First unguided attempt ASA DDM60

[jjongmans]

My first attempt of unguided imaging with the ASA DDM60 Direct Drive Mount. My goal is to achieve 20 min unguided @ 2000mm f/8.

Straight out-of-the-box 5 minute unguided result.

M37

2000mm f/8 reduced to 1383mm f/5.53 with CCDT67 reducer

0.804"/px = FOV 33.6' x 44.6'

Unguided

1x 300s (5 min) Luminance 1x1

-30°C

manual focus

bias subtraction + bpm

no darks / flats

HistogramTransformation in PI

full resolution

To achieve 20 min. I need to improve:

- Polar alignment, I have to repeat the PA software routine, I only did it once.

- Balance, that is very critical with a direct drive, i only did a quick balance.

- PID settings of the motors, I only did an autotune.

- Collimation, still not at the right spot.

[Gina]

Nice clear cluster

[Martin-Devon]

Looks extremely good, it must be one heck of a good polar alignment software programme in that ASA mount, coupled of course to the superb mechanics as well. Keep us posted on how the longer subs fare, it looks like with minimal tweaking you'll get to the lengths you want unguided. As a matter of interest, how long does it actually take to run through one iteration of the polar alignment steps with the ASA?

[jjongmans]

@Martin-Devon

This mount is developed for unguided imaging; no periodic error, no backlash, high res encoders, tracking controlled with an accurate sky model. Polar alignment is quite simple. There's a green laser to point it at Polaris. Then I create a small pointingmodel for the polar alignment, center a star, the mount moves the star and I recenter it with the bolts. I can repeat this a couple of times, I only did it once in this example. After that the real magic happens, the modeling of setup and sky.

[Martin-Devon]

Jeffrey, thanks for the info - by the way, your website is fantastic...

[badgers]

Sounds similar to the polar alignment with the Synscan Beta Polar Realign feature. With 4-5 iterations mine is usually indistinguishable from a drift aligned PA.

But crikey that's a great unguided image, if you can get 10-15 minutes unguided from it I might have to start saving.

Anton

[jjongmans]

I'm confident that I can achieve 20 minutes, if I improve the balance and PID settings of the motor controls. This is an example without further tweaking the parameters. I just need some clear skies (don't we all?).

[r3i]

Excellent image, you must be very encouraged by that result.

Brilliant images on your website too and looks like you have built up a very nice collection of equipment.

[DMouse]

Thats a great starting image. I'm looking forward to some great pics from that mount. I have been reading about the ASA mounts for some time, and drooling!! I have always had a dream mount at the top of my list. It was the Paramount MX, now its the ASA DDM60!! One day I hope to have the funds to get such a beauty.

Clear Skies

Paul

[jjongmans]

Thank you all, I'll keep you updated!