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Showing content with the highest reputation since 18/11/18 in Blog Entries

  1. 8 points
    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
  2. 8 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
  3. 7 points
    Hello there!! Yeah, its been a while since my last blog post. Work and family life have been unbelievably busy these past months – added to that the summer nights being short, things on the astro front have taken a bit of a hiatus. However, the nights are slowly drawing in now, and following our recent holiday to Cornwall I am slowly getting more time to get out under the stars! A couple of weeks ago, we took a family holiday to Cornwall. We stayed on a working farm, on the edge of Bodmin Moor. I had done some homework, and the farm had Bortle 4 skies, compared to my 6 at home in Derby!! I was looking forward to seeing some proper skies! The first few days, while warm and sunny, moved to cloud in the evenings. However, I got my chance on the Wednesday evening – clear skies from horizon to horizon! I waited for the sky to become fully dark, and went out into the little garden we had the use of at about 10:30pm. I was lucky – the farm didn’t have any floodlighting, and the only light was a security lamp on the farmhouse. I was well hidden from it anyway in the garden. I wasn’t able to take my 150pl with me (too big!!), but took my Celestron 20x80’s along. After my eyes became adjusted, I was rewarded with one of the clearest and brightest skies I had seen since my days living in rural North Norfolk! The Milky way was a bright band across the sky, with Saturn nestled in it toward the horizon, and so many stars I had trouble making out the constellations! M31 was bright and clear, and Double Cluster was amazing. I spent a good half hour just sweeping my bins along the star clouds of the Milkyway. It was then I decided to go and get my camera, and try and my hand at some basic AP. I set up my tripod and Canon 400D, set the ISO to 1600 and opened the lens to f2.8, and pointed it at Casseopia with a 30 second exposure (couldn’t do any longer than that as I had forgotten my cable release!). The image came back and even on the LCD I could see I had captured a lot of detail! I took a few more, and the results are below. Did some basic editing in CS-5 – just tried to make the detail stand out a little more. Am quiet happy with them – only 30 sec exposures! The lack of LP was a real bonus!! This has ignited my desire to take the AP further. Nothing like getting an expensive mount (yet!), but I plan to get the dual enhanced motors for my EQ3-2 and attach my camera to that. Hopefully I can get at least a couple of minutes exposures at moderate focal length. I only have a 17-55mm lens, but is the f2.8 version. I have also looked into getting an adaptor so I can attach older FD lenses to the 400D. There are some real bargains on Ebay for 135mm / 200mm and 300mm FD lenses. I will do a separate review of the place we stayed – it really is perfect if you are looking for base to explore Cornwall and Devon ,and also want dark skies at night!! Thanks for reading, and hopefully, it won’t be 6 months before I post again!! Cheers
  4. 6 points
    A belated Merry Christmas and a Happy New Year to everyone! I do hope everyone had a fantastic time over the holidays. Well, Santa has been very kind to me this year, and on Christmas morning I awoke to a huge box in the living room – it had been too big to wrap, and anyway I knew what I was getting lol!! So, I am now the proud owner of a Skywatcher Explorer 150PL. it was ordered from RVO at 4pm on Thursday afternoon, and arrived early on Saturday morning – great service!! I had um’d and ah’d for ages on what OTA to get, and I finally settled on the PL. To me, it seems to be a good compromise between focal length, portability and aperture. It will be perfect to get me back into observing once again. I think the mirrors will need collimating – that’s a given, right?? My daughter got me a collimating eyepiece and I have been reading up on how to do it – hopefully I can manage to do it without too many problems!! The tube has come with rings, dove tail bar, 10mm and 25mm eyepieces, a 2 x Barlow and a 30mm finder scope. I think I will be after a 90 degree finder at some point to make things a bit easier. I have mounted it onto my NEQ3-2 mount, and it balances ok. I think the mount it at is limit, but for observing it will be fine until I have saved for the HEQ5. Can’t wait to get it out under the stars, however, the weather forecast is cloud for the next week at least . . . sigh!! I guess that is the fabled curse of new scope owners everywhere!! So – lets hope that the clouds clear soon. I can see blue sky at the moment . . . just hoping it stays that way! Happy New Year everyone, and pop back again when the next entry will be following my first evening with the PL!! Cheers Nige
