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First Light DDM60 PRO & 10" Carbon RC, unguided

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#1 jjongmans

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Posted 11 December 2012 - 08:03 AM

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

my setup

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.

#2 J.P.M

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Posted 11 December 2012 - 08:37 AM

Congratulations from the snowy Finland! Looks to be one amazing setup.

#3 Konihlav

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Posted 11 December 2012 - 08:41 AM

looks good! congratulations to the new mount :) (BTW I should have a new mount too, within a month).

at this focal length the star clusters (that I normally find boring) starts to become interesting :)

#4 Leonardo70

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Posted 11 December 2012 - 09:25 AM

Great setup .. congrats for the first light ..
Happy to see a lot of user of this scope...
I just created a new group about GSO RC owners:
http://www.facebook....ups/GSORCAstro/

Feel free to join.

All the best,
Leo

#5 jjongmans

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Posted 11 December 2012 - 01:48 PM

Thank you all.

@Leonardo70
I joined the group, hope many will follow.

#6 SL63 AMG

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Posted 12 December 2012 - 05:43 AM

Nice setup. I think you are going to have a lot of fun with that equipment. I had a QSI583wsg and liked it quite well. I would have kept it but had to switch to an FLI because of the 30 second slow download times, which I believe have been corrected in your 683 model. The 683 wasn't yet released when I bought the FLI.

I have the Astro-Tech AT12RC, which I believe is manufactured by GSO. I am using it right now to image NGC2403 and I am quite happy with it.

Of course, it is much heavier than your carbon fiber 10" so I have a DDM85 mount to push it around.

Anyway, you image looks great. Enjoy your new toys!

#7 alpal

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Posted 12 December 2012 - 07:18 AM

The ASA DDM60 Direct Drive Mount is fantastic to do that unguided.
I think we'll see more & more of these direct drive mounts.
You may need an OAG for 20 minutes though.

#8 jjongmans

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Posted 12 December 2012 - 09:48 AM

@Dave
The 683 is a bit faster than the 583, but unbinned it still takes 13 sec. No issue when subs are 20-30 minutes. For focusing I can use subframes.

@alpal
I'm convident that this mount is capable of 20-30 minute unguided tracking, but I already have OAG (embedded in the QSI WSG body) with a Lodestar autoguider.

#9 alpal

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Posted 12 December 2012 - 03:17 PM

"20-30 minute unguided tracking"

I know they say that but then again
how accurate would your polar alignment & elevation setting have to be?
What if your elevation or latitude was 0.01 degrees out?
Also - I believe that that axis is adjusted by allen head screws -
not a large adjustable knob for fine tuning.
Is it really possible?

My bet is on using your OAG.

#10 jjongmans

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Posted 12 December 2012 - 05:00 PM

@alpal
This night I managed to shoot a 20 minute UNGUIDED subframe (through thin clouds, so signal is bad) with round stars! :)

IC410
2000mm f/8 reduced to 1383mm f/5.53
1.608"/px = FOV 33.6' x 44.6'
Unguided
1x 1200s (20 min) 3nm Ha 2x2
-40°C
manual focus
no calibration
HistogramTransformation in PI

image

Too bad the weather is ^&*(^(, because I'm very excited with this mount!

#11 jjongmans

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Posted 12 December 2012 - 05:14 PM

how accurate would your polar alignment & elevation setting have to be?
What if your elevation or latitude was 0.01 degrees out?
Also - I believe that that axis is adjusted by allen head screws -
not a large adjustable knob for fine tuning.
Is it really possible?


It is possible, I just saw it... :)
With the software you can do an accurate polar alignment routine, it's pretty simple to get within 5-10' PA.
Elevation isn't an issue, because the sky is modelled and also all errors of mount and telescope.
There are fine tuning adjustment knobs voor alt/az adjustments

#12 SL63 AMG

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Posted 12 December 2012 - 09:16 PM

@Dave
The 683 is a bit faster than the 583, but unbinned it still takes 13 sec. No issue when subs are 20-30 minutes. For focusing I can use subframes.


Thanks. Downloading image subs is really not the problem. The problem with the slow download speed rears its ugly head when making pointing models for measuring error.

Polar misalignment of 5-10 arc minutes can easily be corrected for 5-15 minute subs by using MLPT. When expposing 20 to 30 minute subs, a polar alignment <1 arc minute is really necessary. In order to get that accurate PA one needs to make a couple of 20-30 star pointing models, at least twice and often three times. This becomes painful with 13-30 second download times per image.

With my FLI ML8300 I can make a 100 star pointing model using 4 second exposures, a 1 second settle time and a slew for each sub in under 40 minutes.

Otherwise, I think QSI makes awesome cameras and I wish I had the built in OAG on my FLI.

#13 alpal

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Posted 13 December 2012 - 02:32 AM

@alpal
This night I managed to shoot a 20 minute UNGUIDED subframe (through thin clouds, so signal is bad) with round stars! :)

IC410
2000mm f/8 reduced to 1383mm f/5.53
1.608"/px = FOV 33.6' x 44.6'
Unguided
1x 1200s (20 min) 3nm Ha 2x2
-40°C
manual focus
no calibration
HistogramTransformation in PI

image

Too bad the weather is ^&*(^(, because I'm very excited with this mount!


20 minutes unguided - that's amazing.
It must be true & it's almost unbelievable.
Maybe it's just because I am used to my NEQ6 mount. :)

#14 alpal

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Posted 13 December 2012 - 02:35 AM

how accurate would your polar alignment & elevation setting have to be?
What if your elevation or latitude was 0.01 degrees out?
Also - I believe that that axis is adjusted by allen head screws -
not a large adjustable knob for fine tuning.
Is it really possible?


It is possible, I just saw it... :)
With the software you can do an accurate polar alignment routine, it's pretty simple to get within 5-10' PA.
Elevation isn't an issue, because the sky is modelled and also all errors of mount and telescope.
There are fine tuning adjustment knobs voor alt/az adjustments


Ok - that explains it - it's electronically correcting all errors.
We are are welcomed to the 21st century!

I think I'll have to include a DDM60 in my future budget. :)

cheers
Allan

#15 jjongmans

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Posted 13 December 2012 - 03:33 AM

@Dave
There are two downloadmodes for the QSI, for quality (13s, unbinned) and fast download (4s, unbinned).

#16 Mark72

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Posted 13 December 2012 - 03:54 AM

Nice set up indeed.
I also can't get enough from RC 10/ QSI ;)

Mark

#17 darkforce

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Posted 13 December 2012 - 04:54 PM

Great Setup.
Looking forward, to see your spectacular pics

Immo






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