NGC 6357&6334 in 3nm HA

[avandonk]

Managed to jury rig some guiding with bits I found around the place.

Large image 6MB

http://d1355990.i49.quadrahosting.co...6334_HA3nm.jpg


Exposures 10x4 min. Cloud came in otherwise there would be more.

This gives a better idea of where we are in alignment.

I forgot to say corrected with flats and darks only.

Bert

[Paul Haese]

Yes that is looking the goods. Heaps of detail. Bit of rotation in the bottom left hand corner and maybe a little tilt in the top left hand corner.

Time to get a battery of darks, flats and biases done too.

[strongmanmike (Michael)]

I see a pig in mud there

Deep

Mike

[avandonk]

The last image was stacked with Deepskystacker which is lousy at handling rotation with any distortion.

Here is a version of the same data stacked with RegiStar 16MB

http://d1355990.i49.quadrahosting.co.../RGST_vers.jpg

It is upsized by a factor of 1.6. It shows the real star profiles in the corners.

Never mind the nuances of nebular detail just pixel peep at the corners.

I am happier than the pig Mike's fevered ancient brain can see in random spatterings of dust and gas.

The lodestar guider just arrived.

Bert

[gregbradley]

That is very impressive Bert. Those stars are nice and round in the corners and the streaky ones are just polar alignment a bit off plus autoguiding a bit off. No big deal. So your scope is corrected further out than they specifiy. That's a nice bonus.

A lot of detail showing up for short exposures.

By the way it may pay to simply do Ha 2x2. I usually do that on the CDK17, but then I suppose it has a lot of aperture. You don't lose much with 2x2 but there is a big gain in the signal to noise. Its worth trying.

That's a very exciting result and a very good choice of target.

RH200 now on my possible to get list! These Riccardi Honders scopes are amazing.

Greg.

[Peter Ward]

Looks like you need to reduce the data a bit better (noise and hot columns are not a good look). CCD inspector says there is a *slight* tilt in the system, but hey you would not be Robinson Crusoe there and nothing a little shim stock can't fix.

Looks like a very tidy scope Bert.

[avandonk]

Thanks Greg. It is still very early days.

I have to now use the imaging system to tune the mount. The mount will then make the imaging system work far better.

Bert

[avandonk]

Originally Posted by Peter Ward

Looks like you need to reduce the data a bit better (noise and hot columns are not a good look). CCD inspector says there is a *slight* tilt in the system, but hey you would not be Robinson Crusoe there and nothing a little shim stock can't fix.

Looks like a very tidy scope Bert.

Peter us DSLR blokes are not used to dealing with column defects or noise.

I purposely went down to the noise as this shows there is no fudging.

The RH200 has adjusters behind the Atlas focuser for collimation and optical path alignment.

Bert

[Peter Ward]

Originally Posted by avandonk

The RH200 has adjusters behind the Atlas focuser for collimation and optical path alignment.

Bert

Wow, Really? The Honders design has very tight tolerances for optical alignment so I am surprised they didn't encase that bit in cement at the factory and put on a large "hazmat" sign.

Tilt can come from sources external to the scope (small planar differences in focuser, filterwheel, camera faceplate) hence I'd much rather make small adjustments there rather than tinker with the optics.

[avandonk]

When I said behind Peter I meant at the back of the RH200 in front of the Atlas Focuser.

There are three bolts for collimation that can be adjusted independently without any need for locking. There are also four bolts for tilt adjustment to put the optic axis on the 'new' collimated axis.

We are designing a cradle that will hold the Atlas focuser filter wheel and camera in situ. It is just a matter of releasing the Atlas focuser from the back plate of the RH200 by means of the Zero Tilt Adapter. Then slide the whole imaging assemby back and adjust, slide back in and fix. Take an image and repeat until your perverted sense of perfection comes to fruition.

We will only dabble here once we can be sure of getting back to factory settings.

At the moment it is the last on my list of priorities. Getting the optical system and mount into mutual congress is more important.

Meanwhile the rest of us real people are doing more important things like wondering who won the most inane celebrity of the week award.

Bert

How is the trim these days?

[Peter Ward]

Originally Posted by avandonk

How is the trim these days?

Automatic