bothered to set it all up. I'll be glad to see the back of this particular Summer! A couple of weeks is fine, but two months of blazing hot weather.... not my cup of tea (especially when trying to build a patio).
  18. Top left: m16 Top centre: m17 Top right (ish): saggitarius star cloud
  19. Its been a bit difficult to set up for the past month or so due to the back garden resembling a building site. So last week I got a skip and cleared away the rubble, but even then I had no opportunity to set up late enough in the evening... But, finally, last night I got out for a quick session to stop me from going rusty Again, the Samyang performed flawlessly - especially now that ive removed all play from the bayonet connection and tweaked the lens>sensor distance. The corner stars are pretty much perfect at f2. So, just an hour in 5min subs. Unfortunately, my new house does not have the southern view my old place did - so this is as low as I can go without going to a dark site... which im considering for next weekend if the weather holds up. 12x300 (Ha) Samyang 135mm @f2, Atik 383L+, NEQ6 Thanks for looking
  20. Might be worth waiting til the winter Grant it's a bit scorchio at the moment (even for a cooled camera!)
  21. Anything in Cygnus is good! If I was in your position, I'd be looking to use the fastest oprics I have at this time of year so you can make the most of the short nights. I'd probably go for the Canon f2.8, but not their 135mm (the Canon 135 is a now-ancient design, and not too great in the corners). And as im sure youre aware, its all about the corners!
  22. Thanks I think the S71/383L image had the edge due to the focal length and larger pixels. Though if given a 2nd stab at the rosette I could probably improve upon the results being as that image was pretty much the first image I got out of it.
  23. ZWO ASI178MM Cool Review: This experiment/review came about after some discussion about whether images taken with small pixels and short focal lengths really do work out to be similar (in the resolution of detail) to images taken with larger pixels and a longer focal length - given that the aperture used was capable of the required sampling rate. So, with that question in mind - the ASI178MM Cool piqued my interest as to whether it could compete with my Atik 383L+ in terms of a viable imaging platform - not just for random pleasure imaging, but also for serious competition standard images that will stand up to the most demanding pixel peepers. With a huge thank-you to Grant, I've been able to put it to the test and hopefully answer a few questions for those who might be considering whether tiny pixels really can produce a passable astro image. This is my first ever review, so I hope what I cant get across in words, would more than made up for by the images. So, a few days later the camera arrived - and here is what I found in the box: ASI178MM Cool (obviously!) in a nice protective soft case 1x USB3 cable (rather sturdy looking) 2x USB ribbon cables (short) for connection from ASI USB hub to guide camera (nice touch!) 1x Nosepiece 1x paper instruction manual 1x mini DVD with drivers, sofware and manual To my surprise the existing nosepiece of the camera (that terminates in a female M42 thread) can be removed to reveal a short M42 male thread (that can just go straight into any 1.25" filter wheel). This means the backfocus distance to the CMOS chip is a mere 2.5mm according to the mechanical drawing. This leaves any potential user with tons of options for using filter wheels or an OAG etc.. not that the setup needs an OAG due to the short nature of the exposures we are going to be using. Driver and software installation: Fairly straightforward, just click on the installers found on the disk and windows will pick it up without issue. For reference, the imaging notebook I was using for the test runs on Windows XP. Sharpcap is on the disk, I installed it - though I didnt quite take an instant liking to the user interface (being a user of Artemis for 8 years). Therefore I went to the more familiar MaximDL for camera control and capture, setting the gain/offset function for the camera via the ASCOM control panel. Being as this was a test camera, no firmware or driver updates were applied. Running straight out of the box. Camera Spec: Pixel size: 2.4 microns Resolution: 3072x2048 (6.2 MP) FWC: 15k Bit depth: 14 bit Peak QE: 84% Weight: 400g Fairly tempting figures there, 15k FWC isnt disasterous as its roughly 2/3rds of the 383L+, and enough pixels to make decent image size when viewed at 100% (in theory). Another thing of note is that while the sensor size is quite small, that can be offset to some degree by selecting optics with a short enough focal length. The advantage of the small sensor size is that it will not overly test the corrected