Topics

locked Pluto blink comparator astrophotography #EXOS2 #astrophotography #VIDEO


Mike Leemhuis
 

I decided last week to try to photograph Pluto since it was the only "planet" that I hadn't photographed yet with my EXOS-2.  So I used my plate solver to aim my ES 102CF and took about 40 - 1 minute exposures.  After stacking the pictures I soon realized that Pluto must either be too small or it must look like just another star because I couldn't find it in the hundreds of stars in the picture.  So I decided to repeat the process the following day and then compare the pictures to see what moves.  That would have to be Pluto.  My friend who is the head of the Astronomy club here in Lexington told me that's how Clyde Tombaugh found Pluto in 1930 although he used a mechanical blink comparator contraption to look for movement.  So I did that the modern way by using Affinity Photo to align both pictures and then made a short movie switching back and forth between the them.  I'll attach a link to the video here:
https://www.dropbox.com/s/unhlttvs1ncha10/Pluto%20Blink%20Comparator.mov?dl=0
You can play this video in a loop and replicate with today's technology what Clyde did back in 1930. Pluto pops out if you look closely.  This would be a terrific science experiment for a high school student if you ever need an idea!

Mike

--
Location: Nicholasville, KY
Mount: Explore Scientific Exos-2
Scope: Explore Scientific ED102CF, Orion 60mm guidescope
Camera: QHY163C and QHY5L-ii
Filter: Optolong L-eNhance 2"
Software: ASCOM, PHD2, CDC, Stellarium, Sharpcap Pro, NINA, Deep Sky Stacker, Affinity Photo, Lightroom
Computer:  ASRock X570 Steel Legend, AMD Ryzen 7 3700X 8-Core Processor, 3600Mhz
Extras:  Lots of 3D printed parts I designed for improved usability


Wes Mcdonald
 

Mike

Can’t see it.  Can you make a still with it circled?

And I have this question:

If Mickey is a mouse
And Donald is a duck
And Pluto is a dog.....

What is Goofy?

Wes

--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


jrichard333 <jrichard333@hotmail.com>
 

Goofy is a groupie.


JR




-------- Original Message --------
Subject: Re: [ESPMC-Eight] Pluto blink comparator astrophotography #astrophotography #EXOS2 #VIDEO
From: Wes Mcdonald
To: MAIN@espmc-eight.groups.io
CC:

Mike

Can’t see it.  Can you make a still with it circled?

And I have this question:

If Mickey is a mouse
And Donald is a duck
And Pluto is a dog.....

What is Goofy?

Wes

--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Lloyd Simons
 

Lower right
--
Lloyd Simons
Mattawan, MI
Telescopes: Astrotech AT72ED II, Orion 8" Dobsonian, Tectron 15" Dobsonian, Celestron Super Polaris C8
Imaging Camera: Canon T3i
Guide Camera: QHY5L-IIM on a 60mm F4 Guidescope
Mounts: iExos-100 PMC-8, Vixen Super Polaris
Mount Control: KODLIX gn41 mini PC, Explorestars on a Lenovo Tab 2 A10-70F Android 6.0
Software: N.I.N.A. for imaging, PHD2 for guiding, Sharpcap for PA, Cartes du Ciel, PixInsight


Mike Leemhuis
 

Here are the files Wes.  I also circled the area to make it easier to find.  It sure is small!
Mike
--
Location: Nicholasville, KY
Mount: Explore Scientific Exos-2
Scope: Explore Scientific ED102CF, Orion 60mm guidescope
Camera: QHY163C and QHY5L-ii
Filter: Optolong L-eNhance 2"
Software: ASCOM, PHD2, CDC, Stellarium, Sharpcap Pro, NINA, Deep Sky Stacker, Affinity Photo, Lightroom
Computer:  ASRock X570 Steel Legend, AMD Ryzen 7 3700X 8-Core Processor, 3600Mhz
Extras:  Lots of 3D printed parts I designed for improved usability


 

Got it.  Well done, Mike! :-)

The circle is dull red, tough to spot at default resolution on my laptop panel.  Blow the circled gif up and it's easier to spot. 
Note the star positions and then go back to the video.   Pluto just bounces back and forth as he blinks it.  :-)    


