ZEQ25 from iOptron or Avalon M-Zero for life?

I know, maybe a strange question since these two mounts play in completeley different leagues concerning AP. But I was thinking "buying a mount for life now?" or play e.g. with the ZEQ25 will suffice. I want to do AP till at least 500mm mit refractors, also the 400 f/2,8 from Nikon. And I really need a light mount since I live in a big city, 4th flour without elevator. Not even talking about taking it to foreign countries in an airplane... The Avalon is 10 kg complete and takes 8kg for AP. The ZEQ25 has the same weight plus counterwheight. The main difference seems production quality (also some huge guiding error compared to the Avalon) and the net seems "full" of people having problems with that, whereas the M-Zero you find almost nothing, maybe because there are only a few and these are too satisfied to discuss. So maybe it is wise to exercise some with the ZEQ first, sell it later, get the M-Zero. But I really would not like to mess around with the possible faults of an iOptron. I have some experience with EQ3 and some rented mounts like the GP-D2 and am sure with AP doing it for years. Maybe save money some longer and be patient and skip the cheaper one and go for the "right stuff". And the guys from that seller claims the M-Zero would even take a RC from GSO 8"... Do I sound weird? Any thoughts, experiences?

elgol20 wrote:

I know, maybe a strange question since these two mounts play in completeley different leagues concerning AP. But I was thinking "buying a mount for life now?" or play e.g. with the ZEQ25 will suffice.

I personally picked up a like new iOptron Zeq25gt with Extra Mounting Plates for ~ $650 so direct comparison to a $4,000 Mount is a good stretch but a "Fair Question" . . .

The basic "Tracking Accuracy" of ANY mount is "Extremely Dependent" on Accuracy of Polar Alignment or other Star Alignments . . . From my home in Central Oregon it's more common than not that I can't "Find" Polaris because of overcast. ( This has Nothing to Do with Mount Brands )

I want to do AP till at least 500mm mit refractors, also the 400 f/2,8 from Nikon.

This is Well Within the Range of a "Correctly Calibrated" iOptron Zeq25gt or any Guided one.

Speaking of "Guiding" that's pretty much a "Requirement" for Long Duration Extreme Telephoto 500mm + Astro Imaging . . . ( Regardless of Which Brand or Model of Mount )

And I really need a light mount since I live in a big city, 4th flour without elevator. Not even talking about taking it to foreign countries in an airplane... The Avalon is 10 kg complete and takes 8kg for AP.

"The mount weights only 6 kg/13.2 lb and, combined with the new T-Pod 90 tripod, reaches a total weight of 12 kg/26.4 lb." ( from the Avalon )

The ZEQ25 has the same weight plus counterwheight.

Zeq25gt + Pentax Q7 + Sigma 70-300mm Lens + 60mm GuideScope & Camera . . . 38-lbs
( Including a 6-Hour 12 Volt Rechargeable Power Supple / which is attached above the tray )

Above shows a 1,380mm Equivalent FOV Setup ( Guide Computer is is not shown )
Acer Netbook running Windows 7 along with Stellarium & PHD2 Guiding Software

The main difference seems production quality (also some huge guiding error compared to the Avalon) and the net seems "full" of people having problems with that,

The iOptron Zeq25gt gained a large number of Beginner / Goto Computerized Equatorial Mount users because of Positive Reviews & Conservative Pricing . . . Expert Level Setup & Calibration are "Required" for Precision Tracking Results . . .
They do have some Mfg. QC on occasion & may require "Tweaking" to get the most out of them . . . This is NOT a huge deal . . . Paul Chase made a series of YouTube Videos that Show How.

https://www.youtube.com/watch?v=K9Gb3dmjqhk Establishing Zero Point Reference on Zeq25gt

https://www.youtube.com/watch?v=YxEqeJc9L34 Guided Capabilities of the Zeq25gt

whereas the M-Zero you find almost nothing, maybe because there are only a few and these are too satisfied to discuss. So maybe it is wise to exercise some with the ZEQ first, sell it later, get the M-Zero. But I really would not like to mess around with the possible faults of an iOptron.