field of your optics, which is good news for those who like to build mosaics. The first test had to be with the Star71 as I was still awaiting delivery of the new f2 lens. However, the camera isnt a good match for the Star71 since its apeture and focal length meant that the camera would be oversampling what resolution the optics were capable of by a factor of 0.3" p/p. So with that in mind, any potential buyer will need to check whether their short FL instument has enough apeture to give a low enough dawes/rayleigh figure. Test #1: ASI178MM + Star71 Imaging resolution: 1.41" p/p Conditions: Poor Settings: Max dynamic range Subject: Rosette (Ha) Exposure: 4x300s Not the best night to be out, with quite a lot of cloud dodging so only a few of the captured subs were useable. So, I concentrated on matching 3x300 from the ASI with one 1x900 from the Atik. One minor issue I had at this stage was difficulty calibrating out the starburst-type amp glow you get with this chip (more on that later). Whether its a result of the oversampling, or the small pixels, or the conditions - but the stacked image looked a little "softer" than the single 383 sub. But given the state of the sky, it wasnt really a fair run to be honest, as nothing ever goes smoothly first time! So, the results were inconclusive. Test 2 ASI178MM + Samyang 135mm @f2 (narrowband): Now with the Samyang 135mm firmly in my posession, I constructed a compact and lightweight imaging rig - hilariously undermounted on the NEQ6. I set it up this way - using the ZWO tripod collar on the lens (padded out with some felt), and the guidescope ring - rather than have the lens dangling off the camera. That is because the lens is at least twice the weight of the camera, and that would put too much strain on the bayonet connection. Remember, we are at f2 - so any compression of the weakest link (the bayonet) would be punished severely in regard to field flatness. Ideally, the camera needs to be supported as well, so there is no strain anywhere along the imaging train. At 135mm f2, the resolution achieved was now in the much more familiar territory of 3.6" p/p - only slightly (theoretically) lower than what I achieve with the 383 + Star71. As a bonus, the sky was particulary good that night. Conditions: Good Settings: Unity gain Subject: Rosette (Ha) Exposure: 36x180s A quick inspection of the data revealed it was good enough for stacking, so the following night I took some calibration frames (dark, flat, bias, dark flat) that I could apply to the data using my usual method of DSS. However, as I found again - the starburst was still not calibrating out. Eventually, I settled on Maxim again to bail me out with its calibration routine - which to my relief calibrated out the starburst and any residual bias noise perfectly! There is probably a way to make DSS calibrate correctly with that data, but time was of the essence for this test so I needed something that just "works". From there I could stack as normal, then pop it into Photoshop for development. The data responds slightly differently on inital processing, taking at least two more curves to bring out the initial detail (when compared to CCD data). What became apparent quite quickly was the amount of detail that had been revealed by the camera and lens combination - which was quite surprising, and better than some telescope based images Ive seen over the years. It responded well to high pass and local contrast (as well as it could for just 90min!). The noise in the raw data is different to that of a CCD, not as consistent - but easily dealt with using a light touch of Ps NR (preserve details = 85%). As you can see, not bad for a small setup and short exposures! Now lets compare that with 90min of data from the 383 + Star71 (6x900) - a setup costing almost three times more: Now thats interesting, the ASI178 and 135mm while not delivering tighter stars - seems to a have caught almost just as much of the outlying nebulosity - despite the short exposures. Both images have noise, but it is different. As explained earlier, the CCD noise looks more distrubted, predicatable and repeatable - while the CMOS noise is slightly more random, especially between each calibration sub... which takes me to the next point. Once the ASI data is stretched a little more to reach into the background, what became apparent is that there was a small issue with the dark frame calibration. What seems to have happened is that pixels have been rejected that were good (ie: not hot pixels), which left a smattering of black dots across the image. Not noticeable at first glance, but they become more apparent once the image is pixel peeped. Nomally, with a CCD I would just ignore darks and stack the hot pixels out. But with CMOS technology, darks are an absolute must in order to