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Old 02-07-2012, 01:46 PM
h_ngm_n (Will)
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Scored an old Mak, needs some maintenance

Hi there celestial gazers,

My first post - I scored a 6" (152mm) by 1900mm Maksutov Cassegrain . It is from a relative that bought it a trade fair years ago and never used it that much. It is Saxon branded. It comes with a non-automatic mount and a couple of eye-pieces. It's in fairly good condition except the dust cap was left off of the diagonal so the diagonal mirror is very dusty and there is some dust in the main body but not too badly in there.

Could someone please give me some quick advice about the following?

1) Is it possible for me to clean? It is plausible for me to take out mirrors and clean them in alcohol or something (no air?) and reassemble.

2) What would I expect to see with this?

3) I've read on the forums that this is a rebranded scope of reasonable quality... is it worth spending some money on?

Any thoughts greatly appreciated!
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Old 02-07-2012, 02:46 PM
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With regards to cleaning, unless you can clearly see significant marks on the mirror, I would not clean it. A small amount of dust will have no appreciable impact on optical performance. If in doubt, you could seek an opinion at an astro shop - take it in for them to look at.

You can easily clean the front (outside) meniscus corrector. First try a (lint-free) microfibre lens cloth by simply breathing on the plate and wiping - do small sections at a time. Only use cleaning solutions if that doesn't work (and there are plenty of threads and web pages on cleaning optics).

The Saxons are underrated regarding quality, IMHO. The MakCass design is robust and pretty decent - you can look up the fundamentals of telescope designs and various reviews. I think it makes a good planetary scope and at 6" you should be able to see the planets quite well plus doubles, clusters, etc. Deep Sky Objects (DSOs), like nebulae, galaxies, and so on, may be a bit of a challenge unless at a really dark site, but you can still try. That design is also fairly gentle on eyepieces. The longer focal length will mean that photography is a bit more demanding, but still doable. I think it's a pretty good "take anywhere" scope.

Edit: Oh, yeah, there's no user collimation with those scopes - there should be three collimation screws under rubber covers at the back, but you shouldn't need to touch them.

Don't spend too much on your first scope! Learn what you want to do with it first and how commited you are to astronomy. At least, that's my 2c worth.

Last edited by Astro_Bot; 02-07-2012 at 02:57 PM.
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Old 02-07-2012, 03:14 PM
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Yes good advice , dont touch it if its only a little dust , as they say a little dust wont hurt the views , but !!! scratches definatly will .
On the diagonal Be very careful as the alliminum coating is soft and scratches easily , I use a can of compressed air I got at 'Camera House' for $20 and it blast's dust and grime offf very well , just dont get to close as you blast away . .
As AstroBot said just learn how to use it and enjoy .
A couple more things , these scopes take a long ( 1 Hour+) time to settle down when you first take them from a warm house to the outside cold
, so the images wont be the best until the glass settles down , its because of the closed tube design , thats the way Maks are but give great views when acclimatised . Lots of Mak owners leave them covered in the shed . .
And hows about a few photos of the scope , mount and dust ? .
That always helps '
Brian.
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Old 02-07-2012, 03:35 PM
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Oh yea , one more thing ,,,, Mak's by their design have long focal lengths and I think your 150mm Saxon has a focal length of 1800mm .
So a 10mm eyepiece will give you 180x (1800 divided by 10 = 180x ) and thats high magnification , even a 20mm eyepice is 90x (1800 divided by 20=90) and thats still way to high to start with . .
You need at least a 40mm eyepiece to give you 45x to start using easily as the higher the mag, the smaller the field of view and at 180x or even 90x thats a small chunk of the sky and its easy to get lost , frustrated and give up ...
So what eyepieces do you have ?
We will start there , ok .
Brian.
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Old 02-07-2012, 05:03 PM
h_ngm_n (Will)
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Thanks for the help so far! It came with 20mm and 6.5mm eyepieces. So perhaps I may need to buy something a bit longer than 20mm. Any recommendations on brand etc?

I'm thinking the diagonal will prob need a clean as for the main body I'll wait until I try it out before attempting and even then may take it into a store. I've had a read on the threads here and a lot of good info in there too! Great site. I read around that the diagonal mirrors on these are a weak point of the unit. What about buying a new one?

How does the mount look to you guys? Can you buy kits to automate these or do you have to start from scratch. Thanks again...
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Old 02-07-2012, 05:38 PM
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Yep you definatly need a longer eyepiece , as the 6.5 is about 270x ,, thats way to high .
Looking at the scope , yes it aint to bad , I would just give the outside a quick dusting , the tube not the glass .
Google AndrewsCommunations , they have 2 inch eyepieces for $49 - $79 I think and the 26 mm and 38mm would be perfect , the diagonal looks like a 2 inch model ? measure the main hole where the eyepiece goes - without the adaptor .
Those diagonals can come apart by unscrewing the back ( 4 screws ) and carefully removing the mirror , dont touch it with your fingers!!! as the oil in onr skin damages the coatings . Do this on the table with a towel laying on it . . Just in case you drop it .
Then put it on a tea towel in the sink and blast it with high pressure warm water from the tap for 5 miniutes . This will disloge the worst of the dust without hurting it .
While you are doung that get some real " Sunlight Soap" diswashing detergent , nothing else as this is the best ( 10 drops in 5 letres of warm water in a plastic container ) , use nothing else ! .
After the blasting place the mirror , place it in the warm water with the mirror up , close the plastic containers lid and put it aside for a few days to soak . .
We will get back to the mirror then .
On the mount , is there another counter weight ? that single one looks way to light to balance the weight of the tube , you may need another about a 5kg one from Bintel , gooogle that as well , not to dear .
Equitorial mounts wont work unless they are balanced properly , another way to loose intrest real fast , trying to use one unbalenced .
Whew .
Stick with it mate we will get there .
Brian.
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Old 02-07-2012, 05:44 PM
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That is a fair bit of dust on the diagonal, although I usually find it's worse in a close-up photo than in real life, so try it an see. The moon is a good place to start and near full right now.

