Sitting at a large telescope in the field

[Ivan Maly]

What do you sit on at a remote dark site when looking through a large (say, 22" and up) telescope pointed high? My adjustable chair goes to ~40" (1 m), and it is enough to observe near the zenith with my low-profile f/4.5 16". Since for me this height means that one foot can remain on the ground, stability is acceptable. However I imagine that a ladder contraption on which one can sit to observe with a large scope near the zenith and which is acceptably stable on not exactly even, grassy, or snow-covered ground may easily become the least transportable part of the whole setup! After all, what we are talking about here, for serious visual observing, is a mounting for a 200-lb detector (a 100-kg "camera"), albeit for short subexposures ;) Large telescopes I've seen required standing when the target was high, even in an observatory - and the question I have is about a transportable solution.

[Howard B]

Hi Ivan,

You're right, an adjustable seat-ladder big enough to use with 22 inch and larger scopes would be quite the contraption and not very transportable. That's probably why people either use a ladder or use scopes that don't require a ladder. I can also imagine that a tall ladder-seat would be tricky, if not downright dangerous, getting into an out of the seat.

That said, the 90 inch Bok telescope on Kitt Peak has a dandy observing platform that rises up and down and a little side to side. It has a hand rail on one side, if I remember correctly, a small table for notes and a simple but comfortable chair. The platform is about 5 meters square and can go up about 5 feet or so above the observatory floor, and even this is fairly dangerous. A few years ago one member of the group I was part of fell off the platform in the dark and broke her wrist!

[Demiles]

What do you sit on at a remote dark site when looking through a large (say, 22" and up) telescope pointed high? My adjustable chair goes to ~40" (1 m), and it is enough to observe near the zenith with my low-profile f/4.5 16". Since for me this height means that one foot can remain on the ground, stability is acceptable. However I imagine that a ladder contraption on which one can sit to observe with a large scope near the zenith and which is acceptably stable on not exactly even, grassy, or snow-covered ground may easily become the least transportable part of the whole setup! After all, what we are talking about here, for serious visual observing, is a mounting for a 200-lb detector (a 100-kg "camera"), albeit for short subexposures ;) Large telescopes I've seen required standing when the target was high, even in an observatory - and the question I have is about a transportable solution.

This is a very timely question since I've been researching this very issue. I use a 15in. F4.5 on a EQ platform, my current observing chair has a maximum useable height of 30 inches. This means I'm only sitting while observing objects at maybe 55 degrees or less. Above that it becomes just something to hold on to to stabilize myself while looking in the eyepiece. I've been eyeing up a Cats Perch or one of Walts observing chairs to get me higher.

[akarsh]

I just stand. I sit down and give my legs some rest when I'm writing my observing log, looking through my observing list, or trying to figure out how to star-hop etc.

I enjoyed the comfort of sitting down and observing with my 6" at TSP, and it felt really nice, but in my equation, you either get the large aperture or the comfort. It would be nice if you could have both...

[Ivan Maly]

Thank you for the pointers, gentlemen. I should add that the "acceptable" stability of my old steel chair means that I have only fallen a couple times from it over the years, and, thanks to the same grass or snow that makes it unstable, softly. The tallest Cat's Perch and Walts, being a foot taller and having a similar footprint, don't look good to me. The observer demonstrating the former has a paved area - good for him!

[Ivan Maly]

...but in my equation, you either get the large aperture or the comfort. It would be nice if you could have both...

My experience with larger apertures is limited but from what I can tell this trade-off is a big factor contributing to their diminishing returns. If I ever go bigger I still intend to sit. The reason I am asking these questions now is that it appears that there are eminently transportable telescope designs that don't require a truck, van, or trailer, but a stable ladder suitable for seating when looking at the best part of the sky (overhead) will call for such a vehicle.

