Flocking a 6SE

[Leonardo_FL]

Ah, I see what's happening! I probably didn't use the correct settings, because I'm a complete novice in astrophotography. If you gave me some suggestions I would try again. :-)

[Cath]

I'm no expert at astrophotography Leo, don't have the mount for it, wish I did!

I just know that whenever I was taking exposures of probably 20 seconds or more with a bight object just out of the field of view I would get halo rings near the edge of the image in the direction of the bright object, sort of half halo rings anyway (the other half was off image).

[msh1]

i had the same problem with my c6 after talking to the supplier they agreed to exchange it for a new one guess what still got the problem albeit not as bad so i think im going to flock my baffle tube first and see what happens . celestron must know about this there are huge threads on some american forums why don't they flock the tubes themselves stick on a couple of quid extra problem goes away everyone is happy

mark

[Leonardo_FL]

I just know that whenever I was taking exposures of probably 20 seconds or more with a bight object just out of the field of view

Mine were under a second with the bright object inside the field of view. I innocently expected the halo rings to pop up on the LCD display as the star moved outward, like they did in a low power eyepiece! I'm doing more tests tonight. :-)

[Leonardo_FL]

celestron must know about this there are huge threads on some american forums why don't they flock the tubes themselves stick on a couple of quid extra problem goes away everyone is happy

I've started a new thread about this matter in another forum. Although flocking clearly solve the problem, the precise origin of the halo rings is being discussed there.

Could we sign a petition as well?

[msh1]

I've started a new thread about this matter in another forum. Although flocking clearly solve the problem, the precise origin of the halo rings is being discussed there.

Could we sign a petition as well?

can you post a link to the thread please or pm me with it please

[Leonardo_FL]

Mine were under a second with the bright object inside the field of view. I innocently expected the halo rings to pop up on the LCD display as the star moved outward, like they did in a low power eyepiece! I'm doing more tests tonight. :-)

I couldn't capture any halo ring with my EOS 550D attached to the prime focus of the CPC800 last night, no matter the exposure nor the position of the bright object I tried. The halo ring zone of my 8" SCT may be placed far from the chip of an APS-C format SLR. I'm doing more tests with the Meade 6" ACF tonight.

[Leonardo_FL]

can you post a link to the thread please or pm me with it please

P.M. ;-)

[Leonardo_FL]

Hi!

I captured some more before-and-after-flocking pictures, with a SLR attached to the prime focus of the NexStar 6SE. The only flocked part is the interior final stretch of the primary baffle mirror tube. The images were took in an interval of a few minutes, under clear sky. Of course, the exposure and ISO were the same in every photo too.

Before flocking (left) / After flocking (right)

[Cath]

The baffle flocking has certainly improved the contrast by quite a bit! .. It's got to be a must do addition for all SCT users I think judging by our results Leo.

Fix your primary baffles Celestron! .. [pokes them with a stick]

[Leonardo_FL]

Hi!

I unflocked the NexStar 6SE's OTA a few days ago to take some illustrative images of the halo rings, with a SLR camera attached to the prime focus of the OTA - I've increased brightness to bring halos out.

Before flocking (left) / After flocking (right)

In case somebody is asking about the target, they are photos of a prison.

I have the primary baffle tube of my Meade LS6 flocked now and testing. This time I've cut out a piece of adhesive black velour one inch shorter than the one-piece baffle tube to keep the original exit pupil intact - and so the effective aperture of the telescope. However, you can't leave more than 2 millimeters of the final section of the baffle tube unflocked in the NexStar 6SE, in order to avoid any sign of halo rings. By the way, I've been told that Celestron's engineers are examining this matter.

Regards,

Leo

[JamesF]

I wonder if the same effect will apply to Maks as well as SCTs or whether it's just Celestron's design that is the issue?

