Please help me!!!

[Astronut1982]

Hey everybody,

I've got a really frustrating problem I'm hoping someone can help me with.

I was out last night trying some AP with my new UHC filter & used M42 as my target as it is nice & bright. I had a look at the pics on the LCD screen as I was taking them & I was fairly happy, they had some nice colour & the trapezium was visible.

When I got in & tried to process the pics I put them onto my computer & looked at them using Picassa to see what they were like. At first they came out just as they looked on the LCD screen but after a second it brightened up, washing out the heart of the nebula. Its happened before & I'm getting really cheesed off as I'm unable to use them to stack with. I've enclosed a pic for you guys to have a look at.

My camera is a Nikon D5100 & I set the camera on a 30s exposure with an ISO of 1600. As I said before they look good on the LCD screen so why are they coming out much brighter on my PC? Is there a way for me to correct this in post processing using photoshop CS5 pro or are these pics wasted?

Thanks in advance as always for your help,

Jeff

[Freff]

Hi Jeff, I would not rely on the LCD display to give an accurate result. I find the histogram to be much more reliable.

I'm sure that the detail is lost in the blown part of the image and can't successfully be retrieved in Photoshop.

[Tim]

I dont know the Nikon format, but are you able to take pictures in a RAW mode?

If so, use and stack them, as anything output to jpeg for instance will have less info in it.

When you are taking the sequences, try to keep the histogram spikes on the left side of centre.

[malc-c]

Not brill, but simply pulling the curves helped a little. But a single 1600 30s exposure at that ISO appears to be a bit noisy when stretched

[Tinker1947]

Nikon's do RAW files, DSS accepts them.

[Astronut1982]

Hi guys,

Thanks for the help. I played about with the histogram & I've got it sorted. You guys are absolute legends!

I'll be doing that everytime from now on.

Again, thanks so very much,

Jeff

[Astronut1982]

This is how it turned out after I adjusted the histogram on the D5100. I don't think it looks too bad now.

The only thing is, once saved it is converted into a JPEG file which is no good for DSS. Is there any way to save them in as RAW files so that I can stack them using DSS?

Jeff

[malc-c]

I would think you need to change a setting on the camera to save the file in RAW format on the storage medium (CF or HDSD). As far as I know it's not possible to convert JPEGs etc back into RAW format.

[Freff]

That image is a lot better Jeff. Remember the LCD will display the jpeg image only dispite being in RAW mode. It's how the camera THINKS it should look.

The histogram is the graphical representation of the distribution of data of the RAW image.

[todd8137]

hi there it seems no one reads up on any thing any more ,just buy the kit and struggle from there ,theres a few books on the subject knowledge is power

[RikM]

Doesn't Picasa auto processes images when you open them? I remember my wife using it to organise some holiday snaps once and it messed with the colour and contrast. A bit like hitting the 'auto levels' and 'auto contrast' in Photoshop. Not good for daytime photography and hopeless for AP.

As said above, use the histogram, save as a RAW file. Ditch Picasa and load the RAW's directly into DSS. Look at them in preview only in the DSS screen and uncheck any you don't want to include then tell it to stack 100% of the checked ones.

[Astronut1982]

Hi guys,

Thanks for your advice, I've managed to solve that problem I'm having.

Jeff

[todd8137]

hi there it seems no one reads up on any thing any more ,just buy the kit and struggle from there ,theres a few books on the subject knowledge is power

Hi Todd,

Thanks for the [not so] kind reply!

I do have many books which I've read in order to gain knowledge. I also have ordered a copy of 'making every photon count' which I am currently waiting to receive.

I just had a problem which I couldn't find a solution to in the books I currently have or on the internet. It was really bugging me & I was becoming so frustrated that I couldn't wait until it arrived so I thought I'd come on here & ask for some advice in the meantime. Fortunately others are very helpful & are willing to share a little of their vast experience & knowledge.

To be honest thats what I thought this forum was for, an exchange of ideas, advice & a chance to discuss our hobby with like-minded people.

If, in future you feel my posts are beneath you or are boring you, then please feel free to refrain from replying to them, or just ignore them altogether.

Jeff

the comment was a general one reading books on subjects gives you knowledge on any given subject, every photon counts is a great book so knowledge is power i would not buy a camera before do in some research as when i did get the cam ,i would have a good idea i`m sorry you feel offended as it says in your pm to me, i shall refrain from coms on your posts i the future,i have about 20 people here on sgl who come to visit me regular and i go to there houses to help them with there kit and get them going i do not be-leave you post are boring or beneath me you seem to let your frustration and if you read my comment properly you would see that.and to be honest lots of people rush out and get kit and then strugle thats what sgl is for and the forumsare for so my comment is valid and will stand by it am sorry you felt offended so in the future i will not help any one else or give advice on the subjects i no about

thanks .................................................

[Astronut1982]

Todd,

My apologies for misreading your post then. The 1st part of your comment came off a little condesending which is why I came to the conclusion I did.

You do seem to making several incorrect assumptions about me though. When I purchased the equipment I do have, I did do some research into what it would be good for, how difficult it would be to use & so forth. As for the camera I was given that as a gift so was unable to do some previous research on it. I was only doing planetary photography with a webcam & was looking into a DSLR or deep space camera when someone bought me this as they knew I was looking into purchasing one. I am aware how to use a DSLR, use most of the manual settings and so forth but mucking about with the levels is a little beyond me at the moment until I get the books & read up on what I need to know which is why I posted here.

I now appreciate that you were giving me advice but as said the 1st part of your comment did seem a little sharp & not quite so friendly.

So once again my apologies for misreading it.

Jeff

[malc-c]

C'mon guys, shake hands and make up !

I think the RTFM syndrome is common place, and always has been. Regardless of what device or kit people buy they tend to jump in and try and fathom it out and then read the manual (assuming they still have it) when they get stuck. Often it's easier to learn by asking questions or being shown by someone who already knows what to do, which is why this forum is such an ideal place to visit, especially as some topics aren't covered in any manual or book !

[todd8137]

may be i should have put it in a different way not to worry i just hope i did not cause you any upset or any thing else and you right sgl is just about the best place for help

[GJBC]

Hi Jeff

glad you have got the issue sorted and i like the images you posted it reminds me of when i tried AP for the ifirst time with a dslr it took me a while to get things correct and the whole process tied down.

to get me ther (and you might have them already) i purchased two CD online i am afraid books dont do it for me it has to be quick and to the point and the video tutorials on teh disks are my choice of a learning tool i will read up when needed but i learn best when someone shows me and then i have a go.

i purchased these two titles and they helped me no end link to pages

A Guide to Astrophotography with Digital SLR Cameras

Astronomical Image Processing Tutorials by Donald P. Waid

they do cost but for me it was money wel spent.

the images you have published are they stacked or single images?

[Astronut1982]

Todd,

Thats no problem, no offence taken. I'm just glad we understand where we're both coming from now. I really don't want to fall out with anyone here as I've met some great guys who have given me some very good advice & I hope that once I gain enough knowledge that I can do the same one day.

GJBC

Thanks for the recommendations, I will look into purchasing those cds. Hopefully they'll help me get the best of astrophotography.

The pics I have posted are just single 30s exposures with ISO of 1600. I'm going to try & stack them with DSS & see how they turn out.

Jeff