hey there all, just a question on this SBIG cam, I don't know what im doing last effort produced a majorly over exposed pictuer of jupiter...? some basic settings and advice would be excellent
I think you will have to not only use the camera's shortest exposure setting (0.04s) but you might also need to barlow up Jupiter to reduce it's surface brightness.
Brenden, I had myself considered this path to use such a Sbig camera for dual purpose DSO and Planet imaging. The Inspiration was this chap Ed Grafton who really did some great things with the Sbig cameras. http://www.egrafton.com Look at this website and check out Ed's guide. There use to be a SBig application called Planet Master, which is now built into the Sbig CCDOps application.
Whiel Ed did take some wonderfull shots there are some limiatations of this technolgy when compared to modern high frame rate UBS 2.0 and Firewire camera's. Even at shorter exposures you will still not capture as many frames as with a Webcam. This is due to the time to download the frame to your PC. Not sure on the St402ME download speeds on short exposure frames. This is an issue with planets like Jupiter which rotates quickly. However with Planets like Saturn and others with a slower rotation this is not such a big issue as you can take the frames over a longer period of time. Hence you will not Ed's Saturn Images are not to disimilar to the best that is being taken these days.
all the gear that i have use of aka lx200 sbig ect ect is all curtin univeritys, they have gone out and splashed some money without too much research!
so the LX is what we have. Im lead to belive that a Wedge is definately needed for longer exposures. (i can already see this as the stars arn't perfectly round they have tails).
My problem that i found was that no matter how hard I tried all stars where white (over exposed). I used the CCD Ops program with planetary master to focus in on things with peak values and the image looked for all intents and reasons fine.
Slip into the grab part of CCD ops and selected a colour grab with say for the Jewel box at about 3 seconds with a 1.3 multiplyer on green and a 1.6 on blue and the resultant combined image was .... you guessed it black back ground (with a little bit of noise) and white stars. I also observed that subtracting a dark frame killed all little stars or dim stars. We had also tried the Triffid Neb but could only get a hint of nebulosity, the exp times where 18 seconds with the same multipliers as last time. am i in the ball park or did i end up in swahili land?
Some help? ideas on settings or what to do? any takers on a monday night observing session with a little bit of learning attached?
"Look at your exposures, it should be in the ms, not seconds.
Try starting with 10ms
Theo. "
The cam was exposing at 40 milli seconds the lowest it can go and still bright blob!
From what i can read the scope is a RC specially built for Astrophotography this is why i cant understand why it wont proform.
Its not the telescope or camera, its your processing skills (Sorry).
You have a very good camera and an excellent scope.
There are some help links here http://web.aanet.com.au/gama/help.html which is on my help web page. It should take you up a notch in skills i hope.
As for the Jupiter over exposure, as others suggested, you need to stop down your scope (Block more light) to get the image better.
Its not the telescope or camera, its your processing skills (Sorry).
Theo.
hehehe i could have told you that, i just would have expected with todays technology that to take a rough colour picture should have been a damm site easier... The skill should come in to get a excellent colour picture!
I guess the problem i face at the moment is that the instruction booklet will take me a week to read though because its huge and there are so many options to tick click and fiddle with that its extremely confusing for a noob like me.
If there was a guide that said press this button enter this value and or just had a manual to take a picture of a known cluster aka the jewel box so that the reader could replicate a decent kind of photo and then once its known you can change the settings for different targets and fiddle!
Last edited by bmitchell82; 20-08-2008 at 10:30 AM.
Reason: putting a photo of the jewel box
You should be able to get the Jewel Box without it "burning out" the stars. It's been a long time since I tried such an object with my LX200 & SBIG but I'm pretty sure with a minimum exposure time I wouldn't have a problem.
You need to come to grips with the capture and processing software, not a quick task unfortunately. I'm not familiar with CCDOps, I quickly gave it up in favour of CCDSoft which also came with my (and all I think) SBIG. For LRGB imaging I usually end up using Photoshop as much as CCDSoft.
You need to capture exposures where the stars aren't burnt out, in CCDSoft this would be ca case of looking at the maximum ADU of the image, or moving the mouse over the stars and reading the brightness (ADU) in the status bar of the app. Checking it's not at the maximum of the camera. Or playing with the histogram a little to check there's range left.
You then need to combine the LRGB exposures and fiddle with the settings in doing so. CCDSoft has a colour combine function which would give you basic results reasonably easily after some fiddling with the sliders for the exposure of each component (LRGB).
Once that's all done you could save as TIF and load into Photoshop to make it look nicer again.
As other have said, Jupiter isn't a good target for the equipment you've got. I'd suggest a galaxy or nebula with even brightness across the board, where details shows well in 10 sec exposures. Mag 8-10 kind of objects. I haven't been doing any astronomy lately to remember what's up at the moment to specifically recommend one, sounds like you're capable of finding one anyhow (you got to the Jewel box).