James

[Leonardo_FL]

Well, I've found this kind of halo rings in every SCT telescope I've tested lately: Celestron NexStar 6SE, Celestron CPC800 50th Anniversary Edition, Meade LS6 (ACF) and Meade 10" LX200-ACF. However, while these halo rings are quite visible even with the standard 25mm eyepiece supplied by Celestron in the 6SE, I needed to use 2" wide-angle low power eyepieces in order to catch the halo rings in the other catadiopric telescopes tested.

[Cath]

Well, looking at your image flocking the primary baffle alone certainly improves things Leo!

I doubt Celestron will do anything about it, I'm sure they already would have by now, but one can hope. Maybe with what we've shown they might think about it, but then again maybe not.

Short of flocking the inside of the main baffle I can't see much else helping. The matt black paint they already use doesn't seem to help much.

btw, the last couple of inches on the inside end of the main baffle on the 6SE tapers out Leo - the inside diameter increases as you go towards the secondary mirror, so the only real way of flocking that bit is to remove the rear assembly (as I did) to get at it.

[Cath]

I wonder if the same effect will apply to Maks as well as SCTs or whether it's just Celestron's design that is the issue?

I don't know what the Maks are like inside but I guess you could try it? .. I expect it's the same for all cassegrain type telescopes, they probably all use a baffle?

[Leonardo_FL]

btw, the last couple of inches on the inside end of the main baffle on the 6SE tapers out Leo - the inside diameter increases as you go towards the secondary mirror, so the only real way of flocking that bit is to remove the rear assembly (as I did) to get at it.

Yes. Luckily, flocking the inside of the cilindrical outer end seems to solve the matter. Anyway, disassembling the rear cell of a Celestron SCT is an easy task.

[Leonardo_FL]

cilindrical

Cylindrical!

[faulksy]

got my self some flocking material today from wilkos, 2 rolls will this be enough ? cost me £30 for the 2 oh no wait that's it £5 a roll but I lost £20 never mind. are you still glad you did it cath ?

[Cath]

oh yes, glad I did it. I've not seen any more halo rings but then I've not had that much chance to use it since, tried it a couple of times on Arcturus and Vega and all seems well. No Moon or Sirius tests yet.

I've also not tried any longer exposure tests - as yet. That was when they really tended to show up.

It's difficult to get clear nights to coincide with my nights off caring for someone, which is why I get so few chances to use my scope these days. But so far the flocking is looking good.

[faulksy]

great news, I will let you know how I get on, bit concerned about collimation though, cheers cath

[Leonardo_FL]

Hi!

I enjoyed my flocked Meade LS6 last night a lot, without any sign of halo rings and an outstanding contrast in the Moon! When the sky was dark and the atmosphere was stable, precious pearls like Swan and Ring nebulas impressed me with stunning clarity. I think this is the beginning of a pleasant relationship!

By the way, I could catch some halo ring in a Sky-Watcher 100mm ED refractor. I'll test it carefully when I can.

Regards,

Leo

[Cath]

I was wondering about what improvements all this SCT/MAK flocking would make to moon viewing, seems the outcasted cassegrains aren't so bad after all once the contrast problem has been fixed.

[faulksy]

mine is all finished, even flocked the inside of the secondary mirror housing, had a slight problem after leaving it over night some fibres had gone on to the corrector so had to remove that clean and remove some more loose fibres, used the 6" ruler approach cath. will do a fresh post on my full strip down of my cpc and ota soon, just need to colimate now

[faulksy]

hi leo, did flocking make that much of a difference then ?

[Leonardo_FL]

Well, the internal glare of the long baffle that goes through the primary mirror in the Meade LS6 was quite lesser than that in the Celestron 6SE, so the contrast improvement by flocking the inside of the final stretch of that tube is lesser too. What I meant is that eliminating the internal glare of the primary baffle tube may turn a good SCT into an excellent all-purpose optics. My comment about nebulas tried to emphasise the good performance a 6" SCT can give you -even better than I expected.