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Everything posted by The Admiral
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Well, if it's a south facing window, wouldn't it be sensible to point the scope down to avoid it catching sunlight? I'd complain if it was being used by looking through the wrong end . We'd booked a caravan holiday in Broad Haven with the kids and this happened very shortly before we went! I asked a petrol pump attendant where we'd stopped for petrol if it had affected visits to the area, and he said that it had. Ian
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Lovely image. I prefer the one with stars, they add context for me. What scopes are you using here please? Ian
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Thanks Dave, but what I meant is that the mount is now advertised as having "Latest Version with Improved Polar Alignment Adjustment" which I took to be an improved mechanical adjustment, as I know this is an area that was criticised in reviews. Is this not the case as far as you know? Ian
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Hmm, that doesn't sound good. Is this with the so-called improved polar alignment adjustment? Just out of interest (there's no way I could afford one ), have you found guiding to be problematic? Ian
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Thanks for the advice. I had heard that the Berlebach tripods were highly rated. As it happens, I ended up buying an iOptron mount at the beginning of lock-down 1.0 last year, and that came with a tripod. Actually, I think the weight is not much different to the Berlebachs. Ian
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I don't know how competent or flexible the stacking software is on the ASIair, but I would suggest that you get familiar with the way DSS works as a first stage, otherwise you won't know what you are missing! It is often useful to be able to stack using something called Kappa-Sigma clipping which is very useful in removing satellite trails. Does the ASIair offer this option? I suppose I tend to be a bit of a purist in that I'd rather have the original data on my PC than have it pre-baked by the capture software first. At least I can treat in my own way, and have the option to repeat any processing if I'm not happy. Also, you will need to take darks, dark flats, and flat exposures to work in to your calibration, which DSS (or other calibration/stacking software) uses. Ian
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I think you would be correct in taking one step at a time. I know that I might be castigated by the purists for what I am about to say, but I think it would be helpful to get some perspective on what you are trying to do, and not obsess about any particular piece of software. At least, not until you have had some practical experience of astro image processing. Rick has given you a broad outline of what steps the processing is about, so that is a good start. As said before, other than Pixinsight, Astro Pixel Processor, Maxim DL or AstroArt, (others?), no one piece of software can do it all, even those who use the complete set of PI tools still probably 'polish' their images in some different software. They all have their different paradigms, quirks and idiosyncracies, and each take some learning and familiarisation. Some have an impenetrable manual, or perhaps none! Or just don't suit your way of working. The fact is, it is a long road to acquire the 'art' of processing astro images, but you shouldn't let that put you off. But take it a bit at a time and develop your skills. You will learn what software fits your way of doing things. You can download much of the software with a free trial period which is very useful, but I recommend you getting some experience before doing that otherwise you will be all at sea when confronted by it. I couldn't get on with PI . In my own case I started using the free calibration and stacking software, DSS, though ultimately moved on to AstroArt to do that as it accepted my particular camera files without prior conversion. Also, have a look at Star Tools. Virtually all my processing to date has used it. It does the processing but not the calibration and stacking, is remarkably effective in getting a good looking image, and is quite cheap, but it does have an operating paradigm rather different to others and it may not suit. But, at least it would be a good cheap introduction. More akin to Photoshop is Affinity Photo, very powerful yet very sensibly priced, especially if you get it during one of their frequent offers. In my view there is no point in spending a fortune on software until you know what you want and what works for you. And you won't know that until you have a bit of experience. Good luck with your endeavors. Ian
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Free Astro Weather API?