[Ciel Extreme]

Hey Ivan

I'm with “akarsh” on this one... recent news reports about the Western propensity for sitting for large parts of the day contributing to increased risk of cancer and heart disease has me thinking that I don’t want my favourite hobby contributing to my demise. Sitting works well with refractors and SCTs, where the observer is behind the telescope and the eyepiece, using a star diagonal, can easily be rotated to a comfortable viewing position. But with reflectors.... I stand for 90% of my observing sessions. I will occasionally use a chair if I am observing objects that are lower than about 45-50 degrees above the horizon. Objects that are “deep south” from my location (for instance in Scorpius or Sagittarius) I use a technique I call “grovelling” which requires me to get down on my hands and knees to get at the telescope eyepiece. While there praying, I often ask myself how I ever ended up in this hobby, especially as the knees of my trousers soak up the dewy ground! When observing with chairs I find myself shifting the chair several times during the course of an observing session as I try to avoid the eyepiece putting a serious dent in my eye socket. When I’ve used ladders with larger telescopes (e.g.: 25-inch f/5s), I can't count the number of times I’ve had to shift the ladder during the session, either to keep tracking the object or to shift to another part of the sky. The freedom of having your feet firmly planted to the ground with a mid-sized Dob (like my current 18-inch f/4.5) cannot be overstated. So easy to adjust as I follow an object across the sky or move on to something else. If I got a larger Dob down the road, the first thing that goes overboard is focal ratio. If I upgraded to, say, a 22-inch, I'd go with an f/4. 25-inch... hello f/3.5! While sitting undeniably contributes positively to remaining relaxed while observing, the negatives of shifting a ladder around (especially on grass) outweigh that consideration in my opinion.

[Ivan Maly]

Thank you for sharing your experience and advice, Mark.

Deviating a little from observing high overhead, when looking at southern objects from here (and the object had better be good, e.g. M83 - sketch link (http://1.bp.blogspot.com/-cQL31ZH5c8E/U4TVBMV0L4I/AAAAAAAABFY/w-ptd_qkR3Q/s1600/M83+2012+IVM+2.jpg)) I sit on the ground on plastic tarp. When particularly low, I lie almost in the Ancient Roman manner, if not on an elbow then on an outstretched arm. And on the topic of eyepiece punching you in the eye, I define a windy night of observing with a Dobsonian as the Dobsonian punching you in the eye, but a windy night of observing with a massive SCT as your being thrown off the chair and onto the eyepiece ;)

[Jim Chandler]

You guys. Don't fear the ladder. The ladder is your friend. You don't stand on the ladder; you drape yourself onto the ladder. It provides a rock solid viewing platform. Sitting's not bad, but standing? The worst. Inherently shaky. The human body's not designed to remain motionless while standing. I detest southerly objects that transit too high to sit but too low to get on the ladder. A good ladder* is the best.

* "Good ladder" is defined as a tripod ladder with 6-8" rung spacing. Four legged ladders with 12" rung spacing are for painters, not astronomers.

[Ivan Maly]

Thanks, Jim. Is the good ladder as tall as the telescope? How wide?

[Jim Chandler]

Thanks, Jim. Is the good ladder as tall as the telescope? How wide?

Rough rule of thumb: Eyepiece height at zenith minus two feet = ladder height. For example, Ana is 5'2" and she uses an 8' ladder with the 25" f/5.
Tripod ladders are wider at the bottom than at the top, sort of like having built in outriggers for lateral stability.

[reiner]

Hi Ivan,

I sit most of the time at my 22". It's a lowrider and f/4, so eyepiece height is quite low at around 160 cm at zenith. The seat I am using is this one

http://www.reinervogel.net/sonst/Sitz/Beobachtungsstuhl1.jpg

It can be adjusted high enough to allow being seated in most observing situations.

[Ivan Maly]

Thank you very much, gentlemen, great information.

Reiner, I looked at your website again and am beginning to really appreciate the tilted-secondary Newtonian design in this context!

