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Can the Messier Marathon be stacked?

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#1 mpgxsvcd

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Posted 07 February 2013 - 03:54 PM

I am planning on trying for as many of the Messier objects as I can get on the evenings of March 9-11. I probably won’t be able to complete the entire Messier Marathon because the first few objects will set almost directly with the sun. However, I would be happy with getting 100 Messier objects and 10 others(Horse Head, Bubble, Flame, Running Man, Veil, Cacoon …etc).

The thing is that I want to stack them as well. I don’t have the ability to guide so my tracking is limited to about 2.5 minutes. However, for the Messier Marathon you have less than 6 minutes per object so long duration images are not feasible anyway.

Ideally I think I would like to take 4-5 subs of 1 minute each per object and stack them the next day. I know this is not the ideal way to image but that is the point of the Messier Marathon. It is all about quantity.

That doesn’t mean I don’t want to get good quality. It just means that I am trying to achieve the highest quality in 5 minutes or less per object.

I have the option of going to a dark site(Staunton River Star Party). However, I am not certain that I will be able to travel that weekend or not.

So what would be the best choice here? Try for two 2.5 minute subs or just do five 1 minute subs?

I did a test run with my older camera at ISO 1600 last night and here are the results with 4-8 subs.

Stacked 8 of 9 - 1 minute ISO 1600 subs AT8IN 800mm F4.0 + Modified Panasonic GF1

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#2 mpgxsvcd

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Posted 07 February 2013 - 03:56 PM

Stacked 8 of 9 - 1 minute ISO 1600 subs AT8IN 800mm F4.0 + Modified Panasonic GF1

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#3 mpgxsvcd

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Posted 07 February 2013 - 03:57 PM

Stacked 6 of 7 - 1 minute ISO 1600 subs AT8IN 800mm F4.0 + Modified Panasonic GF1

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#4 mpgxsvcd

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Posted 07 February 2013 - 03:58 PM

Stacked 4 of 5 - 1 minute ISO 1600 subs AT8IN 800mm F4.0 + Modified Panasonic GF1

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#5 mpgxsvcd

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Posted 07 February 2013 - 04:07 PM

Stacked 4 of 4 - 1 minute ISO 1600 subs AT8IN 800mm F4.0 + Modified Panasonic GF1

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#6 mpgxsvcd

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Posted 07 February 2013 - 04:21 PM

Stacked 4 of 4 - One minute ISO 1600 subs AT8IN 800mm F4.0 + Modified Panasonic GF1

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#7 Footbag

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Posted 07 February 2013 - 04:22 PM

Guided or unguided?

I would bet that all of the star selecting and calibration that guiding would need would push you not to use it. In that case, can you get 1m subs without guiding? If so, give it a shot.

#8 mpgxsvcd

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Posted 07 February 2013 - 04:23 PM

Here is a single 2 minute ISO 800 sub vs. the 1 minute ISO 1600 sub below.

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#9 mpgxsvcd

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Posted 07 February 2013 - 04:25 PM

1 minute ISO 1600 sub from the first stacked image.

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#10 mpgxsvcd

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Posted 07 February 2013 - 04:40 PM

Guided or unguided?

I would bet that all of the star selecting and calibration that guiding would need would push you not to use it. In that case, can you get 1m subs without guiding? If so, give it a shot.


Yes these are all unguided. I don't guide at all. In fact I don't even hookup a laptop to the scope or mount. I use the camera's live view for aligning, focusing, and positioning.

#11 Sean13

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Posted 07 February 2013 - 06:14 PM

Given your 2 choices you listed I would aim for 2x 150 sec exposures based on the pictures you already posted. If your going to stack make sure to account for the time needed to preform all those stacks. Also time for darks, flat, bias if your going to include those in your stacking as well. Darks will be easy if your doing all the same exposure times so no real reason not to do them.

EDIT: Try 150 sec exposures @ 1600iso if it looks good. If your doing darks you can easily cancel out 150 seconds of noise I would think.

