How do you balance the AVX mount?

[jason32]

Hi guys,

i got avx with 130pds and I am using my panasonic g7 m43 camera. Everything is fine but I am unable to balance the scope on the mount with the camera attached. it seems the camera sticking out of the focuser just pulls the scope and hard to balance? how do you guys do it? The camera is very light not like a dslr.

It seems clear tonight so want to try it out, help please.

[Thalestris24]

Hi Jason

One way to balance the scope is to do it off the mount using a piece of dowel as a fulcrum. That lets you find the DEC balance point which you can mark with some sticky point or whatever. You can than attach the scope to the mount with the balance point centered on the dovetail holder. However, sometimes it needs a counterweight attached at the mirror end though, in your case, it may not. It's a good idea to have the focus tube centered and pointing down i.e. in line with the counterweight bar. Balancing in RA is usually straightforward though you might want to arrange it to be slightly 'east heavy'. It sounds like you're not using a guidescope?

Hope you can get to try it tonight!

Good luck!

Louise

[jason32]

Hi Jason

One way to balance the scope is to do it off the mount using a piece of dowel as a fulcrum. That lets you find the DEC balance point which you can mark with some sticky point or whatever. You can than attach the scope to the mount with the balance point centered on the dovetail holder. However, sometimes it needs a counterweight attached at the mirror end though, in your case, it may not. It's a good idea to have the focus tube centered and pointing down i.e. in line with the counterweight bar. Balancing in RA is usually straightforward though you might want to arrange it to be slightly 'east heavy'. It sounds like you're not using a guidescope?

Hope you can get to try it tonight!

Good luck!

Louise

Thanks for the reply, ok I'll try to balance off the mount, yes mainly the issue is the camera pulls the scope to one side but will try it with focusor pointing down maybe then it wont pull it to one side. No I am not using a guide scope at this time but I m looking for camera and  a scope. Any suggestions for a relatively cheaper but reliable solution?

[Thalestris24]

 mainly the issue is the camera pulls the scope to one side but will try it with focusor pointing down maybe then it wont pull it to one side. No I am not using a guide scope at this time but I m looking for camera and  a scope. Any suggestions for a relatively cheaper but reliable solution?

Do you mean pulls to one side when balancing in DEC? Maybe you were trying to balance with the tube rings slackened off too much? Obviously then the tube will rotate because of the weight of the focusser + camera. You need some tension in the tube ring tighteners.

I use an Altair Astro 60mm straight guidescope + qhy5l-II mono (or Altair Astro GPCam mono) with mine. I have the guidescope fixed to a dovetail and then bolted to the tube rings - nice and solid! You could use a 50mm finder instead - a bit cheaper but the Skywatcher one needs an adapter to fit the guide cam.

Louise

[jason32]

Do you mean pulls to one side when balancing in DEC? Maybe you were trying to balance with the tube rings slackened off too much? Obviously then the tube will rotate because of the weight of the focusser + camera. You need some tension in the tube ring tighteners.

I use an Altair Astro 60mm straight guidescope + qhy5l-II mono (or Altair Astro GPCam mono) with mine. I have the guidescope fixed to a dovetail and then bolted to the tube rings - nice and solid! You could use a 50mm finder instead - a bit cheaper but the Skywatcher one needs an adapter to fit the guide cam.

Louise

I am thinking of buying the same guider setup as yours, but that comes with rings and screws, how did you attached it to dovetail bar?

Do you have this setup? http://www.altairastro.com/altair-60mm-miniguider-with-autoguider-webcam-focuser-tube-rings-multi-purpose-base.html?cat=0

[Thalestris24]

Hi

I bought the 60mm guide scope without rings and attached it to a dovetail bar using pipe clamps 

Here is a pic showing a 9x50 finder guider attached to an Al bar so a similar setup:

Probably proper clamp shells would be better but they're expensive for what they are!

Louise

ps 60mm  guiedscope is in the background!

