Dale Ghent | May 5, 2008
I took this photo of the 1st half Moon while at the April 10 HAL star party at Alpha Ridge Park, Maryland.
Although I’ve taken many photos through my telescopes, I really consider this one to be my first “real” astrophoto, having gone through the motions of equipment setup, settings selections, and a bit of post-processing in Photoshop CS3 for this one shot of the moon.
These two books – Michael Covington’s Digital SLR Astrophotography and R. Scott Ireland’s Photoshop Astronomy – lent me a big hand in teaching me what to do before and after taking a photo or series of photos of an object. I highly recommend them.
Dale Ghent | January 7, 2008
I’ve been really quiet with the astronomy-related blog posts over the past year, but that doesn’t mean that I’ve been straying from the hobby of amateur astronomy – far from it. I’ve signed up with two local clubs and have been brining my scopes out to star parties (or just my back yard) whenever I can.
Up until recently my only two telescopes have been a Orion XT10i, a 10″ dobsonian, and a Coronado PST for viewing the Sun in Hydrogen-alpha wavelengths. This past holiday I treated myself to a new scope, a 90mm apochromatic doublet refractor made by William Optics (WO) named the Megrez 90.
The Megrez 90, as the name implies, is a high-quality refractor telescope that uses calcium fluoride optics. The objective lens is 90mm in diameter and the scope has a focal length of 621mm, which means it has a focal ratio of f/6.9. When WO brought this scope to market, it took it by storm as it was quickly regarded as a high quality instrument at an astonishingly low price, easily comparable in optical quality, fit and finish to long-standing fonts of quality such as TeleVue and Stellarvue.
I found the reviewers to be spot-on with their assessment of this telescope’s construction and features. Its dual-speed (10:1) Crayford-style focuser has made me wish I had it on my big Orion XT10i. The stars are beautiful pinpoints with no detectable (to me at least) chromatic aberration. I have only spent a few nights outside with this ’scope so I don’t have a full feel of its capabilities… more on that later. But I will say that I have been impressed so far and would at least offer it as a suggestion to anyone who is looking for a telescope in its class.
Along with the telescope, I purchased WO’s EZTouch alt/az mount and wooden surveyor’s style tripod to put it on, as well as their Red Dot Finder instead of a classic finder scope. I found with my XT10i+Telerad that I prefer to star-hop to my target rather than bungle around inside a restricted FOV.
I foresee many nights out under clear skies with this fine instrument.
Technorati Tags: astronomy, refractors, telescopes, william optics
Dale Ghent | January 20, 2007
Another post card from the Cassini probe from a far-off corner of our solar system. There’s always beauty in the blackness, I tell you.
This psychedelic view of Saturn and its rings is a composite made from images taken with the Cassini spacecraft wide-angle camera using spectral filters sensitive to wavelengths of infrared light centered at 728, 752 and 890 nanometers.
NASA Photojournal Entry
Technorati Tags: saturn, cassini, exploration
Dale Ghent | April 5, 2006
I fixed my gallery and uploaded the pictures that Talia and I took this past week as we travelled around Turkey.
We started out in Istanbul in the old city, then we went on to the Antalya area of southern Turkey to attend the Soulclipse Festival near the small town of SaÄŸrin. There, we camped out in a beautiful rural area, danced day and night, and got to experience a total solar eclipse on the 29th. Since we rented a car, we were able to leave the festival a few times and explore the surrounding region… Climbing up high mountains, playing on golden beaches, and exploring the ruins of a Roman city are among the things we did.
So, without further ado, here are pictures of Istanbul, Soulclipse and other places.
In a separate photo album, my solar eclipse pictures, taken through my solar telescope equipped with a Hydrogen-alpha bandpass filter. Zoom in on them and you’ll see tiny solar prominences.
Technorati Tags: soulclipse, eclipse, psytrance, turkey, istanbul, astronomy
Dale Ghent | March 23, 2006
I just received from Scopetronix the camera adaptor ring and mount to mate my Sony DSC-V1 camera to my Coronado Filters P.S.T. Naturally, I had to use it as soon as possible. I waited for a nice break in the overcast and was able to snap this picture of the Sun:
Full Size (800×600)
This first run made me realize that I need to come up with a good workflow to get the focus and exposure right, as well as tune the filter on the P.S.T. to get desired results.
The eyepiece used for this photo was a 7mm Tele Vue Nagler Type 6.
I really wish that I had a D-SLR camera.
Technorati Tags: Astronomy, Astrophotography
Dale Ghent | March 21, 2006
Last week I purchased a Coronado Filters Personal Solar Telescope. This telescope is made specificially for sun viewing and incorporates a filter that bandpasses the hydrogen-Î± wavelength, allowing clear views of the sun’s chromosphere.
Dale Ghent |
I made an eclipse simulation video of the upcoming solar eclipse as it will be seen from the SoulClipse Festival in Turkey next week.
It’s in H.264 format and shows the eclipse as it will be seen from the ground and from orbit over Turkey. It was made with Starry Night Pro 5.8.2.
Technorati Tags: Astronomy, Solar Eclipse
Dale Ghent | October 28, 2005
There are two prominent planets in the night sky this fall season, both of them very easy to spot with the naked eye.
As the sun sets in the south west, you’ll notice a very bright “star” hovering about 2 fist-widths above the horizon. This is Venus. Venus is so bright that on a very clear day and with a keen eye, you can even see it in the mid to late afternoon.
Wait a few more hours, closer to midnight, and look up in the east-north-east sky. You’ll notice another bright “star” which stands out from the rest and that it has a orange-like hue to it. This is Mars.
Dale Ghent | January 12, 2005
Want to see a comet?
Alright, here's how.
Around 8:30pm, go outside and look at the west-southwest horizon. Look almost 90Â° upwards (okay, 81Â° to be exact)
You're now looking at comet Machholz C/2004 Q2.
This comet will be rising in the south eastern sky before nightfall and make its way to the north western sky where it sets around 4am. 8:30pm is when it'll be directly overhead.
If you have binoculars, you'll have a great view of it, but you can see it with the naked eye if you don't have any.
Dale Ghent |
Law of Universal Gravitation
Every object in the Universe attracts every other object with a force directed along the line of centers for the two objects that is proportional to the product of their masses and inversely proportional to the square of the separation between the two objects.
God I love science when I'm dr0nk
now for Hubble's Law which tells us the expansion of the universe is smooth. This relates to the expansion of galaxies.
V = Ho D
Recessional velocity that we observe agalaxy (ie: moving away from us)
Hubble's Constant (around 70km/second per megaparsec) (There is some debate in the community whether this is the true value for all cases)
Distance to the obseved galaxy in megaparsecs
Remember a parsec is about 19,173,560,000,000 miles, which is also means a metric fuckton of gas money.
So if we see a galaxy with a recessional velocity (compared to us) at 5000000mph, that is 0.00745582 the speed of light.
Lets divide that by Hubble's Law (Constant) of 70km/s per Mpc and we get 31.95 Megaparsecs, which is equal to 104.22 million light years. That galaxy is 104.22 MILLION light years away.