460 replies to this topic

[Sky Muse]

I had been toying with the idea of trying one of these scopes out, to see what all the anti-hype is about. 

I have a soft spot in my heart for small, inexpensive 'scopes: I have (and adore) one of those 76mm f9 Newts on a yoke mount (it's actually an excellent scope. Mine's Zuhmell, the Orion SpaceProbe II variant is vastly inferior, to be avoided), one of those funky little "thermos bottle" Orion 80mm achros (shockingly nice optics), a Celestron f4 Cometron Newt (a lot of fun. Not a bad sort-of-paraboloid for the $60 I paid), a Polaris 130 f5 Newt that had a spherical(!) mirror (and ring zones and a turned edge... Now freshly fixed and parabolized , out to Majestic for coating), an Orion XT4.5 (these are excellent, one of my all-time favorite small scopes).You get the point...

With the 127 Bird-Jones, I thought I might be able figure out a way to tease out a bit better performance than is generally attributed to these scopes. So far, this thread has cured me of that interest.

I'll be very curious to see if you can somehow get the thing to attain a decent image. So far, your images remind me of the performance of that spherical f5 Newt I mentioned...

That's most interesting about the Zhumell vs. the Orion.  Incidentally, Orion sells that 130mm f/5 "Polaris, and states within its specs that the primary is a parabola...

 

https://www.telescop...pe/p/113696.uts

 

...but I'll take your word for it instead.

 

Yes, I agree: these entry-level kits are a delightful challenge and occupation.

 

It was not my intention to steer you away from it, not at all, but I had to be honest, and to a fault.  We want those first starting out to pass this sort of telescope by, and as a first and only.  Incidentally, I hold dear that the best telescope with which to begin is a long-focus Newtonian, and no more than 5" in aperture; or a short-focus if it can't be helped, save an f/4.  There is a most powerful education, and instructional, in that; a hopeful one in that it may be owned and operated successfully, and with relative ease.

 

But there's certainly nothing wrong in a more experienced amateur delving into it, and as a 12th or 33rd acquisition.  The draw to this "star box" is great indeed, given its short tube; and low price, regrettably.  Did I mention that it has a short tube, and that it may be had for peanuts; or for a club outing at McDonald's, at most?

 

I look upon the Bird as my Celestron "C5"; albeit close, but no cigar in the end; but I can always pretend.  To wit, I now have a Maksutov, and now I have a "Schmidt" to complement.  I did want to have one example of each, after all.

[Sky Muse]

By the way, during the observation of Jupiter, I was able to make out quite a respectable sharpness of the planet's equatorial bands, and despite the mis-collimated muck.

 

 

[KerryR]

That's most interesting about the Zhumell vs. the Orion.  Incidentally, Orion sells that 130mm f/5 "Polaris, and states within its specs that the primary is a parabola...

 

https://www.telescop...pe/p/113696.uts

 

...but I'll take your word for it instead.

 

Yes, I agree: these entry-level kits are a delightful challenge and occupation.

 

It was not my intention to steer you away from it, not at all, but I had to be honest, and to a fault.  We want those first starting out to pass this sort of telescope by, and as a first and only.  Incidentally, I hold dear that the best telescope with which to begin is a long-focus Newtonian, and no more than 5" in aperture; or a short-focus if it can't be helped, save an f/4.  There is a most powerful education, and instructional, in that; a hopeful one in that it may be owned and operated successfully, and with relative ease.

 

But there's certainly nothing wrong in a more experienced amateur delving into it, and as a 12th or 33rd acquisition.  The draw to this "star box" is great indeed, given its short tube; and low price, regrettably.  Did I mention that it has a short tube, and that it may be had for peanuts; or for a club outing at McDonald's, at most?

 

I look upon the Bird as my Celestron "C5"; albeit close, but no cigar in the end; but I can always pretend.  To wit, I now have a Maksutov, and now I have a "Schmidt" to complement.  I did want to have one example of each, after all.

Well... there is some confusion about the Polaris 130's. It appears that some are parabolized, and some, maybe most, are not. Mine was a poorly executed sphere, almost like it was left a little rough, with the intention that parabolizing would smooth things out. Meade's website doesn't specify, which is never a good sign. I sent Meade tech support a question, asking if my Polaris 130 was supposed to be spherical, and that I was shocked to find a spherical mirror in mine, but they didn't write me back. Some reviewers stated that their sample was parabolized, others found a spheroid. Whatever. It's parabolized now.

Edited by KerryR, 01 June 2019 - 09:43 PM.

[Sky Muse]

A work of art, 'tis...

