Advice for an Astro Photography Setup [ THE MOUNT ] -Choosing a GEM mount for a 14 to 18lb Newtonian for photometric astrophoto

Sat, 07/18/2020 - 16:51

This is a branch of another post which makes an intro about my project and needs:


I am about to visit USA and I want to bring a telescope kit for making some photometric science, WITH BEST QUALITY / PRICE RATIO


 IMPORTANT: bounce.gif

In this post, I will  mark the questions I WOULD like to be answered with this emoticon enlightened and italics, to make a little easier to identify my questions .. Of course, you are invited in all comments you like,but this are the questions I would made if this were a conversation.


  • Stellar astro photometry /astrophotography of Variable Stars, Supernovae, and Near Objects (NEO) asteroids, and other pinpoint objects
  • Astrometry or measurement of  position, of asteroids , NEOs, 
  • Occultation observation of stars by asteroids
  • Observations of far - faint comets
  • Other transient events
  • Precise photometry of exoplanet transits
  • Measurement of orbits of faint moons of outer system planets
  • Measurement of proper motion of fast moving stars
  • Parallax experiments

IMPORTANT! WHAT ARE NOT MY GOALS! .... (but I can do very rare if the gear allow to, btw)

  • Color artistic photography
  • Nebula photography
  • Direct observation by a viewfinder
  • Planetary
  • Solar
  • Near big comets

I want to make astro photography with photometry with a IMX178 based camera like the QHY 178M Monochrome Astronomy Camera # QHY178M, the ZWO ASI178MM or an Orion StarShoot G4 Monochrome

Is a small 1/1.8″ sensor with 2.4um pixels and very sensitive.

My mount will be a weight light reflector of 8" like the aluminium tube

My favourite choice is the STEEL GSO 8" F5 which is 22lbs with all accesories (https://agenaastro.c...lector-ota.html( but will need a heavy mount, if I choose GSO I think I will have to choose the 6" version which is around 16lbs.


sct.png CHOOSING A GEM MOUNT sct.png


SIDENOTE: Size + weight


My Loving mounts in the price range we have are the following

Sky Watcher EQM-35 Equatorial Go To Mount # S30500 

PROS: UNEXPENSIVE BUt good enough for not-heavy payloads. Is very beautiful, and not quite heavy. Good brand. Polar scope. Stepper motor(I think is better , what do you think? enlightened) . I think Robert Spellman has one... see above the photos of their setups... and He works fine with it (I think with a 6" f4 GSO). Also have a nice feature to mount a DSLR with an objective to make wide angle photo... and satellites photos (I do that)...

CONS: Above 15-17LBS will work not very well in astrophoto. It is difficult find a 8" OTA for this mount. Except the Celestron SC mentioned above ( C8-A XLT 8" f/10 SCT that is about 14lbs). Is not a very sturdy mount. But Is the less expensive GOOD option I think. Does it have an after sale good and warranty support, I have no references?enlightened
What do you think about my pros and consenlightened
Can you suggest me an 8" telescope suitable for this mount in my budgetenlightened

iOptron CEM25P Equatorial Mount with 1.5" Tripod - 7100P
PROS:I love the very weightlight design and the management of the gravity center. Is a very nice design, and it sells in a very compact box or a nice (more cost) aluminium hard case. Is very precise and have a very nice precision gear.Less than +/- 10 arc seconds periodic error, GPS, very good polar scope. It is quite compact!!! to transport it.
CONS: More expensive but not impressive payload cappacity. I will be in the limit with most of the OTAs. It is a very fragile mount, you can broke if you dont manage properly. It is a very picky gear and there are cases of damage in the gears if you did not a very good equilibrium in the setup. Does it have an after sale good and warranty support, I have no references?enlightened
What do you think about my pros and cons enlightened

Celestron Advanced VX Mount with Dual Saddle Plate # 91519 
Celestron Advanced VX 8" Newtonian Telescope # 32062

PROS: Good brand, I hope a good aftersale support, am I right? enlightenedIf I but the kit with the 8" OTA I will have a perfect fit between the different parts. Also includes the eyefinder, the power connector, and the DC power cable... I think doesnt include the AC cable, are you sure? .  This mount HAS VERY GOOD REFERENCES for beginner astrophotography. And very good objective data in much performance annalisys . It has a lot of users, and a lot of opinion in the internet. Its one of the basic mounts. and can hold HEAVIER telecopes if y want to upgrade in a future... Also this mount avoid the meridian flip
CONS: The boxes where they ship this are HUGEundecided.gif , and the mount is very HEAVY . Perhaps is the best option, but if I cannot handle by myself in the transport from tecate/san diego to the tijuana airport. Im in a BIG problembawling.gif . Ive watched carefully the unboxing of this mount and the kit. IT DOESN INCLUDE the polar finder.

Did I say this boxes are  F K N G LARGE + HEAVY???? 
What do you think about this mount and my thoughts?enlightened



I prefer the Sky Watcher EQM-35 but I've watched other options

Explore Scientific EXOS-2GT Computerized Mount with PMC-8 GoTo Electronics - Black - ES-EXOS2GTPMCT3-00


It seems a budget one, but specs say it can hold heavier scopes than the EQM-35. Not very popular. But If i need a budget option for a 8" tube. is this an option?enlightened

Orion Sirius EQ-G Go-To German Equatorial Mount - 09995

IS a good reference, and a very good mount for entry level. But it is more expensive. Is an option if budget works...

Of course around 1000-1200USD mounts are a lot of very good options , like ieq30pro, HEQ5, CEM40, CGEM (But I think they are clearly over budget!!!!! .... what do you think about this "other alternatives"enlightened

jump.gif What do you think specifically about the Meade LX85 alternative?enlightened



I like very much two telescopes built by an amateur astronomer : Robert spellmanbow.gif , take a look. He takes wonderful B&W photos with this gear: 

It is a 150mm Astrograph f4 with the ORION STARSHOOT G4 and a Skywatcher EQM35-Pro

Thank very much for your advice


This is a branch of another post which makes an intro about my project and needs: