38 replies to this topic

[swix]

I purchased a C6 last month to use with the AVX & CG4 mounts.
The C6 had baffle tube issues with a halo around bright stars and
planets. I also had the diamond ring effect when these bright
objects were just out of the FOV. Very annoying. I contacted
Celestron and they said they would correct these problems and
would take about 30 working days. I decided to try my own fix.
I use the scope with a Baader 2" click-lock and a 2" diagonal.
This adds about 135-140mm to the back of the scope. It should
give me a focal length of 1700mm. With this combination, I am
using the C6 at close to the optimum back focus of 5 inches.
I took flocking that I got from Scopestuff and proceeded to figure
out how long to make the flocking tube. The tube in the C6 is
8 inches long. I ended up with a flocking tube 3 1/4 inches long
so I would not have or cause vignetting. The diamond ring effect
is gone and the halo has been reduced by about 80% with this
flocking inserted into the tube and did not have to wait 30 working
days for the correction. I was very disappointed when I first got
the scope but now it is very usable.

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[swix]

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[swix]

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[stevew]

Congratulations on fixing your telescope.
It's too bad Celestron has not addressed this issue with the very popular C6.
I see no such problems with my C5.

Steve

[Bill Barlow]

Nice job..big improvement. What type of flocking paper did you use? Did you just insert it into the baffle tube from the rear cell opening? Did it have an adheasive/sticky backing? I had a C6 a while back and seem to remember these flaring/halo issues when viewing brighter targets.

Bill

[swix]

I used the flocking that Scopestuff sells. It is adhesive backed. I cut a piece to the correct size and then glued it to a plastic zip lock bag. This allows it to slide into the baffle from the rear. I cut small pieces of double backed masking tape to secure it to the scope tube. I had no intention of taking the scope apart. I am not that talented.

[Terrel]

I too recently purchased a C6 from High Point Scientific. I have not had the problems you describe. I just looked at the inside of the baffle tube on mine and it has shallow circular ridges approximately 15 per inch the entire length of the tube and has a flat black finish. Yours looked almost polished on the inside. Happy it worked out.

[swix]

I too got mine from High Point. Not their fault , just a quality control issue in China...

[areyoukiddingme]

I've been messing with this on mine too. First I tried the painted sand paper, but fit was not easy and it vignetted a bit (I was way over ambitious and did close to the full length of the tube).

Then I tried some protostar plastic-backed flocking (two birds--I will do the inside of the tube with this stuff, but I'm guessing that the improvements here will be mild).

But tHe plastic-backed stuff is too thick for the baffle tube. . . and now having pulled out the sand paper and protostar stuff, my baffle is as shiny as ever!

Anyway, I think I will try the scope stuff, stuff next.

[coopman]

So you did not remove the backing from the flocking paper, which would have exposed the adhesive?

[coopman]

Did you put the flocking on the front part of the baffle tube or on the rear of the baffle tube?

[areyoukiddingme]

Protostar has plastic backed paper--it is not removable/no adhesive side.

I put the flocking "paper" in about 90% of the baffle. That's where I went wrong. It should work, but it difficult to get right. I think going for more like 70% would be easier and will be pretty good.

[swix]

I cut a piece of the Scopestuff flocking to the size I needed. The
flocking tube has an ID of about 1 inch. I wanted the flocking to
be 3-1/4" in length. I then tested the fit with the backing paper
on the flocking. OK, next was to remove the backing paper exposing
the adhesive. This was then attached to a plastic zip lock bag.
I trimmed the excess to the size of the flocking. I cut small pieces
of double sided masking tape an attached them to the plastic backing
now on my flocking. Roll the flocking and place it in the baffle tube
from the rear. Use a pencil or finger to gently attach the flocking
to the inside of the baffle tube. If you try to insert the flocking
with the adhesive backing it becomes too difficult for a proper fit.
The small pieces of masking tape will hold the flocking in place.

