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$25 Dobbie Deal on OfferUp?

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16 replies to this topic

#1 CleanSkies

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Posted 18 July 2019 - 11:48 AM

https://offerup.com/...tail/697189996/

 

Mirror looks cruddy but can't tell if it's front moldiness or back deterioration.

 

It's either a great deal or a big dusty pile of parts.   Thoughts?



#2 SeattleScott

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Posted 18 July 2019 - 11:59 AM

Either oxidation or fungus. Hard to tell without a closeup. Not good either way. Basically factor recoating the mirror into the price. Note that the ad is a month old and no one has jumped on it.

If nothing else the eyepieces are probably worth $25.

Scott
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#3 Jon Isaacs

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Posted 18 July 2019 - 12:27 PM

My thoughts:

 

For $25, it's hard to go wrong.  Very likely the mirror needs a recoat but there is some chance it might clean up... And even as nasty as it looked, it probably provides surprisingly decent views.

 

I'd start with the Cary of Optical Wave Laboratories cleaning technique, that's what I use with my mirrors.  

 

https://www.youtube....h?v=9Y8xFnXFVGQ

 

Spectrum Coatings is in Deltona Florida so you could get a good recoat there.

 

https://www.spectrum...ings.com/prices

 

Jon


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#4 SeattleScott

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Posted 18 July 2019 - 12:41 PM

Last time out I demonstrated something with a new stargazer who was out with me. At the end of our session I told him to look at the Moon again with his 8” Dob. Then I told him to put his hand in front of the scope. He was astonished that he couldn’t tell any obvious difference with his hand blocking the light from entering the scope. Now when his friend stuck his whole head in the way and blocked the entire aperture, the view went dark. But just a hand blocking maybe 60% of the aperture didn’t make a readily noticeable difference in the view. Granted results might be different with faint fuzzies. So yes the scope can still function with the mirror in that condition. The ideal buyer would be someone who wanted to give stargazing a shot in order to gauge interest without spending significant money, and lives in Miami. If they get the bug they will want to recoat or upgrade to something better soon, but they could try out stargazing at minimal cost.

Scott
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#5 mfoose

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Posted 18 July 2019 - 01:02 PM

Worth the $25 for the mirror and parts. 

 

Unfortunately, it does not look like this scope was stored well. Yes, the mirror needs a recoat, but there could be issues with the base and tube as well. The base is chipboard covered with laminate and the tube is cardboard. Not sure how operational it is. I purchased a Dob once that was stored in a shed. The mirror looked a little like the one in the link and base had issues. The ground board was completely warped from the moisture and it would rub on the underside of the base when spun. I still bought it and plan to redo the base. For the time being I simply flipped the orientation of the ground board switching the feet and bearings to the opposite side and it is functional, but not great. 

 

Just something else to factor in. 


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#6 Jon Isaacs

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Posted 18 July 2019 - 01:08 PM

To my eye, the base and the tube look fine.  If the tube were delaminating, the overlapping spirals would be failing.  

 

Dobs are tough scopes.  
 
Jon

 



#7 Richie2shoes

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Posted 18 July 2019 - 02:44 PM

For $25, I'd go for it.



#8 kfiscus

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Posted 18 July 2019 - 03:18 PM

You'd be foolish to not buy it.



#9 Volvonium

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Posted 18 July 2019 - 03:35 PM

Absolutely worth it for $25.  Even if that mirror is oxidized it will still gather enough light to provide a decent view.   I bought a 10" Lightbridge with a mirror that was similarly deteriorated for $150, but it was still a great deal.  For $25, this is a steal-- the tube is in good shape and the base doesn't look bad/warped either.  Fixing any issues with altitude and azimuth movement on that would be fairly simple.  As long as there are no scratches on the mirror, you should be good.  It looks like it was just stored in humid conditions, but not humid enough to really warp the base.  



#10 SeattleScott

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Posted 18 July 2019 - 11:23 PM

It just really depends on how close you are. I have driven minutes to hours to get used scopes. If you are 20 minutes away and could use an 8” scope, sure, might as well check it out. If you are an hour or two away, I might pass and let someone closer get it.

Scott

#11 CleanSkies

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Posted 19 July 2019 - 01:40 PM

All good points, thanks fellas.  I'm in the market for a nice Mak to take to dark campsites but came across this dob.  Figure it wouldn't be terrible for backyard work at that price.

 

It's about a half-hour from me (with no traffic) in the wrong direction thru town so I'll need to see when I can squeeze in the trip outside of traffic hours (which is never, heh).   Let me see what I can do this weekend if the guy is available.

 

Any particular things I should look for?   Or for $25 just grab the thing and go?


Edited by CleanSkies, 19 July 2019 - 01:41 PM.


#12 Richie2shoes

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Posted 19 July 2019 - 02:22 PM

All good points, thanks fellas.  I'm in the market for a nice Mak to take to dark campsites but came across this dob.  Figure it wouldn't be terrible for backyard work at that price.

 

It's about a half-hour from me (with no traffic) in the wrong direction thru town so I'll need to see when I can squeeze in the trip outside of traffic hours (which is never, heh).   Let me see what I can do this weekend if the guy is available.

 

Any particular things I should look for?   Or for $25 just grab the thing and go?

I'd make sure the mount/base is in o.k. shape, no warping or in the case of particle board, no water damage.  Other than that, you already know the mirror is a mess, so just grab and go.



#13 mjulihn

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Posted 19 July 2019 - 07:12 PM

I'd make sure the mount/base is in o.k. shape, no warping or in the case of particle board, no water damage.  Other than that, you already know the mirror is a mess, so just grab and go.

Agree. Get a new primary and you may be good to go.



#14 Jon Isaacs

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Posted 19 July 2019 - 07:34 PM

Agree. Get a new primary and you may be good to go.

 

The primary can be recoated for well under a $100... 

 

No need to buy a new one. 

 

Jon



#15 joseph07081

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Posted 19 July 2019 - 08:31 PM

If I were in the area, I would not even think twice about getting it. Worst case, the parts are worth more than the asking price. It could be the basis of a cool restoration project.



#16 watchplanets

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Posted 21 July 2019 - 12:28 PM

25 is like 3 subs at subway just the parts are worth more.



#17 CleanSkies

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Posted 22 July 2019 - 09:12 AM

Well, looks like this one got away before I could get to it.  I had made contact, was working on meetup details and poof.  Gone.

 

No biggie, what I'm really after is a Mak for campground and home usage.   I had come across that Dob and figured would be nice for the backyard.  

 

Anyhow, this LX200 showed up, not sure how much of a deal it is but seems like a substantial package:

 

https://offerup.com/...tail/716777317/

 

This one may be overkill for an advanced beginner but deals is deals, right?   The goal was say an ETX105 or 125.  This of course is a big step up.

 

EDIT:   Also now sold, within hours of listing.  Was likely a good deal.  The search continues!


Edited by CleanSkies, 22 July 2019 - 01:37 PM.



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