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Dobsonian Astro Photography Beginning

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#1 patindaytona

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Posted 14 September 2019 - 06:10 PM

Completely new to this. What's the best way to do it. I have very limited funds.

I've been reading alot on PIPP, Stackkert, and Registak, but I will just have to go for it and not know precisely what every setting is in those programs.

When you video and drift, are you turning off the recording each time you bring the scope back to let it drift again?

PIPP will join all those videos in registration? What is you have some videos by accident where it's nothing but black in the video, or even "half" the planet went past the eye piece? It'll still register the good frames?

 

I was looking at the inexpensive adapter for the Canon DSLR.   Not sure if i'll have the focal length. I see some have to use a barlow to reach it.

 

What if i were to let drift, some region of the moon (not the entire diameter). Of course, some will be out of alignment. What would happen when using resistak to something like that?



#2 Jim Waters

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Posted 14 September 2019 - 07:01 PM

Some questions...

 

What's the DOB?

Does the DOB have an ALT/AZ mount?

Will you be mounting the DOB on an EQ mount?

What's the Canon DSLR?

 

You will probably find the DOB does not have enough Rack-In focus and you will not be able to focus the camera.


Edited by Jim Waters, 14 September 2019 - 07:02 PM.


#3 Maxtrixbass

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Posted 14 September 2019 - 07:08 PM

I'm sure many will chime in, but the short answer is dobsonians aren't really designed for astrophotography. They really are more visual setups. That doesn't mean its impossible, but there are some challenges primarily because of the mount. My experience with planetary stacking programs is that they still like to have the target fairly steady in the frame..some "bounce around" is OK, but stacking a target that drifts across the whole frame would be problematic.

 

The second challenge as Jim posted is that newtonians, which I assume your dob is, are set up to focus for eyepieces, but DSLRs would require more inward travel on the focuser. That's not too hard to change really, but anything past a single frame of the Moon would still be difficult.

 

Most people doing planetary AP have their optics on a equatorial mount usually with some sort of motor. With more deep sky imaging the demands on the mount become much higher still.

 

I have a nice pretty big dobsonian, do a fair amount of AP with other setups, and just couldn't resist the urge to hook up my camera to the dobsonian. I gave up on the idea since it started to feel like I was trying to put a square peg into the round hole, so again, not impossible, but just not designed with that in mind.


Edited by Maxtrixbass, 14 September 2019 - 07:14 PM.

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#4 zxx

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Posted 14 September 2019 - 07:22 PM

I made an EQ platform for my Z12, with out it, can be vary difficult with a dob depending on the FL.


Edited by zxx, 14 September 2019 - 07:27 PM.


#5 jgraham

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Posted 14 September 2019 - 07:29 PM

I did a fair amount of lunar and planetary imaging with a Canon 600D and a Lightbridge 16. I had to add a 2" 2x Barlow to reach the focus. T'was a fair challenge and a lot of fun!
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#6 zxx

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Posted 14 September 2019 - 07:39 PM

I raised the mirror in my Z12 to reach focus with my K50

 

300mm f5~1.jpg


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#7 patindaytona

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Posted 14 September 2019 - 08:06 PM

Some questions...

 

What's the DOB?

Does the DOB have an ALT/AZ mount?

Will you be mounting the DOB on an EQ mount?

What's the Canon DSLR?

 

You will probably find the DOB does not have enough Rack-In focus and you will not be able to focus the camera.

XT10i dob.  Canon 5D Mark II

Just the regular base (Skyquest Orion).  I suppose that's ALT/AZ


Edited by patindaytona, 14 September 2019 - 08:08 PM.


#8 patindaytona

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Posted 14 September 2019 - 08:11 PM

I realize a dobsonian is limited to just a few of the brightest objects.

What about the moon or the sun.....would you stack them from a video, or are those better as still frames?

Planets such as Jupiter or Venus....From what I've ready you're supposed to set the video on pause after it's out of the eye piece. Then resume again.



#9 APshooter

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Posted 14 September 2019 - 11:20 PM

Moon is better stacked from video, although a still will do in a pinch.  If you can track the planets manually, you can try recording video of them to stack in AS2!



#10 Maxtrixbass

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Posted 15 September 2019 - 12:22 PM

Moon is better stacked from video, although a still will do in a pinch.  If you can track the planets manually, you can try recording video of them to stack in AS2!

