Advice Needed Please

[austen4]

Hello all,

Once again I need some advice. On the last 4-5 nights I have been out trying to gets some subs of M42 as I am a complete beginner. However I would only get around 70 second subs before trailing. Once this has become apparent I have re-polar aligned but trails still occur. I have read some pages on "precision polar alignment" but I have recently modified my scope for imaging (mirror movement) and cannot carry out the drift alignment unless I buy an extender/spacer for the eye piece. I do have a polar scope, I understand how to use it but I place the mini constellations in the right place but I still get trails. It has been set up properly but will do it again tomorrow.

I have also considered a guide scope but this soon would put to another side once I saw the prices of them. I also looked at a DIY thread in which a 9x50 finder scope could be converted for guide scope use. If I did this, what webcam would I need? Would it have to be specialised for guiding? How much would one cost and are guide scopes really worth it?

Sorry if I may be asking simple question but please bare with me .

Thanks and all advice will be muchly appreciated

[austen4]

The max exposure I got when I checked the subs was 110 seconds but this was after nearly two hours. This seems quite bad as I have seen the heq5 produce much higher exposures.