Date
1 - 9 of 9
Pier height selection help needed...
|
jeff_crilly <ne14mx@...>
Last time for me, I promise. (Btw, I've been thinking of compiling
some dimensions, i.e. eyepiece-height-@-zenith-from-pier-top for various OTAs on the AP1200 and AP900.) I'm trying to finalize the AP1200 pier hieght. Either 42" or 48" is appropos for me -- the downside w/ 48 is that the saddle might be too high to easily get a 30 lb OTA up there. Otoh, if 42" is too short, I'll be crawling on the ground at zenith. I did a bit of estimating, and some math... Zenith is the worst case, so assuming the DEC is horizontal, the center of the DEC shaft looks to me to be about 10" from the TOP of the pier. (I assumed the diameter of the DEC top to be about 7".) With a 12" SCT, the back of the SCT (including diagonal) is probably 8" from the center of the DEC axis. (assuming tail heavy SCT.) This puts the eyepiece about 2" ABOVE the pier height. So eyepiece height w/ the 12" SCT for 10x42 and 10x48 is around... 42" pier: eyepeice 40 inches above the ground. 48" pier: eyepiece 46 inches above the ground. Seated comfortably (knees at 90 degrees), I find that 40" requires the neck to be bent just a little. (I'm 5'9") So, I suspect the 42" pier will work w/ the AP1200, and an SCT, visually. However, a refractor (right now FSQ) is going to have an eyepiece height way too low on the 42" pier. (Fwiw, I use the FSQ on an AP900 w/ a 48" pier and it is ok.) Its really a tossup for me.. the 42" has the advantage of being lower when loading the AP1200 and OTA on it, at the expense of being a tad bit too low for viewing at the zenith, which is fairly rare. Anyone have direct experience? Am I missing something? thanks jeff |
|
|
|
Hank Sielski
Jeff,
toggle quoted message
Show quoted text
My situation is a bit different than yours (I'm 6'4 and have an AP155 F/7 and am happy I went with the 54" pier for my 900), however, I think that you could probably have the "best of both worlds" if you mount your FSQ on top of your SCT and got the 42" pier. I would think that even your 900 could handle this weight, at least visually, so the 1200 wouldn't even be breathing hard, and the FSQ would be at a better height. Otherwise, keep the 900 and the 48" for your FSQ On the other hand, if you're after a much bigger refractor in the future, then even 48" might be too low... Good luck. Hank On 5/26/06, jeff_crilly <ne14mx@...> wrote:
|
|
|
|
Jeff Young <jey@...>
Jeff --
toggle quoted message
Show quoted text
I use a 40" pier with a 16" SCT (on a 1200). It's a bit too low for comfort (but my dome wasn't high enough to go any taller). I'd say 44" would have been ideal for me with just the SCT. I have an FC-100 riding piggyback though, which can be pretty high up when viewing lower targets in the northern sky; 42" might be a better compromise with a piggyback. In your case, your eyepiece will hang down from the dec axis less, so lower wouldn't be quite as uncomfortable. But a piggyback refractor would be sitting on a smaller OTA, so going a bit higher wouldn't be as much of an issue. But higher also has other issues. My pier is bolted to a 24" concrete post about 12" below floor level (so it has a total length of 52"). My previous pier was 32" overall, constructed of the same material (1/4" walled 10" nominal steel pipe). The shorter pier had markedly better dampening time (less than 1/2 second as opposed to about 1.5 seconds). So all things considered, I'd go with 42". -- Jeff. -----Original Message----- |
|
|
|
Mal Speer <mal@...>
I have an AP900/C14 on an ATS 42" Pier. I think that 42" is a good
compromise. When looking at the zenith it is pretty low, but not impossible to view in my Tele Vue observing chair. On the other hand when looking at something near the horizon, it is a little high so I turn the diagonal down and that works OK. Just make sure that your eyepiece is locked down. By the way I am about 5'10". I have a 1200 coming in soon and I ordered an ATS 42" pier for that also. Mal --- In ap-gto@..., "jeff_crilly" <ne14mx@...> wrote: is appropos for me -- the downside w/ 48 is that the saddle might betoo high to easily get a 30 lb OTA up there. Otoh, if 42" is tooshort, I'll be crawling on the ground at zenith.probably 8" from the center of the DEC axis. (assuming tail heavy SCT.)the neck to be bent just a little. (I'm 5'9")visually. AP900 w/ a 48" pier and it is ok.)lower when loading the AP1200 and OTA on it, at the expense of being atad bit too low for viewing at the zenith, which is fairly rare. |
|
|
|
mogulskier_groups
Hi Jeff,
Wouldn't you be using a diagonal when using it with an eyepiece? That's my only input :-) Dave --- In ap-gto@..., "jeff_crilly" <ne14mx@...> wrote: is appropos for me -- the downside w/ 48 is that the saddle might betoo high to easily get a 30 lb OTA up there. Otoh, if 42" is tooshort, I'll be crawling on the ground at zenith.probably 8" from the center of the DEC axis. (assuming tail heavy SCT.)the neck to be bent just a little. (I'm 5'9")visually. AP900 w/ a 48" pier and it is ok.)lower when loading the AP1200 and OTA on it, at the expense of being atad bit too low for viewing at the zenith, which is fairly rare. |
|
|
|
Mike Chapa <mjchapa@...>
Hi Jeff,I would go with the 48". I have the 24" on JMI wheely bars and am literally on the ground at zenith with a 6" f7 refractor and a diagonal... Mike Chapa http://www.chapaccd.com |
|
|
|
ayiomamitis
--- In ap-gto@..., "Mike Chapa" <mjchapa@...> wrote:
I ordered the 54" pier and hopefully will be able to provide feedbackHi Jeff,I would go with the 48". I have the 24" on JMI wheely bars and am and experience shortly upon the arrival of the new AP1200GTO which will gracefully host my baby (AP160). Anthony.
|
|
|
|
Edd Weninger
I've never seen a picture of Anthony, so I don't know what he looks
toggle quoted message
Show quoted text
like. but I can sure see him smiling ear-to-ear. Edd Weninger (AP1200/AP155 on 46" pier, slightly too low) --- In ap-gto@..., "ayiomamitis" <ayiomami@...> wrote:
|
|
|
|
ayiomamitis
Edd,
toggle quoted message
Show quoted text
There is a semi permasmile on my face thanks to the arrival of the AP160 and which is about to become a permanent permasmile with the arrival of the AP1200GTO. Oh how many times I have pulled my hair thanks to the "guiding" of my Losmandy G-11 and/or the number of exposures tossed out thanks to the countless little ovals which were supposed to be stars. Even with my AP160 at 1200 mm focal length, I cannot go unguided past 20-25 seconds. With my Pronto (450 mm focal length), I am lucky if I can get 2 minutes exposures binned 2x2 on my ST2000XM. If only I could find the words to describe my anxiety for the arrival of the AP1200GTO. I had a similar problem with first light of my AP160 last May ... BREATHTAKING. These toys (AP160, AP1200GTO) should be outlawed ... they are "deadly" weapons and tools! Anthony. --- In ap-gto@..., "eddwen2001" <Eddwen@...> wrote:
|
|
|