visual art Planets, Astrophotography, and UV/IR Photography

[Phosphor 11,529]

It's been a little while since I posted anything in this thread. Pretty much the whole month of December was rainy. It feels good to be back in business again!  

To help obtain more exposures, I purchased an intervalometer. Basically, it's a digital timer that also operates the camera for you. It worked wonderfully last night. I set the parameters, pressed start, and went inside to watch the football game.  

Here's my 2nd attempt on the Orion Nebula: (details on lower left corner)

[Phosphor 11,529]

I think the crescent phase has to be my favorite. After sunset, the night time portion of the Moon is illuminated with reflected light from Earth, known as Earthshine. It's easily visible to the naked eye and can be captured with a camera and zoom lens. I used my 90mm refractor, since my dslr was already mounted to it.

Last image is my 3rd attempt on the Flame and Horsehead Nebula. Enjoy!  

[Phosphor 11,529]

The 2019 Total Lunar Eclipse.  

Images taken with Celestron C8 and Sony Alpha A55V dslr (modded)

The rest of the images. I also have a couple Near IR shots.

[Phosphor 11,529]

The Moon appears red during a total eclipse due to atmospheric refraction of light. Wavelengths shorter than red are scattered away, but if we could see in the Near IR spectrum, the Moon would appear almost the same during a total eclipse.

1st image is in visible light. 

2nd image is in Near IR. Both images were taken at the maximum eclipse and have the same camera settings.

[Phosphor 11,529]

Jupiter and Venus  

Both planets are close to each other in the sky and can be seen shining brightly shortly before sunrise. I had to use lower magnification on both due to atmospheric turbulence.  

[Phosphor 11,529]

It's been a while since I posted anything in this thread. Time to fix that. 

First three images are a pair of safety glasses in UV and visible light. I'm not too surprised by the UV photos since polycarbonate absorbs it. Still pretty neat to see it, tho.

The chapstick in the last two photos claims to have an SPF of 15, so I put it to the test. It does the job..  

 

[Odyssey 5,716]

Where do you usually go for when you look at stars and planets? I found a spot outside my town where light pollution is completely free so I can do some great stargazing from there. Do you go somewhere for that or just stick at your home?

[Phosphor 11,529]

12 hours ago, Odyssey said:

 I found a spot outside my town where light pollution is completely free

Oooo, I'm jealous! 

I setup in my backyard, usually on the back patio. I have class 4 skies out here, so I have no trouble seeing the Milky Way and such. I have a meter that measures the sky brightness. On a typical night I'll measure 21.00 mag/arcsec^2

[Phosphor 11,529]

Jupiter will be considerably lower in altitude compared to a couple years ago. That means I will have to look thru more atmosphere, which degrades image quality. Regardless, it's good to see our gas giant neighbor again.  

Next image is M51, also known as the Whirlpool Galaxy. This was my first time to image it and was able to do it with my Celestron C8. Normally I would use a short refractor, but its magnification was a bit too low for this target. Astrophotography with a C8 is tough due to its weight and long focal length. With careful adjustment of the mount's counterweights, I was able to find that sweet spot and balance the telescope. 

More to come as the summer sky approaches!  

[Phosphor 11,529]

Enjoy some White Azaleas in UV and Near Infrared light 

I've always wondered if the colors I get from my camera are real in the UV spectrum. Color and light outside the visible spectrum is quite fascinating to me.  I've tested my eyes in the past and can see down to 365nm, when looking thru a UV filter. Maybe I should look thru it on a bright sunny day and see what the flowers look like!  

Pics 1-5: Ultraviolet

Pic 6: Visible

Pics 7-8: Near Infrared

[Phosphor 11,529]

A simple, yet fun experiment to see the effect wavelength has on resolution. It's widely known that decreasing wavelength increases resolution. Also have to account for the atmosphere, since it scatters shorter wavelengths much more strongly and can cause optical dispersion.. To minimize this, I waited till the Moon was near the zenith (straight up). Turbulence is also minimal here.

 

Afterwards, I looked at some craters with a green filter. I must say, the Moon's surface looked 3D like!  