  5. 6 points
    It finally happened – after waiting two weeks and a day, the clouds parted, and I was greeted with a clear, still and cloudless sky!! Whoop Whoop!! 15 days is a long time to wait! The scope (SW Explorer 150-PL) had been sitting in my dining room since Christmas, and despite a very short outing last week, that lasted about 10 minutes, last night was the first time I used her properly. I popped the tube outside a good hour before I intended to go out to observe, giving it plenty of time to cool down. I then put the mount together – I did this inside, so I could see what I was doing! Once it was all secure and bolted together, I set the declination (?) to 53 degrees and took the whole thing outside through my patio doors. Before I popped the scope on the mount, I did a basic polar alignment. I was chuffed – I had the declination spot on, and just need a tweek to the left and it was there – not perfect, but enough for my first observing session. I then put the OTA onto the mount and secured it. I had been playing around with it in the house the previous week, and had found the balance point, and marked the dovetail bar, clever eh?! I then moved the counter weights about to get that balanced as well – it all worked out fine, and the lightest touch when the clutches were off was enough to move the scope about. I fitted the finder scope and got it aligned with tube – I did find this a bit tricky to start with, and a couple of times during the evening I managed to knock it out of true with my arm / head / face!! And I was now ready to go! My observing location is pretty limited at home – the front / side of the house is now flooded with light from an LED street lamp – the red circles show the street lamps, and the red cross is where I set up the scope. I had good views to the North and to the West though: I'm not shy to say that my knowledge of where things are in the night sky is limited!! This will change as the year progresses, so i content myself to first locate M31. I found this quite tricky - the finder scope is a straight through job, and the angles can sometimes make looking through it a challenge. So I bought out the 20 x 80's and quickly found it. I then pointed the scope in the same direction, and a few twists of the slo-mo controls and there it was. I had the 25mm eyepiece in and I realise that the target was waaaay bigger than the view through the eyepiece!! However, the core was revealed. I looked for quite some time, and small details began to come out and I'm sure I saw the darker dust lanes. I then took a look for the Double Cluster, and wow!!! What seemed to be hundreds of stars, packed into the view! I was getting happier by the minute! I content myself to just scan the star fields in that area for a while, and then swung around to try and and find M51. Using the 20x80 technique I found it, and turned the scope to it. It was a faint fuzzy at 48x, so I upped the mag to 120x with the 10mm eyepiece - it became a larger fuzzy object, and I couldn't really see any structure, but knowing the light coming into my eye had covered 20 million light years was awesome! It was getting late, so I took off the tube and carried it round to the garden with the street light over it - I wanted to look at M42 before I packed up. However, the glare from the street light overpowered the finder and I couldn't see anything. Tried to shield it with my hand, and although it stopped the glare, it was all a bit washed out. Shame - perhaps an air rifle would be a good investment . . . . . !! So, overall I thoroughly enjoyed my first night out with the 150PL. A few early observations on the scope and mount (this blog will be like a long term review for the scope): The OTA with tube rings and dovetail bar weighs in at 6.4kg / 14lb, according to my scales. This is right at the limit for the NEQ3-2 mount. Added to the weight, the tube is long at and although I got the balance spot on, it took several seconds for the vibrations to die down following focusing. However, using the slo-mo controls didn't induce any noticeable shaking when tracking objects, so thats a bonus! I think a heavier mount will be needed at some point. I hope to try and save for the HEQ5, but with daughter going off to uni in September that may be a while down the road!! The eyepieces and barlow that came with the scope appear to be fairly solid - I only really used the 25mm, and I have nothing to compare them too, but the view seemed bright and sharpe. The finder scope is a generic 6 x 30mm. While the view is crisp, trying to look through it gave me a cricked neck after a while!! A 90 degree finder will defo be required The dovetail bar is a lovely green colour, but does appear to be quite soft - just mounting the scope the few times I have used it as already left some marks and dints in it. The focuser is fine for my use - not stiff at all, and with enough friction to make small adjustments easy. I see no need to upgrade this yet. So - lets hope the weather stays clear, as I am keen to turn the scope on to the Moon!! Thanks for reading, and a Happy New Year to all!! Cheers Nige in Derby
