ES 82 degrees 30mm

[Dave scutt]

Last night was the first clear night in a while, at 11.15pm it still wasn't dark I could only see Vega and Arcturus.

It was the first time using yhe ES 82 degrees 30mm and its a beast weighing in at 1kg I thought I would have had balanced issues but the dob moved around perfectly .

 

I didn't have much time to explore as I  had an early start in the morning so stayed around Vega, I've been using the skywatcher 28mm since I've got the dob and was I in for a treat, I could see so much more with the 30mm stars where sharp but not to the very edge of the fov.

It was so much easier finding objects with such a large fov I just pointed in that area moved around a bit  and it was there,  I moped up all the Open Clusters and Globular Clusters in that area, the ring and owl nebula,  then m81 m82 and then m51, noticed on my phone there was a comet  c/2017 k2  I've never seen a comet before tried searching for a while didn't know what I would expect to see  (something like a photo) but had no luck finding it. 

It was a lot easier holding my phone over the ep for photo's and took this one of m13.

Dave

Edited May 28, 2022 by Dave scutt

[cloudsweeper]

A beast indeed.  I too have no balancing problems with it.  (The big bearings on the Bresser Dob help there!)

It's my heaviest EP, followed closely by the OVL Myriad MWA 20/100 at 848g.  The Myriad however is longer......

Doug.

[Don Pensack]

14 hours ago, Dave scutt said:

Last night was the first clear night in a while, at 11.15pm it still wasn't dark I could only see Vega and Arcturus.

It was the first time using yhe ES 82 degrees 30mm and its a beast weighing in at 1kg I thought I would have had balanced issues but the dob moved around perfectly .

 

I didn't have much time to explore as I  had an early start in the morning so stayed around Vega, I've been using the skywatcher 28mm since I've got the dob and was I in for a treat, I could see so much more with the 30mm stars where sharp but not to the very edge of the fov.

It was so much easier finding objects with such a large fov I just pointed in that area moved around a bit  and it was there,  I moped up all the Open Clusters and Globular Clusters in that area, the ring and owl nebula,  then m81 m82 and then m51, noticed on my phone there was a comet  c/2017 k2  I've never seen a comet before tried searching for a while didn't know what I would expect to see  (something like a photo) but had no luck finding it. 

It was a lot easier holding my phone over the ep for photo's and took this one of m13.

Dave

Oof.  Bad seeing.

The "not sharp at the edge" could be coma, and the eyepiece has a tiny bit of unresolved astigmatism near the edge as well.  You don't say whether you are using a coma corrector in the dob or not.

Good luck finding the comet.

https://en.wikipedia.org/wiki/C/2017_K2_(PanSTARRS)#/media/File:C2017_K2_skypath.png

It's a tiny fuzzy star at the moment.

Here is the ephemeris:

https://in-the-sky.org/ephemeris.php?objtxt=ck17k020

Your best bet is to plot it on an atlas so you can find it easily by star hopping from a nearby naked eye star.

If you have a computer atlas, you can print the page where it is and mark it in.

[mdstuart]

I just looked at the comet in my 8 inch dob. It's only a faint blob at the moment. It would be easy to miss unless you know where to look exactly. As above plot it on an atlas and have another go.

Mark

[Louis D]

3 hours ago, Don Pensack said:

The "not sharp at the edge" could be coma, and the eyepiece has a tiny bit of unresolved astigmatism near the edge as well.

I've noticed the red and blue ends of the spectrum don't focus at the same point radially in my 30mm ES-82.  On Jupiter, I could literally see fully separated red and blue versions at the edge.  I was mystified why there were no other color versions in between, though.  The 30mm APM UFF does not suffer from this artifact.

[Don Pensack]

12 hours ago, Louis D said:

I've noticed the red and blue ends of the spectrum don't focus at the same point radially in my 30mm ES-82.  On Jupiter, I could literally see fully separated red and blue versions at the edge.  I was mystified why there were no other color versions in between, though.  The 30mm APM UFF does not suffer from this artifact.

6 elements versus 9 elements.

And 82° versus 70°.

But, you make a strong argument in favor of the APM.

That is one of many reasons I use that eyepiece for my lowest power.

[Carl Au]

On 29/05/2022 at 16:16, Don Pensack said:

6 elements versus 9 elements.

And 82° versus 70°.

But, you make a strong argument in favor of the APM.

That is one of many reasons I use that eyepiece for my lowest power.

They certainly are very popular in the states, you must sell a lot of them...

[Piero]

I had an ES 30mm 82 a few years ago. Mine was picked up in the second hand market for a bargain price. In my SkyWatcher 8" f6, it showed some astigmatism near the edge (I did not use a coma corrector with that telescope, so coma was also visible) and it certainly required a counterweight near the bottom of the tube.

It was a good eyepiece particularly given the ridiculous price I paid for it.

Following the selling of my ES 30mm 82mm, I tried 35mm Panoptic, 40mm MaxVision, 42mm Vixen LVW and the small eyepieces 30mm Vixen NLV and 32mm TV Plossl, before trying the 30mm APM UFF. The APM is my favourite eyepiece with a focal length >= 30mm based on optics, FOV, ergonomics, mechanics, weight and shape. The 30mm APM UFF delivers clean views to the edge even at F4 with PC2.