Category: Afocal


Shown above is an image of last year’s Supermoon taken through afocal method with a 6-in reflector and a mobile phone camera. Photo Credit: Cristina Flores

This month’s full moon is the largest full moon of the year! :)

What Time to Observe

There is much confusion on the Internet as to what time this “Super Moon” thing would occur. According to a lunar calculator from the NASA website, the “Full Moon” should occur on May 6, 3:36 am Universal Time, this Sunday. In local time (Philippines), there would be an additional 8 hours due to the differences in time zones, thus, in the Philippines, the precise moment will occur at “2012 May 6 3:36 UT” + “8 hours” = 11:36 am May 6 (near noontime). Unfortunately, 11:30 am is a daytime here in the Philippines, thus, the moon will not be visible. To be able to observe it, either you observe tonight, just a few hours before sunrise, or later tomorrow, a few hours right after sunset.

To calculate for your local time, just add or subtract the correct time difference. In the given example, I used +8. Just substitute it and do the math :) Hope it answers some of the confusion.

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The modification involves physically removing the “hot plate”, a kind of filter that blocks infrared light. Manufacturers install it in cameras in order to correct for the reddish hue inherent to CCD or CMOS sensors. Removing such filter makes the camera more sensitive to IR and as well as H-alpha wavelengths, which is particularly useful in deep-sky photography.

Canon S3IS point-and-shoot camera modified for astrophotography (afocal imaging)

Read more.

Barlow lenses may be used to magnify images in casual visual observation and also astrophotograpy (afocal, prime focus, or eyepiece projection)

I find Barlow lenses very useful in achieving better image scale in planetary imaging (through afocal, prime focus, or eyepiece projection). Using a 2x Barlow lens, I can actually double the effective focal length of my setup. With a 2x Barlow, the effective focal length of my 900 mm telescope would  then be equal to 900 mm X 2 = 1800 mm.  During nights of steady seeing and I wish to further magnify an image, I use another 2x Barlow, thereby having an effective focal length of 900 mm X 2 X 2 = 3600 mm :)

For featured photos, click here.
For tutorials on how to get started with astrophotography, click here.
For DIY astronomy projects useful for astrophotography, click here.
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© Anthony Urbano (Manila, Philippines)

Another reprocessed Saturn image. I figured the best way to learn post-processing is to experiment with different settings/parameter using the same avi file. :)

Image taken through afocal method using a Canon S3iS and a 4-in f/9 refractor

Image of Saturn last January 31, 2012 taken afocally using a 4-in f/9 refractor with 32 mm eyepiece and a Canon S3IS

The data used to produce this image of Saturn was acquired last week. It was only now that I was able to process it. This image was taken afocally with a 4-in f/9 refractor and a Canon PowerShot S3IS in video mode. The avi was then processed using RegiStax to produce this final image. More Saturn images here.

By placing a point-and-shoot camera in close proximity to the eyepiece of a telescope, it is possible to capture an image of M42 like the one shown below. Now, who says point-and-shoot cannot be used for imaging deep-sky objects?

Image of Orion Nebula taken with a point-and-shoot camera through afocal projection with a 4-inch f/9 refractor. For more images of Orion Nebula, click here.

 

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