Mount for SW StarTravel 102mm?

[pregulla]

Hi All,

I have decided to get a fast achromat to complement my dobs for low power wide field views. The SW Startravel 102mm seem like a perfect choice . I plan to get 2" diagonal for it and use it with 35mm Aero ED eyepiece (about 360g).

The question is what mount would be the best choice? I plan on buying from Europe, since buying locally is way too expensive and options are very limited. The options I have thought about:

 - OTA+AZ3 bundle, about 270 EUR. Cheapest option, but AZ3 seems like not the best fit for purpose. From what I understand it goes out of balance at higher altitudes and gets inconvenient to use. I may still get the package and upgrade later if I don't like it. The problem is I'll have to pay for shipping again. 

- OTA+AZ4/AZ5  with aluminum tripod. about 400 EUR

- Getting separately the OTA, AZ5 and stainless tripod: About 490 EUR. 

- AZ5 Shipped separately if I want to upgrade from AZ3: 257/288 EUR with Al/SS tripod

- SS tripod shipped alone - 143EUR

I am leaning towards getting the AZ5 with Al tripod. Should be fine for the Startravel 102. Upgrading to SS later will cost 50 EUR more than buying it straight away, but I will have the Al tripod too, so not too bad.

Any comments? Are there other options that I am missing? Maybe there is a different OTA that comes with better tripod and would make a better deal as a package (Something around 100mm F/5 - F/6, 2" focusser)?

[vlaiv]

Don't get AZ3 - I had that exact combo and later switched to AZ4 on steel legs.

Very big improvement. AZ3 has couple issues that annoyed me quite a bit. Stiff to move telescope by hand (although there are adjusters - it is not very smooth mount). Slow motion controls needed rewinding after a bit of use - they are not 360 degrees but rather section of the circle so you when you reach the end - you need to move scope manually and "unwind" slow motion control back to middle (if you plan to pan around slowly) or all the way if it is only for tracking single object.

Looking at zenith was next to impossible on that mount.

If you want slow motion controls then AZ5 is better option than AZ4. With AZ4 it is pretty much only feature that is missing (and I believe AZ5 is slightly lighter).

 

[A McEwan]

AZ4 is great with it.

AZ3 (modified with counter-weight) is also great, but it really needs the modification.

AZ5 I don't know as I haven't had one.

 

[Paz]

I would say not an az3 for the reason you have noted already. However a 4 or 5 would be fine.

[pregulla]

OK, AZ3 is out of the question then. Turns out Telescope-Express were underestimating shipping costs for AZ4 (it's like 100 EUR extra), so AZ4 doesn't fare well against AZ5 price-wise.

Looks like AZ5 is the way to go.

[Bobby1970]

I used to use the ST102 on a vixen porta II. Was a great combo in my opinion. 🙂

[Cosmic Geoff]

I use my ST102 with a steel legged AZ-4 which is very solid and does not wobble at all. It complements a widefield scope well. Also with a Celestron SLT mount (alter a trivial mod to the dovetail bar)

Apparently the AZ-5 can be had with a choice of tripods - a lightweight but wobbly aluminium and a steel one similar to that of the AZ-4.  Your choice.  The weight rating is said to be higher with the steel tripod.

[pregulla]

ST120mm just shower up on a used marked locally. Comes with AZ3, but the price is right. For 120mm I feel less confident with aluminum legs, so I'll probably get AZ5 with steel legs, especially since the difference when buying just the mount (head+tripod) and not the scope combo is not that big.

[Alfian]

The  ST120 is noticeably bulkier than the 102 but will be fine on the AZ4. Dont know about the AZ5. The Aero 35mm is a nice EP but it will give a 7mm exit pupil at F5.  May be OK with nice dark skies and younger eyes than I have, just something to be aware of.

 

[pregulla]

3 hours ago, Alfian said:

The  ST120 is noticeably bulkier than the 102 but will be fine on the AZ4. Dont know about the AZ5. The Aero 35mm is a nice EP but it will give a 7mm exit pupil at F5.  May be OK with nice dark skies and younger eyes than I have, just something to be aware of.

 

The 35mm works fine in my F/5 12". I may be loosing some aperture with it, but I don't notice any negative effects. I also have ES82 30mm, but I feel it's a "little" overweght for this task.

I think on steel tripod AZ5 should be fine. On the original aluminum tripod I am afraid 120mm will be too much for it. How is the AZ4 with it's original aluminum tripod? Overall I get a feeling from all the reading that AZ5 is better with short scopes. AZ4 is sturdier and more convinient with longer scopes.

Since I am getting AZ3 with the scope anyway I may try to make it work first. I have seen reports that after balancing it was acceptable for 120mm. If I was going to pay for the mount, "acceptable" woudn't be something I want, but for a freebie I will give it a shot.

[happy-kat]

I quite like the az3, I added a counter weight to mine and use it with bolts loose enough so nudging works.

[Alfian]

4 hours ago, pregulla said:

The 35mm works fine in my F/5 12". I may be loosing some aperture with it, but I don't notice any negative effects. I also have ES82 30mm, but I feel it's a "little" overweght for this task.

I think on steel tripod AZ5 should be fine. On the original aluminum tripod I am afraid 120mm will be too much for it. How is the AZ4 with it's original aluminum tripod? Overall I get a feeling from all the reading that AZ5 is better with short scopes. AZ4 is sturdier and more convinient with longer scopes.

Since I am getting AZ3 with the scope anyway I may try to make it work first. I have seen reports that after balancing it was acceptable for 120mm. If I was going to pay for the mount, "acceptable" woudn't be something I want, but for a freebie I will give it a shot.

I've just realised that its my "old" 35mm EP that we are taling about! Glad its seeing good service. Tripod wise, I've used various mounts with both aluminium and steel tripods and without question the steel legs make a big difference when using anything other than a lightweight scope. However given that the AZ3 is part of the deal, there is no harm in using it and see how it works out.

[Alkaid]

The AZ4 suits the 102 beautifully.  Here’s a pic.

[pregulla]

So I got 120mm in the end. AZ3 is pretty solid, at least at lower powers, but the balance is an issue. The scope will nose-dive near horizon and butt-dive near zenith. And that's before even getting 2" diagonal.  Seems like it should be decent enough if I can fabricoble a ciunter weight.

[pregulla]

An update after using it for a while. For my purposes (low power wide field) AZ3 was solid enough to carry the 120mm. I added an angled arm with removable counterweight - that solved the diving near zenith issue and made the mount pretty usable, but I still needed to move the tube when going from lower to higher altitudes. 

Still I am glad I didn't go for AZ4 or AZ5 as I recently scored a used Berlebach Uni17 with GR-III head for comparable price - this thing is super smooth and solid and a pleasure to use.