M27 Dumbbell Nebula uploaded

[MarkS]

I bought the Celestron C11 just 3 weeks ago.  This was the first successful image I took with it:

http://gallery.orpington-astronomy.org.uk/displayimage-348.html

[Ian]

well thats not too shabby mate   

Single shot with the 300D?

[MarkS]

Not a single shot, no.  It was 40x30sec exposures - unguided on the standard CG5 equatorial mount the OTA comes with.  Another 40 exposures had to be discarded because of trailing.

[Fay]

Mark,

that is really nice. It is one I would like to do with the Canon.



Fay

[Ian]

very impressive mate, getting decent 30s exposures with a CG5. That's got to be right at the limit with a C11 on it surely?

[MarkS]

The CG5 (Goto) mount actually seems pretty solid, even with a C11 on it.  The problem is the periodic error - unfortunately there is no facility for periodic error correction.  I reckon the periodic error is approximately 50 arcsec peak to trough over a cycle of roughly 10 minutes - but in that cycle there are some periods of relative stability.

[Mike]

I think the CG5 (GoTo) has the same inner working of the HEQ5 mount as I believe Celestron and Skywatcher are the same company (Orion USA?) so it should be pretty stable. Have you thought of stripping it down and regreasing, etc. to see if that improves it? The ultimate way of getting rid of it of course would be to get a guide camera and scope and guide the mount. If you already have a webcam and a small refractor you could use that.

[Rick]

Mark, I fear the description in the gallery for this image got lost in the whatever-it-was that left me restoring the pictures table earlier. Please can you check and fixi it when you have a moment.

[MarkS]

I fear the description in the gallery for this image got lost

Don't worry - I've repaired the description now.

I think the CG5 (GoTo) has the same inner working of the HEQ5 mount

I thought the HEQ5 was a league apart from the CG5.  I may try stripping it down sometime.  But in any case I have an EQ6 Pro on order.  I've blown the budget on an OTA and mount so autoguiding will have to wait a while 

[Rocket Pooch]

The HEQ5 is not the CG5 at all.  Also if you have a HEQ5 or EQ6 don;t strip t down unless its playing up, I did, its a pain and does not really improve things to a large degree.

Chris