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About BiggarDigger

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    Star Forming

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  • Interests
    Astronomy (obviously!), IT (work - ugh), electronics and radio engineering, meteorology, fresh air and wide open spaces.
  • Location
    Biggar, Scotland
  1. Hi everyone, it's been a long time since I posted. Life in general has got in the way of stargazing this year. Family and very heavy work commitments plus a house move have combined to limit what I could do so far. However, the fires still burn and I recently stumbled upon a 9 month old "unused" used Flextube 300p on eBay for a very decent price. A colleague has been interested in buying my 200p dob for a while, so it seemed to good an opportunity to miss. The previous owner of the 300p was a complete newcommer and had bought too large for a first scope. I suspect it had been an impulse purchase and sadly, they became disillusioned with its size and gave up without ever using it. They had made quite a mess of the colimination. The secondary was way off, while the primary also need a fair bit of tweaking too. After an hour or so back and forth with both Cheshire and laser this afternoon it's not perfect, but it'll do for now. The rain and gales cleared tonight and clear skies beckoned. Our new house has pretty extreme light polution with an LED street light no more than 15 feet from the back fence shining directly into the garden. The light is so strong and harsh to be painful to look at and there are no dark corners to hide in, so the backgarden is now really limited now to test sessions such as this. I've scouted a few darker locations nearby and they seem to be pretty good with my old 8 inch dob, but tonight, with a new scope, I wanted to be close to home in case I needed a hand or had forgot something. So, by 9pm I was outside with a combination of 27, 18 and 12mm Starguider EP's and an observing hood to try cutout glare. I use a Wixey look-alike digital angle gauge and that seemed to work fine on the new beast. M31 was much brighter than in the 200p. Unfortunately M34 was not visible due to light pouring into the tube from the street light. The double cluster in Perseus was awesome despite external washing of light. Mars showed surface features, but was in fact almost painful to observe with diffraction spikes and a bit of turbulence making it difficult to observe for a long period of time. Turn around and with the aid of the angle gauge pop straight onto the Dumbell then over to the Ring nebula, both of which were much brighter and more defined than with the 8 inch tube. A hint of colour in M57 was visible even when looking north west towards the town. Plenty of other open and closed clusters came and went. Up to M81 and 82, bright and clearly defined. Spent a while just messing with the scope and getting used to it. The previous owner had removed thd 9x50 viewfinder and mounted a telrad base directly over the screw holes. That will need to be moved, as I use both telrad and 9x50 to navigate around, and with the severe light pollution in the backgarden now, it's very difficult to star hop with just the telrad. The scope is a heavy piece of kit, but not unmanageable. The base is a bit awkward being much heavier than the 200p, but it should be fine after getting used to it over a few sessions. For the ota, one hand on the bottom rim around the primary and the other around the lip between the two halves of the seems to give a good balance. One thing I was pleasantly surprised at is the addition of a lazy Susan bearing. It makes a tremendous difference compared to the Teflon bearings of the 200p. Overall I'm pretty pleased with the new acquisition. Next year I may retrofit a Nexus DSC to help with navigation, but for now it seems a great piece of kit. The darker sites nearby appear to be around bottle 4ish and it should excel there. Thirty minutes drive there are sites close to where we used to live: I can achieve bortle 3 which should be awesome with the 12 inch appeture. I have a week off at new moon in November, so keeping fingers crossed for a good session or two then. From the mid range weather forecast however, it does seem that a larger appeture attracts more clouds! Stay safe and well everyone. Clear skies! Richard
  2. It's been a while since I managed a decent session under clear skies, but tonight was another opportunity to experience a wow moment! The Clear Outside app predicted clear skies from about 9pm, but I had to wait until 11:30pm tonight before the mid level cloud rolled back to leave unobstructed views. There was still a little murk now and then over Clyde Valley and seeing was a tad variable at times, but good enough I hoped to locate my quarry for the night. Virgo was well presented for my 200p dob. I popped in a 27mm Starguider and had a bit of fun around The Eyes and Markarin's Chain while my eyes fully dark adapted. After about 30 minutes of getting thoroughly lost in a sea of galaxies, I decide it was time. I had earlier looked up some finder charts and loaded Stellarium mobile on the phone. So, I headed south and lined