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Ships and Stars

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Everything posted by Ships and Stars

  1. Nothing interesting! You like astronomy man! Welcome.
  2. PS - a wheelbarrow attachment will make life much, much easier with a big dob with fewer visits to your GP. Moving the 500p around by taking the mirror assembly off the base is still a proper chore and eats into my viewing time. It's not so much the absolute weight, it's the way I have to lean forward to carry it due to the bulk and worry of tripping with the mirror, argh! Worst nightmare. A skyliner should take a wheelbarrow attachment quite easily. I'm still trying to sort one for the Stargate, but work has been full on. I'm surprised no one seems to have come up with a wheelbarrow attachment for the Stargate yet. It needs it. Some blistering views of the heavens however!
  3. Hi there, if you are able to shift a bit of weight around and have a car/van with a little room for the odd visit to dark sky sites, I'd go for the biggest dob possible within reason and budget. Why not? I bought all my gear used, but it took a lot of waiting and watching for various bits to come up. Had I bought new, I would have ended up with a much smaller scope (which I do have - a 130PDS and a 20" Stargate dob, no middle ground here, haha). I came from a photography background, so wanted to take a break from stressing about exposures etc and just enjoy the views, so dob it was. Anyhow, in my brief experience, a dew heater for secondary - yes, yes, yes. Raising the scope - buy a huge one so you don't have to! Shroud - if a truss dob, a definite. 2" eyepieces - sure some are insanely expensive (21mm Ethos, I'm looking at you) but on the other hand the TV plossl line is great for the money I think. Lots of other options. The base - try epoxy resin used for wooden boat building. Non-toxic, no VOCs, super durable. Used - old dobs might need mirror recoated. Focuser - mine is fine, but it will have more weight hanging from it this autumn, so might upgrade. If you are not in a hurry, just keep an eye on the second hand market, or put a wanted advert out there? Happy dob hunting!
  4. I'd love to sit down and observe. One of the drawbacks with my big dob, but I have a 130p on an AZ4 mount which I could probably sort out a chair for. I tend to wobble a bit looking though the big dob after some time, have to stop and regroup, haha.
  5. Ah ha! Now we're talking. Good idea there. I've a 2" 2x barlow, stuck a Baader click lock 1.25" adapter on top for quick changes if I'm using 1.25 eyepieces. Sounds like you have it under control!
  6. PS the excellent suggestions above regarding trying different scopes at a club event is a great idea as well...
  7. 10" dob all the way! Should be best bang for the buck, especially under dark skies. Big scope, but still portable. Dead simple to use, no tracking or goto stuff to mess with, just use sky safari etc to get an idea for your target and star hop manually to your destination. Collimation is easy once you've done it a few times. These come up frequently second hand as well in good condition.
  8. Just to confuse you a bit more, ha, if you buy the Vixen 15mm, you'll have a really good all-around eyepiece for that size scope, and simply adding a 2x Barlow will give you a 7.5mm for planetary without too much magnification for most decent viewing conditions. I think jumping from 28mm to 9mm leaves a big gap right in the sweet spot of the scope's magnification range. A 15mm or 17mm eyepiece and a 2x Barlow would slot in there nicely. I think I paid £30 for my quality Barlow second hand and it doesn't degrade image quality. But I'm sure the 9mm is good too!
  9. I'd maybe go for something in the 12mm range which is around 80x on that scope I think. If you have a 2x Barlow then you can of course double the mag to 160x or so for good conditions. I've been wanting to try the Baader Morpheus line, they've great reviews except the 14mm which is mixed. But this is pitting the Morpheus against best offerings from Televue and Pentax, so the Baader is relatively cheap in that regard (still £175). I'm sure the Vixen eyepiece Steve mentions above is good. Above the really cheap starter eyepieces, most eyepieces seem to offer generally fine views. The 28mm SW 2" eyepiece is surprisingly good, especially considering they practically give them away!
  10. Thanks David, shall give it a go. I have a digital multimeter that measures DC amperage but no oscilloscope. You are correct, the red & black wires run to the smaller PBC, didn't show a photo of them both together. If I get lucky I'll let you know!
  11. PS: the L3 coil/inductor thingy looks burnt on the left side, but it's just the sun reflecting off the resin...
  12. Finally, what I believe is possibly the charge controller? It's a separate unit off the main red and black wires. I uploaded these as 3 posts so the image file could be as large as possible. 3000px on the long edges. Cheers
  13. A simple fuse would be lovely! I've included some slightly better photos, incl reverse side of circuit board. I know I'm probably better off time-wise just getting another battery, but I'd love to be able to fix something on this level so may put a little time into it. One other thing I forgot to add is that I have a Nitecore i4 Intellicharger for my 18650 LED torch batteries, and it says it also accepts up to the 26650s. I believe it has a built-in test circuit, but might try and charge them individually that way. It also has a safety cut-out for overheating/overcharging apparently. Will reread manual for the i4 charger. Thanks again! If I get lucky and fix this, I will let everyone know.
  14. Hi Julian and David, Many thanks, there's some good information in here. I have a bit of testing to do! The IC and R100 I believe both show simple resin discolouration, but I'll investigate around there again. I'll also check the transistors/ICs. Hoping it was something simple, but a close inspection of both sides of the circuit board (sorry, no reverse pics) didn't reveal any obvious signs of overheating or cracked solder. Oxidation or corrosion isn't a problem as it's practically a new unit. I shall persevere a bit more on this, but may end up buying a simple 12v lead-acid battery or running a power lead from my van's 105Ah leisure battery, providing the voltage drop isn't too great (i.e. use the proper gauge wire and fuse it). Fingers crossed and thanks for all the info!
