Category Archives: Astronomy

West Point visits the Kuhn

On December 26, 2015 The Orange County Astronomers had some visitors from the West Point Military Academy. They stopped by to see the club’s 22inch telescope, known as the Kuhn Telescope. They were being hosted by Pat Knoll, Ralph Emerson, and Trey Mcgriff, who helped install a telescope setup at West Point. Here is a portrait of the group  beside the Kuhn Telescope. Dr. Paula Fekete is shown at the telescope eyepiece.

Some visitors from West Point Military Academy at the OCA Kuhn TelescopeAfter posing for this shot we took a VR panorama, click on the image below to view a larger version, you can also expand it to the full size of your screen. Click and drag in the scene to scroll around.  Even though it was a cold and very windy evening, we had a good time.

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NGC 2264 – Cone Nebula and region

Here is an image that has taken me awhile to get around to finally processing. It is of NGC 2264 and the Cone Nebula region. Also known as the Christmas Tree cluster it is located in the constellation Monoceros, about 2,700 light years from Earth. This image was taken over 3 nights with a total exposure time of 9.5 hours through color filters. Of which 4.5 hours was for Luminance, and 100 minutes each for Red, Green, and Blue, exposure was 10 minutes long. The camera was a cooled CCD camera made by QSI, the QSI 583ws model. The telescope used was a Borg 125SD, 5 inch refractor at f6.4, for a focal length of about 800mm. The images were then calibrated and stacked together to make the final color image.

Enjoy.

NGC 2264 - Cone Nebula and region

 

Update on the Rokinon 12mm f2 NCS CS lens

A brief update on the Rokinon 12mm lens that I previously reviewed. I did get another copy of the lens and color cast that I saw in the previous lens was gone. So that is great news. I have shot with the lens some more including getting out and shooting under the stars. One of the main reasons I was interested in this lens was it might make a good lens for nightscapes. I have to say that it really does make for a good lens for night shots. The lens is still a bit soft at f2, but that is to be expected with a lens that is this wide. It is not to say that it is unusable, but it does perform better stopped down. If there is nothing close to the lens and most items are at infinity focus then it is hard to see the softness.  For most instances this not a problem and it is a wonderfully fast lens. I found that stopping down to f2.4 or f2.8 resulted in a general improvement, and by f4 is pretty good all over. That being said for quick nightscapes the faster aspects can be beneficial, and it will show less trailing. Even though this is a wide lens, with the crop factor it does give the field of view of an 18mm lens so that means that stars will start to show trailing before 30seconds, depending on where you point the camera.

This shot was from a quick trip out to Joshua Tree National Park, taken with a Fuji X-T1 and the Rokinon 12mm at f2.0 and ISO 3200, single exposure of 30 seconds.

Milky Way over Joshua Tree NP

Milky Way over Joshua Tree NP

The lens is a good deal considering the price and the performance. The downsides are the full manual focus and aperture and the lack of details being recorded in the EXIF of the camera. The Fuji does allow the setting the focal length so that is recorded, however the aperture used is not recorded. The lens hood also leaves something to be desired. It is really loose fitting and will sort of snap into place but there is a lot of play and I have found that it has come off sometimes in the camera bag, poor design, in my opinion. It is a functional hood for the wide angle lens but it could be better. The positives pretty outweigh the negatives. There is little chromatic aberration and little coma in the corners. I do expect some in a lens this wide but it is very negligible. Color and contrast are quite good. It has well corrected optics, much better than one would assume with a lens of this price point. It is also compact and relatively small for a wide angle lens. Focus ring and aperture ring are smooth and have a good feel to them. The aperture ring is detented at half f-stops from f2-f22. The lens feels solid and well constructed and is not weather resistant. The front is threaded for 67mm filters, which is nice.

I would recommend this lens, especially for the price point.  I would give the Fuji 14mm f2.8 lens the edge, it has the full autofocus, as well as manual focus and the ability to have auto aperture, but the Fuji is substantially more money. The Rokinon is a bargain and for me a nice lens to have in the bag and one that will get used, for nightscapes and landscapes. I will still keep my Fuji 14mm. The Fuji is a bit better corrected optically but the Rokinon does pretty well. The extra 2mm of the Rokinon does make a difference. I was also interested in the Rokinon 10mm but it is twice the weight of the 12mm and is not as appealing. The 12mm was designed for mirrorless cameras and therefore the size and weight are scaled accordingly, while the Rokinon 10mm appears to be a verison of their DSLR lens with a Fuji X-mount on the end, not as appealing. I am happy enough with this Rokinon that I do not feel the need to compare it to the Zeiss 12mm lens for Fuji.  For ultra wide I will stick with the Fuji 10-24mm f4.

Image of the week #26

Hard to believe half the year has gone by, I guess that is the sign of getting older, time flies! Here is this week’s image, it was more an experiment but I like how it came out. I got an adapter for my Fuji X-Pro 1 to use my Canon lenses, so this is taken near Temecula with the X-Pro 1 and a Samyang 14mm f2.8 lens, taken at f2.8 and a 30 second exposure at ISO1600. I thought it turned out pretty well, the yellowish glow in the bottom right is the light pollution dome from San Diego. The summer Milky Way always a neat thing to see. Enjoy.

