M51 First Guided Image

[cuivenion]

My latest image of M51. Taken with an Altair GPCAM and a Chinon 2.8 135mm lens stopped down to F4.6 on an AstroEQ Vixen GP. Guided by a PS3 Eye Finderguider. Finally sorted out my guiding system so I can do exposures over 60 seconds. Taken on 24/03/2017. Imaged with Sharpcap.

18 x 5 minute exposures.

100 Flats

20 Darks

500 Bias

I had a couple of versions I liked, I went with the least noisy version:

 

[Galen Gilmore]

thats a great image!  

im not an imager, but arent you supposed to use less darks than light frames? Considering your dark frames use the same exposure and ISO as your lights.

[cuivenion]

2 minutes ago, Galen Gilmore said:

thats a great image!  

im not an imager, but arent you supposed to use less darks than light frames? Considering your dark frames use the same exposure and ISO as your lights.

Thanks Galen. As far as I know the more darks the better. The principle for stacking is the same for lights and darks. The more you stack, the higher the signal to noise ratio. At least that's that I've read.

it's a shame I couldn't get more frames as I was out most of the night, but due to inexperience I had quite a few problems before it all came together.

[Jannis]

Thats a great capture! :-) is it really taken at only 135mm? Its stunning resolution for that low focal lenght!

As for darks, you are correct - the more the better. As with any calibration frames, If you can keep sensor at same temp, and conditions otherwise as well, go ahead and take 20, 40, or even 500. Its really just going to calibrate the light data better. :-) 

[cuivenion]

 

3 hours ago, Jannis said:

Thats a great capture! :-) is it really taken at only 135mm? Its stunning resolution for that low focal lenght!

As for darks, you are correct - the more the better. As with any calibration frames, If you can keep sensor at same temp, and conditions otherwise as well, go ahead and take 20, 40, or even 500. Its really just going to calibrate the light data better. :-) 

Thanks Janis. The GPCAM v1 has fairly small pixels, 3.75 microns. That increases the magnification. It's a bit of a lottery on how well the darks work with an uncooled cam, but I have to use them to reduce amp glow. Oh for a cam with set point cooling!?