Gippsland Star Party 2024

Aside from my first trip to the ASV’s Dark Sky site when there was a large number of astro enthusiasts present; I’ve never attended a real ‘Star Party’ where people get together under the night skies and spent a night (or more) imaging and observing.

So I had expectations for a good turn-out to the inaugural ‘Gippsland Star Party’ held over the weekend of March 15th to 17th. The location (Stockman’s Camp, Buchan South) promised very dark skies, far away from the light-dome of the city.

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I never counted how many people attended the event but I heard one of the organisers say that they had 50 people registered. I could count the number of people in the group photo, I suppose… Looking up and down ‘Telescope Alley’ there were (at most) two dozen scopes setup; ranging from small refractors to 12" or 14" Dobsonian monsters. Of particular note was the 16" Dob - that was a monster of a device, being well over 2 metres long. Parked next to it was a very diminutive ZWO ‘SeeStar’.

The light pollution from the nearest towns (Orbost, an hour’s drive to the South-East) and (Bairnsdale, an hour’s drive to the South-West) made no impact to the night skies. One of the attendees measured an SQM of 21.7 - fractionally off the much-desired Bortle 1.

Interestingly, there was enough sky-glow at the horizon that you could see the difference between the surrounding hills and the night sky. Overhead was the silvery-white trail of the Milky Way, bright enough to walk around by.

The only down-side was the insane amount of dew. Once the sun went down all the moisture in the air condensed onto any available surface - the grass, cars, tents, tables, telescopes… If you didn’t have a dew heater on your telescope / camera lens then you were in for a very bad night. It was so bad that I ended up with pools of water on my equipment cases, and resorted to putting my laptop inside a plastic shopping bag to keep it dry. I had my DSLR setup there as well, planning on taking some wide-angle nightscape images. Sadly the dew was so bad that I had to give up on that idea and stick to imaging with the telescope.

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I had two targets that I wanted to image - a 2x2 panel mosaic of the Eta Carina Nebula (NGC 3372) and another attempt at The Tarantula Nebula (NGC 2070). Yes, I’ve imaged these before, but never under such dark skies in excellent conditions.

This was also my first real attempt at working with KStar’s Sequence generator. I had created the setup files before I left home and I have to say that the Mosaic Planner makes things very easy once you have read the manual a couple of times and carefully made your way around the interface.

Once the skies were dark enough, I polar aligned the mount - being in a new location I had no reference points to work with. I had tried to get a rough alignment during Friday afternoon except that the compass on my phone was totally useless, being about 45 degrees out. One other attendee had a GPS unit and helped me immensely by locking my position in the unit, then walking around until he was exactly south of me. Once I had a reference point to point the mount at I was able to get the system properly aligned through the Ekos Polar Alignment routine and then fine-tuned with the PoleMaster once the skies were dark.

I neglected to check how many hours of darkness I was going to have, so opted to take 45 minutes of data for each panel of the mosaic. 6 hours in total should be enough, right?

Everything ran smoothly - the alignment, auto-focus and guiding all worked exactly as they were supposed to. Once the rig was imaging correctly, I tried to get the DSLR running but ran into the dew problem I mentioned before. So I wandered around seeing what the other attendees were doing.

At around 1am the rig was due to do it’s Meridian Flip (where the entire telescope slews from one side of the mount to the other, with a 180 degree rotation) to avoid running into the tripod leg. There are various short videos on YouTube if you want to see a flip in action.

Frustratingly, it failed to re-align with Eta Carina. I could see Ekos capturing the alignment image and doing it’s plate-solving but the mount never responded to the movement commands. I tried a few things and opted for the Microsoft solution - a complete reboot of the mount and the laptop to obtain a clean start-up. This worked, and once the sequence was running again I retired to bed for some well deserved sleep.

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Saturday was spent relaxing before having lunch at the Buchan Pub and a drive up into the surrounding hills / mountains.

I really do enjoy getting out of the city and into the bush. The smell of the gum trees, the various bird songs, and the peaceful serenity are very soothing.

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When I inspected my images from Friday night, I was disappointed to see that a light fog or high-level cloud had rolled in after I’d retired to bed and the final two mosaic panels were pale and washed out. I took the decision to reduce the amount of time I’d spend on NGC270 and re-do the two mosaic panels.

