tooth_dr

10 minutes ago, vlaiv said:

I had my HEQ5 guide as low as 0.36" RMS.

Better thing to ask would be - which mounts guide below 0.5" RMS on regular basis.

Here are a few that can do it:

Mesu 200

E.fric

10Micron mounts

Astro-Physics mounts (not sure if all, but I'm certain that some will do that)

ASA direct drive mounts

 

Without wishing to jinx myself, my mesu e200 guides at 0.4” RMS or less regularly using an OAG (with say 30kg load and 20kg CWs).  But yes these are expensive mounts. 

4 minutes ago, david_taurus83 said:

Good old DN80!

Have some DN100 but it’s a 2m length so going to chop it half and weld a plate onto it. 

My friend delivered some free piping.
Starting building up my pier last night. This is for my solar scope so only going to be a lightweight setup <10-12kg total.

I have another larger pipe but it needs cut and a piece welded onto the base so need to dust off the welder.

Nice and fluffy looking Lee, good job!!

You can see a bit of colour noise, but imaging in the city must make it hard to get rid of this. 

On 21/10/2023 at 22:28, John said:

I've remembered another mistake. This:

 

At first glance I thought Takahashi had brought out a mini Epsilon 🤣  

My worst purchase was the high speed narrowband filters from Baader - they simply didn’t work as described - haloes, and the oiii was completely off band.  The aftersales from Baader from very poor and as a result I will never purchase Baader again.

Thankfully FLO refunded me.

15 minutes ago, 900SL said:

OK. A H section (wide flange) is better than an I section but still has significantly lower stiffness in bending about the weaker axis. Having said that, you'd likely not have any issues with a 6" (152mm) universal column section if only 1 m high with your rig. 

 A circular section is ideal, this has the same stiffness in any direction. Square hollow section also has similar properties about both principle axes and closed hollow sections have good torsional stiffness too.

Thank you.

42 minutes ago, malc-c said:

There used to be some "rule" where the norm was to make the pier base from a cubic meter of concrete, but as shown above, 600mm cubed seems adequate.  When considering options when  I was designing my observatory I looked at commercial offerings and to me they seemed overpriced for what they were.  In the end I opted for the traditional 6" drainage pipe, sunk into a big hole in the ground filled with concrete.  The tube was stuffed with rebar and filled with concrete, with the 12" rods from the base of the mounting plate for the HEQ5 sunk into that.

 

This then supported the EQ5 until I picked up the HEQ5 the following year

The mounting plate was made by a local company for a drink, but shouldn't cost more than £50 to have it turned, drilled and anodized.  I think at the time I saved myself about £300 compared to buying a fabricated pier made from steel.

This is pretty much exactly the same as my last pier, and it held a mesu mount and a few telescopes with zero issues. 

@Coolhand1988

This hole is 60cm x 60cm x 60cm.  A 120cm x 120cm x 120 seems ambitious 

18 minutes ago, Coolhand1988 said:

I plan for the cube of concrete to be around 48 inches in all dimensions

Seems very large, and a lot of digging by spade!  I have very hard rocky ground, so I had an advantage. My foundation is not too large that I can walk around the pier without touching the concrete, and I poured a separate platform to walk on physically separated from the pier foundation.

I think unless you make your pier out of a potato, it’ll be perfectly adequate.   And it’s not all about the pier itself, but what you bolt the pier to.

If your brothers offering a pier id accept that offer personally, and try to incorporate some of your preferred features into it.

I’ve had a couple of concrete piers with rats cages (poured inside a sewer pipe) and now I have a heavy duty metal pier.  Can’t say I noticed any differences.

All were incorporated/bolted onto a large sunken cube of concrete about 70x70x70cm.

The tried and tested EQ6:

1 hour ago, 900SL said:

I'm a structural engineer. What height pier and mount type/load?

Hi. I’m looking at 1m in height.  EQ6, total load 35kg (mount CWs scope).

I love the cable management. 

2 hours ago, saac said:

Vibration is not the issue that it is often made out to be , all structures will vibrate. What is important is the decay time, neither a box section nor and H beam of typical height suitably secured to the base would have a sufficiently lengthy decay time particularly if the observatory is used remotely for imaging.  Like the need for a cubic m  foundation these design characteristics take on legs  

As for wind, it is more likely to have an effect acting on the telescope itself rather than the pier; so as long as your observatory walls are offering some shelter from the wind I would not be overly concerned.  Have you had any vibration concerns on your existing pier, I would imagine the dome keeps it very well protected from wind?

Jim 

Cheers Jim. Another friend just text to say he thinks he has some 100mm or 150mm flanged iron pipe left over from a job so could be in luck.  I’ll know tomorrow when he checks sizes. 
Currently have no vibration issues that I’m aware of in the dome. No wind on the scope is one of the big advantages of the dome 

Thanks guys. If I’m imaging remotely or not moving around does it matter much about vibration suppression?  I suppose the wind could cause vibration?

26 minutes ago, saac said:

An H beam would work fine but may give you more work in attaching the pier plate, but certainly doable. 

Jim 

Cheers Jim. Good to know options 👍🏻

15 minutes ago, M40 said:

Mines made of 100mm box section, about 1M tall with a flange on each end, solid as a rock. Try and find a friendly welder, they will soon knock one of them up for you.

Would you be able to post some photos?  I’ve this one here that my friend made but I want a simpler (cheaper) option this time and I plan to weld it up myself.

Very nice Paul, did you get much last night or the night before?

Looking to erect another pier, currently trying to source some metal pipe.

As an alternative could I use a section of H iron?

Cheers!

15 minutes ago, Fedele said:

I'm curious to know what its visual performance is on the Moon and Planets. let us know

I wont really be able to give you a very meaningful report.  I'm almost exclusively an imager with scopes, and I only occasional take a look.  I was able to get very nice tight diffraction spikes visually on vega last night, and I could separate the ring passing in front of saturn quite easily.  The moon was very low when I saw it, but again looked plentiful in detail.  I was able to magnify Jupiter to 120x easily, but wasnt able to get more mag, because my eyepiece case was in the bedroom and I didnt fancy waking up the other half to grab a shorter EP.  I have no doubt it would have taken more mag easily.  I could see the bands easily and a minute amount of detail within it.  The scope had been outside for several hours at this point and was well cooled.  I chose this scope because the mirror doesnt move unlike the 260, plus it's more suited to imaging.  I dont plan to image with it until into the new year.

Good looking scope the VC200L, even on my wee old run down LXD75. The whole thing has been on point tonight, centering perfectly some easy targets (m57 m27 m13, planets, alberio) within a 15mm Meade EP every time 

Edited to add, 12:1 focuser knob fitted today also, cheers Tim.@Franklin

First light 🤩

Not really in my experience Malcolm. I live in NI too as it’s typically humid and damp. Even if the mirrors don’t get damaged, screws and the ota itself will suffer.  Lenses may get growth on them too. 

Great write up Alan.  This shows that apeture is definitely king, there is some detail in the centre crop.  I always like to look for the little birdie