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theskyisthelimit99

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About theskyisthelimit99

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    Nebula

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    Pittsburgh, PA
  1. This is my first GEM, the cem120. I've literally just unboxed it and set the latitude. I was given the stat from ioptron for 40.5 lat. that its about 9.40 in height from the mount plate to "center of OTA". Now i'm trying to confirm this. I'm not sure what position that stat comes from, is it the "parked" position, zero position, counter weight straight out (not aimed down) one? What i'm wondering, is if i change telescopes (from 8se) to say edge 11 or even 8se with a piggyback refractor, that height is still considered 9.40 to center, but center of where exactly. How do I target a 53" wall height (and adjust my pier that i'm creating, concrete in the process)? If adding piggy backed equipment really has no barring on that wall height position, then I guess i can just go with 53-9.40 to get the pier height I need to make and not worry about things being too high? Thanks in advance for any clarification
  2. Yeah will do sorry i usually do that. And i have actually modified plans slightly, dropping back to 10" pvc and the double plate option, lower plate to jbolts and lower plate connecting to upper via m10 bolts and the upper being the connection to the telescope mount, most likely 4" from the pier top to the mounting area at the top.
  3. I checked around on just having the cement delivered, the best i can find is $280 for a 1 yard minimum (should be just under 1 yard), which isnt a bad price being as i'd pay around $220 for lowes to deliver everything inclusive of a mixer rental. So ill probably do this option, but i imagine i just wheel barrow it from the street, so they probably wont help.
  4. I have a cem120 inbound, and in the preplanning phases for a concrete 12" wide pier (inside of pvc for the form). I'm at latitude 40.5, so i think the CW's will clear the 12" (i think) The issue is the template for the mounting plate at 8.25x8.25 and 11.67" diag. puts the j bolts or anchors too close to the edge of the concrete. (1.5ish) (also unsure how i go about printing a scaled photo of this to use as a template) So my thought process has me bolting together two 3/8" a36 steel plates off ebay and putting the jbolts closer to center (via threaded/tapped holes though) and tapping holes in the top mounting plate for the mount. I'm assuming a36 steel (like this off ebay) is ok to use and 3/8" seemed thick enough though maybe 1/2" to be safe. My jrods i'm shooting for will be 5/8" across or 3/4" and maybe 13" long (rebar in the tube etc down to 4 feet below grade). I know there a few 120 users that have custom made a piece that can basically extend the pier to avoid this, but i'm having trouble finding local fabricating shops that do this or do it economically (steel city you would think more do). At first i hunted for aluminum options for plates (3/4" thick) and most for two 12" ones are $150-$270 Has anyone gone through this with a cement pier and multiple or single plates and found a solution for the cem120? Thanks in advance
  5. Any concerns with vibrations with the metal pier route? Either way quite a few bags still needed for an 18 to 24 square footer
  6. Yep I was considering the steel pier option because I may move one day. I'm trying to save coin though so probably sticking with concrete if I can figure out where to get material for the pier adapter that will be above the 12 inch round concrete pier
  7. Well i was able to find the hole pattern and the rough estimate on the height of the cem120, i'm definitely on the cem120 bandwagon, but i should probably get my pier created (10-12" sonotube) prior to ordering so i have a way to get it connected and tested (or after the nexdome arrives)
  8. Back to the ap900 possibility, I did find out that the one in question is from the year 2000, he claims never an issue with it, no noises or anything along those lines, however he's never greased it or had to. I dont think the price was flexible, if it were it might be a consideration, though the age concerns me. Does anyone know how long these can last (for that one its already at 19 years)?
  9. Look i'm sure these are isolated instances, however if you dig around you will find plenty of discussion on these and the issues "some" have had, its not gossip, unless they are making up stories or dont know what they are dealing with. I know someone first hand that went through several cem60's before they had one that worked and from another forum someone directly i spoke to that went through three of the cem120's. I also have talked with folks that have the 120 and no issues and love it. Take it with a grain a salt here. No one is trying to spread gossip here, but merely trying not to end up with a $4000 brick or go through the pain of repeated swaps if thats really what it takes to get a good one.
