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    Investigate911
    Latest Entry

    Hello, I am relativley new to astrophotography , and I have a question. I'm using a n 8 inch Shmidt Cassegrain Celestron Telescope, with a 2x Barlow and a webcam. I tried removing the lens from the webcam exposing the chip, however it completly ruined the image, I would just get a big blur of light and shadow, so I put the lens back into the webcam, and butt the camrea up to the eyepiece with a special jig. I am using a Logitech C920 webcam. I notice people with webcams getting these pics of Jupiter and they are large images of jupiter , everytime I shoot video of jupiter to use with Registax , my image is so tiny ! I Was wondering if there is anything I can do to enlarge the image without distorting it to much . Thank yall

  1. 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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    I would propose the material currently missing from our universe was all there at the Big Bang moment but over the billions of years much has radiated off into the void. Every star,pulsar,quasar and black hole radiate out, from birth, their contents over time. Some of the material would be retained but much would be lost especially at the outer fringe of the universe where there is nothing to stop it from leaving the universe entirely.

    As an additional thought, is it possible that the expansion of the universe is caused by the pressure of all the radiation flowing out from every body onto every other body. I remember the ECHO satellite being pushed out of its orbit by sunlight.

    Any reader will soon determine that I am a rank amateur despite my 77 years.

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    IenAABQDVmk32Xq
    Latest Entry

    Hi. I have a Star-watcher 200P scope on a EQ5 Mount. Is it easy to upgrade it using a SynScan Go-To Upgrade kit for standard EQ5? If so please could you give me some tips to help?

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    AaronLPK
    Latest Entry

    Hi, i just bought a skywatcher explorer 200p and yesterday when i went out side to have a look, i would look through and see a bright circle with the front spikes in.

    what do i do to fix this???

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  2. It's been quite a few months now since I've been out for any serious sessions with the Telescope. However the bad habit of smoking does get me outside on a regular basis where naked eye observing was regularly taking place during those months.

    My latest purchase is a GoPro Hero 4 Silver. Working in IT and having a love of gadgets the camera has opened up a lot of opportunities which also include using it for a bit of Astro Photography.

    I only purchased the camera a few days ago and the forecast was goof for some clear skies during the evening. Leaving the GoPro in its waterproof housing the camera was mounted onto a Gorillapod and just sat on the decking outside my back door. The light in my back garden was very poor in not being able to see very much of what was around on the floor. I set the camera to take 30 second exposures constantly where over the 2 hours it recorded 240 images.

    When I started viewing the images I was absolutely amazed as to how much detail it had picked up in my garden as well as picking up the movement of the sky. The amount of stars captured was also quite a surprise.

    A well worth purchase where I hope to produce a lot more images similar to these but in some better locations.

    http://youtu.be/19RiC0DMoX4

  3. blogentry-38966-0-35827800-1423083299_th

    Ok, so the photo isn't a classic but to me it's a masterpiece :-) ...the first time I have ever seen Jupiter through a telescope let alone been able to photograph it. Pretty awesome to be honest considering I've managed to take a photo of a planet over 550million km away and whilst I don't think it'll win any prizes it has made me a happy man!

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    29/01/2015 - 30/01/2015 New toy day - laser alignment tool. I thought the 130SLT was working pretty well until I checked the collimation: way out. There should be a warning that your new scope will be off focus until a laser alignment tool is used and the collimation corrected. So that done I got the scope outside only to have the batteries die. Then I found that my 12V PSU is the wrong polarity. So I got the NiMH fast-charged, and of course the skies clouded over 8/8 with some heavy stuff from the west for the rest of the foreseeable.

  4. So the much belated start to 2015, while the real year started 17 days ago but, with the weather in Edinburgh having been on the terrible side of atrocious, the star gazing year only got going last night. For the first night of the year i thought i would do something a little different and i had my first night out at Harperrig Reservoir (Edinburgh). What a place it is; you get a slight red glow to the NW from Edinburgh/Edinburgh Airport and the lights of one house but, for the darker sites that I've been too and to be fair it's not many, it's the best.

    Normally I'm a city centre amateur astronomer; sometimes when i get out to a darker site my mind does get a little blown away. I'm used to Orion slowly rising over the houses to my left not being sat there fully out in all its glory. I'm used to star hopping with a limited number of visible stars and using "Turn Left at Orion", so when i can see so much i often forget what to look for and just end up gawping up at the night sky and not using the scope. I suppose my normal plan is to just look out of the window and if its not cloudy get the scope out, not very scientific but it can be fun. Last night i went out with a plan, Comet Lovejoy was the prime target, Jupiter and then as many Messier/NGC items i could throw in and this was the haul;

    Comet Lovejoy (It was like a star with a fuzzy nebula around it, but don't worry others confirmed that it was the comet)

    Jupiter (all four moons and some great detail and colour on the planet itself)

    NGC1981

    M42(M43)

    NGC1662

    Pleiades

    NGC2169 (The 37 Cluster)

    NGC2175

    NGC2129

    M35

    M36

    M37

    M38 (Starfish)

    M1

    M31 (Andromeda)

    M33

    NGC752-C28

    NGc2244-C50

    NGC2264 (Cone Nebula)

    It was getting cold, -4 when i got in the car and i'd forgotten my flask of tea so enough was enough and my first night of 2015 was over.

