Novice astrophoto questions - several

[smasraum]

I'm just starting to tinker with shots of the heavens. Star trails are pretty easy, and snapshots of the moon are pretty easy, but I'm starting to try to capture stuff like nebulae, planets, etc.... I'm pretty limited in my equipment working with a steady, heavy tripod, 350D, and Sigma 70-300 APO. So I can't track stars which unless I want to do star trails, makes my exposure time pretty limited.

I've got some shots of the Orion Nebula, that are ok, considering.... But I think there's a lot more for me to learn. I've searched the forum and the web and read a lot, but a lot of the stuff that I've read comes from folks with Sky 90s and motorized equatorial mounts. Some of my questions, I think, are more specific to someone that's limited by not being able to track.

I'm trying to experiment with stacking. I've downloaded Registax v4, and DeepSkyStacker. I've tinkered with Registax, my PC was groaning under the strain, and the learning curve is pretty steep. Should I stick with singlepoint or multipoint, use gradient or local contrast, etc...? Any tips that yield decent results?

I've also got PS CS2. What's the best method to stack in CS2?

What sort of images are better to stack an image with more visible detail and more noise, or less of each? At 1/2 and 1 sec at 300 mm there's not a lot of trail, but the images are pretty dark and detail is less. I can crank up the exposure in DPP and get more detail, but then, of course, I get more noise. At 2 secs, I get trails, but there's more detail and noise. Since stacking increases detail, is it better to start with an image with less detail and less noise, or visa versa? Also, does the motion visible in the 2 second shot, wipe out the detail that I'm looking for?

Once the moon starts rising in the early evening and I have this stacking thing down, I'll see what stacking does for moon shots, but the darn thing rises so late right now....

to recap
1 setting/process recommendations for registax, deepskytracker, other software?

2 what's the stacking process for using PS CS2

3 what images to use for stacking, lower detail lower noise, or noisier, brighter images?

4 Any other pointers that you might have for questions that I haven't asked because I don't know enough to ask. ;)

Thanks all.

PS This seemed like a really weird place to put this thread, but most of the astrophotography threads seemed to be in this forum, so....

[evorgsumaf]

I have never really tried this type of photography, but I really REALLY like everything that "nighthoud" has posted here. To me, he seems to be the resident expert in that area. Do a search for his posts, and that should give you a head start.

I hope that helps.

[Harold_L]

Steve, you have obviously put a lot of thought into your question already. There is a vast amount of literature about taking astro-photographs, which have led you further than this forum is likely to. To jump start yourself, I would suggest that you give up any idea of using your 300 mm focal length for the present time. The problem as you already know is that you need to get enough light to your images, meaning using exposures of at least 15 seconds. Interestingly enough, you may have better results by using short focal length lenses, such as in the 30 to 50 mm range. This will give much larger fields of view, and minimize the image drift. In a dark sky, you can reach at least 6th magnitude stars with a single 15 second exposure at f2.8. At that point, you can try the advantage of stacking images. Unfortunately, I think that it just is not practical to try deep sky images with even 1 second exposures. If you are serious about getting deep sky images ( 9th magnitude or fainter), you are just going to have to have of some sort tracking. This doesn't necessarily need to cost a lot of money. For example, look into the so-called "Barn Door" hinges mounts that have been successfully used by many amateurs.

Have a lot of fun with this project.

Harold

[R Hardman]

Start by taking wide angle constellation shots. Use ISO 1600, aperture as wide as you can go and keep the exposures short to minimize drift. At 17mm you can go up to 30 seconds without to much drift. Take at least 3-5 dark frames to get a quality master dark frame and for your light frames the more the better (30+) As for stacking use multi-point. The more alignment points the better your stack will be. I would not use CS3 to stack as star fields rotate and trying to align it in PS is a nightmare (used to do it in PS5). I also use Registax v4 and DeepSkyStacker and found DeepSkyStacker works better for star fields. If your out after midnight tonight, catch the Quadrantid meteor shower. Should see 120+ under dark skys.

