Cabling

Recommended Power and Video Cable Accessories

Power

Most video cameras and the IOTA-VTI use 12 volt DC power (12 VDC) with a center positive 5.5mm/2.1mm power connector.  Powering everything with an 110V “wall wart” (or other AC based power supply) works fine but many observers prefer to use a battery since there is less chance of noise coming through from the AC power input.  Some observers use 12V car or marine batteries but you don’t need that much reserve power in most situations.  So many observers use a simple pack of eight AA batteries.  Standard NiCad AA batteries will power a camera + VTI for a couple of hours.  Rechargeable NiMH AAs will last much longer – six hours or longer.  And Lithium AAs last the longest (8 hours) but they are expensive.  NiCad have problems in cold weather so keep them warm.  NiMH do better in the cold and Lithium are best for cold weather.  You could also use one the many 12v DC power sources made for powering telescope mounts (e.g. the Celestron PowerTank).

There are many ways to build-up a AA battery pack.  Here is one option using two pieces:

For simple outings some observers will use the 12V DC jack from their car.  If you use this option be careful that you don’t run the system long enough to drain down your car battery.  You can find 12V extension cables and 12V cigarette lighter to 5.5/2.1mm cables online.

Since multiple pieces of equipment use 12V power you will probably want a 5.5mm/2.1mm power “splitter”.  There are a variety of sources online (Amazon and elsewhere).  Just be sure to get the right combination of male/female – generally you want one female to multiple male connectors.  Since the camera will be attached to the telescope, you will probably also want a 5.5/2.1mm power “extension cable” to separate that connection from the rest of your equipment.  And once again, check the connector on your camera to get the right combination of male/female for the extension cable.

Some equipment requires 5V power (typically from a micro USB connector).  Once again you can use the small 5V USB power supplies for this equipment.  Or you can use batteries – the rechargeable “cell phone battery packs”.  Anker makes several good models and so do many other manufacturers.  A 10,000 mAh version is a good size (roughly $20 at this time).  We are researching options for generating 5V USB power from AA batteries and will post something to this page when we have a good option.

Video Cabling

Most cameras and VTIs using standard RCA connectors for the video signal connections.  RCA connector video cables are widely available.  We recommend that you choose cables that provide enough length to reach your equipment but don’t burden your setup with overly long or bulky cables.  Some video cameras use a BNC connector.  You can find BNC to RCA adapters online or possibly at a local electronics store.  Here is one example: RCA/BNC Adapter (10 pack).

If you need to use a “video splitter” (e.g. y-cable) in your setup, be sure to use one that includes a signal amplifier (to avoid degraded signal quality).

Miscellaneous Accessories

All of those cables can turn into a mess.  We recommend that you keep your gear organized in some sort of box or container with most of the cables attached a ready to go.  For the longer cables, we recommend that you use some sort of cable tie to keep the cables neat when they are stored (Velcro works well).

Page history:

2016-Aug-16: initial version.