Astrophotography from Sydney

Article originally written for the AAO’s Newsletter published on 29th June 2021.

During the last year I’ve been setting up my telescope in the backyard to do astrophotography as an amateur astronomer. This has been possible thanks to getting a good mount (Skywatcher AZ-EQ6-Pro) that allows me to do auto-guiding, and using a little but very clever device (it’s a modified Raspberri Pi manufactured by ZWO called “ASIAir”) that allows me to connect mount and cameras (the main camera for astrophotography and the auxiliary camera for auto-guiding) together, being everything controlled using my son’s iPad (who, with only 8 years, has been also helping me with all of this). In the last months I’ve been able to get a process so smooth that I only need 10 minutes for setup (checking polar alignment, guiding, focus) and then the telescope is observing all the night (it will automatically move to a parked position at the end of the run).

My amateur telescope equipment in April 2021
My amateur telescope equipment in the backyard (15 km from Sydney’s centre) ready for astrophotography in April 2021. The telescope is my Skywatcher Black Diamond 80, f=600mm (f/7.5) that I bought for the Transit of Venus 2012. The x0.8 Orion focal reducer is included here. I use the ZWO ASIAir to control the main camera, the mount (Skywatcher AZ-EQ6 Pro) and the guiding system (ASI120MM + Orion 50mm finderscope). The ZWO Filter Wheel has 7 positions with 2” filters (ZWO LBGR filters, Baader 3.5nn H-alpha, Antlia 3nm [O III], and a hand-made dark filter). The main camera is a ZWO 1600MM-Pro, usually set at -20C.

I must confess this has been a lot of fun for me, also for keeping extra busy and awake during the many meetings / workshops in the middle of the night we all are having lately. I’m getting some nice photos, particularly of nebulae, as I’m using some ultra-narrow (3.5nm thickness) H-alpha and [O III] filters. One of my favourite images is the Cat’s Paw nebula, who would have told me just some few years ago I will be able to get such an image with all these details using a 80mm refractor telescope in Sydney!

Fire in the Cat's Paw Nebula
Deep H-alpha image of the Cat’s Paw Nebula (NGC 6334) in Scorpius obtained from my backyard, 15 km from Sydney’s city centre. All the information in my Flickr. Credit: Ángel R. López-Sánchez (AAO-MQ).

Hence, when last May, I was starting to use TAIPAN and observing with this new instrument, I couldn’t help myself…

While Tayyaba and Anthony helped me to get trained for TAIPAN observing, I decided to check if the instrument could be used for observing HII regions in the outskirts of the nearby spiral galaxy M 83, as well as observing the dwarf galaxies in the neighbourhood. Unfortunately this has been hard for the 1.2m UKST because of the faintness of the targets, but at least I got some test data from the central parts of M83 and some dwarf galaxies, including beautiful starburst NGC 5253. 

However, I was thrilled to be using TAIPAN to observe M83 while, at the same time, in my backyard, my small telescope was also observing M 83 to get a new color-image of this galaxy. It was quite exciting and rewarding!

Colour image of M83  and surroundings combining data in B, G, R and Luminosity filters (8 hours in total combining 2 minute exposures). Data taken on 16 and 17 May 2021 while observing with TAIPAN remotely from my home office. This is still work in progress. Credit: Ángel R. López-Sánchez (AAO-MQ).

This image is still work in process, because we need to take usually hundreds of frames in each filter to get a good astronomical image to mitigate the light pollution plus reducing the background noise as much as we can. And, of course, dealing later with the processing of the data (it’s not that hard as it sounds, there is actually some software already available for amateur astronomers that does this very quickly in a very efficient way, even considering darks, flats, offsets and median stacking with different options). Also, I still need to add the H-alpha data in this image to emphasise the star-forming regions in the spiral disk of M 83. Unfortunately, the weather over Sydney during the last weeks has not being very good for astrophotography, but I hope to get the rest of the data soon.

Additionally, on Wednesday 26th May we enjoyed a total lunar eclipse. I took almost 2000 images of the event while I was participating in an online live event with many schools in Spain (8000+ views during the day). The telescope setup in this case was different, as I used my CANON 5D Mark III DSLR as main camera attached to my telescope. But, even though the totality of this lunar eclipse was short (only around 15 minutes), I got a very nice image of the eclipsed moon. For this image I combined the same data independently for getting the stars and the moon, and merged them together later.

Total Lunar Eclipse - 26 May 2021
Total Lunar Eclipse on 26th May 2021. This image combines 50 x 1″ exposures, ISO 800, obtained with my CANON 5D Mark III attached at primary focus of my Skywatcher Black Diamond 80mm f600mm (F/7.5) during the Total Lunar Eclipse on Wednesday 26 May 2021, between 9:00pm and 9:04pm, Sydney local time. Full description and high resolution image here. Credit: Ángel R. López-Sánchez (AAO-MQ).

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