The Andromeda Galaxy

Overview

A neighbouring galaxy to our own Milky Way, the Andromeda Galaxy is 2.5 million light-years from Earth and contains in the region of one trillion stars.

Background

I wanted a broadband target to test my new Askar 130PHQ (review here), and the Andromeda Galaxy was well-placed in the sky so won the contest. Shooting at 1000mm means that the field of view is narrower than I’m used to, but I quite like the unusual framing. Maybe I’ll make a mosaic in the future to capture the whole target.

The total integration time here is just 10 hours. This is much less than I normally go for, and to be honest I was expecting to need more data, but was curious to see what I could achieve with 10 hours so went ahead with processing. The end result was so good that I decided to declare it finished. (This also frees me up for my next project, which is testing the new Askar OIII+SII filter, review here).

The total integration time here is just 10 hours. This is much less than I normally go for, and to be honest I was expecting to need more data, but was curious to see what I could achieve with 10 hours so went ahead with processing. The end result was so good that I decided to declare it finished. (This also frees me up for my next project, which is testing the new Askar OIII+SII filter, review here).

I binned the data x2 to achieve a good working resolution, which gave a boost to the signal-to-noise ratio. This lowered the image’s overall resolution which, after a slight crop, is 3080×2056 — still plenty for zooming in to see more detail, or making large prints. I’m actually impressed at how fast I can collect data with this set-up, even ignoring the binning aspect. Slide along the image below to compare two raw stacks, both binx1: on the left is 24 hours of data with the Askar FRA400 (F/5.6) and on the right is 10 hours with the Askar 130PHQ (F/7.7).

Despite being under half the integration time, and a slower F/7.7, I think that the Askar 130PHQ has done a fine job.


This image was used in the Winter 2023/24 issue of community magazine Up Our Street.

Science

100 years ago, the biggest and best telescope on Earth was the Hooker 100-inch on Mount Wilson in California. It was a beast!

This giant telescope was used by famous astronomer Edwin Hubble (namesake of the Hubble Space Telescope) to study the Andromeda Galaxy, although at the time people thought it was a nebula within our own Milky Way.

Hubble made history in 1923 when he discovered a Cepheid Variable star in the Andromeda Galaxy. This is the photographic plate image, along with his note VAR!, meaning Variable.

Hubble was so excited by this because Cepheid Variable stars are “standard candles”, with luminosity directly proportional to their distance from Earth. So, we can use them to accurately measure distance. Hubble realised that this particular Cepheid Variable was far beyond our Milky Way Galaxy. He has shown that the Andromeda Galaxy was a star city far beyond our own. People then realised that the Universe was a lot bigger than they’d realised. For this reason, the Cepheid Variable Hubble spotted became known as “the star that changed the Universe”.

Amazingly, it’s actually possible to glimpse this special star in my photo of the Andromeda Galaxy. I find that quite mind-blowing!

Imaging details

DateNovember 2022
LocationBristol, UK (Bortle 8)
TelescopeAskar 130PHQ Flatfield Astrograph
CameraZWO ASI 2600MC-PRO
MountSky-Watcher EQ6-R PRO
GuideWilliam Optics 50mm Guidescope with 1.25″ RotoLockZWO ASI 120MM Mini
ControlASIAIR Plus
SoftwarePixInsight, Lightroom
FiltersNo filter – 300 x 120 seconds
Total exposure time10 hours
Image creditLee Pullen

Source data

Previous version

I first imaged the Andromeda Galaxy back in September 2021, using my wide-field Askar FRA400 telescope. Here’s the processed image, plus a starless version:

* September & October 2021
* Bristol, UK (Bortle 8)
* Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph
* Camera: ZWO ASI 2600MC-PRO (no filter)
* Mount: Orion Sirius EQ-G
* Guide: William Optics 32mm; ZWO ASI 120MM Mini
* Software: PixInsight, Photoshop, Topaz DeNoise AI, Lightroom
* Control: ASIAIR Plus; ZWO EAF
* 720 x 120 seconds

Total integration time: 24 hours

By Lee Pullen

Seestar S50

Here’s an image of the Andromeda Galaxy taken from my city centre location using a ZWO Seestar S50 smart telescope.


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7 thoughts on “The Andromeda Galaxy

  1. Mark Fowler says:

    Nice picture of our nearest galaxy. I’ve got a plus in the way. I currently use Nina with a very similar setup to yours so will be interesting to compare. Just a question on the power cable setup your using. What’s the plastic surround on the jack plug and does this eleaviate the strain on the socket. I ask this because I own the Pegasus power box that has the same setup which failed and consider this to be a weak point. Happy imaging, God give me clear skies.😁

    Reply
      1. Ryan Parle says:

        That plastic surround is a high shrink ratio (3:1 or 4:1) adhesive lined heatshrink that is used to provide better strain relief, it can be added to many types of connector as a modification, you can simply cut a length that covers the connector body and a section of the wire, slide it on and heat with a hot air gun (or carefully with a lighter).

        Reply
  2. Steven holt says:

    Hi you’ve done a great job from Bristol!
    I kinda go for the starless version , I like to see it in its pure state, think I will always do both versions for all my galaxy shots , seeing a grouping of galaxies definitely looks better starless . Enhances the vastness and isolation of galaxies.

    Reply
    1. Lee says:

      There is something special about the starless galaxy shots, I agree. And it does make it easier to see detail in the dust lanes.

      Reply

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