4138 replies to this topic

[eyeoftexas]

In my experience with testing many tens of telescopes, it is obvious that Seestar has better correction of chromatic aberration, better said spherochromatism. In my opinion there could be FCD100 glass which is equivalent to FPL-53. Vespera C and Vespera P have a significantly worse correction and have FPL-51, Vespera II has FPL-52.

If possible, could you post raw images from your Seestar and V-P of the same bright target with same acquisition parameters to illustrate this?  Not saying I don’t believe you, but it would be intriguing if this were true.

[smiller]

With respect to chromatic aberrations or other optical imperfections, I think that imaging correction algorithms could (and probably already do) go a long ways to mitigating them.   Especially if they are well characterized for a particular device.

 

It’s one thing to do it generally for any arbitrary configuration, but when you have an all-in-one design, you can really go to town in characterizing it to create algorithms specifically tuned to reduce the issues.

 

This has been how low cost point-and-shoot super-zoom camera manufacturers have enabled those very low cost systems to produce pretty darn good looking shots.  I’ve seen the raw data from a few example low cost imaging systems and it’s shocking what they do in imaging algorithms to make these systems perform.

 

Obviously near perfect optics is superior, you can never fully recover from imperfections, but I think that maximizing bang-for-the-buck will be a balance with providing “good enough” optics with exemplary imaging to make up much of the difference.

 

Just look at what BlurXterminator 2.0 is doing for pretty grotesque star quality in the corners of the optics for current standard systems.  One could argue what is actually happening there but it’s being adopted by many in the general AP community, so it’ll certainly be accepted in a more, what word to use…. casual/consumer oriented all-in-one scope.

Edited by smiller, 15 January 2024 - 11:33 AM.

[GSBass]

I have terrible star quality on my dwarf and it would be wonderful if they could apply bxt version 4 to the frames as they are stacked…. Perhaps wishing for too much but when you see dwarf images with nice stars you can just about count on it being from a bxt user

With respect to chromatic aberrations or other optical imperfections, I think that imaging correction algorithms could (and probably already do) go a long ways to mitigating them.   Especially if they are well characterized for a particular device.

 

It’s one thing to do it generally for any arbitrary configuration, but when you have an all-in-one design, you can really go to town in characterizing it to create algorithms specifically tuned to reduce the issues.

 

This has been how low cost point-and-shoot super-zoom camera manufacturers have enabled those very low cost systems to produce pretty darn good looking shots.  I’ve seen the raw data from a few example systems and it’s shocking what they do in imaging algorithms to make these systems perform.

 

Obviously near perfect optics is superior, you can never fully recover from imperfections, but I think that maximizing bang-for-the-buck will be a balance with providing “good enough” optics with exemplary imaging to make up much of the difference.

 

Just look at what BlurXterminator 2.0 is doing for pretty grotesque star quality in the corners of the optics for current standard systems.  One could argue what is actually happening there but it’s being adopted by many in the general AP community, so it’ll certainly be accepted in a more, what word to use…. casual/consumer oriented all-in-one scope.

[GSBass]

In practice, although no doubt better glass is always better, all these systems produce nice stars with the exception of dwarf, I’m not sure if it’s cheap glass or whether it’s the periscope system but stars on those units are noticeably flared/distorted…. With the software now maturing I can point to that as the main weakness of the system… it can be corrected if you have access to bxt, but it would seem that algorithm makes the whole discussion mute… if you have it…. I would be curious if the software makers are even open to letting manufactures use it… but sure seems like a no brainer

If possible, could you post raw images from your Seestar and V-P of the same bright target with same acquisition parameters to illustrate this?  Not saying I don’t believe you, but it would be intriguing if this were true.

[eyeoftexas]

In practice, although no doubt better glass is always better, all these systems produce nice stars with the exception of dwarf, I’m not sure if it’s cheap glass or whether it’s the periscope system but stars on those units are noticeably flared/distorted…. With the software now maturing I can point to that as the main weakness of the system… it can be corrected if you have access to bxt, but it would seem that algorithm makes the whole discussion mute… if you have it…. I would be curious if the software makers are even open to letting manufactures use it… but sure seems like a no brainer

I have no doubt that algorithms etc can make the images better.  My question, however, was addressed to the statement that S50 uses better optical glass than Vespera, and so I would like to see that somehow demonstrated.  That is, unless, single raw images are pre-processed so that a comparison is not possible.

