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About juliangeorgeshaw

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    Puimichel, France
  1. Great image Andrew! Do you (or does anyone else) use the new Tak EDP flattener for the FSQ-85? https://www.takahashiuk.co.uk/Focal-Reducers/1399-/Takahashi-EDP-Flattener-for-FSQ85 What do you think of it? Julian
  2. Hi Louise I didn't mean to be a wet blanket . I meant to say that most Barlows are designed with visual use or planetary imaging in mind whereas the A-P Barlow (and in particular its dedicated extension tube) was designed by a DSO imager (Roland Christen). I think other Barlows would work optically but you might have to figure out a way to make the imaging train rigid enough for multi-minute, long focal length exposures. However note that even with a Barlow your 115mm APO's focal length won't be that long so it might work. As for the dark NZ skies, yes they certainly helped but, as Nigel's image proves, M104 is a bright object. I would try it and see. I only tried it myself because I admired Ignacio's images. Julian
  3. I had another look, this time on my on my iPad. Now the colour looks great. On my monitor (a Dell Ultrasharp) the halo surrounding the galaxy looks greenish and the rest of the image has a magenta-ish cast. So I take back what I said about the colour . I would still be tempted by a bit more sharpening (I know, typical rookie's error ).
  4. - Julian here. The integration time was about 7.5 hours total of which about 5 hours was luminance. - I tried processing the data myself (with PI) and made a hash of it. Olly very kindly offered to demonstrate what he could with the data and PS. As expected he's done a fantastic job, much better than I ever could and yet... And yet to my debauched PI-eyes it could be improved with a little less colour saturation and a bit more sharpening to bring up the pie crust . To my eyes it's a little soft. I'm still a newbie and this is just my opinion (and monitor), I'm sure others would say "natural" rather than "soft". (Don't worry Olly, no doubt my taste will mature .) - Imaging with a Barlow? This prompts the question: What's the point? Can a Barlow increase resolution? If not, why not simply take an image without the Barlow (and without all the problems of long focal length imaging) and blow it up? Of course a Barlow cannot increase the resolution *of a telescope*, resolution is limited by aperture. But we are talking about the resolution of the total system = scope + camera. Take a look at this from the Astro-Physics website (scroll down to Advanced Convertible Barlow): http://www.astro-physics.com/index.htm?products/products I took a few subs of the Sombrero without the Barlow and I seemed to get a similar but less pronounced improvement (A-P used an 8600 chipped camera [5.5micron pixels] and I was using an Atik 460EXM [4.54 microns]). - I think the improvement in resolution with the Barlow is real and/but it's due to the Barlow effectively shrinking the pixel size. (What does this say about the conventional sampling arguments which say that one should use big pixels for long focal length and that 0.41 arc secs/pixel is too small?). Or perhaps it's just that round stars simply look better than square stars even though both are false representations of what should be points of light? In any case I'm a believer in the A-P Barlow! - Could one get similar results with a different Barlow? I doubt it (though someone will prove me wrong ). Why? The challenge at 2.4m focal length with DSOs as targets is as much mechanical as optical. For an extra $50 I got the 2.7" diameter A-P extension tube into which one can screw the Barlow, so the Barlow only has to support its own weight. Conventional Barlows are long skinny things which must support the weight of the camera and filter wheel. This works famously well for planetary targets but it is asking for trouble with (relatively long-exposure) DSO targets. (In the attached photo, the Barlow is actually inside the tube labelled "A-P Advanced Barlow".) Note that the A-P Barlow does not claim to cover big chips. To cover chips you will need a mirror scope I think. But they are lots of trouble and I hate diffraction spikes . Pricy? $250 for the Barlow + $50 for the special extension tube + postage, customs & VAT is not cheap (esp. at post-Brexit vote exchange rates). But in my experience, unlike a lot of other kit, Astro-Physics kit always works (probably because the guy who makes it also uses it). - I had intended to OAG but my adapter was wrong ?so I used a little Borg 50mm guide scope with a screwed down fixed focus, mounted on