What AZ mount for a Bresser 90/900 (for an 11 year old kid)?

[Luter68]

Hallo,

I have just bought a Bresser 90/900 for my 11 yo son. Now I need a mount for it.

At the beginning I though of giving him an old eq mount that I have but I now think that, besides being not such a good mount, it may just add excessive and un-necessary complication.

Thus, I am now thinking of an AZ mount. What I have seen so far are the AZ-3 and the AZ-4 (either wilh Al or steel tripod). Prices are about 100, 170, 240 (wjhatever unit, this is about how they scale).

The bresser comes with a vixen style plate. The AZ-3 would require rings or an adapter plate and I would have to add another 40-50 Euro for it. The AZ-4 would be ready to use. I also see there is a goto version of the AZ-4 at a price not too high above the AZ-4 with steel tripod.

I am also thinking now that an AZ mount could also be useful as grab an go (I have a Celestron AVX that is not exactly so).

Thus, my questions are:

1) Is there a real difference betweem AZ-3 and AZ-4 with Al tripod? I somehow think the AZ-3 could be easier to balance (but that could just be my impression.....)

2) Could anyone with a AZ-3 tell me the distance and diameter of the two mounting holes on the mounting plate (I have seen this adapter http://www.teleskop-express.de/shop/product_info.php/info/p388_Starway-Quick-release---dovetail-adapter-for-diverse-mounts.html and I would like to know whether it would fit). I would prefer this solution to mounting rings.

3) what about the goto version? does it work well? is the mount fully useable also when not using the goto and the motors (I do not want to buy a new power unit for this other mount)?

Thanks a lot for any answer you may provile.

Luca

[mikeDnight]

An AZ4 with aluminium tripod would work well. Theres no need for the steel tripod option as it will just add to the weight. They can often come up second hand relatively cheap on 'astro buy and sell'. There are no slow motion controls on the AZ4 but once the altitude and azimuth frictions have been tweaked the mount glides easily in both directions. The AZ4 is certainly a better AZ mount than the AZ3. The latter uses annoying tangent arms limiting movement and it is also weak when looking towards the zenith, and can overbalance. I regularly use an AZ4 as my grab and go mount and it works very well, even at high power. The last time i checked the AZ4 with aluminium tripod cost in the region of £130 new.

Mike

[John]

I agree with Mike. The AZ-4 is a much better choice for a long refractor than the AZ-3.

 

[Mark at Beaufort]

I bought this Celestron mount for my PST but I also used it with a 72mm ED frac. It has a capacity of 10 pounds. I have tried to find the weight of the Bresser OTA but can't find the info. If you weigh your OTA this might be an alternative and is not that expensive.

https://www.firstlightoptics.com/celestron-mounts/astromaster-tripod.html

[happy-kat]

Not sure what goto mount you mean but the skywatcher star discovery mount has freedom find, the mount I understand can be used with no power.

[Dave In Vermont]

As above, I'm with the other voices for an AZ-4. Quite smooth and manageable for an 11 year old - and even some adults, too!

I have the version of these we have here under a different name - and it works very nicely for a much heaver scope than the Bresser 90 F10. Easy to assemble and disassemble for easy moving about.

Enjoy!

Dave

[Putaendo Patrick]

I don't know the Vixen mini porta so I can't advise as to it's suitability for your son's telescope. But the larger version is great! However Teleskop Service has it on offer at 199 euros. Just a thought

http://www.teleskop-express.de/shop/pr5.oduct_info.php/info/p2933_Vixen-MINI-PORTA---Azimutal-Mount-with-tripod---friction-control---slow-movement.html

Weight up to 5.3 kg according to specs.

[Luter68]

Thanks a lot for the kind and helpful replies.

Mike and John, thanks for your views on the AZ-4 with Al tripod. I am inclined towards it as it is also pretty straightford for a kid to use.

Mark, thanks for pointing out to me the celestron one. How does it cope with objects close to the zenit (the bresser would be a longer scope than a 72 ED)?

The Bresser AR 90/900 weights 2.5 kg with accessories (http://www.bresser.de/en/Astronomy/Telescopes/Bresser-Messier-AR-90-90-900-Optical-Tube-assembly.html)

Happy-kat, the AZ goto I was referring to is this one:  https://www.firstlightoptics.com/alt-azimuth/skywatcher-az-goto-mount.html  I do realise now that likely this is not an AZ-4 although it looks similar.

[Luter68]

Thanks Patrick. I did not consider the mini porta because I read not so positive comments about it. The porta II is too expensive for the use that I intend.

