Finally after over a month since I started to collect AP gear, I finally have a picture to post. I'm just testing still at the moment to get the workflow in hand. This is a single frame out of my Canon 450D on a Skywatcher f5 6" Newtonian. It's a 3 minute sub that was simple converted to PNG and downsized so I can post. No processing has been done.
I'm still waiting to install my focuser, so this was a rough hand focus using liveview on the camera back.
So, with those caveats, how does it look? Any suggestions on what I need to do to improve my captures? I'm currently running 20 3-minutes subs. I don't have anything to capture flats just yet, and I'm not sure if I need darks & bias as I've seen conflicting reports on whether they are needed these days or not?
Also attached is my guide scope graph - how does it look?
Russell
Looks very promising for a 1 x 3 minute sub
Imaging with a DSLR , particularly during the summer you will definitely need darks to remove hot pixels and dithered subs to reduce fixed pattern noise
DSLR’s take a hammering in the summer where your sensors electronics can get up to 35 to 40 deg C during long exposures
Looks like your well on your way now with tight stars at 3 minutes , also your total RMS of 0.85 is excellent
Well done !!
Thanks guys. I am running a dark series just before packing up for the night. Tomorrow will be back to DSS & photoshop to see how the next stage of the process goes.
Would you believe my camera battery died on the last Dark frame last night? Could be a problem as I'd only used it for 2 nights, a couple hours each night. it is the original battery though, so capacity may be down. I have a generic spare from eBay, so we'll see how it goes.
Here's my first attempt at a processed image. It's kind of tricky keeping the noise out but the detail in. I'm using the trial of StarTools to see if I can work with it. Seems nice so far, but lots to figure out. The attached picture is just a 50% screen grab from where I got to when I seem to have gotten all I can from the image with my limited experience. Not sure if I went too far with the noise reduction, not that you'll be able to tell in this scrunched down forum version of the file anyway.
Fantastic first effort Russell ! 2 tips I’ll offer you with regards to DSLR capture. Firstly Darks will make a huge difference to how much you can stretch the image in post processing. As to how many that’s up for debate. I generally work around 10-15. I do however tend to take a few while I’m setting up my guider at the start of a session as well as at the end to capture darks at the varied temperatures throughout the night. Flats also make a big difference when you’re stretching the image as they will give you an even luminance across the image. The second tip is to stack more images, even if you have to spread the capture over a couple of sessions. This will again give you the ability to extract more data from the noise.
In any case, what you have done for a first effort is excellent and you should be very proud of what you’ve achieved! Well done.
Great result Russell
Well done !
Startools has so much to offer , I can give some tips later on whenever you get more proficient
I usually take 15 darks for up to 40 subs and 20 darks for anything above 40 subs
Darks work better if you take them after your subs as your sensor temperature will be closer to your sub temperature , the closer the better
I wanted to do 40 subs, but time was against me. Wasn't sure on the exposure length either. I originally did 4 1600 ISO subs and a quick stage to see if it was pulling any details, and it seemed OK. I was going to drop the ISO to 400, but that would have doubled the capture time, so I stuck with 800 as a compromise.
Oddly while doing the first 4 subs, in the second one, the stars showed a short straight trail with about 5 brighter spots along it, as if the telescope moved sideways and stopped briefly each time. The only thing I an think of is if my dogs went out and were bumping the mount or something. Not sure what else would explain it except and earthquake....
Hi Russell
You have done very well.
When using a DSLR I have one battery in the camera, a charged one in my pocket, and one charging. When you start to do a large number of subs you may be surprised how fast they run down.
I look forward to seeing more ...I think you may leave us all behind with a start like that.
Alex
Russell
You will find your ISO sweet spot at ISO 800 for the 450D but experiment with it all the same
My 600D is left on ISO 800 for all my images in all sky conditions and targets
Remember to view your histogram when evaluating your exposure time and ISO after a test sub
Usually subs sitting at 1/3 across is a good bench mark but not any further
Cheers
to the forum Russell. Your 3 min sub is looking good & guiding right off the bat is great way to start, well done & keep posting.
