ATC-02

My ATC-02 had a problem. The red light was on but it would talk to the PC. The baffles would open and close using the buttons on the scope but nothing else. The Officina Stellare crew where great, and after awhile its repaired and operational. Temperature controlled mirrors, fans, baffle control all at the touch of a button again. First light was last night after only getting it back the day before (not sure what happened to the usual astronomy curse). Its a pleasure to use.

RILA Collimation part 2

Its been a while, a very frustrating while. So much so that I had almost given up ever getting the collimation complete. Persistence is apparently the key.

I learnt two things.

1) the secondary mirror has 4 small hex bolts that adjust the shape of the stars. They can be set to distort the image. Moving these a small amount can bring the star into round. The problem with this is that if the primary mirror is not adjusted correctly as well its a move this, check, move that check back and forward. All of this on a defocused star (both sides of focus) smack in the middle of the image. Do no deviate even a little from the center, plus or minus 10 pixels in my case was enough to distort it.

What the central out of focus stars look like (finally) image

2) Move the tip tilt plate out about 0.5mm all round and confirm the spacing with a feeler gauge. Make sure you know how the screws line up with the image, put your hand in front of the telescope so that its in the same relative position as the screw but at the front of the scope, take a picture and document where each screw lines up. Move the rotator so that the screws are aligned to with the image so that the triangle they form has one side lined up with a rectangle of the CCD image. When the stars look like horse shoes on the edges do up the screw, when they look like diamonds or triangles undo the screws. Movements are very small, 1/4 turns at a time. Start with the most out of shape stars.

Alignment of the tip tilt screws and the image. image
The tricky bit is knowing when the primary mirror alignment stops and tip tilt should start. On my Proline 16803 image the horseshoe stars where only about (note the ABOUT) two/three times as long they where wide. 1/4 – 1/2 turn made these very close to round in the corners. Just refocus after each adjustment.

These are the horseshoe stars. image

These are the diamond stars.image

This is of course after the distortion correction above.

These scopes are a bugger to collimate and I will not be buying another one. Longer exposures will have to do.

Still the tech support form the Officina Stellare guys was very good and the final result is actually quite pleasing. Not perfect but close.

Final image, combined, stretched.

image

M20 & M21 in narrowband

This is M20 & M21 in narrowband, Hubble palette.

M20 M21 v2

NGC 6357 Narrowband

This is NGC6357 in narrowband, Hubble palette.

NGC 6357 v2

The sun

First real go at the Sun. Canon 5D, Willam Optics Megrez 72, Orion White filter. Photoshop processing was only unsharp mask and shadows/highlights.

sun jul 2014 v2