 

 

 

I do like the back end of the mirror's stalk.  It appears to be of steel, and good steel; tempered steel hopefully.  Perhaps I won't need to epoxy a nylon washer over it.

 

 

I've seen one of those before, but where...

 

https://pics.imcdb.o...reen14h4976.jpg

 

This is interesting...

 

 

Are those active threads, or that merely decorative?  With kits like these it's hard to tell.

 

Let's find out...

 

Edited by Sky Muse, 02 June 2019 - 08:07 AM.

[Sky Muse]

Well... there is some confusion about the Polaris 130's. It appears that some are parabolized, and some, maybe most, are not. Mine was a poorly executed sphere, almost like it was left a little rough, with the intention that parabolizing would smooth things out. Meade's website doesn't specify, which is never a good sige. I sent Meade tech support a question, asking if my Polaris 130 was supposed to be spherical, and that I was shocked to find a spherical mirror in mine, but they didn't write me back. Some reviewers stated that their sample was parabolized, others found a spheroid. Whatever. It's parabolized now.

Sounds to me like they had responded to multiple complaints, and rightly so, but only on occasion.  That's not good, obviously.

 

They would've replied to me, I assure you.  Had they replied to you, I'm not certain as to the success you might've had in their shipping out just a replacement primary, and this time parabolised.

 

I have a Meade "Polaris Large Equatorial", too, and an EQ-2.  It came with a wonky DEC shaft...

 

 

The threaded shaft itself is fine.  It's the tapped hole within the head that isn't.  They wanted me to ship the entire kit back.  I persuaded them to send me a scrap mount-head instead; and its DEC shaft isn't wonky.  The RA shaft is fine, and where it really counts, but only if it wasn't for the slightly oversized bore for it.  I've got to shim that, or salvage the one from the "trophy" and to see if it's tighter.

[KerryR]

Sounds to me like they had responded to multiple complaints, and rightly so, but only on occasion.  That's not good, obviously.

 

They would've replied to me, I assure you.  Had they replied to you, I'm not certain as to the success you might've had in their shipping out just a replacement primary, and this time parabolised.

 

I have a Meade "Polaris Large Equatorial", too, and an EQ-2.  It came with a wonky DEC shaft...

 

 

The threaded shaft itself is fine.  It's the tapped hole within the head that isn't.  They wanted me to ship the entire kit back.  I persuaded them to send me a scrap mount-head instead; and its DEC shaft isn't wonky.  The RA shaft is fine, and where it really counts, but only if it wasn't for the slightly oversized bore for it.  I've got to shim that, or salvage the one from the "trophy" and to see if it's tighter.

Why's that?? ("They would've replied to me, I assure you.")
 

[Sky Muse]

Hmm...

 

 

How many would you remove?

 

This many...

 

 

...or this many...

 

 

How about this variation of that...

 

 

What about this instead, and ultimately? 

 

 

I promise I'd keep kids away from it... https://www.youtube....h?v=86ZnWc1B7W4

 

I'll have to wait until the next full Moon to decide, and ask fair Luna; along with a bunch of chanting and mumbling.

 

I happen to prefer secondary-stalks over full vanes among these entry-level kits...

 

Edited by Sky Muse, 02 June 2019 - 01:20 AM.

[Sky Muse]

Why's that?? ("They would've replied to me, I assure you.")
 

Because they had in fact, albeit regarding the "Large Equatorial".  But I do think that a replacement primary, and one parabolised, would be more difficult to obtain, but not impossible.

[Sky Muse]

Here goes nothing...

 

 

I hope I didn't mean that literally.

[Sky Muse]

Most of the paint has been stripped, but not all.  I scraped off what I could, and wiped it down...

 

 

It's of aluminum, as you can see.  A second coat of the stripper should finish it up.

[Sky Muse]

Four coats it took in the end, particularly for the outer band; a bit "overzealous" there with the sprayer at the factory.  In the end, I coated the whole thing and placed it in a zip-lock bag for about 8 hours...

 

 

Not a bad piece of hardware, now that the paint's gone...

 

 

 

As it turns out, the hub is of anodised-black aluminum, and threaded into its bare aluminum frame.  It is also immovable, seized, with super-glue, or the threading is galled.

 

I'll be taking it out in a bit, and "play" it like a musical instrument...  .

 

What a lovely "vane"...

 

 

[Sky Muse]

 

Later, when no one's looking, I may place it into a 350° oven for about an hour.

Edited by Sky Muse, 02 June 2019 - 11:35 PM.

[Sky Muse]

Instead of placing it into the oven, within which we bake our gruel for bodily consumption, especially after I had previously treated the joint again with WD-40, I took the cowling outside, along with my mini butane-torch and a pail of water.  I went back in, but I still couldn't unscrew it with my fingers.  I then took channel-lock pliers and grasped at several points round the rim of the hub, pulled hard to the left each time, and at about the third or fourth instance, it gave...