On Mon, Aug 10, 2020, at 19:02, Mike Leemhuis wrote:
Here are the files Wes.  I also circled the area to make it easier to find.  It sure is small!
Mike
--
Location: Nicholasville, KY
Mount: Explore Scientific Exos-2
Scope: Explore Scientific ED102CF, Orion 60mm guidescope
Camera: QHY163C and QHY5L-ii
Filter: Optolong L-eNhance 2"
Software: ASCOM, PHD2, CDC, Stellarium, Sharpcap Pro, NINA, Deep Sky Stacker, Affinity Photo, Lightroom
Computer:  ASRock X570 Steel Legend, AMD Ryzen 7 3700X 8-Core Processor, 3600Mhz
Extras:  Lots of 3D printed parts I designed for improved usability

Attachments:
  • 8-6 Pluto Cropped.gif
  • 8-7 Pluto Cropped.gif
  • 8-7 Pluto Cropped Circled 2.gif


--
Mounts: ES PMC-8 EXOS2
Scopes: SV 102EDT, ZWO 60/280 Guide
Cameras:  Nikon D5300, Altair GPCAM2 290M
Software: ASCOM, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer:  Thinkpad x230, Win7Pro/64


Mike Leemhuis
 

Sorry about the thin line.  It doesn't show up on smaller displays.  Here is a thick red circle.

Mike


On Mon, Aug 10, 2020 at 7:52 PM Robert Hoskin <devonshire@...> wrote:
Got it.  Well done, Mike! :-)

The circle is dull red, tough to spot at default resolution on my laptop panel.  Blow the circled gif up and it's easier to spot. 
Note the star positions and then go back to the video.   Pluto just bounces back and forth as he blinks it.  :-)    


On Mon, Aug 10, 2020, at 19:02, Mike Leemhuis wrote:
Here are the files Wes.  I also circled the area to make it easier to find.  It sure is small!
Mike
--
Location: Nicholasville, KY
Mount: Explore Scientific Exos-2
Scope: Explore Scientific ED102CF, Orion 60mm guidescope
Camera: QHY163C and QHY5L-ii
Filter: Optolong L-eNhance 2"
Software: ASCOM, PHD2, CDC, Stellarium, Sharpcap Pro, NINA, Deep Sky Stacker, Affinity Photo, Lightroom
Computer:  ASRock X570 Steel Legend, AMD Ryzen 7 3700X 8-Core Processor, 3600Mhz
Extras:  Lots of 3D printed parts I designed for improved usability

Attachments:
  • 8-6 Pluto Cropped.gif
  • 8-7 Pluto Cropped.gif
  • 8-7 Pluto Cropped Circled 2.gif


--
Mounts: ES PMC-8 EXOS2
Scopes: SV 102EDT, ZWO 60/280 Guide
Cameras:  Nikon D5300, Altair GPCAM2 290M
Software: ASCOM, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer:  Thinkpad x230, Win7Pro/64


--
Location: Nicholasville, KY
Mount: Explore Scientific Exos-2
Scope: Explore Scientific ED102CF, Orion 60mm guidescope
Camera: QHY163C and QHY5L-ii
Filter: Optolong L-eNhance 2"
Software: ASCOM, PHD2, CDC, Stellarium, Sharpcap Pro, NINA, Deep Sky Stacker, Affinity Photo, Lightroom
Computer:  ASRock X570 Steel Legend, AMD Ryzen 7 3700X 8-Core Processor, 3600Mhz
Extras:  Lots of 3D printed parts I designed for improved usability


Shailendra Sharma <sshailendrasharma@...>
 

How are you balancing your dec? Mine is near on impossible? Got a pic of how your cables are rooted? And how do you offset the balance due to the dec motor assembly?