  10. Ok, i think that makes sense to me at least. Yeah then im guessing going for the ap900 probably wont benefit me, at least not in the medium term. The ap900 in question is around 6500 (vs 4k for the cem120 new). The person says its a cp2 upgraded to cp4, gave me the serial number as well. Comes with the cp4 controller, hc, cw shaft and 20lb weights, 18lb and 10lb weights and another 7lb one. Has the saddle and polar scope too along with the software licenses.. not real sure on the age, comes with a custom grease kit to regrease. I guess on paper it sounds good, the seller is reputable. I could probably still do just as well going hdx110 i would imagine if not the cem120
  11. What about differences in PE, ie: one rated at say 5 arcsec/pixel (i forget the data point) vs another like the cem120 at say 0.15.. how critical should i be in comparing those stats.. ie: for someone like me doing minor astrophotography or even mid duration subs 5-10 min, would such figures make much difference in the final images.. i dont understand these stats so i'm not real clear if there is an advantage.. ie: cem120EC vs even an ap900 used, let alone cem120 vs cem120ec
  12. Would a used ap900 with cp4 be considered a much better idea than even a cem120 here? Im still a bit leary of going used especially if its older, but its my understanding that the update to cp4 can occur even on older setups. Anything to ask or look for in this type of situation?
  13. Thanks for the link, yeah i'm in the usa, i would have considered it, though primarily looking for the 11 edge (though i probably should entertain some larger meade f8 scopes, another story).
  14. I've decided i'm going big or going home on the mount, simply because i dont want to change things later on and more payload capacity the better (going on permanent pier, in nexdome, long term goal full automation) I'm wondering of these choices or maybe another i havent considered, which would give me the least headache or tinkering needed. Which would do well with really long exposures (above 5 min?), though with a hyperstar most are 60 seconds, but if i later piggy back or side by side a larger refractor that could mean longer exposures there. I dont intend to swap equipment in and out, i will probably be quite happy just doing hyperstar on this setup and planets and maybe some imaging without hyperstar at f7 for many years (given that SW PA weather sucks and we are lucky to get 40-50 good nights per year i think). UPDATE: i've decided to go for the cem120, 10" pier and double plate system as of now. So that said.. (originally i figured a cem60 would just make the cut at 45 lbs but i want growth and not to have to change things or create issues) I guess a used (if safe to get used), ap900 (cp3?) would also be viable. On the 120.. I've seen some reports of some issues with the cem120, often the RA worm needing changed i think? And other issues with stars being elongated, though i'm not sure if its directly related to the 120 mount itself, ie: this thread though most of it is beyond my current understanding. Also, going to the ec version of the 120, well beyond my price gap, just curious if any real benefits for what ill be doing, which honestly will probably be short subs and maybe guiding later (i've read that if you ad guiding later its probably just as effective?). I'm not sure its worth a 1500 price jump though, for my current needs anyway. Any suggestions Thanks in advance Here are some estimated weights i had figured (option b was drop back to a 9.25 to save some weight, but for planetary i really wanted that extra light power): C11 setup with just hyperstar and maybe guiding (though not needed i dont think except for maybe planetary): C11: 28lbs 9x50 finder: 1.5 3x barlow: 0.36 guide scope: 5 ccd for planetary: 1.5 (worst case) Celestron focuser: 1.5 i think Weight of dovetail? ? missing things?: ?? filter wheel: 1.1lbs Total: 40-42? C11 with other options with side by side (likely wouldnt get to this for a long time): c11 28lbs 9x50 finder: 1.5 3x barlow : 0.36 guide scope 5 ccd planetary : 1.5 celestron focuser: 1.5 dovetail and other side by side adapters: 10 piggy back mount or side by side mount?: 2 apo scope 120mm: 15? apo guide scope on apo: 5 apo camera worst case: 3lbs filter wheel: 1.1 apo focuser(electronic): 2-6? misc adapters to fit Could be 81lbs here, i could see 60 eventually maybe (unlikely i'd ever have this complex of a setup)
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