  15. Hi all, Anyone good at circuit board testing/repair or know what pops first on a Lithium power pack PCB? Batteries are fine and holding voltage. Background: I received a new Celestron Lithium LiFePO4 7.2Ah powertank with my scope when I bought it second hand, was really happy the seller chucked that in. However, there was no charger with it (it was a 16V charger, and I couldn't find one online anywhere and the seller could not find his) so I tried a 17.5V charger under carefully controlled conditions in a safe area in case of explosion or fire. NO problems. The voltage/amperage should have been within what was generally accepted range for this type of pack, albeit at the high end. Anyway, I used this charger very carefully about five times, no overheating, etc but after charging it for about an hour one day I noticed the LEDs had stop emitting and I immediately disconnected it. Now the circuitry has a short somewhere and the tank won't power on, but the eight 26650 batteries - wired in series in two banks of four - are fine and holding voltage, no leaks etc. I've tested the coil and can see no damaged/melted solder, except at the base of the main copper wire coil, but this is probably from the manufacturing process as it's the largest area of solder requiring the most heat. Given that these batteries can be very dangerous if they explode, I'll probably dispose of it safely and buy a new power tank, but hate to chuck it for a 10p resistor, etc. I'm ok with soldering etc but no electrical engineer. Ideas? Cheers all
  16. That's what I was initially thinking, but didn't want to have to tilt it very far. A four wheeled truck would still require lifting the assembly on top. If I find some suitable box section perhaps I could run that underneath, but need a way to keep it from slipping out, unless I bolt both runners together. I've two weeks off in September so will have to make something soon, unless I stay in the same place, but will probably be chasing clear skies, haha.
  17. Hi all, I'm looking to add a wheelbarrow attachment to my Stargate 500p dob base so I can roll the mirror and GOTO cradle assembly as one unit into the back of my van with some heavy duty loading ramps I bought this summer. Otherwise I have to disconnect the GOTO drive cable, remove the counter weights, split the mirror unit from the cradle, load one section at a time, then the reverse on site, plus rethread and retension the GOTO cable which takes some doing at night. Loading this as one unit and rolling it out onsite is a massive timesaver and definite back saver. Probably in the 70kg range for the base unit and mirror, plus counterweights, and very bulky. This way I just need to pop in the truss rods and tophat on site and I'm basically ready. Problem is, the Stargate assembly has no obvious attachment points for a fork and would need to pass under the entire rig, versus a traditional dob mount with forks on the side. Any ideas? I wanted to weld a bracket underneath but the material looks cast, so that's above my pay grade. I though about removing the feet and replacing them with wheeled castors, but I need to use 10" or preferable 14" pneumatic tyres, otherwise it will be too harsh to roll around. Has anyone tackled this? Any and all ideas welcome! (within reason, haha) Clear skies all.
  18. How are you collimating? Cheshire for secondary and laser for primary? Or something like that? Other thing might be the Baader CC isn't fully correcting coma. I'm not sure on either of these, but they are the primary suspects in my mind. Curious to hear what more experienced people here think.
  19. Not to drive you crazy, but I'd go for a used one if you can find it, much more scope for the ££ after depreciation. I'm in NE Scotland and have a 20" SW Stargate 500p dob I bought as new, never used, for a very substantial discount. The previous owner became ill and could unfortunately no longer set it up. I started off looking at 10-12" dobs, but aperture fever took me early on, haha (my first real scope!). I think the SW truss rod dobs are quite portable for what they are (the 18" & 20" Stargates) but at the end of the day, they definitely aren't light either! Transport is another issue. I've used it at home, mainly lunar, but loads of LP here right where I live and very obscured views of the sky, versus excellent skies no too terrible far away. I've a van and bought some aluminium loading ramps so I can cart the mirror+cradle assembly into the back in one piece with the drive cable assembled and ready to go. Once that's rolled out and on the ground, setup and takedown is fast, a matter of minutes generally to install and remove the truss rods and tophat (is that what it is generally called, or am I making this up!?) , even in the dark. I generally don't use the truss braces as it's very rigid once things are tightened down, unless it's going to be parked in the same place for some time or I arrive to my dark sky site early. It requires collimation each time, but it's fast and simple enough to do. I've only been out with it a few times in the late spring, so waiting for true darkness to arrive once again. August 12th is when proper viewing season starts again here. I've booked two weeks off work in Sep, can't wait, will be driving around Scotland chasing clear skies, fingers crossed, not too far from home. Anyway, having said all of this, a 12" or 14" solid tube dob would be great from a portability standpoint. If you put the word out, a second hand one might come your way for a great price. Otherwise, if you have the cash and don't want the hassle of chasing one down, then a shiny new one sounds nice as well. Good luck and clear skies, let us know what you end up with.
  20. I also have the 21mm and 13mm Ethos, I'll definitely be keeping the 21 but might 'possibly' be letting go of the 13mm, I'll use them some more when things get a bit darker and see how I get on with it. I never thought I'd sell an Ethos! I've been wanting to try the Delos - I have a 9mm Delite but a little more FOV would be nice. Then again, the Leica zoomed in to 9mm offers this! I really enjoy the zoom, must admit. Money well spent.
  21. I do like a large FOV at first, then I dive in... I use the 55mm plossl in an f4 scope to locate things, but damn it's good. It has an exit pupil around the size of a high school trampoline, but honestly, from what I have seen, it is so so sharp. Just amazing.
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