#12 Alex McConahay

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Posted 07 February 2013 - 08:39 PM

It is possible to get all 110 in one night. Of course that depends on time of year, latitude, a lot of practice, a well aligned mount, and a lot of luck. (And lowering your standards a bit on particularly the first and last few).

Do not try it if you expect good pictures. Remember, though, that these pictures will be shown a lot to a page. This means they will be relatively small and forgiving of some errors.

I actually used a cooled CCD camera, and LRGB shots. I think 60:40:40:40, (I think) but in the middle of the night I shifted to even shorter exposures because I realized I would run out of time otherwise.

With a OSC camera, I would go for three one minute exposures. Each will have fifteen to twenty seconds of download, etc. That is about 240 seconds. You only have 313 seconds per object in my calculations (which depend on latitude, and how much you want to nudge into twilight). This leaves you with about 70 seconds to slew, futz, focus......In addition, unless you can plate solve, or have a mount with perfect pointing accuracy, etc....you will have some aiming problems. (Of course with the wide field of a DSLR and a short focal length, you can miss by half a degree and still get the shot.) Focusing occasionally and general screw-ups will take some of your time. Of course youcan pick up some of that time by double imaging (M42/43, M31 and Friends.)But otherwise it is just carefully going through your list. Make sure your list is not the same you would use on a visual Messier Marathon. Re-write the order of imaging to minimize slewing, and particularly meridian flips.

Alex

#13 end

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Posted 07 February 2013 - 09:10 PM

I'll be trying for the same thing. My plan will be using my C11 in Hyperstar mode - so only 560mm and a fast f/2. While in principle we have about 6 minutes per object, I'm planning on doing just 5 x 30 second unguided exposures to give myself a bit more flexibility. It also gives me the chance to throw out an unlucky frame if necessary and also means there is no need to guide.

In my opinion, other than clouds (and endurance) which could obviously ruin everything or block out a substantial part of the night, the only real difficulty will be M30 which rises only slightly before dawn. I expect any image I get of M30 will be pretty ugly.

#14 avarakin

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Posted 07 February 2013 - 10:07 PM

I am thinking of doing MM but without goto with 135mm (maybe 300mm)lens. This should be pretty easy and fun.
Alex1

#15 mmalik

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Posted 08 February 2013 - 04:06 AM

Some of my thoughts:

1. Hypothetically speaking if you were to cover 110 objects in 8 hours of darkness (one night), you’ll have ~480 minutes; 480/110=4.36. Your 5 min/object estimate is close given you might not get all if few set with the sun. What this means is you really wouldn’t have much time to spare if you were to plan 5min/object. 4min/object “may” give you some time to spare for any slewing/pointing/outage/troubleshooting, etc.

2. 4x1min at ISO1600 sounds about right given the time crunch we are talking.

3. You’ll probably need to squeeze in few darks; may be ~10x1min at ISO1600. You could do them at the end of the session if temp difference will not be large, instead of squeezing them between shots and increasing potential for any mishap/downtime.

4. You would want to start in the west to image the ones close to setting first and work your way eastward.

5. Do your homework ahead of time to arrange objects in such a way so there is least slewing needed from one to the next; again starting from west to east.

6. Also arrange objects in such a way so you do meridian flip only once (western to eastern hemisphere).

7. Your mount’s pointing would have to be nearly perfect; if you are going to a star party then rehearse how quickly you can get your mount setup/pointed early in the evening.

8. You probably will need to re-align (sync) your mount along the way for accuracy; build those re-align stars in your homework with least slewing.

9. Confirm each object at least once (preferably after the first [of four] shot) in the live view to make sure you are on the right object and that it is roughly centered.

10. Plan power accordingly so you wouldn’t have to mess with batteries for any component.

11. “Wheels up”; try not using a laptop; save images locally on the bigger/faster memory chip; only exception would be the external power supply to the camera, if applicable.

