What am I doing wrong?

snegron

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I see all the wonderful astro photography images posted my so many folks here, but no matter how hard I try my images look terrible. The only success I have is when I hold my cheap cell phone up to the eye piece of my telescope while photographing the moon. Nothing else yields anything remotely close to a photograph.

This is the current equipment I have:

- 10" Dobsonian scope with several eye pieces, Barlow's and t-mount adapters for m4/3 (also mounts for Nikon F and Canon EF, but that was an equal waste of time).

Main m4/3 camera is a GX85.

Questions:

- How do I fit my GX85 to my 10 inch Dobsonian? Does it go from the body directly to the t-mount and from T-mount to the scope?

- Do I need to attack it to a Barlow first?

- Do I need to place an eye piece in the Barlow in addition to mounting my camera to the Barlow?

- can someone post a pic of their set up using roughly similar equipment to what I own?

I have spent countless hours on Google trying to get answers, but no luck so far.
 

John King

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I've only ever used prime focus with my equatorial mount refractor, so it's an f/7 560mm FL with an 80mm objective lens.

Doing photography with a Dobsonian mount is always going to be difficult because of the lack of tracking.

I mount the T-mount to the camera body, then mount the T-mount directly into a sliding tube 2" adapter that then goes into my telescope focuser.
 

3dpan

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I see all the wonderful astro photography images posted my so many folks here, but no matter how hard I try my images look terrible. The only success I have is when I hold my cheap cell phone up to the eye piece of my telescope while photographing the moon. Nothing else yields anything remotely close to a photograph.

This is the current equipment I have:

- 10" Dobsonian scope with several eye pieces, Barlow's and t-mount adapters for m4/3 (also mounts for Nikon F and Canon EF, but that was an equal waste of time).

Main m4/3 camera is a GX85.

Questions:

- How do I fit my GX85 to my 10 inch Dobsonian? Does it go from the body directly to the t-mount and from T-mount to the scope?

- Do I need to attack it to a Barlow first?

- Do I need to place an eye piece in the Barlow in addition to mounting my camera to the Barlow?

- can someone post a pic of their set up using roughly similar equipment to what I own?

I have spent countless hours on Google trying to get answers, but no luck so far.
Have you tried photographing the stars with just a lens attached to your camera ?

Instead of "jumping in the deep end" using a high magnification, non-tracked Dobsonian telescope. That is a recipe for disaster for a beginner to the astro world.

Cheers,
 

MadMarco

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- How do I fit my GX85 to my 10 inch Dobsonian? Does it go from the body directly to the t-mount and from T-mount to the scope?

- Do I need to attack it to a Barlow first?

- Do I need to place an eye piece in the Barlow in addition to mounting my camera to the Barlow?

- can someone post a pic of their set up using roughly similar equipment to what I own?

I have spent countless hours on Google trying to get answers, but no luck so far.
I'll try to answer your questions as succinctly as possible

1) There are 2 ways to do this, one significantly better and potentially more complicated than the other. Your (and most other) telescopes are not designed for photographic use, so the light coming from the main mirror or lens is curved and then focused with an eyepiece. A camera sensor is flat and won't like this, the center will be focused and the edges out of focus. To correct this you would need a field-flattener, more about this later

1a) For a minimum you need to buy a Micro 4/3 T2 adapter like this:
https://www.harrisontelescopes.co.uk/acatalog/panasonic-olympus-micro-4-3-t-ring-43micro.html this will attach to the bayonet fitting on the camera and present you with a T2 thread (M42 0.75mm pitch) thread.

You will then need to attach this to your telescope and will need an adapter. Word of caution here, an M42 thread is usually 1.0mm pitch which is different to the M42 0.75mm thread pitch of a T2 thread so make sure that you buy the correct adapters (astro equipment is not very user friendly). The easiest way to attach the T2 adapter would be to use a push fit adapter into your focuser, hopefully this would be 2" so one of these:
https://www.harrisontelescopes.co.uk/acatalog/explore-scientific-t-adapter-2-inch.html#SID=26

If your focuser is threaded, then you could and probably should use a threaded adapter, they will be more secure and accurately aligned.

