Category Archives: Venus Transit
Brace Yourself, The Venus Transit is Coming!
Yes that’s right! A little over 24 hours remain until the most spectacular astronomical event of the year! However, make sure you check the weather forecast for your area before venturing out to watch the transit. The entire east coast and much of the southeast of the USA could be blanketed by showers and overcast skies most of the day tomorrow. If you’ve been building up your excitement for the past several months like I have, start to release that excitement because there is a strong possibility that as much as 75 percent of the country won’t be able to see the transit due to bad weather. Even though the transit is over 24 hours away, as I watch the grey clouds roll in I’m beginning to get that deflating feeling like I had a Venus-sized balloon of excitement for the transit and now someone is rapidly letting all the air out of that balloon.
Rain or shine I’m going to be watching the weather minute by minute to find out what’s going on. Don’t abandon your plans quite yet. You really never know with the weather. There may be a break in the clouds long enough to watch the ingress of the planet. Regardless, I tested my homemade solar filter yesterday morning and I must say that it works to perfection! I opted to make one myself instead of buying an expensive one from a vendor. I used the visual density Baader Solar film from Astro-Physics and constructed a housing for it.
DIY solar filter success
The resulting image was spectacular! Even though it was hard to get a full image of the sun on my phone’s camera I could still see it perfectly through the 25mm eyepiece. I suspect it has something to do with the fact that the aperture is now offset and a lot smaller than the normal aperture. A great deal of detail could be seen on the sun such as sunspots 1497, 1496, 1493, and 1494, as well as a strange black smudge near the center of the disk which I’m not sure about. The resulting image is much dimmer than the sun funnel technique and I think provides much better contrast on the surface for defining sunspots. Regardless of whether I can view the transit, I’m very pleased with my filter and hope to get lots of use out of it. Heck, I only used a small bit of the Baader film so I can make more if I want!
Partial image of the sun’s disk
My fingers are crossed for good weather and if you’re planning on viewing the transit best of luck to you as well! Clear skies!
The Sun Funnel
In preparation for the upcoming Venus transit on June 5th I was looking at cheap, but effective ways to view the sun with my telescope. I wasn’t very interested in buying a full aperture solar filter for my 10″ scope so I was thrilled when I found www.transitofvenus.nl. The accessory proposed on this site is the sun funnel, a rear projection, group viewing tool for the viewing the sun. The sun funnel is very easy to make and costs just about $20 to make.
The funnel consists of a large fuel funnel, rear projection screen, two hose clamps, and an eyepiece. I say it costs about $20 assuming that you own a telescope eyepiece already, if not you’ll have to pay a bit more. You don’t need an expensive eyepiece, just one that fits the focal length of the telescope and the length of the funnel to give you an optimal image size. More info on the eyepiece can be found on the website. The rear projection screen can easily be ordered online and costs about $17 for one square foot.
I put my sun funnel together this past Monday and attached it to my scope but alas, the sun had almost set and was behind the trees in my backyard. I had to wait until Friday evening after work to get another good viewing chance, but I was not disappointed! Once the image is focused correctly my 25mm eyepiece projected an image about 75% of the funnel’s diameter! The image is still rather bright, but is by all means safe to look at with the naked eye (although sunglasses might make it more comfortable).
EDIT: I would also highly recommend building an aperture stop of some sort to reduce the amount of light gathered by the scope. You can use any kind of material really, but all you do is cut out a circle about 2″ in diameter in whatever material you’re using (a cardboard box works well) offset from the center so that you don’t cover up the secondary mirror (for reflectors). This reduces the aperture of your scope from say 10″ to 2″ which is perfectly fine for viewing an object as bright as the sun.
Once set up the image of the projected sun is razor sharp! As the picture below shows, once the image is focused on my phone the detail on the disk is stunning! Several sunspots are visible dotting the fiery surface of the star. In the center left and clearly visible is the large sunspot 1459. Three other pairs of sunspots form an isosceles triangle around 1459 in the center. Not bad for my first attempt at viewing the sun. I’m really looking forward to viewing the transit through the sun funnel in less than two months!
Focused image with sunspots visible
