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Showing content with the highest reputation since 19/04/19 in Blog Entries

  1. 2 points
    Hi all Been a while since my last entry, so thought it about time to log another! Things are getting a lot busier at work. My area has changed, and I have now taken on Norfolk, along with Bristol and South Wales. I am a Regional Systems Manager for Greene King Pub Co. and look after all the sites IT and till equipment. So, more sites means more meetings and more miles, but I love it - getting out and about, and seeing areas of the country I haven't been too before. The other day I had to drive from Shrewsbury to Sheffield, and the SatNav took me over the Moors near Manchester, and the High Peaks near Buxton. It was a lovely drive!! As a result of the above, my leisure time has taken a bit of a hit, but I have still managed to get out with my Telescope on quite a few occasions, albeit from the back garden. When the weather has cooperated anyway! I will do a more detailed write up later, but I have made good in roads on my Lunar 100 challenge, and also made good progress in re-learning the sky. All being well, I will be heading up to the area around Ashbourne / Ilam in a few weeks. I have a friend living out in the sticks, and he has graciously let me use his back garden. Its proper dark there - compare to my garden anyway, so that’s something to look forward too. I have also taken my first, probably ill-advised step, into AP!!!!! I went out last night and took some pics of the full moon. I used my 25mm eyepiece, and hand held my iPhone up to it. I wasn't expecting anything amazing, but was fairly pleased with the results: Not completely in focus, but as I said, it was all hand held! Makes me think if I can mount the phone in some way, I could get some sharper shots. I have also found an old webcam - I have butchered it, and made some adaptions to allow it to attach to the focuser. I gave downloaded various software to hopefully allow me to get some video of the moon for stacking purposes. Not tried it yet, as I need to get a longer extension lead for the laptop. But I think it should work ok. I will do a full post on it once it has been for its first test drive!! Clear Skies!! Nige
  2. 1 point
    Perhaps the open outlook to the east Ensures the leaded panes catch every ray And part explains why on the dullest day My eye is drawn up to the colour feast, After a rubbish couple of months, finally a holiday........a week in the Yorkshire Dales, only a 7.5 hour drive from Kernow but worth it! A little cottage east of Hawes, nothing but sheep and pheasants and yes dark skies. Great food in small pubs with the friendly locals, Abbey ruins visited and gloriously recommended to sooth the soul and switch off the rat race (Easby Abbey nr. Richmond, Jarvaulx Abbey nr. Ripon), honestly THE best chips from The Chippie in Hawes and of course beautiful scenery! With not much room in the car (have to take the family not just the scopes?) I only packed the Heritage 100P and my BST eyepieces, opposite to my home viewing where I can only see the southern sky, here it was the West and North, typically for me the cottage had the only street light for at least 100 miles to the south.....still new things to spend time on........ So two clear nights.....once I got over the nervousness of total dark away from civilisation and wild animal noises I've never heard before....out with the little dob Auriga....the 3 open clusters, M36/37/38, even with a waxing moon, still was able to pull these out, have to say that the 12mm BST is turning out to be a particular favourite, reckon I could make out about a dozen of the brightest stars in the pinwheel cluster. Stars Capella and El Nath (start the Taurus debate here...) a lovely distraction....now if I hadn't taken the wife and son would I have seen the famous nebulae with my 8" Dob? On to Cassiopeia....and after the owl cluster.....and what a revelation. The first time viewing and frankly spent far too long staring at this beauty....actually think I could see it in my sleep that night! The whole constellation was a wonder confirming I need to be less lazy and get my scopes to local dark skies more often......just don't let work life get in the way Spent a fair bit of time viewing the moon, decent views with 5mm BST, and just staring up with my eyes at a dazzling dark sky full with stars. All in all a wonderful week, great days out, dark and clear skies at night, great food (and drink), if you get the chance, pack away some clean undies and a scope and head to the Yorkshire Dales (If you're interested...opening lines are from a poem called east window by Alan Hartley relating to a stained glass window in Leyburn)
  3. 1 point
    Recently had some bad personal news so did what I usually do in these circumstances.....I bought a new scope To be precise a Synscan 127mm Maksutov from Rother Valley Optics (no planned advert but have to say great service) At last clear skies tonight so set up my new scope, used 2 star alignment, Regulas and Sirius as my garden is only any good towards the south (street lights everywhere else), really simple, five minutes and up and running. Quick tour using handset for messiers and whipped through M46, M47, M48 and M50, followed by the Christmas tree cluster and the beehive With 25mm and 15mm eyepieces I have to say the Mak was a revelation, great views and a fun evening Looking forward to some great nights with this little treasure
  4. 1 point
    It's a question that comes up regularly, but what is the difference between a Barlow and a telecentric amplifier (TA), otherwise known as a Powermate, ES Focal Extender. Meade Telextender, Bresser SA Barlow, etc? A telecentric amplifier does give a 2x magnification, just like a Barlow but that's where the similarity ends. A Barlow is a negative doublet (Smyth lens) that causes the exiting light rays to diverge and hence deliver the image amplification. If you move the EP further from the Barlow the magnification increases, whilst taking the Barlow nose-piece off and screwing it onto the EP will [generally] give 1.6x magnification, assuming we're talking a 2x Barlow. In the FE/Powermate/TE/SA Barlow (the latter isn't a Barlow, which is a confusion) the negative doublet is followed by a positive doublet that turns the exiting rays back to parallel - ie, telecentric. Because the rays are parallel, the distance between the EP and the amplifier elements is [broadly] irrelevant as the image amplification was done internally, between the TA lens elements. In practice, this still means that the effective focal ratio of the scope is doubled - It's a common misconception that the EP focal length is halved - but unlike a Barlow, the eye relief of the EP in use is unaffected. In other words, you insert an ES FE in the scope and the EP behaves exactly as it did before and the scope has effectively doubled in focal length. The down side is that double the number of lens elements costs more, but whereas a Barlow (which has other uses because of what it does) tends to feel like a second-best-to-an-additional EP, the ES FE simply feels like you have an extra EP. In visual terms, it's a less intrusive and more transparent solution and a more transparent device. So the Barlow is second best? Well no, not all of the time. For the reason why, you only really have to look at Televue Naglers and the clones thereof. They weren't the first (contrary to popular forum lore, but they're certainly the most successful) to use the idea, but what Unc Al realized was that whilst it was easy(ish) to create a wide field EP, the difficulty was in creating them at shorter focal lengths with an eye relief usable by humans AND with a well corrected field of view, especially in fast scopes like large Newts. Essentially, what he did was create longer focal length wide field EPs and then fit them with a Smyth (Barlow) element in the nose. Thus, you got an EP that acted as a shorter effective focal length, but had greater eye relief than it would have without the Smyth element. Very cool. In fact, this is the source of the reason why Naglers (and there derivatives) are renowned as well corrected in fast scopes. The Smyth element does increase eye relief, but as per a Barlow, it effectively increases the focal length and therefore focal ratio of the scope. As we know, a slower scope is less prone to aberrations, but in this case, it's the EP that is effectively delivering it. Your Nagler is better corrected, because it effects a better correct scope. So, this is also what your Barlow can do. A 20mm EP in a Barlow (and TA) will give a better corrected view than a 10mm EP, all other things being equal. This is handy, especially if you like your Orthos and Plossls which tend to have ever shorter eye relief with decreasing focal length. A Barlow can be partnered with a longer FL EP to give an effective shorter FL EP, without the need to glue your eyeball to the EP it emulates. Whereas a TA uses up it's focal length in the focal path, a Barlow does the opposite and pushes the focal point outward - It adds optical path length. How is this handy? Well if you have a binoviewer that uses up 110mm+ of focal path, the scope (refractors in particular) may not have enough space available to rack the focuser inward to compensate. A Barlow, or at lest the doublet element from the nose of it, screwed into the Binoviewer is enough to push the focal point outward and get you that focus point back. That's just one example. The important point is that whilst a TA is, as long as it has room to work, a generally superior device, there are times when a Barlow has qualities all of it's own. A good example of both will be a one off purchase and both will deserve space in your EP case. Buy right first time and you may find they remain a constant, whilst your prized EPs come and go..... Russell
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