[Dragan]

You guys. Don't fear the ladder. The ladder is your friend. You don't stand on the ladder; you drape yourself onto the ladder. It provides a rock solid viewing platform. Sitting's not bad, but standing? The worst. Inherently shaky. The human body's not designed to remain motionless while standing. I detest southerly objects that transit too high to sit but too low to get on the ladder. A good ladder* is the best.

* "Good ladder" is defined as a tripod ladder with 6-8" rung spacing. Four legged ladders with 12" rung spacing are for painters, not astronomers.

Jim beat me to it. The ladder IS your friend.

I don't quite get the aversion to ladders we're seeing in astronomy of late, not that you're voicing that opinion Ivan. I'm speaking in general. It isn't like you're painting a ceiling or changing a light bulb in the dark. You use the ladder for support. As long as the feet are sure footed, its quite a comfortable and safe way to observe. I personally like to hook an arm through the rungs and then lean on my ladder while at the eyepiece. I have found this to be the most comfortable position for observing and wouldn't change it. "Draping" yourself as Jim mentioned is a perfect analogy. That's what you do.

And as Jim mentioned, be sure to have the proper spacing. Standard 12" run spacing is EXTREMELY uncomfortable. It'll guarantee you that the object you want to look at will be just a hair to high that you'll have to stretch or just a bit too low that you'll have to crouch. Both suck and quickly make a night of observing miserable. I use an 8' fiberglass ladder with 12" rungs BUT I've added half-steps at 6" increments. Now, I never have to worry about height.

[Ivan Maly]

Thank you, Dragan. This method sounds great.

[javier_gl]

Hi all

I have a very simple and easy to made solution for sitting at a large telescope: the chair-ladder :D

You have only to screw a small wood plate on the top of the ladder's up arm, as you can see in the images below (me, my chair-ladder and my 24"). Of course it has not adjusted height, but it's comfortable enough when the telescope aims 70º and up.
13231324

With a smaller chair-ladder, I use the same method in a 18" telescope:

13251326

[Ivan Maly]

Thanks, Javier. Great photos.

[FaintFuzzies]

Funny how the title said "largest" telescope. There were several times in the last two years I had the smallest scope of the field with my 22" reflector.

[Bob Douglas]

A most interesting discussion. I have spent time thinking about how to arrange to sit while observing with my 28" f/3.6 Starstructure. And I failed to come up with anything that is workable. But let me suggest something that no one has suggested and that I am using. First, I am in the "the ladder is your friend" group. But I actually use two ladders. Wait, don't laugh or smirk. While this is not for everyone, it can be the best choice for some. I have an 11 lb 6' Polter ladder whose rungs are 7", 16", 25" and 34" above the ground. I also have an 19 lb 6' Cosco ladder whose rungs are 11', 22", and 34" above the ground. Both ladders are light, especially the lighter one. There are two advantages of this system over using one Orchard ladder. First, it is almost guaranteed that if you are looking at an object using one ladder and have to stoop down or stand on your toes to look straight through the eyepiece, if you switch to the other ladder you will be looking straight through the eyepiece while standing straight. This is important for me. [You can see that the effective successive distances between adjacent rungs, from bottom to top, are 4", 5", 6", 3", & 9".] The second advantage is that I frequently have the second ladder next to the first ladder, on which I standing. This allows me to put eyepieces and the remote controller on a "shelf" on the second ladder. Now you might be thinking "and I'm going to have to transport two ladders"! Well yes. But in my case I use a small trailer to transport the scope, and the heavier ladder is placed against one wall of the trailer, bungeed corded to the side of the trailer (using ringlets build into the trailer's wall), with the lighter ladder on top of the heavier one, and also bungeed corded to the wall. The second ladder causes no problems whatsoever. I admit that an Orchard ladder is more stable than the ladders I use and, with the rungs no more than 6" apart, is a good solution. But my ladders give me enough stability and the two advantages that I mentioned I believe are significant. But if you transport your scope in a car or a van, ie no truck or trailer, then handling two ladders may not be your cup of tea. But there may some who will find my method useful.