  5. Happy days V0.11 is finally available - see post http://stargazerslounge.com/topic/234260-lodestar-live-v011-beta/

    Looking forward to seeing how people get on with the new display processing controls!

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    dwaynerefford
    Latest Entry

    I brought my son a 127 SLT Telescope for Christmas this year after seeing a few videos online.. I was taken back on what you can see with the scope and that is why I purchase one. After getting the 127 SLT setup I pointed the scope to the full moon and here I get a bright light. I tried focusing in the telescope focuser knob but still the moon shows up as a bright light.. I then point the telescope to a building about 100 to 200 feet anyway and I was able to focus in on one brick with no problems.. I'm using the 20mm eyepiece and I'm unsure what I doing wrong.. I email Celestron tech support a few days ago and have not heard back.. any advise you can give me would be appreciated..

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    Bright and misty tonight.

    Having a go at the M38 area.

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    So I have had my scope for a month now and have had only about 2 hours with it in the dark pointing upward.

    And again this evening another damp rotten evening, so it looks like it's back to the books for another read on Astronomy for the newbie, me, I have purchased 6 in last 4 weeks and have read about 3, so still a few more pages to plough through, it would seem that clear skies are a rareity in my part of the woods, damn this weather, however it has given me time to think about how I can disable the really bright street light at the bottom of my garden, one of 4 within 50 yards of each other, they like their lights around here.

    Which had me thinking, is there a website that has viewing sites around the country where I can go set up my scope without street lights everywhere? are there any other astronomers in my area that know of such sites? Should I create a website just for the purpose of passing on this information? Or am I just bored looking out of of a rain splattered window hoping for the rain and clouds to go?

    I will now go and watch my recordings of the Prof Brian Cox expaining about the Sun, Earth and all the other interesting things in The Wonders of the Solar System and Wonders of the Universe, who knows I amy actually remember something he says this time.

  6. toftm

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    Home from a great holiday in the USA, finally got to tick Kennedy off my list!

    Here's a little video :-)

    http://youtu.be/hzkS6aD01RQ

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    Here is a list of a few thing i saw on the night/morning of October 21/22

    M1 The Crab Nebula in the Constellation of Taurus

    M45 also in the Constellation of Taurus

    M36-37-38 in the Constellation of Auriga

    M42 In the Constellation of Orion

    And about 15 Orionids in a short period of time before the clouds rolled over and put an early end to my obseving for the night

    mick murphy

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  7. So it's happened!

    I've got a scope.

    My initial intentions of getting a small refractor were well and truly side-swiped by RobH on here doing me a corking deal on his ST120.

    Having thrown in some extras including the dovetail and scope rings, a basic electronic focuser, an old EQ3 mount and a couple of eye pieces within the price I came away a very happy bunny.

    Obviously the ST120 is is a BIT bigger than the ST80 size I was intending and certainly not what I consider suitable to go in hand luggage but it was too good a deal to pass up and gets me started.

    So I put the scope on my new EQ3 mount and was ready to rock.

    Obviously as a result it was cloudy that night. :rolleyes:

    There was no chance to try proper polar alignment as there were almost no stars visible due to the cloud.

    I pointed the tripod leg North as indicated and pretty much winged it.

    I christened the loss of my telescope 'virginity' with a quick look see at the moon.

    It's bright isn't it!

    Someone has obviously turbo charged it in the past as it fairly rocked out of view in my eye-piece.

    Between the cloud banks I was kept happily entertained for about an hour.

    The need to get up stupid early for work on Saturday morning closed play early but the latest obsession begins.

    Bamus on here has just accepted some beer tokens for a 2" T-adaptor.

    I just need a DSLR and camera ring now and I can confuse myself even more.

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    andyin2014
    Latest Entry

    I will be traveling by car and want to transport my telescope. I have a refractor and I understand this type is the safest to transport, any advice?

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    Jobie
    Latest Entry

    The sky is clear tonight, looking with the naked eye I caught sight of a star and there were other twinkling stars round it and also a line, having looked on the sky at night website I realised that it might be Urser majors galaxy. Has anybody else seen this?

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    American flyer
    Latest Entry

    Hi All

    I bought a Nexstar6 se as I have always fancied looking at the planets and stars anyway I am all set up but it's been quite cloudy.

    I have tried to focus on other things buildings etc but nothing comes into focus I know there is quite a bit turning the knob but nothing seems to happen.

