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About MarkyD

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  2. This one and there are loads more
  3. You need to remove the red bung pronto. Why didn't you run the all of the Negative cables to the battery terminal rather than have a floating join with the screw. They also look like 40A fuses (Orange) and I would have run a thicker cable from the Battery + to the fuse box Other than that it looks nice and easy to use
  4. This was taken with a 200P-DS and Canon 1D MkIII (Whirlpool Galaxy)
  5. 0.75 meters is deep enough for SWA. Lay a bed of sharp sand in the bottom, lay the cable then another layer of sand. Run a length of yellow danger cable tape over or even better use some of those roofing tiles you have to the side to cover then the tape. Then back fill. Make sure you leave far more cable at the ends than you think you will need as mistakes will be hard to rectify
  6. The connectors are rated at 5Amp so will be OK. For the current draw take the wattage of the dew bands and divide by 12 to get the current I(amps) = W(watts)/V(volts) ie. for a 20Watt band I = 20/12 I = 1.67Amps at 100% power The canon, and guide cam will take little current so allow 0.5A for each as a safety net. The manufacturer may have the specs for the focuser. Worst case is when stalled as this will ramp up the current momentarily. The HEQ5 specs say 12V 2Amp so allow 3amp to be safe. I would also add a few amps on top for future additions
  7. To calculate what Ah battery you will need you need to know the current draw of all your equipment. You can then approximate how long a battery will last from a full charge A 12Ah battery will supply 12amps for 1 hour, 6 amps for 2 hours, 3 amps for 4 hours and so on. The time will be shorter than this due to loses I use screw lock audio connectors for my equipment available from Maplins A battery is self regulating. If all your equipment can handle up to 14.5 Volts which they usually can if designed to connect to a 12V battery. 12V is listed as the nominal voltage. 14.5 is max voltage when fully charged but very quickly drops under load. If any equipment uses less voltage ie. 5V you will need to drop the voltage. A switched mode regulator is more efficient but some stuff doesn't like PWM power. A linear regulator is clean but loses alot of power in heat to drop the voltage Any charger designed for the type of battery will do. My solar kit uses an MPPT charger. My bike uses an Optimate
  8. I use this void/subroutine on an Arduino. If you can make sense of it. The whole code measures ambient humidity and temperature and the temperature of the specific sensor (secondary mirror in this case - DB18B20 stuck to the rear of the mirror). The dew heater is usually powered at 10 - 20% power for most of the time so the mirror never gets to the dewpoint int getpwr( float channeltemp, int trackmode ) { int pwrlevel = 0; if ( trackmode == DEWPOINT ) { if ( channeltemp >= (dew_point + 6.0 + dewconfig.offsetval) ) { pwrlevel = 0; } else if ( channeltemp >= (dew_point + 5.0 + dewconfig.offsetval) ) { pwrlevel = 10; } else if ( channeltemp >= (dew_point + 4.0 + dewconfig.offsetval) ) { pwrlevel = 20; } else if ( channeltemp >= (dew_point + 3.0 + dewconfig.offsetval) ) { pwrlevel = 50; } else if ( channeltemp >= (dew_point + 2.0 + dewconfig.offsetval) ) { pwrlevel = 75; } else pwrlevel = 100; } else if ( trackmode == AMBIENT) { // assume trackmode is AMBIENT if ( channeltemp <= (tval - 9.0 + dewconfig.offsetval) ) { // is the OTA temperature way below ambient pwrlevel = 100; // then set the pwr level to 100% } else if ( channeltemp <= (tval - 7.0 + dewconfig.offsetval) ) { // is the OTA temperature 7 degrees or less below ambient pwrlevel = 75; // then set the pwr level to 75% } else if ( channeltemp <= (tval - 5.0 + dewconfig.offsetval) ) { // is the OTA temperature 5 degrees or less below ambient pwrlevel = 50; // then set the pwr level to 50% } else if ( channeltemp <= (tval - 3.0 + dewconfig.offsetval) ) { // is the OTA temperature 3 degrees or less below ambient pwrlevel = 20; // then set the pwr level to 20% } else if ( channeltemp <= (tval - 1.0 + dewconfig.offsetval) ) { // is the OTA temperature 1 degrees or less below ambient pwrlevel = 10; // then set the pwr level to 10% } else pwrlevel = 0; // if ota close to ambient then pwr level to 0% } // end of if trackmode else if ( trackmode == HALFWAY) { // assume trackmode is MIDPOINT if ( channeltemp >= (tval - (((tval - (int)dew_point) / 2) - 0) + dewconfig.offsetval)) { pwrlevel = 0; } else if ( channeltemp >= (tval - (((tval - (int)dew_point) / 2) - 2) + dewconfig.offsetval)) { pwrlevel = 20; } else if ( channeltemp >= (tval - (((tval - (int)dew_point) / 2) - 4) + dewconfig.offsetval)) { pwrlevel = 50; } else if ( channeltemp >= (tval - (((tval - (int)dew_point) / 2) - 6) + dewconfig.offsetval)) { pwrlevel = 100; } else pwrlevel = 100; // its lower than midpoint - 7 } // end of if trackmode else pwrlevel = 0; // set pwrlevel to 0 if there is an unknown tracking mode return pwrlevel; } Credit to Robert Brown for this snippet of code Here is the idea I heavily modified for my own needs to include intervalometer, LCD touch screen, voltage monitors etc contained in one box all running on a Mege2560
  9. You can use the same terminals to power and charge. You can use 4mm banana plugs and panel mount sockets or I use these for my connections rated at 5A
  10. Minimum IP rating for LV (230V) outdoors is IP44. You will also need it to have 30mA RCD protection either at the CU or on the socket it is supplied from but not both
  11. Any grease that isn't rated for low temps in the mount gears/bearings will thicken and could put strain on the steppers and running gear. Wrap the mount in a thermal liner to keep some heat in
  12. If you want reliable LiPo at that size this is the place to get them from. You will also need a charger for this (designed for LiPo's)
  13. Looks the same scope as the NEQ6 so M3 will be the ones I get all my fixings from here (mainly for my RC stuff)
  14. There was recently released a new 3d image of The Pleiades. I think it was on Sky at Night in December.
  15. Looks like dust bunnies. They crop up quite alot. You can clean the sensor in the camera with a cleaning kit. I use a rocket blower and carbon lenspen to clean mine but there are others like wet wipe kits about Usefel info on cleaning sensors