42 replies to this topic

[hatflyer]

I have the abover mount. It says the weight limit is 11 pounds. I'm considering getting a scope that would result in a load of 10-11 pounds. Is that too much?

[Tapio]

If you are thinking doing astrophotography then I say yes.

[vtornado]

What kind of scope?  Cat?  Refractor?

 

I was running a C6 on mine.  I think that is around the limit.

[hatflyer]

What kind of scope?  Cat?  Refractor?

 

I was running a C6 on mine.  I think that is around the limit.

A refractor of 6.6 lbs with a DSLR of 1 pound, and a guider (<1 lb), CW (2.4 lbs farther from the central point than the scope).

[cst4]

Can't speak for the stock tripod because I use an AZ-GTi on a sturdier Bogen 475, but the mount can carry 11 lbs like it claims.  My C6 with rings/handle/2" accessories weighs over 10 lbs and it does fine on it.  Carries my 4" F/7 refractor very solidly.  I've ran a 14 lb 8" cassegrain on mine and it did the job but you could tell that was pushing the gears... so only did that a time or two.  My GTi also has a heavier 6" vixen saddle on it... 

[jesco_t]

It all depends on what you want to do and the answer can range from "yes, no problem" to "hell, no". My take on the answer is yes, if you're just looking for visual, don't mind counterweights even in az mode and have a suitable tolerance for vibration. And the answer is no, if you're planning on imaging in eq mode.

 

The mount itself, even with the stock tripod, is mechanically able to carry even more than 5 kgs. This here is with my C8, just after I bought it a few years ago. It slews & tracks acurately, but it's wobbly and unbearably even for visual use. I only had the C8 on it for a few days until a more sturdy mount arrived in the mail.

 

 

Jesco

[hatflyer]

It all depends on what you want to do and the answer can range from "yes, no problem" to "hell, no". My take on the answer is yes, if you're just looking for visual, don't mind counterweights even in az mode and have a suitable tolerance for vibration. And the answer is no, if you're planning on imaging in eq mode.

 

The mount itself, even with the stock tripod, is mechanically able to carry even more than 5 kgs. This here is with my C8, just after I bought it a few years ago. It slews & tracks acurately, but it's wobbly and unbearably even for visual use. I only had the C8 on it for a few days until a more sturdy mount arrived in the mail.

 

 

 

Jesco

This is for photography in EQ mode. I have my own, more sturdy tripod. So a no go with 11 pounds then?

Edited by hatflyer, 09 November 2022 - 10:22 AM.

[jesco_t]

For imaging the AZ-GTI is a bit hit'n'miss even with lighter scopes, so I would not do that. 5-6kg is already a pretty serious load. Do yourself a favor and get a mount in the 10-15kg range. You'll be a lot happier.

[hatflyer]

For imaging the AZ-GTI is a bit hit'n'miss even with lighter scopes, so I would not do that. 5-6kg is already a pretty serious load. Do yourself a favor and get a mount in the 10-15kg range. You'll be a lot happier.

I've been able to track fairly well with 7 pounds (90 seconds exposure). I was considering a 560mm scope, which weighs 6.8 lbs. I may have to settle for a smaller, lighter 1 then.

[Tapio]

A long refractor is harder for mount than short SCT of equal weight (because of momentum arm). On the other hand shorter focal length is more forgiving.

 

Note that CW is usually not included in the mount's weight limit.

[MarkMittlesteadt]

I used my deforked ETX125 on it no problem. 12.4 lbs. total...

 

 

I now use it like this (my AT72ED-II, with my ST80 as a counterweight  )...

 

Edited by MarkMittlesteadt, 09 November 2022 - 11:45 AM.

[hatflyer]

I used my deforked ETX125 on it no problem. 12.4 lbs. total...

 

 

I now use it like this (my AT72ED-II, with my ST80 as a counterweight  )...

 

That's in Alt/Az mode, right? I would think in EQ mode it would be harder to handle?

