Quote:

---

Don,

Quote:

---

1) The C6 has about a 25mm opening in the back of the baffle. It's best with 1.25" eyepieces, but as long as you keep the field stop diameter smaller than, say, 30mm, vignetting shouldn't be too severe.

---

I had read on CN that the baffle is 28mm. But I measured the opening of my new C6 myself before I read your post, and it is about 25mm, or 1 inch. A good 1.25" eyepiece for low power would be my Ultrascopic 35mm, which would give me about 43x, 1.2 degrees TFOV, and 3.5mm exit pupil. It has a 29mm field stop, right below the 30mm limit that you suggested.

I don't plan on viewing everything - the big and the small - with my C6. I never really believed that SCTs are Jack-of-all-trade telescopes. I have other scopes and binos that I use for wide field. I wanted the C6 for views of the Moon, planets, the brighter DSO and double stars. Not every scope I own needs to give me a wide view of the Pleiades. But this one should show the Double Cluster well enough.

The C6 appears light enough that I can take it out for grab-n-go beside my house, or even backpack it for a 20 minute walk to a nearby site away from the neighborhood glare.

Mike

---

That eyepiece yields 1.09 degrees. It's no accident the 5, the 6 and the 8 all have about a 1 degree low power view. This was considered the "standard" low power view for backyard telescopes a generation ago. We have proliferated our approaches so greatly since then that you can now buy amateur, backyard scopes with low power fields of view as large as 5 degrees or as small as 0.5 degrees maximum field. We live in amazing times, where amateur astronomy is concerned.

Post Extras:

Quote:

---

4) These star diagonals may have a misaligned mirror. To test that, if you don't know how to do it off the scope, make sure your SCT is well collimated with a 10mm eyepiece straight through (no diagonal in place).
In the northern hemisphere, Polaris makes a good collimation star. Then, place the star diagonal on the scope and check collimation again. If you see a lack of collimation, try loosening the setscrew on the diagonal and tipping it slightly. If this improves the star image, sometimes a thin aluminum shim between the star diagonal body and the tube into which it inserts will do the trick. In this way, the scope can be as well-collimated with and without the star diagonal. Remember to always bring the test star to the center of the visible field before testing collimation.

---

Post Extras:

Quote:

---

I forgot to mention that using a 2" star diagonal on the C6 does lengthen the focal length and narrow the field of view some.
I estimate the adapter and star diagonal have about a 5" light path from the back of the scope to the focal plane at the end of the diagonal (it could be 6"). That length makes the focal length of the scope to 76 to 80", or really f/12.7 to f/13.3
That is one of the negatives of using a 2" star diagonal on the back of the scope.

---

Post Extras:

Quote:

---

Quote:

---

4) These star diagonals may have a misaligned mirror. To test that, if you don't know how to do it off the scope, make sure your SCT is well collimated with a 10mm eyepiece straight through (no diagonal in place).
In the northern hemisphere, Polaris makes a good collimation star. Then, place the star diagonal on the scope and check collimation again. If you see a lack of collimation, try loosening the setscrew on the diagonal and tipping it slightly. If this improves the star image, sometimes a thin aluminum shim between the star diagonal body and the tube into which it inserts will do the trick. In this way, the scope can be as well-collimated with and without the star diagonal. Remember to always bring the test star to the center of the visible field before testing collimation.

---

Don thanks for this tip, but I'm curious, is this a common problem with this particular diagonal, or do you think these are "blems or seconds"? Thanks Bob

---

It's a common problem with ALL Chinese mirror diagonals in 2".
I don't think they're blems. I think they're surplus from what came standard on the larger SCT scopes.

Post Extras:

Quote:

---

Quote:

---

Quote:

---

---

It's a common problem with ALL Chinese mirror diagonals in 2".
I don't think they're blems. I think they're surplus from what came standard on the larger SCT scopes.

---

Thanks Don

Post Extras:

Quote:

---

Yes, this is a 24mm 82AFOV UWA eyepiece. The outer housing screws up and exposes some grease and it does freeze or get stiff in cold temps, so I just keep it up in cold temps when I am observing with it. Views are good in UWA, and the raised outer housing does block stray light.

---

Quote:

---

Price looks very good for the combo sale. Enjoy!

---

Yes indeed!


Mike

Post Extras:

Quote:

---

Wow.. that seems like a crazy good deal. I have the ES68 24mm on backorder. I think I am somewhere around 100,459th in line. IF this Meade is largely the same as the ES82 24mm, then dang. The $159 for the EP itself is a solid price. I think that EP sells for over $200, normally.

Things that make you go 'hmmm...' at 11:30 p.m. Should I cancel the ES68 and jump on this. I have no use for the diagonal, but maybe I could mount it for display on the mantle?!?

I should stop looking at that offer now, before my credit card numbers mysteriously tap themselves onto the keyboard.

---

Post Extras:

Quote:

---

That's a hell of a deal! If I didn't already have that diagonal and a 24mm SWA and a 28mm SWA I'd be all over it...you could buy it and sell them off separately and make $$$

---

Post Extras:

Quote:

---

I always collimate refractors straight-through, without a diagonal in the focuser. Before I observe, I check the collimation with the diagonal. If I the collimation is off, I fiddle with the setscrews or wedge it if necessary to improve the collimation. If I can adjust the diagonal itself, that's even better. I suppose that's how I should proceed with collimating my SCT?

All of this would be easier if I didn't have to wait until I'm out in the dark to collimate. I can collimate refractors and Newts in broad daylight or in my house if I want to. Actually it's EASIER then. Isn't there some way to collimate SCTs accurately without a star test?

Mike

---

Post Extras: