3947 replies to this topic

[tarbat]

I have a previous post somewhere else on CN about elongated stars in the top right corner. I solved this by using the manual focus to go from one extreme focus to the other extremity, and that fixed the elongated stars.  I suspect that with the focuser being connected to the sensor, somehow the sensor alignment can be affected by the focuser.

[Psion]

Could it be due to the poor tempering of the telescope?

[rimcrazy]

I also have two photos where the stars in the upper right corner are stretched into an ellipse, but the other photos are fine, so it must be the software and processing too and not the optics.

Hmm I take back what I said.  I did a quick look at the finished but unprocessed images from my Seestar and the stars are all quite round, corner to corner so I am not seeing what you are seeing.  Perhaps you have a level issue but I would contact ZWO and see what they have to say about it first.

[Mojave Red]

Nearly full moon this evening.

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[photon08]

I have a previous post somewhere else on CN about elongated stars in the top right corner. I solved this by using the manual focus to go from one extreme focus to the other extremity, and that fixed the elongated stars.  I suspect that with the focuser being connected to the sensor, somehow the sensor alignment can be affected by the focuser.

Thank you. I don't see any ui for the manual focus in the app. How did you focus manually? 

[photon08]

Hmm I take back what I said.  I did a quick look at the finished but unprocessed images from my Seestar and the stars are all quite round, corner to corner so I am not seeing what you are seeing.  Perhaps you have a level issue but I would contact ZWO and see what they have to say about it first.

 

A level issue is certainly a possibility. In my case, stars are not just elongated but are of rather funny shape. I'll contact zwo. 

[Psion]

Hmm I take back what I said.  I did a quick look at the finished but unprocessed images from my Seestar and the stars are all quite round, corner to corner so I am not seeing what you are seeing.  Perhaps you have a level issue but I would contact ZWO and see what they have to say about it first.

I emailed them a few days ago with the attached pictures, but I am still waiting for a reply.

[Psion]

In all photos in the constellation Cygnus, there is a problem in the upper right corner, and exposures were from 2 to 26 minutes at 20.00-23.00 hours. I then moved the telescope to the nebula IC1396, and after 36 minutes of exposure, the stars were round. Either moving to a different constellation moved something, or the ambient and telescope temperature equalized, I have no other explanation. It seems to me that the stars are getting rounder over time.

 

 

 

Edited by Psion, 28 October 2023 - 03:42 AM.

[tarbat]

In all photos in the constellation Cygnus, there is a problem in the upper right corner, and exposures were from 2 to 26 minutes at 20.00-23.00 hours. I then moved the telescope to the nebula IC1396, and after 36 minutes of exposure, the stars were round.

Did you perhaps change the focus when you moved it to IC1396?

[Psion]

I don't think I changed the focus, but unfortunately, I don't remember. I'll try focusing on different areas during shooting.

[Psion]

Reprocessed moon, better resolution and slight adjustment.

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[rimcrazy]

Here are some new ones from last night.  I included both the raw Seestar final images as they are loaded on my iPhone and then the post PI/Photoshop processed versions I finished out.

 

First up is IC1795.  Had not heard of this object before but just picked it out of the suggested objects for the night.

 

Here is the raw version straight out of the Seestar.  This image was just over 1hour of exposure.

 

Here is the finished version after my post processing.  You can see I removed some satellite trails using Photoshop as well as some other cleaning up.

 

Here is the raw M42 image.  I re-centered this as I did not like how the Seestar originally positioned this to be photographed.  This was only a 2.5min exposure BTW.

 

Here is the finished M42 image

 

Here is M45, the Pleiades, raw from the Seestar.  This is a 1.25hr exposure.

 

Here is M45 post processed.  I was hoping to get a lot more nebulosity in the image but even after 1.25 hours there is little to none of the famous blue gas clouds.

 

 

 

 

 

 

[photon08]

In my case, stars are not oval but more like "trapezoids" with curved sides. I suspect that this is caused by the combination of bad tracking and too long sub exposure because I have seen something similar with my dobsonian for high altitude object near the meridian when I tried to increase the sub length. When I cut down the sub exposure length, it got better.

One mystery is that some stars have "wings' or a " tail" that I attribute to the bad collimation in a reflector (with both eVscope and Dobsonian, improving the collimation made them disappear). I didn't expect to see that in a refractor like Seestar.

This bad star shape and too low a duty cycle (67% in the perfect sky condition due to 5 sec overhead for every 10 sec frame) made Seestar rather disappointing to me.

I hope that the former is the user error (on me) and that I can fix it somehow. As for the latter, I hope ZWO will increase the duty cycle at least to 90%.

[Astro Sky]

Oct 24th night M 33 - 6 min.

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[Astro Sky]

Oct 24th Moon

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[Mojave Red]

Almost full moon.

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[dokuzbm]

First attempt with Seestar S50 on NGC 7000. With a little help from SIRIL and Affinity. Greetings from Germany.

 

 

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[bartholomule]

Here's one of the sun I got with my seestar last week.  10 minutes of video (the seestar app max) processed in ASIVideoStack from ASIStudio.