I did "Tweak" mine . . . This took about 90-Minutes of my time.

https://www.youtube.com/watch?v=-Cjqs4iDW1c ZEQ25 TuneUp

I have some experience with EQ3 and some rented mounts like the GP-D2 and am sure with AP doing it for years. Maybe save money some longer and be patient and skip the cheaper one and go for the "right stuff". And the guys from that seller claims the M-Zero would even take a RC from GSO 8"... Do I sound weird? Any thoughts, experiences?

If your Primary Interests are in DSLR Camera Body + Lenses Photos . . . Check out the New Pentax K3ii DSLR Body . . . It has a Built-In AstroTracer with GPS . . . It's NOT as Far-Reaching as a Dedicated Full-Blown GoTo Equatorial Mount but it Weights less than 3-Pounds TOTAL.
http://ricohimaging.com/product/k-series/k-3-ii/

Whatever you choose to do a "Good" solution for Star-Tracking is worth the time & money . . .

Trollmannx wrote:

What makes a good mount rather expensive is:

Orthogonality - the angle between the axis should be precisely 90 degrees.

Bearings - reliable precision bearings do not come cheap.

https://www.youtube.com/watch?v=tTwMIq87IyY This Video SHOWS the Bearing Quality

Gears - precision gears are not cheap, do not jump erratically and run very smooth. Depending upon the construction a well constructed gear train might have a rather large periodic error if made to be used with an autoguider or adjusted with PEC (talking smooth 5 - 10 arc second errors for good mounts - bad mounts can have 30 - 60 arc second periodic error with some unpredictable erratic jumps).

The Servo-Encoder used in the iOptron Zeq25gt has a .14 Arc-Second resolution . . . That's one of the reasons I purchased it . . . For it's price range that's as good as it gets. ( circa 2015 )

https://www.youtube.com/watch?v=YxEqeJc9L34 Zeq25gt Guided Performance / ONLY 1/10 Pixel Corrections Typical . . . I believe Paul Chase was Imaging with a 700mm Scope . . .
Actually WATCH the Video it's only 2-Minutes & 32-Seconds long

The precision needed for small gears is incredibly thight and good choice of materials are needed to get the most out of the mount. Soft materials are cheap to machine but will wear with time and this is typical for the cheaper mounts - they often get worse by time.

I owned 1/3rd of Applied Tool & Engineering in Silicon Valley & have great familiarity with "Precision" parts . . . Try building Laser Guides that are Parallel & Flat within .00001" - We built these for Lawrence Livermore Labs in the mid 80's.

So do not believe that it is possible to get a really good mount without paying - unless getting a splendid deal on a used mount in good condition.

We are ALL Prisoners of our Beliefs & Considerations of Past Experiences . . .
It's Interesting & Challenging to Sort it All Out & Not Always an Easy Task . . .
So Far I'm Happy with my Zeq25gt but Maybe Tomorrow I'll gain New Wisdom's & Will Want More.

The Uno-M is made in Italy and is a well known mount in central Europe. This is a precision mount and do not come cheap.

Typically Very True . . . But Absolutes Don't Exist ANYWHERE ! imho

I certainly agree that one needs a Very Accurate Mount . . . Depending on one's skill set, there are Different Paths & Amounts of Money Required to Achieve this end . . .

Again IF I lived in a Big City in a 4th Story Apartment without an Elevator . . .
I may get interesting in the new Pentax K3ii which has a Built-In Tracking System & Works with a Regular Light-Weight Tripod . . .
Although 500mm & 5-Minute Exposures are the MAX . . .
So far 300mm is the Longest Focal-Length shots I've seen but they appear decent . . .
https://www.flickr.com/search/?text=AstroTracer Collection of Pics taken with the AstroTracer on various models of Pentax DSLR's

( Note : If your Headed for LONG Focal Length Imaging this is not a solution )

hey thanx a lot that has already been very fruitful and yes, I guess like almost always in life there is no clear yes or no. until next time Namibia in 2017 I will have to have to final solution and be trained using it, so, well, exaclty this is what I am torn inbetween. funny those videos I have seen some months ago. fpr autoguiding I wanted to get the MGEM, well...