12. “Fly by wire”; once mount is pointed, try not using visual cues for anything; live-view should be the guide for centering/framing/aligning, etc.

13. “No touch”; try only sparingly touching your setup once setup; verify images post exposure by setting may be 8 sec review so no manipulation is required.

14. Build focus check points into the plan; lesser the better.

15. Homework/plan is also important for post processing to know what is what once done.

16. Etc... I could go on and on but will stop.


One a side note, mount tools like this... come in handy in all situations.

Thx

#16 Yoddha

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Posted 08 February 2013 - 06:35 AM

Mmalik gathered great list!

I also think that 4-5 exposures of 60s is the best option. You will have more images and will be able to reduce the noise better. Try sigma-clipping staking method.

Very interesting project!

#17 ahopp

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Posted 08 February 2013 - 08:02 AM

Travis,

I think it is great, the amount of time and planning you are putting into the marathon. Hope it all works out for you.

I will be at the Start Party next month, sorry to hear you are going to go it alone.

I will, however, see you tomorrow at Jordan Lake to play with our cameras, your Panasonic and my Mallincam Xtreme.

Again, great start on the marathon.

Tony

#18 mpgxsvcd

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Posted 08 February 2013 - 10:48 AM

Great advice everyone. I think that I will probably have to go with the 4-5 one minute subs option. My scope has been having focus issues lately. I can easily get it in focus. However, one of the components seems to be cooling at a different rate from the others.

I have been seeing the focus steadily go out over a series of five 1 minute photos lately. It appears to go out of focus linearly which indicates that it is not a sudden slip issue.

I need to have the ability to see every image as soon as it is finished to confirm focus.

I actually will be using a camera that will automatically transmit every RAW+JPG image over wifi to my laptop. I plan on controlling the mount and camera via wifi from smart phones. I will probably just sit inside my tent and monitor the phones to make sure everything is looking good.

Since I can get the images in real time directly on my laptop without cables I might even try to stack most of them while I am imaging. However, I think the fast pace that the messier marathon entails will require me to concentrate on imaging. I might just do the stacking the next day if I am still awake.

I still might go to Staunton River. I am just not sure if I can get away for several days. I also don’t want put the red filters on everything. I don’t use eyepieces at all so dark adaption is not an issue for me. However, I don’t want to make everyone mad at the star party either.

If I can run everything from within the tent and mask the light pollution that I might create then I will probably go up there. If not I will just go to s semi dark site where I won’t be bothering anyone else.

Tony,

I am sending you an email about this weekend.

#19 Alex McConahay

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Posted 08 February 2013 - 12:12 PM

Seriously, do the math....you do not have enough time to spend five minutes with the shutter open on each object. Especially if you plan to focus now and then, spend any time slewing, pointing, correcting, etc. And if you are actually downloading the images, you have to add that to the exposure time (at least with all the software I know about). (You are shooting RAW, right?)

If you do insist on starting out with five shots of one minute each, be prepared at ten o'clock or something to reduce the number of shots per object or reduce the exposure time per object. Keep track of where you are so that you are half finished before the evening is half over, etc......

Do not try to stack the images while you are capturing them. WHile it seems that you have plenty of time to just sit there while your camera is working, in fact there is note taking, checking on things, preparing your mount for the next slew, changing the file names (if you are using capture software) and checking your exposures as they come off the camera. All of this takes concentration. And every sixty seconds (or something) you have to break and look at your exposure.

Oh, and since this is not a Hollywood movie---remember there will be at least once, you can figure, when you will want 45 seconds away from the setup to go to the potty!!!!!

Before I did my marathon, I actually "trained" for several months, trying to get 12 objects in an hour. At first I could only get two or three. Finally I worked out the kinks in my plan. That included some silly things like where I positioned my computer on the desk, how the various sub windows and menus were positioned on the screen(s), where the focuser controller was positioned, changing the size of the list of objects.....all sorts of silly things you do not have to think about when you are not actually doing something so strange as trying to capture all 110 objects in one night.

