Skwatcher 200 OTA modding for maximum performance

[DaveGibbons]

I recently purchased a second hand Skywatcher 200 ota for just over a £100 and have to say I was very surprised when I star tested the optics, they are excellent. It does however have a number of shortcomings with regard to the OTA itself. Firstly the standard rack and pinion focuser has alot of movement and is difficult to hold perfect collimation through it's range. The 1.25" and 2" adapters are a loose fit also adding to collimation errors. Secondly the internal paint on the ota is fairly reflective as is the edge of the secondary facing the focuser, this leads to a reduction in contrast at the eyepiece. Finally the end of the tube only protrudes about 2" from the secondary giving virtually no stray light protection or protecting the secondary from the inevitable onset of dew when viewing for prolonged periods. So here is my attempt to improve on these areas and make a Good scope a great one.

Bare Tube showing not so black paint!

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Bare Tube external

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Fully flocked including diagonal edge

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Fitted with dual rate moonlie crayford

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Finally fitted with an astrozap light/dew shield

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I used felt sheets from hobycraft to flock the tube with. Unfortunately when I called at my local store they did not have any self adhesive backed stuff so I used spray on 3m glue, it is very tricky to do and you can easily get it wrong with overspray etc. By taking extreme care I managed to get away with it but would recommend you use the self adhesive variety!

Also make sure you flock the edge of the secondary as this is highly reflective and must contribute a fair amount to reducing contrast. The Astrozap dewshield is one for a c8 and is perfect for blocking stray light entering the tube along with helping to prevent secondary dew.

So any improvement in optical performance? Well I don't know yet as not had chance to view through scope I will let you know!

cheers

Dave

[Whippy]

Looking good Dave! Gives me a couple of ideas for my C8N .

Tony..

[FLO]

Dave, you have just done precisely what I have been planning to do next Spring!

The Explorer 200p has an excellent mirror-set so with the mods you have just done I am guessing that the results will be superb 8)

BTW, the new Explorer 200 is now supplied with a Crayford focuser, whilst it is no Moonlite it is better than the original R&P.

Looking forward to your first-light report.

[themos]

What flocking material did you use and would you recommend it?

[SteelRat]

Nice work Dave 8)

[AndyH]

That looks flocking marvelous...........

Andy.

[George]

Where does the wife sleep

[BWBlackett]

Where does the wife sleep

:)

[Rob]

Nice job... I love modding stuff, if its not my pc then the astro stuff gets a bash!!. Await the first light of the new 200p GTI now!

[Rob]

The only thing I would have poss done to enhance the whole project is to have resprayed the tube the same orange colour as the moonlite

[philsail1]

Nice improvement job you did there Dave. I like the little touch with flocking the edge of the secondary mirror! I flocked my 200mm Skywatcher Newt but didn't bother with the small secondary. I will now though, as it does have quite a reflective edge to it. I also recently fitted a "Moonlite CR1" Crayford, and I've got to paint the chrome nuts on the inside of the main tube. With reflections, I suppose every little helps!

Regards,

philsail1

[DaveGibbons]

Rob said, "The only thing I would have poss done to enhance the whole project is to have resprayed the tube the same orange colour as the moonlite " - you must be a child of the 60's!

Phil, I have since flocked over the finder mount plate and blackened the nuts.

Upgrader, The wife sleeps in a seperate room with the 10" intelliscope- it's a size thing!! :shock:

Themos, The material is hobycraft black felt sheets stuck with 3m spray on adhesive. they cost 49p each and it took ten of them for the job. As I said it would be far easier using self adhesive variety of the product which I believe they do sell but I just could not wait.

cheers

Dave

[Rob]

Rob said, "The only thing I would have poss done to enhance the whole project is to have resprayed the tube the same orange colour as the moonlite " - you must be a child of the 60's!

Phil, I have since flocked over the finder mount plate and blackened the nuts.

Upgrader, The wife sleeps in a seperate room with the 10" intelliscope- it's a size thing!! :shock:

Themos, The material is hobycraft black felt sheets stuck with 3m spray on adhesive. they cost 49p each and it took ten of them for the job. As I said it would be far easier using self adhesive variety of the product which I believe they do sell but I just could not wait.

cheers

Dave

I am indeed Mate!!

[sublime_mick]

can you please PM those pics? they seem to be gone have the same scope and want to see what your mods look like.

[DaveGibbons]

Sorry Mick, I no longer have copies of them.

cheers

Dave

[fwm891]

Pictures please Dave