Review - Meade Instruments ETX-125 Observer Telescope, page 3
Posted: 24 May 2017
During the First Light session I imaged the planet Jupiter using the iPhone 6s Plus. I mounted the iPhone on the telescope using a Levenhuk Smartphone Adapter, as seen here:
I used the iOS app NightCap Camera (formerly NightCap Pro) for these images of Jupiter:
Jupiter and 4 Galilean Moons, afocal 73X
Jupiter, afocal 73X
Jupiter, afocal 196X
Jupiter and Great Red Spot, afocal 196X, stack of 319 video frames
When mounting the afocal adapter on the 9.7mm (196X) eyepiece I discovered a problem. The 9.7mm eyepiece included with the ETX-125 Observer telescope is much shorter than my older 9.7 eyepieces. There is very little room for the adapter to attach to the eyepiece tube. This resulted in the smartphone camera lens being far from the focal plane of the eyepiece and reducing the viewable FOV significantly. For small objects like the planets this is not major problem except when trying to get the camera and eyepiece optically aligned. However, this will be a serious drawback when imaging the Moon. You will probably want to use a different (i.e., longer tube) short focal length eyepiece when imaging lunar craters.
On a later session, with the ETX-125 Observer mounted in Polar mode, I took this image of M13 (Great Globular Cluster in Hercules) using the iPhone and NightCap Camera:
Tracking was not good enough for a long exposure and some trailing is evident in the image.
I also did some prime focus astrophotography tests using a D7200 DSLR, seen here mounted at the eyepiece port using a 1.25" prime focus adapter:
These images show the planet Jupiter:
Jupiter and 3 moons (full-frame):
Single frame image of Jupiter (cropped):
Stack of 132 video frames of Jupiter:
A Barlow Lens or Telenegative Lens will increase the focal length of the telescope for prime focus images. I will do some tests of that at a later date.
As with all previous ETX models from the first one in 1996, the ETX-125 Observer has a rear port where a SLR or DSLR can be attached using a Meade #64 T-Adapter. I had purchased one for my original ETX for use with a Pentax Spotmatic SLR. Using an appropriate T-Ring the adapter will work with any SLR or DSLR. Here you can see my Nikon D7200 DSLR mounted at the rear port with the ETX-125 Observer in Alt/Az and Polar Mode, with and without the adapter extension:
Several things complicate using a camera at the rear port. As you can see in the Alt/Az photos above, the maximum elevation will be limited to about 45° above the horizon before the camera touches the base. In Polar Mode you can reach the Zenith, but will be limited in how low you can go in elevation. The other issue with a camera at the rear port, especially heavy ones, is the severe out-of-balance condition. If you want to image with a camera at the rear port you should consider attaching a counterweight system (see the Helpful Information: Astrophotography page on "Weasner's Mighty ETX Site" for several counterweight tips). The telescope can be focused when using the T-Adapter with its extension and without it, so using the adapter without the extension can help somewhat with the out-of-balance condition. But I recommend that most imaging be done using a camera mounted at the eyepiece hole on top of the telescope tube.
These have just been some initial astrophotography tests. I will do additional astrophotography with the ETX-125 Observer and report on those on my regular Cassiopeia Observatory reports.
The ETX-125 Observer telescope continues the well-deserved highly praised legacy of the Meade ETX line of telescopes that began in 1996. The optical performance will provide amazing views to both the new user and the highly experienced amateur astronomer. The ease of set up and use will be greatly appreciated by the new user. The "Astronomer Inside" audio narrations will help the new user learn about objects in the Universe and will be handy at star parties.
If you are looking for an excellent first telescope or a small portable telescope for use at star parties or a grab-n-go telescope to complement your other telescopes, the ETX-125 Observer is an easy telescope to recommend.
Comments are welcome using Email.
Copyright ©2017 Michael L. Weasner / firstname.lastname@example.org
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