[smasraum]

Thanks guys.

I've taken some wide angle stuff, but mostly for trails, and even stacked some (to make the trails longer, not improve the SNR) I'll try some of the wide shots too using my nifty 50 and the kit lens. I've got a couple shots of pleiades, orion, and taurus that I took when tinkering, but the wider stuff seems like it's worth working on more.

I'll continue to do more reading, and I'll give Registax a rest and tinker with DeepSkyStacker some.

When taking multiple dark frames do you stack them or process them individually?

I have had a reminder set in my calendar to go look for meteors tonight. At 2130, it was clear, at 0030, it was completely overcast. That's always my luck. In the last 2 weeks I've seen several meteors, but each time I didn't have my camera going.

Here is a shot of Orion that I took last night. First one of individual frames with minimal processing and then the just stacked not processed image from 5 of those individual shots stacked. I think I did start to see the hint of better detail and more color in the stacked shot, and like I said, I didn't finish processing. I suspect 20 or more shots may be better. But still, I suspect that you can only do so much when you have limited data to work with.

Both shots were cropped down to about 1600x1700 and then resized to half of that size.

Thanks again, keep the advice coming.

[Nighthound]

Welcome to the extremely challenging and rewarding field of astrophotography Steve. It's great to see your enthusiasm and research efforts to get a leg up on the technicals.

Some great info and recommendations shared above. Without tracking capability, as you are already aware, you'll be best served to shoot as low a focal length as possible with as fast a focal ratio lens as you can, under the darkest skies you can find. Most deep sky objects require hours of data to do them justice. There are some bighter ones like M42, M31(Andromeda Galaxy), M45(Pleiades) that are great places to start and see some pleasing results as you've already done in your shots of M42. As Harold mentioned there are ways to construct a barn dopor tracker if you are so inclined, I've seen some good results and it's certainly a way to get started at very low cost.

I've been hard at this for about 5 years. I started by shooting Lunar and planetary and then got the deep sky fever. Mainly because of the awe of capturing such ancient, distant/faint light and seeing it come to life on the monitor during processing but also because of the variety and huge number of targets available. The learning curve is a long and steep one but with persistence, patience(a ton) and practice you can make progress fairly quickly. Before I talk processing let me add some shooting tips.

I can't emphasize dark skies enough. Light pollution is the enemy of the faint light you're after. Poor seeing conditions, poor transparency, wind and dew/frost also top the list of obstacles. I shoot fom a couple of different dark sites, just too much light at home. I travel between 20 and 45 minutes to much improved skies and I still use a Hutech IDAS Light Pollution filter with my scopes.

Do everything you can to make your tripod more sturdy, even suspend a weight from the center below if you can rig one. Use mirror lock and a shutter release cable, at very least use the camera delay timer. Find your focal length limitations for exposure time and shoot at either 800 or 1600 ISO. In the colder months you'll get much less noise at 1600. I stick to 800 in the summer or reduce exposure time at 1600.

Before I forget to answer your question concerning movement and its effect on the image, yes. The result is detail blur just as if you had shook the camera during a daylight exposure. This is why accurate tracking is so citical to producing quality astrophotos. It also allows for longer exposures which means you're going deeper, gaining structure detail and color. The longer and deeper each subexposure is the better the final image will be. And of course proper processing will be essential to make the most of your hard earned data.

The last thing I want to do is discourage you in any way but don't expect too much from subexposures that are 5-15 seconds. You can stack hundreds of them and thy won't show you much more than a single exposure simply because stacking doesn't create data that isn't there. To simplify, stacking raises the signal to noise ratio. Bringing out the detail/color while reducing the noise created by long exposures and high ISO settings. So if the fainter stars, for instance are not being captured to start with, stacking can't reveal them. I stack in Images Plus and stretch the stacked image in Photoshop CS3. I also use Noel Carboni's Astro Acions for Photoshop(AWESOME) and highly recommend them. I really know nothing of the programs you mention so I'm sorry I can't help you with their settings.

