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Posts posted by Daz69

  1. I made a start on my new dob base build this afternoon. I have a stock of 3/4" birch ply which are large off-cuts from previous projects which will look good when sanded and stained. I used the dob mount build guide from the Sky at Night magazine designed by Steppenwolf. However I'm not too sure that the sides are high enough even though I followed the Excel auto config figures that came up for my my OTA dimensions. I don't know if anyone else has this Excel program provided with the magazine feature who would be kind enough to double check for me?  

    I'm having a round base board rather than a square one, and the reason being is that I will mark the 360 azimuth degrees in this, and will have an illuminated pointer attached onto the base box. 

    So far, I have made the round base board and sides of the base box by gluing and biscuit jointing several boards from the off-cuts., and these are in the clamps to cure overnight. I'm using solid single pieces for the base board and the box base, as well as the altitude wheels. I've also blown up one of my routers, not happy. Must've had too much dust inside, but I'll strip it down and check it on another day. Luckily I've got 4 others as well as the one in my router table, so I reckon I'll get to finish this before they all give up :D 

    Rummaging through my odds and ends box, I found 3 brand new adjustable cabinet feet from when I put some units in the utility room, so that's a few bob saved. 

    Tomorrow's jobs: Route the alt wheels. Cut the box base board. Size up the front and side boards on the table saw for final dimensions, and once done, drill and screw these together in order to place on the box base. No glue at this stage. If I am happy with the side height (very much doubt it), disassemble and route out the alt wheel cups, route out the side openings and sand all faces, white spirit wipe all boards, glue and screw, base box made. If I'm not happy with the height, I will glue and biscuit another piece of ply perpendicular to the other boards as this will give extra strength, like a one ended wooden bread board. Finish will likely be stain and varnish IF they sand nicely. If they don't then I'll apply a pore filler, re-sand and paint. 

    I've not taken any photos so far as looking at photos of bits of wood isn't really interesting, but when It starts to come together I will get a few.

    I have also given some thought to making fine alt and az adjustment controls like fiestazetecmk2 has recently made. I have an alternator pulley from when I changed my old solid pulley to an over-running pulley on my car last year. I've also got some M10 threaded rod, will just need to get some other small bits, including a drive belt, however I do have a new one for my car hanging up, but will have to check for length. I'll make the hand wheels from wood (cheap skate!) and I have a good idea to help make them better to grip. However, these controls are not important at the minute, so they can wait.



    • Like 7
  2. Just now, tooth_dr said:

    Indeed that would be logical.  I'm pretty sure it runs off USB, so is there any benefit to using a power lead at the same time?  And I'm curious, what is the purpose of the powering it if it derives its power from the USB?



    Again, I would say that unless you use a shielded USB cable, the power lead inside the USB cable could (will?) cause interference with the images. It's not my field I'm afraid, but I do know that power cables do interfere with signal leads unless they are shielded. 

    • Like 1
  3. If you don't mind charging after each use, get a smaller one for ease of transport. I have a 110Ah for my caravan, and that is very heavy, certainly wouldn't want to lift that every time I used the scope. As I said to you before, I use a 9Ah but can join a second in parallel to give 18Ah. How much current does your equipment  draw? 

  4. 24 minutes ago, darren west said:

    I've seen cabled batteries but they req 240v 


    No they don't technically. They prefer, or advertise, that it'll need 240v to power a transformer to give around 8 volts to the dummy battery. If you use a "buck converter" (about £3 on ebay) and set the output to around 8v, you use 12v from your leisure battery to power the buck, and the output will be able to safely power the battery. I've just built a power distribution box with 2 of these bucks in them, where one will power my Canon. Check my post in DIY Astromomer forum. Here you go: 

    And this is how it all started:

    Hope this helps.


  5. Yes, that's right. However PC fans are brushless. It still won't cause any problems for the motor, except that the rotor just doesn't spin as quickly. PC fans will probably run even if your voltage input was as low as 3v, and will still work fine, just slower. A "PWM" is the flashier, more cleaner way of making something work slower/faster, cooler/hotter or dimmer/brighter by slowing down the DC ripple.

    I use a PC fan in a home made magnetic stirrer for making vape E-liquid at home, and that runs at 5.5v via an LM317T chip, a 1k ohm potentiometer and a 330 ohm resistor and various smoothing capacitors. If I used a 120 ohm resistor, I'd get around 11v. However because the mixing requires a long slow mix to start, if I had 11v running through, things would get hot and the carbon track potentiometer will eventually burn out. I could've used a PWM for this, but had the parts available to build my own. 

    • Like 1
  6. 16 minutes ago, abhoriel said:

    ............ assume you are adjusting the voltage rather than using a pulse-width modulation method.

    Not quite. You're slowing the voltage ripple so the motor spins slower. Pulse width is exactly that. The closer the pulses, the brighter, hotter, or quicker something happens. Turn the dial down to lessen the width and things get dimmer, warmer, and slower. 

    • Like 1
  7. 7 minutes ago, abhoriel said:

    Its really a balance between safety, allowing the device to be useful for larger straps and reliability. A fuse blowing in the middle of an imaging session might go unnoticed for some time. Where you draw this line is up to you.