[billyharris72]

I got an AZ3 supplied with an ST80 and never got on with it at all. I suspect it would handle the scope (just about) but the mount itself is just nasty. Extremely stiff in alt, whch makes coarse pointing of the scope awkward (if you loosen it off the scope falls backwards at high alt and the slow motion cables stop working - and you can't loosen and retighten in field as this needs a spanner). The aluminium legs on mine were garbage - the bolt threads for adjusting leg height were not properly cut, which mangled the aluminium thread on the mount itself. I replaced the bolt (after removing it with mole grips) but within 3-4 more uses the internal thread had cut right off, meaning I needed to use a clamp to hold the leg in place.

Replaced it with an AZ4. Not perfect, but incomparably better than the AZ3.

Billy.

[Cosmic Geoff]

I have an AZ-4 which I originally got to mount a 70mm vintage brass refractor. I have also used it with all my other scopes, except the 200p which is too big and heavy for it. 

Mine is the steel leg version, but you will, I expect, find that the alloy leg version is adequate for your purpose and lighter.  The mount is very easy to deploy - I store mine with the legs extended and don't use the eyepiece tray, so I just have to carry it outside and spread the legs. Slow-motions would be nice to have, but otherwise this is an excellent mount to have on hand for any (smallish) telescopes you might acquire in future. The stainless steel tripod is as rigid as the steel tripod of the EQ-5 (actually it's the same tripod), and two orders of magnitude more rigid than flimsy budget alloy tripods. Recommended.

[happy-kat]

@Luter68 that mount will not work without power. Only the star discovery will (or virtuoso but is way too small) zenith might be tricky though.

[Luter68]

Thanks billyharris72 and Cosmic Geoff, it will be the AZ 4! I am inclined towards the alu tripod version,  although I admit the steel tripod for just 70 euro more is tempting.... later I may get also a 130p-ds that may be a nice grab and go for darker locations. Do you think the alu tripod AZ 4 will be fine with such a scope?

thanks happy-kat, that one is now excluded too.

[John]

20 minutes ago, Luter68 said:

Thanks billyharris72 and Cosmic Geoff, it will be the AZ 4! I am inclined towards the alu tripod version,  although I admit the steel tripod for just 70 euro more is tempting.... later I may get also a 130p-ds that may be a nice grab and go for darker locations. Do you think the alu tripod AZ 4 will be fine with such a scope?

thanks happy-kat, that one is now excluded too.

 

The AZ-4 works well with  the Skywatcher 150P F/5 on it so I've sure it would cope with the 130P-DS on it.

 

[Luter68]

39 minutes ago, John said:

 

The AZ-4 works well with  the Skywatcher 150P F/5 on it so I've sure it would cope with the 130P-DS on it.

 

Thanks. Is it the Aluminum tripod version that you have?

[Dave In Vermont]

I don't claim to know how the AZ-4 reacts to very long OTA's, but I'm sure a 90mm F10 wouldn't prove to be any problem whatsoever.

Weight-wise, I'm using one to support a 150mm Maksutov-Cassegrain. These monsters were built for tank-combat in World War II between the Soviet and German armies. So it's weight is at about the outer-edge for an AZ-4 to manage. It handles it with a slight increase in vibrational stability. To overcome this, I did what would seem counterintuitive - I hung a 10lb. weight from the center-knob, past the tray/leg-spreader tray, on a 15-inch line. Now it's perfectly stable and vibration-free. A 90mm achromat at F/10 should not need any help. It weights far less than my 5kg. 150mm Mak.

That's one very handsome-looking telescope, by the way. I'd have loved to have that when I was 11! Tell him he's one very fortunate young man for me, please.

Starry Skies -

Dave

[Luter68]

On 11/24/2016 at 00:37, Dave In Vermont said:

I don't claim to know how the AZ-4 reacts to very long OTA's, but I'm sure a 90mm F10 wouldn't prove to be any problem whatsoever.

Weight-wise, I'm using one to support a 150mm Maksutov-Cassegrain. These monsters were built for tank-combat in World War II between the Soviet and German armies. So it's weight is at about the outer-edge for an AZ-4 to manage. It handles it with a slight increase in vibrational stability. To overcome this, I did what would seem counterintuitive - I hung a 10lb. weight from the center-knob, past the tray/leg-spreader tray, on a 15-inch line. Now it's perfectly stable and vibration-free. A 90mm achromat at F/10 should not need any help. It weights far less than my 5kg. 150mm Mak.

That's one very handsome-looking telescope, by the way. I'd have loved to have that when I was 11! Tell him he's one very fortunate young man for me, please.

Starry Skies -

Dave

Thanks Dave, I will certainly tell my son!

Today I did order the mount!!

Luca

[BritAngler]

Too late to advise before buying, but that's okay because you've made a good choice

I have recently bought the AZ4 as a grab-and-go mount and although I haven't had chance to use it yet (received it yesterday so cloudy nights for the next few weeks guaranteed) I'm well pleased with it.