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Anyone can share an image of Beta Monocerotis

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#1 Yourjones

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Posted 11 December 2019 - 09:05 AM

Hi

 

Have you managed to picture Beta Mon with its B and C components resolved? Would you mind also sharing one single unstacked image of it? I wonder the difference.

 

The moon is high and bright here, but I guess its effect on shooting doubles is not so huge. 

 

Thanks



#2 ssmith

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Posted 11 December 2019 - 11:27 AM

Here is a crop of a single jpg image of Beta Mon.

TSA120 Exposure 1/10 sec ISO 800

beta mon 120mm 2-16-17 143e crop.jpg

I have found that the full moon can often be helpful in resolving bright close doubles. The full moon only really becomes a problem when it reduces the limiting magnitude to such an extent that one or more of the components become unviewable.

Edited by ssmith, 11 December 2019 - 11:54 AM.

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#3 dmdouglass

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Posted 11 December 2019 - 11:53 AM

Well, as usual, Steve captured it beautifully !!

I captured it back in Jan, while working on my list of Herschel Doubles.

This target has two Herschel designations...  H-II-17, and H-I-10.

 

Here is what i got... exposure time was 15 sec/frame.  If i were to do it again, i would start about 5 sec/frame, and work my way DOWN, trying to get better separation.  

.

H-2-017-DS-20190108.jpg


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#4 Yourjones

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Posted 11 December 2019 - 08:35 PM

Here is a crop of a single jpg image of Beta Mon.

TSA120 Exposure 1/10 sec ISO 800

attachicon.gif beta mon 120mm 2-16-17 143e crop.jpg

I have found that the full moon can often be helpful in resolving bright close doubles. The full moon only really becomes a problem when it reduces the limiting magnitude to such an extent that one or more of the components become unviewable.

Really great resolution, thanks for sharing!

 

Do you think a normal 80mm refractor (Celestron 80EQ) would be better than the Newtonian (150/750) for double star attempts? My small refractor has been put under the bed ever since the Newtonian arrived. 



#5 Yourjones

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Posted 11 December 2019 - 08:40 PM

Well, as usual, Steve captured it beautifully !!

I captured it back in Jan, while working on my list of Herschel Doubles.

This target has two Herschel designations...  H-II-17, and H-I-10.

 

Here is what i got... exposure time was 15 sec/frame.  If i were to do it again, i would start about 5 sec/frame, and work my way DOWN, trying to get better separation.  

.

attachicon.gif H-2-017-DS-20190108.jpg

Thanks David for such informative response. I, a noob here, am worried if the shutter has been too slow? Shall we set higher or lower shutter speed when trying to resolve double stars. I understand the ISO should go the way reverse as you adjust the shutter. 



#6 dmdouglass

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Posted 11 December 2019 - 09:42 PM

Thanks David for such informative response. I, a noob here, am worried if the shutter has been too slow? Shall we set higher or lower shutter speed when trying to resolve double stars. I understand the ISO should go the way reverse as you adjust the shutter. 

Unfortunately, i am NOT a DSLR guy... my cameras are astro cameras...

BUT.... Steve (above) IS a DSLR guy.  He can probably address this.



#7 ssmith

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Posted 11 December 2019 - 09:44 PM

YourJones -

The best advice I can give is to let your previous experiences guide you. I took a look at your gallery in your profile and you had images of Castor and Delta Gem posted.

Both these systems have separations of +5” and with Beta Mon You will be going down to half that value (2.6”). I have always mentally used
5” as a dividing line when I consider imaging a system. Above that value seeing conditions don’t matter much to me and I can image at prime focus. Below that value seeing becomes more important and I have to consider whether to use a Barlow or eyepiece projection to get an adequate image scale. You need to figure out that magic number for your particular setup.

Looking at your images, if you do exactly what you did before but cut the separation in half what do you end up with? I would say you need to increase the image scale(add magnification) and sharpen the image (your star images look soft) which could be due to poor focus or unsteady seeing or poor collimation. With close pairs you have to cut down exposure times to freeze the seeing in order to resolve the individual stars while boosting the ISO to collect enough light.

Edited by ssmith, 11 December 2019 - 09:59 PM.


#8 Yourjones

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Posted 12 December 2019 - 01:09 AM

YourJones -

The best advice I can give is to let your previous experiences guide you. I took a look at your gallery in your profile and you had images of Castor and Delta Gem posted.