up on the pair of 13 and 15-Vir, then started the dance of feint pin-pricks of light heading north by north-east. After several false starts and taking in time to be amazed at the intensely brilliant red hue of SS-Vir, I landed upon what I would describe as a skewed rhombic asterism comprising HD 108615, HD 108473 plus three others that I couldn't find a designation for. From there, I confirmed the location by looking at a curve of 4 feint stars slightly to the north of the asterism. Yep, I seemed to be on target. I took the right hand corner of the rhombus (furthest west in the sky) and nudged gently north until I found a second pair of feint mag 11 stars. Bisecting these was a third feint star, I'd estimate around mag 12. I stepped back for a few seconds to stretch my back and looked again through the eyepiece. Just to the north of the middle star lay my quarry. A pin prick of light, always present with averted vision and sometimes visible with direct. 3C-273! Only 2.4 Billion light years away! You may think it's a long way down the road to the chemist, but that's nothing to Space! (With apologies to Douglas Adams). I have to admit to having a big grin on my face. This iconic object visible in an 8 Inch dob from a rural back garden. Observing some more, it became more clearly defined with direct vision as time went by. It would be easy to brush it off as just another pin prick of light, but it's likely to be the most distant object I'll ever observe, and I bagged it on the first attempt (though it was pretty hard doing the initial star hopping). Reading up some more on the object and looking at the images on the web, really brings it home what an astounding object this is: emitting as much light as 100 Milky Way galaxies, the light taking 2.4 billion years to reach my eye and complete with a relativistic jet visible to Hubble and other professional observatories. Honestly, the famed Virgo galaxies are just down the road in comparison! Happy as Larry, I packed up to come in, dry off the 'scope and a pour myself a large glass of The Macallan. Stay safe and healthy everyone! Richard
  3. It is possible with an 8inch Newt. But, you have to have extremely dark skies, no light pollution, near perfect conditions including seeing, sky, time and patience. I observed it last Saturday 18th January from my garden under Bortle 3 skies with an 200p Dob. The seeing was as near perfect as I've experienced it. I've studied that part of the sky many times and had familiarized with what to look for. I'm afraid it's not an object that one can just turn up, point the scope and have any hope of seeing. The nebulosity that defines the HH was right on the limit of visibility and it took over an hour or more of dark adaption, preparation and exclusion of any external light sources. Line up on Alnitak. Check if you can see The Flame. If not, there's no chance of spotting the HH. If the Flame is bright, clear and you can see branches sticking out from the trunk of the Flame, follow its main trunk out to IC435, the bright star surrounded by nebulosity to the south east of Alnitak. Make sure Alnitak is out of the field of view else it will destroy your ability to see. From there look northwest to see if you can spot any very marginally lighter patch of sky. That will be IC434 and be very, very marginal. It should fill about half of the field of view and have a more or less straight line edge heading back towards Alnitak. Don't expect to see any fluctuations across the body of IC434, just a slight decrease in darkness compare to the background sky. If you can see that, breath deep, cover any sources of light and wait. After some time, you may be lucky enough to see a dark thumb appear in the vaguely lighter patch of sky adjacent to two mag 9 stars. Then again, you may not...I've tried many times and can say I've only observed it twice. I can't stress enough that you need no other light sources, very well adapted night vision, perfect seeing and transparency. Anything other than perfect conditions will result in a no-show. And prepare to be underwhelmed - it won't look anything like that you see above - just a dark patch in a dark-ish sky. With no moon around for a little while, if clouds clear in the next week, you might have a chance. Richard
  4. I'm very lucky to live under Bortle 3 skies about 3 miles outside of Biggar in the Southrrn Uplands of Scotland. NELM is difficult to be consistent. Some nights it's a soup of murk looking south over the Clyde Valley, other nights, such as last night NELM is at least 6, probably better. A lot depends on my neighbours too. Outside lights from the farm down the hill can be difficult some nights. A few weeks ago when I looked, Uranus was naked eye object. Last night Cassiopea was a sea of stars and there were so many stars in Orion's shield that I practically lost count. At least 11 that I did count, but quite a few extra came and went as averted vision tricked the mind into miscounting. Mrs Digger and I are hoping to move to be closer to family further north this year. Whether I have access to this kind sky in the future is unclear, but for now, when conditions are good here, they are really good.
