#explore scientific

Explore Scientific ED127 Air-Spaced Triplet Refractor Telescope

Shop the ED127 refractor telescope featuring air-spaced triplet optics, precision focusing, and exceptional clarity for deep-sky observing and imaging.

Explore Scientific ED127 Air-Spaced Triplet Refractor Telescope

Shop the ED127 refractor telescope featuring air-spaced triplet optics, precision focusing, and exceptional clarity for deep-sky observing and imaging.

Explore Scientific ED 80 Classic White Essential Series f/6 Air Spaced Triplet ES-ED0806-01

Explore Scientific ED 80 Classic White Essential Series f/6 Air Spaced Triplet ES-ED0806-01 is a great product. The telescope we need has two factors : high-quality optics and a steady, smoothly working mount. And all other things being equal, big scopes show more and are easier to use than small ones, as we’ll see below. The easiest way just only acquiring this outstanding Explore Scientific ED…

Viewing of the red planet has been excellent recently. Mars was in opposition at the beginning of March, that is, the Earth was in between Mars and the Sun, allowing us to see the entire illuminated face of the planet. If you think about the geometry, this also means that Mars will be very high in the sky in the middle of our night. Viewing is better when objects are higher in the sky, because the light needs to travel through less interfering atmosphere.

"Air mass" is this distance through the atmosphere that the light must travel from a celestial object. It is defined as a relative measure, with an air mass of 1 being the atmospheric thickness when standing at sea level and viewing an object at zenith (directly overhead). The lower the air mass, the better the view. Air mass can be less than 1 when viewing from elevation. Air mass when viewing at the horizon is a whopping 38!

The sky was very clear around sunset, so I set my 8" reflector out to cool. After dinner, I saw some thin clouds hovering near the horizon, so I got everything set up as fast as possible. I usually don't use the cooling fan on my big scope. This is dumb, because it can improve viewing tremendously, but I haven't done that much planetary viewing to date, so it hasn't seemed that important.

I wanted to try out the new eyepiece that I got today, an Explore Scientific 6.7mm 82 degreee. This is a huge improvement over my previously highest magnification EP, which is the generic Zhumell 9mm plossl that came with my scope. That EP has an AFOV (apparent field of view) of only 40 degrees. Here's how the math stacks up with the two EPs in my 1200mm scope using a 2x barlow:

ES 6.7: 1200 / 6.7 x2 = 358x magnification

TrueTelescopic* field of view = 82 degrees / 358 mag = 0.23 degrees.

9mm Plossl: 1200/9 x2 = 267x magnification

TFOV = 40 degrees/267 = 0.15 degrees

So the ES 6.7 gives 34% more magnification and an improvement in FOV of 50%. Nice!

The combination of a properly cooled scope, Mars above 80 degrees elevation, and the new EP was fantastic. I was able to see the polar ice cap, small and well defined, as well as darker markings, a narrower lateral band in the southern hemisphere and the larger dark field in the north. The ES 6.7mm itself was great. The image was equally sharp all the way across the field and the field of view was so big that it was very easy to keep the planet in view, even at high magnification with my driveless dobsonian mount. The view was so wide, I almost felt like I had to look around the corner to see the field stop (narrowest part of the EP).

I also compared the vanilla view with the aperture mask I made, and with an 80A blue filter. I enjoyed the view with the blue filter the most. With the aperture mask was okay, but not as clear. It might just have been my poor design for the mask. I may have to mess with it a bit more. I may experiment with some other colored filters.

Unfortunately, I only got about an hour of viewing in before the clouds rolled in.

On another evening, I am going to try out the ES 6.7mm on my ED80 "grab & go" scope. The 9mm plossl doesn't provide enough magnification to see much of Mars, at least not with my middle-aged eyes. Hopefully, the ES 6.7 will do better.

Overall, I very satisfying session, if a little short.