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#226 a__l

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Posted 09 January 2021 - 08:43 PM

Hi!

 

We were able to take our first photo of the horsehead nebula today.

What the Smartphone couldn't do, was now possible with the ZWO ASI 178 MC camera adapted to the night vision device.

 

OVNI-O with 12nm H-Alpha filter

60/330 TS Photoline telescope

100 frames of 1 second each, stacked with Deep Sky Stacker.

It is interesting to see with your own eye ... without using photographic equipment and methods of adding frames. You probably won't be able to do this on your dobson.


Edited by a__l, 09 January 2021 - 08:43 PM.


#227 Kathi

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Posted 10 January 2021 - 03:59 AM

It is interesting to see with your own eye ... without using photographic equipment and methods of adding frames. You probably won't be able to do this on your dobson.

Yes, it is!

We look forward to being able to do that.

But we can't see it with our current night vision device. It's just too weak for the horse's head.
We tried many times visually but it doesn't work.

 

But the new night vision device has already been ordered. Delivery time 3 months.

We are really looking forward to it!

 

Kathi

 



#228 Jeff Morgan

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Posted 13 January 2021 - 11:06 PM

Sharpless 2-119 was one of my early "discoveries" with NV - sweeping up a large and bright nebula where - according to my star charts - was nothing but empty sky.

 

https://www.cloudyni...very/?p=7550775

 

What fun that was! 

 

Finally, I have a scope with enough true field to do it justice. Had I updated the Epsilon to a 2" focuser that probably would have worked too.

 

 

Attached Thumbnails

  • IMG_6704.jpeg

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#229 Jeff Morgan

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Posted 20 January 2021 - 10:57 AM

Last gasp at the summer Milky Way, M71 in Sagitta shot in November.

 

A very small target, so I used the 2.5x Powermate for an effective focal ratio of f/17.5, perfectly fine for clusters.

Attached Thumbnails

  • M 71 TMB 130SS 2.5PM.jpeg

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#230 Subspacetransmitter

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Posted 27 January 2021 - 08:48 AM

The Crab Pulsar (PSR B0531+21):

 

After many cloudy weeks a usable starry sky showed up here in Radebeul (Germany) again, I used the opportunity and started another attempt to finally resolve the pulsar in M1 temporally and spatially. After the first experiments some weeks before it was clear that this faint part cannot be resolved directly in time even with a night vision device (OVNI-M), at least not with our astronomical conditions and with the for such a thing rather "small" 24" Dobsonian. But then I had an idea to crack the thing after all. According to my research on the pulsar, it has two maxima in the 33.5ms of its period, one bright and one fainter, both lasting about 5ms. This results in the minimum necessary exposure time (5ms). In addition, the pulsar is very close to another star and must be spatially resolved accordingly. So I extended the focal length, which also helps to recognize the pulsar, because the high background brightness due to the nebula is reduced.

On a 5ms frame you can't recognize stars with 15 or 16 mag even with a cooled CMOS camera + NVD, for that the noise too high. The only option, as is often the case, is to stack enough images to get the faint pulsar out of the noise.  That's when I had the idea to use our QHY-174M-GPS camera, which is actually there to measure star occultations by asteroids and can set an accurate GPS time stamp. With this, one could assign to each frame its exact location in the period of the pulsar, and then stack them precisely. For this purpose I equipped the telescope with the Baader-FFC, the OVNI-M NVD without lens/eyepiece and the QHY camera with a 50mm f/1.4 lens.  But this construction was too much for the focuser and I had to fight with image field tilts. But in the end I accepted it, there is no other way. The NVD was running at maximum gain and also the camera was at the limit with the gain but cooled down to -40°C.

I made many video sequences and tried a little bit, here is an example video: https://www.dropbox...._Video.avi?dl=0 The video has 3035 frames and was recorded for about 15s. Unfortunately the tracking is already so inaccurate in this short time that you need a star for stacking, so I took the brighter star at the bottom still in the field of view. If you look at the video, you can see just three stars in total. But the recording was the easier part in the end.

 

Then I had to get the timestamp from the single images, rounded appropriately, into the file name. For this I searched for a long time for a useful OCR software. It would be easier if the SharpCap would do it right away (somehow I couldn't manage that). Then I built an Excel table and took the timestamp of the first image as the beginning of the period. Then you need the exact period of the pulsar (0,033781965), which changes every year, I didn't know that before. Now I always add the full frequency to the first timestamp for the complete recording period. This resulted in the end in a column with nearly 500 values (times) in my case. Then you have to do the same for the remaining 33ms of the period (each new column +1ms). Then I built a program to find the frames matching the period time and copy them into the corresponding folders. In the end I had 34 folders with about 80 frames in each. I stacked them all manually in Fitswork, the flashing of the NVD makes an automatic detection of even the brightest star impossible. Since the star was also not clearly visible everywhere, I could usually only really use 50-60 images.

