dark current noise

RedOctobyr wrote:

First off, thank you to everyone who has contributed. This is a really interesting thread, I've learned a bunch, though I need to go back and re-read some of it

I'm not an astrophotography person, but I've enjoyed just taking some simple pictures of the sky at night, and have tried some stacking with my last camera. It couldn't do exposures >60 sec, and dark-frame-subtraction couldn't be disabled, so making star trails was very clumsy.

My E-M5ii has been much more flexible so far, I've had fun with using Live Composite, and I want to try time-lapse at night.

I understand some Pentax (I think) bodies can use the IS to actually move the sensor (or lens?), acting like a simple and limited tracking mount, to reduce making trails during a single exposure. I think that's pretty cool

If Olympus could use their IBIS to manage that, it could be really nice. It would presumably require observing the sensor's output during the exposure, to look for points of light that are moving, rather than using the gyros.

Indeed this is the "Astrotracer o-GPS" and it's supposed to be good for exposures up to 20 minutes. I was considering getting that and the Pentax K-50 before I found out that body is very prone to dust even though it is "weatherproof." It's dust preventing mechanism isn't as good as Olympus's (plus the body weighs a pound and a half.) I would love for Olympus to develop an accessory like this, you would only need a firmware update and to attach this accessory on the hot shoe to do it!

alexisgreat wrote:

Astrotripper wrote:

alexisgreat wrote:

When will major camera manufacturers wake up and offer at least optional TEC cooling for all non-point and shoot cameras? It is simply done and will cause a major reduction in noise. Maybe we can make it ourselves and provide cooling for our cameras to reduce noise even further (especially at higher temps- I am specifically thinking of imaging in the summer when it is in the 70s here all night.)

This makes me curious. I have never looked into this for cameras, and your statement implies this has been done, and is manageable.

But TECs, like Peltier coolers, are often flat plates. They work by drawing electricity to make one of their sides cooler, while making their other side warmer, and overall generating more heat. They're not very efficient, and you need a way to effectively dissipate the heat from the warmer side, otherwise they stop being effective.

So this would increase overall power draw, and would presumably require an effective heatsink on the warm side. I imagine you couldn't use a fan to help remove the heat, due to vibration.

Is this actually as simple as was implied? I don't know, maybe it is, but it doesn't seem to me that it would be trivial. Overall, you'll make the camera warmer, you need to fit more items into the body, and you need a way to effectively get rid of the extra heat that you're adding.

I'm not really sure how easy it is to do but on Cloudy Nights and Astromart I've seen '"modded" DSLR on sale from time to time that the previous owner made TEC cooling for. I never actually did it myself but when I corresponded with the people who made it they said it was relatively easy. One problem they did mention though is that you have to be careful about dew- when you cool a camera down it becomes more prone to dew- so they did what is known as regulated cooling.