  5. For various reasons, I've not been so active recently. So it was with great anticipation that I was able to get out with my trusty 200p Dob. Dark, crisp, clear & moonless skies awaited. Picked up on a few of my go to objects to check sky quality. An earlier squint through field binoculars suggested it should be good. An so it was. M31 and M33 looking good. Dust lanes in M31 visible over the extent of roughly three field of views. The lop-sided presentation of M33 mottled with brighter patches showing at least some of the star forming regions. Round and up to M1. Bright and well formed with a crisp edge to the south and a northern aspect that Douglas Adams and SlartyBartFast would have been proud of. Drop down to M42 - well, it would be rude not to. I can't get over how amazingly detailed this object is under clear skies. So now swing round to some more challenging objects in and around Ursa Major. Even though they are bright, I always find it quite difficult to align on M81 and M82. Once found however, they are good jumping off points for lots of feint fuzzies. From M81/82 its just a nudge down to NGC3077, then back up to NGC2976. From there west to NGC2985 and NGC3147. I tried north for the IC520 group, but either they were too feint or my star hopping let me down as no sign could be detected. No bother, swing down to the top of Draco and pick up C3 just for good measure, then across to NGC 4125, which oddly enough is a new galaxy for me. Tried for NGC4605 but again my star hopping high in the northern skies let me down and no amount of scope hugging could get me on target. So I drifted down to somewhat easier declinations taking in M101 and M51. Spiral structure in M101 was clearly visible with the 27mm eyepiece and the two objects that make up M51 were amazing. I don't think I've seen M51 so clearly separated into the two components before, the interactions between the galaxies clearly visible with trails of material linking the two. Across to the southern edge of Ursa Major and locate M106 as a starting point, then up to NGC4147 (another new galaxy for me) and across to NGC3949, both of which were not much more than feint smudges. Tried east to NGC4138, but couldn't locate it, so up further to NGC3938, the third new galaxy for the evening. Having drunk my fill of fuzzies to the north, I swung back round to the South where Orion was appearing from behind the only (and most annoying) tall tree just beyond the boundary of our property. Line up on Alnitak. The Flame bright and clear with a central dark band and a couple of side fingers visible. Last winter I was able to just about observe the HorseHead, right at the limit of the capability of the scope and my eyes. Would it be cheeky to try for the Horse head again? It would certainly be a waste of these skies not to try... Move Alnitak out the the field of view, IC435 is bright and well defined. I guess the nebula itself is illuminated by a central star because the central point is so bright fading to wisps of nebulosity in a vaguely circular pattern. From last year, I recall there are to mag 9 stars that mark the eastern edge of B33. With IC435 to the east, beyond these two stars I can see a very slightly brighter patch of sky, IC434, to the north west (in the EP). Like last year, it oozed in and out of visibility. I pulled the snorkle hood of my winter coat up over my balaclava to shield any external light. Masked my left eye, but kept it open and breathed deeply for a while to allow oxygen to reach my eyes and brain. Sure enough there was a darker patch of sky about the same width as the distance between the two mag 9 stars. Very poorly defined with extreme difficulty discerning any edge at all, but definitely a darker patch in IC434. I stood up to stretch and went back to the eyepiece a few times. Each time this slightly darker finger was there with IC434 visible defining the darker patch that is B33. I have to say, that if I didn't know what to look for, I would have completely missed it, but it was a little easier than last winter. After 30 minutes trying a H-Beta filter and coming to the conclusion that it made visibility more difficult. It was a cheap eBay knock off, so maybe there's a flaw in it?. A 10mm unfiltered EP made IC435 and the Flame stand out better, but introduced instability in seeing, so for me on that occasion the unfiltered 27mm was the best. After a while, despite thermals and winter clothing, I began to feel the cold: ice had long since formed on the OTA and my homemade Telrad heater wasn't able to keep the viewfinder clear. However, Leo was up! I quickly took in the triplet, but unfortunately tiredness was setting in and it was just too cold to wait for Virgo, so I packed up just before midnight and came in after three hours of glorious skies. A night to remember. Richard
  6. The chart tallies with my anecdotal experience. We live quite close to the brown blob in Southern Scotland and it does feel like it's been a bit drier than normal. We're about 220m asl in Upper Clydesdale and the river is low for the time of year. Yet my daughter at university in Aberdeen, complains about getting soaked through on her recent field trips. Youth eh? I have a feeling the winter will make up for it - it usually does, and there is an active weather system due in a couple of days. What's notable however, is the brown areas are uplands: Lakeland, Southern Uplands and NW Highlands, so, drier than normal may be somewhat relative. It's also notable that we haven't yet had an autumnal storm yet. Been quite calm generally. I think there's a met office weather warning issued for later this week, so maybe things are about to change?
  7. -7C here. Too cold for me. Retreated inside 45 minutes ago. Bagged some new galaxies mind, so that's ok.