Edited January 19, 2016 by Thalestris24

[jason32]

Hi

I bought the 60mm guide scope without rings and attached it to a dovetail bar using pipe clamps 

Here is a pic showing a 9x50 finder guider attached to an Al bar so a similar setup:

9x50_pipeclamps40pc.jpg

Probably proper clamp shells would be better but they're expensive for what they are!

Louise

ps 60mm  guiedscope is in the background!

Ok thanks I'll check

[jason32]

On 19/01/2016 at 00:54, Thalestris24 said:

Hi

I bought the 60mm guide scope without rings and attached it to a dovetail bar using pipe clamps 

Here is a pic showing a 9x50 finder guider attached to an Al bar so a similar setup:

Probably proper clamp shells would be better but they're expensive for what they are!

Louise

ps 60mm  guiedscope is in the background!

Thanks, ok I ordered the QHY II mono and Orion 50mm guide scope. I know I could connect the camera with the mount through USB, will I be able to slew to mount to different objects if needed using stellarium? or do I have to use the RS232 cable for that as well as the USB cable to the camera?

 

 

[Thalestris24]

Hi

I think the ST4 connection is just for guide corrections so you'd need the usb-serial cable for slewing and platesolving. However, you could manage by just using the hand controller. I never have - I prefer to just use a laptop  Any reason you went for the qhy5-ii rather than the qhy5l-ii mono? The latter has smaller pixels and higher qe  I imagine your Panasonic has small pixels?

Louise

[jason32]

10 minutes ago, Thalestris24 said:

Hi

I think the ST4 connection is just for guide corrections so you'd need the usb-serial cable for slewing and platesolving. However, you could manage by just using the hand controller. I never have - I prefer to just use a laptop  Any reason you went for the qhy5-ii rather than the qhy5l-ii mono? The latter has smaller pixels and higher qe  I imagine your Panasonic has small pixels?

Louise

Yes I got the QHY5 II mono, got a nice deal on that. So this ST4 connect is USB right? I'll buy the serial to usb cable too, so there will be 2 cables coming from the pc, one to camera and one to hand controller?

[Thalestris24]

26 minutes ago, jason32 said:

Yes I got the QHY5 II mono, got a nice deal on that. So this ST4 connect is USB right? I'll buy the serial to usb cable too, so there will be 2 cables coming from the pc, one to camera and one to hand controller?

Hi

The qhy5l-ii mono would be a better guide cam, I think, but never mind. There was a PHD sticky which gave info about calculating pixel scales but it's disappeared for now, at least.. There are various configurations possible. Usually people use ST4 for simplicity in which case there is a camera ST4 to mount autoguide port cable (supplied with the camera). However, if you want to control the mount from a laptop you need the usb-serial to hand controller cable. Then if you want to guide you also need the camera usb to laptop cable. So just the two cables needed.

Louise

[Thalestris24]

Hi again

I looked up your Panasonic camera - it appears to have 3.77 x 3.77 micron pixels. It has a bulb mode but only seems to allow a max of 2 min exposures? If that's the case you should be able to achieve that without guiding. At the moment you'll be imaging at 1.33"/pixel (assuming you have the SW 0.9 reducer/cc) but guiding at 6.62"/pixel. Even with sub pixel guiding that doesn't seem such a good match (though it might be doable - I'm no expert!). With the qhy5l-ii mono you'd be guiding at 4.80"/pixel which would be much better as well as being more sensitive - and it's the same price :). Also, you might be better off getting a second hand Canon EOS that will let you do very long exposures.
Just my opinion!

Louise

[jason32]

2 hours ago, Thalestris24 said:

Hi again

I looked up your Panasonic camera - it appears to have 3.77 x 3.77 micron pixels. It has a bulb mode but only seems to allow a max of 2 min exposures? If that's the case you should be able to achieve that without guiding. At the moment you'll be imaging at 1.33"/pixel (assuming you have the SW 0.9 reducer/cc) but guiding at 6.62"/pixel. Even with sub pixel guiding that doesn't seem such a good match (though it might be doable - I'm no expert!). With the qhy5l-ii mono you'd be guiding at 4.80"/pixel which would be much better as well as being more sensitive - and it's the same price :). Also, you might be better off getting a second hand Canon EOS that will let you do very long exposures.
Just my opinion!