[eyeoftexas]

But back to the new offering from Celestron.  I note in the description write-up on Astronomics it says “Celestron chose not to use their gold standard Schmidt Cassegrain, as it was slow at f/10 and didn't really meet the the requirements they were looking for”.  I wonder if they actually configured Origin using a C6/C8 SCT (which would probably have lowered the overall cost), would that have been preferred over the RASA used?  In my simple view, I would actually have preferred it because it would have been better than the other robots for small DSO’s, planets, and lunar.  As it is, I’ll continue to dither on going Vespera and wait for mosaic mode for the S50.

Edited by eyeoftexas, 15 January 2024 - 01:09 PM.

[smiller]

But back to the new offering from Celestron.  I note in the description write-up on Astronomics it says “Celestron chose not to use their gold standard Schmidt Cassegrain, as it was slow at f/10 and didn't really meet the the requirements they were looking for”.  I wonder if they actually configured Origin using a C6/C8 SCT (which would probably have lowered the overall cost), would that have been preferred over the RASA used?  In my simple view, I would actually have preferred it because it would have been better than the other robots for small DSO’s, planets, and lunar.  As it is, I’ll continue to dither on going Vespera and wait for mosaic mode for the S50.

High F-ratio scope plus a small sensor is just such a teeny tiny FOV.  Also, at high f-ratios and small pixel cameras the read noise from short exposures can actually start to become a material source of image degradation. 

 

Oh, also it even becomes hard to plateolve when you combine high f-ratio with a small sensor and short exposures.  I know because I try to do this, and there are limits as to how far you can go.

 

I really don’t see it going this way unless they do some type of “hyperstar’ish” thing, but that is what Origin kind of is.

Edited by smiller, 15 January 2024 - 01:18 PM.

[Psion]

If possible, could you post raw images from your Seestar and V-P of the same bright target with same acquisition parameters to illustrate this?  Not saying I don’t believe you, but it would be intriguing if this were true.

It's hard to compare, but when I process the Vespera image, I have to mask the blue halo around the bright stars a lot. Here's an unedited crop of two images from about 10 minutes of exposure on both instruments.

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[smiller]

The SeeStar seems to resolve the smaller dimmer stars.  Interesting…

[erff88]

i wonder how the seestar compares to vespera 2

[Starmix]

These pics shows a slight difference. Yes the Seestar shows a few of the fainter stars and less of a halo around the stars, but has more noise in the image than the Vespera. Maybe it’s just me, but I have to say I am not seeing a $1,500 difference between the two in these images.

 

Do wonder if the Origin’s images will be able to distinguish it from these two?

Edited by Starmix, 15 January 2024 - 03:02 PM.

[Psion]

I can see the difference, once the image is processed the halo comes out quite a lot. You have to remember that Vespera is F4 and Seestar F5, Vespera has 10% higher quantum efficiency, so a better Signal/Noise ratio of 1.7 times.

 

The Celestron Origin will do better with a S/N ratio of 2.9 times than the Seestar and 1,7 times than the Vespera Passengers.

Edited by Psion, 15 January 2024 - 03:31 PM.

[eyeoftexas]

It's hard to compare, but when I process the Vespera image, I have to mask the blue halo around the bright stars a lot. Here's an unedited crop of two images from about 10 minutes of exposure on both instruments.

Thanks for this.  I agree that there are bluish halos in the V-P image that are absent from the S50 image.  This should manifest itself a lot on lunar images. 

[GSBass]

The difference in price is fov, mp and software but that’s been covered multiple times, 50mm is 50mm and barring any defects the images will be similar…. , whether it’s optics or processing, Vaonis products do show blue on brighter stars, that includes v2 and may include pro also. And yes there should be much improved images from a 6” system, if not then they did a poor job

These pics shows a slight difference. Yes the Seestar shows a few of the fainter stars and less of a halo around the stars, but has more noise in the image than the Vespera. Maybe it’s just me, but I have to say I am not seeing a $1,500 difference between the two in these images.

 

Do wonder if the Origin’s images will be able to distinguish it from these two?

Edited by GSBass, 15 January 2024 - 03:34 PM.

[eyeoftexas]

High F-ratio scope plus a small sensor is just such a teeny tiny FOV.  Also, at high f-ratios and small pixel cameras the read noise from short exposures can actually start to become a material source of image degradation. 

