Tubeliner flocking? And reinstalling the secondary?

[ghostdance]

I've been sssslowly thinking about getting round to flocking my 6"/F5 & came across this during my researches:

http://www.fpi-protostar.com/tubeliner.htm

Wondered what flockers views may be? Anyone gone down the liner route? Or would I be better off just using the sheets?

Also, can anyone give me pointers as to how best reinstall the secondary after flocking... I'm guessing there's some measurement involved but can't find a specific guide to this bit of the process.

Thanks all, for any thoughts or tips

[Alkaid]

That liner looks good, as it just rolls up and slips inside the tube.

I would remove the primary mirror first.  Then I would remove the spider (secondary is attached).  Then remove the focuser.  Then flock.  You will need to cut a hole in the flocking material to accommodate the focuser.

My advice regarding the secondary is not to touch the central bolt at all, so that when you re-install the spider the secondary will still be in the same place.  There is a nice trick to get the spider centralised, using a drawing compass you cut out a cardboard circle the same ID as the tube, punch a pencil hole through the middle.  Then insert the card circle into the tube.  Adjust the spider vanes so that the central bolt is under the hole in the card.  Then you know that your spider and secondary is centralised.

Should be easy to re-collimate from here.

[Peter Drew]

+1, says it all. 

[ghostdance]

Hey thanks Alkaid

Sorry for slow reply - thought this thread had passed on!

I am tempted by the tube I must admit. Thanks for the advice re the secondary - it's the one part of the scope that I'm most nervous of messing with, but your advice reassures. The main adjust screw in mine seems stuck fast so I've always left adjusting the secondary alone - collimation looks pretty good thankfully

[spaceboy]

You have to loosen the other 3 grub screws slightly before the main screw loosens.

This thread might be handy if your thinking of doing some improvements http://stargazerslounge.com/topic/202527-just-a-couple-links-members-may-find-handy/

[Joel Shepherd]

Not to ask a dumb question, but how much does a tube liner like this "help"? Does it improve contrast or clarity noticeably? Interesting idea, and I'd be interested to hear from someone first-hand how much of a difference it can make.

Thanks! -- Joel.

[Moonshane]

I doubt you will find any subjective evidence on the impact of this but people pay hundreds for marginal improvements to optics of eyepieces and Scopes. If you can create a marginal improvement for a fiver or so and an hour's work then it seems a bargain to me. I flock my Scopes and will do in future.

[jambouk]

I do wonder if the percieved advantages of flocking outweigh the increased fluff deposition in the primary.

[Moonshane]

I don't think any shed fibres make a difference given it is so far from the point of focus.

[jambouk]

I meant the fibres must have some impact (however small) on the reflective surface area of the primary. And i wonder if the boost in contrast outweighs this. I flocked my newt but as you say i couldn't notice a difference. I'm still waiting for someone to do a good scientific comparision of before and after [under a night sky].

James

[Moonshane]

Not worth even thinking about I reckon.

[Charic]

The thought of using a Dyson puts me off the process of flocking? Any dust will stick like the proverbial **** to a blanket!

I also possess a solid tube OTA so at 4 feet long and a short snood if required, the image is as good as I can achieve without flocking, from my Winter, light polluted observatory?

During the rest of the Year, tree vegetation offers more protection against light pollution, but the Summer skies here are too light for my Dobsonian!

Darker location and / or eye shielding is my preference.

Also note to folk who are concerned with the process of collimation, this must follow flocking, so think ahead, as the telescope requires a total strip down, then when all the screws and bolts are re-attached , any ironmongery will need painting matt black or patched with flocking material.

I have seriously considered the task of flocking, as the results could look very tidy, but the time and effort required over any advantage provided in light reduction in my telescope, would, I assume, would be minor. I have also considered baffling the short snood, but again, would there be any practical improvement. Won't know till I try.

The best option/fix for me is to shield my own eyes from stray light polution, achieved by sitting in my dob-tent?

[spaceboy]

I meant the fibres must have some impact (however small) on the reflective surface area of the primary. And i wonder if the boost in contrast outweighs this. I flocked my newt but as you say i couldn't notice a difference. I'm still waiting for someone to do a good scientific comparision of before and after [under a night sky].

James

May be me but I felt there was a difference

I admit any improvements made to the views are subtle at best but if you continue to do mods then all together your going to get a better overall experience in the end. Mass produced scopes are just that so any tweaks to get the very best from them are well worth it IMHO and flocking for me gives obvious results over any other mods I have done. I say obvious in that if you look down a half flocked scope you can't help but see the improvement in controlling light scatter flock has. That surely has to improve the view in some way http://geoastro.co.uk/ten_newton.htm (not my blog BTW)

[jambouk]

The images of pre- and post-flocked scopes have always been taken in day light with a lamp shining down one end. Not at all reflective, no pun intended, of night time observing.

It's a fun project to do, and a good opportunity to clean the optical components of the scope when you take it all apart, and to get it well collimated afterwards. But don't expect astronomical leaps in contrast.

[Joel Shepherd]

ghostdance - Did you wind up getting the tube liner, and if so notice any difference?

Thanks -- Joel.

[ghostdance]

ghostdance - Did you wind up getting the tube liner, and if so notice any difference?

Thanks -- Joel.

Not yet Joel. Too many non-stargazing distractions lately. Still thinking of doing it though, so I can also springclean as the dust on the mirrors is getting annoying to my sense of aesthetics (lol) and just the other night I found a small spider + web had taken up residence, and not the one supporting the secondary! Must have got in when the scope was cooling, as I keep the scope lidded and cased when not in use

[Joel Shepherd]

Thanks for responding! If you go ahead and do it, I hope you'll post an update. I'm sure there's no silver bullet but I'd be interested in any method for increasing contrast under our light-polluted sky.

Good luck adjusting that spider. ;-)

-- Joel.

[laser_jock99]

Newtonian Rule No.1

Do not remove the secondary- 90% of collimation woes stem from people who did this.......

[Alkaid]

Newtonian Rule No.1Do not remove the secondary- 90% of collimation woes stem from people who did this.......

Yeah, I'm one of 'em! The mistake that I made was to remove the spider assembly and then play about with the central screw which moves the secondary up and down the tube. Do NOT do this. It cost me many hours of collimation frustration with the TAL-1. All is well now though.

Its ok though to remove the assembly without touching this adjustment parameter. Just make sure that the spider is centralised in the tube when re-installing and everything will (should!) be back where it was.

[ghostdance]

Newtonian Rule No.1Do not remove the secondary- 90% of collimation woes stem from people who did this.......

 

Now I feel a whole lot more nervous!

Yeah, I'm one of 'em! The mistake that I made was to remove the spider assembly and then play about with the central screw which moves the secondary up and down the tube. Do NOT do this. It cost me many hours of collimation frustration with the TAL-1. All is well now though.

Its ok though to remove the assembly without touching this adjustment parameter. Just make sure that the spider is centralised in the tube when re-installing and everything will (should!) be back where it was.

Now I feel a little less nervous!

Thanks guys

I'll certainly report back if and when I do the deed, which will probably be around the time my OCD can no longer put up with increasingly dusty/webby mirrors! Gawd knows how the big-mirror owners are not all on tranquilisers

[WakeyTiger]

I flocked my 200P a few years ago, it made such an improvement that I now wonder why manufacturers don't supply them flocked??  Surely that's the best time to do the job??

My view is, it's definitely worth the effort.