Moon

Two Days Before Full Moon

Apparent size:32.5 arc-min.
Diameter:3475 km.
Distance:367,514 km.
Date:2020-07-03.
Exposure:0.124641sec – best 125 frames stacked from 500 frame video.

One of the ‘problems’ of astro-imaging is that a telescope with a camera, is not zoomable. Visual observers can swap eyepieces in a few seconds to narrow the field of view and magnify the target but it’s not that simple with astro-photography.

So, having just added a new accessory which can double the focal length from a native f/7 to an effective f/14 and reduce the field of view, I was anxious to try it out.

The Televue 2X Powermate installed between the camera on the right and the telescope on the left.
The Televue 2X Powermate (chrome and black) installed between the camera on the right and the telescope on the left.

Full Moon is not a favoured time for most astronomers, the glare is too strong for serious astronomy. However, I was desperate to test my new Televue Powermate so I decided that the Moon was my friend.

This image of the Moon, taken by stacking video frames, is evidence that the Powermate is going to be a useful addition to the astro-toolbox and I’m hopeful it will prove useful when imaging smaller objects.


Telescope Details
SkyWatcher Esprit 120 mm apochromatic 3-element refractor.
840 mm focal length @ f/7 with field flattener and 2x Televue Powermate.
Baader L-Booster UHC-S light pollution filter 2458276.
SkyWatcher EQ6-R Pro mount.
Camera: ZWO ASI 071 MC Pro (CMOS 28.4mm 16 Mpx)

15 Comments

    1. Thanks. I took some test images of Jupiter and Saturn during this session which hopefully will be an indicator of how useful the Powermate will be when I try it on small deep sky objects.

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      1. Last night we walked a few blocks to watch fireworks. The Moon was up big and bright. On the way home we spotted Jupiter and Saturn just risen. The 3 will be closer in a grouping the next 2 nights.

        Liked by 1 person

    1. I think this is very good reasoning and explains why more amateur astronomers are doing it.

      It hadn’t really occurred to me because I’ve followed a different path – but of course if you have developed a good technique to hold the phone steady, in the sweet spot, a change of eyepiece is so simple!

      Liked by 1 person

      1. It is a real trick to get the camera, mount, and eyepiece lined up exactly. It’s frustrating at times. Even if it is a little off, you end up with an image clearly taken at an angle, aggravated by a bright Moon reflecting off the eyepiece. And vignetting allows for no tolerance either, if everything is not lined up 99.9% properly. I can see the impacts of vignetting on some of my telescope Moon pictures.

        Liked by 1 person

    1. Thank you. When imaging the Moon itself, its glare can be compensated with exposure adjustments.

      The big problem with amateur astronomy is when taking images of other sky objects like galaxies. Bright moonlight is scattered in the atmosphere, making the sky background lighter. So contrast is lost and objects seem less bright.

      Generally most amateurs take a break for a a week or ten days when the Moon is near full.

      By the way, I appreciate your Sunshine Blogger Award nomination (and your regular comments and questions here). I’ve thought about it and I don’t think I will participate. 😷

      Liked by 1 person

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