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Will the Starizona .65 reducer for the Esprit100 work in this case?

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#1 Yomamma

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Posted 05 October 2024 - 02:56 PM

I have been using my ASI2600 with my Esprit100 and the one thing that has given me a problem is that the 2600 has too large a sensor for many of the objects that I imaged.  Many of these objects appear very small in the center of the image and I have to crop like crazy to get them to a point that I can work on them.  At this point they have also lost a bit of clarity and are becoming fuzzy in areas.

 

I have an ASI585 on the way to use for these smaller objects.  It has a sensor size of only 11.2 x 6.3 and has a smaller pixel size so I am hoping to get better resolution and larger objects to work with.

 

The Starizona .65 reducer has an image circle of around ~30mm and I have heard about the issues with this reducer around the edges.

 

With a camera sensor width of only 11mm and the reducer having a 30mm circle it would seem that these edge issues would not be a problem for me under this setup.  I would have over 9mm of empty space on the longest sides and much more on the short sides. I am not an expert on this so I thought I would ask to see if this is correct or I am missing something. I think I should be able to use under these circumstances.

 

Thanks for your help.

 



#2 Spaceman 56

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Posted 05 October 2024 - 03:29 PM

Yomamma I an not an expert but will say what I have experienced.

 

For smaller targets, like most Galaxies, the most important thing you need is Focal length. nothing beats focal length.

 

I have some premium optics, and I shoot from Bortle 1 so I can say this with confidence.  smile.gif

 

shooting with a 530mm Takahashi FSQ and even with 10 hours of very good data small target results are not spectacular.

 

Tweezers Galaxy. NGC4945
 
shooting with a 1484mm RC scope I get shots like this, with only 2 hours of so of Data.
 
Pinwheel Galaxy with an RC10.
 
now if you combine a Long Focal length telescope with a camera with a smaller sensor, and perhaps smaller pixels,  I believe you will get the best results.  waytogo.gif
 
personally myself I just bought a 533 ZWO to put on my RC10 inch, as the wide FOV is not always required, and the 533 quality should be similar to the 2600 I own.
 
having said that the 533 is 14 bitt and the 2600MC is 16 bitt, so there is a loss in that, but the pixel size is identical, so hopefully much of a muchness.
 
as for the Focal reducer idea I dont think that will help at all. the Esprit is not a long focal length OTA and a reducer will just shorten it up and make it worse.
 
Experts will know more. Spaceman
 
 

 



#3 smiller

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Posted 05 October 2024 - 03:47 PM

With respect to cameras, the sensor size has no impact on the resolution and clarity of your image capture.  That is driven by the pixel size.   Sure you may crop the image more with a larger sensor, but the end results is the same regardless of the size of the sensor if the pixels are all the same size.

 

If you want to capture targets with higher resolution there are several choices:

 

1) Use a smaller pixel sized camera.

2) Use a longer focal length telescope

3) Increase the focal length of you telescope.

 

Eventually you will hit the limit of either atmospheric seeing or the optical limits of your telescope or your guiding accuracy.  I expect with the ASI2600MC and the Esprit 100, you aren’t at the limits yet.

 

Secondly, I’m not sure what the reducer has to do with this but it appears to be your main question?   I’ll let others that have that reducer speak as to the quality but in general the image circle is compared to the diagonal measure of your sensor and if your sensor fits within the image circle you are good to go if you are using the correct reducer for your type of telescope. 


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#4 sn2006gy

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Posted 05 October 2024 - 04:03 PM

To answer the reducer question, I found Esprits didn't like the starizona reducers on APS-C sized sensors so you'd still be cropping a lot for stars on corners that lose their shapes.




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