Sunspots - 16th May

Michael,

If I were in your place, I would choose the greater size version. Not only does the greater focal length mean easier focusing but you will also be better suited for capturing, for example, the black-drop effect.

Full disk images are nice but Venus will be around 1/32nd of the diameter of the sun, from what I recall, which means a full disk image will do injustice to Venus. Add a half-decent sunspot or two in the area and everyone will be asking where/who is Venus.

Anthony.

Anthony,

Thanks for that. I do find focusing very difficult. As you pointed out, at longer focal lengths it should be easier, especially if there's a sunspot. It'd give me something to focus onto prior to the start of the transit.

Let's just hope the weather will co-operate!!!

Michael

Assuming the weather is good, and unfortunately that's a HUGE if, then you should be able to use a waning gibbous moon to focus. I actually plan on getting on site while it's still dark, aligning the goto, and spending soom time checking the moon out. That's if all goes to plan.

Michael/Shane,

I often find the edge of the moon or sun to be a great means to nailing good focus. Now, if you have something like a split-screen focusing mirror in your camera (or knife-edge focuser), the edge will get you perfect focus in seconds.

Anthony.

Hi All,
Great to see fierce activity here
BTW, Mercury will also be just above the horison a small while before sunrise, or is this asking for too much ??, Anyway like all you lads, I've been practicing with telescopes/camera combinations.

The first pic is wiht the 12" and a full aperture solar filter and a canoneos 300D. For the transit, this does not appear to be the way to go as like what was said earlier, Venus will look like a sunspot !!



homepage.eircom.net/%7Esac/graphics/sun/sunvis_180504.jpg
I deliberately used low quality images, otherwise I'll end up with literaly gigabytes of pics on the harddrive and spend the next year processing them, the webcam would be better here and give a more magnified image, just like with the planets. This next pic was taken at the same time through a 70 mm solarmax h-alpha scope and the webcam, which I'm "testing" until the next Whirlpool start party. :lol: :lol:

I've tinted this a yellow colour, just to be different.



homepage.eircom.net/%7Esac/graphics/sun/...ha_yellow_lowres.jpg
So the question is, would you use the h-alpha scope or white light scope, or is that a stupid question??, maybe use both !!, but even if I bought another webcam, I dont think the laptop could handle it, or could it ??, has anyone tried this ???

Either way, I think the canon may not be the best camera for the transit, webcams rule

So the question is, would you use the h-alpha scope or white light scope, or is that a stupid question??, maybe use both !!, but even if I bought another webcam, I dont think the laptop could handle it, or could it ??, has anyone tried this ???

I presume from the resounding silence that the answer is NO.
I'll just have to try it with a friends webcam