>>>>>I need to have the ability to see every image as soon as it is finished to confirm focus.

Dude, reconsider. This is a deal breaker. You are not just trying to run a marathon, you are running it in steel-toed boots with a Hazmat suit on. If your equipment is not working right, it is a great challenge.

Alex

#20 Footbag

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Posted 08 February 2013 - 12:22 PM

>>>>>I need to have the ability to see every image as soon as it is finished to confirm focus.

Dude, reconsider. This is a deal breaker. You are not just trying to run a marathon, you are running it in steel-toed boots with a Hazmat suit on. If your equipment is not working right, it is a great challenge.


Why is that a deal breaker? Doesn't everyone review their images as they come in? :question:

#21 bunyon

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Posted 08 February 2013 - 12:27 PM

I've never imaged a MM (have visually done one), but one thing you should note is that some objects don't even need 1 minute. You can get a perfectly respectable shot of M13, for example, with a 20 second exposure. Ditto for many of the brighter open clusters. That would free you up to shoot longer on the fainter objects.

Though I agree with footbag, that 5 minutes per objects sounds way too long.

#22 Alex McConahay

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Posted 08 February 2013 - 12:33 PM

>>>>>Doesn't everyone review their images as they come in?

Yes, under normal circumstances. (Actually, no......many people are asleep while their automated scopes/camera work away. But, really, most of us want to see what we are getting.)

However, this is a marathon. You are not under simple rules. The point is, if you do not trust your system enough to stay focused for an hour at a time (or point within a few arc minutes, or.......) then you will not have time enough to get this thing done.

Or--to look at it another way--what do you do if the exposure did NOT work? (bad focus, etc.....) You have to retake that shot? You have to spend time refocusing? Well, those minutes do not come back in some kind of "extra time." Nobody is gonna make the sun stop coming up.

The dealbreaker is not looking at the exposure as it comes in, it is in not having gotten the equipment to the point that it will do exactly what we want it to do. If you cannot trust the focus, you won't survive the marathon.

(By the way--remember, the point is not great full screen poster pictures of each object. The point is getting them all in one night. When you display them later, they will be displayed smaller than your other photos. SO, you can forgive some things that would be unacceptable in normal imaging. )

Alex

#23 ahopp

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Posted 08 February 2013 - 12:42 PM

I still might go to Staunton River. I am just not sure if I can get away for several days. I also don’t want put the red filters on everything. I don’t use eyepieces at all so dark adaption is not an issue for me. However, I don’t want to make everyone mad at the star party either.

If I can run everything from within the tent and mask the light pollution that I might create then I will probably go up there. If not I will just go to s semi dark site where I won’t be bothering anyone else.


Travis,

You can put your setup inside my mobile observatory if you want, let me know.

Tony

#24 Footbag

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Posted 08 February 2013 - 12:43 PM

Ok. So it's more about focus, maybe the newt will require more frequent focusing.

When all is said and done, I could see a poster with a grid on it with 300x300 images of each target. By down scaling, you will clean up all of your images as well.

#25 mpgxsvcd

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Posted 08 February 2013 - 01:51 PM

A couple of things. Temperature variances can affect focus especially with the Newtonian I am using. That is the only reason I say I need to be able to check focus.

One I set my focus it usually has no issues. However, I can't predict what temperature swings there will be so I want to be prepared for the worst case.

The other thing is that my camera has wireless built-in. Therefore, every time it takes a shot it can automatically upload both the RAW + JPG file to my computer or just display the JPG on my phone.

If I have it display the jpg on my phone it will show a reduced resolution image that matches my phones resolution. It is sufficient to check for major focusing issues. However, it is almost instantaneous because the file size is so small.

I am not worried about being able to do it with my setup. I tried it the other night with one of my older cameras and I was able to get at least 4 images of 12 objects per hour. I plan on doing less images for objects that are much brighter. Since there are so many clusters that will give me some leeway on the darker objects.






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