I'm one of those Sky 90/equatorial mount types but I also shoot with a Vixen R200SS newtonian which gives me double the focal length of the Sky 90 but also requires my mount to be on its best behaviour and for me to be at the top of my alignment game. So even with a mid range mount, I still have to deal with drift and periodic error caused by imperfections in the mount's gears. The Sky 90's low focal length(407mm with reducer) is much more forgiving and really gives some great field of views matched with the 5D.

You are off to an excellent start and I know with practice you'll sharpen your technique and produce even better images. You're tackling the most difficult type of photography there is IMO, and I shoot a lot day and night, but for me the challenge sweetens the successes. Please feel free to fire questions my way, I had a lot of help from others more experienced over the years and it has helped enormously. Clear skies!

NH

[smasraum]

Thanks Steve.

[smasraum]

I was curious, so I did a seach for diy mounts/trackers and found some pretty cool links. (hopefully they'll help me and maybe anyone else that finds this thread). It's pretty funny, right now I'm at that point where the more I learn, the less I seem to know. Hopefully I'll have some time for reading research and practice and will be able to feel like I'm making progress soon.

DIY double barn door tracker.
http://education.jlab.org/tracker/index.html

Astronomy & Astrophotography Tips
Getting Started, DIY Projects
Cameras, Observation Guides, Techniques, Telescopes...
http://www.knowledgehound.com/topics/astronom.htm

There are scads of links with diy mounts. Thanks for the tip, that's something that I can and will do (when I can fit it in between the other "honey-do" stuff).

This is all very exciting.

Thanks again for the help folks.

[Harold_L]

The two Steve's are certainly firing my interest again. I have an equatorial mount, which I have mainly used for solar h-alpha photography. I have never built a barn door mount, but I am laying the plans now. It will use the simple isosceles triangle design - I have an idea for making a swiveling nut for it. Perhaps it will be done in time to still get wide angle images of Comet Holmes.

Cheers,

Harold

Harold

[smasraum]

Harold, you may want to "adjust" your signature. :D

Yeah, I want to make one, but I have to do lots of other crap around the house first. I guess it's that much more motivation to get the house stuff done quickly.

Steve

Steve

Steve

Steve
;)didn't want Harold to feel singled out.

[Madweasel]

I'd like to get a decent equatorial mount, but in the mean time (and for some years on and off now) I've been using a modified timer switch from a street lamp, which has a spindle turning once in 24 hours. I had to make it go the other way first, but as it's driven by an ac motor that was easy. I've mounted a ball-and-socket mount on the shaft and I've found that by lining up the axis purely by eye I can easily get sharp shots at 200mm for 30-60 seconds. Even in my back garden with quite a bit of light pollution, ISO 1600 and f/4 can get me to magnitude 13 or 14, which is great. I recommend trying a cheap way of providing a driven mount, as it extends your range enormously.

[Harold_L]

Mark, that seems to me to set the record for the simplest tracking mount I have ever heard of! Can you show us examples of your astronomical images using this system?

[smasraum]

Mark, that seems to me to set the record for the simplest tracking mount I have ever heard of! Can you show us examples of your astronomical images using this system?

And show us your mount?

[Mike-DT6]

Excellent thread! Thanks for posting the good information everyone! A couple of nice images there too, Steve.

Mike

:-)

[smasraum]

Another good link that I've found.

http://www.astropix.com/HTML/I_ASTROP/TOC_AP.HTM

And some stuff straight from Canon
http://web.canon.jp/imaging/astro/index-e.html

and another about the Canon
http://www.covingtoninnovations.com/dslr/EOS300Dastro.html

[Madweasel]

Mark, that seems to me to set the record for the simplest tracking mount I have ever heard of! Can you show us examples of your astronomical images using this system?