Trollmannx wrote:

elgol20 wrote:

hey thanx a lot that has already been very fruitful and yes, I guess like almost always in life there is no clear yes or no. until next time Namibia in 2017 I will have to have to final solution and be trained using it, so, well, exaclty this is what I am torn inbetween. funny those videos I have seen some months ago. fpr autoguiding I wanted to get the MGEM, well...

Now you are taking!

It happens all the time - someone buying some fine astronomy gear and not spending the time needed to learn how to use it. Steep learning curve and a lot of frustrations ahead but when beginning to master this is a great hobby (have been into it since pre school era).

So get a mount in good time before the critical moment and learn how to handle it in the dark. Do not get the cheapest mount around but the more expensive one migh also not be the best choice.

What makes the real difference is not the mount per se, but the one who can handle the mount and the one who is litterally lost in the dark!

yeah:-D, being lost in the dark, I like that!

I mean, when I was in Namibia this year for the first time I spent like 70 hours under these amazing stars. and I had all this experts around me, well, yeah, I guess they felt pity a bit for me since I did not truly prepare myself for years. so, I know what you mean by feeling lost in the dark, hearing the jackals howl, being like ten thousand kilometers away from home in the middle of the kalahari and feeling like you are wasting your managing nothn, with no time for appreciation&awe for the beauty of creation within all these stars and nebulas up there are all gone due to frustration and... yes, being lost. so when you think about moments like this, there is some good argument in investing some more buck sometimes ....

elgol20 wrote:

I mean, when I was in Namibia this year for the first time I spent like 70 hours under these amazing stars. and I had all this experts around me, well, yeah, I guess they felt pity a bit for me since I did not truly prepare myself for years. so, I know what you mean by feeling lost in the dark, hearing the jackals howl, being like ten thousand kilometers away from home in the middle of the kalahari and feeling like you are wasting your managing nothn, with no time for appreciation&awe for the beauty of creation within all these stars and nebulas up there are all gone due to frustration and... yes, being lost. so when you think about moments like this, there is some good argument in investing some more buck sometimes ....

Definitely use your "Time Indoors" to Setup & Learn how to use whatever equipment you End Up with . . .
However don't fall into the "Think Trap" that buying an "Expensive" mount will solve all your Astro-Imaging problems . . . That's just One Beginning to an Astro-Adventure . . .
This Hobby or Profession is one of the Most Challenging Frontiers in Photography ( One "Simple" Equation or Solution does NOT FIT ALL )

One could make the argument that the "Best" Mounts are Very Solid & Relatively Heavy . . . Their is certainly a Positive Operational Aspect to that IF You End-Up handling a Larger Scope.

This video suggests the LARGEST Scope Size the Zeq25gt may be able to handle . . .
https://www.youtube.com/watch?v=_cIOTROXEpQ 32 Lbs with a 10 Lbs Mount.

I sometimes visit & have friends that work here . . . http://www.oregonobservatory.org/ this facility hosts ~ 20 Telescopes ranging from ~ 4" Apertures up to a 30" Newtonian . . . For their "Smaller" size scopes they use Mounts that Costs in the Range of $6,500 & Up . . . NONE of Those Mounts are Portable WITHOUT a Moving-Crew . . . They are However "Rock Solid" & Highly Accurate.

btw : Your Telescope or Camera / Lens MAX Focal Lengths being used have a HUGE Impact on the "Requirements" for your Star Tracking needs.

Here's an Example of what one "City Apartment Dweller" does with his iOptron Zeq25gt Mount . . .
https://www.youtube.com/watch?v=-JZ5tgvfdOw

Orion12 wrote:

elgol20 wrote:

I mean, when I was in Namibia this year for the first time I spent like 70 hours under these amazing stars. and I had all this experts around me, well, yeah, I guess they felt pity a bit for me since I did not truly prepare myself for years. so, I know what you mean by feeling lost in the dark, hearing the jackals howl, being like ten thousand kilometers away from home in the middle of the kalahari and feeling like you are wasting your managing nothn, with no time for appreciation&awe for the beauty of creation within all these stars and nebulas up there are all gone due to frustration and... yes, being lost. so when you think about moments like this, there is some good argument in investing some more buck sometimes ....