[MarkMittlesteadt]

That's in Alt/Az mode, right? I would think in EQ mode it would be harder to handle?

I only use it in Alt-Az mode. In EQ mode, you'd need a CW anyway. I hate dealing with counterweights, which is why I only use Alt-Az mounts now. Any EAA or AP I might do is just short exposure. 

[Markovich]

I have a Skywatcher 130PDS mounted on mine with good results. I replaced the flimsy tripod with a Skywatcher stainless steel tripod and also upgraded to a William Optics wedge...pretty darn solid.

[hatflyer]

I have a Skywatcher 130PDS mounted on mine with good results. I replaced the flimsy tripod with a Skywatcher stainless steel tripod and also upgraded to a William Optics wedge...pretty darn solid.

So what else is loaded on the mount besides the scope? A camera? Counter-weights? What is the total load then?

 

Yeah, likely going to get the WO wedge. The SW 1 is loose. Better tripod as well.

[dciobota]

This is for photography in EQ mode. I have my own, more sturdy tripod. So a no go with 11 pounds then?

So I used a setup close to what you describe: at65edq (~5lb), asi2600mc camera (~2lb), asiairpro+30mmf4 guidescope+asi290mm (~1lb).  With a counterweight, the setup did ok, although the guiding was around 1.2-1.5arcsec rms.

 

One thing to keep in mind is the focal length you will image at.  At that payload and focal length (420mm), as I mentioned the guiding did suffer at times, so I did have to throw out frames due to star elongation.  This would not be as much of an issue if you imaged with a shorter focal length scope.  So that is something to consider.

 

Oh btw, the counteweight does not count towards your payload.  And I personally would use a heavier counterweight set closer to the mount rather than a lighter one farther out, due to momentum (which affects strain on the motors).

Edited by dciobota, 09 November 2022 - 02:28 PM.

[hatflyer]

So I used a setup close to what you describe: at65edq (~5lb), asi2600mc camera (~2lb), asiairpro+30mmf4 guidescope+asi290mm (~1lb).  With a counterweight, the setup did ok, although the guiding was around 1.2-1.5arcsec rms.

 

One thing to keep in mind is the focal length you will image at.  At that payload and focal length (420mm), as I mentioned the guiding did suffer at times, so I did have to throw out frames due to star elongation.  This would not be as much of an issue if you imaged with a shorter focal length scope.  So that is something to consider.

Currently I have a Nikon 400mm lens, tho I set it to f/8 or f/11. The load is several pounds less, and tracking goes fairly well (90 seconds or so). Not sure if the higher load would make that much more difficult. Anyway, I was of the impression an f/6 430mm scope would improve results.

[Markovich]

So what else is loaded on the mount besides the scope? A camera? Counter-weights? What is the total load then?

 

Yeah, likely going to get the WO wedge. The SW 1 is loose. Better tripod as well.

A ZWO ASAIR Plus and a ZWO ASI294MC Pro camera..I have a 2.5 lb counterweight as well.

 

The Williams Optics wedge is nice except for one thing.. the adjustment knobs, especially for altitude are too small. Difficult get any torque on them.

[dciobota]

Currently I have a Nikon 400mm lens, tho I set it to f/8 or f/11. The load is several pounds less, and tracking goes fairly well (90 seconds or so). Not sure if the higher load would make that much more difficult. Anyway, I was of the impression an f/6 430mm scope would improve results.

Oh I see.  Yes, depending on which scope you will get, it should be an improvement for astro work, especially being an f6.  

 

I'm assuming you're currently guiding?  Then if you get reasonable stars from the 400mm lens now (as far as trailing), then it's possible you qill be just fine with the scope.  The difference that the extra weight makes is strain on the motors and increased flexure in the system.  The more weight a mount carries the more it is prone to flex, and also the extra force the motors require to move the mount usually translates into slugishess in guiding response.  Therefore, guiding gets a bit worse.

 

Another issue with some azgti's is the weak clutches that can slip as you approach the limit of payload.  You'll have to be very careful to get the balance just right to avoid that slippage.

