A terrible Cat's paw and Lobster

[cometcatcher (Kevin)]

Do you guys ever get those objects that are a real pain to get anything from? I don't know why I'm even posting this. Perhaps because I've been slaving at the computer for hours and hours and need to show something for my suffering. That, and this is the first time I've shooted both these objects in one frame. Cats Paw - NGC6334 and Lobster NGC6357.

While I'm complaining, this old Nikon D70s that's been full spectrum modified is an absolute pain to work with. It's incredibly noise, gets quite warm to the touch, only pics up Ha and not much else. Where's the frustrated emoticon? Some of it is my fault for trying to get a full colour image of faint objects in moonlight. Silly me.

The ingredients for this mess was an ED80, Orion 0.8X focal reducer, focal ratio F4.4, 31 x 1 minute subs with a Baader Semi-apo filter, 14 x 2 minute subs with an Astronomik CLS and 9 x 2 minute subs with a no name brand Ha filter for a grant total of 77 minutes.

What I should have done, dithered more, guided, used a lower ISO, used no filters at all and took 100 hours of data without the Moon.

There, I feel better now. Thanks for listening to me complain.

[rcheshire (Rowland)]

I'm not absolutely certain Kevin, but I think 2 minutes is too short with a CLS filter. 4 - 5 would increase the background and object flux and eradicate some of that noise. Total time is what matters, but 2 minute CLS subs will be noisy.

ISO 800 or 400?

[SimmoW (SIMON)]

Ha, we feel your pain! What temp was it outside when you took the images? I've found SLR sensors to be real noisy once the temp gets above 10c. I suspect you are getting the most out of the equipment you have. Nice composition actually.

Did you try to reduce the noise with any software? That can help heaps.

[cometcatcher (Kevin)]

Thanks Rowland and Simon. Ambient temp was 23C, rather high for winter, must be global warming. The temps never go much lower than 10C here anyway. The D70s is getting a bit long in the tooth also. It's a 2005 model I think so 9 years old now. It doesn't like ISO1600 (what the above were taken at) for longer than a minute. The frame becomes a sea of noise. ISO 200 and 400 are better with it but require tracking for the longer subs and a cloud free moonless night. What are those again?

I haven't seen noise reduction software that I like yet. They usually cost detail somewhere along the line.

Edit, just looking at the individual subs, they are quite well exposed, I could have probably taken the ISO back to 400 or 800. Nasty amp glow I have to contend with in the top left corner.