Hello everyone

[marty1776]

Hello, I am very new to astrophotograohy and wanted to ask a couple question I haven't been able to find the answers to.
I am recording files in a raw format on my dslr. They run in the 25mb range. Is it normal for a 16bit tif to be a lot larger? It was tough to use in star tools due to size after stacking. I started using dng files and they worked much better. Is one better than the other?
Is it normal for a stacked fit to be a couple hundred mb?
I have a couple piggyback wide angle Milky Way photos, I can't get much improvement from star tools. I've watched several videos on you tube but wondered if there's a basic technique to use for those.

Thank you for any help you can give. I'm new to photography but not really to astronomy, this astrophotograohy is kinda intimidating.

Thank you

[Amaranthus]

Hi Marty, For file size, it depends on the megapixel count. The stacked file size should not be much bigger than any individual RAW, unless you've used Drizzle-based stacking. If the file is too large, it may be oversampled, in which case you can use Binning to reduce the size (and noise, if done within ST). Yes, it is a steep learning curve -- just take it slowly and it'll make the climb easier. Show us what you've achieved so far!

[Cheman]

Welcome Marty.

I use a OSC 8megapixel ccd camera (QHY8) My .fit files out of the camera are 11 mb. After stacking in DSS the resulting ..fit file size is about 70mb. So with your dslr, those file sizes seem reasonable. Binning in ST is your friend!!! If you want to, put your stacked file in dropbox or any file share utility, and post the link, someone here can give it a go, and post results and workflow. You can then see if we have improved on your image, and how your workflow might be improved.
This is a great program, and fun to use, but like anyother tool, you gotta learn how to use it!!. Lots of help available here, and great support from Ivo.
Che

[marty1776]

Cool, that's a good idea. I've never used dropbox like that. Here are my two milky way photos I took. I was in a pretty dark spot, I honestly couldn't see to focus and they were 34-40 sec exposures. I'm lucky they are kind of focused, I learned better techniques now, also, there's a little trailing around the edges. I was just getting to know my camera at the time. I didn't know anything about all the other frames DSS asks for to stack so it's just these two shots. Any help would be greatly appreciated, I'd like to elucidate the milky way as much as possible. I've only been able to get it very dark or very light. Thanks for all your help and nice to meet you guys.


https://dl.dropboxusercontent.com/u/63060426/mw1.dng

https://dl.dropboxusercontent.com/u/63060426/mw2.dng

[Cheman]

Marty
I couldnt download for some reason. Dunno why!?
Che

[Alvinillo]

Marty
I couldnt download for some reason. Dunno why!?
Che

Right button on the dropbox links and press 'save link as' or something like that, I translated to english my OS message so it may be slightly different.

regards

[marty1776]

https://dl.dropboxusercontent.com/u/63060426/MW1.NEF
https://dl.dropboxusercontent.com/u/63060426/MW2.NEF
https://dl.dropboxusercontent.com/u/63060426/mw1.TIF
https://dl.dropboxusercontent.com/u/63060426/mw2.TIF

here are the original raw nef files and converted tifs if that helps, thanks again

[Alvinillo]

Hello, I am very new to astrophotograohy and wanted to ask a couple question I haven't been able to find the answers to.
I am recording files in a raw format on my dslr. They run in the 25mb range. Is it normal for a 16bit tif to be a lot larger? It was tough to use in star tools due to size after stacking. I started using dng files and they worked much better. Is one better than the other?
Is it normal for a stacked fit to be a couple hundred mb?
I have a couple piggyback wide angle Milky Way photos, I can't get much improvement from star tools. I've watched several videos on you tube but wondered if there's a basic technique to use for those.

Thank you for any help you can give. I'm new to photography but not really to astronomy, this astrophotograohy is kinda intimidating.

Thank you

DNG file format is an Adobe specification wich try to become an standard. AFAIK, no manufacturer give a damn about it, Canon continues with their CR2 and Nikon with its NEFs. I see no benefits in translating files to DNG.

Yes, stacked files tend to be large files, nothing wrong with it

I've tried to process your pictures,I can't get any significant signal and your stars suffer heavy trailing. You should try to fix your guiding or to shoot more shorter exposures. Stacking two images in not enough, don't be afraid to stack 100 files.

AP is not an easy task but a rewarding one, keep trying.

Regards

[marty1776]

Okay, thanks. Yeah, no tracking or anything, just put the camera on top of my car and let her rip. I will try again.

[marty1776]

Here's another question, I was shooting the ring nebula one night and trying different ISO and shutter speeds(aperture the same as I didn't know how to use it yet). I was just trying to see what looked the best once I downloaded them. If you are shooting something, do you always use the same settings? Or do you try a few, find the one you like for that night and shoot a lot at those settings?
thanks