Telescope: Skywatcher 16

Camera: ZWO ASI178MM (*Monochrome camera*)

Edited April 16, 2019 by Phosphor
Specified camera type

[Barnstormer 112]

3 minutes ago, Califorum said:

It looks practically the same through all of the wavelengths.

Color-wise. Resolution-wise, not even close.

[Phosphor 11,529]

@Califorum, I forgot to mention in the post, the camera is monochrome. Will fix that. 

[Phosphor 11,529]

I woke up early Saturday morning to see Jupiter and Saturn. The forecast showed 5/5 seeing conditions for that time. It actually wasn't far off, more like 4.5/5. Telescope was already setup the night before, so it was well acclimated to the cooler temps. This is very important, else thermal currents will ruin the image. 

Jupiter's Great Red Spot looks a bit different this year with the additional cloud band wrapping around it. Saturn appears more or less the same, with the exception of its ring tilt. We're past the peak tilt from 2017, so the ring tilt will slowly decrease in angle each year. The rings will appear edge on in 2025. 

https://earthsky.org/todays-image/notice-the-tilt-in-saturns-rings

I've also included some raw video from the camera.  Enjoy everypony!  

[Phosphor 11,529]

2 hours ago, Califorum said:

Have you ever tried modifying the videos of the planets so they are less blurry?

Unfortunately, it's the atmosphere that is causing the blur. Short of leaving the atmosphere or purchasing adaptive optics (insanely expensive right now ), there isn't much I can do to make the videos better.The noise can be reduced by using a camera with an onboard cooler, but those are normally used for long exposure astrophotography, where thermal noise needs to be limited.

One thing I can do; however, is record at reduced magnification. The planet will appear smaller, but the effects of turbulence will be lessened. There's no free lunch with this method, tho. It's complicated, but in order to maximize a telescope's resolving power, the optimum focal ratio must be used. There's some math and theory involved in determining that, so I will leave it at that.  

The images come from stacking the best frames, since even under turbulent conditions, there are brief periods of stability. Hope this helps. (Oh goodness, once I get started on this topic, it's hard to stop. lol) 

[Phosphor 11,529]

It's time I give this thread some life  

Tonight was super humid, but the air was calm.  On calm nights such as this, the Celestron C8 can really shine!

Enjoy! 

[Phosphor 11,529]

Oh dear. This thread has collected quite a bit of dust.  Time to fix that.

A short video showing the appearance of objects in different wavelengths of light:  

In the first sequence, the lens is filtered with a UV/IR cut filter. This is how off-the-shelf cameras and our eyes see. The bottle is opaque and Twilight plush appears with her normal colors. The second sequence shows the removal of that filter. Since the camera's sensor had it's factory filter removed, Near IR light can be detected. The bottle appears almost transparent and the plush's colors are altered. The effect of Near IR light is quite strong. In the final sequence, a Near IR filter is placed in front of the lens. The bottle is completely transparent and the colors of the plush are gone. The reason for this is because many dyes are transparent in the Near IR region.

*An incandescent lamp was used since household LED's emit very little Near IR light

[Phosphor 11,529]

Recently, I got a chance to image Venus in UV with my Skywatcher 16 telescope. I've been wanting to compare its UV performance with my Celestron C8. The Skywatcher 16 is a reflector design, while the C8 is a Schmidt-Cassegrain (see link for more info). It is known that reflectors perform better in UV than telescopes with glass in the optical path. There are several reasons for this:

1. Glass tends to absorb UV, especially wavelengths below 365nm or so
2. Glass lenses tend to display worsening chromatic aberration with shorter wavelengths

With the C8, I can get decent UV images, but the focus is never sharp. The glass corrector plate is designed to correct spherical aberration caused by the primary mirror, but the corrector plate simply cannot do this for the entire visible spectrum, much less UV. Also, the glass corrector plate absorbs some of the UV light passing thru, dimming the image on the camera. You can see the defocus around the planet's disk. Compare that to the Skywatcher 16, the planet is well focused.

This isn't a fair comparison tho. The Skywatcher 16 has a primary mirror of 16" in diameter vs 8" for the C8, yielding 2x the resolution.

https://en.wikipedia.org/wiki/Schmidt–Cassegrain_telescope

https://en.wikipedia.org/wiki/Chromatic_aberration

Hope you enjoy reading all of that.