 

Venus Transit

Here are some images from the Venus transit, which occurred on June 5, 2012. These were taken from Santa Ana, CA on the top level of a parking structure. I used my Canon 1D M4 with a 100-400mm at 400mm and a 1.4x which gave me a focal length of  560mm, these are crops of the image, taken using a solar filter. You can see several sunspots in addition to Venus as it moved across the face of the sun. These were taken over a period of about 3 hours. Hope you enjoy them, click on the images to see larger versions.

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Image of the week #20

This weeks images are of the partial annular solar eclipse. Taken with a Canon 1Dm4 and 100-400mm lens at 400mm and a 1.4x extender.  These shots will be part of a timelapse movie of the sequence. Also included is shot of the camera setup that was used to take the solar images. This setup will track the motion of the earth so that the sun always stayed in the frame as it was going down towards the horizon. The marks on the surface of the sun are sun spots. From the location, east of Temecula, the sun went down below the horizon as it was coming out of being eclipsed, the last shot is more red because the sun was right on the horizon and I should have increased the exposure and you can also see some of the brush on the horizon as the sun was setting. The eclipse occurred on May 20, 2012.

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Image of the week #11

The summer Milky Way over the Sierra Nevada from the Alabama Hills, this image was taken last August but I finally got around to processing it. This is a single image taken with a Samyang 14mm f2.8 lens at f2.8 and ISO 3200 with a Canon 5Dm2. The moon had just risen up behind me and that is what illuminated the foreground and the mountain range, this 30 second exposure makes it look like daylight, almost. The Alabama Hills is a nice place to visit and is a familiar backdrop for a lot of Hollywood movies. This is located just outside Lone Pine, CA and in the mountain range to the right of the center of the image is Mt. Whitney, the highest peak in the Continental United States. The image turned out a lot better than I thought it would so I am pretty happy with it. Hope you enjoy it also.

 

 

Lunar Eclipse

Early Saturday morning, December 10, 2011 there was a full lunar eclipse. Here on the west coast we only got to see a portion of the lunar eclipse, it started just before 5AM and the moon was going to set at 6:30AM, but we lost sight of it before then due to a layer of clouds low on the horizon. This was tricky to photograph, as the exposures kept changing due to the moon going into the Earth’s shadow, so it got dimmer and dimmer, complicating matters was the sun was also rising, so the background got brighter and brighter. This first shot is a composite of 23 shots with a 50mm lens. Exposures ranged from 1/200 to 2 seconds at f5.6 at 100ISO. It was also a challenge to composite as the images ranged from a black sky to a much brighter blue sky as the sun got higher.  (Click on the images to see larger versions.)

 

This next shot is a composite of 3 shots taken with a 500mm lens, this shows the shadow moving across the face of the moon. The orange color is when the shadow is covering the moon, almost completely here, since the moon was full it was also very bright, so you need to choose what to expose for, the shadows or the brightly lit areas. The problem with bracketing and making a composite exposure is that there is huge dynamic range, so you would need a lot of exposures. Also the moon is moving constantly so you will get some shifting in the frame, but that can be dealt with, however the real problem is the length of exposure to show the details in the dim areas is so long that the moon is blurred unless you track the movement of the moon.

These were shot from Laguna Beach, it was an interesting experience and I would probably shoot things a little different next time, but overall I did ok. I would shoot at a higher ISO for the composite sequence and check exposures more often to equalize the relative exposure of the moon. I would also use a slighter longer focal length.  For the longer focal length shots, a higher ISO would give me a faster shutter speed and less chance for showing movement blurs and I would also make sure the image stabilization was off for this type of photography. Thanks for looking, feel free to comment.

Star Trails

An image of star trails taken in the Alabama Hills in the Eastern Sierra. The curved star trails are the edges closer to the two poles, and in the center the trails are more or less straight the closer to the ecliptic plane. This is a stack of 99 exposures of 30 seconds each using a 14mm f2.8 at f2.8. Towards the end of the run the moon was coming up and that is what illuminated the mountain range. The tall peak just to the left of center is Lone Pine Peak, and off to the right slightly of center is Mt. Whitney. Mt Whitney is actually a taller peak but it is further back in distance relative to where I took the images. The lights down at the bottom just right of center is the Mt. Whitney Portal area, Mt. Whitney is just above those lights.

 

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IC 4603

IC 4603 is reflection nebula in Ophiuchus. This is a very colorful area of the Milky Way, this reflection nebula is surrounded by dark nebula,  which is gas too dense to let light pass through. Taken with a cooled ccd camera, a QSI583wsg and a Borg 125mm f3.8 refractor. This combination yields an effective focal length of 484mm. This is a total of about 3 hours of exposure time, the monochrome images are taken through color filters and then calibrated and stacked to produce the color image. Taken on the night of June 4, 2011, near the town of Anza, CA.

 

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