the tube rings. (A-P's Roland Christen is a fan of guide scopes for refractors but is adamant they should be mounted either directly on the scope or using dedicated rings, not the scope rings. I tightened everything up and got away with it.) I used PHD2 for the guiding and a Mesu mount. (This was my NZ Mesu, I have another one in France. I had motor problems with both of them but now they are fixed, enfin, they both work very well ). - The light weight and high sensitivity of the Atik 460/EFW2 combination helped. (8600 chipped cameras *are* much less sensitive and IMO it does make a difference.) - 3 min subs at F15? Yes it's true. I am allergic to cooked cores so if I can see a core in a linear sub I reduce the exposure time. Also I don't like images in which the cores of stars are white and the the colour is only around the rim, I'd rather have the read noise. Finally I was conscious of the hazards of guiding at 2.4m with a piddly guide scope attached to the tube rings so I was inclined to keep the subs short. The Mesu worked fine at 2.4m, lesser mounts might not. But even it was affected by light to medium breezes (the scope is completely exposed and long-ish refractors are a difficult load). However 5 min subs probably would have worked too. In any case, as Nigel's excellent 30 sec subs image shows, M104 though small is very bright. Same applies many other deep sky objects. For example this is an image by the excellent and very helpful to me Argentine astro-imager , Ignacio Diaz Bobillo of another small bright object, Ghost of Jupiter using the A-P Barlow and a 130mm refractor (for a net focal length of 1640mm): http://www.pampaskies.com/gallery3/Deep-Space-Objects/Ghost-of-Jupiter2 Julian
  5. W-h-a-t d-i-d y-o-u s-a-y?? Yes it's W-I-N-D-Y here in Tekapo where I am trying to filch some more Kiwi photons. I almost got blown off the top of Mt John, home of NZ's famous observatory https://en.m.wikipedia.org/wiki/Mount_John_University_Observatory After days the wind has stopped but tonight it's cloudy When the sky is good here it's very, very good; I measured SQM 21.95 on the first night I got here. Thanks for the welcome. Incidentally I like your website which has great images but is more than just pretty pictures. I have noticed that the Kiwi astronomers I have met do serious astronomy, not just imaging....
  6. Wonderful image! Thank you so much for sharing your workflow and script. My PI processing is so muddled I can never remember what I did last time
  7. I'm back in wonderful New Zealand. With me I have my trusty Tak Baby Q (which was recommended to me by Olly Penrice and I've never regretted buying) and a second hand HEQ5 mount and tripod, the legs of which I trimmed by about 10cm so that it would fit in a suitcase. The HEQ5 and tripod in the suitcase with the handset and some wires etc. weighs in at just under 23kg. This is crucial since the China Southern Airlines baggage allowance is 2x23kg bags (most other airlines do not limit the number of bags but the total of their weights must be less than 30kg). The counterweights were too heavy to bring, I bought new ones in NZ. [ Yes I would LOVE to have taken an Avalon M-Uno instead; lighter, no counterweights and no meridian flip. http://www.iankingimaging.com/show_product.php?id=1252 But £4,000 is more than I paid for my Mesu! ] I said goodbye to the extraordinarily helpful John Drummond in Gisborne on the North Island and headed for the South Island. (John runs Possum Observatory, he is the president of the Gisborne Astronomical Society and he is a Vice President of the Royal New Zealand Astronomical Society. Best of all he runs GAS Juniors, an astronomy club for kids which made me an Honorary Member for giving them a little talk about my astro adventures in NZ. Best award I ever got . This is my gear set up at the Pacific Allure Heights B&B in Kaikoura which is about a third of the way down the east coast of the South Island of New Zealand. (Yes NZ really is beautiful !) http://www.pacificallure.co.nz/ full res: http://www.astrobin.com/220508/ The proprietors are not astronomical at all but, like all the Kiwis I have met, they were kind and helpful; they let me use their private balcony, they turned off the outside lights illuminating their sign and they let me drape my power extension down to my apartment on the ground floor. The sky was very good despite an isolated pesky street lamp, SQM 21.85 . In 4 nights I got 3 targets. Why didn't I pick targets more appropriate to my short focal length e.g. Eta Carina, the Tarantua Nebula, 47 Tucana etc? I can do them later, for now I like being a child in a toy store grabbing what