  8. The list is of aircraft navigation beacons, in that specific case in Greece. The beacons are used for radio direction finding using carrier phase modulation as far as I can recall. They radiate carrier signals that will scatter from incoming meteor strikes int eh same way as the GRAVES Space Radar transmitter, but since there are many more and they are closer to you than GRAVES, you have much better chance of receiving signals. Being lower in frequency the signals will scatter and propagate better than at 143MHz too. I wouldn't discount GRAVES - it's a very high power space radar illuminating the sky in your direction, but it's a long way and the signals will be weak. These aircraft beacons may provide a better option. However, I don't know where you are in Greece, so the list may not be of much use by itself. You want to be a minimum of 400km away from the transmitter, ideally more. Perhaps a better source my be on the island of Cyprus, Lebanon, Israel or even Egypt, or to the north west in Hungary, Czech Repubilc, Slovakia, Austria, or Switzerland. Balkan countries at a closer range. For example, here's the list on that site for Austria: https://worldaerodata.com/nav/Austria.php ,Cyprus: https://worldaerodata.com/nav/Cyprus.php and Italy: https://worldaerodata.com/nav/Italy.php Tune the the carrier frequency, point the antenna in that direction and see what you get. If you are close to the transmitter (say <1000km) you may need to arrange some elevation on the antenna so that you are receiving signals from the common volume of sky at 90km altitude. I'm afraid I don't know how to check which are active. Perhaps someone else here may know, or failing that maybe look on the web for resources. You should also be looking for beacons that radiate reasonably high power - but my guess is that most will do that anyway. Richard
  9. The LNA will help, but I suspect you'll also need a directional antenna if attempting this with the GRAVES Radar. Since you'll be close to maximum range for meteor scatter, the signal will be very weak. The LNA will help with that, but a directional antenna will reject local noise sources making detection much easier. FM radio stations are typically wideband to give better audio bandwidth and fidelity (greater modulation index). Meteor reflections of such signals will be phase and frequency shifted and making automated detection rather more difficult I suspect. This list of navigational beacons in Greece may give a different option: http://worldaerodata.com/nav/Greece.php With many beacons being only 10Mhz or so from FM radio stations, you may not need to adjust the hardware too much. The Leonids shower peaks tonight, so is a guaranteed source or incoming meteors to test different configurations.
  10. A quick look on the web this evening finds this resource http://radiomap.eu/ which may help identify suitable VHF FM stations. However, I recall now that there was some discussion a few months ago in this forum about using aircraft navigation beacons as the transmitter source. These might be a better option if only because its unlikely that there would be interference from a transmitter local to the receiver. It's also likely that a aircraft navigation beacon radiation pattern would be better suited than that of FM radio transmitters too. Whichever route is taken, elevation of the antenna may be necessary to illuminate a common volume at approximately 90km. A bit of simple arithmetic should give you an estimate of the ideal angle, but I wouldn't loose too much sleep over the accuracy because the 3dB beamwidth will be quite wide, so an approximation should be good enough. Good luck! Richard
  11. A quick reply before work. I'll try add more detail later if I can. For the FM transmitter route, try to find a station at least 300km distant (ideally more). From a meteor scatter perspective, it doesn't matter which direction the station is, but if it is behind mountains signals will be reduced and if in the direction of a large nearby city a lot of noise will be present. You should look for a transmitter with no other stations on the same frequency nearby which will mask the return echoes. I should think there should be lists of stations, frequencies and locations somewhere on the web. For this geometry, you would need to point the antenna in the direction of the transmitter or close to it. I imagine you would need a lot more gain on the antenna too, but the advantage of the FM transmitter is that they are often radiating high power reducing the gain required at the receiver. Richard
  12. There is certainly the possibility of receiving signals from GRAVES in Greece. However, there may be real world limitations that make it very difficult. Many years ago, I ran a system of 4 stacked and bayed yagi antennae on the 144Mhz amateur band. The array was as large as domestic garage mounted on top of a lattice tower. Not something the average meteor observer might be interested in. I was successful in many long distance contacts up to and exceeding 2000km on both meteor scatter and Sporadic E propagation, plus successful moonbounce contacts too. On occasion I made contact with radio amateurs in Greece from central England by 144MHz Sporadic E, so it can be done. Using forward scatter, the maximum range for meteor scatter is around 2200km. If both the transmitter and receiving stations are illuminating the sky on their horizon such a distance is achievable. However there is the likelihood that the main lobe from the GRAVES radar is elevated by several degrees, moving the common volume towards the transmitter site. Also, in