Also depending on your focuser you will probably need a T2 extension to get focus (your focuser probably won't go far enough out). You could try at first, but a T2 40mm or more extension might be required.

1b) The other way would be to use a field-flattener. This will produce much better results, but... you need to match the field flattener to the telescope. You will either need to contact an astronomy shop or go to astronomy specific forums to find someone who has the same equipment as you. A field-flattener probably won't need an extension. This is what a field flattener looks like, but don't buy this specific one it won't work well for you:
https://www.harrisontelescopes.co.uk/acatalog/skywatcher-field-flattener-2.html#SID=251

2) Do not use a barlow (at least at first) it magnifies everything and makes every problem that much bigger (seriously).

3) No, you won't use an eyepiece or a barlow with a DSLR

4) I have a short-tube refractor for deep space imaging, so I can't show you exactly what it all looks like, but it should go like:

[Telescope] [Adapter to T2] [Extension (probably] [M43 to T2 Adapter] [Camera]
or
[Telescope] [Field Flattener] [M43 to T2 Adapter] [Camera]

I recommend you search https://www.cloudynights.com/ forum and if you don't find something, post in the beginners astrophotography section. Good luck!
 

Mark73

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Sep 13, 2019
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You really need to distance yourself from the idea of using a 10" reflector as a first step into astrophotography, unless moon images are all your after. You are better starting off with a wide angle prime and a tripod, just to get you head around frame and focusing.

Once you have had your fill if this, then you can start to think about maybe using a camera tracker for unguided normal-telephoto lens imaging. This will teach you polar alignment, for which you will need here on out.

For DSO AP, a 10" ota will require accurate (preferably off axis) guiding, and at the very least an EQ6-R class mount.

Even that would be borderline in my opinion, so you better have deep pockets.

BTW, most supplied camera mounts for astro optics tend to be Canon EF based, so I use a widely available EF to m43 adapter, with the benefit of using many adapted optics.

There is also room to mount 2" astro filters in some of these adapters, as I have.
You just need to bond a 48mm-46mm step down ring inside with epoxy.

HTH
 

snegron

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  • Thread Starter Thread Starter
  • #6
You really need to distance yourself from the idea of using a 10" reflector as a first step into astrophotography, unless moon images are all your after. You are better starting off with a wide angle prime and a tripod, just to get you head around frame and focusing.

Once you have had your fill if this, then you can start to think about maybe using a camera tracker for unguided normal-telephoto lens imaging. This will teach you polar alignment, for which you will need here on out.

For DSO AP, a 10" ota will require accurate (preferably off axis) guiding, and at the very least an EQ6-R class mount.

Even that would be borderline in my opinion, so you better have deep pockets.

BTW, most supplied camera mounts for astro optics tend to be Canon EF based, so I use a widely available EF to m43 adapter, with the benefit of using many adapted optics.

There is also room to mount 2" astro filters in some of these adapters, as I have.
You just need to bond a 48mm-46mm step down ring inside with epoxy.

HTH

Unfortunately, I live in a city where it would be darker if it were not for my neighbors who enjoy lighting up the exterior of their houses all night as a form of "architectural decor ". So, a wide angle lens on a tripod is definitely not an option for me (I live in Florida, so there are no dark places anywhere in the state...at least none that are located on public property). That limits me to having to use a telescope of some sort.

Sadly, I have spent a wagon load of money on photography equipment throughout the past few years (currently own crop frame and full frame dslr's and lenses in both Canon and Nikon plus my Panasonic gear); purchased T-mounts for Canon EF, Nikon F and m4/3, tried all sorts of combinations to get at least one decent pic, but all failed.

I tried selling off some of my gear, but all the offers I was getting were ridiculously low for almost new equipment, so I decided to keep what I have and make the best of it (plus, I use most of it with kids at a photo club I run at a local school).

What I find frustrating is that I can see planets fairly well with my Dobsonian scope, but I can't capture these images with any of the gear I currently have (except with my cell phone when I point it through the eye piece).
 

MadMarco

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Machi

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- How do I fit my GX85 to my 10 inch Dobsonian? Does it go from the body directly to the t-mount and from T-mount to the scope?
Yes, you can directly join camera to telescope's T thread via T2->M43 adapter.

