Starter equipment advice

[vlaiv]

2 minutes ago, AstroMuni said:

True. I think at this rate we are now getting into the realms of 3d printer vs laser cutter, so needs a new thread 🙂

Actually, I have my eye on desktop CNC router.

Properly built one will cut aluminum with some precision

Then there is always need for small precision lathe as well - all those T2 / M48 adapters ....

 

[900SL]

19 minutes ago, Adam J said:

Ok, I dont believe a word Trevor says either.  But you can believe me.  I have a SW AZEQ6 GTI and that is a good mount, I had a SW HEQ5 Pro and that was a good mount, I have a AZ GTI and thats a good mount (for the price) and I now have the SW SA GTI and its great too of all my mounts probably the best I have owned out the box without tuning. 

Adam 

 

I'm sure there are good ones out there, and to be fair the mounts appear to do the job after a bit of fettling, tuning, belt drive conversions etc. I did actually recommend the HEQ5..

It's just that I do know something about manufacturing and machining and tolerances and metallurgy, and the SWSA2 was pot metal junk when I opened it up..  So no SW products for me.

[Elp]

I've always wanted a pocket nc one. Think of all the machining possibilities.

I had a star adventurer, the only reason I didn't like it is its lack of goto. Different manufacturers have their own levels of QC unfortunately rather than working to a common standard, even an ISO certificate doesn't mean anything these days. There's a reason certain mounts cost as much as they do.

Edited November 17, 2022 by Elp

[vlaiv]

2 minutes ago, 900SL said:

It's just that I do know something about manufacturing and machining and tolerances and metallurgy, and the SWSA2 was pot metal junk when I opened it up..  So no SW products for me.

Indeed.

I once had SW tube ring crack. In fact - it saved the scope. I dropped the scope by accident when fiddling with the mount as one does, and I quickly put my foot under it to soften the fall (not sure where I've got that reflex - but its not very good one. I wonder if brain can autonomously judge the weight of falling stuff and decide not to try to soften the fall of say 20kg rock :D).

In any case, scope did hit the floor and my foot simultaneously and it actually hit tube ring first where it hit floor tiles - which as enough to split that ring into several parts.

They call it aluminum ring (or maybe they don't and it was just my expectation for it to be aluminum) - but it more looked like slag that was removed from melting aluminum then metal itself. It certainly looked like some industrial process byproduct rather than pure metal (and pure metal would not crack like that).

[Adam J]

8 minutes ago, 900SL said:

I'm sure there are good ones out there, and to be fair the mounts appear to do the job after a bit of fettling, tuning, belt drive conversions etc. I did actually recommend the HEQ5..

It's just that I do know something about manufacturing and machining and tolerances and metallurgy, and the SWSA2 was pot metal junk when I opened it up..  So no SW products for me.

Yeah but you have to balance that against what you expect it to do. Its for guiding lenses of 200mm or less focal length. Not really intended for telescopes, although some do try and push it to that, that is their call.  

For the most part peek errors of 4 arc-seconds are viable in that use case. Making it more precise will raise the cost and might not actually give you better results. 

Adam

[vlaiv]

3 minutes ago, Adam J said:

Yeah but you have to balance that against what you expect it to do. Its for guiding lenses of 200mm or less focal length. Not really intended for telescopes, although some do try and push it to that, that is their call.  

For the most part peek errors of 4 arc-seconds are viable in that use case. Making it more precise will raise the cost and might not actually give you better results. 

Adam

I would not mind nicely designed and machined aluminum mount with same / similar performance, instead of cast "something" housing.

 

 

[AstroMuni]

13 minutes ago, vlaiv said:

They call it aluminum ring (or maybe they don't and it was just my expectation for it to be aluminum) - but it more looked like slag that was removed from melting aluminum then metal itself. It certainly looked like some industrial process byproduct rather than pure metal (and pure metal would not crack like that).

I was recently speaking to a friend who works in the metal casting industry and he was saying that most of the products these days are from recycled metal. In the case of the OTA tube rings they certainly look as if made from cast or wrought iron (not Aluminium). Need to check with a magnet 🙂

Edited November 17, 2022 by AstroMuni

[Elp]

7 minutes ago, vlaiv said:

It certainly looked like some industrial process byproduct rather than pure metal (and pure metal would not crack like that).

Likely die cast from low silicon aluminium alloy or non spec alloy. An aluminium billet for machining would be different but more expensive process. My SW extension pier has bad porosity in it but it's fit for function so it was allowed to go into the product. Again, a QC thing. It can be a lottery buying astro stuff.

[900SL]

24 minutes ago, vlaiv said:

Actually, I have my eye on desktop CNC router.

Properly built one will cut aluminum with some precision

Then there is always need for small precision lathe as well - all those T2 / M48 adapters ....

 

That would be a good thread (thread, geddit?) to start.. home machining for the hobby astronomer

 

 

[vlaiv]

I just remembered that I still have piece of that tube ring left, so we can inspect it and if someone could guess the material @900SL ?

It certainly looks more like some sort of rock then metal

 

[vlaiv]

Under magnifying glass - it certainly looks like some sort of sand/aluminum mix with actual aluminum just being very thin coat on the outside - you can see that bit in the image here:

under hand it feels like rough stone rather than anything metallic

[900SL]

12 minutes ago, Adam J said:

Yeah but you have to balance that against what you expect it to do. Its for guiding lenses of 200mm or less focal length. Not really intended for telescopes, although some do try and push it to that, that is their call.  

