Yes, I am trying to figure out if I only want to make videos of Solar-System objects (such as for stacking, or filming eclipses/transits/occultations), do I really need a GOTO mount? It seems like just any German equatorial then should be able to keep up with Solar-System objects, only requiring minor adjustments, even without a clockdrive? What about at a really long focal length length with a narrow field of view (such as a Maksutov-Cassegrain OTA) for planetary imaging? Would their motion still be close enough to the sidereal rate using a one-axis clockdrive? What are the advantages of a two-axis clockdrive? I suppose you cannot adjust for declination if there a clockdrive running on the ascension axis, unless you have a second motor?
Would I still need GOTO for the 2019 Mercury transit though? Mercury and Sol probably have the most deviation I would imagine? The transit lasts for about 6 hours.
You can make those videos without a goto mount. Although any GEM can "keep up with solar system objects with minor adjustments" without a clock drive, you get two big advantages by using one. Keeping up or tracking will be easier and more accurate with a clock drive. Easy is a good thing and more accurate tracking means that your images will be better.
Be careful with really long focal lengths. Longer focal lengths increase the requirements for mount stability and tracking accuracy.
Transits and eclipses are FUN! I have a suggestion. Practice!
A short tube refractor would be an inexpensive way to start and learn how everything works together. If you use an aperture under 100mm your mounting requirements will decrease while portability increases. Believe it or not, you don't need much focal length to get good pictures of the Sun.
How much do plan to spend? Will you fly to your Mercury transit observation site? Next year I hope to go to Chile for the total solar eclipse. My telescopes, mounts, and camera equipment will need to travel with me. Prior eclipse and transit trips included a 70mm refractor and one-axis driven GEM. When I flew to observe and photograph the 2012 Transit of Venus the telescope was carry-on luggage and the mount traveled down below. Last summer when we drove to Oregon for the total solar eclipse, I took the 70mm refractor, a 100mm refractor and the driven GEM as well as another manual altazimuth mount for visual observations.
Goto is not required to observe or photograph an eclipse or transit. In fact, goto is probably not much of an advantage for those activities. Even though the transit of Mercury lasts several hours your exposures will be quite short. Clock driven tracking is a different matter. Although I enjoy observing an eclipse or transit with a manual altazimuth or GEM mount sharing the experience with others is more challenging. Challenges and complications during an eclipse or transit are distracting and detract from the experience.
That said, goto can enhance your experience while observing. My next mount will be a goto mount. I have been looking at the Celestron AVX and the new Meade LX85. The combination of a decent weight payload and high portability interest me. Although I will eventually end up with something like a Losmandy GM811G those two smaller mounts seem better for my current plans.
Here is my nagging question. Should I take a goto GEM and 100mm refractor to Chile or trim my traveling astronomy kit for this trip? My current driven GEM is just as bulky as a goto mount but makes taking pictures easy compared to my manual altazimuth mount. I could take the 70mm refractor but it was really nice to have both scopes in Oregon. (observing/photography)
Practice Nicole. If you purchase a decent mount and a simple telescope you can determine what works for you. Add a solar filter and camera to your kit and soon you will be advising others on solar system photography.
Edited by Celerondon, 23 June 2018 - 07:09 AM.