  6. 4 points
    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)
  7. 4 points
    Invited by two of our children and grandchildren to meet them, early on Christmas morning, on the beach at Southwold for a swim. Had serious misgivings about this: as I dont do getting up early, I do not have a wet suit and recently have been under the weather. Anyway as my partner does have wet suit and was keen, a few bah-humbugs thrown in my general direction got me out of my 'toastie slumber chariot' before 8:00 UT and by 10:00 we were at the water's edge. There had been a hard frost overnight but by the time we entered the water, the air temperature was a balmy 2 deg C . I managed a brisk 2 minutes before I fully realised why in previous years I had restricted swimming in the North Sea to the months of June, July, August and September. Enjoy your Boxing Day Stargazers George thankfully no longer in the North Sea and in Lowestoft
  8. 3 points
    Hi all, Thanks for dropping into my blog – I have had over 9000 views in total now, which is incredible, so thanks all! As you will know if you have read the previous posts (dating back 4 years or so), I have very slowly been pulling together various bit and pieces of astro gear. Currently I have the following: Skywatcher EQ3-2 mount (white, non-motorised) – second hand for £90 off ABS Skywatcher 150PL OTA – new from RVO for about £180 25mm, 10mm eyepieces and 2 x Barlow (came with scope) Cheshire collimating device – new from RVO for £25 Celestron 20x80 bins – new from RVO for £99 Old Dell Laptop – Downloaded all the free software I can find for it. Free – old works one that wasn’t wanted. CMy trusty Canon 400D with EF-S 17-55mm f2.8 A dodgy old Webcam – this has been duly butchered and adapted to allow me to slot into the focuser. From the above, all but the Canon have been procured over the past 4 years, and only the OTA and Bins where purchased new. Going forward, anything I buy I will note how much I have spent. So, I have set myself a personal challenge!! I want to try and show AP can be done on a small modest set up like this! Up till now, its been purely visual that I have been doing. However, alongside that I have decided to dip my toe into AP. My interest was piqued while on holiday in Cornwall a few weeks back. I took some very basic (and out of focus!) shots of the Milkyway, and was impressed with what detail a single 30 sec exposure teased out. Now, general wisdom states that to get into AP, one needs to start with a decent, solid mount such as the HEQ5. I’m not one to argue with wisdom, but I don’t have the funds for big mount right now, nor for any guiding stuff to make things easier, or even a dedicated astro-cam! So, I have decided to see what can be done on a real budget with the kit that I currently have. The only addition I intend to make is to add the Dual Enhanced motors to the mount. I'm getting these for my Birthday at the start of October! Over the coming months, this blog will highlight the ups and downs of my journey. The aim is to start simple, and work upwards as my skills and patience get better!! I have also discovered the 'Imaging with the EQ3 mount' thread here on SGL, so that will be a good guide as well. I intend to try widefield to start with – using my DSLR directly connected to the EQ mount. I also am going to attempt to use the webcam for Lunar and some Planetary photography. Moving on, I may even try some AP with the Canon attached to the 150PL – but lets walk first eh?! I am also planning some DIY on the scope and mount, and will do my best to document this as well. First job is some ring rotator’s, and that will be in the next post! I hope you drop in and see how I am getting on!
  9. 2 points
    The spider hub came together tonight- bit of a mare as it’s glued together with high strength retaining compound which gave me about a minute to assemble everything and try to align all the screw holes - needless to say it was a right panic not helped by a friend deciding to strike up conversation at the critical moment. Wish I hadn’t rushed it as it’s not perfectly aligned and not much I can do about it now but it’ll do I think. It’s getting a bit hefty though which is a worry- 200g already but that’s all the chunky bits bar the mirror itself. A lot of that is the central 10mm stainless shaft- might think about replacing that with aluminium or at least drilling a bore all the way through. the adjuster screws need to be shortened a bit too
  10. 2 points
    Been working on the handset today and I think I'm almost ready to get the parts printed- exciting!
