Andromeda Galaxy

A 46 minute exposure of the Andromeda galaxy, M31 – my first serious attempt to image this wonderful neighbour of ours. I’ve captured it before with a camera on tripod and made some half-hearted attempts to shoot it with my telescope in suburbia.

This object will clearly benefit from much longer exposure times, as the outer fringes of the galaxy are not visible.

M31 is only visible here at latitude 34° S. for short periods. It is technically above the horizon daily for about seven hours and is only seen in October and November. It crosses the meridian at an elevation of 14.75° and is only visible through the metropolitan glare of Sydney. So it is a challenging object, even without considering its tenuous outer spiral arms.

Image captured during a field night with Macarthur Astronomical Society.

Speaking of metropolitan light glare, the local council replaced the street light in my street last week with a powerful LED array. The new pole is 1-2 metres higher and the luminaire is unshrouded.  I’m trying hard not to exaggerate but the result is a blinding view of the actual light source itself as I walk out the front door at night and catastrophic glare and extensive light intrusion onto residential properties, including mine.

One thing that authorities need to learn is that street lights should be designed to illuminate the street .  ⛔

If it is their desire, residents should illuminate their own properties.

I’m now scrambling for methods of protecting my optical telescope from unwanted glare. It’s already got a dew shroud and will now need a light shroud extension on it to keep the unwanted glare out.

Not happy!    😠

Object Details:

Designation: Messier 31, M31, NGC 224.
Constellation: Andromeda.
Visual magnitude:   +3.3.
Apparent size:  178′ x 70′
Diameter:   220,000 light years.
Distance:    2,500,000,000 light years.
Altitude during exposure:   12.5° rising to 14.25° above N. horizon.
Also in image: galaxies M110 (NGC 205), M32 (NGC 221) and NGC 286.
Astrometry overlay image:

Blog ends here. All the technical stuff follows:


Exposure:  27 x 103 sec  =  46.3 min.
Gain: 0
Date:  2019-10-19.
Location:  semi-dark rural.
Moon: no.
Conditions:  clear.
Sky:  1.19  e/pixel/s (poor).


Image acquisition:  SharpCap.
Method: Live stacked.
Darks:  6x.
Image post-processing:  GIMP.
Cropping: no.


Telescope: SkyWatcher Esprit  Type: 120ED triplet refractor
Focal: 840 mm F/7 Mount: SkyWatcher EQ6-R Pro
Camera: ZWO ASI 071 MC Pro
Type: CMOS 28.4mm 16 Mpx
Optical aids: Flattener + LP filter Guiding: Yes
Polar aligning: QHYCCD PoleMaster Polar Error: 56”

Geek Log:

[ZWO ASI071MC Pro]
Debayer Preview=On
Output Format=FITS files (*.fits)
Capture Area=4944×3284
Colour Space=RAW16
Hardware Binning=Off
Turbo USB=40
Frame Rate Limit=8 fps
Timestamp Frames=Off
White Bal (B)=50
White Bal (R)=53
Cooler Power=34
Target Temperature=-5
Auto Exp Max Gain=300
Auto Exp Max Exp M S=30000

Auto Exp Target Brightness=100
Mono Bin=Off
Anti Dew Heater=On
Banding Threshold=35
Banding Suppression=0
Apply Flat=None
Subtract Dark=C:\Users\Roger\Desktop\SharpCap Captures\darks\ZWO ASI071MC Pro\RAW16@4944×3284\103.1s\gain_0\dark_6_frames_-5.3C_2019-10-19T10_37_10.fits
#Black Point
Display Black Point=0
#MidTone Point
Display MidTone Point=0.638095238095238
#White Point
Display White Point=1

Image © Roger Powell


  1. Boy, I agree with you about the LED street light. The same occurred on my street here in a tiny village in Eastern Ontario Canada (near Ottawa). Do you think they were on sale somewhere?

