Jump to content

sgl_imaging_challenge_2021_annual.thumb.jpg.3fc34f695a81b16210333189a3162ac7.jpg

200p (skywatcher 8"dob) mod advice.


Recommended Posts

hello ,as title suggests im looking into a few modifications to make the experience of useing the dob easier.

ive already sourced a handle which im going to drill on to the tube,but as im going to take the scope apart to do so i thought it would be a good idea to hold fire untili have the gear to carry out more mods at the same time if you understand me :confused: .

okay, so in a nutshell im after thread types m-numbers ,lengths ect for primary locking and adjustment screws,as well as secondary. trying to source here in uk. bobs knobs would be last resort. so if anyone has done this or has the info be apreciated.

i also read on the forum somewhere about some removing the springs on the primary cell ?

lastly i was thinking about the lazy susan ,but to be honest ive not had alot of trouble with the azimuth,is the lazy susan worth doing ? i have more ...much more issues with the alt , always seems fine in the house ,but as it get colder outside while observing it seems to become stickier .ive tried silicone polish but not with any real improvement. perhaps the turtle wax some suggest may help ?

as you can see im lost without a clue with most mods so advice and help would be much apreciated.

anyway thanks for reading .

Edited by rory
Link to post
Share on other sites

Hi if you are taking the OTA to bits anyway you may as well flock it and the inside of the focuser tube also. You can get flocking material from FLO. Certainly improved contrast on my 200P

Also you can improve the stock focuser by modding the factory supplied one with the lacerta 1:10 microfocuser adapter kit from 365astronomy, am sure u can get elsewhere that's just where I got mine.

Then the usual, setting circles, wixeys, levelling feet etc :)

Skywatcher Skyliner 200p Dobsonian

Celestron Skymaster 15x70 Binoculars

Sent from my iPhone using Tapatalk

Link to post
Share on other sites

thanks catman. i cant stretch to a new focuser at the moment. my priority is having the mount as smooth as possible and thumb screws. the primary more so than secondary as i rarely touch that. ive flocked about 2/3 of the ota when i first had the scope thanks to a kind sgl member passing on thier unused surpless.

ive thought about wixey and setting circles but at the moment im a pure telrad hopper and dont feel the need ,although that may change.

i tghink ive sussed that the secondary nedded are m4 30mm but sourcing them not so easy.

Link to post
Share on other sites

To be honest, given the amount of time and effort put into sourcing the right screws, bobs knobs is actually a pretty good bet. I've tried to find the right sizes unsuccessfully, and even after you find them, they'l likely be hard to source.

The focuser upgrade is just that, not a new focuser. It costs about £60 and is well worth it.

As for bearings, the lazy susan is the best mod i've ever done. And for the alt, i bought some sticky teflon mouse tape and stuck it around the red rings on the side, sorted it right out.

Link to post
Share on other sites

Am with jimmyjamjojoe on the lazy Susan baring mod. I personally haven't done it yet but keep meaning to as a member of another forum I am on has the same scope as me but with the lazy Susan mod and I could not believe what a difference it made! In fact he published a really good guide with links to source the parts and pictures also I think he is on here too. I'll ask him.

Still on my list of to do's-maybe next payday :)

Skywatcher Skyliner 200p Dobsonian

Celestron Skymaster 15x70 Binoculars

Sent from my iPhone using Tapatalk

  • Like 1
Link to post
Share on other sites

To be honest, given the amount of time and effort put into sourcing the right screws, bobs knobs is actually a pretty good bet. I've tried to find the right sizes unsuccessfully, and even after you find them, they'l likely be hard to source.

The focuser upgrade is just that, not a new focuser. It costs about £60 and is well worth it.

As for bearings, the lazy susan is the best mod i've ever done. And for the alt, i bought some sticky teflon mouse tape and stuck it around the red rings on the side, sorted it right out.

oh , i see what you mean now regarding the focuser upgrade. still dont warrant it at the moment ive no real issue with the standard issue. interesting to read about your expeience with the screws though. seems i might have to do a biob knobs then. for both sets primary and secondary come out at £29.00 , i believe thats before postage,so not the cheapest. thanks for the teflon tape tip.

Link to post
Share on other sites

thought id keep my questions on the same thread , weather i get responses ive no idea ? :smiley: carrying on with moding. ive got some exellent p/m's from a few members about lazy susan mods.

so ill be carrying that out soon. im now after a few more ideas as to address balancing ? im thinking of getting a few magnetic strips 6"-8" long ,stick them on to the ota of the dob then i can place a small weight on the strips and move it up/down to suit ? does this sound okay ? or maybe some other options ?

http://www.ebay.co.uk/itm/Premium-Self-Adhesive-Magnetic-Tape-Magnet-Strip-25mm-/270659665497?pt=UK_Crafts_Other_Crafts_EH&hash=item3f0492be59

Edited by rory
Link to post
Share on other sites
  • 5 weeks later...

