What does "no guiding" mean

[doppler (Rick)]

Does this term only mean that a fully computerised tracking system is not being used? I use a single axis drive and adjust the motor speed to allow for PE. Is this unguided astrophotography?

[jjjnettie (Jeanette)]

Here's a great little article on the subject.
http://www.cloudynights.com/item.php?item_id=1398

[doppler (Rick)]

My question was more to do with that many images on this site are refered to as "unguided" but obviously some type of tracking has been used due to focal lengths used. Good article, so if I set my scope up to track really well and take some pics without looking through the finder or guide scope, then it is just tracking and therefore unguided?

[Dennis]

Tracking:
The RA motor of the telescope is just chugging along to compensate for the Earth’s rotation.

Manual guiding:
You are sitting at the off axis guider, guide scope, finder etc. eyeballing a star on an illuminated reticule and making small adjustments to RA (and DEC) manually using the hand paddle. This used to predominate in the days of film astrophotography and is rarely practiced these days (apart for IIS member Tornado!)

Auto guiding:
A CCD chip and software (after calibration set up) located at the off axis guider, guide scope, finder etc. monitors a guide star and automatically and tirelessly makes (hopefully) small adjustments to RA (and DEC) whenever the guide star drifts off the pixel.

Cheers

Dennis

[wayne anderson (Wayne)]

Hi Rick, yes your right about no guiding, all my shots are " alt/az no guiding " meaning my scope is not mounted on a eq mount or wedge just simple alt/az fork mount using standard computer tracking with no manual or auto guiding systems, you can see examples my shots in beginners photos section or my astrobin site below.

[cometcatcher (Kevin)]

"Unguided" can mean a couple of things...

1) No guiding or motorised tracking at all. The telescope or lens is dead still.

2) Motorised tracking with no attempts to adjust or compensate for drive error. This is the most common use of the term "unguided".

[doppler (Rick)]

Originally Posted by Dennis

Manual guiding:
You are sitting at the off axis guider, guide scope, finder etc. eyeballing a star on an illuminated reticule and making small adjustments to RA (and DEC) manually using the hand paddle. This used to predominate in the days of film astrophotography and is rarely practiced these days (apart for IIS member Tornado!)

Ah yes the good old film days with 5 minute minimum exposure times to capture anything, no stacking just single images you got to see a few days later. I still use an illuminated reticule to set up my scope but only have a DEC drive so I can only adjust the tracking speed. (the illuminated reticule is great for polar alignment too) Thankfully with DSLR s you only need 20 sec exposures to get reasonable images.

Rick

[Astroman (Andrew Wall)]

When I write unguided on the description of my images, it means I have not used an auto guiding program such as PHD (Push Here Dummy by stark-labs) and a guide scope to keep the mount pointing at the guide star. So usually exposure of around 2 minutes are easily obtained, longer if I spend more time of polar alignment, but longer does show Periodic error of the R.A. worm drive, without the Autoguiding.