My astrophotography 2021

CCD vs Film? Lots of time vs no patience? Alright, this is your place to discuss all the astrophotography what's and what's not. You can discuss about techniques, accessories, cameras, whatever....just make sure you also post some nice photos here too!
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hhzhang
Posts: 553
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: My astrophotography 2021

Post by hhzhang »

2021-Oct-16

Tonight it is International Observe the Moon Night!

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hhzhang
Posts: 553
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: My astrophotography 2021

Post by hhzhang »

And here got an image of Venus meets Antares. Also included is an inset of zoomed-in view of Venus -- finally, I have a pic of Venus' phase.

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hhzhang
Posts: 553
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: My astrophotography 2021

Post by hhzhang »

I was testing different FL+F-ration combi on my 150-600 lens. Yesterday I was super disappointed with what turned out from 600mm+F6.3 or even 600+F7.1. So set out to discover what are the working combinations for sharp and round star images? Hmm, the results seem to indicate F6.3 only does well up to ~430mm FL. At 600mm, it has to be F8 to get an acceptable quality for star images.
hhzhang
Posts: 553
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: My astrophotography 2021

Post by hhzhang »

1. What do I do when the night sky is clear? Go out and shoot!
2. What do I do when the night sky is cloudy? Go process the data!
3. What do I do when the night sky is cloudy and the data are all processed? Go re-process the data!

So was this. I reprocessed the Cgynus region data because the original combined image is rather disappointing. After re-processing, the nebulosity seems to stand out better.

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hhzhang
Posts: 553
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: My astrophotography 2021

Post by hhzhang »

2021-Oct-19

Cloudy evening since Oct-17. But the Oct-19 offered a glimpse of Venus through high clouds. That then makes an end note to my attempt to record the transit of Venus through the Antares region.

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hhzhang
Posts: 553
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: My astrophotography 2021

Post by hhzhang »

2021-Oct-21

Caught a glimpse of 67P again, this time using the telephoto zoom lens. The comet is moving towards Episilon Gemini. At mag10.0, it does not show any coma features in the short total exposure under the light pollutions (don't ever forget the full-moon -- hunter's moon). But it appears to be a larger dot than other similarly faint stars.

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hhzhang
Posts: 553
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: My astrophotography 2021

Post by hhzhang »

Before the high clouds rolled in, I used M41 to test the optics of the lens working at 600mmF8 (effective aperture of 75mm).

This is a crop of the image showing the star cluster.

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And this is the mosaic of different regions across the full-frame image, pixel-peeping at 100% zoom.

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Obviously, every star becomes elongated -- thanks to the poor polar alignment. Other than that, the star images are fairly acceptable to my uncritical eyes (because I am a non-astrophotographer, strictly speaking). Kudos to Sigma! However, a few bright stars show unwanted aberrations slightly. My CCD inspector tells me that the sensor is off axis by a little. So definitely some way to improve.
hhzhang
Posts: 553
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: My astrophotography 2021

Post by hhzhang »

A 100% full moon. I have taken many many many full-moon pictures. But perhaps this is the first time it shows 100% illuminated.

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hhzhang
Posts: 553
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: My astrophotography 2021

Post by hhzhang »

2021-Oct-25

The early morning welcomed a lovely clear sky. Went down to shoot comets and Mercury, understanding the gibbous moon was blazing overhead.

67P has passed by Gam Gemini. Despite its close proximity to the moon in the current position, the 135mm-FL image barely shows a little coma feature.

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Yet I went on to shoot 8P in the low sky over the horizon, but it was a little misty, adding to the quickly brightening twilights. And ended up with its 2x60s image being difficult to distinguish.
hhzhang
Posts: 553
Joined: Sun May 10, 2020 4:11 pm
Favourite scope: 115mm APO

Re: My astrophotography 2021

Post by hhzhang »

Anyway, it felt so good to see the Mercury again -- first time after it returned to the morning sky. This reminds me of my observation project back in March when Mercury closely passed by Jupiter and Saturn joined the duo to adorn the morning sky. A lovely bright planet!

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