catches my eye. My only criterion was that the targets could not be imaged well or at all in the Northern Hemisphere. My bible here is Chadwick and Cooper's Imaging the Southern Skies. http://www.amazon.co.uk/Imaging-Southern-Sky-Astronomers-Practical/dp/1461447496 I only wish they would identify more stars in their illustration to help centre the more obscure and fainter targets. I also recommend Pearls of the Southern Skies by Slotegraff and Willasch, a beautiful picture book which was too heavy to bring with me. http://www.amazon.co.uk/Pearls-Southern-Skies-Clusters-Galaxies/dp/1770854452/ref=sr_1_1?s=books&ie=UTF8&qid=1445176594&sr=1-1&keywords=pearls+of+the+southern+skies O'Meara's Deep Sky Companions: Southern Gems is interesting but because(?) it's for visual observers the illustrations are dire. So here are my images. Despite my short focal length I am (perhaps naively) impressed at the resolution 85mm of (refractive) aperture can achieve. Harry Page's videos were a huge help in extracting detail, especially the ones on HDRMultiscale Transform and Local Histogram Equalization. It's magical the way cores of clusters and galaxies which seem impenetrable open up using these processes when you get the right combination of parameters. But, as Harry says, one needs a lot of trial and error with those parameters. [iMO Harry's free videos are better than the expensive ones I bought. This is just my completely unsolicited opinion (I have never met Harry): I think it would be nice if people who find them helpful would sling Harry £10 or £20 to help pay for his bandwidth.] The thumbnails below are extremely compressed due to SGL's file size limitations so see the full res versions. Great Barred Spiral - NGC 1365 : I was very pleased when that little S shaped propeller in the centre emerged. Full res: http://www.astrobin.com/218700/ Blue Straggler cluster - NGC6397 : I used the Tak reducer for this because I love the dense star field in which it is immersed. In fact I think I like star fields more than some famous objects! With those PI processes I was able to get right into the core. Full res: http://www.astrobin.com/218702/ Golden Eye - NGC1291 = NGC1269 Is the colour off? Where are the blue stars? As I understand it PI can use either the average star colour or average galaxy color as a white reference. This is a neat trick but what if those averages are not white? There is a wonderful image of Golden Eye in Pearls of the Southern Sky but I don't have it with me to compare. Full res: http://www.astrobin.com/218703/B/ As previously, all comments, suggestions and criticisms welcome.
  8. Because I had a dangling USB cable and I was stupid my mount pulled the USB socket out of my Atik EFW2 filter wheel . To Atik's enormous credit they will replace the entire EFW2 circuit board for EUR 30.80 + shipping + VAT which is great service. But I don't want to do it again! Because this particular mount is a travel mount I can't tie everything down. One way to attack the problem is to have a USB hub which moves with the scope. Then you only have one USB cable from the scope to the PC to worry about (and one power cable from the scope to the power supply). The HiTec Hub Pro Ultimate saddle has a hub built in but it costs "around £700" and what do you do if the hub stops working? http://www.eastmidlandsstargazers.org.uk/topic/7305-hitech-astro-mount-hub-pro-ultimate/ My alternative is to attach this slim, light weight Anker hub, which only costs £10, to my telescope's dovetail plate with double sided tape; this is easy because the hub is so small and light. http://www.amazon.co.uk/gp/product/B00Y25XFGK?psc=1&redirect=true&ref_=oh_aui_search_detailpage Then I connected the camera, filter wheel and guidescope to the hub via short (0.5m) USB cables. I use these: http://www.amazon.co.uk/gp/product/B00FCK3AA0?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00 Finally I connect the hub to the PC via a good quality long USB cable to the PC. I use this 3m cable http://www.amazon.co.uk/gp/product/B008EQYRRY?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s01 and alternatively I use this 5m cable (because I left the first cable at home ) http://www.jaycar.co.nz/IT-Products/Connectivity/Cables-Leads/Active-USB-3-0-Extension-Lead-5m/p/XC4126 But is it reliable? I have used it a lot and so far never got the dreaded "failure to connect" message. Here is a picture showing the Tak baby Q with the Anker hub stuck to its dovetail on my HEQ5 travel mount. (The white patches are so that I know which way is "up" in the dark ). I haven't finalized the cable routing but even now it's not as messy as it looks...
