M81 and 82 Revisited

A nice clear night and an opportunity to image from a friend's home north of the city lights produces a pretty picture:

 

This is based on 44 x 3m light frames with 15 dark frames, Canon T2i at ISO 800 on a TV-102 at f/7.

Power saving update: the software I talked about that turned off the laptop LCD display wouldn't keep it off. Apparently something about using ImagePlus kept turning the display back on. This wouldn't be a problem if a hand control was used to run the DSLR and images were stored on-camera.

Battery Update: I ran the laptop (fully charged), dew prevention, mount and camera from the 35Ah battery for four hours; loaded voltage fell from 12.7 (unloaded, 13V)  to 11.8V. Unfortunately I popped the battery onto the charger as soon as I got home and didn't check its final unloaded voltage.

Assuming it was 12.1V it would have been at 50% capacity, meaning it would have supplied about 17Ah or about 4Ah per hour. This is about right if I take into account that the old laptop battery was in place and it could run the laptop for maybe two hours, after which the 35Ah battery was supplying 6A to both run the laptop and recharge its battery.

That's a whole lot of assumptions and guesses, though, so it doesn't mean much. I may end up rewiring the battery box to include an ammeter so that I can monitor power use more rigorously.

M81/82/NGC 3077 under bright skies

Last week I was in another ALBN gap with nothing but large, very dim targets to image, and a nice bright gibbous moon to ruin any chance of actually doing that.

How about a nice bright Galaxy? Too windy, you say? Then use something short like an AT65. Which is what I did:

NGC 3077 (lower left), M81 and 82--you already know them

I don't think that my skills are up to battling the light. This had a terrible sky gradient that had to be removed. Shooting into sky over a city will do that, I suppose. There were also quite a few satellites that crossed the light frames, also. Do I sound like I'm making excuses?

What I learned is that I'd like to go back and image NGC 3077--it has an interesting core. Longer focal length and darker sky!

This next week is forecast to feature clouds every night. Not just clouds but dribbles of snow and rain, too! Doesn't the sky know I have things to image?

Next Time, adding a finder to an SBIG ST-8300M.