SingAstro

Hi richard, I guess the American is right.. if you connect the controller it will introduce noise to the Nexstar unless you have some passive filter on your controller. If the controller just connects to the battery it should not be much of a problem since the battery should not be introducing noise...

Hi Airconvent,
You can take a look at the heater system during the Mars watch. I will bring it along although I haven't made the heaters for my Quickfinder, 2 inch EP and for my dob's secondary mirror.

Hi,
You could consider getting a 45 degree diagonal as it would give a upright (normal) image. The astronomy 90 degree or 60 degree diagonals will give a MIRROR image. If you directly connect the eyepiece to the scope without the diagonal, it will give an inverted image.

Ya..12V won't kill but it is not nice to touch it... it will burn hehe; and if you accidentally short circuit it, it can burn up. I used a 17AH battery earlier cos I used the ratings used by Kendrick.. they claim that the current draw for the heaters are that high; 2A for 8 inch. Anyway, it is alway...

The current draw will be about 1A for such hot weather; tested with my C5 it it should be slightly less or about 1A. It also depends on how efficiently you can transfer the heat from the resistors to the scope. If there is no insulation to prevent the heat from escaping, then the current draw will h...

Hi rich, I think the Orion one should be ok; only thing is that you can't adjust the temperature. But if it is well optimized for the 8inch, then it should be good enough. I have a 17Ah rechargable battery (cost about 50 dollars with charger I think) that I bought from Sim Lim Tower. You could get o...

For parallel resistors, the resultant resistance is R/N where N=number of resistors. At 12V, EACH resistor(330ohm) will dissipate 0.5W of power. So. the total power dissipated = N*0.5 for voltage of 12V; note if your voltage is lower than 12V, each resistor dissipate less than its maximum of 0.5W. T...

Yup..those heaters on the market are really expensive. I'm using resistors as heaters for my DIY heating solution. I have a heater controller that allows variable heat to the optics. To make it variable.. you need to design a controller... and the controller has to be comprised with variable voltage...

Whats the meaning of the focal ratio of a telescope (eg. f/9)? focal ratio is the ratio between the focal length and the diameter of the lens (or mirror for reflector). focal ratio = EFL (effective focal length)/ Entrance Pupil (in this case diameter of the lens or mirror). Also there are mainly 3 ...

Hey Airconvent, my name is Lim Yang Beng... not Bing.. hehe. Yah.. I brought the C5 with microstar deluxe and my heater system to test that night. Actually it was the first time I was testing it outfield.. I tested it indoor by putting my cheapo EP in the fridge and taking out to condense but have n...