 

Oh, also it even becomes hard to plateolve when you combine high f-ratio with a small sensor and short exposures.  I know because I try to do this, and there are limits as to how far you can go.

 

I really don’t see it going this way unless they do some type of “hyperstar’ish” thing, but that is what Origin kind of is.

I was more thinking of designing the whole thing around the SCT, not simply replace the RASA with it and not change the sensor, etc.  But I see your point.  The guiding/plate solving could be solved with an external guide scope driving the system, but that does make things more and more complicated.  As I said, I was hoping for (and still hope for) a robot that is good for planets, lunar, and galaxies.  

[eyeoftexas]

The difference in price is fov, mp and software but that’s been covered multiple times, 50mm is 50mm and barring any defects the images will be similar…. , whether it’s optics or processing, Vaonis products do show blue on brighter stars, that includes v2 and may include pro also.

Indeed.  It’s clear that the major difference between the S50 and the Vespera line is the app.  I would be more inclined to jump on the V wagon if they would have included the filters, which tacks another $300+ on the cost. 

[Psion]

By the way, the blue halo also shows Celestron Origin.

[eyeoftexas]

By the way, the blue halo also shows Celestron Origin.

Chromatic aberration from a reflector?

[Psion]

Yes because the RASA has a correction plate, which is actually a lens in the optical path.

[kgb]

By the way, the blue halo also shows Celestron Origin.

I cannot imagine that a RASA is showing CA around stars. Please provide a link where the Origin shows CA please.

[GSBass]

No blue is seen in vespera lunar images, however in my opinion vespera is one of the worst on the moon because you have no manual control, you can capture decently and they look better if stacked, but it’s a feature on our wishlist and we speculate the work they are doing with their gravity app will make its way in to singularity, this should improve lunar and solar substantially across the whole product line….. I also expect origin will beat all the robots in lunar and planetary detail… again 50mm vs 6” … the large obstruction will not be great for high contrast but still expect it to win easily

Thanks for this.  I agree that there are bluish halos in the V-P image that are absent from the S50 image.  This should manifest itself a lot on lunar images. 

[Psion]

I cannot imagine that a RASA is showing CA around stars. Please provide a link where the Origin shows CA please.

There are no usable images from Origin yet, but RASA, like SCT, can make a blue halo. I have both RASA 8" and SCT Meade ACF.

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[GSBass]

I’m not going to get in to the weeds of this but I honestly think the culprit is more about choices they make in processing than optics…. There may be some trade offs that zwo made that others decided not to make, images are much brighter in the same amount of time on Vaonis products, some of that may be f stop but I think a lot of it is the way it’s tuned

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btw I personally don’t have issues with the blue, looks somewhat natural to me, I do attenuate it some in post but I don’t make an effort to get rid of it completely in my photos

I cannot imagine that a RASA is showing CA around stars. Please provide a link where the Origin shows CA please.

Edited by GSBass, 15 January 2024 - 03:57 PM.

[jimhoward999]

High F-ratio scope plus a small sensor is just such a teeny tiny FOV.  Also, at high f-ratios and small pixel cameras the read noise from short exposures can actually start to become a material source of image degradation. 

 

Oh, also it even becomes hard to plateolve when you combine high f-ratio with a small sensor and short exposures.  I know because I try to do this, and there are limits as to how far you can go.

 

I really don’t see it going this way unless they do some type of “hyperstar’ish” thing, but that is what Origin kind of is.

I think a "hyperstarish thing" would be a great way to go.   Based on a SCT rather than a Newtonian you could have a compact system with more aperture.  Then you could a more reasonable 1" format camera while maintaining a moderate central obstruction.

 

That would be what many custom EAA set-ups that people build look like.  Add robotic software and they would have a nice system.  And the cost would probably be only a couple thousand dollars more....better value to my way of thinking.

Edited by jimhoward999, 16 January 2024 - 09:31 AM.

[kgb]

There are no usable images from Origin yet, but RASA, like SCT, can make a blue halo. I have both RASA 8" and SCT Meade ACF.

Those halos are around bright stars and are likely due to the reflection of filters in the system and/or increased saturation during processing. Those halos are not the same as the violet/blue fringe identified in the prior photos.

Edited by kgb, 15 January 2024 - 04:02 PM.