And show us your mount?

OK guys, here it is.
http://i72.photobucket.com/albums/i192/garlicpickle/Canon/DSCF1025.jpg

I took all the switch stuff off the top of the timer (it had a very clever cam system to change the switching times through the seasons), and had a brass shaft fixed over the original, with a 1/4" thread on, for my ball and socket mount:
http://i72.photobucket.com/albums/i192/garlicpickle/Canon/DSCF1027.jpg

Then I mounted the switch to a piece of wood and under the wood fastened a Manfrotto quick-release plate:
http://i72.photobucket.com/albums/i192/garlicpickle/Canon/DSCF1026.jpg

Then I fastened the whole thing to a large ball-and-socket head on my very large Manfrotto tripod. Then I can aim the mount towards the Pole Star and mount the camera on top of the whole thing:
http://i72.photobucket.com/albums/i192/garlicpickle/Canon/DSCF1028.jpg

And here's a 60s exposure at 200mm, to show how good the tracking can be (though it can also be a bit hit-and-miss). Sorry there's still some light pollution showing, but I'm still learning the PP for astrophotos and I'm not very good at it yet. If you study the picture, there's a little of the nebulosity showing and the faintest stars are magnitude 13-14.

http://i72.photobucket.com/albums/i192/garlicpickle/Canon/IMG_0092aweb.jpg
Thanks for your interest!

[Perry Ge]

This is an excellent thread. I've got a Meade LXD55 6" SN sitting at home in HK, I'd love to get some astrophotography done with it, because the mount is awesome, but there's just way too much light pollution and well, pollution, period, in Hong Kong most of the year :(.

Autoslew equatorial mounts really are awesome if you are willing to shell out for them, though Mark's method looks awesome too if you put in the effort!

[Harold_L]

I found that the forum name had changed, after a bit of search. Thanks for the good images of your 1 rev/24 hr motor and attached camera mount. That is truly the extreme of simplicity. It would be neat to see this posted on one of the astronomy technique sites.

Cheers.

[smasraum]

Mark, it looks like the hard part of your setup would be getting that thing aligned/polarized initially. But looks like it works great based on your photo.

Yes, starting to see the nebulosity of Pleiades (sp). Very nice. You could maybe change your white balance to flourescent, and that would change your red/orange to blue. Also, I haven't used them myself, but I hear that "Astronomy Tools" for Photoshop work well, and they are only $20. I suspect that there's probably something in the bundle to help you with your post proc work.
http://actions.home.att.net/Astronomy_Tools.html

[mellowd]

I'd like to get a decent equatorial mount, but in the mean time (and for some years on and off now) I've been using a modified timer switch from a street lamp, which has a spindle turning once in 24 hours. I had to make it go the other way first, but as it's driven by an ac motor that was easy. I've mounted a ball-and-socket mount on the shaft and I've found that by lining up the axis purely by eye I can easily get sharp shots at 200mm for 30-60 seconds. Even in my back garden with quite a bit of light pollution, ISO 1600 and f/4 can get me to magnitude 13 or 14, which is great. I recommend trying a cheap way of providing a driven mount, as it extends your range enormously.


Do you know where I can get one of these timer switches? I'd love to try this

[ebann]

Get a nice German Equatorial Mount, at least Meade's CG-4 Heavy Duty for about $220. CG-5 if you can afford it. Get the axis motors later on once you get tired of manually tracking stuff.

Get a small refractor telescope or a Newtonian (Meade kit with the tripod) so that you can use Celestron's NexImage imager ($153). Why? Definitely not to substitute your DSLR, but to use it to do a simple polar alignment with:

http://wcs.ruthner.at/index-en.php

You might need extra connectors to attach your camera+lens to the mount. These are a few things you might consider:

(1) Here is the "KD Astroview Dovetail Saddle Adapter" ... http://www.kendauzat.net/other/1126071b.jpg ( $95 plus $10 P&S ) ... especially designed for the Astroview that will allow the use of a standard CG5/LXD55/75, and GP type dovetail bars.

