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About focaldepth

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    Cleveland (UK)
  1. Depend on the USB speed, my ZWO is USB3.0. Linux usually runs on quite modest hardware but can't perform miracles. To give it a go, download the UBUNTU usb image, use RUFUS (under windows) or DD(under linux) to copy it to a USB. boot from the USB and try it in live mode.. If that work re-boot and install, most of the install questions are easy to answer.
  2. Hi Paul, I have just replied to an old PM you sent, and saw this. The SW Skymax 150 is not a standard SCT thread. I had an adaptor made to go from the 150 to a borg focuser, I could dig out the details, from somewhere, I think it was an m69 thread.
  3. Thanks for suggestions. I should not speak too soon. (Lucky I am not superstitious(cross my fingers)). BUT.... I ordered an HP laptop from Ebuyer without Windows(£180), yesterday evening, arrived this morning. Installed Ubuntu, kstars, indi, stellarium, and a bunch of other stuf. Plugged in, HEQ5, SXH18, SX Filter wheel, Polemaster, SX Costar, game controller, ASI 174. Guess what, they ALL worked first time. Linux just isn't fun any more, no more rebuild kernel down load source, fix deliberate mistakes..make files....Too easy. Just a few things I am stuck on, I suppose I should read a manual or something: Joystick slew rate. Filter colour names. Scripting. 12V charger for this laptop. We're off to Dalby on Thursday, I wonder if I will have it all set up and working. Oh and my Windows 10 laptop has finished another update, and it works as well. I will have to reload the astronomy serial port drivers but that is expected.
  4. Great, you have convinced me, I am moving. Tonight I have hit the Nth Windows 10 screw up, tonight the windows button has stopped working. There must have been 12 times so far when I have a clear sky, power up one of a few laptops I use for astronomy, and " Windows is about to enhance your life experience, please wait a few minutes"..... " now rebooting", !windows is installing your updates"......great finished 4 hours later. Now all the camera and ascom drivers have been replaced with "improved", non-working Microsoft one's, again. Oh look. the sun is rising. I came on here tonight to check on the Linux status and found this. Being a Debian hardcore Linux user, I'll give it a go. I will probably still process the data in Windoze, as a lot of software I use is Windoze only. A Question though, are there reliable and usable packages for capture from SX, ZWO and Celestron cameras and filter wheels and SW mounts for DSO and Planetary, with scripting and guiding? John.
  5. Thanks again Olly, I'll be sat waiting this afternoon while my wife is at a machine knitters meeting, so I'll be drawing triangles, circles and squares and thinking photons. So the Quattro it is. John.
  6. Thanks for the suggestions. DaveS, my portable mount is an HEQ5(belt drive) and yes I can not guarantee 0.6" guiding. Good thought, I had not considered the mount. Hmm. Ollypenrice, wise words, the old F ratio myth, I am going to have a long think about the maths of this photon counting. I will read your post seven more times before bed, and sleep on it. The Quattro is easier to set up and focus, and it stays focused forever once set. Some how I expected this answer so it looks like the Quattro it is. There are a few similar sized galaxies high up at the moment so I could try for one and include a few extra free galaxies in the frame as well. Probably M51. Or not. Thanks for the advice.
  7. Hi all, One simple question, Which of these 2 telescopes is better for imaging M51 sized objects? Skywatcher 200mm Quattro Skywatcker Skymax 150p My head is exploding trying to tackle this logically. It is basically resolution vs exposure time. I do have other equipment but let's keep it simple. Here are all the numbers: (based on Starlightxpress H18 camera and target M51) (numbers rounded for ease) SW 200 Quattro SW Skymax 150p Focal Length 800mm 1800mm F Ratio F4 F12 Object size 11' x 7' 11' x 7' Field of view 1.3 x 1.0 deg 0.6 x 0.4 deg Dawes Limit 0.57” 0.77” Pixel scale 1.4” 0.6” Sky Resolution 2” (???) 2” (???) So the: Quattro has better optical resolution, Skymax has better pixel resolution, The Quattro can collect more photons and/or shorter exposures. (eight times more) Skymax has a better framed image size. So which telescope would you choose for producing the “best” image? I could try them both and see but unfortunately I don't get that many clear nights when I am free to do imaging. We are off to Kielder soon and I want to make the most of any clear skys that may occur. Other suggestions are welcome as well. (There was a man wandering lost in the woods when he met another traveller and he asked for directions. The reply was, well, I wouldn't start from here)
  8. For future reference here is the solution I found to my problem. Thanks for the above suggestions. Problem: SW ST80 with TS Crayford, 1.25 diagonal, Quark Chromosphere, SW plossl eyepiece could not achieve focus. Solution: 1) Replace 2" to 1.25" adaptor with Starlite low profile one (zero length) 2) Replace diagonal with Baader T2 diagonal, plus Baader low profile eyepiece holder. 3) Swap the very long Quark 1.25" nose piece with one from a plossl eyepiece. So we now have 12mm spare back focus. (the focuser tube is out by 12mm at focus)
  9. Thanks all, I bought a Baader T2 with adjustable holder kit. I can now focus the Quark but with only 1-2mm focuser travel left. I have also ordered a low profile holder. So Averil and I have now had first light through a thin veil of cloud. Looks promising, can't wait for some clear views.
  10. Stu, thanks, I already had some of that data but found some new data for me to consider. It is great to have some real numbers ronin, Another data point, thanks. Alien, DREMEL! Sould be accurate enough to keep the rays in sync to 1/12 lamba. I'd thought about a lathe but my one is too small to even think about it. I wonder how other people do it. I have a feeling that this diagonal will cost a little more that my lovely lady had budgeted for.
  11. I actually posted a complete description but it was so long that I got no replies, so I wrote this short version it. Summary SW ST80 + TS crayford, zero length 2-> 1.25 adaptor + Quark, SW Plossl + extension focuses great. TS Crayford is same length as original focuser. ST80 + any diagonal + quark + plossl can't focus. I have measured and calculated that less than 70mm length diagonal is required. The consensus on the web seams to be that prisms use less back focus than mirror diagonals. I don't have any 1.25" mirror diagonals, only 2" which are way too big. I will try and borrow one though. I wanted to know that a particular diagonal was correct before buying one. I have identified Vixen Prism, Celestron Prism and Baader T2 Prism as possible but want to know the light path length including the eye piece holder. first. For full story see
  12. Suggestions for a short light path diagonal. Hi all, does anyone have any suggestions for a 1.25” 90 degree star diagonal or prism with a short optical light path? I have calculated that I need less than 70mm (including eye piece holder) but the shorter the better, to give some focus head room. All my current diagonals, including WO and SW 45 degree prisms are far too long. I am already using a zero length 1.25” adapter in the draw tube. Google is not finding the information I need. Thanks in advance.
  13. OOps sorry, i Have just posted a question on Solar Imaging. It should be in Solar Visual.