    When I turn the knob is the inner mirror supposed to move because this doesn't seem to move at all , even when going from one extreme of focusig the the other.

    Can anyone advise is it me ? oris the scope faulty.?

    Best wishes

    The flyer

  8. Here is a picture of Ganymede seen through a 10" scope (NOTE THE PICTURE IS NOT MINE).

    So here is some evidence that It might be possible...

    I hope I really will see detail on Ganymede and the other moons.

    Alas Jupiter is not in the sky so i will have to wait :)

    blogentry-38322-0-92308100-1410535431_th

  9. Finally began to see something after some helpful advice from a couple of forum members. My error was not setting the white levels etc in relation to the histogram. It's all new to me - except in terms of ordinary photography, so I was in the dark - literally. I now have 'live' images which are essential for alignment and focussing. Conditions were not good, however, with an almost full moon, thin cloud and lots of dew. So I packed in knowing that I was at least on the right road and looking forward to next time.

  10. After a disappointing holiday in Devon from a clear skies point of view (great time otherwise), I returned to Essex last night to be greeted by a few stars in the sky. The view in Devon was North facing, different from my south facing garden, so I took my Dob out the front with its security lights and road junction and went hunting for the objects I had lined up for my holiday. This was to be a Cassiopeia night.

    Iota Cas. Found this after a bit of a struggle to even see the fainter end of the W! Once found however, this turned out to be a great test of my eyepiece set. Firstly, all 3 were just visible in the TV Radian 10mm. I tried a 2.25 barlow, but as usual, I struggle with barlows, maybe as I have a single speed focuser, maybe just because I struggle. I also compared the view to the Skywatcher 10mm that came with the scope and happily found the view not as crisp as well as narrower and darker, although still splittable. The barlow was pretty much unusable in this eyepiece.

    The Baader Zoom was tried, as I have not had a huge amount of joy with this EP in this scope. This was a happier experiment. The zoom is very useful at finding and then splitting and the 8mm full power (which is actually my highest power at the moment) also made the 3 way split quite easily. The barlow again was a bit of a blurry mess. I need to get some proper high power eyepieces it seems as the barlow approach simply is not working for me. Radian 10mm for the rest of the night.

    Another thing I noticed is that I am having balance difficulties with the Dob and think I need some counterweight to help prevent the forward tipping and the extreme tension required to prevent slipping.

    Next up was Struve 163 (can you tell where this list comes from!). I had already seen the triangle in my hunt for Iota Cas, so this one was pretty easy. What great colours! The C star was far enough away that it didn't even seem like part of the group. This is a mag 10.7 star, so nice to see how I can push the 10''.

    Eta Cas was a nice sight and quite easy to find and it was good to gauge how 13 arc seconds looks like in a 10mm EP. However, I could not find the next one, Burnham 1. Even with a clear guide, I just couldn't make it out and will leave to a night when I have more power and possibly darker skies.

    Struve 3053 needed a couple of restarts back to the starting star to get, doing the run from Gamma to Kappa and beyond. What a nice reward though. A littler Albireo, with a lovely and crisp orange and blue combination. From the spacing earlier, this looked a little larger than Eta Cas, and so it proves as this is a 15 arc sec difference, so getting a feel for this. To bring me back to earth, Sigma Cas completely eluded me after, and as the clouds started to roll in, I used my MaxVision 28mm to get a feel for stepping with this low power EP and judging distances between the main Cassiopeia stars (2.5 EP width for the Alpha->Gamma step by the way!).

    All in all, a very enjoyable hour or so and great to get some time and experience at the eypiece. I used a chair this time rather than a kneeling mat, and preferred it I think, although doing finder work with a straight through is a neck-cricker...

    Source: Cassiopeia Double night

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    blog-0098533001409423176.jpgThe story doesn't really start here, but I expect this is gong to be a common theme. It's cloudy.

    It's cloudy because today I decided to get rid of the red dot finder that came with my baby telescope. It's cloudy because I stuck my Telrad finder on in its place, spent a good 15 minutes making sure it was calibrated properly, and spent a further 20 minutes fashioning a homebodged dew shield for it out of a sheet of plastic.

    The Clear Outside forecast had been promising no cloud from 9pm and a six hour window, but by the time I had finished my Blue Peter job on the dew shield, this had slipped back to 11. Then midnight. The window had shrunk to two hours, and the dew risk from green to red. In the end the colours were changing so quickly I had a flashback to my first school disco...

    I managed to get out on Thursday night for my first proper sky hunting session, but dew managed to draw that to a close before I was ready for it to end. Newtonians don't need dew shields, said every source of information I could find but there was enough dew on the primary mirror to go swimming in. So I've fashioned a dew shield for the scope as well, out of an old camping roll mat. I was so ready for that six hour window...

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