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About Luna-tic

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    Star Forming

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    sports cars, woodworking, astronomy, stained glass, shooting, reading
  • Location
    North Carolina
  1. I re-greased my AVX with Lubriplate 130-A. It isn't temperature sensitive (at least not within the bounds a human can survive or is willing to endure). It clings well to gears without being "sticky". I use it on the trigger assemblies and bolts of my semiauto rifles. https://www.lubriplate.com/PDFs/PDS/3_14-130-Series.aspx
  2. Very nicely done power supply, looks great and nicely laid out.. I just finished mine, will deliver 12VDC or 115VAC with included inverter. I'm using a 96 amp/hr deep cycle wet cell lead-acid battery. Very true. Generally, the heavier and more basic a battery is, the less it costs per amp/hr. capacity. As you go up in capacity, up in technology (AGM or Lithium)or down in weight, the prices climb correspondingly. Choose your priorities in weight, technology and capacity, then look at what's out there. As a very broad rule of thumb, you can figure it that way, but you can only count on about 80% of the total capacity to be useful, and that depends on several conditions. A 12 volt battery delivering 16 amps only gives you 192 watts, according to Ohm's Law, and that is at 0.75 ohms. You'd get 3600 total watts over 18.75 hours at that voltage and load. Now, if you were at 220VAC and drawing 16 amps, you be using pretty close to 3600 watts. A telescope mount of moderate size will draw anywhere from 0.25 to 0.75 amps during tracking. At full speed slew that will increase to 3-6 amps. If that is all you have to power, you can run most of the night on a 20 amp-hr. battery doing observation. I can run a dew heater at full power, my mount, a laptop and two cameras at less than 7 amps total continuous draw. So, for 6 hours, I'd use about 42 amp/hrs. Realistically, it would be longer than that, because the 7 amps is maximum, (during slewing) and drops about 2.5 amps during tracking. Part of the draw is from the inefficiency in converting 12VDC to 115VAC through an inverter, which part of my gear runs through.
  3. Glad you narrowed it down a bit. I was going to say there are a boatload of them across the big pond, which is, as you asked, west of London. If ever in the States, PM me and I'll treat you to ours.
  4. Generally, plan on about 80% usable capacity, max. Once you get to that point, the voltage starts dropping, and the mount will shut down from insufficient voltage. Also, with lithium batteries, the nominal voltage is less than a lead-acid battery, right at 12VDC, so any heavy draw will drop the voltage more quickly to an unsuitable level. If your mount draws 0.75 amps@12VDC, count on about 1.5 amps to account for slewing, temperature, reserve, etc., and select your battery capacity accordingly. Celestron's Power Tank Lithium is 17 amp-hours and will run my AVX about 4-1/2 - 5 hours on an observational night of moderate temps (battery capacity drops in cold weather). Most large batteries are rated by amp-hour capacity. It's all just a matter of math, volts X amps = watts; not hard to convert watt/hr to amp/hr and back, but if you assume 12VDC, as all our battery powered gear uses 12VDC, amp/hr is easier to figure duration by. The higher the amp/hr capacity, the higher the current drain necessary to drop the voltage under load, and the reverse is also true. A marginal capacity (for the need) battery will drop its voltage faster under a heavy load relative to the overall capacity of the battery. The current-draw rating of the mount spoken of by the OP is probably what it uses during tracking, and you can count on that tripling or more under high speed slewing. I just tested my EQ6R-Pro last night, as I have just built a field power system and was seeing what it was capable of. I have a battery minder that reads out volts, current and watts. My Skywatcher (with an Edge HD 8 mounted) tracks at 0.5-0.6 amps; under a go-to slew at max speed, it draws 3.5-3.7 amps, and curiously enough, as it slows to its "centering speed", it draws 4.1-4.2 amps momentarily before dropping back to 0.6 amps tracking. A night of observing will take more power than a night of imaging just to run the mount, and current use is cumulative. I had enough equipment connected to the system to draw around 10 amps; the voltage only dropped by 0.13 under the test load, from its nominal no-load of 12.9 VDC. That is with a 96 amp-hour deep cycle battery
