Double image in reflector telescope

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Discussion Overview

The discussion revolves around issues experienced with a reflector telescope, specifically the occurrence of double images. Participants explore potential causes such as collimation problems, mirror quality, and focusing techniques, while also comparing experiences with refractor telescopes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes experiencing double images with their new reflector telescope and questions whether it is a collimation issue.
  • Another suggests that the problem might arise from focusing on objects that are too close to the telescope, asking for the distance to the object and the telescope's focal length.
  • A participant provides the focal length of their telescope (1400mm) and shares an image of the Moon, indicating the same double image issue.
  • Some participants recommend checking the alignment of the telescope and provide links to resources for collimation.
  • Concerns are raised about the quality of the mirror, with one participant expressing doubt about their mirror's performance compared to their refractor.
  • There is a suggestion that the double image issue may be resolved by focusing correctly and adjusting the camera setup.
  • Participants discuss the effectiveness of using different cameras for astrophotography, with one recommending a webcam for better results.
  • Another participant shares their success in improving image quality by adjusting focus and using a specific eyepiece setup.
  • Questions arise regarding the setup of tracking for a GPS telescope, with a request for guidance on alignment procedures.

Areas of Agreement / Disagreement

Participants express a range of views regarding the causes of the double image issue, with no consensus reached on a single definitive solution. Some agree on the importance of collimation, while others focus on camera quality and focusing techniques.

Contextual Notes

Participants mention various assumptions about mirror quality and telescope alignment without resolving these points. The discussion includes references to specific techniques and resources for collimation and astrophotography, but these are not universally accepted as solutions.

Who May Find This Useful

Individuals interested in astrophotography, telescope setup, and troubleshooting issues with reflector telescopes may find this discussion relevant.

kolleamm
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Complete reflector novice here. Just got a reflector (using refractor before). I had no problems doing astrophotography with my refractor however with the reflector I get double images.

Why is this so? Is this a collmination problem? It's not the camera because there's double images when I look through myself.

Thanks in advance
 

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Astronomy news on Phys.org
Just a guess but, it looks like you're trying to focus on something that is too close to your telescope. How far away is the object and what is the focal length of the telescope?
 
It has a 1400mm focal length. Here is also a picture of the Moon which appears to have the same problem. The tree is just across a small parking lot.
 

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Then you may need to http://www.skyandtelescope.com/astronomy-resources/how-to-align-your-Newtonian-reflector-telescope/.
 
Borg is correct.

The moon definitely doesn't have the same problem. It may not be quite perfectly in focus, but it is close.
 
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Is it possible I have a bad quality mirror? My refractor had half the aperture and gave me way better detail. Although yeah it could be the alignment.
 
kolleamm said:
Is it possible I have a bad quality mirror? My refractor had half the aperture and gave me way better detail. Although yeah it could be the alignment.
Based on the pictures you posted, I find it very unlikely that you have a bad quality mirror. But you may want to look into a "star test collimation".
 
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kolleamm said:
My refractor had half the aperture and gave me way better detail.
Here's a link on http://www.twcac.org/onlinehorizon/collimation.htm of the telescope with some good graphics.
Have you ever wondered why your reflecting telescope didn’t perform as well as a refractor of even half the aperture? Do you think that perhaps the main mirror in your telescope doesn’t quite measure up to others of equal size that you’ve looked through? Do you always seem to be blaming the seeing conditions for poor images even when someone right next to you thinks the seeing is pretty good? Chances are that the only thing wrong with your reflecting telescope is that it needs to be collimated.
 
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Thanks guys, I'm going to change the cam first too and see if that helps. I was using my iphone (8 MP) but this cam is only 3MP, so I'm going to print out a support and see what happens, and align the mirrors too.
 
  • #10
Does it look better with your eye? I wouldn't trust an iPhone with this task. FYI, none of the pictures on my website were taken at more than 2mp.
 
  • #11
russ_watters said:
Does it look better with your eye? I wouldn't trust an iPhone with this task. FYI, none of the pictures on my website were taken at more than 2mp.
Wow your images are very impressive! Especially being able to see some color on Europa.
 
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  • #12
kolleamm said:
Wow your images are very impressive! Especially being able to see some color on Europa.
Thanks! My recommendation if you're on a budget is to get a decent webcam, remove the lens and attach it without an eyepiece to the end of the telescope. That's called "prime focus photography". Then take uncompressed videos and use stacking software like Registax (free) to process it. That's how you get the ultra-clear photos of the moon and defeat atmospheric distortion.
 
  • #13
russ_watters said:
Thanks! My recommendation if you're on a budget is to get a decent webcam, remove the lens and attach it without an eyepiece to the end of the telescope. That's called "prime focus photography". Then take uncompressed videos and use stacking software like Registax (free) to process it. That's how you get the ultra-clear photos of the moon and defeat atmospheric distortion.

Sweet. I managed to hopefully fix the double image problem by just focusing the telescope right. I took off the lens on the cam that came with the telescope and attached it to a 10mm eyepiece, the magnification looks way better.

Would you have any advice on how to set up tracking for a GPS telescope. I haven't found any good tutorials. I did the Moon alignment test and it didn't work. I see a sign on my telescope that says south, so am I supposed to point the telescope south before the test? Thanks in advance!
 
  • #14
All telescopes are different: what is the make/model?
 

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