Louise

Thanks, I just returned the qhy5-ii and ordered the L version yup its the same price . Yes I just realized my camera only does 128secs exposures and I tried taking those without guiding sometimes it works like on orion nebula it works up to 120secs, but for andromeda I could only do about 60 secs max before the stars start to look terrible. I dont have the SW 0.9 reducer? should I get that?

Yes changing the camera would be my next step, maybe in a month or so I'll get a canon or some ccd.

Also I am really annoyed by the light pollution, sometimes neighbours just leave their backyard lights on and they are so blumming bright. Any solution for that? Light pollution filter or some other filter? do they actually work? I asked this on the forum before but the answer I got was to get a £150 filter, is that the standard thing? I live in Anglesey so the sky is pretty dark here but still have to get out of the village area.

[Thalestris24]

2 hours ago, jason32 said:

Thanks, I just returned the qhy5-ii and ordered the L version yup its the same price . Yes I just realized my camera only does 128secs exposures and I tried taking those without guiding sometimes it works like on orion nebula it works up to 120secs, but for andromeda I could only do about 60 secs max before the stars start to look terrible. I dont have the SW 0.9 reducer? should I get that?

Yes changing the camera would be my next step, maybe in a month or so I'll get a canon or some ccd.

Also I am really annoyed by the light pollution, sometimes neighbours just leave their backyard lights on and they are so blumming bright. Any solution for that? Light pollution filter or some other filter? do they actually work? I asked this on the forum before but the answer I got was to get a £150 filter, is that the standard thing? I live in Anglesey so the sky is pretty dark here but still have to get out of the village area.

Hi

You will probably want a coma corrector at some point - whether you want a reducing one like the SW is a matter of choice. I have a Baader MPCC mk III on my 130pds - it's a good coma corrector but not a reducer. The SW one can cause problems with the 130pds (focus tube ingress) but the Baader is fine.

If it's just the neighbour lights you can maybe politely ask them to switch them off when you're imaging. Alternately, point your scope well away or erect a screen. Lp filters work by filtering out particular wavelengths e.g. sodium light. If the lp is white light (including the Moon) then you can't really filter it. As more and more streetlight is being made white light then lp filters are becoming less useful. Where I am my scope has to point directly towards some yellow street lights plus one only a few meters away :(. So I have an Idas Hutech lps which helps (doesn't eliminate but allows me to take longer subs than otherwise).

All the best

Louise

[ollypenrice]

People using Newts for AP don't usually have the camera sticking out of the side. They rotate the tube so the camera is underneath, or pointing at the counterweight bar, if you like. If it's sticking out sideways you'll have trouble with dynamic balance - ie balance changing position during the mount's movement. Here's a very serious bit of imaging Newtonian in action at my place, Pieter Van de Velde's home made instrument. Note the position of the camera. https://pietervandevelde.smugmug.com/Pics/Equipm/i-gStw3gg/A

Olly

[jason32]

1 minute ago, ollypenrice said:

People using Newts for AP don't usually have the camera sticking out of the side. They rotate the tube so the camera is underneath, or pointing at the counterweight bar, if you like. If it's sticking out sideways you'll have trouble with dynamic balance - ie balance changing position during the mount's movement. Here's a very serious bit of imaging Newtonian in action at my place, Pieter Van de Velde's home made instrument. Note the position of the camera. https://pietervandevelde.smugmug.com/Pics/Equipm/i-gStw3gg/A

Olly

Thanks yes I figured that out and now point my camera towards the counter weight bar and it works fine. Thats one very intimidating setup you've got there...lol

[jason32]

44 minutes ago, Thalestris24 said:

Hi

You will probably want a coma corrector at some point - whether you want a reducing one like the SW is a matter of choice. I have a Baader MPCC mk III on my 130pds - it's a good coma corrector but not a reducer. The SW one can cause problems with the 130pds (focus tube ingress) but the Baader is fine.