Definitely use your "Time Indoors" to Setup & Learn how to use whatever equipment you End Up with . . .
However don't fall into the "Think Trap" that buying an "Expensive" mount will solve all your Astro-Imaging problems . . . That's just One Beginning to an Astro-Adventure . . .
This Hobby or Profession is one of the Most Challenging Frontiers in Photography ( One "Simple" Equation or Solution does NOT FIT ALL )

One could make the argument that the "Best" Mounts are Very Solid & Relatively Heavy . . . Their is certainly a Positive Operational Aspect to that IF You End-Up handling a Larger Scope.

This video suggests the LARGEST Scope Size the Zeq25gt may be able to handle . . .
https://www.youtube.com/watch?v=_cIOTROXEpQ 32 Lbs with a 10 Lbs Mount.

I sometimes visit & have friends that work here . . . http://www.oregonobservatory.org/ this facility hosts ~ 20 Telescopes ranging from ~ 4" Apertures up to a 30" Newtonian . . . For their "Smaller" size scopes they use Mounts that Costs in the Range of $6,500 & Up . . . NONE of Those Mounts are Portable WITHOUT a Moving-Crew . . . They are However "Rock Solid" & Highly Accurate.

btw : Your Telescope or Camera / Lens MAX Focal Lengths being used have a HUGE Impact on the "Requirements" for your Star Tracking needs.

Here's an Example of what one "City Apartment Dweller" does with his iOptron Zeq25gt Mount . . .
https://www.youtube.com/watch?v=-JZ5tgvfdOw

Yeah, I know what you mean. Well so far I have done it all, except the real stuff. Stacking and everything works well, just, from what you usually hear, spend most money on the mount (!). soon I will decide. the zeq25 looks really decent. waiting for an M-GEN was hard enough since Sony won't deliver sufficient sensors ...

elgol20 wrote:

Orion12 wrote:

elgol20 wrote:

I mean, when I was in Namibia this year for the first time I spent like 70 hours under these amazing stars. and I had all this experts around me, well, yeah, I guess they felt pity a bit for me since I did not truly prepare myself for years. so, I know what you mean by feeling lost in the dark, hearing the jackals howl, being like ten thousand kilometers away from home in the middle of the kalahari and feeling like you are wasting your managing nothn, with no time for appreciation&awe for the beauty of creation within all these stars and nebulas up there are all gone due to frustration and... yes, being lost. so when you think about moments like this, there is some good argument in investing some more buck sometimes ....

Definitely use your "Time Indoors" to Setup & Learn how to use whatever equipment you End Up with . . .
However don't fall into the "Think Trap" that buying an "Expensive" mount will solve all your Astro-Imaging problems . . . That's just One Beginning to an Astro-Adventure . . .
This Hobby or Profession is one of the Most Challenging Frontiers in Photography ( One "Simple" Equation or Solution does NOT FIT ALL )

One could make the argument that the "Best" Mounts are Very Solid & Relatively Heavy . . . Their is certainly a Positive Operational Aspect to that IF You End-Up handling a Larger Scope.

This video suggests the LARGEST Scope Size the Zeq25gt may be able to handle . . .
https://www.youtube.com/watch?v=_cIOTROXEpQ 32 Lbs with a 10 Lbs Mount.

I sometimes visit & have friends that work here . . . http://www.oregonobservatory.org/ this facility hosts ~ 20 Telescopes ranging from ~ 4" Apertures up to a 30" Newtonian . . . For their "Smaller" size scopes they use Mounts that Costs in the Range of $6,500 & Up . . . NONE of Those Mounts are Portable WITHOUT a Moving-Crew . . . They are However "Rock Solid" & Highly Accurate.

btw : Your Telescope or Camera / Lens MAX Focal Lengths being used have a HUGE Impact on the "Requirements" for your Star Tracking needs.

Here's an Example of what one "City Apartment Dweller" does with his iOptron Zeq25gt Mount . . .
https://www.youtube.com/watch?v=-JZ5tgvfdOw

Yeah, I know what you mean. Well so far I have done it all, except the real stuff. Stacking and everything works well, just, from what you usually hear, spend most money on the mount (!). soon I will decide. the zeq25 looks really decent. waiting for an M-GEN was hard enough since Sony won't deliver sufficient sensors ...