Both these systems have separations of +5” and with Beta Mon You will be going down to half that value (2.6”). I have always mentally used
5” as a dividing line when I consider imaging a system. Above that value seeing conditions don’t matter much to me and I can image at prime focus. Below that value seeing becomes more important and I have to consider whether to use a Barlow or eyepiece projection to get an adequate image scale. You need to figure out that magic number for your particular setup.

Looking at your images, if you do exactly what you did before but cut the separation in half what do you end up with? I would say you need to increase the image scale(add magnification) and sharpen the image (your star images look soft) which could be due to poor focus or unsteady seeing or poor collimation. With close pairs you have to cut down exposure times to freeze the seeing in order to resolve the individual stars while boosting the ISO to collect enough light.

Thank you for your suggestions! While I was sure I was well collimated, it wasn't clear if the focus has been done to standard. And the seeing condition is not very friendly. I still haven't figured out the best settings of everything for my system. I reckon I probably should start stacking images soon in order to "work out" better doubles. Thanks again! 



#9 ssmith

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Posted 12 December 2019 - 10:11 AM

Stacking isn't a panacea when it comes to double stars and it wont make up for any deficiencies in your system.  It is a well known adage when stacking images that your final result will only be as good as the quality of your subs.

 

Stacking will only smooth out irregularities and it wont make stars magically appear.  I did a 3-d plot of your Wasat image and it illustrates what I meant by your images being soft.  The centroids of your stars are not well defined so stacking may not gain you much.  I also did a simple sharpening of your image and a contrast boost in photoshop which helped a bit.

 

gallery_320686_12286_69146.jpeg

 

Wassat_3dplot.jpg

 

Wassat Sharpen.jpg


Edited by ssmith, 12 December 2019 - 12:49 PM.

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#10 Yourjones

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Posted 12 December 2019 - 10:10 PM

Thanks Steve! I see your point from your efforts trying to modify my image. Now I seriously doubt if my focus was not good enough. I carved a Mahtinov Mask last night using a template downloaded from the Internet. I am going to give it another try when the atmospheric conditions are better. 

 

However, I am reluctant to agree with SkySafari's description about Wasat:

 

 "Tucked next to it is a magnitude 8.1 companion which is clearly visible in a small telescope."



#11 ssmith

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Posted 13 December 2019 - 12:31 AM

I admire your commitment to making your own mask as they are relatively inexpensive. They are a great focusing aid. If you haven’t used one before you may find that it may dim the view enough to make it difficult to read the pattern but don’t let this discourage you. Just take a photo with the mask in-place and then examine the photo to make fine adjustments until you get it just right.

I would have to agree with you that Del Gem isn't all that easy in a small scope considering the difference in magnitudes.

Here is a photo of mine taken with a 120mm refractor.

Del Gem 120mm 2-26-16 073e.jpg


Edited by ssmith, 13 December 2019 - 08:09 AM.

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#12 Yourjones

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Posted 13 December 2019 - 03:04 AM

Here is a photo of mine taken with a 120mm refractor.

attachicon.gifdel gem 120mm 2-26-16 073e.jpg

I'm totally astonished to see this! And I can't but wondering what was there in my picture! 

 

1. Did you add the DSLR's own magnification to achieve this?

2. What have  the eyepiece and Barlow been for this work? I assume they must have been a high power combination.

3. And lastly, is it true or rumor that refractors are better at resolving double?

 

Thank you so much!



#13 ssmith

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Posted 13 December 2019 - 07:52 AM

The image was taken at prime focus so there was no eyepiece projection or barlow used.  When I take my photos I save the images in both camera raw format and jpg.  Below are copies of the of the original raw and jpg files (reduced to fit CN size limitations).  The raw file has been stretched and shows the large amount of data recorded for such a short exposure time. 

 

The raw photo clearly shows the FOV and I have also included the plate-solve parameters for the photos.

The double star photo posted above was cropped from the jpg photo below.

