540 replies to this topic

[Psion]

I would also assume that ZWO used a standard UV/IR filter that uses, then the 400-700nm range and there is no reason to block Ha or OIII. Plus, Ha is 20nm, and OIII is 30nm, so you can narrow the bandwidth even further with an LP filter inserted. I don't see any problem with this.

[GSBass]

That would be a fair assumption if his filter performed as expected, but it didn’t so we are just speculating at the cause, he will figure it out… might have nothing to do with the ir/cut, but all ir/cuts are not created equal so it’s possible, someone will probably do a test with the l’enhance soon and I know that one should perform well with the 462c

I would also assume that ZWO used a standard UV/IR filter that uses, then the 400-700nm range and there is no reason to block Ha or OIII. Plus, Ha is 20nm, and OIII is 30nm, so you can narrow the bandwidth even further with an LP filter inserted. I don't see any problem with this.

[Psion]

Yesterday I tested the Altair TriBand 1.25" Filter while shooting the Cocoon Nebula with the eVscope from the city. I turned out just as bad. The nebula was much better without the filter. Why? Very short exposures are unsuitable for narrow filters, especially in bad skies. On objects that are bright a filter works e.g. M27. I think Cuiv has run into the same problem. I can prove this with pictures, it you want. 

[eyeoftexas]

Yesterday I tested the Altair TriBand 1.25" Filter while shooting the Cocoon Nebula with the eVscope from the city. I turned out just as bad. The nebula was much better without the filter. Why? Very short exposures are unsuitable for narrow filters, especially in bad skies. On objects that are bright a filter works e.g. M27. I think Cuiv has run into the same problem. I can prove this with pictures, it you want. 

Yes, please, provide pictures. Also, please explain how short exposures are unsuitable. Is it simply that there is less data per image, because then adding more images to the stack would make it fine.

[Psion]

Very short exposures with LP filters will have relatively low levels of sky background noise, though, so reading noise from an uncooled camera contributes significantly to the overall noise in the image (thermal and read). If there is sufficient diameter of the Telescope or objects are bright e.g. M57,M27, M20, M42, etc. then the camera reading noise will not apply as much. If we take 100 exposures of 4 seconds, there will be 10 times more (SQRT 100) read noise in the image than for a single exposure of 400 seconds, so the signal-to-noise ratio will be quite tragic.

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Edited by Psion, 10 September 2023 - 08:36 AM.

[GSBass]

It must come down to the suitability of this particular filter, I have no issues imaging using 10sec subs with the l’enhance

Very short exposures with LP filters will have relatively low levels of sky background noise, though, so reading noise from an uncooled camera contributes significantly to the overall noise in the image (thermal and read). If there is sufficient diameter of the Telescope or objects are bright e.g. M57,M27, M20, M42, etc. then the camera reading noise will not apply as much. If we take 100 exposures of 4 seconds, there will be 10 times more (SQRT 100) read noise in the image than for a single exposure of 400 seconds, so the signal-to-noise ratio will be quite tragic.

[Psion]

Both filters, i.e. Altair Triband and ZWO dual band are quite similar. Triband has O III 34 nm and Ha 14 nm, ZWO LP has O III 30 nm and Ha 20 nm. Unfortunately, the 50mm telescope diameter and especially the F5 gives very little light into the 2.9 um pixel. L-eNhance has O III 24 nm, Ha 10 nm.

[GSBass]

Does not really make sense for my l’enhance to work so well and these others not… I am using same sensor and aperture, only software is different and I capture pretty nice images with it here is one exposure from the other night with l’enhance of eagle https://x.com/artemi...1XgzO5JXF9NadZA

Both filters, i.e. Altair Triband and ZWO dual band are quite similar. Triband has O III 34 nm and Ha 14 nm, ZWO LP has O III 30 nm and Ha 20 nm. Unfortunately, the 50mm telescope diameter and especially the F5 gives very little light into the 2.9 um pixel. L-eNhance has O III 24 nm, Ha 10 nm.

[GSBass]

And here is 76min on Cygnus loop with l’enhance 10sec subs https://x.com/artemi...1XgzO5JXF9NadZA

Both filters, i.e. Altair Triband and ZWO dual band are quite similar. Triband has O III 34 nm and Ha 14 nm, ZWO LP has O III 30 nm and Ha 20 nm. Unfortunately, the 50mm telescope diameter and especially the F5 gives very little light into the 2.9 um pixel. L-eNhance has O III 24 nm, Ha 10 nm.

[Psion]

You're saying this is an unedited Vespera image, which is impossible? What telescope is this from?

[GSBass]

Yes this is vespera, not unedited, they are the tiffs stretched… here is just the wild duck cluster completely unedited, but no nebulosity and this one was with badder neodymium instead of l’enhance… unedited images in vespera are served as jpgs https://x.com/artemi...1XgzO5JXF9NadZA

You're saying this is an unedited Vespera image, which is impossible? What telescope is this from?

[Psion]

Vaionis has small FOV, so is it a mosaic of approximately 8 frames and an exposure of 76 minutes in total?

