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Old 24-02-2013, 07:31 PM
Vasya Pupkin (Pupkin)
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First images of bare CMOS astrophotography

Yesterday was very successful for me. For 3 days I have been trying to take a photo of M42 (senescent object). My first scope photo of it was made in September, but it way a photo by compact camera and with too many lenses (7 from my scope (so many, what for?) and #? from camera). Now I tried with bare CMOS and only 3 lenses in scope (I unscrewed some lenses). Unfortunately I live in a large city and I don't have an equatorial mount (I am going to buy it in April).
So, the results:
M42, 3.2sec*10. At last, my dream becomes reality: its “horns” appeared. 10m stars are available.
M45, 2sec*10. 10m stars are available.
“Pole zone” 20sec*6. This needs comments. Bright star is Polaris. As this region isn’t available for you and it hasn’t any DSOs, I comment only one thing: one star 13m is marked for example. This image is a model: I took it photo to see, what I’ll have with mount. Circles are the bad effect from subtracting the light pollution parasitic light.

Canon EOS 1100D, ISO6400. All images were processed in Photoshop.
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Old 24-02-2013, 09:11 PM
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Quote:
Originally Posted by Vasya Pupkin View Post
....with too many lenses (7 from my scope (so many, what for?) ...
Vasya,
you can't remove lenses from optical system just like that - they are there for a reason.
This is why the stars look triangular.. very bad case of coma, those lenses you removed were there to correct this problem.

BTW, which telescope is that?

EDIT:
OK, I see.. it is LZOS 60mm.
Those lenses yopu removed are at the back end (eyepiece)?
So you took this photo in prime focus? Should be better - I used to have that scope long time ago and the objective optics was pretty good.
How about focus and alignment of the whole system?
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Old 24-02-2013, 11:54 PM
Vasya Pupkin (Pupkin)
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Lenses

I had to remove them, because before it I couldn't work with bare CMOS at all: if even I managed to focus, the crop as awful (disability of astrophotography, only terresial, but fuzzy). Now, after removing ocular (2 lenses), one from former zoom and one, that I don't know, I managed to focus with little crop (you see circular board of image), that is what I want (in this form, with circular board I had been working when I used compact camera).
About coma, it exists only far from the centre of image, and it isn't caused by removing lenses, it exists before. By the way, I have not one experiment on removing lenses, I have seen another effects, more scaring.
In some time I'll by better scope, with less lenses! Normal scope (not mine, I have spyglass, not scope) is intended for sky observations and astrophotography. But me, I am trying to milk a bull.

On picture: red lenses are removed, green - not. Zoom lenses were movable.
But great thanks for your comment.
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Old 25-02-2013, 05:28 AM
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I see...
I also see you are an adventurous person , and you do not hesitate to take things in your hands Just like me! This was the path I went through long time ago, also with LZOS Turist (it wasn't zoom, just terrestrial eyepiece), and it was with Practica film camera.
Well, if you do not need that scope for terrestrial, and you can't wait for a "real" telescope, it would be be better if you removed the zoom and ocular completely..
Then, try do determine the focal length (by observing the image of the Sun or Moon on a piece of paper and measuring the distance between the objective and that paper when image is sharp). It will be ~400mm or close.
Then,you can buy on ebay or rugift.com the M42-EOS adapter.. and with the help of a metal worker (turner) you can mount it on the telescope tube by making a M42x1 thread on it.
Cut the tube of your telescope such that the focal point falls exactly 45mm further than the flange, but allow for some adjustment (thread needs to be a bit longer, for adjusting a focus).
Or, even better, turner can make the completely new tube for your objective lens, with M42x1 thread (for EOS adapter) on the other end.
This setup will perform much better than what you have now.
Good luck!
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Old 25-02-2013, 08:14 AM
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Пошлите мне сообщение, с вашим домашним адресом. Я имею подарок для Вас. ilyushin.letchik@gmail.com
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