  5. That one looks identical to mine, but mine goes by another brand name. I imagine they all come from the same factory in China. I did an all-up test on my system last evening. I hooked up my EQ6R-Pro mount, the dew heater strip (turned up full) for my C8 corrector, (both of those to DC connections), my DSLR with its AC adapter, and my laptop to AC power. The battery was at 12.9 volts no load when I started, slightly less than its 13V full charge. With all the above named gear running, voltage stayed at 12.32-12.45V, current load varied between 4-6.5 amps (current drain would go up about 2.75 amps when the mount was slewed), and was using a total of 54-56 watts, 10 of those coming through the inverter (it has its own watt/volt display). Total energy drain over the 15 minute test was 1.35 amp-hours. This bodes well for a long session, The only other items I might connect would be an EP dew heater, which would draw less than the larger corrector strip, and my guide camera. I could even run a second mount without undue load. Edit: It's interesting to note the amps drawn from the mount alone. While tracking, as one might expect, it's drawing 0.5amp or less. When it goes into a high-speed slew, as when you select a target and go-to it, current increases to about 2.75 amps, also as expected, but when the slew drops to its "creep mode" as it centers on the target, current increases to almost 4 amps before dropping back to the 0.5 amp tracking level.
  6. Easy enough to add, and in the plans. Hopefully, any apocalypse will wink out civilization so nobody has to suffer long. I'd much prefer a simple disaster like a blizzard or wind storm.?
  7. I just finished a field power system that will proved me both AC or DC power. The heart of the system is a 96 amp/hour wet cell deep cycle battery, so light weight wasn't on the priority list of features. It sits on a small dolly, so it can be moved relatively easily, but I wouldn't want to haul it across a field. I can usually take my cargo trailer within a few yards of my viewing spot, so it isn't a big deal. It will sit below the tripod, I can even strap the tripod to it to add stability. AC power is provided by a 1000 watt pure sine wave inverter, DC power is channeled through a RigRunner. There is a master power switch that shuts down everything and isolates the outputs for when I charge the battery. The system has a main fuse, and the inverter and each DC connection are individually fused. It has a battery monitor that shows volts, amps, watts and energy, and the inverter has its own monitoring panel and has a 5V USB port. The system has a secondary use as a backup power for loss of power scenarios in the home, to augment a small generator. The battery is contained in a box made of 1/2" plywood with a 3/4" pressure treated base, and is finished with a spar urethane, so it should "weather the weather" . Of course, rain would be out, but who sits in the rain with a telescope?
  8. 1-Level the tripod, then attach the mount, balance scope and attachments, input necessary time and location data, as for any session. Place telescope in Home position. 2-The HC will tell you the clock designation for Polaris. Don't worry if the time marks on the ring are upside down or at some angle; adjust the altitude and azimuth screws to place Polaris in the clock position indicated, assuming the top of the polar scope view is 12 o'clock. This will adjust the axes to the proper angle. The HC will also tell you your Alt-Az error once the polar alignment is done, so you can improve it if you want. I leave mine as -is, generally and am usually within 4-5 minutes of arc accuracy. Then I do a 3 star alignment. My go-to's usually have a star within the FOV of a 20mm EP. I assume the NEQ6R is same/similar to the EQ6R-Pro that I have. It sounds like the PS reticle is the same
  9. I found that the DSLR's screen is just too small for me to see well, even with a Bahtinov mask, I can't see the diffraction lines well enough to determine a good focus. (I'm also getting older) I bought an accessory 7" screen that plugs in the HDMI port on my DSLR. It has a hot shoe mount that allows attachment to the camera, although that doesn't work well for telescope balance, and also comes with a gizmo that allows strapping the screen to a light bar (made for professional photographers). It works well clamped to a tripod leg. The screen has quite a few functions that work well for AP. The one I like is a focus function, it puts a fine red line around the screen subject when it is in focus. The screen will show anything bright enough to be seen in the camera's screen, it is a 1920x1200 pixel resolution. The screen is battery operated, has its own battery on back that removes for recharging, and it will last long enough for a good imaging or viewing session at night. I sometimes use it at outreach sessions by installing the camera on an EP (or use it prime focus) and viewers can see the image on the screen rather than having to squint into the EP. Works great for young kids who want to grab the scope. The screen backlight can be changed to several colors, including a red screen, and has a light shield that helps block any glare for other observers. The screen is fairly bright, so I usually hang a small dishrag over the screen shield so it doesn't ruin my or others' night vision.