order to receive signals at these ranges, high gain antennae and low noise receiver systems are required. At these frequencies, low noise can be achieved reasonably easily, but high gain antennae are, as noted, very large and cumbersome. You can use a more local VHF FM transmitter, but it needs to be out of groundwave range, say at least 300-400km distant and return scattered signals may be swamped by local stations operating close to the distant transmitter frequency In is possible to build a meteor radar system yourself, but there are again practical issues to consider. You would need a radio licence (probably a radio amateur licence would suffice). You could setup a distant transmitter, remote controlled over the internet and listen for scattered echoes at the receiving station. Don't underestimate the transmit power and antenna gains required though. A time multiplexed radar with 100% modulated carried where you listen for echoes in the gaps between transmission such as in primary radar systems would result in very significant sideband noise, be very unwelcome to any other spectrum users nearby and likely be shut down by the authorities quite quickly, so a remote transmitter is really the only option. Even then leaving a strong carrier radiating on an amateur band 24/7 is also likely to be unwelcome. The cost of suitable receivers and a modest antenna is not great and there are a couple of very prolific showers coming up over the next couple of months. I would be tempted to erect an antenna, say a 15 element yagi, fixed at your horizon pointing at GRAVES. Equip it with a low noise mast head pre-amplifier, very low loss co-ax feed plus suitable receiver and see what you get from the Geminids shower in December. Richard
  13. That is a very good question, which I cannot answer with certainty, but I think there is a real world effect. It's possible that some of the effects seen could be artefacts of the FFT. Also, some of the bifurcation may be frequency scattering. However from the traces I've seen there are a number that I cannot explain. Here's a better one: I've seen traces wher bifurcated returns appear from nowhere after the start of an echo, or extend on after the "primary" carrier frequency echo drops into the noise. GRAVES trasnmits a carrier wave, so the scatter returns should closely approximate to a carrier wave, such as this one: The vertical "ticks" on the second traces correlate to and are assumed to be artefacts of the 2-second azimuth switching of the GRAVES radar. The wideband noise occurs at the switching points and may be further artefacts of the FFT, or saturation of the SDR. I don't recall seeing many of these artefacts on bifurcated returns. I do have even better examples of bifurcation which clearly shows two or even three traces in the time domain. If I can find them, I'll post. My guess on your superb echoes, is that that they represent the modulation of the TV signal, possibly coupled with some bifurcation too. Richard
  14. If receiving a TV transmitter, you'll also have modulation on the signal too. Even though the TV signals are amplitude modulated, I suspect when viewed on the waterfall plot you'll be something similar to the charts presented in both time and frequency domains. However, 55Mhz scatters better than 143MHz, so is likely that you'll also be seeing more effects from some of the rather strange bifurcations that can occur. I've seen such effects from the 143MHz carrier wave transmitter of the GRAVES Radar in France and have only come across one paper describing them. If I recall, the author was hypothesising that the cause is due to high altitude wind shear. They are difficult to find in my data, so this example is by far not the best, but gives an example of the bifurcation that you may be seeing. Richard
  15. Well, what can I say? Maybe I just got lucky using an inexpensive SDR, an inexpensive feeder and a simple small 2 element antenna from 1000km away from the radar? However, I've recorded 910 meteor pings today and counting.... Let me clarify for a moment: The less expensive SDR's are definitely not a match for the performance of the Funcube or other high end SDR's. The differences compared to the high end devices include lower dynamic range, lower sensitivity, poorer frequency stability, smaller RF and IF bandwidths and less flexible interface. These are measurable differences. However, my SDR (the one I linked to above) has performed meteor detection admirably a full year, with the only loss of signal due to my own finger trouble, poorly implemented Windows updates and holidays. Perhaps I miss a few scattered signals, but I have a limited common volume due to my range anyway. Perhaps my peak signal to noise is not as high as it could be, but 50db SNR is pretty big on the larger returns. Perhaps the device drifts a few Hz with diurnal variability, but a heatsink attached to the case adds to thermal stability. Perhaps if I wanted to look at the Hydrogen line or Band II signals, I might need better RF bandwidth, but I'm content with the 143MHZ GRAVES Radar. In summary, it's entirely possible there are cheap SDR's that are poorly built, poorly designed and poorly implemented, but I have had no issues with mine, save that the driver will not communicate with Spectrum Lab, but a free third party tool overcame that. £20 for a toe in the water? Got to be worth a shot. Then if the bug bites, or if higher performance is required, perhaps flog it on eBay and invest in a high performance device. You pays you money and all that.... Richard
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