finally getting some success out of my setup Blackdiamond ed80 and Nikon d3200 DSLR an NEQ6PRO mount. i also have a shorttube 80 ontop with orion autoguider.
Now that im happy with polar alignment and how the scope actually works my next question is the processing of the photos. attached is a jpeg only to give you an idea. im unfortunately in light polluted area and long exposures maybe out, im not sure. when i do short 30 sec exposures my camera doesnt pull much detail but long exposures seem overexposed like the one attached.
I guess my question is are long exposures better and can be fixed in processing or are shorter exposures better because they keep the dark background but little nebula detail. im keen for any advice
nice one, sounds like you are slowly getting it all together.
it is a bit of a balancing act trying to find the right balance for exposure time vs sky glow. I can really only go to about 70 seconds, maybe slightly longer depending on direction.
you need to experiment to see what works for you. of course if you are taking photos when the moon is out it complicates it again (best to avoid). one way of extending your exposure time is by purchasing a light pollution filter.
also are you stacking your photos and using any editing software?
last night was the first night ive really played with the next step so to speak. i took about 100 x 30 second photos of orion and 100 x 30 second dark photos. the background was nice and dark but the nebula looks fairly bland. i only had a quick attempt at deepsky stacker but it didnt come out so well the picture looked worse. ill have another crack at it tonite after work. the good news is it tried to stack about 80 odd pictures of the whole lot.
ive downloaded the trial of pixinsight. i havent had a chance yet to do any research on how to use it properly yet
Usually, the longer your exposure, the better your SNR (Signal to noise ratio). That said there is a point of diminishing return under very light polluted skies. The challenge is to extract your faint data from the background sky glow. Don't worry too much about what you see in your raw as far as light pollution goes. You can always stretch and level your histogram to bring back a darker background. See attached. The more subs (data) the easier it will be to process.
last night was the first night ive really played with the next step so to speak. i took about 100 x 30 second photos of orion and 100 x 30 second dark photos. the background was nice and dark but the nebula looks fairly bland. i only had a quick attempt at deepsky stacker but it didnt come out so well the picture looked worse. ill have another crack at it tonite after work. the good news is it tried to stack about 80 odd pictures of the whole lot
It is pretty normal for DSS to make the pic look more white (I'm guessing that is what you mean by worse). You will need a photo editing program to control the "levels and curves" which can bring the background back to black etc.
I'm not familiar with DSLRs but I would assume that the flats will need to have the bias subtracted from them prior to divide them into the light subs. Do a bit of reading on how it all comes together but bias are the easiest calibration frames to generate, so why not shoot some.
ok cool so 1 last question with the photo i posted above are photos like that worth taking more of and working with or stick with the lower exposure ones to play with.
ok cool so 1 last question with the photo i posted above are photos like that worth taking more of and working with or stick with the lower exposure ones to play with.
hard to tell, the longest you can go before you can't process out the skyglow. that will take some practice at your end (but you can always post what you have up here to double check).
so you'll need to experiment a bit. you've chosen M42 and it is actually a difficult target because the core is so bright and the outer reaches faint (high dynamic range). a lot of people take varying exposures and blend them together - but that's something you can come back to. there are plenty of tutorials on youtube.
I my self use Pixinsight for processing, To say It's not very easy to use would be an understatement but the result you get with it are outstanding. I'm just starting to process but am very happy with the results.
Any picture, regardless of exposure time, will always benefit from calibration. You will get rid of hot pixels, some noise, vignetting or uneven illumination, dust motes on optics, improve your contrast and dynamic range, improve your colors, etc, etc... Get into the habit of calibrating your frames.
Hey, thanks for the link Russell. I've been stuck up against a wall trying to improve my pix and followed the instructions to finally get something decent out of one of my sessions. Now I've just got to go back and reprocess a couple of dozen other sessions ...
had a little play with processing lots to learn and im not sure what the coloured squiggles are or where they came from. this is 30 frames of 30 seconds at iso 100 so im thinking way more exposure and more time or iso
had a little play with processing lots to learn and im not sure what the coloured squiggles are or where they came from. this is 30 frames of 30 seconds at iso 100 so im thinking way more exposure and more time or iso
hi ben,
you're on your way, did you apply the darks you had taken in DSS? i can't really see as i'm looking on my tv, the bits just right of centre?
I think next time you capture data definitely work higher than iso 100, i don't know many people who go below iso 400 with perhaps the average being iso 800 and even up to 1600 for the newer cameras - which i think your nikon would be considered (i used to use iso 3200 when i did exposures from my goto dob they were about 20 seconds). Also I don't know if you said or not but make sure you capture the images in the nikon RAW file format.
Hey, thanks for the link Russell. I've been stuck up against a wall trying to improve my pix and followed the instructions to finally get something decent out of one of my sessions. Now I've just got to go back and reprocess a couple of dozen other sessions ...
Cheers
no worries Brent look forward to seeing the results! sounds like you've got a few repros to do!! I was a bit surpised i couldn't see a tutorial in the ISS Projects and Articles sections - unless i missed it, it was mostly more specialised eg unsharp mask etc etc.
Quote:
Originally Posted by chuckywiz
thanks Rusty yeh ill up the iso now i have an idea how much i can bring the photo back.. im imaging in raw mode..
for some reason DSS didnt like the darks i had so im making some more up now. i guess this is a good learning curve for my next outing tomorow
appreaciate all the advice thanks again
Ben
no worries ben, good luck tomorrow. I (like Marc) encourage you to attempt some flats especially if you set up just after sunset (search twilight flats). On the canon i just switch it to Aperture Priority and snap away i'm not sure what the equivalent setting is on the nikon i'm sorry (a quick search mentioned it may be "A" worth a look).
Spent yesterday at work ( some free time ) playing with old images and a couple of hours last night on more. Didn't realise there was so much good info and detail in many of my early pics. Also got a better understanding of the processes involved and once I had my head around the two limit points I could skip the first levels operation and just pick my points at the curves toolbox and go on from there.
It is only specific to Photoshop though so for those without it they can download it legally free from www.snapfiles.com in the Free, graphics section. This is the free PS2 version Adobe released last year for public use and includes the license string. It works perfectly with your tutorial and for anyone wth any graphics skills is not too hard to understand.
I'll post up a few re-processed images later once I'm happy with them.
I've already recommended your link to another new member with reference to yourself. Once again thanks for the very valuable info and keep up the good work.
It is only specific to Photoshop though so for those without it they can download it legally free from [url removed] in the Free, graphics section. This is the free PS2 version Adobe released last year for public use and includes the license string. It works perfectly with your tutorial and for anyone wth any graphics skills is not too hard to understand.
Actually that is not correct.
Adobe never released Photoshop CS2 for free.
If you download that version then you are using illegal software.
