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Jaypat75
03-02-2019, 02:25 PM
After an extended time away from the gear, the clear skies in my neck of the woods inspired me to get out the iOptron Skytracker and have a play. I was able to achieve approximately 90 sec subs with relatively decent polar alignment using a Canon 7D and 50mm f/1.8 Mark 1. Obviously the core of Orion is blown out however I was pleasantly surprised to see the Flame Nebula and if you squint your eyes and tilt your head the right way a very vague (but tiny) Horsehead is there too.

Settings were Approx 90 sec subs, f/4.5 varied the ISO between 1600-3200. 15 lights, 5 darks, 5 bias no flats. Edited in LR and cropped.


I have ordered an intervalometer to better control my sub times. Next experiment will be with the 15-85mm at varying focal lengths.


Cheers


Jason

RyanJones
04-02-2019, 09:19 AM
Hi Jason,

Nice capture there. Can I ask though ? If you're using a 50mm f/1.8, why did you run it at f/4.5 ? If you had it at f/1.8 then you could have dropped the ISO right down and reduced noise and amp glow. Unless there's something I'm missing. I've only ever done half a dozen or so shots using camera and lens so there might be a reason I don't know of.

sil
04-02-2019, 12:12 PM
he stopped it down to get a sharper image with rounder stars. using any lens at its "fastest" is never ever the sharpest aperture to use and the amount of difference it makes not stopping down for astrophotography is a dumb idea. no matter how expensive your lens.

RyanJones
04-02-2019, 12:21 PM
Thanks for the explanation Sil. So I guess like everything, it's a balancing act between stopping down the f stop to gain sharpness but that gets negated if you have to run too high ISO and you generate too much noise. In turn you could then get a better PA and go for longer subs ? AP is a never ending mine field isn't it.... ?

xelasnave
05-02-2019, 11:51 AM
Hi Jason
Great image and you wint believe how good things become with the intervalometer...I already love mine...
Alex