 

Referentiation matrix (world[ra,dec] = matrix * image[x,y]):
-2.22683143e-04  +7.67530150e-05  +3.83429401e-01
-7.67315076e-05  -2.22705569e-04  +5.64611195e-01
WCS transformation ....... Linear
Projection ............... Gnomonic
Projection origin ........ [2320.160140 1735.842582] px -> [RA:  7 20 02.108  Dec: +21 58 31.26]
Resolution ............... 0.848 arcsec/px
Rotation ................. -19.018 deg
Observation start time ... 2016-02-27 04:05:32 UTC
Observation end time ..... 2016-02-27 04:05:47 UTC
Focal distance ........... 681.09 mm
Pixel size ............... 2.80 um
Field of view ............ 1d 5' 34.6" x 49' 4.1"
Image center ............. RA:  7 20 02.120  Dec: +21 58 31.18
Image bounds:
   top-left .............. RA:  7 21 41.735  Dec: +22 32 21.88
   top-right ............. RA:  7 17 13.693  Dec: +22 10 56.73
   bottom-left ........... RA:  7 22 50.053  Dec: +21 45 54.93
   bottom-right .......... RA:  7 18 23.295  Dec: +21 24 36.76

 

Delta Gem_120mm_2_26_16_088_G jpg convert.jpg

 

120mm 2-26-16 073e resize.jpg


Edited by ssmith, 13 December 2019 - 08:08 AM.

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#14 ssmith

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Posted 13 December 2019 - 08:28 AM

The image was taken at prime focus so there was no eyepiece projection or barlow used.  When I take my photos I save the images in both camera raw format and jpg.  Below are copies of the of the original raw and jpg files (reduced to fit CN size limitations).

 

The raw photo clearly shows the FOV and I have also included the plate-solve parameters for the photos.

The double star photo posted above was cropped from the jpg photo below.

 

F:/2016 ASTRO PHOTOS/Astro 2-26-16/55 Gem  Other/120mm 2-26-16 074e.ORF
Reading metadata: done

Camera ........... Olympus E-PL5
Timestamp ........ 2016-02-27T04:03:13Z
Exposure ......... 1/2s
ISO speed ........ 200
CFA pattern ...... Bayer RGGB
Raw dimensions ... w=4640 h=3472
Image geometry ... x=0 y=0 w=4640 h=3472

 

Referentiation matrix (world[ra,dec] = matrix * image[x,y]):
-2.22683143e-04  +7.67530150e-05  +3.83429401e-01
-7.67315076e-05  -2.22705569e-04  +5.64611195e-01
WCS transformation ....... Linear
Projection ............... Gnomonic
Projection origin ........ [2320.160140 1735.842582] px -> [RA:  7 20 02.108  Dec: +21 58 31.26]
Resolution ............... 0.848 arcsec/px
Rotation ................. -19.018 deg
Observation start time ... 2016-02-27 04:05:32 UTC
Observation end time ..... 2016-02-27 04:05:47 UTC
Focal distance ........... 681.09 mm
Pixel size ............... 2.80 um
Field of view ............ 1d 5' 34.6" x 49' 4.1"
Image center ............. RA:  7 20 02.120  Dec: +21 58 31.18
Image bounds:
   top-left .............. RA:  7 21 41.735  Dec: +22 32 21.88
   top-right ............. RA:  7 17 13.693  Dec: +22 10 56.73
   bottom-left ........... RA:  7 22 50.053  Dec: +21 45 54.93
   bottom-right .......... RA:  7 18 23.295  Dec: +21 24 36.76

 

Delta Gem_120mm_2_26_16_088_G jpg convert.jpg

 

120mm 2-26-16 073e resize.jpg


Edited by ssmith, 13 December 2019 - 08:38 PM.

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#15 Yourjones

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Posted 13 December 2019 - 06:18 PM

The image was taken at prime focus so there was no eyepiece projection or barlow used.  when I take my photos I save the images in both camera raw format and jpg. 

 

Thank you Steve for the instruction on shooting double stars. I actually have used a lot of eyepieces and other accessories to achieve more magnified image. The problem I didn't even realize that I was having is that I didn't use prime focus, and I didn't save the raw images with my Nikon D5600. I should have known that my setup supports about 1 at second per pixel. I'll try it this time. 

 

By the way, I visited your site and saw so many fabulous images of doubles stars delicately grouped by constellation. Currently, I am admiring the Cancer constellation, and hopefully I could get some better resolved doubles soon from that part of the sky. 