 

Here's one of NGC281 from last week as stacked and output by the device, converted to jpg by pixinsight with a bit of a stretch:

 

And me attempting to quickly process those 558 frames of NGC281 in pixinsight (still needs background removal):

The resolution of the device is a bit of a limiting factor, especially for long stacked sequences where massive cropping happens.  A 1.5 hour stack is probably not a good idea.

[Psion]

In Zenith, there's a significant narrowing of the field of view. Suppose one wants to get the most out of the telescope, saving a photo every 25 minutes and then stacking the separate Fit files stored in the telescope in Siril or a similar program. This will give a significantly better photo. You can see in the video that 25-35 minutes is fine, you can see the problem after 45 minutes.

 

https://www.youtube....h?v=UW76pQ_ez1I

[Wildetelescope]

I have a previous post somewhere else on CN about elongated stars in the top right corner. I solved this by using the manual focus to go from one extreme focus to the other extremity, and that fixed the elongated stars.  I suspect that with the focuser being connected to the sensor, somehow the sensor alignment can be affected by the focuser.

How do you do manual focus? I thought that was not an option currently?   

 

JMD

[Wildetelescope]

 Thank you for introducing me to BXT and NXT as well as for the reply. I haven't used Pixinsight since trying it out a couple of years ago because I had thousands of very short exposure subs to process taken with a Dobsonian and Pixinsight's preprocessing took so much longer than alternatives and took up so much disk space (its own image format is bloaty and preprocessing step keeps all the intermediary files around). Perhaps, I'll try to use it for postprocessing of stacked images or images off from seestar. Besides, now that I have an eq mount (az gti with wedge) and can have longer exposure subs, I meant to try it again even though I'm happy with Siril.

 

Going back to the original question, I may be hallucinating , but images directly taken off from Seestar (I believe,) without any postprocessing seem to have better star shape than mine. I also remember reading or watching a video where it's mentioned that seestar images have round stars except in the upper right corner. So, I had a higher expectation. 

Stacking artifacts are one possibility.  Take the raw subs and stack them in a third party software, which is what many folks here are doing.  A second is that lens quality might very a bit and different lens might see a small amount of astigmatism.  this is not unexpected for something in this price range.  Finally, focusing is achieved by either moving the lens or the sensor(not clear which approach is used), so it is not at all surprising that one might see a bit of tilt from the images.  Folks spend a lot of time with standard(much more expensive) imaging rigs fussing with their imaging train to minimize this. 

 

I have been very impressed with the performance of my Seestar out of the box, relative to what it costs.   The final test of this gear is how well everything is working a year from now.   There are a lot of things moving inside the little black box and over time stuff is going to wear.  It is probably going to be sensitive to shock and vibration over time as well.  This is not meant to be a criticism.   The darn thing works really well. 

 

JMD

[tarbat]

How do you do manual focus? I thought that was not an option currently?

Manual focus is available in Stargazing mode. The focus motor appears to operate on the sensor, and I've speculated that this may be the cause of occasional elongated stars in the top-right corner. I've eliminated them on my Seestar by moving the focus to both extreme extents, and I now have round stars across the whole field of view.

 

Edited by tarbat, 31 October 2023 - 10:24 AM.

[jprideaux]

Stacking artifacts are one possibility. Take the raw subs and stack them in a third party software, which is what many folks here are doing. A second is that lens quality might very a bit and different lens might see a small amount of astigmatism. this is not unexpected for something in this price range. Finally, focusing is achieved by either moving the lens or the sensor(not clear which approach is used), so it is not at all surprising that one might see a bit of tilt from the images. Folks spend a lot of time with standard(much more expensive) imaging rigs fussing with their imaging train to minimize this.

I have been very impressed with the performance of my Seestar out of the box, relative to what it costs. The final test of this gear is how well everything is working a year from now. There are a lot of things moving inside the little black box and over time stuff is going to wear. It is probably going to be sensitive to shock and vibration over time as well. This is not meant to be a criticism. The darn thing works really well.

JMD

I did a drop-test a couple weeks ago with both my SeeStar and my Vespera. I was carrying them both (fortunately in protective cases) in the dark on the way to my car in my driveway and tripped on something and did a shoulder roll on the concrete and both telescopes hit the concrete and went sliding a bit. I then proceeded to pick them both up and drive to my dark site. Both still performed fine and I have used both since then on a couple additional occasions.

When I tripped, my SeeStar was in its styrofoam case. My Vespera was in its padded backpack. Both turned out to be good protection.

[eyeoftexas]

I did a drop-test a couple weeks ago with both my SeeStar and my Vespera. I was carrying them both (fortunately in protective cases) in the dark on the way to my car in my driveway and tripped on something and did a shoulder roll on the concrete and both telescopes hit the concrete and went sliding a bit. I then proceeded to pick them both up and drive to my dark site. Both still performed fine and I have used both since then on a couple additional occasions.

When I tripped, my SeeStar was in its styrofoam case. My Vespera was in its padded backpack. Both turned out to be good protection.

Thanks for going the extra mile to fully test these scopes 

[KenF9000]

1st ever deepsky with the S50, circa 20min exposure, bortle 4.5. Post processed in Siril, after watching a couple of youtube tutorials, so very much still finding my feet with both.

M81/M82.

 

 

Please feel free to comment and critique