  11. 2 points
    Working on the motor mount this evening- needs a bit more work but the general idea's there. I'm going to use a magnetic coupling and am thinking to make it quick release so I can take it off if I don't want to use it.
  12. 2 points
    After tinkering with the smaller K40 we decided it wasn't quite up to our needs and decided a small upgrade would be more beneficial in the long run. A 12 hour drive and overnight stay in the Lake District later and we arrived back home with a larger 50W machine, a second hand 80W CO2 tube and upgraded power supply. The 80w upgrade will have to wait as we want this machine cutting asap. It's all set up and running now, but waiting on some extras to make the process a little healthier and cleaner. New extraction system (a bouncy castle blower), a water chiller, new focus lens, and a load of stock is due to arrive (3mm plywood, mdf and slate coasters) Took a while to get aligned, but is cutting 4mm MDF in one pass now so happy with that. Once this is up and running fully I can concentrate my efforts on finishing up the CNC build.
  13. 2 points
    Hi everyone, Note - entry written Thurs 17th Jan Well, its getting busy at work, and at home now. Coupled with work, my daughter is approaching the end of her A-Levels so she is massively stressed out with both her course work, and her uni applications. I can’t quite believe that my little girl is going to be leaving home in September. Only seems like yesterday that she was getting ready for her first day at school . . . . I am going to find that day very hard I think. We spend our lives looking after them, and raising them for this moment, but it doesn’t make it easier does it? Anyway- that day is nine months ahead of us, so I won’t dwell on it just yet!! Last night saw a decent break in the clouds. According to the forecast, a cold front had moved through and lo and behold the sky cleared mid to late afternoon, and the temp dropped noticeably. I took th tube out about 7:30pm, and left it a good hour to cool. Following my little process, I set the mount up inside, and then carried the whole thing outside. Mounted the tube, balanced it and I was ready. Again, I only carried out a rough polar alignment – looking through the centre of the mount I centred Polaris and I was ready to go. The evenings viewing was all about the Moon, so I had set up the scope in the garden, rather than round the back of the house. Yeah there was a lot of LP from the street light which I have dubbed Rigel, on account of its colour and brightness, but as I was just looking at the moon it wasn’t too bad. I started off at 48x with my 25mm and spent a good half an hour just taking in the view. The atmosphere seemed quite steady, and I took in the amazing detail along the terminator. About this time, my 11 year old lad came out with his coat and hat on! I moved the tube round for him, and he spent half an hour out with me which was lovely! He kept looking through the eyepiece, and then up at the moon, not quite believing the detail he could see! We upped the mag to 120x and while the image was a bit dimmer, the seeing was still very good and steady, and between us we looked at Sinus Iridium, Plato, Clavius, Tycho and Copernicus. He was a model student lol! Asking me loads of questions about what he was looking at. He only went in when he got too cold bless him!! So, another successful night with the 150PL. I have begun to tick off various items of the Lunar 100 list. I want to take my time with it, and not do it all really quickly. I also want to go back to various locations at different phases / illuminations, so as to pick out more detail in them. I have downloaded an Excel list of the features, and added a big map of the Moon showing their locations. I have also downloaded a really good Moon Atlas which is helping ID loads of smaller craters – the smallest I saw last night was about 10 miles across I think. Anyway – here’s hoping the skies keep clear for us all!! Cheers Nige
  14. 1 point
    Finally bit the bullet and knuckled down to wiring the handpiece- really made a rod for my own back though with the very tight space for the wires...it’s going to be really tricky getting the other half of the housing on there without squashing wires But it works-almost perfectly-almost that is except the pwm on the LED isn’t pwming I swapped from a nano to the new Arduino nano every and I’m guessing the code isn’t totally compatible... 0E01F364-3061-4211-904D-1334A76EFE8A.MOV
  15. 1 point
    Initially I planned to make the focus motor quick release and the magnetic coupling made some sense but I ended up going for a simple screw mounted motor so it makes less sense now But it’s done now and it works really well- better than I’d expected. It allows for lateral misalignment yet is a nice stiff rotational coupling for the sort of torque required to turn the moonlite knob. A ptfe pad keeps the magnets slightly separated so the two plates can move a little easier against each other. The black magnet holder on the focus knob is 3D printed and a press fit on the knob
  16. 1 point
    A new improved version of my "GinaRep Mini" 3D Printer. The first version used cord for the drives whereas this one will use the standard timing belt for X and Y and trapezoidal screw drive for Z. I also expect to use a stout wooden case of 18mm plywood like my Concorde printer, for maximum rigidity. This is to be a specially accurate 3D printer with option of nozzles as small as 0.2mm. Print bed will be 200mm x 200mm with around 200mm printing height. Essentially this is to be a reduced size, higher resolution, version of my Concorde printer.