My next planned imaging set was a repeat of the Eta Carina mosaic, but using the UV-IR cut filter to capture short exposures (30 frames of 30 seconds for each panel) to get the proper star colours. My plan being to use the narrowband filter data for the nebulosity and then overlay the true-colour / broadband image of the stars.

Once the UV-IR data had been captured, I re-did the narrowband mosaic panels. I could have probably gotten away without doing this, but why risk a dud image if you have the opportunity to save it?

Once these had completed I was able to kick off the sequence to capture NGC2070 and wait for the Meridian Flip. This time, it worked perfectly - no faults at all. So again, I retired to get some sleep.

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Sunday was spent packing up the camping gear once it had all dried out enough, loading the car and then driving back home. We stopped at Lakes Entrance to walk on the beach and get our feet wet in the waters of Bass Strait.

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The processing of the Eta Carina data is a bit of an epic. To shorten a long tale, I stacked all four groups of narrowband with Sirilic’s multi-session settings to give me 4 images, then did the same with the broadband data. These were calibrated in Siril to properly align them, colour calibrate and then stretch into linear data before being exported in a format I could feed into my mosaic software. (If this sounds tedious and repetitious, it was!)

Several of the stacked images had to be rotated and flipped so they had the correct orientation. It’s a bit hard to make a mosaic if half the panels are the wrong-way around!

Oddly, AutoPanoGiga failed to stitch the frames together into a usable image and I had to resort to Affinity Photos’ Panorama Tool. Which worked perfectly.

I then fed these two mosaics back into Siril to process them with starnet++ and tweak the colours / contrast and brightness via the Generalised Hyperbolic Stretch (GHS) functionality.

I had hoped to combine both sets of nebulosity data to get a more “true colour” picture of Eta Carina but there was some sort of rotational distortion in the broadband image and I was forced to discard the entire data set.

From here, it was a simple matter of recombining the narrowband nebulosity image and the narrowband stars back into one image before processing it with Affinity photo.

The Affinity Photo image was about 3.5 gigabytes in size by the time I’d finished processing and had it ready for exporting.

Image data:

• Gain: 100
• Offset: 10
• Temperature: 0 degrees C
• Exposure: 120 seconds
• Frames: 45 Lights per panel, 50 Darks, 50 each of Flats and DarkFlats (6 hours integration in total)
• Filter: L-Enhance

Discarded Image data:

• Gain: 100
• Offset: 10
• Temperature: 0 degrees C
• Exposure: 30 seconds
• Frames: 30 Lights per panel, 50 Darks, 50 each of Flats and DarkFlats (40 minutes integration in total)
• Filter: UV-IR Cut

Processed with Sirilic and/or SiriL (stacking, pre-processing, starnet++, basic stretching) before tweaking in Affinity Photo v2

Equipment: SW72ED@420mm / HEQ5-Pro / ASI183MC-Pro / SV165+SV305 / Kstars/Ekos

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In contrast, the processing of NGC 2070 was a simple and straight forward process. The hardest part was making the tiny, incremental steps with the GHS to best bring out the details in the nebulosity without saturating the core. Looking at the final image, I think it came out quite well.

The only downside is that I didn’t have enough darkness and the Ekos sequence module terminated everything at the end of true night and the start of astronomical dawn. Otherwise I would have had 4 hours of data to work with.

Image data:

• Gain: 100
• Offset: 10
• Temperature: 0 degrees C
• Exposure: 120 seconds
• Frames: 102 Lights per panel, 50 Darks, 50 each of Flats and DarkFlats (just over 3 hours integration in total)
• Filter: L-Enhance

Processed with SiriL (stacking, pre-processing, starnet++, basic stretching) before tweaking in Affinity Photo v2

Equipment: SW72ED@420mm / HEQ5-Pro / ASI183MC-Pro / SV165+SV305 / Kstars/Ekos

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For both of the images below, I strongly suggest right-clicking on them and selecting the ‘Open image in new tab’ option to see them at a larger size. These thumbnail images don’t let you see the full detail hiding in the gas / dust clouds.

Those labelled “2k” are 2048 pixels on the longest side, whilst those labelled “4k” are 4096 pixels on the longest side.

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Huge thanks to the organisers of the event, and our hosts at Stockman’s Camp. I’m already looking forward to the next Gippsland Star Party in late March 2025.

• Astro