I would NEVER tell someone that a "Good" Mount is not "Extremely Important" . . . I would add it's FUNDAMENTAL . . . Their is however a Precision Mount Aspect that is often Over-Looked . . .
There are NO Commercially Available GoTo Mounts that are "Accurate Enough" to Track Stars without DRIFT ERRORS at Long Focal Lengths & Long Exposure Times. ( Without Guiding )

LONG Exposure / Super-Telephoto Focal Length Photographs REQUIRE Guided Mounts ( Optical Feedback of a Target Star's position & Corrections to the Mounts Positioning albeit Small Corrections for a VERY ACCURATE Mount but Needed Corrections None the Less )

What's my point ? / IF You want to be able to do a Large Range of Astro-Photography you will NEED a "Guiding System" as part of your "Mount Solution" . . . There's No Way Around this as far as I know.

This leads to the NEXT Question . . . How Accurate of Mount do I Need NOW that I'm Including a Guiding System to Correct Tracking Errors ? ( Excellent Question )

There is no Totally Simple Answer to this Question but the Research & Experience that put me personally on the iOptron Zeq25gt page confirms this mount ( for it's intended load rating ) is Adequate . . . It Tracks AMAZING Well - WHEN Properly Setup & It's NOT Super Expensive - Plus it's Relatively LIGHT WEIGHT !

If you are Yet to Purchase ANY Mount & Are Usually Located in a "Large City / Light Pollution Area" . . . You may find Greater Use from a solution like the New Pentax K3 ii with INCLUDES an Optical Star Tracking Solution complete with Built-In Compass & GPS & Optical Correction.
( This is a Limited Solution as far as MAX Focal Length ~500mm & MAX Exposure Time @ 5-Minutes ) but should get you Trained Up & Experienced Enough to determine the Next Level of your Astro Passion & Is HIGHLY Portable & Costs less than $1,000

https://www.flickr.com/search/?text=K3%20AstroTracer

swimswithtrout wrote:

Orion12 wrote:

I would NEVER tell someone that a "Good" Mount is not "Extremely Important" . . . I would add it's FUNDAMENTAL . . . Their is however a Precision Mount Aspect that is often Over-Looked . . .
There are NO Commercially Available GoTo Mounts that are "Accurate Enough" to Track Stars without DRIFT ERRORS at Long Focal Lengths & Long Exposure Times. ( Without Guiding )

LONG Exposure / Super-Telephoto Focal Length Photographs REQUIRE Guided Mounts ( Optical Feedback of a Target Star's position & Corrections to the Mounts Positioning albeit Small Corrections for a VERY ACCURATE Mount but Needed Corrections None the Less )

Completely untrue !!! You're just going to have to pay A LOT more, than what you pay for a ZEQ25, but there are plenty of mounts that will let you image, unguided, through a "long fl" OTA and the M zero is one of them ! The OP was thinking of using a 4-500mm lens and the M Zero is MORE than capable of shooting all night long at that fl without autoguiding.

You Seem to be Telling Me that a M Zero & Other Mounts ( Expensive Ones ) would take 10-Minute, 20-Minute or 30-Minute Exposures with a 500mm OTA / Un-Guided ?

I'd like to SEE CONFIRMATION of that !

SHOW ME PHOTO's of Un-Guided 30-Minute or 60-Minute Exposures WITHOUT Star-Trails @ 500mm or Above . . .

You actually SAID the "M Zero is MORE than capable of shooting all night long at that fl without autoguiding" . . .
So it's capable of 8-Hour to 12-Hour Exposures @ 500mm FL ? PROVE IT !

There are Numerous Solutions that will Take SHORTER Exposures ( 5-Minutes or Less ) @ 500mm and Don't Cost $4k for the Mount . . .