    Questions about our new Quark setup, diagonals and suggestions.

  14. Questions about our new Quark setup, diagonals and suggestions. Hi All, I've not been on here for a while and have hardly had a chance to the see the light of night this year. Quick history. My wife, Averil(Yarn) decided she wanted to buy a solar scope set up. It had to be simple(ish) to use and without polar alignment hasels. We weighed up Lunt and Quark etc. and with a modest budget, finaly settled on and bought the following: Quark Chromosphere. SW Discovery Alt/AZ mount. A handfull of SW plossls. A few other bits to glue it all together. The plan was to use my old ST80 (ex guide scope) So we got a TS Crayford focuser as well. Now then, same old story, lack of back focus with the planned setup (or some would say front focus, depending in the minus sign). Some measurements at infinity focus: All with SW ST 80 + TS focuser + low profile (zero length) 2 inch to 1.25 inch adaptor 10mm Plossl + ST80 + SW cheap 45deg 1.25 prism = 41mm Draw tube 10mm Plossl + ST80 + WO 45deg 1.25 prism = 33mm Draw tube 10mm Plossl not possible with draw tube. 10mm Plossl +61mm extender (improvised) 73mm Draw tube = 134mm Quark + 25mm Plossl = 69mm Draw Tube Quark + 10mm Plossl = 72.5mm Draw Tube Some Calculations: SW cheap 45deg 1.25 prism = 134-41mm = 93mm optical length WO 45deg 1.25 prism = 134-33mm = 101mm optical length Quark = 134-72.5mm = 61.5mm optical length Hence: Quark + Diagonal < 134mm Required Diagonal < 134 - 61.5 = 72.5 Finally my questions: Do my calulations make sense? Does any one know of a 1.25inch (or even a 2inch) 90deg diagonal with a total optical length of <70mm? Any suggestions to convert this into a decent solar setup without breaking the bank? Thanks in advance. John (and Averil)
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