I think the main concern is the ability to track at all with a dob mount. That would mean manually pushing the thing on two axis..The XT10i I believe has a "locator assist" kind of goto (tells you where to move to), but no motors or slow motion controls (like an equatorial mount might have). This would make anything time based, like video or long exposures, really difficult. Most people using video are doing so on motorized equatorial mounts.

 

It could be thought of it like a BIG camera lens on a tripod taking images of slow moving targets  (in this case the Earth rotating) , then single frame shots of some bright targets like the moon or maybe planets are feasible. The full frame 5D would give some nice stills if the exposure was short enough...maybe even snapping a dozen frames, picking the best, and aligning them manually in Photoshop or the like.


Edited by Maxtrixbass, 15 September 2019 - 12:32 PM.

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#11 Jeff Lee

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Posted 15 September 2019 - 12:49 PM

Visit the EAA forum, someone is doing EAA with a Dob.


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#12 bobzeq25

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Posted 15 September 2019 - 01:14 PM

Basics.

 

The Dob can do lunar/planetary imaging.

 

DSOs with a Dob are strictly an expert deal, and it takes a _lot_ of money.

 

This forum is mostly for DSOs, the Solar System Imaging forum can help you better with lunar/planetary.

 

If you want to try DSOs, the best way for you to start would be with a camera and a lens.  The Dob just makes things very, very hard.  This book explains how.

 

http://www.astropix....bgda/index.html


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#13 Stephen Kennedy

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Posted 16 September 2019 - 05:12 AM

I would be very cautious about putting the Sun in the FOV of a 10" (250 mm) mirror without very robust filtering.  Otherwise, it will cause loss of vision if looking through an eyepiece and will destroy the sensors in a camera in seconds.  When my 210 mm Newtonian is pointed at the Sun, a sheet of paper at the focal point catches on fire almost instantly.


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#14 patindaytona

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Posted 16 September 2019 - 09:39 AM

Visit the EAA forum, someone is doing EAA with a Dob.

New here..what's the EAA?



#15 Jeff Lee

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Posted 16 September 2019 - 09:51 AM

New here..what's the EAA?

https://www.cloudyni...ost-processing/

 

Electronically Assisted Astronomy


Edited by Jeff Lee, 16 September 2019 - 09:51 AM.


#16 patindaytona

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Posted 16 September 2019 - 10:05 AM

https://www.cloudyni...ost-processing/

 

Electronically Assisted Astronomy

thanks



#17 bobzeq25

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Posted 16 September 2019 - 10:17 AM

https://www.cloudyni...ost-processing/

 

Electronically Assisted Astronomy

A bit of further explanation.  EAA uses fairly short exposures and little or no processing to produce images.  It's intermediate in quality between visual astronomy and traditional imaging.

 

For you, the advantage is that EAA doesn't require anywhere near as good a mount as traditional astrophotography.  There's a separate EAA forum here, they could answer questions about doing EAA with a Dob.



#18 Stephen Kennedy

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Posted 17 September 2019 - 03:54 AM

I can certainly Say that EAA was what motivated me to start taking photos of astronomical objects again five years ago.  I had done astro-photography in the 1980s using film but eventually gave up on it because of the nearly insurmountable difficulties in getting decent images with film with its 1% quantum efficiency (QE),  I still did visual astronomy but increasing light pollution was really frustrating me in observing DSOs.  When I got my first DSLR as a Christmas present five years ago I decided to attach it to my telescope and see what would happen.  I aimed it M42 and took a 90" exposure and was absolutely astounded at the image that appeared on the camera's screen.  It was far better than any images I had ever taken with film.  I used the setting circles to go to M1 that is not visible in an eyepiece because of LP and took a 120" exposure and there it was.  Except for the camera the equipment I was using and still use dated from the 1980s and there was no way to guide my mount, so  basically I practiced EAA until I learned that I could take 60"-120" unguided exposure and stack them.  My Pentax MS-5 GEM has a PE of <+- 2" so this was quite doeable.  I gradually evolved from just using  single images to just be able to see DSOs to taking multiple subs and using DSS to create my pretty rudimentary astrophotos.  I am still somewhat limited using a 32 year old GEM and  OTA but have managed to get some interesting images.   


