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0.4 x to 0.5 x Reducer?

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#1 Rac19

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Posted 14 June 2021 - 04:53 AM

I have had the Starizona Night-owl on order since April 2020 with no indication yet as to when it might be shipped. As an interim measure, I have purchased a 2" GSO 0.5 x reducer but it has quite a bit of distortion around the edges.

 

Any suggestions as to another alternative would be welcome.

 

I think that some have tried two Celestron 0.63 reducers stacked together. I already own one, so that could be an option. I am not sure whether or not a spacer is required between them.


Edited by Rac19, 14 June 2021 - 07:29 AM.


#2 Rac19

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Posted 15 June 2021 - 05:51 AM

I see tear Starizona is now quoting deliveries in Q3, Q4 2021. That's for new orders. maybe my order (originally quoted as Q3, Q4 2020) might be shipped before thencrazy.gif, maybe not.



#3 Madratter

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Posted 15 June 2021 - 07:41 PM

All reducer/flatteners introduce distortion. The higher the reduction factor, the higher that distortion MUST be. A distortion-less reducer/flattener is not physically possible. That said, some are better than others and I'm not familiar with what you are using so don't know where it falls in the quality curve. Just be aware that all of them are going to make compromises.



#4 Tapio

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Posted 15 June 2021 - 07:59 PM

Some stack reducers for bigger reduction but that is more of EAA department where image quality is less important.
So as madratter told you get bigger distortions. Could work for tiny sensors.

#5 Rac19

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Posted 15 June 2021 - 09:44 PM

Thanks for both responses. When using the 0.5 x GSO, I generally use Region of Interest (ROI) to capture the image at the centre.



#6 Rac19

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Posted 18 June 2021 - 04:24 AM

I put the GSO 0.5 x reducer back in last night and captured this image of the Southern Pinwheel. It actually doesn't look too bad. I used plate solving to accurately centre it and a 1920 x 1200 pixel ROI so that the glass at the centre of the lens was used. Possibly my evolving knowledge of PixInsight helped. This is the first time that I have been able to clearly discern dust lanes for this Galaxy. If the NightOwl never materialises, perhaps I can live with the much cheaper GSO.

 

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  • SouthernPinwheel_20210617.jpeg


#7 Tapio

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Posted 18 June 2021 - 04:41 AM

Edge stars could look better but if you can live with that then that's all that matters.

#8 Rac19

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Posted 18 June 2021 - 05:02 AM

Edge stars could look better but if you can live with that then that's all that matters.

I can see that too and this is nowhere near the edge of the lens. I assume that the NightOwl would be an improvement. Maybe still not perfect right out the the edges but and improve the on (the cheaper) GSO. For now I have no choice, given the non-arrival of the NightOwl.

 

I have HyperStar for a wider FOV but galaxies such as the Southern Pinwheel are quite small at f/2.




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