(2) The dovetail bar with a 1/4" x 20 countersunk camera treads is $38 plus $6 P&S.

(*) AstroView is Orion's rebranded name for Meade's CG-4 and SkyWatcher EQ3-2.

I basically use my TeleVue Ranger+NexImage on my AstroView mount for polar alignment. Then I swap the Ranger for my DSLR+lens for astroimaging.

[Harold_L]

Mark, I converted your Pleiades photo to monochrome using a green filter, in Picture Window Pro, and then boosted the gamma slightly. It makes a very attractive image in black and white. If you want, I could post this image under this thread.

[Madweasel]

Mark, I converted your Pleiades photo to monochrome using a green filter, in Picture Window Pro, and then boosted the gamma slightly. It makes a very attractive image in black and white. If you want, I could post this image under this thread.
Go for it Harold!

[Kadath]

I'm shocked that nobody has put out a consumer level kit yet that takes the simplicity of the mead trackers but extends it to something that a DSLR user could use with a 200mm or smaller lens yet. There is a huge market for this from people like us who want to track and shoot but want to leave the math and hard work to the people who live for this stuff. Laugh all you want but there is a true unsatisfied market there.

[Harold_L]

Mark, here is the black and white version of your image. I see at least two areas of nebulosity in the Pleiades.

[smasraum]

I've got another question. Most of the time, I don't have time to drive to someplace dark and just run out before bed when the sky is clear. So I'm usually fighting major light pollution. I assume that in this case the best way to get as much detail as possible would be to err on the side of overexposure ending up with an image that has lots of LP and therefore, not a black sky, but more info about the stuff that you are shooting.

Is that a correct assumption?

Next question, is what techniques/tools would be used to turn the image into something useful without losing too much of the detail that you're trying to catch? Actually, it looks like Harold has a pretty good handle on it. I think that the "Astronomy Tool" set of photoshop actions would also be useful, and the price almost can't be beat.

Thanks.

One more question, what's the best way to get rid of gradiant stuff in the background (darn light pollution)?

[Madweasel]

I've got a lovely smug grin on my face right now. I've been fiddling in Photoshop for a bit and here's what I've got from the very same shot I've already posted (now cropped a bit to show the most interesting part).

http://i72.photobucket.com/albums/i192/garlicpickle/Canon/IMG_0092blackweb.jpg

I just called up Levels and used the black point dropper and pointed it at a piece of sky that should be black. It took away all the background light and left me with correctly-coloured stars and the nebulosity is clearer than ever. I think there was some beginner's luck because I've had trouble repeating it with such good results. I'm still experimenting!

[smasraum]

Mark, cool, I'll be tinkering all weekend. Last night was cold and clear. I stayed up WAY too late taking photos of stars and tinkering with stacking. I think tonight will be similar, but at least it's Fri this time.

[smasraum]

Mark, you never did say (or did I miss it) how/where you would get one of those timer/motors.

[Madweasel]

Mark, you never did say (or did I miss it) how/where you would get one of those timer/motors.
Well I'm not really sure what to advise. I think these switches were an expensive way to do it, compared with how cheap it is these days to make street lights switch on a light-sensitive switch, so they just come on when it's dark. I must have got this switch about 25 years ago and I actually went down to the council yard and asked if I could have one! It's made by Sangamo Weston (I think), so maybe a search on them might turn something up.

Any motor with a 24-hr output shaft would do it. I know that for a telescope you need proper sidereal rate, but for a minute or so the error is smaller than other errors in the system, such as polar pointing accuracy and even drive vibrations. I'd love a decent equatorial mount, but as others have said, they seem so expensive for what they are.

[Harold_L]

Wow, Mark! Isn't processing wonderful! I'm going to go back to your original image, and see if I can replicate your new results using Picture Window Pro.

Harold