  17. 1 point
    Disappointed with the function of the design yesterday due to friction issues I’ve modified it- it now has only one spring and 4 screws. The spring keeps the indexing screw in contact with the v-groove in the mirror cell top plate. Adjustment is achieved by slackening all the screws then adjusting the tilt to focuser angle with the indexing screw, and the focuser-axial rotation with the 2 side screws then all 4 can be nipped up to lock it which is better than just relying on the springs I think. The movement in the video is extreme but shows the arc of the movement around the ball joint and the function of the swash plate. In real life I’m not sure the small adjustments required justify the swash plate really but it at least stops the screws digging into the aluminium. It works C3A6ABFC-96A1-4C98-82CE-3CDB042F09E6.MOV
  18. 1 point
    24C2AE88-8FBD-47E7-BD34-716FB9018988.MOV Managed to square up the waveform for the step at the expense of halving it’s max frequency But I’ve changed the driver board for the version that actually has half step input so my new max speed is about 3sec/rev which looks ok I think. It’s slmost working how I want it but I need to figure out how to shape the response as it’s too long in the very slow movement then suddenly shoots off into high speed- not sure why as the step times should be linear from the pot Needs some thought Mark (Hopefully the video will load better this time with different codec)
  19. 1 point
    I've offered to give a talk with pictures to our local social group and thought a Blog on here would be a good place to prepare and assemble it. Also, I would welcome any comments and suggestions. I have a few ideas and will see how it progresses. I will probably take me several days to get my initial ideas sorted out.
  20. 1 point
    INTRODUCTION This is a tutorial explaining how to install an operating system and software into a micro SD card to use in a Raspberry Pi 3B+ for astro imaging and control of the relevant hardware. The software to capture images, control camera cooling and other things such as the mount etc. is called INDI and provides a set of drivers to control all the hardware. The Raspberry Pi will run in what is called "headless" mode - meaning that no human interfaces are directly connected to the RPi - instead the RPi is connected to the local area network (LAN) using either Ethernet (preferred for speed and reliability) or WiFi. Everything is then controlled from indoors on a computer also connected to the LAN. This computer is called a "client" and the Raspberry Pi a "server". This tutorial will detail all the steps involved in installing the operating system and software - there are rather a lot of them, hence the need for a tutorial but there is a script that is downloaded that does all the difficult stuff. I believe that anyone with some knowledge of computers should be capable of following these steps and setting up a working Linux based astro imaging system. The Raspberry Pi can be put on the pier (or tripod) or even directly on the telescope mounting and would replace a laptop for instance, reducing the use of long cables etc. The operating system used is Ubuntu Mate and involves using a monitor, keyboard and mouse (or trackball) in order to set up the operating system and enable remote control before the RPi can be used headless in the observatory or on a tripod. The Raspberry Pi is a "proper" computer though a bit slower and with less storage space that a desktop or laptop. When powered up the operating system goes into a setup routine and you just have to answer the questions, same as when setting up any computer. Near the beginning there's an opportunity to set up WiFi so you'll need your WiFi password.