Cheers


From: MAIN@ESPMC-Eight.groups.io <MAIN@ESPMC-Eight.groups.io> on behalf of Mike Leemhuis <skislalom1@...>
Sent: Monday, August 10, 2020 7:59:03 PM
To: MAIN@ESPMC-Eight.groups.io <MAIN@ESPMC-Eight.groups.io>
Subject: [ESPMC-Eight] Pluto blink comparator astrophotography #astrophotography #EXOS2 #VIDEO
 
I decided last week to try to photograph Pluto since it was the only "planet" that I hadn't photographed yet with my EXOS-2.  So I used my plate solver to aim my ES 102CF and took about 40 - 1 minute exposures.  After stacking the pictures I soon realized that Pluto must either be too small or it must look like just another star because I couldn't find it in the hundreds of stars in the picture.  So I decided to repeat the process the following day and then compare the pictures to see what moves.  That would have to be Pluto.  My friend who is the head of the Astronomy club here in Lexington told me that's how Clyde Tombaugh found Pluto in 1930 although he used a mechanical blink comparator contraption to look for movement.  So I did that the modern way by using Affinity Photo to align both pictures and then made a short movie switching back and forth between the them.  I'll attach a link to the video here:
https://www.dropbox.com/s/unhlttvs1ncha10/Pluto%20Blink%20Comparator.mov?dl=0
You can play this video in a loop and replicate with today's technology what Clyde did back in 1930. Pluto pops out if you look closely.  This would be a terrific science experiment for a high school student if you ever need an idea!

Mike

--
Location: Nicholasville, KY
Mount: Explore Scientific Exos-2
Scope: Explore Scientific ED102CF, Orion 60mm guidescope
Camera: QHY163C and QHY5L-ii
Filter: Optolong L-eNhance 2"
Software: ASCOM, PHD2, CDC, Stellarium, Sharpcap Pro, NINA, Deep Sky Stacker, Affinity Photo, Lightroom
Computer:  ASRock X570 Steel Legend, AMD Ryzen 7 3700X 8-Core Processor, 3600Mhz
Extras:  Lots of 3D printed parts I designed for improved usability


Timothy Myers
 

I don't feel so bad if Wes couldn't see it, after reading the hint, Lower Right I did see an object moving back and forth from left to right, was that it?
--
Tim Myers

Telescopes:           Celestron 4SE, Celestron 8SE, SkyWatcher 100ED Pro
Mounts:                 4-5 SE, 6-8SE, EXOS-2GT with PMC-Eight
Cameras:              ASI1600MC Imaging Camera, Cooled, ASI120 Guide Camera
Focuser:               ZWO EAF
Scope Mini PC:    Topton Pentium
Laptop:                Lenovo
Software:             CDC, SharpCap Pro, NINA, PHD2


Wes Mcdonald
 

I believe so. pops in and out.  really something.  

Wes.


On Sat, Aug 15, 2020 at 3:47 PM Timothy Myers <tim_s_myers@...> wrote:
I don't feel so bad if Wes couldn't see it, after reading the hint, Lower Right I did see an object moving back and forth from left to right, was that it?
--
Tim Myers

Telescopes:           Celestron 4SE, Celestron 8SE, SkyWatcher 100ED Pro
Mounts:                 4-5 SE, 6-8SE, EXOS-2GT with PMC-Eight
Cameras:              ASI1600MC Imaging Camera, Cooled, ASI120 Guide Camera
Focuser:               ZWO EAF
Scope Mini PC:    Topton Pentium
Laptop:                Lenovo
Software:             CDC, SharpCap Pro, NINA, PHD2


--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Mike Leemhuis
 

Yes, it’s at the lower right. I should try to find a way to blink at a faster rate. Might be easier to see. 


Mike
--
Location: Nicholasville, KY
Mount: Explore Scientific Exos-2
Scope: Explore Scientific ED102CF, Orion 60mm guidescope
Camera: QHY163C and QHY5L-ii
Filter: Optolong L-eNhance 2"
Software: ASCOM, PHD2, CDC, Stellarium, Sharpcap Pro, NINA, Deep Sky Stacker, Affinity Photo, Lightroom
Computer:  ASRock X570 Steel Legend, AMD Ryzen 7 3700X 8-Core Processor, 3600Mhz
Extras:  Lots of 3D printed parts I designed for improved usability