[GSBass]

Yeah, the way CovalENS works is your presented with a star map of your target, it has a box you can drag around, you can make it a square or skinny and long… the only rule is it has to be between 2mp sensor size and 8mp maximum, a square at maximum is 2.4 by 2.4 degrees, sensor size is 1.6 x .09 degrees. After you have drawn your box you can then rotate your target with in it for composition. Then you hit go… vespera will start taking photos and move building the image from the inside out. For maximum size it takes about an hour to complete the first pass, at minimum size it takes 15 minutes or so… but the picture continues to improve the more passes you let it run because the process does a dithering affect that eliminates noise… including pattern noise…. Pretty cool algorythm… makes beautiful images

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for clarity , the scope moves between each frame so every time it stacks the image is expanded a small percentage… it just keeps doing that until the full picture is complete… as a general rule of thumb it takes 1/3rd longer… so an hour of data will cost you 1.5hrs of real-time 

Vaionis has small FOV, so is it a mosaic of approximately 8 frames and an exposure of 76 minutes in total?

Edited by GSBass, 10 September 2023 - 03:44 PM.

[Psion]

Thank you for the clarification. I can also take a better picture of the Cocoon Nebula through the Triband filter, but I need 30-40 minutes, versus the usual 15-20 minutes without the filter. That seems too long for EAA. If I point a RASA 8" at the sky and a camera with the same chip that eVscope has, an IMX 224 (for example, an ASI 224 camera), I can get a significantly better image in as little as 2 minutes with the Triband filter. This is 38 minutes.

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Edited by Psion, 10 September 2023 - 04:37 PM.

[GSBass]

Many people like to think of these as eaa scopes but the reality is it does take a while for the photons to accumulate at this aperture, Vaonis provides recommended timeframes for objects in their catalog, withe the exception of the super bright stuff like Orion, most are at least 30 min, a lot are an hour and the real dim stuff might be 2hrs…. On the bright side you can watch a movie while it comes in next to you. There is no reason to assume seestar will be any different

Thank you for the clarification. I can also take a better picture of the Cocoon Nebula through the Triband filter, but I need 30-40 minutes, versus the usual 15-20 minutes without the filter. That seems too long for EAA. If I point a RASA 8" at the sky and a camera with the same chip that eVscope has, an IMX 224 (for example, an ASI 224 camera), I can get a significantly better image in as little as 2 minutes with the Triband filter.

[Psion]

If we compare the Vaonis Stellina (a friend has this device), it seems to me that the Seestar produces significantly better images with more dynamics. As we know, the software matters a lot, I would say at least 50% for the image quality.

[GSBass]

Stellina is capable of very good images , the extra aperture will show more detail than a 50mm, however the design is getting fairly old and it has trouble keeping up with the newer algorithms, it also has a non removable cls filter which takes longer to capture broadband targets, on the plus side it had a hardware derotater which was nice. Vaonis already announce the successor to vespera and I expect a stellina replacement to be announced in the spring also. The new vespera has a square 12 mp chip and added field flattener, it will go up to 32mp in CovalENS mode

If we compare the Vaonis Stellina (a friend has this device), it seems to me that the Seestar produces significantly better images with more dynamics. As we know, the software matters a lot, I would say at least 50% for the image quality.

[Psion]

I ordered a Vespera PRO 2 months ago, I'm curious how it will work with the new straightener and better chip. Then I can compare it with the cheap Seestar.

[safinsd]

Looking forward to receiving the Vespera Pro to augment my Stellina. I'm passing on the Seestar and Hestia.

[safinsd]

If we compare the Vaonis Stellina (a friend has this device), it seems to me that the Seestar produces significantly better images with more dynamics. As we know, the software matters a lot, I would say at least 50% for the image quality.

I haven't seen any edited Seestar images yet that rival the best Stellina images derived from stacks of lights and darks. Perhaps that will change if Seestar provides fits lights and darks.

Edited by safinsd, 11 September 2023 - 10:17 AM.

[GSBass]

I passed on seestar but was curious to play with hestia… I figured for 149 it would be fun to try…. If I end up not using it I’ll probably give it to my daughter. A lot might depend on if I keep my dwarf, I can see hestia becoming my main solar scope if I don’t

Looking forward to receiving the Vespera Pro to augment my Stellina. I'm passing on the Seestar and Hestia.

[eyeoftexas]

Speaking of the Dwarf, has there been any updates on social media about when the new app might be coming out?

[GSBass]

No…. And the beta I received yesterday is not the rewrite… so no clue…. I could not even test the feature they wanted me to because they required I use a computer hooked to dwarf to access the memory card…. I’m not going to do that… lots of customers only have a phone or tablet and they need to get out of the mindset of requiring a computer for any operations imho. The new panorama algorythm is currently not in camera… they have it running on an external server…. However you still can’t get access to those files with your phone or tablet to upload them so the beta test stopped before it begun

Speaking of the Dwarf, has there been any updates on social media about when the new app might be coming out?

[GSBass]

I think the only thing about seestar that would actually bother me is the fov, when you take field rotation in to account you can’t even get all of Orion in, they maybe should have either stuck with 200mm or used a larger chip, the imx464 is just as cheap and equivalent in performance to the imx462. I know they are planning on mosaics but that will take twice the time to make one. On the bright side image scale of the small stuff may benefit

[Psion]

The problem with a large field of view must then be solved with a shorter exposure. It would be nice if Seestar could rotate the chip by a defined number of degrees to make a better composition.

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