[Theme] Night sky shots

[John Geerts]

Impressive results Armando.  Like it.

[ColinM]

It's been a while since I checked this thread, but just wanted to add my admiration and praise for your most recent results Armando

You are doing an amazing job with that lens!

Ditto.
As someone once said, it's not just what you've got - it's what you do with it that really counts

[Akira]

That depends on the phones operative system - guess which deep space object is on my Android based one    (shown early in this thread. Actually Amando's Orion nebula would have looked very nice too).

Mine is iPhone SE, so the vertical version should fit.   

[Hugh_3170]

+1

Armando, nice work indeed.

(BTW Colin, I believe that your quote was the one once made by an actress to a bishop....................  )

It's been a while since I checked this thread, but just wanted to add my admiration and praise for your most recent results Armando

Ditto.
As someone once said, it's not just what you've got - it's what you do with it that really counts

[Hugh_3170]

Agreed, but then so to is your moon shot Peter - one of the nicest that I have seen for a while.

Thanks Armando That shot of yours is stunning!

[atpaula]

Very nice images Armando!

[Peter Connan]

Agreed, but then so to is your moon shot Peter - one of the nicest that I have seen for a while.

Thanks Hugh, I appreciate your kind comment.

[armando_m]

Thanks Akira, Peter, Øivind, John , Colin, Hugh, Aguinaldo

I'm surprised also on the amount of detail on the Orion nebula captured with the 70-300 zoom, I guess a lot has to with the darkness of the location, clear skies, and how bright that particular nebula is

Here are two more images, not as spectacular as the object look flat instead of 3d

1. Orion wide filed, taken with the 85mm f1.8AFS, at F/4, 30 secs exposures, ISO 800, 69 exposures, 34.5 mins total exposure, 20 darks, 20 offset frames
2. Flame and horese head, 70-300VR AFS, @250mm F/8, ISO 1600, 20 sec exposures, ISO 1600, 90 exposures, 30  min total exposure, 20 darks, 20 offset

Edit adding a map of the location

[Akira]

Armando, you continue to load this thread with amazing images!

One question: are these images cropped from the full FX frame to any extent?

[armando_m]

Armando, you continue to load this thread with amazing images!

One question: are these images cropped from the full FX frame to any extent?

yes they are cropped, the last image of the Orion nebula is 1200 x 1800 pixels, horsehead 2900x2100, wide field 3500x2800

the Orion nebula will still make a nice 6x12 print

[Akira]

Armando, thank you for the details.  The frame size of the wide field image seems to (very) roughly correspond to that of m4/3 format.

[armando_m]

I'm trying to solve the reduced amount of time the tracker is able to handle my front heavy 70-300+D800
At the moment the camera is mounted on the original tripod mount (via an Lbracket)

The objective will be to mount the camera with the center of gravity on the turning axle and therefore reducing the load on the tracker motor, which I would think will improve the precision  and allow longer exposures

I borrowed an image from Øivind and added arrows to show the movement I would need to be able to do with my camera

I found a nodal rail that seems to meet my needs but I'll probably reach to a local fabricator ,  instead of buying it from b&h , and importing it

[Seapy]

Could you not add a counter balance arm as is used with some telescope mounts to compensate for the heavy tubes?  Moving the assembly back may not actually improve the balance completely because of the leverage caused by the mass being mounted away from the actuator motor.  An arm is low tech and much even improve stability too?

[armando_m]

Robert, thanks for your comment.

ioptron actually sells the counterweight, so I did some experimenting with a counterweight, here is an image of a  crude implementation.

When I put this on an axle that allows it to turn freely (large screw driver), after a few degrees it will tend to turn so all the weight above the line between the ball head and weight will rotate to stay upside down (red triangle),  the torque is higher than just mounting the ballhead camera directly on the tracker, being counter productive to what I'm trying to achieve

My next attempt was moving the ball head away from the line formed by the weight and center of rotation (sorry no images), with the center of gravity of the camera aligned with this line, that was stable on the free axle regardless of the turning position, but stability was lost with different positions of the camera/lens, once again becoming unstable.

so, I'll do some trials mounting the camera with the center of gravity on the turning point of the tracker, you have much more mechanical experience than I and you are probably right, but I want to feel if the balancing the camera lens on the turning point actually helps or not

[Seapy]

I have no experience of this but seems to me you need to find the centre of balanced of the lens and body, both lengthwise and height, that should revolve around the output shaft of the motor, I would have thought.  That way it would (should?) spin with no bias in any direction, no 'uphill' struggle  or 'downhill' runaway.  Something like a Wimberly head bracket?