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Camera Settings for a Beginner

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#1 Jehujones

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Posted 02 December 2021 - 12:08 AM

Can anyone help me out with suggestions for camera settings?

I'm a very simple beginner with very simple tools.

 

I'll be in a Bortle 4 location this weekend with a 12" F4.9 scope.

I have a Fujifilm XT-10 body at prime focus.

My mount is non-eq and tracks alt-az (field rotation)

 

I really would love to image M33 but I have no clue what ISO or Shutter speed to use.

 

Are there maybe better galaxies to try instead?

M31 is too big to fit in the frame which seems to be about 45" x 30" or 3/4o x 1/2o

 

I appreciate any help



#2 daveco2

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Posted 02 December 2021 - 01:20 AM

Here's a good website where you can see an M33 sample.  Looks like iso 800, 5 minute exposures would be a good place to start.  That's a pretty long focal length.  You'll need good tracking.

https://www.galactic...iangulum-galaxy


Edited by daveco2, 02 December 2021 - 01:21 AM.

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#3 TelescopeGreg

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Posted 02 December 2021 - 01:33 AM

I'm thinking it's going to be tough.  I'd start with a really high ISO (like, max it out) and see what you get with a short exposure (few seconds?).  See if you can get the peak the histogram on the back of the camera to move off the left edge a bit (ideally 1/4 of the way), and see if the stars are dots or wiggles.  Keep lowering ISO and lengthening the exposures, as long as you're getting dots.  If you get to an ISO around 800 (or whatever is best for your camera), that will be good - best noise and dynamic range combination.

 

I don't think rotation will be your problem, rather the lack of the proper mount and guider might prevent a long enough exposure without star trails.  My 8" f/5 scope needed exposures around 20 seconds and an ISO set to 6,400 to do deep sky imaging at my Bortle 6 location.  But that's with an Equatorial mount and an autoguider running, 1,000mm focal length not ~1,500, and even so I had to toss about 10% - 20% of the subs due to motion.  The mount simply wasn't able to control the telescope well enough to go any longer.

 

By all means give it a try, but...


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#4 Jehujones

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Posted 02 December 2021 - 01:44 AM

Thank you so much for the advice and the link. Yes, I agree about the mount issues. The scope in question is the Orion XT12g. It can keep a target in a low power EP but I think that’s the limit.



#5 bobzeq25

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Posted 02 December 2021 - 02:05 AM

Can anyone help me out with suggestions for camera settings?

I'm a very simple beginner with very simple tools.

 

I'll be in a Bortle 4 location this weekend with a 12" F4.9 scope.

I have a Fujifilm XT-10 body at prime focus.

My mount is non-eq and tracks alt-az (field rotation)

 

I really would love to image M33 but I have no clue what ISO or Shutter speed to use.

 

Are there maybe better galaxies to try instead?

M31 is too big to fit in the frame which seems to be about 45" x 30" or 3/4o x 1/2o

 

I appreciate any help

You've got way bigger problems than camera settings, unfortunately.

 

You're going about breaking into DSO AP in an _extremely_ difficult way.  The nonintuitive nature of this makes that very common.

 

The mount is the most important part of the setup.  And ones that are good enough are expensive equatorials.

 

Even on one of those, a big scope makes like very difficult.  Great for visual, lousy for breaking into DSO AP.  For many reasons, not the least of which is that it magnifies tracking errors coming from the substandard (for DSO AP) mount.

 

The ideal setup for starting out in DSO AP is a small refractor on a good German equatorial mount.  That's about $2000.

 

The economical alternative is to shorten the focal length, a whole lot.  Instead of the big scope, you'd do _much_ better with a camera lens.   That can be mounted on a simple equatorial tracker, about $300-500.  The setup looks like this.

 

https://astrobackyar...ra-and-lens.jpg

 

This book has a lot of useful information.

 

https://www.amazon.c...d/dp/0999470906

 

This bears almost no similarity to visual astronomy.  Long exposures totally change the game.  That explains the style of this quote from Dr. Craig Stark, noted astrophotographer who writes and lectures on the subject.  He's interacted with a lot of beginners.  Dr. Stark, on a good scope to start out with.

 

"As light as possible."

 

 

 

Seriously.

 

 

 

No, seriously."

 

A camera lens is about as light as it gets.  <smile>


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#6 imtl

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Posted 02 December 2021 - 04:16 AM

Fellows, the OP is asking what is recomended to do with the current setup. Not, what should be with an ideal setup for beginners.

To the OP,
As suggested, try highest iso and short 10s exposures and see how an hour of integration (total time not single exposure) looks like.
Did you make sure that you can reach focus with your scope and camera? That is usually the biggest problem with Newts that are not designed for AP.