The Admiral replied to DaveHKent's topic in Getting Started General Help and Advice
I'm not sure it will be worth it 😉. None of the sites are very accurate, and they often disagree with each other! Even disagree with the weather I've actually got 😀. Ian -
I think it'll be fine. In the dim and distant past I did some antenna plotting with a 6m high S@N Yagi, horizontal and with 10° up elevation. There was hardly any difference in the response plots. 10° up elevation Horizontal These response lobes are a result of the antenna picking up the direct wave and the wave reflected off the earth, an interference effect if you will. There appears to be a slight loss of forward gain. That's my understanding of it anyway. In reality I suspect that local obstructions will have a greater impact. My antenna is horizontal in the loft space, and goodness knows what response I'm getting . Ian
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Understanding GRAVES Meteor Events
The Admiral replied to PhotoGav's topic in Radio Astronomy and Spectroscopy
Good stuff! Thanks. Ian -
Understanding GRAVES Meteor Events
The Admiral replied to PhotoGav's topic in Radio Astronomy and Spectroscopy
From my primitive investigations explaining the traces does seem to be quite involved. There are a number of documents which I have referred to along the way, which you might find interesting. I'll list them at the end. I'm sure that you've heard this before, but the Graves transmitter beams in a Southerly direction from it location near Dijon at an altitude of between ~15° and ~40°. If the meteors detected are at around 100km high then this will give a distance of between 120km and 325km to its South, assuming simple line of sight. Something like this: On a map, this looks something like: The transmitter doesn't broadcast to the whole of the zone simultaneously, but switches cyclically between zones of azimuth. However, there has been some recent discussion on here about how it is possible for those in Scotland, for example, to be able to receive scatter traces even though they are beyond line of sight. As a result there has been some speculation that the antenna may also produce a 'backfire' beam which scatters off meteors nearer to home. The reflected frequency is Doppler shifted as a result of the moving meteor (head echo) and the ionized tail left behind. If my understanding is correct the meteor itself doesn't really slow down, but loses energy through ablation. So although it is easy to think of the Doppler shift is as a result of slowing down, as I originally did, but it is more complicated than that. Have a look at the following documents, which I hope will be of some interest, if you haven't already that is . Ian Detection_of_meteors_by_RADAR.pdf Graves-Echo-english.pdf Detecting Orbiting Objects.pdf Meteor Detection using SDR.pdf Radar Echoes from Space DK5EC.pdf Radio Doppler fromForward-Scatter Head Echoes.pdf -
Indeed, but not sure it's funny . Here's my place in Oxfordshire. It's been murky all day, and we've had quite a bit of fog of late too. Mind you, I can check three different forecast sites and they all predict something a bit different, and more often than not, bearing no relation to my actual conditions! As my garden faces South with little to the North, I'm a but stumped. You could take photos of the Moon of course . Ian
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Great Orion Nebula and Horsehead Nebula
The Admiral replied to __Spirit__'s topic in Imaging - Deep Sky
I'd be very proud if that was mine! Stunning. Ian -
It's a long while since I used mine, but I don't recall it losing location info. The problem with an in-built clock is that it might not be accurate enough and you'd need to keep resetting it. Without the GPS module I used to use https://time.is/ and use that to give me the accurate time. I've got the impression that accurate timing is important if you want accurate alignment. Ian
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A little. I bought mine at the beginning of summer so it hasn't been out much so far. The kit for guiding has just been delivered, so that'll be the next step when the weather obliges and I have some time (and I'll report on it then). Meanwhile, this may be of some help:- Generally impressed with it's quality, I'm sure that you'll enjoy using it. Ian
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Barnard 150 with the RASA and Esprit 150
The Admiral replied to gorann's topic in Imaging - Deep Sky
Oh Göran, please stop doing this! . Yet another lovely image you've produced there, it's frustrating to know that I'll never get anything that good! Seriously though, they are a joy to behold. There's something about images which reveal dark nebulæ in all their glory. Ian -
RASA 8 is back: Iris Nebula chased by some dark nebulosity
The Admiral replied to gorann's topic in Imaging - Deep Sky
Could it have got any better? Yes, clearly it can! I like the result too . Ian -
Going deep into the Pleiades with the RASA 8
The Admiral replied to gorann's topic in Imaging - Deep Sky
That RASA is certainly delivering Göran, when in capable hands of course . The revealed striations in the dust are incredible. I wonder if such depth of detail could ever be revealed in less than dark skies? Ian -
RASA 8 is back: Iris Nebula chased by some dark nebulosity
The Admiral replied to gorann's topic in Imaging - Deep Sky
Groan! I'd rather not think about what is happening to this country. My blood pressure is raised enough already 😭. Ian -
RASA 8 is back: Iris Nebula chased by some dark nebulosity
The Admiral replied to gorann's topic in Imaging - Deep Sky
One can only dream! Ian