- Do I need to attack it to a Barlow first?
No. Your camera can work without Barlow with your telescope.
Telescope will work as big lens (10" will be something like 1200mm f/5).

- Do I need to place an eye piece in the Barlow in addition to mounting my camera to the Barlow?
No, camera should be connected to Barlow without eyepiece.
Barlow is teleconverter so it practically means longer focal length and lower aperture.
Barlow is good for planets but connection to camera can be problematic.
Best is Barlow with T thread (I have such one).

- can someone post a pic of their set up using roughly similar equipment to what I own?
I have 8" Dobson so I will send some photos tomorrow.

BTW!
You don't need field flattener for Dobsonian (Newton type reflector telescope)
if you don't have proper tracking mount and you don't want to do wide field astrophotography.
Even then coma corrector is more useful for reflector.
Field flatteners are more useful for refractors.
 
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Machi

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May 23, 2015
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717
Here are promised images of (some) setups for astrophotography.

Part 1.
Basic connection of camera and telescope via T/T2 thread:

1. Telescope with 2" eyepiece holder.

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2. Addition of 2"->T/T2 thread adapter (it's mostly supplied with the telescope).

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3. Addition of T/T2->M43 adapter (it's not supplied with the telescope).

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4. Final setup with camera connected via T/T2->M43 adapter.

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Machi

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Part 2.
Camera connected to telescope via Barlow with T thread:

1. Addition of 1.25" eyepiece holder to the 2"->T/T2 adapter (I had both supplied with telescope).

Dp6.jpg
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Dp7.jpg
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2. Connection of Barlow via 1.25" eyepiece holder.
This Barlow has T/T2 thread. For Barlow without thread, one needs additional 1.25"->T/T2 adapter.

Dp8.jpg
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3. Final setup with camera connected via T/T2->M43 adapter.

Dp9.jpg
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Machi

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Part 3.

Other options:

Here is connection of camera to the telescope via T/T2->FD adapter and FD->M43 focal reducer.
This combinations removes one annoyance with basic T->M43 connection.
Problem with pure Newton reflector ("Dobsonian") is that it's open system.
If there is an aerosol (pollen, dust etc.) in the atmosphere, it has free way directly to the sensor of camera.
With focal reducer (or Barlow), this transmission of aerosols is greatly reduced.

Dp10.jpg
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Other option is using eyepiece in similar way as Barlow lens.
I don't use this combination but there is some info about it here.
More advanced option is to use coma corrector between Dobsonian and camera.
In most cases coma corrector goes to the 2" or 1.25" eyepiece holder and camera is then attached to the coma corrector via T/T2->M43 adapter.
 
Last edited:

PakkyT

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Ya know this post reminds me this would have been a great application of the Olympus Air camera. It is too bad Olympus didn't open up the SDK more to allow more customization. perhaps making it more popular, and then perhaps newer models available today. But looking at your setup, it just screams "Air" as a perfect form factor for this type of photography.
 

Machi

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Messages
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Ya know this post reminds me this would have been a great application of the Olympus Air camera. It is too bad Olympus didn't open up the SDK more to allow more customization. perhaps making it more popular, and then perhaps newer models available today. But looking at your setup, it just screams "Air" as a perfect form factor for this type of photography.
Olympus Air camera would be great if it would be open system. Open source software for control and highly adaptable body (for example possibility to add Peltier cooler, EVF, display etc).
 

snegron

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  • Thread Starter Thread Starter
  • #14
Part 3.

Other options:

Here is connection of camera to the telescope via T/T2->FD adapter and FD->M43 focal reducer.
This combinations removes one annoyance with basic T->M43 connection.
Problem with pure Newton reflector ("Dobsonian") is that it's open system.
If there is an aerosol (pollen, dust etc.) in the atmosphere, it has free way directly to the sensor of camera.
With focal reducer (or Barlow), this transmission of aerosols is greatly reduced.

View attachment 825742

Other option is using eyepiece in similar way as Barlow lens.
I don't use this combination but there is some info about it here.
More advanced option is to use coma corrector between Dobsonian and camera.
In most cases coma corrector goes to the 2" or 1.25" eyepiece holder and camera is then attached to the coma corrector via T/T2->M43 adapter.
Thank you for posting these images!
 
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