  21. 1 point
    Hi all, As you may have read in one of my previous posts, my job with Greene King sees me coordinating till and IT installations during pub refurbs. Well, these last four weeks have been solid. We are trying to get as many pub refurb projects completed before the end of this month. Doesn’t do to have pubs closed at the busiest time of year! However, things are beginning to slow down on that front – although the meetings for jobs starting in the New Year are already coming in! This, added the fairly rotten weather have meant I have not been out with my binoculars as much as I would have liked. I have managed a few short sessions outside though and have seen the following: Venus – I get up early during the week, and always poke my head outside to see what the weather is like! Saw Venus was up, and quickly popped on my slippers to take a look. It was bloomin cold!! The sky was just beginning to lighten, but the view was crisp and the planet showed a definite crescent phase! I was so pleased!! Mars – I can’t see a disc, but the orange hue shows up well. Must wait to get the 150PL for a proper look!! Moon – again, impressed with the views I had. Observed the moon over a number of different phases, from just past new, to nearly full. The detail I was able to pull out along the terminator was pleasing. I have downloaded a Moon atlas, and am challenging myself to learn as much as possible on the geography of the Moon. Once I get the 150PL I am going to try for the Lunar 100! Messiers – I have downloaded a Messier catalogue spreadsheet, so I can start ticking off the ones I have seen. Not really had a chance to look for some of the dimmer ones, but (obviously!!) I have ticked off M31, 42 and 45!! I think I caught M1, but not too sure at the moment. I was in my back garden, and the LP was quite bad. Other stuff – I have downloaded a Plane Radar ap for my phone. I keep an eye on it during the day, and if I see a large commercial jet heading over, I pop out to take a look. An A380 at 33,000 feet is quite a site through the bincoluars!! I could very clearly ready the ’Emirates’ logo in red and white under the wings. Thanks for reading! I will try and do another blog before Christmas, work and weather permitting! Cheers Nige
  22. 1 point
    Well, it appears to have been over three years since my last Blog entry . . . . . so what's been happening? Well, shortly after I my last entry, I was made redundant from my job as a Projects Coordinator. When I say 'Redundant', I was contracting, and the work dried up which was pretty crap. However, I wasn't out of work for long - got some more contracting work, and then just over a year ago I got a perm job with Greene King Pub Co. as a Regional Systems Manager - basically, I look after about 500 pubs IT equipment. My region is East and West Midlands, and the North East of England - so anywhere from Kidderminster in the South, to York and Scarborough in the North. It's a lot of driving (about 35,000 miles per year), but I love it! I get to see loads of the country, and always manager to catch Pop Master on Radio 2 now!! So, back to it - last time I blogged I was after a new scope. Well, I still am!! I have got myself a pair of Celestron Skymaster 20x80 bins as a stop gap, and have managed a couple of evenings out with them since I got them on my Birthday a few weeks ago! I still have the EQ3-2, and have now decided to get myself a Skywatcher 150PL OTA. I have been doing lots of research, and I think it is a good compromise between aperture and focal length. My 10 year old son is now getting interested in space and astronomy and to be able to see the planets is especially important!! Looks like I will have to wait from Crimbo for the scope - I have sent my letter to Santa already, and I am pretty sure I have been a good boy this year!! So, I hope to start Blogging weekly again now, to start with, with observations with my new bin's, and the in the new year, with my shiny new scope! Thanks for reading! Nige
  23. 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
  24. 1 point
    Measurement of Doubles and a Jovian Moon - Baader Micro Guide Introduction The reason for this rather long blog entry is to highlight what has been possible using simple and relatively inexpensive gear to measure the separation and position angle of a number of double stars and the sizes and distances of various objects within the Solar System. The preliminary goal was fivefold: to further skills in star-hopping and to gain a deeper understanding and appreciation of star magnitude. to garner some experience in measuring double stars as accurately as possible. to work out the sizes and distances of a number of night sky objects. to evaluate the capabilities of the 4” refractor. to pass on information that may be of interest or use to others. The Gear Mounted on an equatorial CG-5, I used a four-inch Tal 100rs f/10, a Celestron x2 Barlow and a Baader Micro Guide. This particular eyepiece is an Orthoscopic Abbe with a focal length of 