Astrophotography - Deep Space Objects (DSO)

blackstar

Senior Member
If I may cut into this thread to ask a beginner's (dumb) questions (remotely DSO-related):
I started using Stellarium to prepare for my planned AP (Astrophotography) adventure. I set up my camera/lens view (Z8+MC105mm) in the program and started to play it around. Took some screenshots shown below:
VenusOriginal.jpg

VenusZOOM.jpg

The Ocular view of Venus
VenusOcular.jpg

Q1: The first pic shows the FOV (the red rectangle) of my camera/lens. Why is it positioned at an angle instead of horizontally?

Q2: Then I started to zoom in until Venus became large but still focused. Beyond that point, Venus image started to OOF. Can I assume the latest zoom that keeps the image sharp is when the actual image shot by my camera/lens is viewed at 100% scale?

Q3: I had hard time setting up my camera/lens view in Stellarium where I added two cameras and three lenses in the "sensor" and "telescope" sections (Tool icon at right-top) as I read online. There is no "set" or "save" button to finish the setting. Then I clicked the "sensor view" icon at the right-top, and it showed an FOV for the stock camera/telescope, even though I had highlighted my added camera/lens. After numerous trials, I thought all the stock cameras/sensors I do not use, so I removed them all and all left are my two added cameras. Then I started the camera view again and it showed as the first screenshot stating my camera/lens at the right-top corner. However, I didn't remove all stock telescopes and lenses but with one of my added lenses highlighted. More issues, from here on, there is no way to change either my cameras or lenses for the special view (unless I remove one of my cameras and/or two of my three added lenses). How do you effectively set up your own camera/lens view in Stellarium without all these nuisances? Thanks for your help.
 

BF Hammer

Senior Member
Q1 answer: That is framed for a telescope/camera mounted on an equitorial mount with no ball-head. This is the framing I require on my setup. But if you are using a star-tracker with a ball-head attached for the camera, then you also have independent adjustment to square to the horizon if you desire.

Q2??: I don't follow your question here. Looking at your planned lens on the screenshot, 105mm is not much telephoto, even for Venus. Think 400mm or better. Your Z8 will have more pixel density than any camera I have used but it will benefit with all the optical zoom you can get. Don't worry about needing f/2.8 because you can comfortably use f/6.3 to f/8 on planets out to Saturn.

Q3: My biggest thing I had to research was the sensor size of my cameras. I do not remember having to do a save when I set up multiple telescopes in Stellarium. Basically each lens would have to be a separate telescope. I just have not done it for many months so I can't comment more.



Edit: Circling back to the first question, just uncheck Equitorial Mount on the setup of the telescope.
Screenshot 2024-10-07 201817.png


And no it is not necessary to "save". You just click the Add button and edit the fields.
 
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blackstar

Senior Member
Thanks, BF.
I see after unchecking the H-flip, V-flip, and EQ mount, a horizontal FOV was shown. To clarify my Q2: I reckon that the first view when Stellarium is open shows the scene that is eye-viewed from my place (on Earth). When the sensor frame is on, the scene becomes (zoomed in) camera sensor-viewed with the sensor frame rectangle at the center. Is what you see covered in the rectangle what you see in the VF or LV of your camera? If so, what is the zoom out % the rectangle size is set from the image size the camera shoots? (e.g., open a regular photo image in an editor like Gimp. It will show a zoom-out 25% or 50% image. Then you can zoom in to 100%) Certainly, the frame rectangle is not 100% of the image size. How much do we zoom in on the rectangle to view the 100% image but not bigger?

I see your Stellarium is a different version of mine (24.3 Qt6 for Mac). Maybe Windows? I found my version is somehow crippled. You can see from my screenshots that the "tool" icon at the right top is cut off a little. Also see from your post the "sensor frame" dialog shows some << and >> buttons or clickable signs that do not exist in my version. I suspect the << and >> are for changing camera or lens (telescope)... Is that why I can't change the camera or lens in my version? Bummer!
 

BF Hammer

Senior Member
Stellarium is a Linux project and ported to Windows and Mac. Kind of surprised your version would be crippled.

When the sensor specs are entered right for your camera, the telescope selected shows as the box, which is the estimated field of view. It is very close based on past projects. I never have bothered with the ocular view because the FOV box is going to approximate my image capture. So I think that answers it. I set my Sigma lens to be 600mm and I set the diameter to the front element opening. You have to Google for the Z8 sensor specs (XY resolution, pixel size, density) and that all calculates the image capture box.

Maybe there is some keyboard way to cycle the telescope? Maybe click it with mouse and use the touch gestures to scroll? I only know enough Mac to install printer drivers and fix print configuration problems.
 

blackstar

Senior Member
I tried many ways to change camera (sensor) and telescope (lens) without success. I am surprised because I am using a pretty new Mac system and have installed the latest version of Stellarium. The Stellarium is still crippled! What can you say?
 

blackstar

Senior Member
I hope to refresh this thread a little. Need verification and comments on my observation with Stellarium. I took some screenshots shown below and tried to figure out if the application of camera view on Stellarium matches the live field view without doing it on the field.

First SS (screenshot) shows the moon scene from SL (Stellarium). I assume it's the eye view from my place (if wrong, please point out).
Moon-eye.jpg


2nd SS shows the camera FOV (field of view) of the moon scene (z8+600mm) - a zoom-in image very close to the live view of the camera.
Moon-z8-600.jpg


3rd SS shows the North American Nebula (NAN) view from SL (again, assume bare eye-view)
NorthAmericaNebula-eye.jpg


4th SS shows camera FOV z8+600mm
NAN-z8-600.jpg


5th SS shows camera FOV z8+105mm
NAN-z8-105.jpg


6th SS shows camera FOV z8+20mm
NAN-z8-20.jpg


For z6ii, FOVs with different lenses are all the same as z8, the resolution difference does not affect FOV in SL. From all the observations above, I suspect that from the three lenses I own (add 24-120mm, a zoom lens), the 600mm may not be adequate for imaging DSO (if the NAN counts) due to its narrow field as it can't even cover the whole NAN. Also, it could cause difficulty to point to the scene. The 105mm MC has a wider view field, it can even cover another nearby nebula. I presume for a real 100% image of 105mm, the scene will be much larger than from the FOV and can be useful. The 20mm is too wide to work on DSO imaging. However, certainly, there are better lenses for AP like 200mm, 300mm, and even 400mm. But I don't own either. :(

I need your verification of my observations with the SL and comments on the lens usage for AP. Thanks
 

BF Hammer

Senior Member
Without checking on Stellariun first, the FOV all looks about right to me. The physical dimensions of the sensor is what factors into the FOV so 2 full-frame sensors with the same lens create the same FOV. But the higher res sensor will have more detail recorded.

From practical experience, 600mm or higher is good for Orion nebula, but wider if you want the surrounding nebulas included. I have had some interesting composition of the entire constellation of Orion with a Tamron 90mm. Andromeda Galaxy frames up nicely at 400mm.

20mm is good for a Milky Way landscape image, but even wider is normally desired. It is why I was good with selling my Sigma 20mm f/1.4 after getting my 15mm f/2.8. In addition to the Zeiss gives a spectacular flat field image.

My current favorite DSO lens is a 70-200mm f/2.8. When I bought it i was thinking more about filling a gap between a 24-120mm and my 150-600mm, wondering if I really needed it. Turns out I do need the lens.
 
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