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Dave S

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Everything posted by Dave S

  1. Five years ago whilst observing the annual Perseid meteor shower I was seeing the usual trails coming from the radiant point when one was just a bright flash with no observable trail. Almost simultaneously there was a click coming from the roof of my house behind me. I'm fairly convinced that it was a grain of sand sized meteorite that made it down to hit the roof. Considering the substantial tonnage of matter that falls from space to the earth every day it doesn't surprise me that it probably was a micro meteorite. I just wish it would have been possible to have found it as that would have been a trophy to be proud of. Dave...
  2. @Coto I agree totally that a lot of cheap electronics can be less than perfect (usually a lot less) I try to source from reliable manufacturers. My preferred one is NooElec as I've used them on quite a few occations and find their products good quality and they have a support centre in the UK. The LNA I chose fits the bill for my needs as I'm not looking for huge signal gain and it doesn't have to perform perfectly to justify the £12 spent. There are Radio Amateur equipment suppliers that will stock quality LNA's in narrower bandwidths but we're now talking expense. The bandpass filter is wise addition as my experience with the RTL-SDR dongles is that certain powerful local signals can clamp down the front end of the receiver causing a sudden drop in the signals you are monitoring. I've been recently working 137MHz but a local pager transmitter running in the 140MHz area periodically kills the signal strength of the frequencies I'm using. It's not a big problem as I think the Interference needs to be within a few MHz. The RTL-SDR dongles have a bandspread of 2-3MHZ so they can continuously display that range. That's probably too narrow for other type of interferece to be a problem. I'm not suggesting that they will work for your needs but lo cost solutions will always have limitations in it's results but at the low cost it's well worth a try. If you're working 432MHZ at high gain and sensitivity be aware that there's a whole host of devices operating at around 433MHz. These include car key fobs, baby monitors, home weather stations and cursedly no licence required walky talkies. 433 is the low power unlicensed device mini band. Please post your progress as I would love to see how it goes. Cheers Dave...
  3. Hi Coto Does it need to be centred at 422Mhz? I use Wideband LNA's which run from about 1MHz - 2GHz They are very cheap ( I just ordered another from Amazon this evening). I depends on whether your receiver is nice and selective or suffers from strong local interference from other frequencies. I assume that you have a dish setup for narrow area reception and as you are pointing skyward then a wideband should be ok so long as your connecters and feerder cable are good. I've been experimenting with software defined radio and home brew antennas to receive and decode images from the NOAA satellites. This is the one I've just ordered. https://www.amazon.co.uk/0-1-2000MHz-Broadband-Amplifier-Radio-Module/dp/B076631WKC/ref=sr_1_6?ie=UTF8&qid=1548625234&sr=8-6&keywords=lna Dave...
  4. Oops missed the obvious. I've just finished a ten hour shift at work so the brain isn't fully operational. Here in the UK first light optics are a trusted favourite and they ship internationally. They even have currency conversion on the website. I don't know what the shipping costs are as they are calculated at checkout. They do the absolute all in bundle for £269gbp which even includes counterweights and dovetail L bracket. https://www.firstlightoptics.com/skywatcher-star-adventurer/skywatcher-star-adventurer-astronomy-bundle.html I don't know of any European suppliers so I don't have any comparable prices.
  5. They're both quite similar in specs but the star adventurer has a quoted payload of 5kg compared to the ioptrons 3kg. The ioptrons is a smaller and lighter mount but both are quite portable. The star adventurer comes with the ball head mount as standard whereas the ioptrons is an optional extra. An equitorial wedge is available for the star adventurer for a measly £45. Finally the biggest difference is the price. Star adventurer £195 Skytracker £350 Both have excellent reviews. Only my personal choice, but I'd be going for the star adventurer plus wedge for £240 all in. No doubt there are fans of both here on sgl so would be interesting to hear their take on it. Dave...
  6. No they have a standard power socket which the standard lead available from just about all astro suppliers fits. http://www.rothervalleyoptics.co.uk/rother-valley-optics-power-cables.html Other suppliers are available. Dave...
  7. A lovely example of where diffraction spikes enhance the image not detract from it.
  8. The three washers glued to the patio so I can locate the tripod precisely and start from the home position and get set up and aligned quickly. A close second is my cat. Great lap warmer. She doesn't like it as a dew shield though. ?
  9. What davey-t means is that the st4 port on the camera connects directly to the st4 port on the mount. No usb to serial required. The usb on the camera then connects to usb on the pc so PhD can see the guide star selected. Daft question but you do have a guide scope and camera in addition to your main scope? It's not clear what setup you have. Dave...
  10. +1 BackyardNikon Changed the whole game when I started using BackyardEOS. Dave...
  11. I'd say more than seems. For that money I could replace my mount scope and camera with some quality items.
  12. I suppose as an integrated system it's a sound idea. They state it uses the Sony imx224 sensor which is the sensor used in the gpcam2. If you have a scope already then £190 will get you a gpcam then just add laptop. As stated it is an amalgamation of existing technologies rather than a new system. Still quite nifty looking if you don't want the hassle of a laptop in tow.
  13. Check your insurance. You may need to specify individual items due to their value. Don't forget continental mains leads. Dave...
  14. And Rother Valley Optics on your doorstep. Nice!!
  15. I too use a canon (550d) with my preferred lens being a Tamron 55-200mm f4/5.4 and I use an alt/az goto mount for speed (particularly considering the current weather) If the lens is way off focus then I also get doughnuts. focusing a dslr lens can be tricky but using it in conjunction with BackyardEOS and a little practice it's not too difficult to obtain focus. I love the combination of the canon and it's lenses and there are some great widefield targets that a dslr can capture. With my alt/az mount I can consistently achieve 30-60sec subs which for me is fine for the brighter widefield targets. I gather usually about 60 30-60sec subs and DSS seems to take care of the field rotation quite nicely. With your kit it's surprising how many objects there are available in the widefield arena. I've been doing widefield for a few years now and still find more to go for. The weather however is something that can't be controlled (worst luck). Dave...
  16. The Doughnut effect as stated by john is usually a focusing issue. It is common with catadioptric type of lenses/scopes such as SCT's and Maks which aren't properly in focus. Dave...
  17. A modified dslr has had the internal IR blocking filter removed so that it is more sensitive to the IR wavelengths that Hydrogen Alpha emissions produce. Without the modification it is difficult to get results when imaging nebula such as the rosette nebula where all the nice detail is centred around the wavelengths of light that your unmodified camera is unable to see. The downside is that it renders the camera unusable for daylight (terrestrial) photography unless you have a clip in IR blocking filter. Without the filter (which is easy to add/remove as it just clips in) daylight pictures will appear overly red in hue as it will record the IR reflected by day to day objects and register it as red in your images. Darks lights and flats are quite easy to get to grips with and become second nature as part of your imaging session. As you use a Nikon I would highly recommend having a look at BackyardNikon which is a camera control/imaging piece of software that makes imaging an absolute joy. I use BackyardEOS for my 550d and was well worth the £50 for the premium version. https://www.otelescope.com/store/category/4-backyardnikon/ There's probably a primer on DSS somewhere on this forum. Dave...
  18. Do plenty of daylight setting up practice. It's amazing how invisible nuts/bolts/cable connectors are as soon as it gets dark. As stated get a collimator. What camera/software are you intendind to use? Dave...
  19. I own a mak90 but I don't use it for imaging as it has way to long a focal length as is a huge f11.8 focal ratio. I got so frustrated with imaging by trying to use the DSLR on it. My mood improved the moment I mounted my canon with its stock lens directly on the mount. Many nebula are quite large so the mak will only show a fraction of it due to its large focal length. The weapons of choice currently seem to be the 130/150pds, sw80ed or the recent wozs61 which is incredibly small and light. APO's are more expensive than achromats because they use special glass and are ground to rediculously fine tolerances to prevent chromatic aberration where as achromatics aren't and so won't produce good images. Dave...
  20. Hi there. Your mak 127 weighs 5kg. Dave...
  21. This is a good one to consider at under £110. https://www.jessops.com/p/canon/ef-50mm-f-1-8-stm-lens-96690 Dave...
  22. Lovely scope but don't forget to factor in the £149 for the matching field flattener to get the best out of it. Dave...
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