NGC6888

[MikeD]

A late start for me last night, around 12:30am before I started the imaging run.

I also collimated the 80Ed( at the focuser) to get those Ha halos cirmetrical, still a nats out but a lot better now.

NGC6888: Ha 9 @ 15 min's bin x 1 through the 80Ed.

The image had a lot more background nebulosity when viewed in photoshop,so I have pushed it a bit harder for the web but it's still not as good as the original one viewed in photoshop and a bit more noisy now too

(click to enlarge)

[MartinB]

Mike, where are you living, Greece! I know what you mean about the effect of converting to a web image. Still, you still have a fair bit of background nebulosity there and it is an excellent image.

How did you go about the collimation?

[daz]

Thats superb Mike!!

[MikeD]

Thanks guys.

How did you go about the collimation?

Very easy :shock:.

I made an accurate diff spike generator out of a bit of 4" downpie and some dental floss.

Put that in the dew shield and a Chesire collimator( with cross hairs) in the focuser and adjusted the focuser by the three screws that attach it to the tube) until the crosshair of the Cheshire and the cross of the diff spike generator lined up when looking through the Cheshire collimator, job done ( took about two Min's to adjust)

[MartinB]

Very neat!

[Kaptain Klevtsov]

Superb image and a great tip on the collimation. I suspect the dental floss has to be accurately lined up to the axis of the 'scope?

Kaptain Klevtsov

[CELESCOPE]

thats a winner Mike , think its one of the best for detail i have seen, so well done on that , but !!heck!! i cant stay up till then have to rise by 5 for work.

well done ,super image

Rog

[MikeD]

Superb image and a great tip on the collimation. I suspect the dental floss has to be accurately lined up to the axis of the 'scope?

Kaptain Klevtsov

Yes I think so, the lens in the 80ed is fixed so as long as you make sure the diff generator is square to the dew shield and the dew shield is square to the lens you should be OK.

[Cloudwatcher]

That is a very neat idea! Would it work with the crosshairs attached to the dewshield.....not everyone has spare downpipes!

Know what you mean about visual difference between posted images and as seen in PS. Bit of a pain.

CW

[MikeD]

That is a very neat idea! Would it work with the crosshairs attached to the dewshield

I don't see why not as long as its accurately put on, the best way would be to drill 4 very small accurately spaced holes in the dew shield and thread the wire .

not everyone has spare downpipes!

CW

I just went to a building site and asked for some offcuts .

[centroid]

I like that one Mike, very nice indeed.

Well done!!

Dave

[Cloudwatcher]

I don't see why not as long as its accurately put on, the best way would be to drill 4 very small accurately spaced holes in the dew shield and thread the wire .

Drill! :shock: 4 very small accurately spaced holes!! in the dewshield!!! :pale: :pale:

I suppose Sellotape is out of the question?

CW

[Martin 2]

Thats a very nice shot, looks a difficult one to image?

M2

[MikeD]

Drill! :shock: 4 very small accurately spaced holes!! in the dewshield!!! :pale: :pale:

I suppose Sellotape is out of the question?

CW

Sometimes I forget, a perminant diff generator is not always wanted especially those who look through their scopes too.

As an imager I like diff spikes and want the spikes always to be in the same orientation (so the diff spikes always match up on data taken on other nights) so i need to be able to take the cap on and off for dark frames without disturbing the crosshairs thats why I have mine inside the dew shield.

But just for collimation aid Tape is good

or you could draw crosshaires across the objective in black marker pen

[Cloudwatcher]

or you could draw crosshaires across the objective in black marker pen

That's a relief! I'm not very good with drills!

[MikeD]

:)