For the most part peek errors of 4 arc-seconds are viable in that use case. Making it more precise will raise the cost and might not actually give you better results. 

Adam

I was getting 50 arc sec PE unguided, so was throwing away half the subs, when combined with the poor tolerances and slop in the wedge and mount. I ended up shimming and tweaking most of it but it was a poorly manufactured and assembled box made out of poor quality materials.

A friend had an iOptron tracker which was much better in terms of electronics, materials and machining, APART from the worm gear which had to be lapped and appeared to have been made somewhere else entirely. It's a bit of a QA lottery with Chinese stuff, but if you want the good stuff you have to pay for it I guess.

[900SL]

1 minute ago, vlaiv said:

Under magnifying glass - it certainly looks like some sort of sand/aluminum mix with actual aluminum just being very thin coat on the outside - you can see that bit in the image here:

under hand it feels like rough stone rather than anything metallic

Brittle pot metal casting by the looks of it

[vlaiv]

2 minutes ago, 900SL said:

Brittle pot metal casting by the looks of it

Needed to look up what the pot metal actually is - but yes, it makes perfect sense.

[Elp]

The formation of the internal metal structure has more to do with than just the metal used. Material velocity, pressure, cooling, material turbulence, air within, gate size, material temperature all have a part to play. If none of these are controlled it results in poorly made parts which you tend to see in companies which don't implement the required quality controls.

Unfortunately most products are sourced from such companies. That's why a good company will carry out their own further testing or make the components themselves, all of which adds to the cost.

Hence back to topic why I recommend an azgti for cost Vs performance.

Edited November 17, 2022 by Elp

[allworlds]

On 15/11/2022 at 13:40, imakebeer said:

I had a look the other day at the AstroBackyard reviews for the Star Adventurer 2i, and then the Star Adventurer GTi - he seemed to think the 2i was OK but had some flaws (ISTR it only tracks in RA) but the GTi pretty much addressed all of these points.

For me as a newbie the tantalizing thing is that there are AZ GTi bundles of mount + scope for quite a bit less than buying them separately (use the difference to buy the wedge!). It begs the question whether SW will release similar bundles based around the SA GTi 🙏🙏🙏

Sure, this setup is still quite limited in weight capacity and probably ultimately not as good as a ligger/better scope on an HEQ5/EQ6 GOTO but it's probably a good deal more grab & go-able and still a big step forward from my own current setup.

It's certainly something I'll consider...

Keep in mind that the Skywatcher packages tend to come with cheaper tripods, whereas if you buy a mount+tripod without scope the tripod is usually a higher quality one.

The OTAs are sometimes “cheaped out” too. Notable with the Skymaxes - lighter rolled steel tube and no user collimation on the package version, vs higher quality tube and collimation screws when you buy the OTA by itself.

[Zermelo]

6 hours ago, allworlds said:

The OTAs are sometimes “cheaped out” too. Notable with the Skymaxes - lighter rolled steel tube and no user collimation on the package version, vs higher quality tube and collimation screws when you buy the OTA by itself

Can you provide some links to show different versions of the Skymax, according to whether it's in a bundle or not?

 

6 hours ago, allworlds said:

Keep in mind that the Skywatcher packages tend to come with cheaper tripods, whereas if you buy a mount+tripod without scope the tripod is usually a higher quality one.

That would come down to whether you choose to buy the same tripod as the one in the package. Or are you suggesting that SW have different variants of each tripod, too, for bundled/unbundled sale?

 

[vlaiv]

10 minutes ago, Zermelo said:

Can you provide some links to show different versions of the Skymax, according to whether it's in a bundle or not?

Note absence of collimation screws in bundled version:

also front corrector holder is differently shaped

This is not exclusive to skymax - newtonians bundled with new line of mounts - like 130mm model, come without collimation screws as well.

(notice absence of collimation screws at the back).

[Zermelo]

2 minutes ago, vlaiv said:

This is not exclusive to skymax - newtonians bundled with new line of mounts - like 130mm model, come without collimation screws as well.

Yes, I was aware of that one - I own a SW Newtonian without (primary) collimation.
I wasn't aware of different versions of Skymax (except for the positioning of the finder shoe). And these have different tube thicknesses too?

 

[vlaiv]

38 minutes ago, Zermelo said:

Yes, I was aware of that one - I own a SW Newtonian without (primary) collimation.
I wasn't aware of different versions of Skymax (except for the positioning of the finder shoe). And these have different tube thicknesses too?

 

Don't know. I have one with collimation screws.

I specifically wanted that one so I purchased it as OTA while getting AZ-GTI at the same time (so it would have made sense to purchase bundle - but I did not want to not to be able to collimate scope in case of need).

[allworlds]

The OTA vlaiv and Zermelo have discussed. When I asked FLO they confirmed the Starquest version of the 102 Mak isn't user-collimatable, not that Mak-Casses are likely to need it. Here's the Cloudy Nights folks getting up in arms about it and also describing a possible workaround, https://www.cloudynights.com/topic/732639-no-collimation-screws-on-skywatcher-102-mak/

On the tripods, I'm just going by the photos. "Box section" aluminium tripod legs in the package: https://www.firstlightoptics.com/maksutov/sky-watcher-skymax-102s-az-pronto.html versus round aluminium legs (and an extension pillar) when bought as mount+tripod alone: https://www.firstlightoptics.com/sky-watcher-az-pronto/sky-watcher-az-pronto-alt-azimuth-mount-tripod.html

I think Skywatcher don't do that on the AZ-GTi ones actually, but I'd still urge checking before buying.