 

Do you have to throw away any subs now due to trailing?

[hatflyer]

Oh I see.  Yes, depending on which scope you will get, it should be an improvement for astro work, especially being an f6.  

 

I'm assuming you're currently guiding?  Then if you get reasonable stars from the 400mm lens now (as far as trailing), then it's possible you qill be just fine with the scope.  The difference that the extra weight makes is strain on the motors and increased flexure in the system.  The more weight a mount carries the more it is prone to flex, and also the extra force the motors require to move the mount usually translates into slugishess in guiding response.  Therefore, guiding gets a bit worse.

 

Another issue with some azgti's is the weak clutches that can slip as you approach the limit of payload.  You'll have to be very careful to get the balance just right to avoid that slippage.

 

Do you have to throw away any subs now due to trailing?

Yes, I am guiding. I don't throw too many subs away. Either it works or doesn't (usually about 75 sec subs). But with added load I guess things could get dicier.

[hatflyer]

Oh I see.  Yes, depending on which scope you will get, it should be an improvement for astro work, especially being an f6.  

 

I'm assuming you're currently guiding?  Then if you get reasonable stars from the 400mm lens now (as far as trailing), then it's possible you qill be just fine with the scope.  The difference that the extra weight makes is strain on the motors and increased flexure in the system.  The more weight a mount carries the more it is prone to flex, and also the extra force the motors require to move the mount usually translates into slugishess in guiding response.  Therefore, guiding gets a bit worse.

 

Another issue with some azgti's is the weak clutches that can slip as you approach the limit of payload.  You'll have to be very careful to get the balance just right to avoid that slippage.

 

Do you have to throw away any subs now due to trailing?

I found a scope, Tecnosky APO 70/420, that weighs just 4.1 pounds. If my set-up works with my 400mm camera lens, adding just 1.5 pounds more may be ok?

[hatflyer]

A ZWO ASAIR Plus and a ZWO ASI294MC Pro camera..I have a 2.5 lb counterweight as well.

 

The Williams Optics wedge is nice except for one thing.. the adjustment knobs, especially for altitude are too small. Difficult get any torque on them.

 

Is there room on the end of the altitude knob to add some thickness to it to get better torque?

[Markovich]

Is there room on the end of the altitude knob to add some thickness to it to get better torque?

Yes, looks like plenty of room.

[dciobota]

I found a scope, Tecnosky APO 70/420, that weighs just 4.1 pounds. If my set-up works with my 400mm camera lens, adding just 1.5 pounds more may be ok?

I've not heard of that brand, but honestly from the specs that looks like a very nice scope for the money.  And only 4.1lb is amazingly light for a triplet.  I would say yes, that's a good choice to go with.  You may still see some residual aberration at the edges (even triplets are not perfect), but there are usually flatteners that will fix that.  I don't know which flattener will work best with that scope, but even as is, it should be better I think than the 400mm lens.

 

But again, take my advice with a grain of salt since I don't know anything about that particular scope.  Might be worth asking in the refractor section, someone there might have experience with it.

 

PS, I see product not available, are you sure you can still order one?

Edited by dciobota, 10 November 2022 - 12:36 PM.

[hatflyer]

I've not heard of that brand, but honestly from the specs that looks like a very nice scope for the money.  And only 4.1lb is amazingly light for a triplet.  I would say yes, that's a good choice to go with.  You may still see some residual aberration at the edges (even triplets are not perfect), but there are usually flatteners that will fix that.  I don't know which flattener will work best with that scope, but even as is, it should be better I think than the 400mm lens.

 

But again, take my advice with a grain of salt since I don't know anything about that particular scope.  Might be worth asking in the refractor section, someone there might have experience with it.

 

PS, I see product not available, are you sure you can still order one?

Yes, it's still available in 2 shop in Europe. I saw a good review on You Tube. Otherwise, not much. I can't help but wonder why this triplet is so lightweight and low cost, even with FPL53 glass.