[coopman]

My C6 baffle tube has just been flocked. Thanks for your help, Peter.

[areyoukiddingme]

Ditto, THANKS!

My overly ambitious attempt was nearly 7" of the protostar plastic-backed stuff. I cut it down to 5" and tried again (I rolled it around a drum stick and jammed it up the bum of my c6). First try didn't work (again, a little overlap at the top end that I couldn't get to snap into place).

Then a very slight strip off the end, a second shot and home! Zero vignetting and clearly working!

Next the inside of the tube . . . . . . . .

Scott

[Gil V]

What? A Celestron scope that isn't perfect?

Go figure...

[orion61]

I too got mine from High Point. Not their fault , just a quality control issue in China...

SWIX...I'm trying to figure your quote. Celestron IS a Chinese company now.. so it is Celestron's fault.

[orion61]

I too got mine from High Point. Not their fault , just a quality control issue in China...

SWIX...I'm trying to figure your quote. Celestron IS a Chinese company now.. so it is Celestron's fault.

[orion61]

What? A Celestron scope that isn't perfect?

Go figure...

Good one Gill, nice shot across the bow... Snicker, snicker

[swix]

Not High Point's fault....

"You give them eye's and they cannot see"

[coopman]

It's an easy fix regardless of who's fault it might be.

[XRinger]

Did you put the flocking on the front part of the baffle tube or on the rear of the baffle tube?

 

Clay, I see you have flocked your scope.. Did you ever find out where to put the flocking? (I didn't see a reply to your question).

 

I have done a bunch of reading about the problem and the evidence seemed to point to the upper end of the baffle tube (where the light enters it) as the area that needs to be flocked.

Logic seems to say the entrance will be the most sensitive to any off-axis light coming into the baffle...

It seems like off-axis light, bouncing off that primary area can shoot directly down to the camera's sensor. Passing cleanly over the rest of the baffle.

 

I've peeked inside my new (High Point) C6, and it appears to have a very thin tube inside the very top (entrance) of the baffle tube.

It's not very long, compared to the overall tube. It's not as shiny as the lower part of the tube.

All my bright star testing (using the AVS DSO-1 set near max sensitivity) shows the factory flocking is working great. No rings.

However, I have not had very good weather here, so these results are somewhat prelim. Maybe the rings won't show unless the 'Seeing' is really great.

 

Cheers,

Rich

[aa6ww]

Because of this topic, last night I deceided to set up my C6 and see how bad that "Diamond Ring" effect was since Jupiter is out now.

Sure enough, it was present. I haven't had this C6 long enough to use it on Jupiter, since its just coming around now in the late evening, but the diamond ring effect was there and somewhat annoying.

I read somewhere in another thread that some people are slipping some flocking material in the back of their light baffle, as far in as they can do this. I tried this, cutting 3/8" strips of flocking material and inserting them into the tube and it didn't help at all.

Shinning a light into the OTA from the front, I saw light refecting off the front edge of the baffle, so I thought this has got to be where this issue is coming from. So this morning, I removed the corrector and removed the shorter strips of flocking from inside the tube, and replaced them with full length strips, and even folded them over the front of the baffle completely covering the rim of the front of the baffle. I even added an extra 1.5" of flocking to the outside of the light baffle, so there would be no internal reflections coming of the inside or outside of the baffle.

Since I had the scope opened, I also added flocking material around the inside of the secondary baffle. Though this may or may not help, I noticed theres a machined ridge on that baffle that could be catching some reflections also. I unscrewed the primary mirror out of the corrector, (its notched so it only goes on one way and its very precise) and added the black flocking material down the entire length of the inside of the baffle, the length was 1.25" exactly. This completely covered that exposed beveled ridge.