  9. Olly I would be hugely flattered if you incorporated my data in your and Yves' fantastic image. Just let me know the best way to get it to you. (I am in NZ now with my mighty Baby Q which is best thing I ever bought which is thanks to your recommendation).
  10. This is a wonderful image. But I think there would be a lot more detail in The Squid if Olly had used a sensitive Sony chipped camera (and an Astrodon 3nm filter). (see the thread http://stargazerslounge.com/topic/246170-is-cmos-rather-than-ccd-the-future/page-4?hl=%2Bolly#entry2752941
  11. This is a great example Horwig, evidence always trumps assertions. To my eyes the top image is MUCH better. If, as I suspect, it's made with the Sony chipped camera it confirms that there really IS a trade off between the real estate of the Kodak chips and the sensitivity of the Sony chips (which is what one would expect comparing the sensitivity charts for the two chips). [if the two images are the other way around I will look a bit silly ] Is real estate king? Or is it sensitivity? It depends on your target doesn't it but for me it's sensitivity. The relatively modest extra real estate of the 8300 chip versus the Sony doesn't do much for me (albeit it would have given my M31 more breathing space). And Olly's magnificent ultra wide images are a bit beside the point because they use Kodak 11000 chips and need 2" filters (and you could buy a number of Atik 460s for the price of an 11000 chipped camera kitted out with Astrodon NB filters).
  12. The Squid? Did someone mention the Squid? Here is some evidence bearing on Olly's question (does the principal advantage imaging the Squid accrue from using a Sony chip or from using an Astrodon 3nm Oiii filter?) and Zakalwe's question (does the extra sensitivity of the Sony chip vs. the 6303 make a difference in general?): Nicholas Outters (the Squid's discoverer) used a Tak FSQ-106, Astrodon 3nm and 5nm Oii filters and an SBIG STL 6303 chipped camera. You can see his results in this document: http://www.outters.fr/images%20site%20astro/decouverte-OU4-eu.pdf For contrast my image is here: http://www.astrobin.com/203894/ I used a Tak FSQ-85, Astrodon 3nm Oiii filter and an Atik 460exm Sony chipped camera, binned 2x2 (so my 4.54 micrometre pixels are grouped as 9.1 micrometre arrays which is almost the same as the 6303's 9 micrometre pixels). I took 20x20 minute subs but I threw away about 5 or 6 of them. As Outters shows, the Astrodon 3nm filter does produce better results than the Astrodon 5nm filter with 8x30min subs. (By the way, this is consistent with the superiority of Sara's images using the Astrodon's much narrower band, NB filters images versus e.g. Baader NB filters which is what converted me to Astrodon. I am glad I paid extra for a 3nm Oii filter even though I did so with the intention of imaging in moonlight which doesn't really work, too noisy. IMO Astrodon NB filters are worth it, I only wish someone would make them cheaper). Then Outters uses 25x30 minute subs with the 3nm Astrodon filter and the 6303 chipped camera. IMO my naive attempt is much better than his even though I have less data and less aperture. So IMO the jury is in: using a Sony chip vs. the 6303 chip makes a big difference in favour of the Sony, at least on this target (the difference is certainly not due to the nut behind the camera, I am a newbie). As Zakalwe says there is a huge difference in the measured sensitivities of the two chips. I know that theory doesn't always translate into reality in Astro imaging but it would surprise me if the sensitivity didn't make a difference on at least some targets and I think the Squid is one of them. I do lust after the real estate of the 6303 but IMO the Squid is the most interesting object in the sky that I have come across so far (as a non-astronomer friend said it really does look like a squid. And to think that it is so large and yet was only discovered 4 years ago, by an amateur!). So for me "no squid = no deal" (I will happily sacrifice the Bat for a good Squid) but others may differ.
  13. You are right about Oiii. I bought Astrodon narrow band filters (even though they are so darn expensive) because of your images and I am glad I did, thank you Sara. They really are worth the money. But I also paid extra for the 3nm Oiii filter because someone (not you) said it can be used successfully in moonlight. That doesn't seem to be true in my experience. (It was in one of those OSC vs. mono posts; I do agree that mono is better but that claim was gilding the lily.) I also agree (in the south of France) with your rationale (in Spain) for switching from Atik to QSI; the cooling on the 460 is anemic, my set point is only -5 C to be sure I can hit it each evening. I can't make flats in the day time, it's too hot. But the 460 spec says deltaT=-25 so it wasn't mis-represented. Luckily it's relatively low noise...
  14. Kiwi astronomers are divided. Half of them think Omega Centauri is the best globular cluster and the other half think it's 47 Tucanae. M13 just doesn't rate! This is my image of Omega Centauri taken earlier this year with my trusty Tak Baby Q and an HEQ5 with cut down legs that I took with me by plane in two suitcases to New Zealand. (To save weight I bought new counterweights in NZ, mail order from NZ Telescopes in Timaru; recommended.) My subs were RGB using Astrodon filters, 9x360 sec each filter. (The subs were only 6 mins long on account of my modern, high sensitivity Atik 460ex camera and, possibly naively, I was afraid of burning out the core.) I started imaging at Stargazers B&B in Kuaotunu, on the Coromandel Peninsula of the North Island of New Zealand. I finished at a motel on the shores of Lake Taupo where they kindly turned off their floodlights illuminating the lake at 11 pm. (This is what Kiwis are like, really helpful people, the antithesis of jobsworths.) Stargazers is a luxurious B&B run by the charming Alastair and Harriet Brickell: http://www.stargazersbb.com/ This was my first attempt at imaging in NZ and I was afraid something wouldn't work. Alastair was very encouraging, he let me set up my gear beside his dome and he even lent me a cable at 3AM! Alastair is not an imager, he's a fanatical visual observer with a C14 in a big dome and he gives "astronomy tours" (they are included in the B&B or bookable separately). Now we have all been to astronomy outreach events and some of us have even given them. Clouds permitting people get a squiz at a few nice objects through a telescope which is great. But I have to say visitors often leave not having learned much about the universe. Not so with Alastair's tours. Perhaps it's because he's a geologist but he combines the requisite star gazing with a superb lecture with lots of Socratic questioning and huge collection of fascinating physical props in his study. It's quite long but it holds everyone's attention, a model for astronomy outreach. Hugely recommended if you ever get to NZ. Anyway, back to my image. As usual my processing is a Pixinsight muddle through, based on my interpretation of and varying ability to follow Harry's workflow. All comments/criticism welcome. Here are two comments/questions from me: a) If I play around with curves I can see an artefact that looks like roughly 0.5cm mesh netting across my image, especially in the vicinity of the core. Did it come from Local Histogram Equalization which seems useful though possibly too potent in my hands? Or something else? I would like to increase the saturation slightly to get more star colour but when I do I lose a bit of the core. What should I have done? http://www.astrobin.com/206346/
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