Try and enjoy the experience and don't worry too much if it fails. You'll learn from this in your way.
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#7 Jehujones

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Posted 02 December 2021 - 10:04 AM

"...You've got way bigger problems than camera settings, unfortunately....

 

...The ideal setup for starting out in DSO AP is a small refractor on a good German equatorial mount..."

 

Agreed, and eventually I will probably join the club, so to speak.

 

 

"...Try and enjoy the experience and don't worry too much if it fails. You'll learn from this in your way..."

Thank you all for the info and suggestions. Indeed, right now I'm just messing around with what I have and not trying to impress anyone but myself. I realize that I'm asking a mule to run a race. I got curious last year and wondered what would happen if I stuck my camera on my 10". I really didn't know what to expect and I didn't take notes on what I did for exposures. When I got an image of C2020 Neowise I was so excited smile.gif I've always been a visual observer. Here's a single frame image without any tracking at all...

 

image_2021-12-02_065859.png

 

Thank you all again, I will try the suggestions and if it doesn't work I can always stick to bright objects for now.

 

Clear skies


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#8 Alex McConahay

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Posted 02 December 2021 - 11:08 AM

If in fact your big old scope is in fact tacking well in Alt-Az, you can grab a picture. Your limitation will be what is called field rotation. So, you need to choose targets and settings that combat Field Rotation.

 

Before you start, check this out:

 

https://telescopemou...-great-results/

 

 

Now, I am going to assume you are not guiding. (The article quoted above assumes guiding.) You cannot just follow the suggestions there. 

 

But, whatever you choose as a target needs to be something that will suffer the least field rotation. The closer you are to the celestial equator and to the meridian, the more your scope will experience field rotation. So, choose a target that is as far north (or south)----highest declination numbers)  as you can and as close to the eastern or western horizon as possible. Of course, try to keep it above 20 degrees altitude to avoid other problems----imaging at a horizon brings bad seeing, light pollution, and all that.

 

Field rotation shows up more in stars than in nebulous objects. This is just because nebulosity is fuzzy, and stars are pinpoint. Pinpoints show streaks sooner. So, choose things that have more nebulosity than stars. (of course, no matter what, you will have stars). On the other hand, stars are a lot easier to get pictures of. They tend to be a lot brighter per arc second. So, choose things that have more stars than nebulosity. (Yeah, I know I went both ways on that........but those are your choices.) 

 

And, yes, you want bright objects. Those that show lots of light per square arc second. You cannot tell by just using "magnitude" of a target, since that is a composite of all the light in the area that comprises the target. YOu want high "surface brightness" targets. 

 

At 1225 focal length, you have a medium long scope. So, choose things that fit your field of view. To check out your Field of View, go to Telescopius.com, and use their telescope simulator with your scope and camera. Then, page through the possible targets.

 

So much for targets. 

 

As far as exposure, you have to remember that the big problem for you is field rotation. This shows the longer you run your exposures. SO, you want short exposures.

 

How do you get shorter exposures? You up the gain, or ISO.  Go for as high as you can reasonably go and still get at least some usable dynamic range. (And if noise is a problem at high ISO/gain, then back off.) And remember, while it is best to avoid shot noise, it can be dealt with also in processing. So, maybe accept more during acquisition, and work on it harder in processing. 

 

How short should your exposures be? As short as you can get them and still rise above the background noise. How long? As long as you can go without showing field rotation. Try ten seconds. Then twenty. And continue as long as when you look in the corners of the frame, you do not see objectionable trailing or eccentricity. And remember, when you change target position, you change the rate of field rotation, so what is good for one celestial target is not good for another. And remember, as you are looking at them on your computer during the session, they will all appear dark. YOu must apply a screen stretch to see what you are really getting. 

 

How many exposures? As many as you can get in an hour or two. 

 

May I suggest another tack? EAA.  Using SharpCap (which is free--but I do not know if it will work with your camera) you can monitor how all this is going in real time. All the stuff I said about field rotation and exposure time still applies. But, you are watching the image build as you go. You may find it much more productive than the traditional way we do things in general in deep sky imaging. And, if you save all of the frames, not just the one SharpCap is stacking, you can go back and apply all the tricks that the traditional "deep space" imagers use. 

 

Alex


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#9 Jehujones

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Posted 02 December 2021 - 11:21 AM

"...Did you make sure that you can reach focus with your scope and camera? That is usually the biggest problem with Newts that are not designed for AP..."

Oh yeah, almost forgot. That was an issue with the 10" F4.5. Even though I already had a very low profile JMI focuser and a very low profile lens adapter, I was just a smidgen away from reaching focus. The image above was obtained by taking the adapter off the camera and holding the camera body against the back of the focuser racked all the way in. Since then I moved the primary forward just about 3/16" to reach focus. I was happy that I could still focus visually as well. When I got the new scope and I saw the long focuser, I thought for sure I would have to replace the focuser if I wanted to try imaging. Much to my surprise I was able to reach focus right out of the box. Perhaps the fact that the camera is mirrorless helps. It may not work with a DSLR but I have no desire to upgrade cameras right now. If I were to change cameras I would certainly get a dedicated imaging camera that I could use with a dedicated rig.

