Reviving an unknown newtonian

[Devin]

I recently was given a celestron newtonian scope, it had sat on the tripod for an unknown ammount of time at an auction hall, I believe for years.

I only have access to the internet over my phone and im not completely shure how to upload pictures, but I will get some up one way or another doon. I have inspected the telescope itself and I believe that it is collimated however the main mirror brackets are very slightly visable. I also have 20mm plossel and 5mm x-cel eyepieces, and what I believe is an equatorial mount.

The scope reads

celestron

150mm Newtonian

telescope 1000mm f7

Viewing has been well frankly illuminating and awe-inspiring, it has given me somthing that I very much needed to focus on. Just knowing my place in the universe has brought tremendious help? relief? Its just been exactly,what I needed now in this time.

While viewing I have been comparing the eyepieces and working on increasing my focous and following/ centering.

Earlier last week I decided to clean the eyepieces as I could see buildup on both sides of them. Once this was done I noticed a significant increase in backround clarity espically. I have been advised not to attempt to dissamble the ? Spider assembly ive heard it called, or to clean the main mirror directly. At this time I compleatly agree because I realize I dont understand what to actualy do or espically not to do. This would require re- collimation also?

I would like to try and atleast use some air to clean the secondary assembly and the main mirror.

The tripod seems to be compleatly functional, at first I thought the Ra guage was broken, but it was shown that I needed to familiarize myself with it. I do feel an amount of resistance in the hand controles I believe the lubrication may have settled or become tacky, would it be necessary to dissamble it?

Any information about celestron newts and maintaince would be awsome

clear skys!

[Stargazer_00]

Hi there,

Sounds like a good scope, glad you're enjoying it.  Collimation is a necessity so I would advise you to pick up a Chesire collimation accessory.  Reltaviely inexpensive and a pretty easy procedure.  At F7 the scope will be tolerant to slightly poor collimation and will hold it's collimation well one configured.

In terms of cleaning.  You can remove the secondary spider and mirror if you are careful but it will absolutely demand collimation again once reinserted.  You need to ensure the mirror is centered once relocated so you need a small ruler. Ensure all edge to centre measurements are the same.   Then you need to ensure the secondary mirror is correctled rotated to point at the draw tube of the focuser, then you can collimate it's tilt as required using the 3 tilt screws.

The primary mirror can be removed from the bottom the tube usually.  There are screws on the outside of the tube you can undo and remove the cell and mirror together.  Once out you can clean it with an air duster.  Most of us use a bulb puffer.  I got mine at Maplins for £5 I think.  Maplins sell them as watch repair air puffers or something like that.  There are various designs but essentially its a one puff rubber chamber you squeeze and air is forced out a tiny nozzle.  Great for removing loose grit and dust without touching the surface.

Anything more demanding requires a contact clean, where you have to make contact with the mirror to clean it.  This should really only be done if you believe the debris is causing significant loss of quality, and it really takes an awfully large amount of debris to have a real effect at the eyepiece.

I would also state that cleaning eyepieces should be done with extreme caution, I hope you didn't just wipe them with a tissue or the edge of your shirt or something.  I usually clean mine with IPA and cotton buds, very gently starting from the centre going in circlular motion and out towards the edge like a spiral.  Throw the bud away after each use, dont reuse it otherwise you run the risk of sratching the eyepiece with any grit you may have picked up.  Damage to the eyeglass will have a much greater effect on the quality of the image than light debris on the mirrors. The eyepiece makes up 50% or more of the system.

No matter what optical surface you clean, ALWAYS blow the loose dust/grit off of it first with a puffer.  Do not blow on it as you will just end up depositing a lot of saliva on it and making things worse.  Dont use breath as a way to put moisture on the surface either as this is just the same. 

Hope that helps. Not trying to put the frightners on, just making sure that caution is observed

[Cornelius Varley]

FYI the telescope is probably a Celestron C150HD. There should be a manual available for it on Celestron's site.

[wookie1965]

If its the same model here is the manual

ftp://downloads.celestron.com/pub/manuals/telescopes/c_series/31056_c15hd/manual/31056_c150hd.pdf

[Devin]

Stargazer thank you for taking your time to write so much. For starters I Did Not wipe the eye piece down with my shirt c: I used a cotten tipped swab and alcohol in a similar manner as you described. As a chimney sweep and a masonry tender my shirt would probably do more damage then most. Weve just done a rebuild so I havent gotten any time to work on my scope this week, im just now getting a chance to post here, but I have been thinking.

I completly appriciate what you are saying about contact clean and to remove any particles with air firat. Im not going to remove the primary mirror at all I dont tjink that would be benifical in any way.

My plan right now is to remove the spider assembly and clean the secondary abd the attached lense. I may use a cotten swab and some solution if necessary but im hoping some air will be enough.

As far as the primary mirror is concerned if nothing but photons ever contacts it I will be a happy man

however I was wondering if a spray of dis water would leave any residue or if it might collect particles that the air could cause to scrach the surface?

I am still new to collimation, and it may be a few weeks untill I can get a collimation tool, there are no convient astro supply stores near, I was wondering if making a collimation cap would sufice untill then? I do want to re-collimate it again for practice as much as anything.

If it clears up I would like to view probably before I dissamble and clean and re-collimate. In looking into the eyepiece I can see all of the primary mounting brackets, but only barely. Does this mean that the secondary needs to be pulled back or do I adjust the primary? The reflection of the secondary and the focuser seem centered and not ofset I.e for a faster scope.

To cornealus and wookie thanks Im reasonably shure you guys are on the money thanks

Might be friday before im back thanks for all the help again

Clear Skys!