Jump to content

Sketches

Review of the Orion Starblast 6.


DanyalAG
 Share

Recommended Posts

When I was first getting into astronomy, i often heard that mass-produced Synta and GSO Dobs(Orion, Celestron, Meade) were often only average in optical quality; and often mediocre(below 1/4th p-v wavefront). That is why I decided to get an OTA from Orion Optics (VX8L) which is an 8" F/6  Newtonian OTA. I built the dobsonian mount myself, and frankly have been very pleased with it. The 1/8th p-v optics are excellent on both the planets and DSOs and I've never had any issues with it.

Recently however, I wanted a smaller scope for portability and mostly to mod, and so I thought; why not go with one of these cheap scopes from Synta and GSO. I settled upon the Starblast 6, because of its decent aperture, good portability, and good value. Now, on to the review.

When the scope first arrived, I was not at all happy with it. Star-Test showed astigmatism, and images looked distinctly soft when compared to the VX8L. For some time, I thought to replace it or better yet return it... and it spent a fair amount of time gathering dust, instead of underneath the sky. I decided to give it another shot, since you should never judge a telescope on only one star-test. this time, I noticed that the star-test wasn't showing astigmatism at all, but rather pinched optics. I was a newbie to these issues as my previous scope never had any. The next day, the scope was quickly disassembled, and I decided to do away with the mirror-retaining clips permanently. I used sillicone sealant to glue the mirror to its cell, taking care not to deform it... and left it out to dry as I waited for night to settle in.

I must say that after this small fix,  this little scope performs like a dream. The star-test is almost perfect-showing no more than 1/6th p-v undercorrection( which is I think is easily acceptable for a scope this price) also I cannot detect any roughness or zones in the optics even at 320X. Epsilon Lyrae(the double double) is resolved completely at 75X-and this is a feat that I have not been able to better in the VX8L. I have tested the scope to its very limits; which include splitting 52 and 14 Orionis (1.1" and 0.92" respectively) and seeing Pluto (in Bortle 3 skies). Optically I think, that if this is the standard for all Chinese Dobs, then it is a very good standard indeed.

On DSOs, almost everything the VX8L can show me, this can also, albeit a bit dimmer and harder to see.

I have found that planetary contrast suffers a little due to the large(33%) obstruction, but this is to be expected from an F/5 instrument.

Mechanically, I really love the tube rings, as they allow me to rotate the tube for optimum focuser position, and will also allow the mounting of the scope on other mounts.

The Alt-Az motions are OK, although they could be smoother... but it again, at this price, it is hard to beat. Of course, you do need a table to set it on-but personally-as the mount saves space-I think its a non-issue.

The only thing I seriously dislike about the scope is the plastic focuser. It has an unacceptable amount of slop, and shifts focus whenever I put in a heavier eyepiece. I will probably replace it. It's really a shame... because if Orion just replaced this with a 1.25 or 2" crayford, then this would be the perfect portable telescope.

Moving on to the eyepieces, the scope comes equipped with 25mm and 10mm Sirius Plossl eyepieces. I am of the opinion that a well-made, well-coated Plossl eyepiece is a very good eyepiece... difficult to beat in terms of contrast and light-transmissivity. I have th Meade 4000 series plossls, as well as the Orion Stratus, and they are both very good eyepieces.

The Sirius Plossls are decent quality... they are fully coated, and provide around 85-90% of the performance of the Meade Plossls.

Overall, I think, the scope is pretty decent quality. It is annoying that the mirror-clips were done too tight- and I'm sure that a beginner will struggle to deal with such issues. Here are some mods you can do if you buy or are thinking to buy this scope:

1. Star-test the scope, and if its not perfect, try loosening or even removing the mirror clips( and glueing the mirror!)

2.Add a tube-extension to the front of the scope( really helps with contrast).

3. Flocking the scope.

4.Replacing the focuser(Eventually).

All in all, I think its a pretty decent scope for what its worth.

Anyways, this is my two cents on the scope. 

 

  • Like 5
Link to comment
Share on other sites


Thanks for your review.   A local clubmate of mine used to make his own mirrors to ensure optical quality.  His comprehensive workshop had all the kit needed.    But lately he’s given that up.  He’s found that ready made mirrors are surprisingly good, and far cheaper than his own.  
 

By the time he bought the blanks, various grades of the abrasives, put in a whole lot of work then paid to have the mirror aluminised, it just wasn’t worth the hassle.

So I’m not surprised you’re happy with the Star Blast.  Well done sorting the pinched optics, and hope you get a lot of pleasure from it.   As you’ve mentioned you could always upgrade the focuser.

Ed.

  • Like 1
Link to comment
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
 Share

×
×
  • 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.