ribuck

Thanks all,

I feel a lot happier about the construction method now. I think i'll go with some 8" plastic and have it set in the ground with holes in the pipe at the bottom.

Now to try and figure out how many bags of sand, stone and cement i need to fill a 8" pier

Rich.

I'm more confused than ever, Gina's post say to have the pipe above ground, yet waynes post of his build clearly has the pipe in the ground ?

Anyone else got any views on this please on pipe in or out of the ground ?

wow, that's a lot of bags of cement and stone to mix......... :-(

oh forgot to ask, on average how many bags of concrete, sand and stone have people used ?

Thanks Gina,

That's a great help and i really appreciate it. Regarding the concrete mix, what are people using ?

Also regarding the concrete mixing, is it ok to mix a batch, pour it, mix the next batch and pour that 10 mins later and repeat the process as i will have to mix mine in a heavy duty plastic box.

Rich.

I originally had the same idea about the skywatcher portable pier being bolted to a concrete base, but the tubing is just not big enough. 4-5" pipe will flex too much from what i have read.

Anyone got any views on placement of the pipe, should it be recessed into the hole or be at ground level just to form the column part of the pier ?

Hi Gina,

you make a good point about the concrete. I suppose a decent diameter pipe filled with concrete should give a solid pier.

during the build process, lets assume i used 8" diameter pipe which could be pvc or metal, i have seen people saying that the hole for the concrete in the ground needs to be 2-3ft deep, so firstly is this about the correct depth ?

So lets say i have my hole 3ft deep, and for arguments sake i have a 7ft long piece of pipe for the pier, would i place the pipe all the way to the bottom of the hole or would i only have the pipe inserted in 2ft into the hole leaving 1ft at the bottom for extra concrete ?

I'm assuming that it doesn't make that much difference if i use pvc or metal for the pipe in the ground as it's simply being used as the container to hold the concrete ?

Rich/

Helen,

Thanks for the link, that seems like a decent price as it's about £30 cheaper than the next cheapest altair astro one i've seen.

Rich.

Hi Gina,

The reason i ask about the diameter is because some boffin placed a post about pier construction and the diameter of the pier vs Angular deflection.

Obviously for imaging i want something super sturdy.

Pier Design: Diameter is your Friend!

The equation for angular pier deflection (given in the appendix) yields a very important relationship regarding the diameter of the pier. The angular deflection is proportional to the inverse (one-over) forth power of the diameter, that is, 1/(D^4). Let's put that into practical table of numbers.

Below we consider a pier that is 6 inches in OD. This purely imaginary pier is constructed of material like PVC pipe - it is not the steel which I recommend. Let's assume that it deflects 10 arc seconds for our 5 pound push - not a very good pier! What happens if we increase the diameter of the steel pipe while maintaining nearly constant wall thickness?

Diameter / Deflection arc seconds

6 / 10.0

8 / 3.2

10 / 1.3

12 / 0.6

Hi Malcolm, i never thought about using drainpipe. I want to use my pier for imaging, so i'm not sure if it would be thick enough for a an imaging platform. i've read a few places that a pier for imaging should be at least about 6"+ diameter but preferably 8" or more diameter.

Would love to know what diameter piers people are using for imaging ?

Also there any people on here that manufacture pier adapter plates ?

Rich.

Hi all,

I've decided to build my own pier after looking at the prices to buy pier, which seem exceptionally expensive for what they are.

Looking at construction methods, i've seen some people using 8"+ Od pipe filled with sand to suppress vibration whilst other have used thick pvc pipe in similar diameter filled with concrete.

Are there any big merits of using one method over the other ?

I plan to use the pier for Imaging.

Any recommendations for construction, greatly appreciated.

Rich.

Hi All,

Just a quick update on QHY. I previously posted about issues with a QHY9 camera and problems getting them resolved dealing direct with QHY in china. I think a lot of this can be contributed to the language barrier and Qhy not being geared up to deal directly with customers.

I'm happy to report that I managed to resolve the issue with QHY who in the end sent me a new QHY9 camera.

The new replacement camera is a totally different beast, with no fogging issues and just feels completely different and works perfectly, so I thought it only fair to now report the positive side of the story and that I now have a camera that works like a dream.

Rich.

Hi all,

I am writing this to warn people about dealing direct with QHY. Around christmas time I made the mistake of buying a QHY9 camera direct from QHY and have had a nightmare dealing with them ever since.

Basically the QHY9 camera i bought constantly fogs up which was a known issues and i was assured by QHY it was no longer an issue, and QHY have been less than helpful in trying to resolve the problem.

Basically QHY expects customers to pull apart the camera and try and fix poor manufacuturing problems yourselves. This is crazy as it should have been done right in the first place.

it's like buying a new car that doesn't work and being told by the garage to fix it yourself.

So in summary i cannot recommend QHY camera's, or if you do want one buy through a dealer and not direct to save yourself the hassle.

Well guys this is my first ever attempt at imaging. it's not very good but it's a start, and i'm pleased for my first ever attempt at imaging.

M81 - Bode's Galaxy, the seeing and transparency were pretty poor.

1x1m L, 1x1 RGB, 8" newtonian, starlight mx916 unguided.

(click to enlarge)

Rich.

Sorry guys still no break in the weather, and apparently it's going to be bad for the next week. I'll give a progress update once the weather breaks.

Sod's law the weather is getting worse......it's been sunny all day whilst i've been at work then come 4pm the dark black rain clouds rolled in. Been like that all week and i bet it rains at the weekend too just to stop my little experiment.

I'll do a series of exposure lengths, such as 15, 30, 60, 90 secs and we can compare to see if the focal reducers catch more data at the shorter exposure lengths.

So in theory, we should see a difference in the images. I.e. the 15 secs image with the focal reducer should capture more detail.

Well i have the ccd and the reducer so now i'm just waiting for the skies to clear to try and see what i get. I will post images with and without the reducer as a comparison.

Rich.

I want a reducer so that i can get a wider field of view for my MX916 CCD.

Well looks like i'm going to have to start saving again......Man this whole astronomy / Imaging hobby just drains cash like there is no tomorrow. Think it was cheaper when i used to fly planes.....lol.

Yeah this is what i'm trying to find out. what are the limits. I cant afford a big ccd, and my MX916 has limited fov, but i can't to buy a small refractor and a second ccd for imaging, hence i want to see what i can be done with focal reducers and my existing ccd which can self guide.

Steve you did......lol.

I sent you and and Ianking emails about it and you both pretty much said the same thing, that it probably wouldn't work as it was unlikely to be able to bring it to focus

So it's starting to look like the common consensus of not being able to use a focal reducer on a newtonian might being getting challeneged.

I bought the astro engineering .6x which i plan to screw directly into the nose piece of my MX916. Just waiting for the clouds to clear.

Greenkat, have you got any examples of before and after using the focal reducer. What ccd did you use for imaging ?