remove the amp glow - so its a bit of a catch-22 situation. On further reading of topics regarding this, it seems that this (and some similar) CMOS sensors have variable dark frame noise from one session to the next due the the ambient temperatue - and the indirect way that particular sensor temperature is measured. Which may account for why the master dark didnt match the hot pixels present in the L frames - as my darks were taken indoors. This effect could be reduced or eliminated with a combination of dithering, a greater weight of subs (both light and dark), and dark frames taken in the same session as the lights. Though that last point could prove to be the most inconvenient in you dont have an observatory - especially if you have to pack up in a hurry! Why not just remove the hot pixels from the darks? Well, there is a good reason for that - if you attempt to remove the hot pixels, it drastically changes the data and therefore it is no longer a well matched dark and renders it useless. However, this issue was largely countered in the next test!  Test #3: M81 + M82, M106 After some discussion with a fellow SGL member in regard to calibration files, I decided to set the camera up with a UV/IR filer and see if this tiny rig could bag any galaxies. Now, in broadand imaging - this camera is completely different being as we are not having to separate a weak target signal from the camera noise (as would be the case in narrowband). So therefore any camera noise is quite quickly swamped, but that does not exempt you from full calibration! If you want to get into faint background signals - you need to calibrate.... no excuses! This time I took a set of darks at the end of the session (more on that in a moment), then followed it up with flats and bias. The reason why I left it until the end is becuase the ambient temperature of the sensor and electronics will be at its lowest point - and therefore less hot pixels - with only the most stubborn, persistent ones remaining. The logic behind this is that if the camera is ran as cold as possible, in a cool environment - then only "repeatable" hot pixels remain. Once that master dark is subtracted from the image data, the only things that should remain are the more "random" hot pixel, and hots that have been generated by a higher ambient temperature (at the start of the session). This way, any hot pixels that remain will be stacked out, and the "black dot" issue will be much reduced (or eliminated). The following two images are comprised of 40x120 exposures, fully calibrated: For just 1hr 20min each, thats actually quite good! Though I would think it would require at least double that amount of data to take more noise out of the image (I like clean data!). But what was more surprising, was that when I heavily stretch the bodes image - traces of the IFN were clearly visible, very unexpected indeed! I do however have to add that the IFN traces were only visible because of full calibration, as without it the faint signals would be buried beneath fixed pattern noise and/or vignetting. This has led me to the conclusion that for narrowband, this camera needs to be set up differenly (perhaps lowest read noise setting) in order to make the most of the weak signals you are looking to detect. But for broadband, just set it to max dynamic range and give it some fast optics. Test #4: M101 + M51 Now, time to see what happens when you give this camera a telescope with a larger aperture (and hence more resolving power). The dawes limit for 130mm is 0.89" p/p, but with the 130 running a 0.9x corrector we will be oversampling at roughly 0.85" p/p. No real time to test the collimation of the 130pds, and quickly set up using the bayonet connectors I used for the Samyang 135 so the spacing was roughly 2.5mm too short. However, I was quite surprised at the results. 36x120s (UV/IR filter only): With more time on target it would improve sufficiently in order to reduce noise, and apply better sharpening and contrast enhancement. M51 - 20x120s (UV/IR filter only)  Quite a surprising result given the short exposure run, with some of the fainter outlying dust starting to show. However, the "black dots" issue returned in this image - but being as it was in the background (and not on the target) I was able cosmetically correct it by using photoshop to sample, then paste in the correct background level (with added fake noise) using blend mode lighten. This technique can be learnt here: http://bf-astro.com/backgndRepair.htm So, as you can see - tiny pixels can turn a rather modest telescope like the 130pds into a fairly good galaxy hoover! Test #6 - Needle Galaxy Now pushing it a step further to see what happens when I use 100+ subs on a target. Well, so unexpected was the result that it made Flickr "Explore" - which doesnt happen all that often! So its no mean feat. Also, a slight change in the imaging train as I decided to use the Baader MkIII corrector for better stars. 