    Liked by 1 person

    1. Thanks, Fran. I think LEDs consume a lot less energy than HID lights, so designers take the opportunity to boost the light output. I remember when residential street lights had 60 watt incandescent globes which gave out very little light. We managed somehow!


  2. That a really nice capture considering the tight angle you’ve been working with, by contrast, this time of the year for me Andromeda will cross the meridian and I’m ashamed to say that I’ve never really given this a serious attempt to shoot except long exposures with a DSLR. On the bucket list for sure.

    Liked by 1 person

    1. I don’t like making excuses but low northerly objects like M31 are tough here because they are viewed through the metropolitan sky glow. That said, I’m going to try M33 tonight. It’s a few degrees higher.
      Thanks for commenting!


  3. That is a beautiful image. As to light pollution, I hear you. There is a street light pole at the end of my driveway. I want to cut it off. But the utility company would notice. It isn’t LED yet. The newer ones I’ve seen are reasonably well directed down to the streets.

    I read a study saying that the decreased cost of LED fixtures and operation has actually increased the amount of light pollution. Cities figure they can add more and brighter lights because they cost less in the long run.

    Liked by 1 person

    1. You are spot on. They put in LEDs which reduce the power consumption but choose a fixture which emits more light, still wasting energy by sending it where it shouldn’t go.
      Combine that with the fact that light pollution filters will be of no use to filter out LEDs and it will be a disaster for astronomers.


    1. Yes, large observatories have the clout to get government and council regulations in place on light pollution. I know Australia’s largest optical observatory at Siding Spring, here in NSW, has done just that, with a primary local zone and a secondary 200km zone. Not much chance of my local council doing that!

      I’ve read about the differences of opinion about the TMT proceeding on Hawaii. My sympathies are with both sides. I love the idea of such a huge telescope and the amazing science it can do – but I don’t like seeing the rights of indiginous folks being ignored. I hope it gets resolved amicably.


    2. Yeah . . . take that with a grain of salt. It’s my impression (and I admit I could be mistaken) that’s a) a relatively recent thing, and b) a small vocal minority.

      There’s also the perception that “indigenous people” are united in this fight against forces that want to encroach in their culture. Nothing like that. Based on three years living there, I feel comfortable in saying there are plenty of natives who would welcome the economic boom the construction project would bring. I would say it’s a majority. The reason everyone tiptoes is because of the “religious” thing.

      The interesting thing (and mostly ignored) is the association of the protesters with people who want to reclaim sovereignty of the islands. It should be (again) noted that those groups are a minority.

      My impression (from speaking with working natives) is that those groups are basically lazy and unwilling to work and that they blame “the man” for oppressing them (their words, not mine).

      As usual, it’s difficult to discern what’s what. I know that developers are wary of doing project there because of the likelihood of hitting some “cultural” landmark or other and having their permits put on hold.

      There were settlements all over the island for hundreds of years so hitting ruins isn’t all that difficult . . . and they are never the remainder of a cesspool or storage for dead fish. Nope!

      Amazingly, every ruin found is a holy and most sacred place that until focused on because money and notoriety is involved, no one cared about. To my skeptical eyes, every instance I saw of cultural preservation benefitted the few organizations and offered no benefit to the population at large. In fact, I’m comfortable that every instance I saw and read about when I was there was to the net detriment of the place and its population.

      But, I’m not indigenous to the place . . . and that’s one reason I left (among others).

      Liked by 1 person

      1. Thanks for the inside information.

        I can’t comment much more about an issue I know little about. I think, in general, indiginous people need to be listened to but as you say, sometimes the loudest don’t always speak for them all.

        I do tend towards cynicism when I learn a place is described as “sacred” or “spiritual” – adjectives which have no meaning whatsoever to me – probably designed to project an unwarranted aura of importance!


  4. Nice image especially considering the low angle. I was not aware NGC 205 had been designated M 110, perhaps a testament to the last time I had viewed it.
    And, it is sad that so often municipalities ignore the value of reasonable lighting policy, especially in suburban areas. M 😦

    Liked by 1 person

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