10 replies to this topic

[Astrofriend]

My latest project.

 

Camera:

A Nikon D800 full frame camera. First thing to do, remove the IR filter and the others.

 

http://www.astrofrie...nikon-d800.html

 

In somehow remote control it from KStars/Ekos or PC Windows with APT.

 

Lens:

A Pentax 645 FA* 300mm f/4 ED lens

 

http://www.astrofrie...45fa-300ed.html

 

Make them fit together with 3D printed parts

Add Off-axis adapter
Add Tilt adapter

Longtime project for sure.

 

Lars

Edited by Astrofriend, 04 June 2024 - 05:15 AM.

[Astrofriend]

Today I started to design the adapter that will connect the Nikon camera to the Pentax 645 lens. I have divided it in two different devices to get it easier to 3D-print.

 

Here is a prototype of the end of the adapter that connect to the Pentax 645 lens:

http://www.astrofrie...nikon-d800.html

 

The camera and the lens weights 2.7 kg together, I'm not sure if the strength of the adapter will be strong enough.

 

Lars

[Astrofriend]

Now the prototype adapter is almost finished. I can now connect the Nikon camera to the Pentax 645 lens system.

 

I have included a holder for 2 inch IR/UV cut filter, off-axis adapter.

 

Latest project page:

http://www.astrofrie...nikon-d800.html

 

When skipping the Nikon bayonet I got a much bigger opening, now 46.5 mm, good for full frame sensors.

 

Lars

[Astrofriend]

Some more photos and information. The last is that I started to design the focus system:

 

http://www.astrofrie...nikon-d800.html

 

Lars

[Astrofriend]

More updates:

 

I have made 3D-printed brackets: focus driver, triple DC/DC box. The computer  can be a mini PC Windows or a Raspberry Pi5. Computer power by either  a 12/18 volt 3 Amp DC/DC converter or a 12/5 volt 5 Amp DC/DC. If my idea about a Nikon D800 camera don't work well for astro it's easy to convert to my old Canon 6D.

 

Details here:
http://www.astrofrie...nikon-d800.html

 

The last thing I did was a 3D-printed dove tail and on top of that a main bracket that holds all the devices together.

 

Missing the stepper motor and a pivot bracket to it.

 

Lars

[Astrofriend]

Today I got the stepper motor that I will use for the focuser. Installed it today too.

 

Here is the latest, most pages with updated photos and text:

 

http://www.astrofrie...nikon-d800.html

 

Now I can power up the Raspberry and do some test.

 

Lars

[Astrofriend]

Today I could do the first test to communicate with the Nikon camera. I started with the Windows system and used APT. It worked very well, none of the problem I have read about using a Nikon camera, maybe that bad reputation was for earlier models than mine.

 

Here is my documentation:

 

http://www.astrofrie...nikon-d800.html

 

Lars

[Astrofriend]

First Light

Isn't it very exiting when testing a new device for the first time. This night I did my first test of the Nikon D800 and the Pentax 645 FA 300mm ED f/4 lens.

After some strugle I got an image, not very good because not all of the equipment is finished yet.

 

This is how it looks:

http://www.astrofrie...nikon-d800.html

 

It look promissing to me. After this first test I had built a new motor focuser system, based on MyFocuserPro2. Almost exact the same design as my earlier one. It worked imediately after I power it up.

My biggest problem now is to get the ASI120 guide camera to work. This camera has some problem with Linux, I had it flashed with a new software, but still it doesn't work as it should.

 

Lars

[Astrofriend]

A couples of nights ago we had a clear sky. I took some photos of the galaxy M81. That galaxy I have some photos from with my older equipment and I can now compare the two systems.

 

The Nikon D800 & Pentax 645 FA 300mm ED f/4
vs
Canon 6D & Pentax 645 300mm ED f/4

 

Of course not perfect control of the environment but still very exciting to compare them. That's important for me, which camera shall I spent the time with and which lens ? One of the cameras I will remove the filters from and the mirror as well.

 

Here is the first images to compare and some data I have collected about the cameras:

 

http://www.astrofrie...nikon-d800.html

 

There isn't much difference, but I prefer the Nikon D800 with the Pentax FA lens.

 

Do you feel the same ?

 

Lars

[Astrofriend]

Every night there is a clear sky I take out my new equipment on the balcony. Take a lot of test photos, I'm on the go to build the tilt adapter, just waiting for some parts that I have ordered.

 

For you who curious how the the combination Nikon D800 and Pentax 645 FA 300mm f/4 ED perform I have som examples here:

 

http://www.astrofrie...en-cluster.html

 

http://www.astrofrie...en-cluster.html

 

http://www.astrofrie...ary-nebula.html

 

Look at the high resolution images. Even if there is some tilt I'm impressed. But to be honest, the older version of the Pentax 645 isn't bad either, the one without "FA" letters.

 

The of-axis guiding help a lot compare to the older guide telescope.

 

The Nikon camera has a lot of pixels. What's just a dot in center can be zoomed in and then you have something there. But it eating my hard drives in a fast pace.

 

Soon I will be out at a dark place and taking photos.

 

Lars

[Astrofriend]

Now I got the first surface mirror delivered. They are normally used in video projectors and then mass produced. They sell them cheap, 2 Euro each. I made an adaptor for the mirror that fit my off-axis adapter. The older one was made for a prism. The off-axis adapter is the new design I made and it has a tilt adjuster too. I was able to do some test to see if the guide camera receive any light. And yes it did, much brighter now with the bigger opening. But if I could move the mirror one mm closer to the optical axis it will be even better. The edges of the mirror protrude out in the light beam to the main camera. I have to grind down these edges in a 45 degree angle. I don't think that will be a big problem to do.

 

I took some new pictures of the equipment, look at the end of the page:

http://www.astrofrie...nikon-d800.html

 

At the home observatory I works terrific, but out on the field I use the WIFI spot function. There is some wrong with the setup of the Raspberry. The WIFI transmitter looks to go down often and interrupt the connection. I read somewhere that the hardware can be setup in "g" mode, not "n" mode and then be much faster response. From the tablet to the Raspberry it's fast, but the answer is the one that is delayed, from seconds to minutes.
I will take a new look at the problem. It's setup in non sleep mode, something else that cause this.

 

This is what I have done to the WIFI spot setup (at bottom):

http://www.astrofrie...spberrypi5.html

 

Lars