New Image: Eclipse testing today

[AstroBee]

I didn't feel like dragging out my mount but I wanted to nail down a proper exposure for the partial phases of the eclipse. I'll be shooting with a Canon 5DM2 and a 600mm lens. The 600 is too heavy for me to hand-hold steady so I grabbed the 300mm.
Here's a full frame shot with the 300 and a Thousand Oaks Solar film filter. It turns out, ISO200, f5.6, 1/320 sec was the proper exposure.


The same image, cropped in to approximately simulate the 600mm and AR3590 is very easily visible.

[OzEclipse]

An ND5 (100000x filter) has a nominal exposure of ISO100, 1/500s, f8.

Your exposure ISO200, f5.6, 1/320 sec and you are 9% below middle grey indicates you are closer to ND 5.6 (420000x) darker - that's a good thing!

Joe

[AstroBee]

An ND5 (100000x filter) has a nominal exposure of ISO100, 1/500s, f8.

Your exposure ISO200, f5.6, 1/320 sec and you are 9% below middle grey indicates you are closer to ND 5.6 (420000x) darker - that's a good thing!

Joe

I'll be honest, I'm not a huge fan of this Thousand Oaks filter. Prior to the annular eclipse last October I did back to back testing with it and the Baader ASTF filter and it produced a much sharper image.
I just can't spend money to buy another white-light filter right now and I'm using the only two I have. One Baader ASTF that will be running on my main scope with the ZWO2600MC and the Thousand Oaks filter on the Canon 5DM2 and 600mm Canon lens.

[OzEclipse]

An ND5 (100000x filter) has a nominal exposure of ISO100, 1/500s, f8.

Your exposure ISO200, f5.6, 1/320 sec and you are 9% below middle grey indicates you are closer to ND 5.6 (420000x) darker - that's a good thing!

Joe

I'll be honest, I'm not a huge fan of this Thousand Oaks filter. Prior to the annular eclipse last October I did back to back testing with it and the Baader ASTF filter and it produced a much sharper image.
I just can't spend money to buy another white-light filter right now and I'm using the only two I have. One Baader ASTF that will be running on my main scope with the ZWO2600MC and the Thousand Oaks filter on the Canon 5DM2 and 600mm Canon lens.

I bought two 500x1000mm sheets of Astrosolar filter material 20 years ago. Cost me about USD100 each. Our dollar was worth about USD0.52 at the time so it cost me A$410 + freight. One sheet was ND 5, the other was ND 3.8(for low altitude eclipses)

I still have plenty because the filter sheet holders and mounts I make, explained in my post in the 'Articles' section, protect the filter sheet really well so I haven't used or needed to replace nearly as much as I thought I would. Each filter has lasted decades. I have even sold some to friends locally.

They produce white or slightly magenta images. These can easily be false coloured in post to any hue I like. For example, all of these partials were captured white and coloured in post. I could as easily have made them more yellow or orange or left them as white. From memory, I picked up the colour from the yellow-orange haze on the horizon in the lower right hand corner. The colour is complimentary to the lovely blue hue of the sky. The lower redder images of the setting partial reddened themselves. I applied the same colour shift as the high ones but they had some extra colour that made the whole thing look pretty natural,even if I do say so myself.

Cheers

Joe

[AstroBee]

Joe,
Now I understand why your username is OzEclipse. That is one of the most spectacular eclipse composites I've ever seen!

I was talking with the CFO (wife) this morning and telling her about the eclipse and the trip we are making. She asked if there was anything I needed and I mentioned wishing I had another Baader filter. She told me to order it so I did.
So both rigs will be shooting with Baader ASTF filters.

[OzEclipse]

Thanks Greg,
I've had 15 eclipses to get it right
Here's the caption with tech info for that image. To colour the partial phases, I use layer blending, I place a layer of solid colour over the images then blend in either multiply or colour blend mode.



The Sun At Totality With Partial Phases At 3 Min Intervals.
The two stars in the upper right of the frame are Castor and Pollux while the fainter star at the 10 o'clock position is the 2nd magnitude double star Ahlena and above it to the left is 3,3 magnitude Alzirr and the in the 4:30 position is 3rd magnitude Mebsuta. In addition to the thirty-three partial eclipse images, five different exposures of totality were radially composited to show the corona from the limb out to approximately 5 solar radii from the limb. Fortunately, the two tiny clouds at bottom left were the only two clouds in the sky.

Partial eclipse image sequence:
Pentax K1 full frame DSLR. ISO100
50mm lens f 2.8 1/4000 s (equivalent to 1/1000 s @ f5.6)
Baader Astrosolar V5 solar filter.
1 exposure every 3 minutes for 2 hrs using intervalometer.


Total eclipse image sequence:
Solar filter removed 30s before totality
Pentax K1 full frame DSLR camera 50mm lens f 2.8 ISO 100
HDR composite combining 5 exposures ranging from 1/500 s to ¼ s
Processing: Adobe Lightroom & Photoshop

Cheers

Joe

[AstroBee]

I'm going to have a full frame dslr running with a 14mm wide angle lens just to capture the group and eclipse. I'll have that one un-manned running with an intervalometer probably every 10sec or so because I want to create a timelapse video of that when it's done.

[OzEclipse]

The trick that I didn’t explain in the caption was that I used a Y cable to splice two intervalometers into the camera. One intervalometer captured the 3 minute interval images the other drove the much faster hdr cadence during totality. User mode 1 was set to single exposure for the partial, user made 2 was set to 5 step 10 eV auto bracket. A minute or two before totality all I had to do was switch from user mode 1 to 2.

[AstroBee]

Very cool.
I'll be down in your neck of the woods July, 2028. My wife retires May 2028 so that's her retirement vacation celebration. That will be her first total eclipse. She's unable to travel with my in April because of college finals and she had just started a new job back in 2017 and couldn't take off for that one.

[OzEclipse]

Very cool.
I'll be down in your neck of the woods July, 2028. My wife retires May 2028 so that's her retirement vacation celebration. That will be her first total eclipse. She's unable to travel with my in April because of college finals and she had just started a new job back in 2017 and couldn't take off for that one.

Greg,
Excellent. Look forward to “crossing paths.” .
Joe

[AstroBee]

I just finished the solar quiz.

Reminded me that one of the "experiments" I plan on doing in April is making sure my Pegasus Astro UPBv2 is running and the temp sensor is recording/logging every 10 seconds. It will be interesting to see the temperature drop during totality.

[JSBach1801]

Have you considered a monopod for the 600mm lens? It can make a huge difference.

[AstroBee]

Have you considered a monopod for the 600mm lens? It can make a huge difference.

I've got a monopod and tripod that I use for the long lenses. On this particular day I was just being lazy and didn't want to pull out all that. I just needed to know the exposure at ISO200 f5.6 so the 300mm handheld gave me the data I needed.
On eclipse day the 600 will be on an iOptron ZEQ25 mount, tracking.