 

 

                                                   

Edited by Sky Muse, 03 June 2019 - 07:13 AM.

[Mitrovarr]

I'm interested if you can get some decent performance out of this. Based on what I've seen from Bird-Jones scopes people bring to the club, as well as an old Meade one I picked up from a yard sale for $5, I don't think they're as bad as people say they are. It's hard to tell, though because I don't have a lot of time to fiddle with other people's scopes and the yard sale one has a severely damaged focuser that makes it hard to test with.

[Sky Muse]

I'm interested if you can get some decent performance out of this. Based on what I've seen from Bird-Jones scopes people bring to the club, as well as an old Meade one I picked up from a yard sale for $5, I don't think they're as bad as people say they are. It's hard to tell, though because I don't have a lot of time to fiddle with other people's scopes and the yard sale one has a severely damaged focuser that makes it hard to test with.

Indeed, it remains to be seen if this roulette-wheel sample has a decent primary.  I have read where some owners, at least, are enjoying their own, and on a satisfying performance-level I presume.  

 

Just imagine the percentage of these sold that have had their primary center-spotted after delivery.

 

The two major players in this are the collimation, and the fast, spherical primary-mirror.  I do have a two-year warranty on this one, incidentally, and I will make use of it if necessary.

[Mitrovarr]

Actually, I would guess the primary mirror is probably fine. I think the big optical factories are pretty good at making good spherical mirrors cheaply. My concern would be the corrector lens. It might not be well enough designed, or too cheaply made.

[Sky Muse]

Would the "corrector", actually a barlow, not be as nice as the doublet found within this one...

 

https://agenaastro.c...arlow-lens.html

 

Yes, quite good spherical mirrors...at f/7 and f/8.  Isn't the primary within these at f/4?  I can't say for certain.

[Sky Muse]

Celestron's warranty dept. would not have heard so much as a peep out of me if the cowling had arrived like this, fresh out of the box...

 

 

User: "Hello.  My secondary mirror spins around every time I touch it.  The hub, it doesn't seem to be secured."

Rep: "My apologies, sir.  It seems that you received Mr. Sky Muse's return.  He had complained about the primary mirror not being, in his words, 'up to snuff' ".

[Mitrovarr]

I would be confident in machine produced spherical mirrors even at F/4 and below. I mean, every schmidt-cass had a spherical primary at f/2 and they're usually fine. And when they're not it's usually not the figure of the primary that is the problem.

Also, the corrector lens in a Bird-Jones is at least supposed to not be a simple barlow.

Edited by Mitrovarr, 03 June 2019 - 02:48 AM.

[Sky Muse]

I would be confident in machine produced spherical mirrors even at F/4 and below. I mean, every schmidt-cass had a spherical primary at f/2 and they're usually fine. And when they're not it's usually not the figure of the primary that is the problem.

Also, the corrector lens in a Bird-Jones is at least supposed to not be a simple barlow.

I do hope you're right, despite my concerns about a telescope at this price-point, and when compared to the price-point of a Schmidt; ditto for the "corrector".

[Sky Muse]

[Sky Muse]

This material is extremely difficult to obtain, and consequently worth its weight in gold...

 

 

Mountains I had to scale.  Jungles through which I had to hack my way...

 

 

There's that phrase again.  What could it mean?

 

 

Of course I wasn't going to use wood.  

 

By the way, when screwing the hub all the way down now, it just stops, right here...

 

 

Prior to that most fortunate position, and when it had been torqued down and smothered with paint at the factory...

 

 

I have to wonder as to how many others suffer from that, perhaps contributing to the difficulty in collimating.

 

[Sky Muse]

Plodding forward and onward...

 

[Sky Muse]

I removed one of the three stalks -- not vanes, not by a long shot -- opposite of the favoured one...

 

 

The forward-facing surface of the stalks are rounded; aerodynamic, if you will...

 

 

Photons whizzing past vanes in general are like air, therefore you don't want a flat surface with sharp edges present, and to restrict the sprightly air.

 

The steel splint for the stalk to be retained was channeled, grooved...groovy...

 

 

The steel splint now fits just "okay" onto the rounded front of the aluminum stalk...

 

 

But I want it to fit even tighter, snugger.  The stalk therefore was cut out, and to serve as a sanding-block.  Sanding into the night, the early morning even, I will be, I expect.

[Sky Muse]

 

I don't know if my (-)ISO9001 skills will allow me to make that joint tighter.  We'll see.