This is the first time I have used Ha filter, The moon was high, I tried 10 min exposures, but the stars were not so round. I then did 4 x 8 mins, had planned more, as all my power went down, & Cygnus had gone into a tree by the time I had gone onto mains power.
I tried to process but there are not enough images, so this is just stacked. Not sure what went wrong, I have the laptop & SX connected to the car battery & suddenly the laptop had no power. The SX had played up a bit with stripes on a couple of images & the darks had light jagged lines across the tops, looking like mountain peaks. Wondering if it was to do with power. I only hope that I have not let the battery go too far down.
Fay
(http://farm2.static.flickr.com/1261/1238276315_015b51a984.jpg)
This does not look too good on here, so will try to do something with it.
Fay
Not bad Fay. It was a murky night last night so that may well account for the noise. Maybe shorter exposures would have been better on this.
Thanks Mike, do you have to do L images as well when using a Ha filter? Or just the Ha?
The image looks better on the laptop, I will have a little play around, but not sure if I was doing too much, bringing out a lot of noise, or if it is the spread of the nebula.
Fay
Well done fay, I would suggest getting upto 10-15 minute images this target is hard.
But its better than my first 3 attempts :-( they we're awful so this is impressive.
Thanks Chris, I may have another go tonight. Hope you don't put one of your master images on today!!!!!
Fay
QuoteThis does not look too good on here, so will try to do something with it.
Hi Fay,
I'm not yet this far advanced with DSO's, but I'd be well happy with an image like the above.
It can only get better, so keep up the good work.
Tony G
Thanks Tony. I wanted to do more exposures but all my equipment closed down. I am thinking it is a loose connection to the battery. The battery is ok as I had it tested at Halfords today.
I set up again late yesterday, power went again & by the time I had it all connected to the mains, & spent time trying to figure out what was wrong, the guiding went up the spout! I think that particular problem was.................. I had forgotton to look up all night & when I did it was really cloudy, so guide star had diminished.
Knit one purl one, knit one purl one.....................
Fay.
Hi Fay,
This looks good to me.. you are starting to get very critical with your imaging..:-) Any DSO with a full moon is a great shot - I've limited experience with an Ha filter & have always struggled to get good images with it (probably because I can only do about 2-3min subs with my camera before ampglow gets too bright) - I think Chris is right the longer the better with an Ha filter....
WRT to your battery - your laptop draws about 4 to 5 Amps at 12V & your SX probably another 2A with cooling etc. so you could be drawing in the range of 7A at 12V - if your car battery is rated at say 75Ahr (like mine) then in theory you could run the laptop & SX for 75/7 or approx 10hrs.. in reality you should probably only discharge the car battery to about 1/4 of its capacity so lets say 7.5hrs... If you think about it this would only be about 2 nights of imaging before you need to recharge... If you are planning a long or important night of imaging then I would recommend charging all your batteries ahead of time...
Hope that helps - John
Thanks John,
The problem with those car batteries is, you would have to guess if the power was getting too low, as there are no indicators. I thought I had used so much power that it was now unchargeable, luckily I was wrong in this aspect.
Obviously, the best thing is to charge after every evenings use.
Fay
in general, car batteries are designed for constant float charging and occasional high current, short duration discharging. I have mine permanently connected to a solar panel and charge controller to keep it topped up. The charge controller is only there because the solar panel is large enough to overcharge the battery, but one of the small panels sold for caravans and boats will keep it topped up, even if it's not meaty enough to charge it. Otherwise a charger that is designed to be permanently connected to a battery can be used.
The alternative is sulphation, where sulphate crystals form on the plates reducing capacity and ultimately shorts between them, killing the battery completely. A car battery left uncharged for several weeks can sulphate enough to have a noticeable reduction in capacity.
I thought I was the anorak, Ian you have surpassed even my standards :o
Chris your only an anorak when it comes to discussing 'well depths' & spectroscopy.....
That's why I did not answer Thanks anyway Ian
Fay
Got any specific recommendations for solar-chargers etc.?
If you want some good solar chargers go to the boat show - great place for stuff like that.
Quote from: csuddell on Sep 05, 2007, 16:19:27
I thought I was the anorak, Ian you have surpassed even my standards :o
Kettle, you're black, love Pot. :P
I'd take Mike's advice. They about £20 in Maplin at the moment, but that's expensive and they often appear in their sales. I've got one big enough to charge the battery, but then I'm planning on only having 12V in my shed and everything's going to run off of that.
The other thing to watch out for is that car batteries (leisure batteries less so) really don't like being deep discharged. However, if your battery is large enough that shouldn't happen for our purposes.