    Absolutely. I started at 1amp as I'm more likely to use only 2 straps at once, one through each controller. If they blow then I'll go to 2amp. If I get to using both channels on each controller, then it may have to go up, but I don't see it getting to 5amp. I could be wrong and if so I'll stand to be corrected. I'll only be using short straps around the EP and secondary boss. If it gets to the point where I need a heated seat to sit on, I'll take up knitting by the fire :D 

    • Like 1
  8. 1 hour ago, SyedT said:

    Hi Daz,

    That seller would be me! I'm glad I could help with sourcing the scope; I always try to keep transactions smooth, whether I'm selling or buying. I went to the post office today and they are shut today for some reason (usually open until 12:30 today), so I will post it out before going to work tomorow morning.



    Haha! You're a top bloke Syed. I'm in no rush so don't worry. 


    If you buy from Syed, take it from me, he's trustworthy and keeps to his word. 

    • Like 1
  9. 2 minutes ago, SmokeyJoe said:

    First night out with my sw200 ,heavily light polluted city skies, no idea what I was doing, very rough polar alignment (I don't think you have to worry about that with a dob, never used one), pointed it at the brightest thing in the sky and there was Saturn in all its glory. Never forget that night. Brilliant scope.

    Sounds like a good start for you. I'm in rush to build the mount, and will do some technical drawings to get everything right, and a cut plan for the ply. I ordered one of those inclinometers and will use the compass facility on my iphone with it placed inside the dob base, so it'll help me get aligned. I'm not too bothered to get to use it due to this current weather!

  10. My Celestron came with the secondary dangling in the breeze, literally on the cup of falling off the adjustment bolt. You will need to get a collimation tool if you don't already have one, and as said above, it should (or you would like to think) be already set up perfect, but unless you check it properly it could be out, and give you bad views. I'd check it regardless. 

  11. On 24/02/2017 at 21:26, JOC said:

    Hi Daz69 you sound like an experienced tinkerer to me, I hope you end up with something that you are pleased with.  It sounds like it will give you similar views to mine and, although I haven't had much experience, I think I get really good views and I reckon you will be pleased with the results.

    I hope so JDC. I've started receiving some bits down for building my base, still waiting on some other small bits. Will probably start next Friday when I'm off for 4 days. It'll give me time to tidy the workshop and get set up for my machines to cut the wood. I'm really looking forward to using it. I'll likely use this just for obs, and will seek to use my 130 for imaging, once I read Every Photon Counts of course!

  12. I flocked my 130 and found a difference in sharpness or contrast whatever it's called (IMHO) so at some point I will do it. I've got to make dew straps because I just made my dew controllers :D  Mind you, now the weather has started to warm up, I'm probably a little late! 

    I know I've got a load of small polystyrene bits on the mirror as the sender had used the original box and packaging, and some of the polystyrene was not in great shape. It needs collimating as looking through the focuser, I can only see 3/4's of the primary. Besides, my idea of collimation might not be the same as the previous owner, and I can see that already. The 3 secondary adjusters were loose as well. Once I build my dob base, I'll do the collimation. I don't enjoy it, and I'm probably too finnicky about getting it spot on, but my 130 is so much better with good alignment. 

  13. My suggestion is thus: Stop using it or trying to rotate it if you've got a binding problem. If it's new contact the seller and explain the problem. they may tell you what the issue is and advise accordingly. If it's out of warranty, then it's down to you to sort it.

    If it's your fix, strip it apart, taking photos if need be as you go, place each item removed in the orientation that you removed it onto a piece of clean A4 paper, and inspect them once everything is out under a decent bright inspection type lamp. Then have a look at the mount itself. It may be that something like a piece of swarf is jammed in there against the shaft. 

    It should be easy to find the issue if you are methodical in taking it apart and good cleaning. If you can clean out any lubricant so everything is clean, then lubricate with new grease as you place buts back. Refer to a manual to make sure you don't lubricate something that shouldn't be lubricated. 

  14. What an impressive scope, and that's just me sat here looking at it! Lol, stood next to my 130, it's massive! Only issue so far is that the 2" - 1.25" reducer wasn't included, but the seller said he'll look for it, and if he finds it then he will post it on, can't say fairer than that. I didn't realise that it is a metallic black finish, looks ace. It came with the 9x50 finder and the dovetail bar, all for £120, bargain! Mrs Daz caught me sneaking it in, but there was no way that I was going to let this scope pass at such a cheap price. The mirror seems ok, but I'll remove it and give it a clean with a Brillo pad :D I'll pick up some distilled water when I'm out. Already got some Isopropyl Alcohol and organic cotton for a gentle clean. I buy this cotton in pads and use it in my vape machine to make my own coils and wicks, so I know it's organic without anything man made, like harsh fibres. 

    I've already ordered some bits to build my dob base, including some teflon sheet to cut the alt and azimuth bearings from. Will pop to our local charity shop and pick up an old LP for the box base, rather than use my scratch signed Def Lepard LP :)  I've got some adjustable cabinet feet in the workshop somewhere, and a selection of stainless nuts n' bolts in M4 - M12 sizes. 

    The next thing I suppose will be flocking it, and making a dew strap for the secondary and E/P. I'm looking forward to seeing what this scope is capable of.


  15. 51 minutes ago, orion25 said:

    Good question, Daz. I got a GoPro Hero 4 Silver and never considered using it for astrophotography. I may try some afocal shots of the moon or some other bright celestial objects in the near future. Please, post any shots you attempt. I'm curious!



    Could be worth a shot I suppose? Likewise, if you get any let me know too please. 

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