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iPhone Astrophotography with Explore Scientific UHC Filter

Posted: 25 February 2021

Wednesday afternoon, 24 February 2021, I was at Oracle State Park, our local IDA "International Dark Sky Park". The session at the Park was to do some preparations for a Virtual Star Party to premiere online on 10 April during International Dark Sky Week, 5-12 April 2021.

Open: Wednesday, 24 February 2021, 1812 MST
Temperature: 77°F
Session: 1602
Conditions: Mostly clear, breezy

12" f/8 LX600 w/StarLock
2" 24mm UWA eyepiece
2" 30mm eyepiece
2" UHC filter

iPhone 11 Pro Max

1816 MST: sunset.

1817 MST: LX600 ON, StarLock OFF, High Precision OFF.

Viewed the Moon, 102X and 81X.

Mounted the iPhone 11 Pro Max on the 2" 30mm eyepiece using the Levenhuk adapter.

1827 MST: iPhone afocal 81X photo of the Moon taken with NightCap Camera (ISO 32, 1/420sec, 1X lens).


1843 MST: viewed M42 (Orion Nebula), 81X. Only stars were visible due to bright twilight sky.

1846 MST: dome OFF.

Calm now.

1848 MST: M42, 81X. Some nebulosity now visible near the Trapezium star cluster.

1900 MST: M42, 81X. More nebulosity visible. The sky was still bright from twilight and the gibbous Moon.

1907 MST: handheld iPhone 11 Pro Max photo of Orion and the Meade 12" LX600 telescope taken with the iOS Camera app (Night Mode, 30 seconds, 1X lens).


1912 MST: StarLock ON.

I then did some tests of iPhone astrophotography of the Orion Nebula without and with the Explore Scientific 2" UHC Filter. As I had never tried using the UHC filter for iPhone astrophotography, the Orion Nebula was a good initial target. Here are some of the afocal 81X StarLock autoguided test images.

No filter, NightCap Camera (Long Exposure, Light Boost, ISO 640, 1sec, 1 minute, 1X lens)

No filter, Camera (Night Mode, 30 seconds, 1X lens)

UHC filter, NightCap Camera (Long Exposure, Light Boost, ISO 640, 1sec, 1 minute, 1X lens)

UHC filter, Camera (Night Mode, 30 seconds, 1X lens)

For this bright object in the bright moonlit sky, it was demonstrated that using the UHC filter can yield usable iPhone images in light polluted skies, whether that pollution is the Moon or human caused. I plan to do additional iPhone astrophotography with the Explore Scientific 2" UHC Filter to test it on fainter objects.

1934 MST: StarLock OFF.

1940 MST: LX600 OFF.

1944 MST: dome ON.

Close: Wednesday, 24 February 2021, 1950 MST
Temperature: 58°F
Session Length: 1h 38m
Conditions: Mostly clear

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