3 Minute Andromeda Galaxy Comparison

In October, I got this fantastic picture of the Andromeda Galaxy from Dell City, Texas with its Bortle 2 – 3 dark skies.  

Camera geek info:

  • Canon EOS 60D in manual mode, 179 second exposure, ISO 1600, custom white balance 3500K
  • Williams Optics Zenith Star 73 III APO telescope
  • Williams Optics Flat 73A
  • iOptron CEM40
  • Dell City, Texas Bortle 2-3 dark skies

I wanted to see what happened when I used the exact same setup and settings from my driveway in Friendswood, Texas with its Bortle 7 (much much brighter) skies.  My suspicion was that the picture would be all white.  

On my first opportunity to try the experiment, there was also a two days past full Moon in the same section of the sky.  As you can see, I did get an almost all-white picture.

I backed off to ISO100 to avoid overexposing the picture, but then I didn’t get near the detail that I got from the dark skies.

I didn’t know how much the overexposure was due to the near-full Moon and how much was due to light pollution.

Yesterday, I got the chance to try the experiment again with no Moon.  As you can see, at the dark skies setting, I again got an almost all-white picture.

I backed off to ISO100 and ISO400 to avoid overexposing the picture, but again I didn’t get the detail I did under darker skies.

All of the pictures in this blog post are unprocessed, other than being saved to a lower resolution format.  It will be interesting to see what I can get when they are processed.

How dark are your skies?

SiteBortleMoonExposure LengthISOResult
Dell City, Texas2 – 3No Moon3 minutes1600Gorgeous detail in M31, M32 and M101 visible
Friendswood, Texas7Near Full Moon3 minutes1600Almost all white picture
Friendswood, Texas7Near Full Moon3 minutes100M31 as a fuzzball, M32 and M101 not obvious
Friendswood, Texas7No Moon3 minutes1600Almost all white picture
Friendswood, Texas7No Moon3 minutes100M31 as a fuzzball, M32 and M101 not obvious
Friendswood, Texas7No Moon3 minutes400M31 as a larger fuzzball, M32 and M101 barely visible

3 Minute Pictures from Dell City – October 2022

A few weeks ago, we took my telescope and tracking mount on a road trip to our favorite Air B&B in Dell City, Texas.  My telescope and I enjoyed the dark (Bortle 2-3) skies.

Here are some three minute long exposure images I was able to get:

Andromeda Galaxy (M31) plus two satellite galaxies (M32 and M110).  The Andromeda Galaxy is the nearest large galaxy to our own, at 2.5 million light years away.  Its apparent size is 3.167 degrees by 1 degree.  In comparison, the Moon has an apparent size of 0.52 degrees on average.  The Andromeda Galaxy filled the screen on my camera – this image is not cropped at all.  It has an apparent magnitude of 3.44. 

Triangulum Galaxy (M33).  The Triangulum Galaxy is the third largest galaxy in our local group, after the Andromeda Galaxy and the Milky Way.  It’s 2.73 million light years away, and its apparent size is 1.2 degrees by 0.7 degrees.  It has an apparent magnitude of 5.72.  

Crab Nebula (M1) with Mars.  M1 is the remnant of a supernova observed in 1054.  It’s located in the Milky Way, 6500 light years away.  Its apparent size is 7 arcminutes by 6 arcminutes, and it has an apparent magnitude of 8.4.  Mars, of course, is the fourth planet in our own solar system, and the brightest object by far in the image.  

Eye of God (or Helix) Nebula (NGC7293).  The Helix Nebula is planetary nebula – the gases expelled from a star before it becomes a white dwarf, lit up by that star.  It’s located in the Milky Way, approximately 655 light years away.  Its apparent size is 25 arcminutes, and it has an apparent magnitude of 7.6.  

Orion Nebula (M42).  The Orion Nebula is one of my favorite objects in the sky, and one I’ve photographed before.  It’s a diffuse nebula, a cloud of dust and gas that is forming new stars.  It’s located in the Milky Way, about 1344 light years away.  Its apparent size is 65 by 60 arcminutes, and it has an apparent magnitude of 4.

Camera geek info:

  • Canon EOS 60D in manual mode, 179 second exposure, ISO 1600, custom white balance 3500K
  • Williams Optics Zenith Star 73 III APO telescope
  • Williams Optics Flat 73A
  • iOptron CEM40
  • Dell City, Texas Bortle 2-3 dark skies

I’m really looking forward to photographing these from my suburban driveway to see how the images compare.  It will be interesting to see if I get a white screen (pure light pollution) at these settings.  I’ll let you know!

I’m also looking forward to learning how to stack together a sequence of images with PixInsight to see what an hour plus image looks like.  I’ll share that when I figure out how to do it!

October 30, 2022 New(ish) Astrophotography Tools

Camera geek info:

  • Panasonic DMC-GF7 set at f/2.5, 30 second exposure, ISO 800
  • LUMIX G 14/F2.5 II, 14 mm fixed
  • Tripod

Camera geek info:

  • Panasonic DMC-GF7 set at f/2.5, 10 second exposure, ISO 6400
  • LUMIX G 14/F2.5 II, 14 mm fixed
  • Tripod

Since summer 2021, I’ve been acquiring some more advanced astrophotography tools (toys?).  

My first and biggest acquisition was a new tracking mount with GoTo capability, an iOptron CEM40.  This was my first GoTo tracking mount, and it is amazing.  It is so much easier to enter the object to point towards and watch the mount rotate to point the camera there than to iterate on camera images to find the object.  It is also a beautiful mechanical device.  I bought it because of its design and because it is relatively lightweight but could still handle the 8” or 10” telescope I eventually wanted to get.  However, it came with a steep learning curve.   

One thing I learned was that there are two different alignments that need to be done: the polar alignment to physically align the tracking axis with celestial north, and the GoTo alignment.  Just polar aligning is not sufficient.

For polar alignment, the mount comes with a polar alignment camera, but when I got it, the software only ran on a PC, which I did not have (there is a Mac version now, but I have not played with that yet).  So I was using the polar iterate align option with the digital display on my camera, and that was a slow, frustrating, and sometimes unsuccessful process.  

For the GoTo alignment, I use the three star alignment technique.  I read that the mount will try to combine new alignment measurements with the previous ones, so I delete the old alignment data prior to aligning.  I also search for zero position to get the mount set prior to doing any alignment.

My second acquisition was a Celestron StarPointer Pro Finderscope.  It made a huge improvement in my ability to align the tracking mount over using my camera screen to align it.  

My third acquisition was a Williams Optics Zenith Star 73 III APO telescope.  It is a 430 mm focal length, 73 mm diameter two element refractor.  It is a beautiful piece of hardware.  Although it is significantly smaller than what I originally intended to get, I picked it because I wanted to photograph larger objects such as the Andromeda Galaxy and because the larger the telescope gets, the more difficult it is to point.  And since I was still struggling with alignment … 

My fourth acquisition was a very low end PC to interface with the polar alignment camera.  It made a huge improvement in my ability to polar align the tracking mount.  What, even with a finderscope, was a slow and frustrating process, is now a less than 2 minute process, and much more accurate.

With all that, and a lot of trial and error, I am now very pleased with the images that this setup is producing.  As a teaser, here is a picture of the Andromeda Galaxy (M31).  

Camera geek info:

  • Canon EOS 60D in manual mode, 179 second exposure, ISO 1600, custom white balance 3500K
  • Williams Optics Zenith Star 73 III APO telescope
  • Williams Optics Flat 73A
  • iOptron CEM40

Expect to see more in the future!