My replacement knurled head items I am in the process of making are based on the following dimensions:

Secondary mirror adjustment set screws - M4 x 25-30mm

Primary mirror adjustment CSK head set screws - M5 x 12mm

Primary locking set screws - M4 x 10-30mm (needs to clear the Primary screw knurled head, so i'll cut them down to suit)

I have completed the Secondary, so I know they are right (in my case) - YMMV.

Link to post
Share on other sites

My replacement knurled head items I am in the process of making are based on the following dimensions:

Secondary mirror adjustment set screws - M4 x 25-30mm

Primary mirror adjustment CSK head set screws - M5 x 12mm

Primary locking set screws - M4 x 10-30mm (needs to clear the Primary screw knurled head, so i'll cut them down to suit)

I have completed the Secondary, so I know they are right (in my case) - YMMV.

sounds good. where did you get all the different screws from ?
Link to post
Share on other sites

Most hardware stores - BnQ etc. However because I don't always have the time and they don't always have what I want - ebay is an easy choice. BTW the caliper gauge I have is very handy for figuring out what bolts to get. So if you have existing bolts your replacing use them as a sanity check perhaps? Remember also, that you'll need to check it's the right pitch also (grooves per inch etc), e.g. described here: http://www.roton.com/identify_threads.aspx This table here: http://www.zerofast.com/threadm.htm show that M10, for example comes in fine an coarse pitch. The mounting screws on the tube rings I have aren't M sized either, but UNC http://en.wikipedia.org/wiki/Unified_Thread_Standard - a bit annoying after I bought M6 bolts for the job..

Link to post
Share on other sites

Most hardware stores - BnQ etc. However because I don't always have the time and they don't always have what I want - ebay is an easy choice. BTW the caliper gauge I have is very handy for figuring out what bolts to get. So if you have existing bolts your replacing use them as a sanity check perhaps? Remember also, that you'll need to check it's the right pitch also (grooves per inch etc), e.g. described here: http://www.roton.com...fy_threads.aspx This table here: http://www.zerofast.com/threadm.htm show that M10, for example comes in fine an coarse pitch. The mounting screws on the tube rings I have aren't M sized either, but UNC http://en.wikipedia....Thread_Standard - a bit annoying after I bought M6 bolts for the job..

oh no more confusion :shocked:
Link to post
Share on other sites

M4 set screws i bought from Wilkos (the larger stores), the M5's i already had in my garage. It's cost me a whopping £2.40p so far, and I have a couple or so spare. I think they are in bags of 5 or something, so I bought 2 bags.

With the duration the scope's been available, I'm surprised that nobody has bothered to look into the screw sizes previously, tbh. :huh:

Link to post
Share on other sites

M4 set screws i bought from Wilkos (the larger stores), the M5's i already had in my garage. It's cost me a whopping £2.40p so far, and I have a couple or so spare. I think they are in bags of 5 or something, so I bought 2 bags.

With the duration the scope's been available, I'm surprised that nobody has bothered to look into the screw sizes previously, tbh. :huh:

i think some people have to be fair, but there seems to be difficulty matching lengths and sizes with the type of screws people are after (i.e, knurled head ect.) they can be got from bobs knobs,but at a price. i shall try sourcing some at your given sizes.

thanks .

Link to post
Share on other sites

by the way, ive 4 1 inch slide glides left from the lazy susan mod ,as they come in a pack of eight. if anyone reading wants them p.m me with a address and ill pop them over to you.

Link to post
Share on other sites

My replacement knurled head items I am in the process of making are based on the following dimensions:

Secondary mirror adjustment set screws - M4 x 25-30mm

Primary mirror adjustment CSK head set screws - M5 x 12mm

Primary locking set screws - M4 x 10-30mm (needs to clear the Primary screw knurled head, so i'll cut them down to suit)

I have completed the Secondary, so I know they are right (in my case) - YMMV.

The Primary locking set screws are actually M5 x 10-30mm - Not M4.

Sorry for any confusion.

Link to post
Share on other sites
i also read on the forum somewhere about some removing the springs on the primary cell ?

I've been thinking about adding springs to my 200p, it uses o-rings instead, but I've been unsure what size springs to get so this seems as good a place to ask if anybody knows?

The lazy susan mod is the best thing I've done to my dob too.

http://stargazerslou...e/#entry1376145

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By teoria_del_big_bang
      With the recent poor viewing I have decided to strip down my HEQ5 pro mount and upgrade the bearings and add the Rowan belt modification.
      From threads I have looked at on this forum and also looking at the Astrobaby guide I think I need the following bearings, I know many on here have already upgraded the bearings so thought I would just check they are correct before ordering.
       
      I have ordered rubber seals in order to prevent moisture ingress. Now I know these tend to make them run slightly tighter than metal seals but they do not run at speed so though they would be better. Any thoughts?

       
      Steve
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.