Dob Mod Service..?

[johnkirkpatrick]

Is there anywhere in the UK that provide a mod service for people like myself (Useless)? Somewhere that does flocking collimation mirror cleaning, that sort of thing..

[Chris H]

None that I know of but with regard to the things you listed I've read a lot about flocking and the benefits seem to be minimal, mirror cleaning is something you don't need to worry about just yet, I reckon if a mirror is looked after it would probably last years between cleaning and finally collimation is something you need to do regularly so best to have a fiddle and it will click into place eventually.

[callisto]

Sorry Kris77, I have to say since I have flocked my Dob, the contrast on Moon, Planets and some fuzzies have have been very noticeable, IMHO well worth the mod

[Chris H]

Sorry Kris77, I have to say since I have flocked my Dob, the contrast on Moon, Planets and some fuzzies have have been very noticeable, IMOA well worth the mod

Only going of what I've read on both this forum and cloudy nights, don't have first hand experience.

[johnkirkpatrick]

Hi Chris, I have read both good things about flocking and some also say it makes no difference, I would give it a go. My scope seems collimated well just now so it aint a prob and I do need to try it myself lol. I was thinking of changing the rack n pinion to a dual speed, but dont fancy taking the spider vain's out. I find the standard rack n pinion just to harsh on the focusing. either too much or too little. and fancy the duel speed crayford for £99 at flo. and also fancy a fan for the mirror but no clue how to do that one

[Chris H]

I fitted a Moonlite CR2 dual speed focuser and I did not have to remove the spider to fit it, I was just very careful.

Is there a club or society near you? That would be the best option.

[johnkirkpatrick]

there is and been to my first meeting last month, missed the second due to the cold or "man flu" as my wife calls it lol. I will ask them if they know how to flock. i could prob do that my self but it the fact of not having the balls to take it apart lol. I did wonder about fitting the focuser without removing the vains as there's plenty of room to get in and about the screws. as long as i dont have to drill new holes

[brantuk]

Again not from experience but just by deduction - if the purpose of flocking is to absorb stray light bouncing round the tube - then I imagine it might make a significant difference if you are observing from a light polluted area where there's a lot of stray light.

If you're in a real dark observing place however, I'd think the difference experienced would seem less obvious.

[Talitha]

John, drilling holes really isn't too bad. Just make sure you measure properly, place the tube sideways, and put a towel on the inside of the UTA to catch all of the metal shavings. I added two outside handles to the 16" LightBridge and it went quite well.

As far as flocking, you might try doing a temporary job using felt and double-stick tape. Remove it halfway through the session to see if there's enough of a difference to do it permanently.

When it comes time to clean my mirror, i'm leaving it in the base... if the procedure is good enough for an Obsession, it ought to be good enough for my Seymour.

[Peter Drew]

A maximun benefit-minimum effort approach is to flock an area opposite the focuser, large enough to cover the apparent field of the lowest power eyepiece. A front fitting light shield if the secondary is near the open end of the tube also helps keep out off axis reflections.

[johnkirkpatrick]

I heard about using felt, but some say that the felt fibres can flake off and settle on the mirror, also a sharpy pen can be used to colour edges of the secondary. As Peter say's, I might flock the area around the secondary as i could do it in strips

[JamesC]

I used black acrylic paint to blacken the lip of my secondary. Worked nicely. Of course I removed the secondary to do the painting.

[johnkirkpatrick]

I have blacken my mirror now, hope its still ok. just coloured round the edges and the back with a sharpie. did it without removing it. scary stuff lol. not sure if i will notice any difference? is there anything else I can do?

[spaceboy]

I was very cynical about the cost to improvement of flocking but as you will see from these threads I pretty much needed a solution to an error on my part. In doing so I have experienced a significant improvement in contrast and found it's made my viewing more pleasurable.

http://stargazerslounge.com/beginners-help-advice/114997-dont-try-home-update-1-a.html

http://stargazerslounge.com/beginners-help-advice/116002-dont-try-home-update-2-a.html

http://stargazerslounge.com/beginners-help-advice/117340-dont-try-home-final-update.html

The only debate would be if it is truly necessary to flock the length of the tube as with my 200p the last 2" or so I ran out of flock and it has still made a noticeable contrast boost.

[acey]

The only debate would be if it is truly necessary to flock the length of the tube as with my 200p the last 2" or so I ran out of flock and it has still made a noticeable contrast boost.

It's not necessary. ProtoStar suggest it (easy to see why!), but this S&T article convincingly argues otherwise:

http://www.urania.be/forum/download.php?f=1&file=baffling.pdf

I baffled my Flextube 12" using steps suggested in the article and it has made a big difference. My solid-tube Orion 8" never needed flocking. The difference that mattered most between the two scopes was, I think, the focusser: low-profile (and poorly baffled) 2" on the SkyWatcher, high-profile 1.25" on the Orion, the latter letting through a lot less stray light to the eyepiece. For the 12" I needed one sheet of ProtoStar and there was loads left over. Other investment was a Sharpie pen for the secondary. Only parts I needed to remove were the focusser drawtube and a single screw on the scope tube.

http://stargazerslounge.com/equipment-discussion/99482-improving-flextube-contrast.html

[spaceboy]

low-profile (and poorly baffled) 2" on the SkyWatcher, high-profile 1.25" on the Orion, the latter letting through a lot less stray light to the eyepiece.

I have heard this about the low profile focused. I am looking for a duel speed focuser but felt the low profile offered more in the way of having compression rings to protect the ep's from dimples. I don't plan on photography but wanted the option of a little fine tuning.

Has the pros and cons ever been gone over regards focuser's in the budget range as I don't want to make contrast problems for myself.

[acey]

Low profile is fine as long as it's well baffled. In the case of the SkyWatcher I found that lining the drawtube with Protostar and putting a cardboard ring baffle on the end was enough. Those with more stringent requirements would probably want a further annular baffle inside the focuser tube, or a fixed baffle beyond the focuser. The size of baffle can be done by guesswork or using a program such as Newt.

Dale Keller's Newt Software page

I suspect the focuser to have been the main culprit for the light-scattering problems I had with the SkyWatcher as compared to the Orion. [removed word] Suiter recommends focuser baffling as tip number ten here:

Top Ten Ways of Improving Newtonian Telescope Optics

I'm happy enough with the stock Crayford on my SkyWatcher after doing the simple mod. Don't know what more expensive focusers are like but I notice that the Orion UK Crayford is described as having a "light baffled draw tube".

http://www.orionoptics.co.uk/ACCESSORIES/focusmountspage.html

The following page on the William Optics Crayford includes comments on focuser replacement and baffling.

http://www.tomhole.com/William%20Optics%20Crayford%20Focuser.htm

[spaceboy]

How do the revelation duel speed focuser fair against Sky watcher? Or is it just better getting the standard focuser with duel speed and flock inside?

I ask as I have a revelation on order and if I need to mess around too much I'd rather get the standard focuser.