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Hallingskies

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Everything posted by Hallingskies

  1. Suits an EQ6 tripod or equivalent. There is some scope (no pun intended) for adjustment, maybe out to 120 cm leg span. I used to keep my astro-imaging set-up permanently on it and just wheeled it all out of my garage, absolutely ideal. Nice big pneumatic tyres smooth the bumps out. Trolley weighs about 20 kg so collection would be best. £80, cash on collection.
  2. We actually didn't feel too badly disposed towards Thanet's finest at the time, despite their initial brusque approach. They have a tough job and had probably had a bad shift. After a little bit of explaining (10 kids, a few parents and a teacher in tow gives you quite a good alibi - as well as back-up) they backed off and were actually quite interested in the constellation tour I was doing! We were about five miles from Manston airport and a few weeks or so after 9/11 so sensitivities were probably quite high, but I still think it's best not to use laser pointers in public even if there are no planes about. Nut jobs have given them a bad name, to the point where anyone seen using one is automatically assumed to be causing mischief, at least on this side of the pond. PS: Just noticed you are Texas-based, Louis. There is a world of difference between US and UK policing styles, I think, sorry for any misunderstanding!
  3. Sorry mate, but I was in a field with a teacher friend and some of his kids when a couple of HM constabulary rocked up, aggressively demanded to know what I thought I was doing and tried to insist I hand over the pointer I was using. I said nothing about them seeing it - I assume someone else saw us and phoned them. Spin on your own axis if you like, just sharing my experience....
  4. From personal experience I would not use a laser pointer. The use of laser pointers in the UK is not illegal but you will find that your local police will just assume that you are a moron and will give you a hard time if you are seen. And given that the majority of the Great English Public do seem to be pretty moronic these days, who can blame them?
  5. +1 for Pegasus hub. Not cheap by any means but reduces cables off mount to one data and one power. Dew heater and focusser control as well. Have had one for a year and don’t know how I managed without it. Actually, that last bit’s not true. I had a rats nest that kept getting snagged or had cables disconnecting every time I moved the mount. So definitely worth thinking about the Pegasus or equivalent if you have the budget. Oh, my mount is an NEQ6 by the way. I would also be rather jealous of your CEM60 (super bit of kit - and I’m sure the earlier “bragging” comment was in jest, which is how I read it, anyway) but I’ve just picked up an Avalon Linear second-hand....
  6. Looks really good, though I went the whole hog and got the Pegasus ultimate hub that looks after the USBs and focus control as well. Touch wood, it’s all worked very well so far... Just make sure you keep the power leads, particularly the dew heaters, away from the data cables as far as you can. I did suffer from what seemed to be a bit of interference pick-up on my camera (noise came and went with the dew heater cutting in and out on the auto-control provided by the hub. Problem solved by moving and shortening dew heater lead).
  7. I use an old version of Paint Shop (v7) but if it helps anyone, I've made a few notes on the "workflow" I used for this image here...
  8. The only time I have ever seen Zodiacal light was in NZ. Wonder if that natural sky glow is what’s showing up here?
  9. Unfortunately I use a very old (v7) version of PSP that bears little comparison to the new one. One day I will have to get to grips with it. I believe many of the tools in PSP are similar to those in Adobe however, so I would point you at Steve Richards’s “Black Art” book available from FLO. In terms of “workflow” my own limited experience suggests every target is different: tricks that work for some don’t work for others because of differences in star density, contrast and colour. I normally just do stuff until I get a result I like. I keep telling myself I should write things down as l often get a good result and then can’t replicate it!
  10. Haze = noise, no doubt. I even posted a “show us your subs” thread because of a run of really noisy subs, which then magically cleared in our recent run of clear skies. I thought I had a dodgy camera, but it just turned out to be dodgy skies.
  11. Olly: Thanks for the suggestions, which were spot on. They were rather obvious errors - I think I had been looking at the screen for too long! I have now fixed the weird blobby corners (you were right - I had used the "clarify" tool in PSP on the Ha layer, which was a bit of a sledgehammer for upping the contrast. It didn't actually need it as all it did really was blow the corners out...) and added a slight Guassian blur to the stars to soften them up. It definitely all looks better for it. Rather than clutter the forum with iterations of the same thing, I've just updated the image I posted in my blog if you (or anyone else) are interested.