  10. You can get by with the AVX using a longer focal length, but you'll need good guiding to get decent results and will work harder to get them. I like my AVX a lot, and started out using an Edge HD 8 (2000mm F/L) with it. I've since bought a heavier mount to use for AP, and the AVX is primarily my visual mount now, although if I have the Edge set up on my EQ6R Pro and want to get a widefield shot without changing things around, I'll put my shorty refractor (478mm F/L) on the AVX and get great results. The stiffness in the RA lies at least partly with the grease used. I disassembled my RA and Dec, cleaned all the grease out, and re-greased it with Lubriplate 130-A, and while it still doesn't spin like a ball bearing does, it is much 'looser' than before. The mount doesn't come with a polar alignment scope, and rather than get one later, I'd recommend saving for a Polemaster; you'll get an easier and more accurate PA. The ASPA or 3-star/calibration star alignments do very well, or you can opt for Starsense.
  11. Referring to the picture of the worker out on the dish; you can see the dish is made up of many individual panels. There are, in fact, 2004 of them. The dish is an "active" surface, meaning it can change its shape to compensate for expansion, contraction, and sagging in order to maintain its highly tuned parabolic shape. There are 2209 actuators under the panels that move the panels to keep them aligned. The panels have a surface accuracy of 50 micrometres; the scope can operate at frequencies between 290 MHz and 100 GHz.
  12. As promised, a few pictures while on the telescope during the tour. 1st picture is a worker out on the dish, you can see how large it is. 2nd picture is at the dish level, looking up at the underside of the array platform, which is 325 feet up. 3rd and 4th pictures are from the array platform. It's still another 45 feet to the secondary reflector, but it can only be accessed by climbing the structure. The telescope in the distance is the 140 foot telescope. Last picture is the base of the telescope, not the size of the trucks below it. A couple of interesting notes about the 140 foot radio telescope. It is on an equatorial mount, one of the largest ever built. The RA bearing is the largest ball bearing ever manufactured.
  13. English is my native language, and you're doing a better job than I do most times.? Of course, I live in the US South, so our English can be a little.....different.
  14. I'm beginning to think the same thing. It works well when it works, but I've found it to be occasionally inconsistent. Some nights I get perfect star alignment, some nights I think it's on a different planet than I am. Most times are okay. I had purchased the Celestron Starsense before getting an EQ6R, and had wondered about inter-compatibility between the brands. It was quickly apparent that the connector for the hand controls was not compatible between brands, and I was somewhat disappointed I couldn't use the Celestron Starsense on the Skywatcher mount. However, when I saw how accurate the go-to was on a 3 star alignment with the EQ6R, I quit thinking about it. As for the AVX mount, doing a 3-star alignment and a couple of calibration stars doesn't take that much longer than using Starsense, and I get as good accuracy, so I've sort of parked the Starsense in its box for now. I'll keep it for a while, but may sell it at some point.
  15. The trade-off is price vs. weight when buying suitable battery packs. OP could go with the Powertank Pro Lithium, its a 158wh (translates to 13.16 Ah at 12VDC) Lithium Iron Phosphate (LiFePO) which weighs 4.5 lbs., but costs over twice what the standard power tank costs. I would have suggested the Powertank Lithium as a great match for his mount. It's smaller than the Pro, has 86.4wh (7.2Ah) and only weighs 2.25 lbs. I use one with my AVX and it will power it for a long night or two short ones. It's smaller than Foster's Lager oil can. I figured the OP was looking for something more economical. I use one of those car starter setups like cletrac shows to run my EQ6R, it'll power that mount for 12 hours with frequent slewing.
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