Hey all. Felt alittle uneasy posting these as there pretty sad compared to the rest that are on show.
Anyway, took these all in one night {no sleep/annoyed girlfriend}. Lots to figure out but im happy as these are my first images apart from the blown out omega cent i posted 2 weeks ago
All 30 sec exp and about 15 stacked {all i could manage cause of evil clouds}
How do i get detail without the stars blowing out?
Anyway.. here goes {be gentle as it was my third go of using the camera
1. Centaurus A
2. Lagoon Neb
3. M31
4 m61
5. M83
6.Ring neb
7.Omaga Cent
8. Dumbell neb
Comments and tips very welcome
Thanks all
A good alround collection Josh. That M57 is a cracker, as is M27 and OC. The small version of M83 looks great but I think your focusing may have let you down a bit with that one. Btw, M31 is M13 in Hercules. If you waited a few more hours, just on dawn you would have gotten M31 but it would have been a big capture as the DSI would have needed to do a mosaic to fit it all in
Try not to feel uneasy, though I think many here, definately myself included, can understand where you are coming from. We all started out as newbies once upon a time. The general idea is, you post, we appreciate, offer positive critiques, you go away with new info and post your next round of improved shots.
The burning out of the stars is called sigma clipping and comes from either too long an exposure (individual exposures), or adjusting your white point too low when processing with curves or levels. Do you use a program that has a histogram to use when processing?
Do you use any form of focusing aid? If not think about trying a Hartmann mask for a while. There is a how to in the resouces section. Also do you use the IR filter that comes with the DSI? Consider taking it out and see how that goes. Also, if you haven't already, have a look at Ezystyles DSI shots from start to finish and see how far he has progressed in a short couple of months. He is the man to be pestering for info. I don't know too many others who are producing as many images a night as he is atm.
Hey Paul, thanks for the advice. I found focus pretty hard to get spot on {as if i would recognise it anyway} and even when i thought i had it i still get all blurry when i do the longer exp.oopps got my numbers round the wrong way for m13.
I did bring the white point way over when i took the shots. Should i just do that a bit so i can see it faintly then leave the rest of the fixing for photoshop?
What i wouldnt give for a night with Ezy He does the best dsi stuff ive seen.
Maybe i need a wedge as well. He seems to do much longer exp than 30 secs
Ill take any advice folks have {then ill give the same objects a go with my new smarts}
Cheers peoples
If you don't have a wedge, that makes it a challenge for sure. The drizzle feature will help, but it does restrict your exposure time.
I'm not that familiar with the DSI, but the few shots I've taken with it I've not adjusted the white point in the capture program. I've always left that til photoshop.
The attached NGC253 was the first shot I took with the DSI and I basically allowed the program to set the default capture settings. Maybe i just got lucky with the settings, but I do recall focusing was a lot of "fun" You can see though that the default settings clipped the stars. Once that is done there is little you can do as the information that would normally be there has been burnt out
Hi Josh, excellent images for a start and you did great producing a huge collection in just one night. Same goes with my Mrs looking at your images, it seems focusing is abit off. As Paul have said, using a hartman mask will help with your focusing aid. If not, you can try focusing on a bright star instead which i do. Taking images are only worth 40% of a final image, the other 60% is the processing part. It is quite easy to take pics just point and snap but you will need to master the processing. What scope are you using btw? as paul have already said, the star bloat is because of maybe too long exposure (in your case it doesnt apply 30sec) or the white point too low in envisage. My advise is try a 60 second shot in preview mode, untick auto contrast and when the preview image is displayed on your screen, adjust the white/black balance manually instead. Always use preview mode before clicking the 'start' button. Try stacking around 25-30 images and see how it turns out since you are only taking short exposure shots.
I don't use a wedge at all. just using an EQ6 mount.
Programs that i use are:
- Registax (for stacking)
- Photoshop CS2 (processing)
Feel free to ask any questions Josh and thanks for your comments both Paul and Josh. Much appreciated you guys thanks.
Great going Josh, When you think you have focus as good as you can get it take a collection and then try adjusting from your interpretation of the image obtained..you will get to know which way to turn the focuser depending on the shapes in the image... if that makes any sence. But my point is simply take a run either side of your focus and see if they are any better.
alex
Thanks all.
Its funny this astophotograohy stuff, after theach night out i couldnt sleep, just toss and turn thinking about what i could do better.
I think i might give a hartman mask a try, seems like the way to go.
Hey ezy, when your doing your preview do you adjust the white point much at all?. If i dont the image is very faint in the preview shot, is that normal? or do you move it just enough to bring out some detail but stop before the stars get blown out? Do you start with that then bring out all the detail in photoshop?
Its gunna be clear tonight so im trying to get as much of a head start as possible before i head out.
My scope is an LX90 lnt and im in alt/az {no wedge} and use a 3.3 focal reducer
If i dont get the mask made up by tonight{very likely} ill spend more time learning focus with Alex's method.
Thanks again all
Hi Josh, you're going ahead in leaps and bounds.
A couple of things for you to consider;
1. you are doing great with 30 second exposures, you might not benifit much by longer exposures without a wedge. ie. 30 x 30seconds stacked will be better than 1 x 15minute exposure.
2. Hartman masks are fairly popular, and so many people are using them to good effect. I have one but found a good deal of uncertanty still remained so I have gravitated to a diffraction mask. This is rediculously simple to make; two lengths of masking tape across the end of the scope tube or dew shield will work fine, and unlike the hartman mask you don't have to remove it to image.
I have posted an image of Rigel taked @ 15 seconds thru an ED80. The diffraction mask was actually some cotton thread taped across the end of the dew cap. I needed 15 sec to see the spikes, but once focused I can slew to my target and image at what ever exp time I want. ( a thicker mask would need less exposure time).
I don't know what software you have, or if you can zoom in on images, so I have posted a screen shot showing the pixel make up of one of your first Omega images and the last one you posted. I have included the same area of the images, though they are at a different scale, but you will be able to see how the extra exposure time is improving the shape of your star images. More exposure time,(but not necessarily longer individual time) will continue to improve your images.
edited to point out that the lower pixel shot is from your latest image, and the upper is from one of the first images.
Your doing great,
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He does the best dsi stuff ive seen.
You can see though that the default settings clipped the stars. Once that is done there is little you can do as the information that would normally be there has been burnt out
top work
