Sun and Moon

[James G]

Following the recent posts by Brian about Astrophotography, I took a little time to try a few captures of the moon and sun.

#1 Moon 5th July 2017 Moon low approx 30 degrees above horizon.


#2 Full Moon 9th July 2017 Moon approx 45 degrees above horizon.


#3 Sun 9th July 2017 (with one of the best sunspot groups this year)



Moon (full) 1/80s F13 ISO 100
Moon (near full) 1/90s F11 ISO 100
Sun 1/100s F16 ISO 100

Canon EOS M5 with Sigma 600mm telephoto + Doubler (1200mm)
Note: Bayer Solar filter used for sun shot.

C&C welcome

[DigitalScape]

Well done, James. Nice details in the moon surface.

[Shadowman]

Nice series.

[Dave A]

Love the moon detail along the edge.

Dave

[dem]

Interesting series. I wonder why the second moon shot is noticeably sharper than the first one. Is the main difference the height above horizon?

[James G]

Thankyou all for your comments.

I wonder why the second moon shot is noticeably sharper than the first one. Is the main difference the height above horizon?

Dem, there are two main reasons I believe: -
1) yes altitude above the horizon definitely... basically lower down there is more atmosphere to see through, and there are consequently more atmospheric distortions. It was a very warm night after a hot day and as result I think that turbulence was much greater. The second, full moon shot was much higher, the day had been much cooler and it was taken a good few hours later.

2) There is also the issue of focusing. Although the Moon is quite large in the viewfinder, it is also very bright and there is considerable glare. I do try to use distinctive craters to get the sharpest focus, but I understand the eye/brain combination can compensate for about 3% blur.

I don't think that the second issue of focus was a major problem this time, although I am getting older but I do use an eyepiece magnifier to try and offset any poor eyesight.

(I also use a Hartmann mask on the lens when setting up the rig which behaves like and old fashioned range finder, where a slot image is generated which comes into alignment as true focus is achieved. Trouble is that the 3% issue can still apply!)

One other factor that can affect the sharpness is vibration due to mirror slap, but in this case I was using a Canon EOS M5 mirrorless camera.

[JBW]

I bow to the master. #2 is a fine shot. Looking forward to seeing some crescent moon shots from you. Question: Are solar flares doable with a DSLR?

[James G]

I bow to the master. #2 is a fine shot. Looking forward to seeing some crescent moon shots from you. Question: Are solar flares doable with a DSLR?

Brian, definitely no master.... but I admit to a little skill

As regards Solar flares no... not possible. Though there is a technique during a total eclipse when it is possible to see and photograph solar flares.
Flares/prominences are a lot less bright than the main disc of the sun, and our atmosphere tends to cause too much diffusion/scatter.

You can get a specialized filter which only passes hydrogen alpha light. These can be used in front of refractors, or you can use a dedicated solar telescope like the Coronado PST (Personal Solar Telescope). Problem is the cost, £1000+ for the PST and I think even the filters for a refractor cost in the hundreds.

I made my own solar filter using Baader Mylar (guaranteed to filter 99.99% of the suns radiation) a couple of years back for about £25 which was the cost of an A4 sheet. It enabled me to get some images of the last transit of Mercury, even though it was a day of intermittent cloud.

I live in hope of a day when I can catch a transition of the ISS across the face of the sun and the bonus will be if there are a number of decent sunspots.

There is also a Calcium K filter which is a blue/UV line. It tends to be used for photography of the surface structures but is not too good for 'visual' observations by people of our age ( who have deteriorating vision)... apparently youngsters fare better with the blue end of the spectrum.

[Wavelength]

Well done images

[dem]

Thank you James for your detailed response. I will be looking for a clear cold night with the Moon high above the horizon next time.

600 mm x 2 x 1.2 = 1920 mm equivalent is very impressive though - the Moon must almost fill the frame. When shooting with a 600 mm equivalent I was surprised how quickly the Moon moves out of the frame. It is not enough to cause motion blur at 1/100 sec but still noticeably fast.

[IzzieK]

Sorry to be late here, James...been busy these last few days in the garden with the temperature rising more than a 100°F. Anyway, the first moon is a little bit elongated and has that purple ridge at the top (chromatic aberration?). #2 is better and the sun spot on the third is really good. Thanks for the detailed response to Dem. I have been looking for an alternative (a sheet) for using on August 21 solar eclipse as it will pass our way here in Missouri. I did not think of looking for astronomy films. Thanks again...

[James G]

Hi Izzie, Duh! you are right there is a little blue there...should have picked it up!

[IzzieK]

Come to think of it, looking at all of them, #2 moon is very sharp and all that, it has a thin layer of blue chromatic aberrations too, the first one has purplish one.

[bnnrcn]

#2 for me too James I too can see the CA which Isabel already mentioned. It is easy to fix it in PP