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Cjg

Vaonis the Stellina Telescope is released on 31st March

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43 minutes ago, Pondus said:

On their  "captured by Stellina" image gallery esp.  Orion Nebula, theres clearly diffraction spikes on the stars?

Yes, they're clearly there on the M81/M82 image too.  The stars in both those images look quite unpleasant shapes in places too, and in a way that for some not entirely quantifiable reason makes me think it's an optical problem rather than drift.

I guess the main diffraction spikes could be down to something intruding into the light path of the refractor (lens spacers perhaps?) but there are quite a few smaller ones too.  No idea what might have caused them.

I'm not sure however that these are issues that will be a concern to the target market.

James

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21 minutes ago, JamesF said:

I'm not sure however that these are issues that will be a concern to the target market.

Unless these images arent from the Stellina at all ...   

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That is of course a possibility, but it's not unknown for refractors to have diffraction spikes and you'd probably even find some examples on this forum.  To be fair I am struggling to think what would cause them to be quite so strong with a refractor.  I'm sure you could always ask them to explain the cause :D

James

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The stars on both the M81-M82 and M42 image show signs of guiding or tracking errors, I would think. The M81-M82 image shows no sign of diffraction spikes. Maybe they added some in post-processing of the M42 image? Some people like them. The camera seems to have roughly the resolution of an ASI178MC, i.e. 6 Mpixel, which isn't bad.  Istill think I get better results with an 80 mm scope both on M42 and the moon

M42USM3expcropsat2curves.thumb.jpg.13932e16535b78ba0a86f3bc04665276.jpgmoon01122017mosaic.thumb.jpg.5aa40194ee9d75946162a076178d9f68.jpgMoon_212329_lapl4_ap1244LR1000.thumb.jpg.67599e11f6b229b988f102200f5e6c6b.jpg

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Diffraction spikes added in software generally look "too perfect" when I've seen them.  These don't look like that to me.  I'm sure I saw them in the M81/82 image as well.  I'll have another look.

James

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Just now, JamesF said:

Diffraction spikes added in software generally look "too perfect" when I've seen them.  These don't look like that to me.  I'm sure I saw them in the M81/82 image as well.  I'll have another look.

James

Maybe I didn't look properly. BTW, the M42 image I posted was my first attempt with an autoguider on an EQ3-2. I think it shows better stars than the images posted on the Vaonis site

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6 minutes ago, michael.h.f.wilkinson said:

BTW, the M42 image I posted was my first attempt with an autoguider on an EQ3-2. I think it shows better stars than the images posted on the Vaonis site

I agree :)

Here's one of the stars from the M81/82 image that looks to have diffraction spikes:

M81_M82.png.bb3a8a5dc090839793e90499f7ef5970.png

And this one from the Orion image I would say shows signs of further diffraction effects (alternating dark and bright bands) between the upper pair of bright spikes and again between the lower pair.  Having cropped the image it actually looks even more obvious to me.  I could be wrong there though.

M42.png.0096b47e0da18bf095d7294fb58a1666.png

 

James

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14 minutes ago, JamesF said:

I agree :)

Here's one of the stars from the M81/82 image that looks to have diffraction spikes:

M81_M82.png.bb3a8a5dc090839793e90499f7ef5970.png

And this one from the Orion image I would say shows signs of further diffraction effects (alternating dark and bright bands) between the upper pair of bright spikes and again between the lower pair.  Having cropped the image it actually looks even more obvious to me.  I could be wrong there though.

M42.png.0096b47e0da18bf095d7294fb58a1666.png

 

James

On second inspection, I spotted the ones on the M81 image as well. There also seem to be some CA issues with blue smeared out in one direction preferentially in the M42 crop. Pinched optics problem?

 

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Looks like a work in progress to me. Not long until March 31st !    :eek:

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I brought up the processing of the images of the Stellina on the eVscope Kickstarter page a while ago. People were trying to compare the images saying that the Vaonis Stellina was better. No one seemed to catch on until recently when someone else pointed out the diffraction spikes. There could be some mounting device in the optical path that is causing them, but they still appear to be processed even to my untrained eye.

Some don't seem to believe this type of scope will be good for outreach, but I disagree. You just have to be able to manage expectations of the public and explain the differences between a video astronomy/astrophotography setup and that of a standard telescope. Having this setup next to a large aperture dob or SCT and then a smaller reflector and refractor will really show the public what the capabilites of the different types of setups are and what to expect if they choose to get into the hobby. Everyone has seen the images of Hubble and these scopes in no way compare and that will be obvious to anyone who looks through them. What they do though, is show people the kinds of things that are really out there and continue to increase the interest in astronomy. And that is the whole point to public outreach. Educate, increase interest and inspire.

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