If it's just the neighbour lights you can maybe politely ask them to switch them off when you're imaging. Alternately, point your scope well away or erect a screen. Lp filters work by filtering out particular wavelengths e.g. sodium light. If the lp is white light (including the Moon) then you can't really filter it. As more and more streetlight is being made white light then lp filters are becoming less useful. Where I am my scope has to point directly towards some yellow street lights plus one only a few meters away :(. So I have an Idas Hutech lps which helps (doesn't eliminate but allows me to take longer subs than otherwise).

All the best

Louise

Street lights in my area are reddish yellow and most of the backyard lights are also yellow but some of them are really bright. I've asked my neighbour (very nice people) to turn their light off a couple of times but doesnt seem right to ask them everytime I take my setup out. I think the first thing is need is a coma corrector.

[ollypenrice]

28 minutes ago, jason32 said:

Thanks yes I figured that out and now point my camera towards the counter weight bar and it works fine. Thats one very intimidating setup you've got there...lol

Not mine. It belongs to a regular guest. But mine certainly intimidate me in their own way...

Olly

[jason32]

2 minutes ago, ollypenrice said:

Not mine. It belongs to a regular guest. But mine certainly intimidate me in their own way...

Olly

wow those are something...

[jason32]

I completed my setup ... well almost...here is what I got:

AVX mount
130PDS
Canon 100D modified
Hutech IDAS D1 filter
QHY5L-II guider
50mm Orion scope
A laptop just for this purpose
An intervalometer for canon

Now I've to find a software for mac

Thanks everyone for helping me get the right equipment. Now waiting for the weather to get better.

 

[jefrs]

Rotate the OTA in rings so you can access the eyepieces. I have a RACI for alignment calibration of a StarSense which is all pretty heavy so I position to counter balance the camera i.e. along the top of the Newt.  The AVX mount doesn't seem to mind the slight sideways imbalance.

Why are EQ mounts always shown with the telescope facing Polaris? They're never used like that. Rotate the Newt in its rings  to where it is in viewing position.

I also use Micro Four Thirds (MFT) cameras. The G9 is not small, it is heavier than the half-brick GH4 whereas the E-M5ii is small and light, which itself is heavier than the DMC-G7 (I've been acquiring them for years). What we can do is fit a not cheap but worth it clip-in CLS filter (STC Astro Nightscape) to knock out most but not all of the annoying terrestrial lighting.  (I'm Bortal 4/5 but with a problematic (cof) 'shielded' streetlamp).  The usual T2 to MFT adaptor is probably loo long, the depth of a DSLR light box, so a thin one is needed on the focusser. If the focusser is swung below the OTA the weight of the camera can drag it out making focussing a pain.

Unlike Canon we don't have BackyardEOS but can cable tether to either Panalympus apps, but they're far from ideal for astro. So we have to rely on the cameras, which are excellent and have built in interval timers to 1 minute exposure. Using them on wifi makes them get hot and is a bit of a waste of milk because so many functions are missing from the fondle slab app. They will also focus-peak on e.g. the moon, which helps. NR needs playing with to stop it removing faint stars.  Olympus will get a hot battery, use their power supply, but Panasonic have effective heat sinks.  The G9 eats more battery than the GH4 which has the best heat sink, but then a used G7 may be had cheaply and is very light.

[alacant]

On 07/01/2016 at 19:30, jason32 said:

camera pulls the scope to one side

Hi.

Whilst pointing at the pole, twist the tube in its mounting rings until the camera is at the lowest possible position below the tube; it's back should be nearest the ground like this.  Now balance. 3 axes. DEC, RA and the turning force of the tube itself that it remain stationary in any position in the sky when the clutches are loosened.

Cheers and HTH.

 

Edited June 17, 2021 by alacant