Astrophotography

ZWO’s ASI1600GT

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I remember in my early days my old astronomy club had a monochrome CCD camera from SBIG which was used for scientific projects. The club opened its doors to students allowing them to discover new supernovae and other cool features in the night sky involving fotometry.

Years passed by and as an amateur astronomer I’ve dealth with DSLRs for the most part of my observing sessions. While DSLRs can be suitable for using them both at day and at night, unfortunately they can’t compete with dedicated astronomy cameras.

CMOS technology has advanced more and mover over the years as well, bringing their sensors to a very competitive level vs. CCD. In a market the recipe to success is very simple and that comes with manufacturing cost. While CCD manufacturing has struggled enormously to lower its costs, CMOS has prevailed in the technology area and made itself more dominant over the years. Availability and cost efficiency are the two major factors in its success. Both sensors eventually convert light to electrons so the end result will be the same.

Thus, it brings us to the point of my blog entry here. I’ve recently acquired ZWO’s monochrome ASI1600GT. A camera that has a very effective cooling capability, high reliability, built-in filter wheel and lightweight. ZWO has done an awesome job and provided amateur astronomers with a very competitive and strong camera. I can’t wait for the California weather to offer me the chance to try it out very soon!

With my purchase I’ve also acquired a set of OIII (Oxygen), SII (Sulfur), H-alpha (Hydrogen) 7nm narrowband filters with a set of LRGB filters from SVBony as well.

Calculating Power Consumption

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When you’re planning to head out for astrophotography, one of the things in your check lists it to figure out your power consumption (or it should if you haven’t figured that out yet!). Some people rely on batteries, others again have a steady power supply from a plug in their homes/outdoor observatory sites, and finally some would rely on a power generator.

To figure out how much power your equipment consumes per hour, there’s a simply calculation method. If you know your Watt-hours and Volts (most astronomy equipment is powered by 12 Volts) to Ampere-hours you can use a simple formula to discover the amount. Supposedly your Watt-hours is 240 then we get;

Ah = \frac{Wh}{Volts} => \frac{240}{12} = 20Ah

Now, to convert how much time would that give us, create a simple list of all your equipment and how many Amperes each one of them consumes. In my case,

  • Mount (NEQ6 Pro): 4 Amp
  • Cooling Camera (ASI1600GT): 2 Amp
  • RCA Dew Heaters (1 Amp each): 2 Amp
  • Lakeside Focuser: 1 Amp
  • EAGLE Pro (Mini-PC + Power Management Unit): 1 Amp

That would give us a total of 10Ah. Supposedly I’m using a Duracell battery of 20Ah, then my power consumption would end up discharging my battery source after 2 hours (20 Ah / 10 Ah).

Instead, in my case I would then need a steady powersource for much longer than that. In average my observing sessions are no less than 3 hours (on mediocre nights) or even up to 4 or 5 hours when there are really beautiful night skies making it worthwhile to stay up longer.

A battery would be enough to just observe visually, but definetely wouldn’t take me a long way for astrophotography. And to make matters worse with batteries, they shouldn’t go below 20% of their total capacity if you want them to be long lived, or say goodbye to an expensive battery after just a few sessions!

I’ve decided that, for my own personal gain to buy a power generator that would provide me a reliable power source for many hours at end, without risking killing any expensive batteries, damage my equipment or to abandon a beautiful night sky. Additionally it gives me great independence from anything when it comes to sudden power outages, people around, or ending up running out on battery sources.

The downside is of course a solid power generator would become heavy to carry around (the one I’m looking at is 48 lbs) and the other downside is of course its loudness (~50 dB which corresponds to light rainfall) when its operating. You’ll also need a long cable to avoid having it too close to cause vibrations during your astrophotography session.

Ultimately nothing beats a steady power source offered by a wall outlet… But you can’t ask to have everything right?

Sharing the passion for astronomy and astrophotography

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July 30th, 2020 was the International Friendship Day and I had the pleasure to meet Maxx, Sunita and their friends by having our own little star party. We had a short walkthrough on the main summer constellations and the ancient Greek tales behind them (the stories behind king Lyacon, Callisto and her son Arcas, Cassiopeia, Andromeda, Medusa, Kraken and Perseus, Hercules and the serpent dragon Draco) We spoke a little bit about the constellation of Scorpio sent by goddess of hunting Artemis that bit Orion.