I don't think the equipment you have is necessarily bad or a bad choice, you just have to learn to work with it and what it suits, not battle against it with the wrong kind of target - something which takes time & experience.
hehehe i could have told you that, i just would have expected with todays technology that to take a rough colour picture should have been a damm site easier... The skill should come in to get a excellent colour picture!
I guess the problem i face at the moment is that the instruction booklet will take me a week to read though because its huge and there are so many options to tick click and fiddle with that its extremely confusing for a noob like me.
If there was a guide that said press this button enter this value and or just had a manual to take a picture of a known cluster aka the jewel box so that the reader could replicate a decent kind of photo and then once its known you can change the settings for different targets and fiddle!
The data is there it is just not demonstrated well by the CCDOPs program. With such short exposures you shouldn't be completely saturating the CCD. It has to do with the auto display of the data. In the top right hand corner you should have a little box with an upper and lower value for the image. Try Making the upper one much higher -like 10000 and see what it does to your image after you take it.
CCDOPs isn't much chop at displaying the images.
Try saving the file you take as a fits file and opening it in another programme. I use "Iris" as it is free but there are others that will also do the job.
finding targets is the easy part, i have a heap of A star atlas's, B The sky6, Stellarium, and Asynx. I just picked the jewel box because i can point it out without even thinking. after the success i had with that i moved to something even duller. aka Triffid Nebular, on 18 second shots i could start seeing the nebulosity, though the stars where just white. when i bumped it down to 10 seconds the nebulosity dissapeared and the stars becaume a little bit duller as would expect but no colour.
As for the ADU theres a program in CDDops called Planet master which allows realtime view of what the ccd is picking up, i use it to focus in because of the peak value. is the peak value the ADU or is ADU the actual brightness of the star on the CCD chip?
I have also played with the Range and black screen in CCD ops that did little to help myproblem.
Last edited by bmitchell82; 21-08-2008 at 04:15 PM.
I guess the problem i face at the moment is that the instruction booklet will take me a week to read though because its huge and there are so many options to tick click and fiddle with that its extremely confusing for a noob like me.
Make the effort. RTFM. It will be worth it.
The ST402 will happily go 5 minutes or so with the Jewel Box before the camera saturates.
Apart from focus and tracking, the data is there. You just need to tease it out. Try gamma scaling or DDP each R, G and B exposure so the stars look, well, like stars, rather than featureless blobs. Then combine the RG&B data.
all the gear that i have use of aka lx200 sbig ect ect is all curtin univeritys, they have gone out and splashed some money without too much research!
so the LX is what we have. Im lead to belive that a Wedge is definately needed for longer exposures. (i can already see this as the stars arn't perfectly round they have tails).
With my 12" LX200 I couldn't get the stars as round as I did with my refractors, even with minimum exposure times. I used Canon 40D with them. I guess that's the way SCT's are.
With my 12" LX200 I couldn't get the stars as round as I did with my refractors, even with minimum exposure times. I used Canon 40D with them. I guess that's the way SCT's are.
How round your stars are probably isn't to do with the fact it's a SCT directly. SCT's often have poor flat fields, so you might get illongation of stars on the edge of FOV, but other than that you should have circular stars if your tracking and focus are good.
It's more likely that you don't have circular stars because SCT's typically have much longer focal lengths than refractors, so any tracking error in your mounts will be much much more obvious on the SCT than refractor.
The ST402 will happily go 5 minutes or so with the Jewel Box before the camera saturates.
Apart from focus and tracking, the data is there. You just need to tease it out. Try gamma scaling or DDP each R, G and B exposure so the stars look, well, like stars, rather than featureless blobs. Then combine the RG&B data.
I know RTFM is a great idea, but remembering im a uni student that has a overload semester in engineering. which isn't a walk in the park. I use my one monday evening every week to A. take a break, B. Get out of the house, and C. get away from the mother inlaw.... not only that i have all this gear here that i have the option to use because i have helped curtin uni a bucketload and I have prepared lectures on telescope optic's (physics is a favorite of mine). So basically they say. yep you can use it pretty much by yourself.!
As for the jewel box, the photo that i added first was taken at 40 milliseconds...???....! i took one at 10 seconds and all i had was big white lines from one side to the other. and the range was all taken up and maxed out. Now weather there is a "gain" and its wicked right up im not sure. but ill figure it out eventually!
I am a beginner and if it was me i would have started with a trusty EQ6 mount and a Skywatcher ED 80 with some nice gear to suite and then get some decent shots, but im working with what i have for now!
finding targets is the easy part, i have a heap of A star atlas's, B The sky6, Stellarium, and Asynx. I just picked the jewel box because i can point it out without even thinking. after the success i had with that i moved to something even duller. aka Triffid Nebular, on 18 second shots i could start seeing the nebulosity, though the stars where just white. when i bumped it down to 10 seconds the nebulosity dissapeared and the stars becaume a little bit duller as would expect but no colour.
and the range was all taken up and maxed out. Now weather there is a "gain" and its wicked right up im not sure. but ill figure it out eventually!