In the 2nd photo there are a couple of vertical marks. Are they on the front corrector or the mirror?

A lower power eyepiece (EP) would be good (40 - 42mm ideally, as Brian said). Try to keep above 35x magnification as below that you may get intrusion of the secondary into the image (it'll depend a bit on the size of the secondary). Magnification is just the ratio of focal lengths, so mag = 1900 mm divided by X mm, where X is the EP focal length.

There are as many opinions on EPs as there are astronomers! The focal ratio of your scope is fairly gentle on eyepieces, so you will benefit less from exotic/expensive designs. Having said that, at lower power, you may be more interested in a wider field than a regular plossl will give ... or maybe not. The best bet is to join a local club (usually very cheap) and try some EPs in your scope at one of their viewing nights - that'll give you an idea of how much importance you place on field-of-view (FoV).

For automation, you can buy a motorised/go-to mount (sometimes here in the classifieds or other trade sites). But, give it a go on the existing mount. A go-to mount will set you back quite a bit, so make sure you're happy with the optical tube asembly (OTA, a.k.a. telescope) first before spending more money. Besides, learning to "drive a manual" has its own satisfaction ... and it'll make you learn the sky, which is valuable ... before you sell your soul and get a go-to!

Edit: Posted before seeing Brian's latest reply (I type s-l-o-w-l-y).
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Old 02-07-2012, 06:11 PM
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I think we will get this budding astronomer on the right track , AstroBot ?
That is good advise ,get out tonight and look at the full moon using the 20mm at 95x , woaw that still very high power , you wont fit it in a field of view , ( forget the 6.5 ) , it may be a little hard to find , but hey its BIG and Bright ,
One more thing , do you have an idea which way is south ?. it wont matter to much about that tonight , but using an EQ mount you need to know roughly where it is .
Give it a go and please let us no how you get on .
Brian.
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Old 02-07-2012, 06:20 PM
h_ngm_n (Will)
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Hey, yes there is another counterweight and I just put it on the stem now. It feels about 5ish kgs. You can see it in the background of the first photo. Ok, I will look into some other eyepieces. Will you be able to see the rings around Saturn with this unit? I have been reading up on it and opinions seem very polarised on Maks. Can you recommend a society in Brisbane, on the northside preferably? Trust me the diagonal is FILTHY! I will go set it up in the back yard now and let you know how I get on. Thanks
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Old 02-07-2012, 06:34 PM
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We'll get him there, Brian.

Here are some links on balancing an equatorial mount:

http://www.iceinspace.com.au/63-498-0-0-1-0.html

http://starizona.com/acb/basics/usin...ncing_gem.aspx

Now, if you'll exuse me, I'm going to do some viewing myself.
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Old 02-07-2012, 06:39 PM
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Will , I will send you a PM regarding an eyepiece , and on the south if you point the tube torwards south with the telescope in the position its in , in relation to the first photo and then move the mount and tube to the east , where the moon will rise very soon leaving the Tripod where it is that will be set roughly south . .
Dont worry to much about this if its to much info ,,
Brian
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Old 02-07-2012, 07:26 PM
h_ngm_n (Will)
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Ok so, success! I now know what you mean about balancing though... even when I turned the focus knob (?) the scope would drift a bit. I'll check those links out and learn how to set it up, thanks for those. With the 20mm it was fantastic I could see all the moon and it was most dramatic looking at the edge. The image was very clear with this piece. I didn't really wait for any temperature adjustment just went straight into it. My eyes aren't what they were 3-4 years ago though. It took me a while just to get used to looking in the piece. With the 6.5mm I could get it to focus (just) on craters on the edge of the moon. It felt like they were popping out at me and I could see over the edge and into them. Great stuff But it was a lot blurrier than the 20mm. I gather dust would affect this piece a lot more more but also my lack of experience. Still I can not believe how clear it was with the amount of dust that is on that diagonal. Thanks for the help. I will keep posting as I go
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Old 02-07-2012, 07:52 PM
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Hi Will,
Welcome to IIS and I hope you get your scope up and running soon.
I'm from Brisbane and if you click on the Our Community link on the LHS of the page then you'll find a link to Clubs and Societies.
From there you'll find the Qld/Brisbane ones except for some strange reason the Brisbane Astronomical Society http://www.bas.asn.au/
All the clubs have public viewing nights so I'm sure you'll find something to suit you.
I'm a member of the AAQ but BAS is on the northside so may be most convenient for you.

Ken.
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Old 02-07-2012, 09:05 PM
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Quote:
Originally Posted by h_ngm_n View Post
But it was a lot blurrier than the 20mm.
Probably that was what's called "seeing" - basically, the limit of magnification due to atmospheric disturbances. Typically, it's limited to 150-200x, but you may get around 300x on a really good night.
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Old 04-07-2012, 11:55 AM
h_ngm_n (Will)
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HI Brian did you get my PM?
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Old 04-07-2012, 12:37 PM
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Quote:
Originally Posted by h_ngm_n View Post
HI Brian did you get my PM?
No I did not Will , look for a flashing flag top right hand of any open page of IIS's site .
Have PM'd you .
Brian.
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