July 2022

Starting with a Camera Tracker

by Don Selle

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On occasion, I have talked or traded emails with a new HAS member who was interested in learning astrophotography but was hesitant to get started. The one reason most often given for the hesitation has been that the cost of the equipment is prohibitive. This is followed closely by “if I get into it, I know I will go all-in”.

While I can’t help much with the second reason (after all -- there’s always an upgrade!) there are some ways to get into astrophotography without totally breaking the bank. One of them is to start by using one of the more advanced camera trackers which are currently on the market. 

If you are already into photography, especially landscape and wildlife, adding a camera tracker can open the door to both nightscape and wide field astrophotography. If you already have a camera, sturdy tripod, and a good wide field lens (for nightscapes) and a good telephoto lens (for wide field astrophotography), a camera tracker is the next logical step. You can find used units in the $2-$300 while a new one with most of the bells and whistles will set you back a bit over $500, with a little bit of practice, your results can look really high end. 

Starting with a Camera Tracker

by Don Selle

tracker.jpg

On occasion, I have talked or traded emails with a new HAS member who was interested in learning astrophotography but was hesitant to get started. The one reason most often given for the hesitation has been that the cost of the equipment is prohibitive. This is followed closely by “if I get into it, I know I will go all-in”.

While I can’t help much with the second reason (after all -- there’s always an upgrade!) there are some ways to get into astrophotography without totally breaking the bank. One of them is to start by using one of the more advanced camera trackers which are currently on the market. 

If you are already into photography, especially landscape and wildlife, adding a camera tracker can open the door to both nightscape and wide field astrophotography. If you already have a camera, sturdy tripod, and a good wide field lens (for nightscapes) and a good telephoto lens (for wide field astrophotography), a camera tracker is the next logical step. You can find used units in the $2-$300 while a new one with most of the bells and whistles will set you back a bit over $500, with a little bit of practice, your results can look really high end. 

OSIRIS-REx Has a Blast with Bennu

By Will Sager

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Asteroid 101955 Bennu (NASA photo)

In late 2020, the NASA OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security – Regolith EXplorer) spacecraft tagged asteroid 101955 Bennu hoping to collect a sample to be returned to Earth for study. Scientists hope that these samples, which are thought to be primordial fragments from the early solar system, will provide clues into about planetary formation. Although Bennu threatened to eat the intrepid spacecraft, OSIRIS-REx had a blast. 

 

Asteroid sampling has been attempted twice before by Japan’s JAXA (Japan Aerospace Exploration Agency), in 2005 from asteroid 25143 Itokawa by the Hyabusa 1 spacecraft and in 2019 from asteroid 162173 Ryugu by the Hyabusa 2 spacecraft. The first Hyabusa mission had technical difficulties that resulted in a malfunction of the sampling probe and recovery of < 1 milligram of material. Hybabusa 2 was more successful, but the recovered sample was still quite small at 5.4 grams ( about 0.2 oz). OSIRIS-REx was more ambitious, with a larger sampler called TAGSAM (Touch-and-go Sample Acquisition Mechanism), which was supposed to gather about 60 grams of material from the asteroid surface. To visualize TAGSAM, think of a large, high-tech toilet plunger about 30 cm (11.8 inches) across. The sampler, of course, is made of aluminum (not rubber). It has a ring of jets around the periphery that fire nitrogen gas to stir up small particles and force them into the sample chamber. The TAGSAM is attached to the spacecraft by a thin, articulated arm that allows the sampler to be unfolded and extended about 3.35 meters (11 feet). To collect a sample, the plan was to extend the TAGSAM and move the spacecraft slowly towards the surface of Bennu, make contact, and fire the nitrogen jets to stir up loose debris, which would be trapped inside TAGSAM by a cover flap. 

After launch in September 2016 and a trip by Earth for a gravity boost in 2017, OSIRIS-REx survived another year in transit, arriving at Bennu in December 2018. It spent nearly two years surveying the surface of the little 500 meter diameter asteroid to find a good spot for sampling. Details about the sample site and sampling are contained in an article in the 15 July 2022 issue of the journal, Science (Lauretta et al., 2022). Mission scientists found a small depression, which they named Nightingale, within a small crater named Hokioi, which has a diameter of about 20 meters (66 feet). At the Nightingale site, the surface was easy for the spacecraft to reach and dominated by grains of small size, which are ideal for the TAGSAM. In contrast, much of the rest of the Bennu surface is covered by boulders. Furthermore, photographic and spectral images suggested that the site contained a mixture of lithologies typical of the Bennu surface.

 

 

Artemis 1: A Trip Around the Moon and Back!

by David Prosper

We are returning to the Moon - and beyond! Later this summer, NASA’s Artemis 1 mission will launch the first uncrewed flight test of both the Space Launch System (SLS) and Orion spacecraft on a multi-week mission. Orion will journey thousands of miles beyond the Moon, briefly entering a retrograde lunar orbit before heading back to a splashdown on Earth.

 

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Full Moon over Artemis-1 on July 14, 2022, as the integrated Space Launch System and Orion spacecraft await testing. Photo credit: NASA/Cory Huston Source: https://www.nasa.gov/image-feature/a-full-moon-over-artemis/

The massive rocket will launch from Launch Complex 39B at the Kennedy Space Center in Florida. The location’s technical capabilities, along with its storied history, mark it as a perfect spot to launch our return to the Moon. The complex’s first mission was Apollo 10 in 1968, which appropriately also served as a test for a heavy-lift launch vehicle (the Saturn V rocket) and lunar spacecraft: the Apollo Command and Service Modules joined with the Lunar Module. The Apollo 10 mission profile included testing the Lunar Module while in orbit around the Moon before returning to the Earth. In its “Block-1” configuration, Artemis 1’s SLS rocket will take off with 8.8 million pounds of maximum thrust, even greater than the 7.6 millions pounds of thrust generated by the legendary Saturn V, making it the most powerful rocket in the world!

 

NSNRound150.pngThis article is distributed by NASA’s Night Sky Network (NSN). The NSN program supports astronomy clubs across the USA dedicated to astronomy outreach. Visit nightsky.jpl.nasa.gov to find local clubs, events, and more!

AP Corner: Let’s Get You Calibrated!

by Don Selle

How to Capture and Process Astro-Photography Calibration Frames

Let me start out by being blunt. If you want to improve the results of your astrophotography or your EAA, you must learn how to take and apply calibration frames to every target frame you take before you align and stack them. This is such an important step that experienced imagers refer to calibrating their sub-frames as pre-processing them. In other words, calibrating your sub-frames is so important that it must be done before any image processing is done.

 

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Raw image above – Calibrated image below

Many beginning astro-photographers are either ignorant or ambivalent about taking and applying calibration frames to their hard-won target sub-frames. This is especially true for those of us who set up and take down our imaging rigs (which is most astro-imagers). 

I know this firsthand. Taking and applying darks and bias frames was straightforward for me. I could capture them ahead of time and applying them was easy in any of the astro-image processing apps that I used.

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But flats? That was a different thing all together. It seemed to me that they were difficult to take, adding to my difficulty, I was regularly making changes to my imaging rig, so set up was always a bit of an adventure, 

All Taking flats at evening twilight required being in focus and getting my initial focus required the sky be dark enough that shooting flats was out of the question. 

Dawn flats were also a dodgy option, as I was either taking my rig down and heading back to town before dawn, or (especially in the winter months at the HAS dark site) low clouds or ground fog covered the skies at dawn! 

Fortunately, especially for flats. There are good practices that will help you to efficiently add calibration frames to your imaging workflow and improve your astro-images. But first, a few basics.

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