Planets Saturn (aka Kronos in ancient Greek mythology, son of Uranus and Gaia or Earth) and Jupiter (aka Zeus in ancient Greek mythology) were very prominent and right above the meridian, as well as the moon

Transparency: Transparent (Above Average)
Seeing: Poor 2/5
Darkness: Magnitude 5.0 (Moon altitude 26.5 degrees)
Wind: 0 – 5 mph
Humidity: 40% to 50%
Temperature: 68F to 77F degrees
Elevation: 5283 ft.

We used the cellphones and photographed the moon, Saturn and Jupiter through afocal method by aligning the cell phone cameras in the eyepiece field of view.

Niklas Henricson

Milky way

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Haven’t done the Milky way in a while and this time I’ve chosen with a Canon 50D and a Canon 35mm lens. The settings were AWB, ISO 1600 and 14 seconds of exposure by using the 500-rule (500/lens mm).

The foreground is Henry Grieb Observatory – Nyack Airport in Blue Canyon, CA. Right above the dome Saturn to the left and Jupiter to the right.

I’ve now ordered Canon’s EF-S 24mm f/2.8 STM lens which apparently is one of the top 3 Canon lenses for Milky way astrophotography to try and get some better results. The lens I was using for the image above isn’t really suitable for Milky way due to high f-ratio, making it a “slow” lens in allowing faint light coming through. That night was also illuminated by the moon (the moonlight reflection can be seen on the dome itself) which makes things worse for Milky way to become more prominent in the photos.

Below are examples of how higher f-stop/f-ratio allows less light through, thus increasing your exposure time, which introduces noise and other issues such as shaking, star trails, etc.

Niklas Henricson

Moon and Venus in conjunction

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Tonight Venus and the Moon were in conjunction. A beautiful show that was clearly visible in the Sacramento, CA area despite clouds in the horizon

Camera: Canon EOS 50D – with tripod and remote control
ISO: 500
Exposure: 2 secs
Focal Ratio: f/4.5
Focal Length: 96 mm
Original Dimensions: 4752 x 3168 px
Time: 4/17/2018, 7:37 PDT
Location: Sacramento CA, US
Post Processing: Adobe Photoshop CS6

This slideshow requires JavaScript.

Niklas Henricson
Sacramento, CA

Great American Eclipse – More photos

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Three days after this magnificent eclipse I managed to process through some more photos out of my camera’s memory card. Unfortunately, I didn’t get to capture the diamond ring before the totality, just the one the came afterwards. Regardless, I am happy the sun got sunspots 2671 and 2672 clearly visible. It made the job a whole lot easier.

All images were photographed with a Canon EOS 50D, DSLR camera on prime focus method on a William Optics 110mm FLT APO f/7.0 telescope. While the live video on Youtube at the day of the eclipse was a Samsung Galaxy S7 phone with afocal method on a 32 mm ocular attached on a William Optics Megrez 72mm FD f/6.0.

The camera settings were, ISO-500, shutter speed at 1/3200 sec., 6000 K and the wheel setting was on M (manual mode).

Below is a composite image of all the solar eclipse phases that are displayed individually on the slideshow above. Click on the image below to expand it to its full size.

Mosaik-Entire-Eclipse
Solar Eclipse – Composite image

Niklas Henricson

Supermoon 2016

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So it was time to head out of the apartment and head for my spot to take a nice shot of the supermoon. I sneaked out as quietly as I could and try to avoid waking up my wife and our baby sleeping still heavily. I left around 4:30 AM and started driving towards the TRACON area (TRACON is responsible for air traffic control for the whole West of US). Once I arrived I turned in their parking lot, but a security guard approached me letting me know I wasn’t allowed to park there but they were kind enough to advice me to park across the street. I thanked them and also asked them if they knew about the supermoon showing up this morning and their response was “Yeah! We’ve been watching it all night”. I left shortly after our short conversation looking at the security guards gazing high up in the night sky all in awe about the brightens of this beautiful full moon.

I couldn’t center the statue I had in mind (a statue of army pilots pointing towards the sky. I thought it would have been awesome to put the moon at their finger tips but that plan and angle didn’t work all too well because of the tree line in the way) and so I changed quickly plans and had the Californian state flag and US flag poles centered in the middle. Fortunately from that angle the trees weren’t in my way.