The chance that this really works out I had rather classified as low, it was completely unclear whether the time stamp of the camera is accurate enough and whether the OVNI-M can even resolve 5ms in time. But it really worked and in the animation you can see the main and the secondary maxima cleanly separated. The image quality is grotty but it worked smile.gif  With a bigger telescope, better seeing and less noise I'm sure it would work without stacking, but I don't have it. Nevertheless I am very satisfied and happy with the results smile.gif  The image with the arrow is a average image from all frames of the animation. By the averaging the pulsar is clearly fainter than the near comparison star even if it is actually brighter in the maximum.

 

Animation:

 

http://galerie2.astr...tion_Medium.gif

 

Setup:

 

http://galerie2.astr..._Uebersicht.jpg

http://galerie2.astr...hnik_Detail.jpg

 

Best
Martin

Attached Thumbnails

  • vorschau.jpg

Edited by Subspacetransmitter, 27 January 2021 - 08:51 AM.

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#231 cnoct

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Posted 27 January 2021 - 09:28 AM

Wow, just wow shocked.gif . 

 

Wish this observing report, with your detailed content wasn't going to get lost in this image threads, consider moving if allowed, to the main NV astro arena. There's just so much hard work and great detail on your technique and the capture itself. 

 

I'm grateful for the privilege to benefit from all your thought and effort devoted to capturing this, thank you for this.

 

 


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#232 Subspacetransmitter

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Posted 27 January 2021 - 10:11 AM

Thank you very much for your comment. The entry can of course be moved by an admin if needed. I had only posted it here, because the animation has required a "little bit" of image processing...



#233 ButterFly

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Posted 28 January 2021 - 12:27 PM

Definitely submit that for APOD.  Incredible work


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#234 astrocanito

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Posted 30 January 2021 - 07:06 AM

Incredible work. Thank you!


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#235 Bewareredzone1786

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Posted 30 January 2021 - 05:02 PM

does anyone know what this is?


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#236 GeezerGazer

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Posted 31 January 2021 - 03:00 PM

The Crab Pulsar (PSR B0531+21):

 

 

Animation:

 

http://galerie2.astr...tion_Medium.gif

 

Setup:

 

http://galerie2.astr..._Uebersicht.jpg

http://galerie2.astr...hnik_Detail.jpg

 

Best
Martin

Martin, your image gallery is spectacular and the animation video for the pulsar is great!  Thanks for posting.  Good work there and congratulations on your success.

Ray


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#237 dclt

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Posted 06 February 2021 - 11:50 AM

The Crab Pulsar (PSR B0531+21):

After many cloudy weeks a usable starry sky showed up here in Radebeul (Germany) again, I used the opportunity and started another attempt to finally resolve the pulsar in M1 temporally and spatially. After the first experiments some weeks before it was clear that this faint part cannot be resolved directly in time even with a night vision device (OVNI-M), at least not with our astronomical conditions and with the for such a thing rather "small" 24" Dobsonian. But then I had an idea to crack the thing after all. According to my research on the pulsar, it has two maxima in the 33.5ms of its period, one bright and one fainter, both lasting about 5ms. This results in the minimum necessary exposure time (5ms). In addition, the pulsar is very close to another star and must be spatially resolved accordingly. So I extended the focal length, which also helps to recognize the pulsar, because the high background brightness due to the nebula is reduced.

On a 5ms frame you can't recognize stars with 15 or 16 mag even with a cooled CMOS camera + NVD, for that the noise too high. The only option, as is often the case, is to stack enough images to get the faint pulsar out of the noise. That's when I had the idea to use our QHY-174M-GPS camera, which is actually there to measure star occultations by asteroids and can set an accurate GPS time stamp. With this, one could assign to each frame its exact location in the period of the pulsar, and then stack them precisely. For this purpose I equipped the telescope with the Baader-FFC, the OVNI-M NVD without lens/eyepiece and the QHY camera with a 50mm f/1.4 lens. But this construction was too much for the focuser and I had to fight with image field tilts. But in the end I accepted it, there is no other way. The NVD was running at maximum gain and also the camera was at the limit with the gain but cooled down to -40°C.

I made many video sequences and tried a little bit, here is an example video: https://www.dropbox...._Video.avi?dl=0 The video has 3035 frames and was recorded for about 15s. Unfortunately the tracking is already so inaccurate in this short time that you need a star for stacking, so I took the brighter star at the bottom still in the field of view. If you look at the video, you can see just three stars in total. But the recording was the easier part in the end.

