Category Archives: nightscapes

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.

[pano file=”wp-visit/wp-visit.htm” preview=”wp-visit/WP_p1.jpg” ]

 


 

 

 

 

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.