 

"...At 1225 focal length, you have a medium long scope. So, choose things that fit your field of view. To check out your Field of View, go to Telescopius.com, and use their telescope simulator with your scope and camera. Then, page through the possible targets.

 

So much for targets. 

 

As far as exposure, you have to remember that the big problem for you is field rotation. This shows the longer you run your exposures. SO, you want short exposures..."

Thank you so much Alex for all the great info. I think that the moon just fits in the frame, or maybe I'm thinking of the 10". I'll check out that link.

As for rotation, I don't mind a little bit messy stars. I figured that if I got any discernable images of galaxies I would severely crop the image anyways just to get rid of the coma. Yes, I know how beautiful galaxies look when surrounded by a field of stars but remember, this is just for me.

 

You guys are great, Thanks.



#10 bobzeq25

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Posted 02 December 2021 - 11:42 AM

Fellows, the OP is asking what is recomended to do with the current setup. Not, what should be with an ideal setup for beginners.

Visual astronomy.

 

Sorry, I don't support this philosophy.  You're asking someone else, who clearly knows little about this, to spend an inordinate amount of energy to little purpose.   After all, it's not your time.

 

As is often the case, experienced imagers are giving experienced imager advice about how they would struggle with bad equipment.  Which is not the same thing as getting into imaging.

 

I give advice about how people can get into imaging.  They can decide which course to follow.  Messing around trying to do DSO AP with a Dob, clearly one of the most futile things imaginable, especially for a raw beginner, or actually getting into imaging.

 

I know what advice I'm going to give. 

 

Speaking to Jehujones (only).  If you want to take pictures of the night sky, and have little budget for it, you'll do a lot better using a camera lens than the Dob.  People do that a _lot_ (I still do it sometimes) and make lovely images.  Here you can scroll through 41 pages of them.  Almost all use that $300-500 tracker.  You're trying to take a picture of a moving target that's very dim, using a camera with tiny .005mm pixels that can't cope with tracking errors.  So tracking the target extremely precisely  is everything.  A dob is not remotely the right tool for what you want to do.

 

https://www.astrobin...f5/?q=skyguider

 

As I said, unintuitive.

 

BUT.  My advice is aimed at people who want to progress in this hobby eventually.  If you just want to mess around and get something, fine.  Just don't spend a lot of time struggling, trying to get better at it.  It's not a good path for that.
 


Edited by bobzeq25, 02 December 2021 - 12:21 PM.

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#11 Jehujones

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Posted 02 December 2021 - 12:47 PM

Thanks Bob. I get that, and I totally understood the previous advice you were giving and I appreciate that too. Who knows what direction I may take in the future but I’m so glad I found this community and the wealth of knowledge found here.
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#12 imtl

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Posted 02 December 2021 - 02:51 PM

Thanks Bob. I get that, and I totally understood the previous advice you were giving and I appreciate that too. Who knows what direction I may take in the future but I’m so glad I found this community and the wealth of knowledge found here.

As you can see there are more opinions than telescopes on CN and all of us with good intentions to help out. I'm glad you joined in and hope you gain something from everyone and especially from your own experience and attepmts in imaging. The first baby steps could be difficult. Set your expectations accordingly and understand in advance the limitations of your setup.

 

Starting like that, with what you have, will be both realistic and enjoyable. Go into this with good spirit and have fun.


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#13 Jehujones

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Posted 02 December 2021 - 03:51 PM

"...all of us with good intentions to help out...Starting like that, with what you have, will be both realistic and enjoyable. Go into this with good spirit and have fun..."

Indeed, that is one of the great things I've noticed here. The willingness to really offer help. 



#14 Jehujones

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Posted 02 December 2021 - 04:13 PM

"... To check out your Field of View, go to Telescopius.com, and use their telescope simulator with your scope and camera..."

Thanks again Alex, that is really cool... (I hope I'm not breaking any rules by posting this image)

I'm sure the entire structure isn't bright enough for me to capture so I'm ok with field size.

 

Capture1.PNG



#15 Alex McConahay

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Posted 02 December 2021 - 05:38 PM

If you can capture any galaxy, M33 should be one to try for. It should be plenty bright. My buddy and I were looking at it the other night in my 15 inch Dob. Visually it acan be hard to see, and it is not the easiest to star hop to since there are not a lot of guide stars in the area. But......once you are there, you should have no problem.

 

Well, no more than all of us have in astroimaging!!! Ha Ha. 

Alex


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