Then I had to get the timestamp from the single images, rounded appropriately, into the file name. For this I searched for a long time for a useful OCR software. It would be easier if the SharpCap would do it right away (somehow I couldn't manage that). Then I built an Excel table and took the timestamp of the first image as the beginning of the period. Then you need the exact period of the pulsar (0,033781965), which changes every year, I didn't know that before. Now I always add the full frequency to the first timestamp for the complete recording period. This resulted in the end in a column with nearly 500 values (times) in my case. Then you have to do the same for the remaining 33ms of the period (each new column +1ms). Then I built a program to find the frames matching the period time and copy them into the corresponding folders. In the end I had 34 folders with about 80 frames in each. I stacked them all manually in Fitswork, the flashing of the NVD makes an automatic detection of even the brightest star impossible. Since the star was also not clearly visible everywhere, I could usually only really use 50-60 images.

The chance that this really works out I had rather classified as low, it was completely unclear whether the time stamp of the camera is accurate enough and whether the OVNI-M can even resolve 5ms in time. But it really worked and in the animation you can see the main and the secondary maxima cleanly separated. The image quality is grotty but it worked smile.gif With a bigger telescope, better seeing and less noise I'm sure it would work without stacking, but I don't have it. Nevertheless I am very satisfied and happy with the results smile.gif The image with the arrow is a average image from all frames of the animation. By the averaging the pulsar is clearly fainter than the near comparison star even if it is actually brighter in the maximum.

Animation:

http://galerie2.astr...tion_Medium.gif

Setup:

http://galerie2.astr..._Uebersicht.jpg
http://galerie2.astr...hnik_Detail.jpg

Best
Martin


Very impressive shot.
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#238 Joko

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Posted 09 February 2021 - 02:21 AM

The Crab Pulsar (PSR B0531+21):

APOD !!!

Congratulations to Subspacetransmitter for the 1st ever APOD using a Night Vision eyepiece.

https://apod.nasa.go...d/ap210209.html


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#239 R_Huntzberry

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Posted 13 February 2021 - 02:16 AM

Congratulations Subspace transmitter!


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#240 Jeff Morgan

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Posted 17 February 2021 - 07:29 AM

Last November I was able to get a few more northern Milky Way shots. Here is open cluster NGC 6940 using the Antares 0.7x focal reducer.

 

That reducer is one of my favorite NV accessories, yet I don't have many images using it. Just a matter of target framing and random chance really. It gives very sharp performance. Unfortunately, this particular image had some camera tilt, as you can see by comparing the Left and Right edges of the image <sigh>.

Attached Thumbnails

  • NGC 6940 TMB 130SS 0.7R.jpeg


#241 Deadlake

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Posted 17 February 2021 - 10:54 AM

Last November I was able to get a few more northern Milky Way shots. Here is open cluster NGC 6940 using the Antares 0.7x focal reducer.

 

That reducer is one of my favorite NV accessories, yet I don't have many images using it. Just a matter of target framing and random chance really. It gives very sharp performance. Unfortunately, this particular image had some camera tilt, as you can see by comparing the Left and Right edges of the image <sigh>.

How does this compare with a Televue converter?

 

Thanks



#242 Jeff Morgan

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Posted 17 February 2021 - 02:40 PM

How does this compare with a Televue converter?

 

Thanks

 

They are complimentary, not competitive. Much like a 31 Nagler does not replace a 17 Nagler. Both are useful since they deliver different image scale (magnification).

 

The thing to remember when using a device with a given telescope (be it a camera or NVD) is that brightness and magnification are inversely related. If you want more of one, you trade some of the other.

 

The Tele Vue converter gives you essentially the image scale of a 67mm eyepiece. And maximum brightness.

 

The focal reducer (in prime focus configuration) is equivalent to a 40mm eyepiece (27mm of the NVD divided by the reduction factor of 0.7x). Less brightness, but more magnification.

 

If your NVD is not capable of prime focus configuration, then a 40mm Plossl used afocally would deliver similar results as a 0.7x reducer.

 

Some people (Gavster IIRC) have used the Tele Vue 55 Plossl afocally with a 0.7x reducer. A search of the forum should turn up those posts.


Edited by Jeff Morgan, 17 February 2021 - 02:41 PM.


#243 Deadlake

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Posted 17 February 2021 - 03:54 PM

They are complimentary, not competitive. Much like a 31 Nagler does not replace a 17 Nagler. Both are useful since they deliver different image scale (magnification).

 

The thing to remember when using a device with a given telescope (be it a camera or NVD) is that brightness and magnification are inversely related. If you want more of one, you trade some of the other.

 

The Tele Vue converter gives you essentially the image scale of a 67mm eyepiece. And maximum brightness.

 

The focal reducer (in prime focus configuration) is equivalent to a 40mm eyepiece (27mm of the NVD divided by the reduction factor of 0.7x). Less brightness, but more magnification.

 

If your NVD is not capable of prime focus configuration, then a 40mm Plossl used afocally would deliver similar results as a 0.7x reducer.

 

Some people (Gavster IIRC) have used the Tele Vue 55 Plossl afocally with a 0.7x reducer. A search of the forum should turn up those posts.

Thanks for that, I've read Gavster used a tele compressor with his C11. My next question was using the a Tele Vue 55 Plössl with a reducer as well and Mewlon together.  




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