  12. Olly: thanks - you are right, the central stars are a bit hard now I look at them. Nothing a bit of selective gaussian blur can’t fix. See what you mean about the corners, think there may be something in the RGB stack. Will have another play. I think one lesson I am learning is that you shouldn’t spend too much time working on the same image - you start not seeing your own self-inflicted artifacts after a while. Fresh eyes really help. My crummy suburban skies (and achromatic optics) should really limit me to narrowband but I’ve never been comfortable with the associated colour pallets - they seem so artificial. Nonsense, of course, because all astro colours are fake, really, but I keep coming back to HaRGB (with a bit of Olll thrown in occasionally) because nebulae “look right” in them, to me, anyway. Still, if B****t drives me abroad then maybe it’ll be to somewhere with good skies...
  13. Oh right, thanks. I’m self-taught as no-one has ever written anything up for PSP (maybe I should) but I normally adjust my background in each channel to about the same neutral level (15:15:15) using curves - so that sounds like same thing! I found it took out the weird green blobs I used to get in dark backgrounds. Old versions of photoshop are like hen’s teeth (and renting it is a rip-off) and I care not for the jargon that goes with PI. Over the years I’ve found PSP can do most things that Steve Richards now spells out in his excellent book. I wonder who else is out there using PSP?
  14. Sorry, I don't use Pixinsight, like I said. I kno knothing about zis "background extraction". Sounds painful...
  15. Equipment: ATIK 460EX, Vixen 114mm f5.3 ED114 refractor, NEQ6 mount, guiding with Lodestar X2/PHD Subframes: 36 x 300s H-alpha, 15 x 200s each for RGB (2x2 binned), flats for H-alpha (same ones rescaled and used on RGB, seemed to work!), hot pixel removal in Astroart (no darks). My take on the Rosette, processed in Astroart/PaintShop Pro. Eventually. I wanted to keep the dusty stuff as dark as possible and to retain the contrasty nebula detail. I was surprised at how large a brightness range the object had, particularly in Ha. Did think about grabbing some OIII but I think images of this with a bright blue core look weird, so I stuck with what I got over the last two clear nights (in a row! Clear tonight as well but was home too late to feel like setting it all going - I'll regret being lazy tomorrow). Just wondered how other non-Pixinsight users blend Ha with RGB data.
  16. I can't see what the problems are here. It looks great to me. But then I'm not a PixInsight-powered pixel peeper...
  17. I was out for a walk in the sunshine and also thought there were more about than usual, enough so as to make me take a pic. Must be quite still up there...
  18. I think your best bet might be a Pulsar dome with a self-build housing. I remember seeing a cracking-looking obbo built along those lines in a recent thread on here. I think Pulsar also do different colours if the stark white is a problem.
  19. Thanks. I fully understand that “stretching” an image brings up noise as well as signal. It’s one of the first things I got to understand when I started astroimaging about 15 years ago. What I don’t know is a way to measure or express a signal to noise ratio in a way that would allow consistent assessment of the noise in any given image. I realise the example I posted here is a bad one: IC 443 is a faint object even on a 600s sub, so the act of making it visible on a single shot will always bring up noise - it’s why we stack subs of course. But how can you objectively assess noise levels in individual subframes? How would you know if the background noise you see in any single sub is “natural” e.g. from haze or light pollution, or if it is down to some sort of camera fault? Would darks or flats always address the latter if it the problem was of a random, non-uniform nature, e.g. electrical interference?
  20. First of all, this is a pretty spiffy first attempt. There's loads of good data there and low noise overall. In terms of colour balance I had a bit of a quick play in good ol' PaintShop (I don't do Adobe). It's your image and I don't believe in posting other folk's data (and I'm nowhere near as good a processing whiz as other folk here) but I found that 1) dropping the overall saturation a bit and 2) bending the low end of the blue curve a bit (Paintshop version attached) gave me a slightly more colour-balanced picture. You will be able to do the same things in Photoshop I'm sure. Have a play - you are very close to what I think is a very good image.
  21. You are right, of course - I use Astroart and that applies an auto-stretch to displayed images. An unstretched image is very dark, as you say. It is hard to compare background noise levels between images without (literally) a level playing field. Unfortunately I have no idea what you mean by "single PI histogramtransform stretch to the first vertical line." Looking at my sub histograms though, there isn't any junk to left of the main "cliff" however - when I've had REALLY noisy images, there's loads of fuzzy stuff there. Don't know enough about the theory to know if the two are related, however...
  22. Thanks. Just seen your wider field shot on the imaging forum - very good indeed! On the subs front, looks like mine are not as bad as I thought l from what I've seen above. I run my camera, filter wheel and dew heaters through a hub on the scope and I was wondering if the rat's nest of cabling was inducing some electrical interference that the camera was picking up.
  23. Looks like my version (also taken last night) is a bit more stretched than yours. When I tweak your version in PSP it looks about the same as mine wrt "graininess". It'll be interesting to see if anyone "experienced" replies... The final effort didn't come out too bad with only 16 Ha subs (plus some RGB for the stars).
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