Finally, since the corrector was off, I flocked the inside of the C6's walls completely. I did this because the scope was already opened, because I had plenty of black flocking material, and because every screw protruding into the inside of the scope was a shinny chrome screw. This turned out beautifully, since the flocking sheets I have are 9" x 12", and the inside of the C6 is font to back is exactly 9" long. So I cut each sheet 6" wide and added 3 equal sheets inside the OTA, and added one additional strip 9" long by 3" wide. This covered all the exposed shinny chrome screws also.

Now the inside of the C6 looks like an Mk67 I use to have years ago. If the diamond ring effect is still there, all I have left to cover would be the secondary rim which I didnt cover and the outside of the secondary light baffle.

I would have liked to do this in stages, but I just basically covered everything, since I had the time, and wanted to get this working properly.

I may need to realign the secondary and that's no problem. Once I'm done, I'll report back on if it worked.

By the way, removing the corrector was easy, and everything went back in place perfectly. It also made adding strips of flocking material down the full length of the light baffle very easy, since both ends could be pulled on and positioned so every strip is right up against the other strips.

...Ralph

[Starman81]

Because of this topic, last night I deceided to set up my C6 and see how bad that "Diamond Ring" effect was since Jupiter is out now.

Sure enough, it was present. I haven't had this C6 long enough to use it on Jupiter, since its just coming around now in the late evening, but the diamond ring effect was there and somewhat annoying.

I read somewhere in another thread that some people are slipping some flocking material in the back of their light baffle, as far in as they can do this. I tried this, cutting 3/8" strips of flocking material and inserting them into the tube and it didn't help at all.

Shinning a light into the OTA from the front, I saw light refecting off the front edge of the baffle, so I thought this has got to be where this issue is coming from. So this morning, I removed the corrector and removed the shorter strips of flocking from inside the tube, and replaced them with full length strips, and even folded them over the front of the baffle completely covering the rim of the front of the baffle. I even added an extra 1.5" of flocking to the outside of the light baffle, so there would be no internal reflections coming of the inside or outside of the baffle.

Since I had the scope opened, I also added flocking material around the inside of the secondary baffle. Though this may or may not help, I noticed theres a machined ridge on that baffle that could be catching some reflections also. I unscrewed the primary mirror out of the corrector, (its notched so it only goes on one way and its very precise) and added the black flocking material down the entire length of the inside of the baffle, the length was 1.25" exactly. This completely covered that exposed beveled ridge.

Finally, since the corrector was off, I flocked the inside of the C6's walls completely. I did this because the scope was already opened, because I had plenty of black flocking material, and because every screw protruding into the inside of the scope was a shinny chrome screw. This turned out beautifully, since the flocking sheets I have are 9" x 12", and the inside of the C6 is font to back is exactly 9" long. So I cut each sheet 6" wide and added 3 equal sheets inside the OTA, and added one additional strip 9" long by 3" wide. This covered all the exposed shinny chrome screws also.

Now the inside of the C6 looks like an Mk67 I use to have years ago. If the diamond ring effect is still there, all I have left to cover would be the secondary rim which I didnt cover and the outside of the secondary light baffle.

I would have liked to do this in stages, but I just basically covered everything, since I had the time, and wanted to get this working properly.

I may need to realign the secondary and that's no problem. Once I'm done, I'll report back on if it worked.

By the way, removing the corrector was easy, and everything went back in place perfectly. It also made adding strips of flocking material down the full length of the light baffle very easy, since both ends could be pulled on and positioned so every strip is right up against the other strips.

...Ralph

 

Sounds like a fun project, did you take any pictures?

 

Flocking material is relatively inexpensive and I am not averse to taking apart my C6--are there any pitfalls one should be aware of? Any "don't ever do this" or "be careful with that" type of cautions? 

[doug mc]

Light can also reflect off the short areas just in front of your eyepiece holder. If using a 1.25 diagonal, flock those points as well. Just point your scope outside during the day, remove your eyepiece and flock those areas that light up in the optical path. You will see as I did that it is not only the inner baffle wall but sections of some diagonals as well. It all helps.