Hi Guys,
First I would really like to thank Colin, bojan, Mark, Rom and Kevin for your comments on my last Post here (Tarantula NGC2070).
The shots below where taken with my new cold camera mark2. This time I used a canon 600D with a cold finger and I'm very happy with the results. My mark1 camera used a canon 1000D in a box, based on the Gary Honis design (with a few modifications). I might add I have already started mark3 (a better Cold Finger).
One thing I like about this hobby, you are always leaning. Having read the
"Aperture, f-ratios, myths, etc., by Craig Stark" and now finally understanding that stacking doesn't get you any more detail, or make the object brighter, but does improve you signal to noise ratio, I have started to take much longer exposures. With the light pollution here I can do up too 5 minutes exposures with the histogram peaking just above 1/3 at ISO800 (best ISO for this camera). I'm thinking that I could probably push the histogram to about 2/3 on some of the dim object, which would get my subs up to 10 minutes, I'm not sure how well this would work, I will have to test this idea.
The shots below were taken with 150mm Esprit, 5 minute subs, Darks, Flats, etc.
The Horse Head Nebula (IC434), has always been a real challenge for me with Melbourne's light pollution (but I'm getting better at this) coupled with the City of Knox introducing Broad Spectrum LED'S for the street lighting, it is not going to get any better.
Might be time to move back to the C11 and onto Galaxies again.
Some more nice images Peter. You're doing well to get the horse through light pollution.
I could really use a cold finger mod this time of year here in the tropics.
Hi Kevin,
Thanks for you comments. I started to cool my camera down when one particular hot night at the beginning of 2016, my Darks where RED instead of Black. That pushed me to looking at camera cooling, and I have not regretted the move. With my current system I can keep the sensor at about 10 to 12 Degrees when the outside temperature is 30 degrees. With a better cold finger (Camera Mark 3) I should be able to do better.
I find that if I keep my 1100D sensor down to about 12-14C it does well...no significant improvement below that IMO.
Agreed, you run into the dreaded dew\ice problem as well as you approach zero. My best result with the 450D was 5* but my ambient was about 10* below yours. I could get down to -15* easily enough but it was a major issue to manage the icing and there appeared to be very little gain if any in noise reduction.
It also required very little power to the Peltier to maintain 5* btw.
Hi Dunk and Brent,
I have my camera in a hermetically sealed box loaded with silica gel,
even then I have seen a little condensation at times. My next trick is to fill up the box with argon, to see if this helps. I have remove the back off my camera as it is not needed any more, it is totally controlled from Backyard EOS, which means that the argon can permeate into the guts of it. I think you are both dead right, below 12 degrees probably doesn't achieve a lot. My thought is if I can fill the space between the reducer and the camera sensor, as well as the back cavity with argon, then this may help a little. I have some argon on the way, so I have not tried this theory yet. My aim is to keep the sensor at reasonably constant temperature over a 5 to 10 minute exposure. That length of exposure is about the best I can do from Melbourne's light polluted suburb of Boronia.
Thanks Rick, there are some people in this forum that can produced Sky and Telescope front page pictures that blow your mind, unfortunately I'm not in that class. Having said that, I once read in an Astrophotography book "if your are happy with the pictures, that's all that counts" and I'm very happy with them.
Not saying that there is no room for improvement, there is.