Wes Mcdonald
 

Shailendra 

This is a good question

1.  The larger the aperture the more photons you collect per unit time 

2.  The shorter the focal length the larger fov of a fixed pixel size in the imaging camera

3.  The larger the aperture the smaller the diffraction limit of the scope which governs the smallest resolution.  Small aperture of 80mm has about 1.7” resolution limit.  A 127mm has about 1.1”.  A 152mm has .92”.  Some image with a 51mm which as a resolution limit of 2.7”. Note seeing limit is somewhere between 1” and 2” most places, seldom as low as 1”

4.  We want to match the effective pixel size to the overall seeing of the atmosphere.  Also pixel size (in arc seconds) should be matched to your guiding performance.  In general we presume guiding has small errors and thus adjust our imaging train to optimize the pixel size to our atmosphere seeing.  There is no need to sample the image more than twice as good as the seeing allows.  Note I am assuming  we have a scope for which the diffraction limit is about the same or smaller than the atmospheric seeing 

5.  Sooooo.  We use a big aperture to shorten our exposures times.  This  relieves pressure for long guiding performance.  It is also important if you are using narrowband filters to reduce those exposure times.  We use a focal reducer to change the focal length to adjust the image scale of a camera pixel to better match it to the seeing and diffraction limit of the scope.  In practice if you have about a 120mm or larger aperture your diffraction limit is not a concern.  ES 127 is perfect.

6.  If the scope has a long focal length, the pixel scale is small.  This is a waste since your image resolution is limited by the seeing. It also limits your overall field of view unnecessarily.  Thus for long focal length scopes we use focal reducers to optimize both our field of view and pixel scale to seeing limits.

7.  Field flateners don’t do much to the resolution, but rather it corrects distortion at the edges of the lens field of view.  Often flateners are included in the optics of focal reducers.  

So these points address your question and add up to a set of parameters you have at your disposal to tune your image train to achieve your goals. Understand these considerations are relative to imaging deep space objects.  Planetary imaging has a different set of considerations which would make another email.

In general I feel the sweet spot for imaging is about 900 mm fl.  For DSLR cameras this yields pixel scales at about 1”.  There is no reason to go to longer focal lengths.  At 127mm you get enough photons to be able to expose at relatively low gain (iso 320) for 3 or 4 minutes for your subs and take nice images for many many DSO.  If you can get a larger aperture with a focal length in this range (with or without a focal reducer) and it is light enough for your mount then larger is good.  The exos2 ends up being able to handle a wide range of apertures as evidenced by the forum equipment lists.


For visual, aperture is king.  Your eye needs photons.

Wes   

--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Jerry Hubbell - Explore Scientific VP Engineering
 

On Sun, Aug 16, 2020 at 04:16 AM, Shailendra Sharma wrote:
Looking at a new scope atm. But what I don't get is this;

If you buy a big scope and add a field flattner, or reducer what is the benefit of droping focal length? Wouldn't you just buy a smaller scope? I'm 100% sure I have missed something lol! Thanks
Hi Shailendra,

If you don't mind, please post this as a new topic. This is off topic for this message thread.
 
--
Jerry Hubbell
Vice President of Engineering

Explore Scientific, LLC.
jrh at explorescientific.com

www.explorescientificusa.com
1010 S. 48th Street
Springdale, AR 72762
1-866-252-3811

Author: Scientific Astrophotography: How Amateurs Can Generate and Use Professional Imaging Data
             Remote Observatories for Amateur Astronomers: Using High-Powered Telescopes From Home


Mark Slade Remote Observatory (MSRO) IAU MPC W54 Equipment
Wilderness, VA
Mounts
: ES PMC-Eight G11 + Telescope Drive Master (TDM)
Scopes: ES 165 FPL-53 ED APO CF, ES 102 FCD100 ED APO CF
Cameras:  QHY174M-GPS + FW, QHY163C
Misc: 3-inch 0.7x Focal Reducer Field Flattener, Filters: Luminance,
Red, V-band Photometric, Diffuser, 200 lpmm Spectral Grating

Software: MaxIm DL 6, Cartes du Ciel, Astrometrica, AstroImageJ, AutoStakkert!