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those cheap 70/300 refractors

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81 replies to this topic

#76 xvariablestarx

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Posted 25 July 2021 - 08:12 PM

I bought, I got it.  I will not be reporting anything here except to say that it's not a very good scope but usable.  This thread is a total mess. 

 

For the record:

 

I do not write book reports, I write equipment reviews.  I measure things, I make tests, I make observations I compare equipment, I write them up. 

 

I have time to review equipment.  I am retired and I spend between 500 and 600 hours a year observing.. That's an average of about an hour and a half every night of the year.. It actually works out to an average of 3 hours a night about half the nights of the year.  Spending a few nights with a scope like this is quite enjoyable.  It takes me back to the beginning.  Reminds me that I don't need $10,000 worth of telescope and eyepieces to have a good time.

 

Jon

 

Some personal disagreements intruded on the discussion, as far as I can judge, but I look forward to your review, either in this thread or another one.

I might look at one of these scopes if I want a short tube type refractor in the future, but I am not fooling myself about being able to use it out of the box without upgrades.
 


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#77 Jon Isaacs

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Posted 25 July 2021 - 08:20 PM

Some personal disagreements intruded on the discussion, as far as I can judge, but I look forward to your review, either in this thread or another one.

I might look at one of these scopes if I want a short tube type refractor in the future, but I am not fooling myself about being able to use it out of the box without upgrades.
 

 I would not start with one of these scopes, they have some fundamental difficulties.  

 

I recently purchased a Svbony SV25, just the OTA, diagonal and finder along with a clamshell mount.  It's a 60mm F/7 that about $60 and it seems to have considerably more potential.  I haven't had it out under the stars but during the day, it did quite well at 88x (4.8mm Nagler).  It comes with a couple of 1.25 inch Kellners which I did not get. 

 

https://www.amazon.c...s/dp/B01N2GIW37

 

Jon


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#78 xvariablestarx

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Posted 25 July 2021 - 08:29 PM

 I would not start with one of these scopes, they have some fundamental difficulties.  

 

I recently purchased a Svbony SV25, just the OTA, diagonal and finder along with a clamshell mount.  It's a 60mm F/7 that about $60 and it seems to have considerably more potential.  I haven't had it out under the stars but during the day, it did quite well at 88x (4.8mm Nagler).  It comes with a couple of 1.25 inch Kellners which I did not get. 

 

https://www.amazon.c...s/dp/B01N2GIW37

 

Jon

I will have a look at this scope soon then I hope.


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#79 Bowlerhat

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Posted 26 July 2021 - 12:22 AM

This thread is a total mess. 

I agree.

By the way, Jon, did you eventually ever try hands on the nifty 50/200mm?

https://www.cloudyni...little-50200mm/

 

apparently it got a diagonal package now:



#80 Nate1701

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Posted 26 July 2021 - 01:07 PM

I bought, I got it.  I will not be reporting anything here except to say that it's not a very good scope but usable.  This thread is a total mess. 

 

For the record:

 

I do not write book reports, I write equipment reviews.  I measure things, I make tests, I make observations I compare equipment, I write them up. 

 

I have time to review equipment.  I am retired and I spend between 500 and 600 hours a year observing.. That's an average of about an hour and a half every night of the year.. It actually works out to an average of 3 hours a night about half the nights of the year.  Spending a few nights with a scope like this is quite enjoyable.  It takes me back to the beginning.  Reminds me that I don't need $10,000 worth of telescope and eyepieces to have a good time.

 

Jon

I'm grateful for guys like Jon that take the time to use and report on scopes like this, and not only use and report - but also enjoy them for what they are.

If it wasn't for Jon i wouldn't be enjoying my 80mm F5 right now.


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#81 Gregrox

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Posted 26 July 2021 - 03:30 PM

Hi Greg, I have one as use it regularly.

They are not that bad optically. I can see Jupiter's 2 main bands and Saturn's rings easily. I use it around 60 to 70x. The moon looks nice too. It does have chromatic aberation...but being careful with focus you can get it down to were it's not that annoying. The cap has a 40mm aperture stop which give you an almost chromatic free image and only slightly dimmer.

The true aperture is closer to 60/65 mm. It has a light baffle near the focuser which I removed as it stopped it down a little.

The focuser was .965 but unscrewing the eyepiece holder I adapted a 1.25" diagonal and 1.25" eyepieces. Have not been able to test it at a dark site, but it should work as good as a binocular at low powers.

How pleased you will be with this scope is personal preference. People using high end 70 or 80 apo refractors will tell you these are junk. Most of the time, my seeing limits what I can see regardless of the telescope I'm using.

I have it on a light tripod which I take outside with one hand to get 15 to 30 minutes of observing time. I value this more than it's optical flaws.

Would I like to have a TV 60 or 70 pronto of course. But I don't, so I use what I have and am quite satisfied. For the low price, I figured if it was bad I'd use it a a finder on my larger scopes, but Soo far it has served me as a grab and go.

Forgot to mention that whatever tripod and eyepieces it comes with WILL be junk. Only the OTA is of any value.

I'm surprised that it ends up with almost the same aperture as the 70/400 refractors, which have a longer focal length and a wider focuser drawtube.

 

Thanks for the information. Very helpful.



#82 Taosmath

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Posted Today, 10:18 AM

Following Diego's comments on trimming the objective spacer  to improve collimation I have spent a few hours tinkering to try an improve the collimation on my Barska branded 70/300M.

 

I won't bore everyone with the 10 or so iterations of trimming & different spacers I tried.  Suffice it to say that my observations pretty much agreed with Diego's.

 

The best I got it, at 60x I could see the rings of Saturn  and the moons and one band on Jupiter. Albireo and Mizar were easy splits and I could just see the companion to Polaris.

 

On DSO's,  M13 & M22 were observable and with averted vision I could see there was some structure though I could not make out individual stars.  M4 was barely detectable in my Bortle 3.5 sky.  I could not definitely detect M81 & M82.   On open clusters M29 was surprisingly easy (probably because of lack of background stars) as was Brocchi's cluster.  M57 was not detectable.

 

The moon was pleasant up to about 50x, but the view was soft at 60x and above.

 

My opinion is that it does fine for the purpose I bought it - a low cost finder at about 12-15x, but personally I would not use it for anything else.  It was blown out of the water by the Goscope80 I use as my wide field travel/grab & go - though that scope cost me 3 times as much used.


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