Perkil8r Posted July 4, 2012 Share Posted July 4, 2012 Not much doing at the minute, and notice that FLO are having a sale of astrozap stuff. With a newt, how do you go on? Do you just put one band around, if so where? Near the open end close to the secondary, at the bottom near the primary or in the middle? Which works best position wise? Or do you use more than one? I'm talking just the OTA here, not EP's as well or finder etc. Link to comment Share on other sites More sharing options...
Daz Type-R Posted July 4, 2012 Share Posted July 4, 2012 Hi. For purley the OTA (then by that you mean the primary and the scecondary) you just need a dew strip as close to the primary mirror as possible, so it will be down the bottom end on the outside of the ota and a dew strip actually around the stalk of the secondary mirror held in place with some sort of insulating foam etc or on the back of the secondary mirror. There are currently no strips that will 100% fit round the back of the mirror on a 200P (trust me I have looked). See my signature for my dew control methods (still work in progress), for the secondary I am making my own (with Martyn's help) as no product out there will fit directly. Hope that helps. Link to comment Share on other sites More sharing options...
Perkil8r Posted July 4, 2012 Author Share Posted July 4, 2012 So presumably the heat then fills the OTA preventing the secondary from dewing up as quickly? Never had a problem yet with the Primary dewing over, just the secondary and EP's. Link to comment Share on other sites More sharing options...
Daz Type-R Posted July 4, 2012 Share Posted July 4, 2012 No, you do not want any heat in the OTA, that is why you attach the heater strip or whatever to either the back of the mirror or the stalk and then cover it in insulation foam so the heat is directed into the stalk or the optics and NOT the OTA. This applys to the secondary. By attaching the heater strip to the outside of the OTA for the primary, it gently transfers the heat to the cell without heating the inside of the OTA. I have issues with my Telrad, Finder, EP's and secondary, I have not bothered with any primary heater stuff. Link to comment Share on other sites More sharing options...
Perkil8r Posted July 4, 2012 Author Share Posted July 4, 2012 Right, gocha... so what's the best way of dew prevention for the secondary? Link to comment Share on other sites More sharing options...
Daz Type-R Posted July 4, 2012 Share Posted July 4, 2012 For the secondary use the method as described above or you could try a dew shield ( will prolong the formation of dew on the secondary but will not stop it). The other cheap option is a hair dryer, but I doubt the neighbours would appreciate that at 2 in the morning. Your mirror dews up, quick blast with the hair drier until it is clear. Link to comment Share on other sites More sharing options...
Perkil8r Posted July 4, 2012 Author Share Posted July 4, 2012 So in short then, I need a big band around the primary end of the OTA, the heat will then transfer up via the tube. Pop a dew shield on for belt and braces and the job should be a goodun? Link to comment Share on other sites More sharing options...
Daz Type-R Posted July 4, 2012 Share Posted July 4, 2012 (edited) No. The heater strip round the bottom will prevent the primary from dewing up but it is allmost unheard of for the primary to dew up, but it can happen. You need heater pads / strips as described above on the secondary to stop the seconady from dewing up. A dew shield is just an extra bonus, but will proberbly not be needed if you are fitting a secondary heater system. So what I think you will need is....... 1. Dew controler - regulates power to the heater strips. 2. Some sort of heaters to apply to the secondary. 3. Heaters for ep's, finders, telrads etc etc. 4. Dew shield which will double up as a stray light preventer as well. (nice extra to have but not essential) Edited July 4, 2012 by Daz type-r Link to comment Share on other sites More sharing options...
Perkil8r Posted July 4, 2012 Author Share Posted July 4, 2012 Oh right read it again and sussed what you mean, I read it wrong before. So I need quite a small dew band then. Does the wire not interfere with the light path? Link to comment Share on other sites More sharing options...
Daz Type-R Posted July 4, 2012 Share Posted July 4, 2012 You have to tape it along one arm of the spider veins and either drill a small hole throught the OTA so the cable can get to the dew controller or just tape it round the edge to the dew controller. Link to comment Share on other sites More sharing options...
Perkil8r Posted July 4, 2012 Author Share Posted July 4, 2012 Superb, I'll have a look see what size I need and get one odered asap whilst the offer is on. Link to comment Share on other sites More sharing options...
Daz Type-R Posted July 4, 2012 Share Posted July 4, 2012 Are you looking at these...... />http://www.firstlightoptics.com/dew-prevention/astrozap-dew-heater-tapes.html Also what were you thinking to control the heat distribution, something like this... />http://www.firstlightoptics.com/astronomy-cables-leads-accessories/hitecastro-four-channel-four-port-dew-controller.html and have you got your power requirements? Link to comment Share on other sites More sharing options...
Brantuk Posted July 4, 2012 Share Posted July 4, 2012 For a newtonian I would consider a small fan on the back of the primary to blow cool air up the tube. It helps keep the mirror at ambient and cools the tube a lot quicker. A small dew heater or pad on the secondary as Darren describes is ideal - used with a dew shield you're guaranteed a dew free night in all but the heaviest conditions. You can also run an eyepiece dew band at the same time if you are using the same ep most of the night. Link to comment Share on other sites More sharing options...
Perkil8r Posted July 4, 2012 Author Share Posted July 4, 2012 they should do pads to go with them for gloves and shoes, all powered off the same controler Link to comment Share on other sites More sharing options...
Brantuk Posted July 4, 2012 Share Posted July 4, 2012 Oh they do heated shoe inserts and warmed glove (like the motorbike ones) as well as heated coats - check out FLO's clothing section. But the battery packs are all sewn in or strapped to legs and wrists etc Link to comment Share on other sites More sharing options...
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