Here's a Video of the Zeq25gt that's SHOWING 2-tens of a PIXEL ( Sub-Pixel ) Tracking Accuracy with a Mount that Retails for less than $800 . . . It's using a LoadStar Guide Camera & Borg 250mm Guide Scope . . . And it WILL Track the Same Star ALL NIGHT LONG ( If Seeing Permits ) Total Mount Equipment Costs ~ $1,500.

https://www.youtube.com/watch?v=fs43HyOlk0c ( Actually WATCH this 2-minute Video )

Please Don't Respond with WORDS or OPINIONS or Some WIDE-ANGLE Photo . . . SHOW ME 20-Minute or 30-Minute Exposures @ 500mm or Better PROOF or Let It Go.

Now it is getting interesting...

Concerning costs and facts, if the above said is true and for me I think I have seen some assertions from users that claim that at least up to like 5 or 10 min it shall be possibleto do so without guiding. Anyway, maybe it comes down to this: what is the time without guiding for this or that focal lenghth...

swimswithtrout wrote:

Orion12 wrote:

I would NEVER tell someone that a "Good" Mount is not "Extremely Important" . . . I would add it's FUNDAMENTAL . . . Their is however a Precision Mount Aspect that is often Over-Looked . . .
There are NO Commercially Available GoTo Mounts that are "Accurate Enough" to Track Stars without DRIFT ERRORS at Long Focal Lengths & Long Exposure Times. ( Without Guiding )

LONG Exposure / Super-Telephoto Focal Length Photographs REQUIRE Guided Mounts ( Optical Feedback of a Target Star's position & Corrections to the Mounts Positioning albeit Small Corrections for a VERY ACCURATE Mount but Needed Corrections None the Less )

Completely untrue !!! You're just going to have to pay A LOT more, than what you pay for a ZEQ25, but there are plenty of mounts that will let you image, unguided, through a "long fl" OTA and the M zero is one of them ! The OP was thinking of using a 4-500mm lens and the M Zero is MORE than capable of shooting all night long at that fl without autoguiding.

I agree that it is much less expensive to buy a good, high quality mount equipped for auto guiding than to buy the absolute best mount that is capable of unguided exposures. But being capable of working unguided is different than actually producing an unguided exposure. To be successful will most assuredly require a permanently installed mount, where much time and effort has been expended in getting an absolute perfect polar alignment. Certainly this will be next to impossible with a portable setup. Here's where auto guiding helps. If polar alignment is close (but not perfect)  auto guiding can produce good images.

I'm assuming, SWTrout, that "shooting all night long" does not mean an 8-hour exposure, but means a series of much shorter exposures obtained over the course of an entire night. An all-night single exposure would, of course, be totally over exposed unless shooting at something like f/22. Certainly a series of shorter exposures obtained over the course of an entire night is what your comment intended. And I agree that if money was unlimited, one could acquire a mount capable of un-guided exposures. But why? Its best to just take the tried and true course. No sense in reinventing the wheel.

Another point worth mentioning is that the stars do not move across the sky at a uniform rate. Particularly as a star begins to approach the horizon, refraction produced by Earth's atmosphere will elevate a star above its geometrically correct position. An example of this is when the Sun appears to be setting on an ocean horizon. Geometrically the Sun has already moved entirely below the horizon at that time. But atmospheric refraction has caused the Sun's apparent  movement to lag behind a uniform rate, raising it above the horizon. Unless a mount has software implemented to correct for refraction, errors in tracking will result. Of course with auto guiding this is a non-issue.

Just my two cents.

elgol20 wrote:

Now it is getting interesting...

Concerning costs and facts, if the above said is true and for me I think I have seen some assertions from users that claim that at least up to like 5 or 10 min it shall be possibleto do so without guiding.

A Large Factor here is "How Accurate" is your initial Polar or Star Alignment ?

If this is OFF even a "Little Bit" then the Most Accurate Un-Guided Mount in World . . . Will NOT have Favorable Results.

Anyway, maybe it comes down to this: what is the time without guiding for this or that focal lenghth...

Good Assessment so far . . . Those are Really GOOD Questions . . .

How LONG of EXPOSURES and at WHAT Focal Lengths ?

