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Showing results for tags 'exposure time'.
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Background info: I have 2 scopes a nexstar 6se (150mm aperture and 1500mm focal length - f10) and a evostar 72ed (72mm aperture, 420mm focal length - f5.8). I haven't had chance to use the evostar yet thanks to the clouds. Question: Does the f5.8 mean I'm going to be able to reduce my exposure time or is it cancelled out by the fact the aperture is so much smaller?
Does Focal Ratio affect brightness or is it all about field of view. Will an f/5 scope show the Andromeda galaxy more brightly in the eyepiece than an f/12 scope, or is it just about fitting Andromeda in there and seeing more of the sky? Also does the Focal Ratio of a scope have any effect on the amount or length of exposures taken in astrophotography? Thanks.
Hi Guys, Long story short: Is it worth doing 4 min exposures with ISO 100 using Canon 1300D (not yet moded..) on DSO. Or it's better to stick with default ISO 800 and 1min? @ISO800 1min is the top exposure I can use from my back garden in London even with a light pollution filter on.... Long Story: I "recently" managed to get all beginner's equipment and started to experiment with long exposures (I had DOB previously). "Recently" - almost 2 months ago, and during that period I managed to play with it 3 times only... London is like the Adams Family house, - constantly under the clouds... I have Canon 1300D and SW 130PDS guided via ZWO224 (not completely guided yet... as still learning ). Initially, I thought I will figure out the best ISO/exposure settings while experimenting... But 1 experiment per month... VERrrrY painful... and it would be the top rate masochism to enjoy experiments with such a frequency... So I have been googling, reading forums and even going through the astrobin/flickr pictures and checking ISO/Exposure parameters, checking all kind of data sheets with sensor data, but managed to find only for Canon 1200D like for example http://sensorgen.info/CanonEOS-1200D.html or http://www.photonstophotos.net/Charts/DXOPDR.htm and nothing for 1300D. If you have any link, you are welcome to share. From all data I have read for my range CANON ... usually, - ISO800 is recommended or even ISO1600!!! - Wow!!! Seriously??? I used ISO1600 with my DOB for 10sec exposures As far as I learned, - All DSLR cameras have the best Dynamic Range with the lowest ISO possible, with 1300D it's ISO100, so I would expect to get the best DSO colours and shadows using ISO 100, However, I was amazed founding out that Canons have the Highest Read Noise at low ISO settings... (I was not able to find any data for 1300D, but I guess data from 1200D sensor is more or less the same). It looks like a sweet spot would be ISO 400 which would be 1.5 - 2min exposures maximum... Please correct me if I am wrong. P.S. Last time I tried ISO800 and 1min exposures, - after stacking with all darks, flats and bias the result was very noisy. I even afraid thinking about the amount of noise with ISO100, but I will try it next night anyway... Curiosity ...