Astrophotography in pure darkness

In Michigan, I could only see one nebula – “Michigan Nebula”. Nah, that’s just a joke in the amateur astronomy society here to complain about the frequency of cloudy nights in the state. For me, the complaint is real. I do not have an observatory for regular imaging. Packing such a heavy weight EQ mount and going to some dark rural site only to find cloud building up is almost frustrating and unacceptable. Now it seems a road trip every half year could offer me better opportunity with the best dark sites in the States.

So here are some examples. During the Christmas of 2013, I went to the Big Bend National Park in Texas. There’s absolutely no light pollution from almost any direction except some desert town outside the park. Terrain should perfectly shade these local glares.

At the dusk we entered the park, but from where we were staying took about 1 hour drive. The surrounding lost its colorful appearance when the last patch of sky became completely black. The headlight of our vehicle and the passing by prevent us from dark adaptation. But when we step out of the car, the brilliant zodiac light immediately catches my attention. It was so bright, even under the streetlight in a parking lot, I could see it reaching 30 degrees high in the sky. The clouds kept me blinded for 1 day and half. It was until the third night that I could view it in its full majesty. Until midnight that day, the zodiac light was still bright on the horizon.

Zodiac Light

Zodiac Light

This time, all the clouds move away to the west and it offered a clear night for astrophotography. I picked a spot near the park entrance to setup my tracking rig, and another camera for time lapse. The Orion’s belt was my imaging priority. In a 2 hour and 40 minutes total exposure, I was able to reveal all the dark nebula and dust bands adjacent to the bright M42 and horsehead.

Orion

Meanwhile, the sunset at Rio Grande Village was considered by us to be the most scenic combination after 3 days of lonely drive in desert.

Rio_grande

360 panorama – Sunset of Rio Grande

Now 6 months have passed, another opportunity took me to the Mojave Desert in California. This time, I’ve substitute the glass inside the optical glass inside with one having antireflection coating. Thus all the glare surrounding bright stars and nebula center are gone. About 10 minutes’ drive away from the small desert town Baker, I set up my AstroTrac on the sandy road of Mojave National Preserve. It was dry hot at such a low altitude. Besides the intermittent wind blowing against you, is the occasional sound from some unknown animal sheltering in the wasteland. The glare from Baker and head light of passing cars on I-15 are on my north, the Rho Ophiuchi Nebula is a perfect target. Yet under this dry heat, it was exhaustive trying to sleep inside a car. I manage to get 100 minutes of exposure in total.

Rho Oph

The Rho Ophiuchi Cloud Complex

This time I’m using the hacked firmware preserving the raw output from the sensor. Now with custom made calibration pipeline developed, I could achieve perfect preprocessing before the actual alignment and stacking.

Meteor and Milky Way

An occasional meteor captured during the time lapse at the same night. The Rho Ophiuchi gradually sets into light dome from southern California as my TT-320X tracking it. The background light would still impact the SNR in the dark nebula.

Some 360 panoramas along the way, click to pan and zoom.

image

Devil's Postpile

image

At monolake, I took a panorama of the sky. But it seems more challenging to process. The sky was divided into 7 areas each 4 subframes. Airglow greatly increases the sky background near horizon that night.

Monolake

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5 Responses to Astrophotography in pure darkness

  1. Tony says:

    I would love it if you could give a tutorial on your preprocessing of astro images as referred to in this comment “Now with custom made calibration pipeline developed, I could achieve perfect preprocessing before the actual alignment and stacking”

    Thanks in advance if that is possible

    • jackshencn says:

      Hi, I calibrated the images using R codes. It’s still in test phase. The highlight is to normalized the individual frame before creating the master frame. This is very important in master flat/dark as the mechanical shutter is less accurate and the CMOS in DSLR is not temperature regulated.

  2. Tony says:

    Thanks for the reply, but I’m fairly new to astroprocessing, I’m familiar with dss and photoshop, but I don’t know what calibrating with R codes means.

    Any further explanation would be appreciated.

    Thanks

  3. Tony says:

    Ok thanks Jack, love your work, maybe someday I’ll figure this stuff out

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