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#19 patindaytona

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Posted 17 September 2019 - 07:32 AM

I can certainly Say that EAA was what motivated me to start taking photos of astronomical objects again five years ago.  I had done astro-photography in the 1980s using film but eventually gave up on it because of the nearly insurmountable difficulties in getting decent images with film with its 1% quantum efficiency (QE),  I still did visual astronomy but increasing light pollution was really frustrating me in observing DSOs.  When I got my first DSLR as a Christmas present five years ago I decided to attach it to my telescope and see what would happen.  I aimed it M42 and took a 90" exposure and was absolutely astounded at the image that appeared on the camera's screen.  It was far better than any images I had ever taken with film.  I used the setting circles to go to M1 that is not visible in an eyepiece because of LP and took a 120" exposure and there it was.  Except for the camera the equipment I was using and still use dated from the 1980s and there was no way to guide my mount, so  basically I practiced EAA until I learned that I could take 60"-120" unguided exposure and stack them.  My Pentax MS-5 GEM has a PE of <+- 2" so this was quite doeable.  I gradually evolved from just using  single images to just be able to see DSOs to taking multiple subs and using DSS to create my pretty rudimentary astrophotos.  I am still somewhat limited using a 32 year old GEM and  OTA but have managed to get some interesting images.   

I have been deeply involved with photography past 45 years myself, and never got to where i would actually use my older film based camera to take astrophotos. So, luckily, I have a DSLR to start with. My sister gave me her late husband's Canon 5D Mark II, so it should really do well for this.

When you are taking the 120" long exposures you mention, are you refering to a video?

If you are, are you doing a single video and just putting it on pause each time the object drifts out of view, then resuming it again and again?



#20 bobzeq25

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Posted 17 September 2019 - 03:57 PM

I have been deeply involved with photography past 45 years myself, and never got to where i would actually use my older film based camera to take astrophotos. So, luckily, I have a DSLR to start with. My sister gave me her late husband's Canon 5D Mark II, so it should really do well for this.

When you are taking the 120" long exposures you mention, are you refering to a video?

If you are, are you doing a single video and just putting it on pause each time the object drifts out of view, then resuming it again and again?

It's a single 120" exposure.  Depending on circumstances DSO imagers can sometimes use 30 minute exposures.

 

DSO imagers don't use video much, if at all.  The reason is DSOs, even so called "bright" DSOs, are much dimmer than planets.  The miracle of DSO imaging is that the pixels can accumulate very low levels of light over a long time.  But that only works if you can keep the telescope _extremely_ precisely pointed at the moving target.  An accuracy of less than 1/1000 of an inch is needed.  That requires an expensive mount, and autoguiding.

 

So, not only does the target not drift out of the field, it really doesn't move at all.

 

The mount, not the scope or the camera, is the most important part of a DSO imaging setup.  Scroll down to the picture of the expert author of this book.  That setup ($500 refractor on a $1200 mount) may look silly to you.  It's not.

 

DSO imaging is a complcated, unique, and often unintuitive deal.

 

http://www.astropix....bgda/index.html


Edited by bobzeq25, 17 September 2019 - 03:59 PM.


#21 zxx

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Posted 17 September 2019 - 08:28 PM

I have been deeply involved with photography past 45 years myself, and never got to where i would actually use my older film based camera to take astrophotos. So, luckily, I have a DSLR to start with. My sister gave me her late husband's Canon 5D Mark II, so it should really do well for this.

When you are taking the 120" long exposures you mention, are you refering to a video?

If you are, are you doing a single video and just putting it on pause each time the object drifts out of view, then resuming it again and again?

I did a little video planet imaging with my Z12 dob. It was a challenge with the small sensor on the ZWOASI120MC. It was tough to find the planet with a 3x barlow at 4500 FL and had no luck with trying to get video before it drifts out. never tried it with a DSLR with a larger sensor. I believe you want your video to be under two minuets or less or the planets rotation will affect the image. I built a EQ platform and was able to get this without pulling my hair out lol.....

 

Capture sat.PNG


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#22 Stephen Kennedy

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Posted 18 September 2019 - 12:03 AM

I have been deeply involved with photography past 45 years myself, and never got to where i would actually use my older film based camera to take astrophotos. So, luckily, I have a DSLR to start with. My sister gave me her late husband's Canon 5D Mark II, so it should really do well for this.

When you are taking the 120" long exposures you mention, are you refering to a video?

If you are, are you doing a single video and just putting it on pause each time the object drifts out of view, then resuming it again and again?

