A Problem with my Horse Head Neb

[BlackWidow (Mardy)]

I had my very first shot at the Horse Head Neb the other night. I only took this single image and has streched the heck out of it to show the problem even more..

I want to know what this light band is running up my image and how I can stop it from happening? I had no lights around to cause this and it only happened on this object. As soon as I went to any other object the problem was gone.. Is the bright star nearby causing this problem? and how do I stop it if it is?

I am using a Meade LX200GPS guided with PHD. I had a 6.3 focal reducer and this image was for around 300 sec

Any help would be great please

Regards
Mardy

[rally]

Martin,

That would be Alnitak !
That star that is the bain of our astro imaging lives when Horsey is the target !

Your result is noticeably bad - maybe it's your stretching.

Rally

[jjjnettie (Jeanette)]

Ahhh that would be caused by Alnitak.

[BlackWidow (Mardy)]

What can I do to assist in getting rid of this as if I increase the exposure it will only get worse.. I don't think I can get a wider view as I am already a 6.3 on an F10 scope... I could try the 3.3 reducer and just crop out the vignetting that this reducer causes.. That might allow the camera to deal with the bright spot better... Any ideas would be great.


Mardy

[jjjnettie (Jeanette)]

Some judicious framing is probably in order in this instance Mardy.
It can be a right pain at times.

[mithrandir (Andrew)]

Mardy, do you have a dew shield on the scope? That helps somewhat with out of field stars by acting as a lens hood. My dew shield is about the same length as the SCT tube.

[bmitchell82 (Brendan)]

It took me a little while to figure out what was happening when these abberations happend, but the crux of it is even though your sensor doesn't have the star on it, doesn't mean the light from that star isn't landing just off the edge of sensor. When this happens itll be hitting something just off the side of your sensor and send light skimming across... shabam there you have it , so move the horse down lower to the bottom of the image then you will find that the flare will decrease other wise you might have to try turning it around about.

Good luck

[BlackWidow (Mardy)]

Thanks Brendan and Andrew.. I do have a very large dew shield that is as long as the scope. Lightweight flex shield I made.. I will give what Brendan suggested as I thought this type of thing might be the case. I could also try removing the IR filter on the CCD or play with some spacing as well. At least I now know that this is a common problem and need to play around to solve it... Seems that this hobby is challenge based.

Thanks all
Mardy