6.5 Hours on M101 Galaxy

[Catanonia]

Shot with the 1000D Modded with CLS clip LP filter via Skywatcher ED120 F7.5 900mm diamond refractor.

Guided by Lumicron Off Axis Guider / QHY5 / PHD

Processed with 6.5 hours of data comprised of 10 and 15 minute subs added with darks / flats and bias. Processed in DSS and CS3

Hope you like

[barkis]

It's a fine image Cat., but is the OAG pickup not too far into the light path, or could there be another reason for the black shadow impinging onto some of the brighter stars. There are three equispaced shadows on the bright left hand star. Can't be a spider, you're using a Frac. It could be a misalignment, as appears out of focus somewhat left hand side. Maybe another reason.

I've heard that getting the OAG Parfocal with the imaging camera can be a nightmare. Not criticising mate, just an observation which I'm sure you are aware of yourself.

Ron.

[Catanonia]

I am wondering myself mate as I have obviously noticed it myself.

It only occurs with the OAG, but with this one I can't move the pickup mirror in or out. Need to check and make sure I keep it out of the line of image, I can rotate it around the image CCD, so will experiment.

[barkis]

I'm interested in the OAG system of guiding, and therefore the relative performances of the types available to do the job.

The Lumicon has a good reputation, as with other equipment they sell, so I hope you get it sussed.

Ron.

[Psychobilly]

Nice image Cat .. background still a bit to black for my taste but taht a personal thing i suppose...

Hope you track down whats causing the nibbles on the stars....

I might finally have a working TS OAG setup ... but its not going onthe scope until I have finished my currrent project...

Peter...

[steppenwolf]

This is very nice indeed - with regard to the 'nicks' in the stars, if you hadn't said that it only happens with the OAG in line, I'd have said it was pinched optics. However, the nicks aside, you have some great detail in this image.

[Psychobilly]

Should be fairly easy to repair in the image and well worth it ...

[Catanonia]

This is very nice indeed - with regard to the 'nicks' in the stars, if you hadn't said that it only happens with the OAG in line, I'd have said it was pinched optics. However, the nicks aside, you have some great detail in this image.

mmm, worth exploring all aspects,

What is 'pinched optics' ?

[Psychobilly]

Here you go cat...

Star Testing - Telescope Shop Australia

Peter...

[Milliways]

good god! that is a really good image mate, the detail is superb and is pin-sharp.. well done!

[steppenwolf]

What is 'pinched optics' ?

The two lenses at the front of your telescope are held apart (they are an air spaced doublet) in a 'cradle' called a lens cell. If this is assembled too tightly, pressure is brought to bear on the glass and it distorts slightly so the light is refracted wrongly. The reason that there are three 'nicks' is because there are three retaining bots in the cell.

However, if it only happens when the OAG is in the light-path, it would make sense that the problem is with the OAG.

[Catanonia]

The two lenses at the front of your telescope are held apart (they are an air spaced doublet) in a 'cradle' called a lens cell. If this is assembled too tightly, pressure is brought to bear on the glass and it distorts slightly so the light is refracted wrongly. The reason that there are three 'nicks' is because there are three retaining bots in the cell.

However, if it only happens when the OAG is in the light-path, it would make sense that the problem is with the OAG.

yes I now consider myself 'pinched' educated

Cheers mate, can rule that one out as all fine with the ED80 as a guide scope.

Need to strip the assembly and ensure the pickup is outa the image line.

[Catanonia]

good god! that is a really good image mate, the detail is superb and is pin-sharp.. well done!

Thanks mate, 6.5 hours is a long time on one subject. Only one I did during that clear night.