120 x 120s Also, its picked up a fair few background galaxies to boot. I'd go as far as to say its my best ever result on this particular target. I think perhaps its a case of "the more you use the camera, the better you get!". Conclusion: So, could this CMOS based camera do what CCD has done for me for the last 8 years? Well... its a close one to call, but at the moment - CCD still has the edge in narrowband imaging (my most used imaging mode) - mostly becuase the noise enitrely predictable and slow changing, the exposure length is unavoidably long, and I like big sensors. However, this review is purely based on the ability of the camera to image deep-sky objects. So when you take into account its flexibility as a planetary or solar imaging camera - then you have something quite rare... a jack-of-all-trades camera which wont break the bank. Indeed, if I were to point my 383L+ at the Moon or try Solar imaging - it would turn to me as if to say "What on Earth are you doing?!, Dont be daft!" Therefore, while not quite being a direct replacement of CCD technology for the (very) serious imager - it is however an excellent introduction to mono imaging - a place that (in my opinion) used to belong to the Atik 314L+. And made all the more tempting by the fact that this camera is half the (new) price of what would be considered an entry level CCD. So, if you're thinking of stepping up from DSLR, but cant afford or justify the best part of 2k for a CCD camera setup, then this camera is a good way forward as long as its paired with short focal length optics that suit the pixel size (making sure to check the dawes/rayleigh limit for your optics first). A good match for this camera would be a fast lens between 135-200mm in focal length (eg: Samyang 135 or Canon L series 200mm) for widefield, or for sub arc-second imaging - the Skywatcher 130pds for galaxies (barring M31 & M33). https://astronomy.tools/calculators/telescope_capabilities Pros: Makes for a lightweight, compact imaging system Sensitive Places fewer demands on the mount & guiding Quick to cool Fairly clean data (when properly calibrated) Built in USB hub Easy adjustment of camera settings At a price which is easily scalable (twin or triple shooter) Multiple applications (DSO, Solar and planetary) Ideal for the mobile imager that requires a lightweight, compact setup. Cons: (though minor) Requires suitable focal length and/or aperture Tricky dark frame calibration (since resolved - see test #3) High HDD storage & network (on data transfer) useage Paper instructions hard to read (even with glasses on) CMOS technology is definitely heading in the right direction - and its very, very close to catching CCD. Ideally, the next step for this technology should be the implementation of sCMOS, where a lot of the electronics have been taken off-sensor (amps etc..) - that would remove all amp glow and would (going by whats on paper) spell the end of the road for CCD. However, these sensors are still very new, and very expensive. Perhaps in 5-10 years time, one of them will end up inside an affordable astro imaging camera. As to whether the issue of the detail given by small pixels and short focal lengths being the same as a camera with larger pixels - on a telescope/lens with more focal length? Well... its close - the setup with a longer focal length and larger pixels still has the upper hand. But perhaps given a similar level of exposure to what you would put in with a CCD, that would provide a depth of data good enough to get in there quite agressively with whatever processing tools you have to hand. Lastly, while it might not be so fair as to compare one setup to another costing three times more - its definitely worth consideration for those on a tight budget or who already have the camera for planetary/solar, and fancy a go at some DSO work. 
  24. Exactly what I used for the job (Samyang 135 @f2). That way you can keep the subs short, and grab enough of them before moving East for the next panel. That way youre always shooting at roughly the same alt (and not guiding it into the ground!). The major factor at this time of year is the lack of proper darkness, so you have to plan your dates and make sure there is no hint of Moon hanging about. Oh, and watch out for Saturn (if going across to the galactic core) - it will give you a lens flare.... but nothing a bit of creative photoshopping wont sort out
  25. No narrowband required, if anything you need to work quickly against the rotation of the earth (if doing a mosaic) - so it's a dark site and just a UV/IR cut filter. It's very fleeting, so you can't hang about!
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