IF You KNEW those Answers it would be Much Simpler in "Finding the Ideal Solution" . . .
BUT ( Virtually No One Knows these Answers Going In / Not as a Total Certainty )

For Example . . . What IF . . . You End-Up wanting to Shoot Close-Up Views of Jupiter or Saturn ?
Well in THAT CASE . . . You'll Be WANTING MORE than 1,200mm or Even MORE Than 2,000mm in Some Cases !
I don't believe ANYONE Here would suggest that ANY Un-Guided Mount would pull that off with Even 5-Minute Exposures . . . ( Chime Up IF You're Out There / I would appreciate Examples  )

So the Guided or Un-Guided Question will ALWAYS be addressed at Some Point . . .

There are a Number of GOOD Mounts Available . . . Costs verses Portability verses Tracking Accuracy are ALL Major Considerations imho . . .

In my location although I can ALWAYS get good Mount GPS Locks . . . It's more often than not that I CAN'T get a CLEAN Shot at Polaris ( Pole Star ) . . . And getting Other Star Alignments is not as Ideal as a GOOD Polar Alignment . . . In those cases "Guiding" is a Savoir as it will Track your Target Star ( Regardless / Assuming some form of reasonable alignment is achieved ).

RustierOne wrote:

swimswithtrout wrote:

Orion12 wrote:

I would NEVER tell someone that a "Good" Mount is not "Extremely Important" . . . I would add it's FUNDAMENTAL . . . Their is however a Precision Mount Aspect that is often Over-Looked . . .
There are NO Commercially Available GoTo Mounts that are "Accurate Enough" to Track Stars without DRIFT ERRORS at Long Focal Lengths & Long Exposure Times. ( Without Guiding )

LONG Exposure / Super-Telephoto Focal Length Photographs REQUIRE Guided Mounts ( Optical Feedback of a Target Star's position & Corrections to the Mounts Positioning albeit Small Corrections for a VERY ACCURATE Mount but Needed Corrections None the Less )

Completely untrue !!! You're just going to have to pay A LOT more, than what you pay for a ZEQ25, but there are plenty of mounts that will let you image, unguided, through a "long fl" OTA and the M zero is one of them ! The OP was thinking of using a 4-500mm lens and the M Zero is MORE than capable of shooting all night long at that fl without autoguiding.

I agree that it is much less expensive to buy a good, high quality mount equipped for auto guiding than to buy the absolute best mount that is capable of unguided exposures. But being capable of working unguided is different than actually producing an unguided exposure. To be successful will most assuredly require a permanently installed mount, where much time and effort has been expended in getting an absolute perfect polar alignment. Certainly this will be next to impossible with a portable setup. Here's where auto guiding helps. If polar alignment is close (but not perfect) auto guiding can produce good images.

I'll second that . . . Getting a "Dead Nuts" Polar Alignment can be a Monumental Achievement that's not always "Easy" to duplicate . . . And IF it's NOT Achieved "Every Time" THEN the Accuracy of the Mount is of SECONDARY importance & the Strength of "Guiding" starts to Shine.

Should Note also that Guiding in Itself is Not a Fix All & Itself Requires a Good Mount as a Foundation to work properly . . . But is "MAGICAL" when properly implemented.

I'm assuming, SWTrout, that "shooting all night long" does not mean an 8-hour exposure, but means a series of much shorter exposures obtained over the course of an entire night. An all-night single exposure would, of course, be totally over exposed unless shooting at something like f/22. Certainly a series of shorter exposures obtained over the course of an entire night is what your comment intended. And I agree that if money was unlimited, one could acquire a mount capable of un-guided exposures. But why? Its best to just take the tried and true course. No sense in reinventing the wheel.

Another point worth mentioning is that the stars do not move across the sky at a uniform rate. Particularly as a star begins to approach the horizon, refraction produced by Earth's atmosphere will elevate a star above its geometrically correct position. An example of this is when the Sun appears to be setting on an ocean horizon. Geometrically the Sun has already moved entirely below the horizon at that time. But atmospheric refraction has caused the Sun's apparent movement to lag behind a uniform rate, raising it above the horizon. Unless a mount has software implemented to correct for refraction, errors in tracking will result. Of course with auto guiding this is a non-issue.

Just my two cents.

-- hide signature --

Best Regards,
Russ

That's a pretty valuable "Two Cents" Russ . . . Thanks for Your Input & Considerations . . .