12.5mm and equipped with a laser-etched reticle and screw on red-light variable illumination system. The multi-function astro-metric eyepiece provides sharp images across the field of view and has a twist up and down focuser which is not for eye-relief but to sharpen the finely etched designs for the observer. When focused at the centre, the edges of the scale do not blur and are crisp throughout but might be difficult to read on occasions due to the illumination system sometimes being uneven. There is no glare, stray light or internal reflection from the illuminator but on tighter doubles with a dimmer secondary component or on faint DSOs, for example, one finds they fade between subtle differences in reticle brightness. Lessening this brightness to capture the dimmer object sometimes makes it complicated to read the 360º protractor scale and I have found that the best remedy on such occasions is to dim in and out and use the eye’s memory to capture the reading. The sharply etched reticle scales include a 360° protractor at the edge of the field of view (4), a number of concentric guiding circles (3), a semicircle (2) and a linear scale across the centre (1). For general beginner’s use, the Micro Guide will be very useful to those who wish to work out seperations and angular distances of binary stars and sizes and distences of Solar phenomena, Lunar features, and other objects found within the Solar System and beyond. Focal Length In measuring a binary star’s separation in something as small as arcseconds, it is important to maximise that separation by using as much of the linear scale as possible. By using a barlow, one effectively increases the telescope’s focal length which in turn ensures not only a greater magnification but also a more accurate measurement along the 60 divisions etched onto the Micro Guide’s 6mm linear scale. This means that if separations or sizes are to be measured evermore accurately with only this eyepiece, different and greater focal lengths will eventually be required. Calibration Before being able to use the Micro Guide it is necessary to calibrate its linear scale, that is, to estimate the number of arcseconds in each division in accordance with the given telescope and if used, the given barlow. If ever the barlow or telescope is changed for another or not used, one must repeat calibration with the new set up. There are a number of ways of going about this and I include two methods, ignoring those given by the instruction manuel. The Split Method Find a known double star and note the number of divisions on the linear scale separating the primary from the secondary. If, for example, Albireo has a separation of 34.7” arcseconds and I see that this separation spans 4.6 divisions on the reticle’s scale, then I conclude that each division is 7.54” arcseconds in length. It is a good idea to measure the chosen double star 30º above the horizon to avoid overt atmospheric disturbance or refraction and to take a good number of measurements of that given star to find the mean average. For this method I chose similar partners in beauty but of various separations none of which were so tight that measurements would be rendered near guesses. StarRho ( ρ)Counted DivisionsScale ConstantAlbireo34.7"4.87.23"Almach9.7"1.37.46"η Cas12"1.77.06"ζ Lyrae43.7"5.97.8"Summing and finding the average I now had a workable scale constant of 7.38" which would remain valid so long as I used the same gear. The Drift Method Again, the drift method is to determine the scale constant – the number of arcseconds per division - but I feel gives a more detailed approach and one less reliant of guessing. However, with that said the final scale constant was very similar to the Split method. Turn off any mount drives and time the passage a given star makes along the length of the linear scale from zero to sixty. The star doesn not have to be a double but will need a stopwatch counting to the 100th of a second. It's a good idea to find a star above 30º declination and not too near the Cestial Pole. You turn the eyepiece until the star drifts exactly along or parallel to the linear scale and as it crosses the zero line start timing until it crosses the sixtieth division. You repeat this process about 20 to 30 times in total over a number of days. To ensure as much accuracy as possible try to measure three different stars over a week and with the various timings for each star, calculate their mean average. The Drift’s Scale Constant You’ll then need to convert these particular results into arcseconds with the following formula: S.C. = 15.0411 (T.avg) cos (dec) / D S.C. – Scale Constant. 