Antares_Paul Posted June 11, 2012 Share Posted June 11, 2012 Hey guys, Quick one - if I only have a small imaging period (clouds etc) is it better for me to run for example 6x2 minute subs, 3x4 minute subs or, accurate tracking allowing, 1 single 12 minute sub for gaining good data? I have so far tended to go for multiple short subs but can see already certain targets require longer than 2 minutes. Perhaps I have answered my own question? Roll on Winter with, hopefully, uninterrupted clear dark skies Regards. Link to comment Share on other sites More sharing options...
Guest Fluke Posted June 11, 2012 Share Posted June 11, 2012 Im interested to know what the guys think about this too. Link to comment Share on other sites More sharing options...
Guest Kheldar Posted June 11, 2012 Share Posted June 11, 2012 1x12 Signal to noise ratio increases with time, longer exposures are better. Given the caveat that your imaging gear might not respond well to that 12 minute sub (noise from the device from thermal or electrics, over saturation of stars.) Whilst I won't dispute you can get good results from minutes worth of data, you really want to aim for hours, over several nights if need be to really get those stunning photos Link to comment Share on other sites More sharing options...
Antares_Paul Posted June 11, 2012 Author Share Posted June 11, 2012 (edited) ... you really want to aim for hours, over several nights if need be to really get those stunning photos Yes Stephen that would indeed be the intention The topic was started due to our awful skies atm and lack of sky time available I'll go with 4 minute unguided subs for the time being and as things improve increase the sub lengths and maybe even start the guiding I've had a few trial runs with PHD and it's all playing. The best thing I did was mark out my 'home' position on the patio so a repeatable set up is possible and, thus, accurate polar alignment readily available. I only need to tweak the alt/az bolts now and then. Many thanks for your reply. Regards. Edited June 11, 2012 by Paul Laws Link to comment Share on other sites More sharing options...
red dwalf Posted June 12, 2012 Share Posted June 12, 2012 4 minutes unguided might be pushing it alittle, i can`t go much more than 1 minute 30 before getting star trails Link to comment Share on other sites More sharing options...
Perkil8r Posted June 12, 2012 Share Posted June 12, 2012 An interesting thread, and a dilema I have been pondering too. Looking forward to some clear skies to give some various sub lengths a go so I can see how far I can push my set up. I've managed to tweak my set up quite a bit recently so it's a lot more accurate than it was, hopefully I can push the exposure times quite a bit further than the 30 secs I was doing before. Link to comment Share on other sites More sharing options...
Guest Kheldar Posted June 12, 2012 Share Posted June 12, 2012 My personal feeling is without stellar kit, you're going to get 2 mins absolute top (perfect PA, no wind or vibrations, no PE) Link to comment Share on other sites More sharing options...
Perkil8r Posted June 12, 2012 Share Posted June 12, 2012 2 mins will be a 300% increase on my current exposure times, so I will be over the moon with that lol Link to comment Share on other sites More sharing options...
Antares_Paul Posted June 12, 2012 Author Share Posted June 12, 2012 Think I will shoot a 5 minute test sub anyway, see the carnage, and work backwards to find my limits. Even if I only get to 150 seconds unguided - it's 150 seconds All good fun ... Thanks again for the replies. Regards. Link to comment Share on other sites More sharing options...
Guest Kheldar Posted June 12, 2012 Share Posted June 12, 2012 Think I will shoot a 5 minute test sub anyway, see the carnage, and work backwards to find my limits. Even if I only get to 150 seconds unguided - it's 150 seconds All good fun ... Thanks again for the replies. Regards. Good plan With unguided make sure you get the basics down, PA and balance will return you the best results if they are good. Link to comment Share on other sites More sharing options...
andyboy1970 Posted June 13, 2012 Share Posted June 13, 2012 Noise increases with exposure length, lots of shorter exposures help keep the noise down. What camera are you using? I find with my 1000d that 3 minute subs are best. Link to comment Share on other sites More sharing options...
Antares_Paul Posted June 13, 2012 Author Share Posted June 13, 2012 Andy - it's a 450D. I allow 10 seconds per minute (eg 20 second delay for a 2 minute sub) for the sensor to cool a little between each shot. Run EOS Utility but will switch to BYE when the auto focuser bracket is sorted. I am using battery power atm but will switch to an AC PSU as the nights draw out. Currently manage 2 hours with the battery. I powered up the cheap Chinese PSU for 6 hours when I first bought it and it was reading 7.78 volts solid over that time span so I'm happy with the regulation. Canon's prices are outrageous. There is no amp glow @ 2 minutes. Regards. Link to comment Share on other sites More sharing options...
andyboy1970 Posted June 13, 2012 Share Posted June 13, 2012 I splashed out £40 for a second genuine Canon battery, but the 1000d goes for about 6 hours on one battery. Link to comment Share on other sites More sharing options...
Antares_Paul Posted June 13, 2012 Author Share Posted June 13, 2012 I'd prefer to run original Canon stuff but they won't meet us half way price-wise I'll probably get 2 new Canon batteries later in the year rather than leaving the life of my camera in the hands of a 9 quid knock off. Regards. Link to comment Share on other sites More sharing options...
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