#16 ssmith

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Posted 13 December 2019 - 08:36 PM

The problem I didn't even realize that I was having is that I didn't use prime focus, and I didn't save the raw images with my Nikon D5600. I should have known that my setup supports about 1 at second per pixel. I'll try it this time. 

I don't want you to get the wrong idea - I wasn't saying that prime focus is the best or only way to do double star photography, I was merely giving examples as to how I shoot them and explain the limits of my imaging system. 

 

I do believe that keeping as much glass out of the optical train as possible will result in sharper images (less likely to introduce optical aberrations) and allow for shorter exposure times (lower f number) if the separations and magnitudes of the subject allow it.

 

You didn't give any details to the optical train you used on your photos so perhaps you can go into a bit more detail as to the equipment (scope, barlows?, eyepieces?)  used.


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#17 Yourjones

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Posted 14 December 2019 - 08:38 AM

You didn't give any details to the optical train you used on your photos so perhaps you can go into a bit more detail as to the equipment (scope, barlows?, eyepieces?)  used.

No, I didn't get it wrong. I'll have to try the prime focusing strategy and work on the raw picture, now that I think I'm closer to fully understanding"arcsecond per pixel". 

 

My optical train has consisted of the following, in order of how they were connected:

 

DSLR

T ring

Extension tube with a 10mm eyepiece inside

The extension tube-1.25 adaptor

5x barlow

Focuser

 

The 10mm eyepiece is currently the most powerful one able to be inserted in the extension tube. I do have a poorly-built 4mm one, which is out of the question. 

 

It's cloudy tonight here, but I can't wait giving prime focusing a try soon as it is clear. 



#18 ssmith

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Posted 14 December 2019 - 09:13 AM

Are you saying that you used the Barlow in conjunction with the 10mm eyepiece to take the photo of Wasat? If that is the case then that goes a long way to explain why your image is so fuzzy.

If you were using your 750/150 Newtonian that would mean you were at 375x.
The most I ever use on my system is a 2.5x powermate which gives me ~100x.

Note that magnification really isn’t applicable when discussing imaging. We should really be comparing FOV which takes the camera sensor properties into account.

Edited by ssmith, 14 December 2019 - 09:41 AM.


#19 Yourjones

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Posted 14 December 2019 - 09:23 PM

Note that magnification really isn’t applicable when discussing imaging. We should really be comparing FOV which takes the camera sensor properties into account.

I understand. Thank you!
 

I'm considering to get rid of the negative effect caused by the multiple lenses by applying prime focus now. But I guess the shutter speed and the ISO are also a big science here. I'll just have to play with it for a while and decide the best parameters for my combination. 



#20 fred1871

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Posted 16 December 2019 - 01:52 AM

The Televue Powermate amplifiers of focal length (similar to a Barlow, different optical formula)  are the best I've come across. I discussed them with the noted planetary imager Anthony Wesley a little while back and he said they were the best he'd found for getting all colours to the same focus, very important for high resolution planetary imaging. Ditto for doubles.

 

Powermates come with various powers, amplifying the focal length up to up 5x : so your 750mm focal length Newtonian could become 1500mm (2x) up to 3750mm (5x) for imaging. Deciding what to use involves matching the telescope resolution to the scale, with matching the pixel size to desired resolution an important factor important as Steve has indicated above. He's a good one to learn from as his exceptional quality images show.

 

And, no, I have no connection with Televue. smile.gif


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#21 Yourjones

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Posted 17 December 2019 - 07:57 AM

The Televue Powermate amplifiers of focal length (similar to a Barlow, different optical formula)  are the best I've come across. I discussed them with the noted planetary imager Anthony Wesley a little while back and he said they were the best he'd found for getting all colours to the same focus, very important for high resolution planetary imaging. Ditto for doubles.

 

Powermates come with various powers, amplifying the focal length up to up 5x : so your 750mm focal length Newtonian could become 1500mm (2x) up to 3750mm (5x) for imaging. Deciding what to use involves matching the telescope resolution to the scale, with matching the pixel size to desired resolution an important factor important as Steve has indicated above. He's a good one to learn from as his exceptional quality images show.

 

And, no, I have no connection with Televue. smile.gif

Hi Fred
 

Thank you for the recommendation of the Powermate! I'll surely give it a try. Because I have a 5x Barlow already, I consider having a less powerful Powermate to start with. 
 

And no, you have no connection with Televue




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