It is a single exposure of 120".  As Bob said above, videos of DSOs are rarely taken for the reasons he mentioned.  Instead we take multiple images called subs of the DSO that with a good mount does not move in the FOV and then use a computer program such as Deep Sky Stacker (DSS) to add the images up to create one image of the object.  It can then be processed further with different software.  My mount is 32 years old and does not have encoders and can not be autoguided.  No mount without encoders can take a 30 minute sub,  If I really worked on polar alignment I could probably get good 180" subs but that is about the best you can hope for from an unguided mount and 1,623 mm of focal length without absolute encoders. 

 

I have taken videos of about 30" in duration  of planets and the Moon and use a program called Registaxx.to stack all of the individual frames into one final image that can then be further   processed.  This technique allows for a spectacular improvement in image quality compared to single exposure images of the Moon and planets. 


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#23 patindaytona

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Posted 18 September 2019 - 07:45 AM

It is a single exposure of 120".  As Bob said above, videos of DSOs are rarely taken for the reasons he mentioned.  Instead we take multiple images called subs of the DSO that with a good mount does not move in the FOV and then use a computer program such as Deep Sky Stacker (DSS) to add the images up to create one image of the object.  It can then be processed further with different software.  My mount is 32 years old and does not have encoders and can not be autoguided.  No mount without encoders can take a 30 minute sub,  If I really worked on polar alignment I could probably get good 180" subs but that is about the best you can hope for from an unguided mount and 1,623 mm of focal length without absolute encoders. 

 

I have taken videos of about 30" in duration  of planets and the Moon and use a program called Registaxx.to stack all of the individual frames into one final image that can then be further   processed.  This technique allows for a spectacular improvement in image quality compared to single exposure images of the Moon and planets. 

Stephen, when i said are you pausing the video, i mean, do you hit the pause just as the planet goes out of view, then return the planet so it drifts back into view, resuming the video, so that it amounts to 30" total, all in a single video? Their is a progam call PIPP which joins videos together.



#24 charotarguy

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Posted 18 September 2019 - 01:25 PM

Have done planetary imaging using a 10" Orion XT quite a few years back. What I was told by an experienced imager who also used to image planets through a non tracked dob is to get the viewfinder aligned finely, angle the sensor of the camera (dslr or a webcam type camera) such a way that the planet drifts maximum distance on the sensor, that travel of the planet would be diagonally on the sensor, once the planet gets closer to the edge of the sensor on the far side, pause the video acquisition and align the scope again so the planet now is on the other side (starting side) of the sensor, do this over and over again. Key here is to align your viewfinder very very fine with the scope, took me month and a half and many hair pulling sessions to get the planet on the sensor of my camera, but once I got the hang of this it slowly became easier over the time. I've since moved on to a tracked dob and a sct riding on a eq mount which had made life so easy, but the time I spend struggling getting something is the best time I've had in terms of capturing a planet. Here are some examples.

Attached Thumbnails

  • 2015-04-13-0143_1-RGB-30_g4_ap28_Drizzle15-rg-ps.jpg
  • 2015-04-05-0126_7-RGB-3_pipp_g4_ap16_Drizzle15-rg-ps.jpg
  • 2015-05-26-0453_3-RGB-12_AS_p75_g4_ap13_Drizzle15_conv-rg.jpg

Edited by charotarguy, 18 September 2019 - 01:28 PM.

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#25 patindaytona

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Posted 18 September 2019 - 01:56 PM

Have done planetary imaging using a 10" Orion XT quite a few years back. What I was told by an experienced imager who also used to image planets through a non tracked dob is to get the viewfinder aligned finely, angle the sensor of the camera (dslr or a webcam type camera) such a way that the planet drifts maximum distance on the sensor, that travel of the planet would be diagonally on the sensor, once the planet gets closer to the edge of the sensor on the far side, pause the video acquisition and align the scope again so the planet now is on the other side (starting side) of the sensor, do this over and over again. Key here is to align your viewfinder very very fine with the scope, took me month and a half and many hair pulling sessions to get the planet on the sensor of my camera, but once I got the hang of this it slowly became easier over the time. I've since moved on to a tracked dob and a sct riding on a eq mount which had made life so easy, but the time I spend struggling getting something is the best time I've had in terms of capturing a planet. Here are some examples.

I would love to get some images like these!

When you say to align the viewfinder very very fine, not sure how to do this. Once the camera is attached with the adapter, their isn't much else i can do to be sure it's aligned any finer.




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