And here we go, supermoon in all its glory

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For you who have missed this event, there’s one more chance the 13th of December. I’ll be back about it and might make a new try again for my perfect shot.

14th of November – Super Moon

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The 14th of November this year the moon’s perigee position and phase (full moon) will offer all the observers a spectacular show. It will appear the biggest in 70 years. So to all my California friends, go up this early morning around 5 AM and take photos. I will try and see if I can find a nice recognizable monument in Sacramento (maybe the tower bridge).
The moon will be already descending towards the West and its declination or angle close to the horizon will cause the moon to appear larger than its actual size. It is actually worthy witnessing this beautiful event, as it will not happen again for another 70 years. There is however one more chance during next full moon in December (12/13/2016) if you happen to miss it. In December you’ll have to look out even for the Geminids Meteor showers, however do not make many hopes as the full moon brightness will make it harder discovering them.

In order to take a nice photo of this event you’ll need to stand far away from an object/monument or building of your choice and use a telescope or a telephoto lens that will magnify enough the size of the moon while keeping your object in focus.

While moving away from that object will reduce its size due to the distance from it, use your telephoto lens to magnify it. That is how you accomplish these images like in the example below (a large moon and a recognizable building/object next or right in front of it).

Unfortunately cell phone cameras will not be able to take any good images as these get worse by using zooming/image enlargement and also over exposed (bright sphere with unrecognizable features). Unless of course you are able to control shutter speeds and ISO values (such as in some Microsoft/Windows phones). For this image you’ll need a tripod and a DSRL/SRL camera with telescope lens to accommodate your needs properly.

Links:

Click on the mosaic below for larger images:

moon
Moon’s position in Sacramento, CA area the early morning of 11/14/2016

IMG_4538
Standing too close to the building will allow you large objects on the ground and the moon to appear tiny

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Image from National Geographic used as an example. By positioning yourself far away with a telescope or telephoto lens it’ll make objects and the moon larger put together side by side

 

Moon in conjunction with Jupiter

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So I’m soon done with the visa process while enjoying a wonderful summer in Sacramento, CA with Melissa, little Vanita and waiting soon for our daughter to be born. Right now life is good. We’re starting anew, with exciting opportunities in all areas of life.

While Melissa was enjoying a movie at the theater with her friends, I managed to assemble together my camera and lenses to go out and shoot a few pictures on the moon. I really love the crescent moon as the shadows illuminate the crates in higher contrast then a full moon does.

Here are the results

Niklas Henricson

Mercury’s Greatest Transit

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Mercury-Transit

I’m soon about to move in with Melissa and start our lives together in Sacramento, CA. On my last visit to the states, I left all of my DSLR cameras at her place. I realized since I don’t have any cameras left in Sweden, I had to use my Celestron NexImage webcamera, but of course it’s not compatible with Windows 10! After spending almost an entire morning trying to install Windows XP Home edition through Hyper V Manager and also trying to install all the old Windows XP drivers from the Celestron’s CD I finally succeeded to get the webcamera functioning.

Mercury-Transit2

My idea was to broadcast live stream and share that with others, but I found myself abandoning that idea quite soon due to connectivity issues and also due to the camera not being setup properly.

Selfie

To my disappointment, I was running out of time and had to cancel my effort in trying to bring the webcam alive. The event would start at 1:15 PM local hour so instead I captured the event through the afocal-projection method by pointing my Windows cell phone (a Nokia Lumia 1020) against the ocular and to my surprise the phone captured a semi-good photo and a video of the event!

The next visible Mercury transit will occur in 2019 but will not be as spectacular as this one (so called a great transit). The next great transit will be again the 9th of Noveber in 2052. By the time I’ll be 73 years old and hopefully will be able to see it again!
(See facts about Mercury’s periodic transits). Some more facts in Swedish here

Another interesting fact about Mercury as a planet is its orbit around our sun. Not before Einstein came around with his general theory of relativity, could we explain the eccentricity of Mercury’s orbit due to the large bending of space-time fabric around the planet. Before that, Newtonian physics could explain halfway all the visible observations, which annoyed the scientists. Once again, Einstein could nail the answers to this odd behavior of the planet.

Here’s a Youtube video of the event as well, expand the video to full screen in order to see the round dot on the right side of the solar disc. Mercury is a tiny planet and covers a mere 1/158 of the sun’s diameter. Enjoy watching!