15.0411 – Earth’s rotation rate per hour in degrees. T.avg – The given star’s mean average drift time. Cos (dec) – The cosine of the star’s declination / - Divided by D – The number of division on the linear scale And that’s it. The resulting figure will be your scale constant and will remain valid so long as the optical gear you use remains the same. In my own case, I found that the average scale constant was again around 7.5” arcseconds per division. Putting Numbers into Practice Over the following days, I tried to measure a number of double stars in the constellation of Perseus. In particular, doubles that I had never worked with. I chose Eta Persei, Struve 331 and Epsilon Persei as guinea pigs for the experiment. I took a number of measurements for each star and again estimated their average separation. The following highlights the concluding results where Est Rho is my estimation and Rho is the official separation. StarEst Rho ( ρ)Rho ( ρ)Errorη Per28.5"28.3"0.7%Σ 33112.9"12.3"4.8%ε Per8.1"8.7"7.4%As can be seen the margin of percentage error is significant and there is room for improvement. Nevertheless, the results were all within 1” arcsecond of error which accords with the kind of results expected from the Micro Guide. Baader informs the reader that “...such measurements can be estimated to an accuracy of about...2” for a focal length of 2000mm.” Working Out Position Angle I found that working out how to take a binary’s position angle quite complicated but eventually the following procedure was taken. The binary is centred in the eyepiece and aligned in such a manner that both components drift through the bisected middle linear division marked 30 on the Micro Guide. The two stars are allowed to drift toward the etched 180º semi-circle and as the primary crosses the inner 360º protractor scale one reads the given angle. It’s a good idea to take a number of measurements, but better still, place those stars dead centre for a general reading error of about 1º to 2º degrees. Measuring Sizes and Distances To measure size (S), count the number of divisions the given object takes up on the linear scale (sc). Divide this number by your set up’s focal length (fl) which will give you a general image-size (i). Multiply this with the known distance to that object (d). S = d (sc / fl) For example, to work out an estimate of the size of Ganymede, I found that it measured no more than about 0.01mm or 0.02mm on the linear scale: a mere dot on the etched reticle. The mean average of this number was divided by my set up’s focal length, giving me the estimated image-size. Noting that Jupiter was about 4.8 AU from Earth (718,069,776km) and that Ganymede has a average distance of about 1,605,000km from Jupiter, I calculated that Ganymede was around 716,464,776km from Earth. This number was multiplied by the image-size giving me a rough size of Ganymede at around 5,373km in diameter. An error of about 2% or around a 100km out. To calculate distance (d), you divide your focal length (fl) by the image-size (i) and multiply this by the known size (s) of the object. d = s (fl / i) Ganymede’s distance from Earth, I knew its size was about 5,373km (really its 5,268km) and was measured on the scale at about 0.015mm. You then divide the focal length by that image-size and multiply by the size of the object. In my case, I found Ganymede’s distance from Earth was about 716,400,000km. Again, an error margin of around 2%. Conclusion The Baader Micro Guide does not come cheap. In Europe it sells for around €165. In the boxed package you receive instructions (often vague), a decent 12.5mm Abbe Orthoscopic eyepiece with the built in finely etched reticle and a battery operated screw-on illuminator. Most will probably think that such an item is an unnecessary expense to include in their eyepiece collection but to counter this argument there is something rewarding in the challenge of meticuously recording and calculating distances and angles and sizes and separations – even if the experience can sometimes be frustrating and that these numbers have already be worked out for you. I have found the Micro Guide to be a useful resource for not only testing patience and recording skills, or the acuity of vision but also an aid in astronomical study. Like sketching or logging, the astro-metric eyepiece helps increase observing skills for it forces you to take note rather than just casually glancing. Indirectly, it helps increase knowledge about the objects you are looking at, for it is necessary to research such variables as size, distance, separations and position angles and by researching these variables and actively working with them, overtime you are gradually able to estimate such things in the field. Finally, it also acts as an impetus to structure a part of your observing session. After a good month with the eyepiece, working with the Sun and objects of the Solar System, I also feel I have come to appreciate a lot more such diverse factors as the quality of my optics and observing site, the effects of atmospheric seeing, sky glow, astronomical and mathematical data, patience, fatigue, mental disposition, and so on. Such insights will not only deepen your understanding of stargazing but also in coming to understand a little more about yourself – which afterall, must be one of the most important goals set out for us.
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